Toxicological and ecotoxicological risk-based prioritization of pharmaceuticals in the natural environment.

Science.gov (United States)

Guo, Jiahua; Sinclair, Chris J; Selby, Katherine; Boxall, Alistair B A

2016-06-01

Approximately 1500 active pharmaceutical ingredients are currently in use; however, the environmental occurrence and impacts of only a small proportion of these have been investigated. Recognizing that it would be impractical to monitor and assess all pharmaceuticals that are in use, several previous studies have proposed the use of prioritization approaches to identify substances of most concern so that resources can be focused on these. All of these previous approaches suffer from limitations. In the present study, the authors draw on experience from previous prioritization exercises and present a holistic approach for prioritizing pharmaceuticals in the environment in terms of risks to aquatic and soil organisms, avian and mammalian wildlife, and humans. The approach considers both apical ecotoxicological endpoints as well as potential nonapical effects related to the therapeutic mode of action. Application of the approach is illustrated for 146 active pharmaceuticals that are used either in the community or in hospital settings in the United Kingdom. Using the approach, 16 compounds were identified as a potential priority. These substances include compounds belonging to the antibiotic, antidepressant, anti-inflammatory, antidiabetic, antiobesity, and estrogen classes as well as associated metabolites. In the future, the prioritization approach should be applied more broadly around the different regions of the world. Environ Toxicol Chem 2016;35:1550-1559. © 2016 SETAC. © 2016 SETAC.

Are exposure predictions, used for the prioritization of pharmaceuticals in the environment, fit for purpose?

Science.gov (United States)

Burns, Emily E; Thomas-Oates, Jane; Kolpin, Dana W; Furlong, Edward T; Boxall, Alistair B A

2017-10-01

Prioritization methodologies are often used for identifying those pharmaceuticals that pose the greatest risk to the natural environment and to focus laboratory testing or environmental monitoring toward pharmaceuticals of greatest concern. Risk-based prioritization approaches, employing models to derive exposure concentrations, are commonly used, but the reliability of these models is unclear. The present study evaluated the accuracy of exposure models commonly used for pharmaceutical prioritization. Targeted monitoring was conducted for 95 pharmaceuticals in the Rivers Foss and Ouse in the City of York (UK). Predicted environmental concentration (PEC) ranges were estimated based on localized prescription, hydrological data, reported metabolism, and wastewater treatment plant (WWTP) removal rates, and were compared with measured environmental concentrations (MECs). For the River Foss, PECs, obtained using highest metabolism and lowest WWTP removal, were similar to MECs. In contrast, this trend was not observed for the River Ouse, possibly because of pharmaceutical inputs unaccounted for by our modeling. Pharmaceuticals were ranked by risk based on either MECs or PECs. With 2 exceptions (dextromethorphan and diphenhydramine), risk ranking based on both MECs and PECs produced similar results in the River Foss. Overall, these findings indicate that PECs may well be appropriate for prioritization of pharmaceuticals in the environment when robust and local data on the system of interest are available and reflective of most source inputs. Environ Toxicol Chem 2017;36:2823-2832. © 2017 SETAC. © 2017 SETAC.

Human Metabolism and Interactions of Deployment-Related Chemicals

Science.gov (United States)

2008-08-01

stimulated by CPO (Fig. 6). Coincidently, α- naphthoflavone inhibited CYP1A2 metabolism of flavonoids /23/ and stimulated CYP3A4 metabolism of...by flavonoids of benzo[a]pyrene hydroxylation by cytochrome P-450 isozymes from rabbit liver microsomes, J. Biol. Chem. 1981; 256: 10897-10901. 17...P450-mediated metabolism of dietary flavonoids , Food Chem. Toxicol. 2002; 40: 609-616. 24. Cameron MD, Wen B, Allen KE, Roberts AG, Schuman JT

ChemPreview: an augmented reality-based molecular interface.

Science.gov (United States)

Zheng, Min; Waller, Mark P

2017-05-01

Human computer interfaces make computational science more comprehensible and impactful. Complex 3D structures such as proteins or DNA are magnified by digital representations and displayed on two-dimensional monitors. Augmented reality has recently opened another door to access the virtual three-dimensional world. Herein, we present an augmented reality application called ChemPreview with the potential to manipulate bio-molecular structures at an atomistic level. ChemPreview is available at https://github.com/wallerlab/chem-preview/releases, and is built on top of the Meta 1 platform https://www.metavision.com/. ChemPreview can be used to interact with a protein in an intuitive way using natural hand gestures, thereby making it appealing to computational chemists or structural biologists. The ability to manipulate atoms in real world could eventually provide new and more efficient ways of extracting structural knowledge, or designing new molecules in silico. Copyright © 2017 Elsevier Inc. All rights reserved.

radEq Add-On Module for CFD Solver Loci-CHEM

Science.gov (United States)

McCloud, Peter

2013-01-01

Loci-CHEM to be applied to flow velocities where surface radiation due to heating from compression and friction becomes significant. The module adds a radiation equilibrium boundary condition to the computational fluid dynamics (CFD) code to produce accurate results. The module expanded the upper limit for accurate CFD solutions of Loci-CHEM from Mach 4 to Mach 10 based on Space Shuttle Orbiter Re-Entry trajectories. Loci-CHEM already has a very promising architecture and performance, but absence of radiation equilibrium boundary condition limited the application of Loci-CHEM to below Mach 4. The immediate advantage of the add-on module is that it allows Loci-CHEM to work with supersonic flows up to Mach 10. This transformed Loci-CHEM from a rocket engine- heritage CFD code with general subsonic and low-supersonic applications, to an aeroheating code with hypersonic applications. The follow-on advantage of the module is that it is a building block for additional add-on modules that will solve for the heating generated at Mach numbers higher than 10.

Efectos toxicológicos y neuropsiquiátricos producidos por consumo de cocaína

OpenAIRE

Téllez Mosquera, Jairo; Cote Menéndez, Miguel

2014-01-01

Este artículo realiza una revisión sobre la historia, la cultura, los aspectos clínico toxicológicos y los efectos en el comportamiento producidos por el uso agudo y crónico de la cocaína. La cocaína como sustancia psicoactiva sin importar su forma de consumo, una vez dentro del organismo sigue las mismas vías metabólicas, produciendo efecto sobre los diferentes órganos. La toxicidad de la cocaína es debida a su metabolito el benzoilecgonina un potente agonista a...

Engaging Organic Chemistry Students Using ChemDraw for iPad

Science.gov (United States)

Morsch, Layne A.; Lewis, Michael

2015-01-01

Drawing structures, mechanisms, and syntheses is a vital part of success in organic chemistry courses. ChemDraw for iPad has been used to increase classroom experiences in the preparation of high quality chemical drawings. The embedded Flick-to-Share allows for simple, real-time exchange of ChemDraw documents. ChemDraw for iPad also allows…

Modeling photodegradation kinetics of three systemic neonicotinoids-dinotefuran, imidacloprid, and thiamethoxam-in aqueous and soil environment.

Science.gov (United States)

Kurwadkar, Sudarshan; Evans, Amanda; DeWinne, Dustan; White, Peter; Mitchell, Forrest

2016-07-01

Environmental presence and retention of commonly used neonicotinoid insecticides such as dinotefuran (DNT), imidacloprid (IMD), and thiamethoxam (THM) are a cause for concern and prevention because of their potential toxicity to nontarget species. In the present study the kinetics of the photodegradation of these insecticides were investigated in water and soil compartments under natural light conditions. The results suggest that these insecticides are fairly unstable in both aqueous and soil environments when exposed to natural sunlight. All 3 insecticides exhibit strong first-order degradation rate kinetics in the aqueous phase, with rate constants kDNT , kIMD , and kTHM of 0.20 h(-1) , 0.30 h(-1) , and 0.18 h(-1) , respectively. However, in the soil phase, the modeled photodegradation kinetics appear to be biphasic, with optimal rate constants k1DNT and k2DNT of 0.0198 h(-1) and 0.0022 h(-1) and k1THM and k2THM of 0.0053 h(-1) and 0.0014 h(-1) , respectively. Differentially, in the soil phase, imidacloprid appears to follow the first-order rate kinetics with a kIMD of 0.0013 h(-1) . These results indicate that all 3 neonicotinoids are photodegradable, with higher degradation rates in aqueous environments relative to soil environments. In addition, soil-encapsulated imidacloprid appears to degrade slowly compared with dinotefuran and thiamethoxam and does not emulate the faster degradation rates observed in the aqueous phase. Environ Toxicol Chem 2016;35:1718-1726. © 2015 SETAC. © 2015 SETAC.

Searching Online Chemical Data Repositories via the ChemAgora Portal.

Science.gov (United States)

Zanzi, Antonella; Wittwehr, Clemens

2017-12-26

ChemAgora, a web application designed and developed in the context of the "Data Infrastructure for Chemical Safety Assessment" (diXa) project, provides search capabilities to chemical data from resources available online, enabling users to cross-reference their search results with both regulatory chemical information and public chemical databases. ChemAgora, through an on-the-fly search, informs whether a chemical is known or not in each of the external data sources and provides clikable links leading to the third-party web site pages containing the information. The original purpose of the ChemAgora application was to correlate studies stored in the diXa data warehouse with available chemical data. Since the end of the diXa project, ChemAgora has evolved into an independent portal, currently accessible directly through the ChemAgora home page, with improved search capabilities of online data sources.

DuraChem trademark - challenges and solutions

International Nuclear Information System (INIS)

Howard, I.S.; Bowan, B.W.; Kirshe, M.H.

1996-01-01

Vitrification of low-level ion exchange resins represents numerous challenges never before successfully accomplished. These challenges include (1) Feed material preparation and transfer, (2) Melter temperature and volume control, (3) Glass composition, stabilization, and control, and (4) Off-gas treatment and particulate capture. The DuraChem trademark team of Chem-Nuclear Systems, Inc. and GTS Duratek, Inc. began its journey in 1994 and is in the process of starting-up the first centralized vitrification facility for commercial ion-exchange and filtration media. This paper addresses each of the challenges and provides an update of this unique volume-reduction and stabilization technology

ChemSearch Journal: Submissions

African Journals Online (AJOL)

AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search · USING ... SCOPE: ChemSearch Journal is a peer-reviewed journal that publishes ... Authors whose papers have been accepted for publication will be notified in writing. ... The literature cited must be discussed to show the relationships between the ...

The Another Assimilation System for WRF-Chem (AAS4WRF): a new mass-conserving emissions pre-processor for WRF-Chem regional modelling

Science.gov (United States)

Vara Vela, A. L.; Muñoz, A.; Lomas, A., Sr.; González, C. M.; Calderon, M. G.; Andrade, M. D. F.

2017-12-01

The Weather Research and Forecasting with Chemistry (WRF-Chem) community model have been widely used for the study of pollutants transport, formation of secondary pollutants, as well as for the assessment of air quality policies implementation. A key factor to improve the WRF-Chem air quality simulations over urban areas is the representation of anthropogenic emission sources. There are several tools that are available to assist users in creating their own emissions based on global emissions information (e.g. anthro_emiss, prep_chem_src); however, there is no single tool that will construct local emissions input datasets for any particular domain at this time. Because the official emissions pre-processor (emiss_v03) is designed to work with domains located over North America, this work presents the Another Assimilation System for WRF-Chem (AAS4WRF), a ncl based mass-conserving emissions pre-processor designed to create WRF-Chem ready emissions files from local inventories on a lat/lon projection. AAS4WRF is appropriate to scale emission rates from both surface and elevated sources, providing the users an alternative way to assimilate their emissions to WRF-Chem. Since it was successfully tested for the first time for the city of Lima, Peru in 2014 (managed by SENAMHI, the National Weather Service of the country), several studies on air quality modelling have applied this utility to convert their emissions to those required for WRF-Chem. Two case studies performed in the metropolitan areas of Sao Paulo and Manizales in Brazil and Colombia, respectively, are here presented in order to analyse the influence of using local or global emission inventories in the representation of regulated air pollutants such as O3 and PM2.5. Although AAS4WRF works with local emissions information at the moment, further work is being conducted to make it compatible with global/regional emissions data file format. The tool is freely available upon request to the corresponding author.

AutoClickChem: click chemistry in silico.

Directory of Open Access Journals (Sweden)

Jacob D Durrant

Full Text Available Academic researchers and many in industry often lack the financial resources available to scientists working in "big pharma." High costs include those associated with high-throughput screening and chemical synthesis. In order to address these challenges, many researchers have in part turned to alternate methodologies. Virtual screening, for example, often substitutes for high-throughput screening, and click chemistry ensures that chemical synthesis is fast, cheap, and comparatively easy. Though both in silico screening and click chemistry seek to make drug discovery more feasible, it is not yet routine to couple these two methodologies. We here present a novel computer algorithm, called AutoClickChem, capable of performing many click-chemistry reactions in silico. AutoClickChem can be used to produce large combinatorial libraries of compound models for use in virtual screens. As the compounds of these libraries are constructed according to the reactions of click chemistry, they can be easily synthesized for subsequent testing in biochemical assays. Additionally, in silico modeling of click-chemistry products may prove useful in rational drug design and drug optimization. AutoClickChem is based on the pymolecule toolbox, a framework that may facilitate the development of future python-based programs that require the manipulation of molecular models. Both the pymolecule toolbox and AutoClickChem are released under the GNU General Public License version 3 and are available for download from http://autoclickchem.ucsd.edu.

AutoClickChem: click chemistry in silico.

Science.gov (United States)

Durrant, Jacob D; McCammon, J Andrew

2012-01-01

Academic researchers and many in industry often lack the financial resources available to scientists working in "big pharma." High costs include those associated with high-throughput screening and chemical synthesis. In order to address these challenges, many researchers have in part turned to alternate methodologies. Virtual screening, for example, often substitutes for high-throughput screening, and click chemistry ensures that chemical synthesis is fast, cheap, and comparatively easy. Though both in silico screening and click chemistry seek to make drug discovery more feasible, it is not yet routine to couple these two methodologies. We here present a novel computer algorithm, called AutoClickChem, capable of performing many click-chemistry reactions in silico. AutoClickChem can be used to produce large combinatorial libraries of compound models for use in virtual screens. As the compounds of these libraries are constructed according to the reactions of click chemistry, they can be easily synthesized for subsequent testing in biochemical assays. Additionally, in silico modeling of click-chemistry products may prove useful in rational drug design and drug optimization. AutoClickChem is based on the pymolecule toolbox, a framework that may facilitate the development of future python-based programs that require the manipulation of molecular models. Both the pymolecule toolbox and AutoClickChem are released under the GNU General Public License version 3 and are available for download from http://autoclickchem.ucsd.edu.

Design, synthesis and characterisation of MAMC as a novel and selective cytochrome P450 2D6 substrate suitable for high throughput screening.

NARCIS (Netherlands)

Onderwater, R.C.A.; Venhorst, J.; Commandeur, J.N.M.; Vermeulen, N.P.E.

1999-01-01

In this study, a selective substrate for cytochrome P450 2D6 was designed using a small molecule model developed by M. J. De Groot et al. [(1997) Chem. Res. Toxicol. 10, 41-48]. The substrate, 7-methoxy-4- (aminomethyl)coumarin (MAMC), and its putative O-demethylated metabolite 7-

Tanshinones as Effective Therapeutic Agents for Prostate Cancer

Science.gov (United States)

2011-06-01

Y. Tian, T.-F. Chen, W. Ye, L. Li, F. Ni, J.-R. Zhou: Construction and screening of fractional library of Salvia Miltiorrhiza for the rapid...glutathione perturbation. Food Chem Toxicol 2008;46: 328–38. 19. Singh AV, Franke AA, Blackburn GL, Zhou JR. Soy phytochemicals prevent orthotopic growth and

Determination of Heavy Metal Genotoxicity and their Accumulation ...

African Journals Online (AJOL)

ADOWIE PERE

Johannesburg, P.O. Box 17011, Doornfontein 2028, Johannesburg, Republic of South Africa. ... effects that could result from exposure of fish to heavy metals in the Asa River, Ilorin, Nigeria. ... through food chains and this creates public health ...... cultivated in sewage-fed fish farms. Food Chem. Toxicol. 45. (2),. 210-215.

PubChem Power User Gateway (PUG)

Data.gov (United States)

U.S. Department of Health & Human Services — PUG provides access to PubChem services via a programmatic interface. Users may download data, initiate chemical structure searches, standardize chemical structures...

ChemProt-3.0: a global chemical biology diseases mapping

DEFF Research Database (Denmark)

Kringelum, Jens Vindahl; Kjærulff, Sonny Kim; Brunak, Søren

2016-01-01

ChemProt is a publicly available compilation of chemical-protein-disease annotation resources that enables the study of systems pharmacology for a small molecule across multiple layers of complexity from molecular to clinical levels. In this third version, ChemProt has been updated to more than 1...

"CHEM"opera for Chemistry Education

Science.gov (United States)

Chung, Yong Hee

2013-01-01

"CHEM"opera is an opera blended with demonstrations of chemical reactions. It has been produced and performed twice by chemistry undergraduate students at Hallym University in South Korea. It aims to demonstrate interesting chemical reactions to chemistry students, children and the public and to facilitate their understanding of the role…

Development of a Grid-Independent Geos-Chem Chemical Transport Model (v9-02) as an Atmospheric Chemistry Module for Earth System Models

Science.gov (United States)

Long, M. S.; Yantosca, R.; Nielsen, J. E; Keller, C. A.; Da Silva, A.; Sulprizio, M. P.; Pawson, S.; Jacob, D. J.

2015-01-01

The GEOS-Chem global chemical transport model (CTM), used by a large atmospheric chemistry research community, has been re-engineered to also serve as an atmospheric chemistry module for Earth system models (ESMs). This was done using an Earth System Modeling Framework (ESMF) interface that operates independently of the GEOSChem scientific code, permitting the exact same GEOSChem code to be used as an ESM module or as a standalone CTM. In this manner, the continual stream of updates contributed by the CTM user community is automatically passed on to the ESM module, which remains state of science and referenced to the latest version of the standard GEOS-Chem CTM. A major step in this re-engineering was to make GEOS-Chem grid independent, i.e., capable of using any geophysical grid specified at run time. GEOS-Chem data sockets were also created for communication between modules and with external ESM code. The grid-independent, ESMF-compatible GEOS-Chem is now the standard version of the GEOS-Chem CTM. It has been implemented as an atmospheric chemistry module into the NASA GEOS- 5 ESM. The coupled GEOS-5-GEOS-Chem system was tested for scalability and performance with a tropospheric oxidant-aerosol simulation (120 coupled species, 66 transported tracers) using 48-240 cores and message-passing interface (MPI) distributed-memory parallelization. Numerical experiments demonstrate that the GEOS-Chem chemistry module scales efficiently for the number of cores tested, with no degradation as the number of cores increases. Although inclusion of atmospheric chemistry in ESMs is computationally expensive, the excellent scalability of the chemistry module means that the relative cost goes down with increasing number of cores in a massively parallel environment.

Microplastics as vectors for bioaccumulation of hydrophobic organic chemicals in the marine environment: A state-of-the-science review.

Science.gov (United States)

Ziccardi, Linda M; Edgington, Aaron; Hentz, Karyn; Kulacki, Konrad J; Kane Driscoll, Susan

2016-07-01

A state-of-the-science review was conducted to examine the potential for microplastics to sorb hydrophobic organic chemicals (HOCs) from the marine environment, for aquatic organisms to take up these HOCs from the microplastics, and for this exposure to result in adverse effects to ecological and human health. Despite concentrations of HOCs associated with microplastics that can be orders of magnitude greater than surrounding seawater, the relative importance of microplastics as a route of exposure is difficult to quantify because aquatic organisms are typically exposed to HOCs from various compartments, including water, sediment, and food. Results of laboratory experiments and modeling studies indicate that HOCs can partition from microplastics to organisms or from organisms to microplastics, depending on experimental conditions. Very little information is available to evaluate ecological or human health effects from this exposure. Most of the available studies measured biomarkers that are more indicative of exposure than effects, and no studies showed effects to ecologically relevant endpoints. Therefore, evidence is weak to support the occurrence of ecologically significant adverse effects on aquatic life as a result of exposure to HOCs sorbed to microplastics or to wildlife populations and humans from secondary exposure via the food chain. More data are needed to fully understand the relative importance of exposure to HOCs from microplastics compared with other exposure pathways. Environ Toxicol Chem 2016;35:1667-1676. © 2016 SETAC. © 2016 SETAC.

Early Detection of Breast Cancer Using Posttranslationally Modified Biomarkers

Science.gov (United States)

2011-03-01

1 and 2 in Globo H synthesis , Proc Natl Acad Sci U S A 105, 11667-11672. 18. Gilewski, T., Ragupathi, G., Bhuta, S., Williams, L. J., Musselli, C...carmustine and new proline analog of nitrosourea on antioxidant system in breast carcinoma cells (MCF-7), Drug Chem Toxicol 33, 55-63. 34. Galijasevic, S

Early Warning: Brought to you by the DoD Chem-Bio Defense Program

Science.gov (United States)

Security Robots Lasers RSS Feed Early Warning: Brought to you by the DoD Chem-Bio Defense Program help warfighters prevent, protect against, respond to or recover from chem-bio threats and effects . Hassell said he and his team don't monitor the world for chem-bio threats, they develop the tools that

An automated approach to Litchfield and Wilcoxon's evaluation of dose–effect experiments using the R package LW1949

Science.gov (United States)

Adams, Jean V.; Slaght, Karen; Boogaard, Michael A.

2016-01-01

The authors developed a package, LW1949, for use with the statistical software R to automatically carry out the manual steps of Litchfield and Wilcoxon's method of evaluating dose–effect experiments. The LW1949 package consistently finds the best fitting dose–effect relation by minimizing the chi-squared statistic of the observed and expected number of affected individuals and substantially speeds up the line-fitting process and other calculations that Litchfield and Wilcoxon originally carried out by hand. Environ Toxicol Chem 2016;9999:1–4. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America.

3D-e-Chem-VM: Structural Cheminformatics Research Infrastructure in a Freely Available Virtual Machine

NARCIS (Netherlands)

McGuire, R.; Verhoeven, S.; Vass, M.; Vriend, G.; Esch, I.J. de; Lusher, S.J.; Leurs, R.; Ridder, L.; Kooistra, A.J.; Ritschel, T.; Graaf, C. de

2017-01-01

3D-e-Chem-VM is an open source, freely available Virtual Machine ( http://3d-e-chem.github.io/3D-e-Chem-VM/ ) that integrates cheminformatics and bioinformatics tools for the analysis of protein-ligand interaction data. 3D-e-Chem-VM consists of software libraries, and database and workflow tools

3D-e-Chem-VM : Structural Cheminformatics Research Infrastructure in a Freely Available Virtual Machine

NARCIS (Netherlands)

McGuire, Ross; Verhoeven, Stefan; Vass, Márton; Vriend, Gerrit; De Esch, Iwan J P; Lusher, Scott J.; Leurs, Rob; Ridder, Lars; Kooistra, Albert J.; Ritschel, Tina; de Graaf, C.

2017-01-01

3D-e-Chem-VM is an open source, freely available Virtual Machine ( http://3d-e-chem.github.io/3D-e-Chem-VM/ ) that integrates cheminformatics and bioinformatics tools for the analysis of protein-ligand interaction data. 3D-e-Chem-VM consists of software libraries, and database and workflow tools

ChemAND - a system health monitor for plant chemistry

Energy Technology Data Exchange (ETDEWEB)

Turner, C.W.; Mitchel, G.R.; Tosello, G.; Balakrishnan, P.V.; McKay, G.; Thompson, M. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Dundar, Y.; Bergeron, M.; Laporte, R. [Hydro-Quebec, Groupe Chimie, Centrale Nucleaire Gentilly-2, Gentilly, Quebec (Canada)

2001-03-01

Effective management of plant systems throughout their lifetime requires much more than data acquisition and display - it requires that the plant's system health be continually monitored and managed. AECL has developed a System Health Monitor called ChemAND for CANDU plant chemistry. ChemAND, a Chemistry ANalysis and Diagnostic system, monitors key chemistry parameters in the heat transport system, moderator-cover gas, annulus gas, and the steam cycle during full-power operation. These parameters can be used as inputs to models that calculate the effect of current plant operating conditions on the present and future health of the system. Chemistry data from each of the systems are extracted on a regular basis from the plant's Historical Data Server and are sorted according to function, e.g., indicators for condenser in-leakage, air in-leakage, heavy water leakage into the annulus gas, fuel failure, etc. Each parameter is conveniently displayed and is trended along with its alarm limits. ChemAND currently includes two analytical models developed for the balance-of-plant. The first model, ChemSolv, calculates crevice chemistry conditions in the steam generator (SG) from either the SG blowdown chemistry conditions or from a simulated condenser leak. This information can be used by plant staff to evaluate the susceptibility of the SG tubes to crevice corrosion. ChemSolv also calculates chemistry conditions throughout the steam-cycle system as determined by the transport of volatile species such as ammonia, hydrazine, morpholine, and oxygen. The second model, SLUDGE, calculates the deposit loading and distribution in the SG as a function of time, based on concentrations of corrosion product in the final feedwater for both normal and start-up conditions. Operations personnel can use this information to predict where to inspect and when to clean. (author)

ChemAND - a system health monitor for plant chemistry

International Nuclear Information System (INIS)

Turner, C.W.; Mitchell, G.R.; Tosello, G.; Balakrishnan, P.V.; McKay, G.; Thompson, M.; Dundar, Y.; Bergeron, M.; Laporte, R.

2001-01-01

Effective management of plant systems throughout their lifetime requires much more than data acquisition and display-it requires that the plant's system health be continually monitored and managed. AECL has developed a System Health Monitor called ChemAND for CANDU plant chemistry. ChemAND, a Chemistry ANalysis and Diagnostic system, monitors key chemistry parameters in the heat transport system, moderator-cover gas, annulus gas, and the steam cycle during full-power operation. These parameters can be used as inputs to models that calculate the effect of current plant operating conditions on the present and future health of the system. Chemistry data from each of the systems are extracted on a regular basis from the plant's Historical Data Server and are sorted according to function, e.g., indicators for condenser in-leakage, air in-leakage, heavy water leakage into the annulus gas, fuel failure, etc. Each parameter is conveniently displayed and is trended along with its alarm limits. ChemAND currently includes two analytical models developed for the balance-of-plant. The first model, ChemSolv, calculates crevice chemistry conditions in the steam generator (SG) from either the SG blowdown chemistry conditions or from a simulated condenser leak. This information can be used by plant staff to evaluate the susceptibility of the SG tubes to crevice corrosion. ChemSolv also calculates chemistry conditions throughout the steam cycle system, as determined by the transport of volatile species such as ammonia, hydrazine, morpholine, and oxygen. The second model, SLUDGE, calculates the deposit loading and distribution in the SG as a function of time, based on concentrations of corrosion product in the final feedwater for both normal and start-up conditions. Operations personnel can use this information to predict where to inspect and when to clean. (author)

ChemAND - a system health monitor for plant chemistry

International Nuclear Information System (INIS)

Turner, C.W.; Mitchel, G.R.; Tosello, G.; Balakrishnan, P.V.; McKay, G.; Thompson, M.; Dundar, Y.; Bergeron, M.; Laporte, R.

2001-03-01

Effective management of plant systems throughout their lifetime requires much more than data acquisition and display - it requires that the plant's system health be continually monitored and managed. AECL has developed a System Health Monitor called ChemAND for CANDU plant chemistry. ChemAND, a Chemistry ANalysis and Diagnostic system, monitors key chemistry parameters in the heat transport system, moderator-cover gas, annulus gas, and the steam cycle during full-power operation. These parameters can be used as inputs to models that calculate the effect of current plant operating conditions on the present and future health of the system. Chemistry data from each of the systems are extracted on a regular basis from the plant's Historical Data Server and are sorted according to function, e.g., indicators for condenser in-leakage, air in-leakage, heavy water leakage into the annulus gas, fuel failure, etc. Each parameter is conveniently displayed and is trended along with its alarm limits. ChemAND currently includes two analytical models developed for the balance-of-plant. The first model, ChemSolv, calculates crevice chemistry conditions in the steam generator (SG) from either the SG blowdown chemistry conditions or from a simulated condenser leak. This information can be used by plant staff to evaluate the susceptibility of the SG tubes to crevice corrosion. ChemSolv also calculates chemistry conditions throughout the steam-cycle system as determined by the transport of volatile species such as ammonia, hydrazine, morpholine, and oxygen. The second model, SLUDGE, calculates the deposit loading and distribution in the SG as a function of time, based on concentrations of corrosion product in the final feedwater for both normal and start-up conditions. Operations personnel can use this information to predict where to inspect and when to clean. (author)

Chem/bio sensing with non-classical light and integrated photonics.

Science.gov (United States)

Haas, J; Schwartz, M; Rengstl, U; Jetter, M; Michler, P; Mizaikoff, B

2018-01-29

Modern quantum technology currently experiences extensive advances in applicability in communications, cryptography, computing, metrology and lithography. Harnessing this technology platform for chem/bio sensing scenarios is an appealing opportunity enabling ultra-sensitive detection schemes. This is further facilliated by the progress in fabrication, miniaturization and integration of visible and infrared quantum photonics. Especially, the combination of efficient single-photon sources together with waveguiding/sensing structures, serving as active optical transducer, as well as advanced detector materials is promising integrated quantum photonic chem/bio sensors. Besides the intrinsic molecular selectivity and non-destructive character of visible and infrared light based sensing schemes, chem/bio sensors taking advantage of non-classical light sources promise sensitivities beyond the standard quantum limit. In the present review, recent achievements towards on-chip chem/bio quantum photonic sensing platforms based on N00N states are discussed along with appropriate recognition chemistries, facilitating the detection of relevant (bio)analytes at ultra-trace concentration levels. After evaluating recent developments in this field, a perspective for a potentially promising sensor testbed is discussed for reaching integrated quantum sensing with two fiber-coupled GaAs chips together with semiconductor quantum dots serving as single-photon sources.

Consequences of ChemR23 heteromerization with the chemokine receptors CXCR4 and CCR7.

Science.gov (United States)

de Poorter, Cédric; Baertsoen, Kevin; Lannoy, Vincent; Parmentier, Marc; Springael, Jean-Yves

2013-01-01

Recent studies have shown that heteromerization of the chemokine receptors CCR2, CCR5 and CXCR4 is associated to negative binding cooperativity. In the present study, we build on these previous results, and investigate the consequences of chemokine receptor heteromerization with ChemR23, the receptor of chemerin, a leukocyte chemoattractant protein structurally unrelated to chemokines. We show, using BRET and HTRF assays, that ChemR23 forms homomers, and provide data suggesting that ChemR23 also forms heteromers with the chemokine receptors CCR7 and CXCR4. As previously described for other chemokine receptor heteromers, negative binding cooperativity was detected between ChemR23 and chemokine receptors, i.e. the ligands of one receptor competed for the binding of a specific tracer of the other. We also showed, using mouse bone marrow-derived dendritic cells prepared from wild-type and ChemR23 knockout mice, that ChemR23-specific ligands cross-inhibited CXCL12 binding on CXCR4 in a ChemR23-dependent manner, supporting the relevance of the ChemR23/CXCR4 interaction in native leukocytes. Finally, and in contrast to the situation encountered for other previously characterized CXCR4 heteromers, we showed that the CXCR4-specific antagonist AMD3100 did not cross-inhibit chemerin binding in cells co-expressing ChemR23 and CXCR4, demonstrating that cross-regulation by AMD3100 depends on the nature of receptor partners with which CXCR4 is co-expressed.

ChemTS: an efficient python library for de novo molecular generation

Science.gov (United States)

Yang, Xiufeng; Zhang, Jinzhe; Yoshizoe, Kazuki; Terayama, Kei; Tsuda, Koji

2017-12-01

Automatic design of organic materials requires black-box optimization in a vast chemical space. In conventional molecular design algorithms, a molecule is built as a combination of predetermined fragments. Recently, deep neural network models such as variational autoencoders and recurrent neural networks (RNNs) are shown to be effective in de novo design of molecules without any predetermined fragments. This paper presents a novel Python library ChemTS that explores the chemical space by combining Monte Carlo tree search and an RNN. In a benchmarking problem of optimizing the octanol-water partition coefficient and synthesizability, our algorithm showed superior efficiency in finding high-scoring molecules. ChemTS is available at https://github.com/tsudalab/ChemTS.

Consequences of ChemR23 heteromerization with the chemokine receptors CXCR4 and CCR7.

Directory of Open Access Journals (Sweden)

Cédric de Poorter

Full Text Available Recent studies have shown that heteromerization of the chemokine receptors CCR2, CCR5 and CXCR4 is associated to negative binding cooperativity. In the present study, we build on these previous results, and investigate the consequences of chemokine receptor heteromerization with ChemR23, the receptor of chemerin, a leukocyte chemoattractant protein structurally unrelated to chemokines. We show, using BRET and HTRF assays, that ChemR23 forms homomers, and provide data suggesting that ChemR23 also forms heteromers with the chemokine receptors CCR7 and CXCR4. As previously described for other chemokine receptor heteromers, negative binding cooperativity was detected between ChemR23 and chemokine receptors, i.e. the ligands of one receptor competed for the binding of a specific tracer of the other. We also showed, using mouse bone marrow-derived dendritic cells prepared from wild-type and ChemR23 knockout mice, that ChemR23-specific ligands cross-inhibited CXCL12 binding on CXCR4 in a ChemR23-dependent manner, supporting the relevance of the ChemR23/CXCR4 interaction in native leukocytes. Finally, and in contrast to the situation encountered for other previously characterized CXCR4 heteromers, we showed that the CXCR4-specific antagonist AMD3100 did not cross-inhibit chemerin binding in cells co-expressing ChemR23 and CXCR4, demonstrating that cross-regulation by AMD3100 depends on the nature of receptor partners with which CXCR4 is co-expressed.

Limpieza y desinfección: riesgo toxicológico Cleaning and disinfection: toxicological risk

Directory of Open Access Journals (Sweden)

Sebastián Sánchez-Fortún Rodríguez

2006-12-01

Full Text Available La utilización de biocidas para la desinfección de superficies, como las torres de refrigeración, ha llegado a ser un elemento clave para la prevención de enfermedades, como es el caso de la legionelosis. Pero su utilización conlleva asumir una serie de riesgos, tanto para la Salud Pública como para el entorno medioambiental donde las descargas procedentes de los puntos de aplicación pueden provocar profundas alteraciones en el medio acuático. El análisis efectuado en el presente trabajo, acerca de los diferentes parámetros para la evaluación del riesgo que supone la utilización de estos formulados, lleva a la conclusión de que, aún entendiendo que todo biocida podría provocar efectos no deseados sobre los seres vivos y el medioambiente, un correcto equilibrio entre los criterios de eficacia y seguridad es la única pauta viable para prevenir el riesgo toxicológico generado por las necesarias pautas de limpieza y desinfección de estas superficies.The use of biocides for the surfaces disinfection, as cooling towers, has ended up being a key element for the prevention of illnesses, like it is the case of legionelosis disease. But their use bears to assume risks, as much for the Public and Environmental Health where the discharges can cause deep alterations in the aquatic ecosystems. The analysis apply in this work, about the different parameters for the risk evaluation that supposes the use of these formulated, takes to the conclusion that, still understanding that all biocide could cause adverse effects on organisms and environments, a correct balance among effectiveness and security approaches is the only viable rule to prevent the toxicological risk generated by the necessary cleaning and disinfection rules of these surfaces.

FastChem: An ultra-fast equilibrium chemistry

Science.gov (United States)

Kitzmann, Daniel; Stock, Joachim

2018-04-01

FastChem is an equilibrium chemistry code that calculates the chemical composition of the gas phase for given temperatures and pressures. Written in C++, it is based on a semi-analytic approach, and is optimized for extremely fast and accurate calculations.

The PubChem chemical structure sketcher

Directory of Open Access Journals (Sweden)

Ihlenfeldt Wolf D

2009-12-01

Full Text Available Abstract PubChem is an important public, Web-based information source for chemical and bioactivity information. In order to provide convenient structure search methods on compounds stored in this database, one mandatory component is a Web-based drawing tool for interactive sketching of chemical query structures. Web-enabled chemical structure sketchers are not new, being in existence for years; however, solutions available rely on complex technology like Java applets or platform-dependent plug-ins. Due to general policy and support incident rate considerations, Java-based or platform-specific sketchers cannot be deployed as a part of public NCBI Web services. Our solution: a chemical structure sketching tool based exclusively on CGI server processing, client-side JavaScript functions, and image sequence streaming. The PubChem structure editor does not require the presence of any specific runtime support libraries or browser configurations on the client. It is completely platform-independent and verified to work on all major Web browsers, including older ones without support for Web2.0 JavaScript objects.

ChemProt-2.0: visual navigation in a disease chemical biology database

DEFF Research Database (Denmark)

Kjærulff, Sonny Kim; Wich, Louis; Kringelum, Jens Vindahl

2013-01-01

ChemProt-2.0 (http://www.cbs.dtu.dk/services/ChemProt-2.0) is a public available compilation of multiple chemical-protein annotation resources integrated with diseases and clinical outcomes information. The database has been updated to > 1.15 million compounds with 5.32 millions bioactivity measu...

Exploration of Mars with the ChemCam LIBS Instrument and the Curiosity Rover

Science.gov (United States)

Newsom, Horton E.

2016-01-01

The Mars Science Laboratory (MSL) Curiosity rover landed on Mars in August 2012, and has been exploring the planet ever since. Dr. Horton E. Newsom will discuss the MSL's design and main goal, which is to characterize past environments that may have been conducive to the evolution and sustainability of life. He will also discuss Curiosity's science payload, and remote sensing, analytical capabilities, and direct discoveries of the Chemistry & Camera (ChemCam) instrument, which is the first Laser Induced Breakdown Spectrometer (LIBS) to operate on another planetary surface and determine the chemistry of the rocks and soils.

Aquatic exposures of chemical mixtures in urban environments: Approaches to impact assessment.

Science.gov (United States)

de Zwart, Dick; Adams, William; Galay Burgos, Malyka; Hollender, Juliane; Junghans, Marion; Merrington, Graham; Muir, Derek; Parkerton, Thomas; De Schamphelaere, Karel A C; Whale, Graham; Williams, Richard

2018-03-01

Urban regions of the world are expanding rapidly, placing additional stress on water resources. Urban water bodies serve many purposes, from washing and sources of drinking water to transport and conduits for storm drainage and effluent discharge. These water bodies receive chemical emissions arising from either single or multiple point sources, diffuse sources which can be continuous, intermittent, or seasonal. Thus, aquatic organisms in these water bodies are exposed to temporally and compositionally variable mixtures. We have delineated source-specific signatures of these mixtures for diffuse urban runoff and urban point source exposure scenarios to support risk assessment and management of these mixtures. The first step in a tiered approach to assessing chemical exposure has been developed based on the event mean concentration concept, with chemical concentrations in runoff defined by volumes of water leaving each surface and the chemical exposure mixture profiles for different urban scenarios. Although generalizations can be made about the chemical composition of urban sources and event mean exposure predictions for initial prioritization, such modeling needs to be complemented with biological monitoring data. It is highly unlikely that the current paradigm of routine regulatory chemical monitoring alone will provide a realistic appraisal of urban aquatic chemical mixture exposures. Future consideration is also needed of the role of nonchemical stressors in such highly modified urban water bodies. Environ Toxicol Chem 2018;37:703-714. © 2017 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC. © 2017 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

ConfChem Conference on Flipped Classroom: Reclaiming Face Time--How an Organic Chemistry Flipped Classroom Provided Access to Increased Guided Engagement

Science.gov (United States)

Trogden, Bridget G.

2015-01-01

Students' active engagement is one of the most critical challenges to any successful learning environment. The blending of active engagement along with rich, meaningful content is necessary for chemical educators to re-examine the purpose of the chemistry classroom. The Spring 2014 ConfChem conference, Flipped Classroom, was held from May 9 to…

ChemProt-3.0: a global chemical biology diseases mapping

DEFF Research Database (Denmark)

Kringelum, Jens Vindahl; Kjærulff, Sonny Kim; Brunak, Søren

2016-01-01

ChemProt is a publicly available compilation of chemical-protein-disease annotation resources that enables the study of systems pharmacology for a small molecule across multiple layers of complexity from molecular to clinical levels. In this third version, ChemProt has been updated to more than 1...... properties. In addition, the user has the possibility to search by compound, target, pathway, disease and clinical effect. Genetic variations associated to target proteins were integrated, making it possible to plan pharmacogenetic studies and to suggest human response variability to drug. Finally...

Applying adverse outcome pathways and species sensitivity-weighted distribution to predicted-no-effect concentration derivation and quantitative ecological risk assessment for bisphenol A and 4-nonylphenol in aquatic environments: A case study on Tianjin City, China.

Science.gov (United States)

Wang, Ying; Na, Guangshui; Zong, Humin; Ma, Xindong; Yang, Xianhai; Mu, Jingli; Wang, Lijun; Lin, Zhongsheng; Zhang, Zhifeng; Wang, Juying; Zhao, Jinsong

2018-02-01

Adverse outcome pathways (AOPs) are a novel concept that effectively considers the toxic modes of action and guides the ecological risk assessment of chemicals. To better use toxicity data including biochemical or molecular responses and mechanistic data, we further developed a species sensitivity-weighted distribution (SSWD) method for bisphenol A and 4-nonylphenol. Their aquatic predicted-no-effect concentrations (PNECs) were derived using the log-normal statistical extrapolation method. We calculated aquatic PNECs of bisphenol A and 4-nonylphenol with values of 4.01 and 0.721 µg/L, respectively. The ecological risk of each chemical in different aquatic environments near Tianjin, China, a coastal municipality along the Bohai Sea, was characterized by hazard quotient and probabilistic risk quotient assessment techniques. Hazard quotients of 7.02 and 5.99 at 2 municipal sewage sites using all of the endpoints were observed for 4-nonylphenol, which indicated high ecological risks posed by 4-nonylphenol to aquatic organisms, especially endocrine-disrupting effects. Moreover, a high ecological risk of 4-nonylphenol was indicated based on the probabilistic risk quotient method. The present results show that combining the SSWD method and the AOP concept could better protect aquatic organisms from adverse effects such as endocrine disruption and could decrease uncertainty in ecological risk assessment. Environ Toxicol Chem 2018;37:551-562. © 2017 SETAC. © 2017 SETAC.

I:\\AA-TYPESET\\CHEM\\2005\\Van Es.vp

African Journals Online (AJOL)

NJD

aDepartment of Biochemistry and Microbiology, Cook College, Rutgers The State University of New Jersey, 08903-0231, USA. .... 4 formation is expected to transfer to the more basic nitrogen of ...... Jouannetaud, French Patent (2000). Chem.

Chem systems

International Nuclear Information System (INIS)

Anon.

1992-01-01

This paper reports that world styrene demand, paced by a near doubling of combined requirements in East Asia and Oceania, could reach 19.3 million metric tons by 2000, an average growth rate of 3.7%/year. So concludes Chem Systems Inc., Tarrytown, N.Y., in a study of world styrene markets through the end of the century. Pacific Rim styrene production and consumption throughout the 1990s are predicted to make up increasingly larger shares of world markets, while demand and production lag in the U.S. and western Europe. Demand and capacity in other parts of the world will grow in real terms, increasing combined market shares only slightly. Most of the increase will be driven by demand in East Asia and Oceania, where consumption by century's end is expected to increase 4.48 million metric tons from 2.25 million tons in 1991. Meantime, Japan's styrene demand in 2000 is projected at 2.64 million tons, a 500,000 ton increase from 1991 demand but a net market loss of 1.9%

Effects of chlorpyrifos on life cycle parameters, cytochrome P450S expression, and antioxidant systems in the monogonont rotifer Brachionus koreanus.

Science.gov (United States)

Kim, Ryeo-Ok; Kim, Bo-Mi; Jeong, Chang-Bum; Lee, Jae-Seong; Rhee, Jae-Sung

2016-06-01

Chlorpyrifos is a widely used organophosphorus insecticide for controlling diverse insect pests of crops. In the monogonont rotifer Brachionus koreanus, population growth retardation with the inhibition of lifespan, fecundity, and individual body size of ovigerous females was shown over 10 d in response to chlorpyrifos exposure. At the molecular and biochemical levels, the rotifer B. koreanus defensome, composed of cytochrome P450 complements, heat shock protein 70, and antioxidant enzymatic systems (i.e., glutathione, glutathione peroxidase, glutathione reductase, and glutathione S-transferase), was significantly induced in response to different concentrations of chlorpyrifos. Thus, chlorpyrifos strongly induced a defensome system to mitigate the deleterious effects of chlorpyrifos at in vivo and in vitro levels as a trade-off in fitness costs. Environ Toxicol Chem 2016;35:1449-1457. © 2015 SETAC. © 2015 SETAC.

The effects of epoxiconazole and α-cypermethrin on Daphnia magna growth, reproduction, and offspring size

DEFF Research Database (Denmark)

Gottardi, Michele; Birch, Michala Rosa; Dalhoff, Kristoffer

2017-01-01

of sublethal concentrations of epoxiconazole and α-cypermethrin and their mixture on growth, reproduction, and in vivo cytochrome P450 activity of the aquatic crustacean Daphnia magna over 42 d. Continuous exposure to nonlethal concentrations of α-cypermethrin at 20 ng/L negatively affected adult growth...... and number and size of neonates within the first 14 d of exposure. Exposure to epoxiconazole at 25 μg/L increased protein content of adults within 1 to 3 d after initiating exposure and increased cumulative number of offspring at exposure times >31 d. Epoxiconazole enhanced the negative effect of α...... with other stressors such as food scarcity, predation, and pathogens, posing an additional hazard for the organisms at the beginning of their life cycle. Environ Toxicol Chem 2017;9999:1-12. © 2017 SETAC....

Impaired Auditory and Contextual Fear Conditioning in Soman-Exposed Rats

Science.gov (United States)

2011-01-01

Hymowitz et al., 1985, 1990; Modrow and Jaax, 1989). Pavlovian fear conditioning is a useful procedure often used to elucidate the neural substrates...Stitcher DL, Lennox WJ. Protection against both lethal and behavioral effects of soman. Drug Chem Toxicol 1984;7:605–24. Hasselmo ME. The role of...Rethinking the fear circuit: the central nucleus of the amygdala is required for the acquisition, consolidation, and expression of Pavlovian fear

NutriChem 2.0: exploring the effect of plant-based foods on human health and drug efficacy

DEFF Research Database (Denmark)

Ni, Yueqiong; Jensen, Kasper; Kouskoumvekaki, Eirini

2017-01-01

NutriChem is a database generated by text mining of 21 million MEDLINE abstracts that links plant-based foods with their small molecule components and human health effect. In this new, second release of NutriChem (NutriChem 2.0) we have integrated information on overlapping protein targets between...

Tropospheric ozone using an emission tagging technique in the CAM-Chem and WRF-Chem models

Science.gov (United States)

Lupascu, A.; Coates, J.; Zhu, S.; Butler, T. M.

2017-12-01

Tropospheric ozone is a short-lived climate forcing pollutant. High concentration of ozone can affect human health (cardiorespiratory and increased mortality due to long-term exposure), and also it damages crops. Attributing ozone concentrations to the contributions from different sources would indicate the effects of locally emitted or transported precursors on ozone levels in specific regions. This information could be used as an important component of the design of emissions reduction strategies by indicating which emission sources could be targeted for effective reductions, thus reducing the burden of ozone pollution. Using a "tagging" approach within the CAM-Chem (global) and WRF-Chem (regional) models, we can quantify the contribution of individual emission of NOx and VOC precursors on air quality. Hence, when precursor emissions of NOx are tagged, we have seen that the largest contributors on ozone levels are the anthropogenic sources, while in the case of precursor emissions of VOCs, the biogenic sources and methane account for more than 50% of ozone levels. Further, we have extended the NOx tagging method in order to investigate continental source region contributions to concentrations of ozone over various receptor regions over the globe, with a zoom over Europe. In general, summertime maximum ozone in most receptor regions is largely attributable to local emissions of anthropogenic NOx and biogenic VOC. During the rest of the year, especially during springtime, ozone in most receptor regions shows stronger influences from anthropogenic emissions of NOx and VOC in remote source regions.

Análise farmacológica e toxicológica de dois enantiômeros derivados do monoterpeno citronelal: Uma abordagem in sílico

Directory of Open Access Journals (Sweden)

Cássio Ilan Soares Medeiros

2017-07-01

Full Text Available Os monoterpenos são uma classe de metabolitos secundários de plantas conhecidas por apresentar uma variedade de efeitos em diferentes sistemas biológicos. Portanto, o objetivo deste estudo foi avaliar os efeitos farmacológicos e toxicológicos dos enantiômeros (R-(+- e (S-(--citronelal in sílico. Cerca de 50% das razões que levam à insuficiência no desenvolvimento de um fármaco estão associados com o perfil farmacocinético e toxicológico. Assim, a determinação do perfil farmacocinético (ADME juntamente com a toxicidade (ADMET são parâmetros importantes na definição de biodisponibilidade e efeitos tóxicos de uma molécula. Os softwares Pass online, Osiris e Molinspiration foram utilizados no estudo para atividades in sílico. Modelos in sílico são aplicados para a avaliação da toxicidade de compostos em ambientes metabólicos de mamíferos. Os resultados obtidos mostraram que as moléculas foram semelhantes a fármacos com 29 possíveis atividades com Pa > 70% e estes monoterpenos apresentaram baixo risco de toxicidade teórica.

Calcium Sulfate Characterized by ChemCam/Curiosity at Gale Crater, Mars

Science.gov (United States)

Nachon, M.; Clegg, S. N.; Mangold, N.; Schroeder, S.; Kah, L. C.; Dromart, G.; Ollila, A.; Johnson, J. R.; Oehler, D. Z.; Bridges, J. C.;

Improved Near Real Time WRF-Chem Volcanic Emission Prediction and Impacts of Ash Aerosol on Weather.

Science.gov (United States)

Stuefer, M.; Webley, P. W.; Hirtl, M.

2017-12-01

We use the numerical Weather Research Forecasting (WRF) model with online Chemistry (WRF-Chem) to investigate the regional effects of volcanic aerosol on weather. A lot of observational data have become available since the Icelandic eruption of Eyjafjallajökull in spring 2010. The observed plume characteristics and meteorological data have been exploited for volcanic WRF-Chem case studies. We concluded that the Eyjafjallajökull ash plume resulted in significant direct aerosol effects altering the state of the atmosphere over large parts of Europe. The WRF-Chem model runs show near surface temperature differences up to 3ºC, altered vertical stability, changed pressure- and wind fields within the atmosphere loaded with ash aerosol. The modeled results have been evaluated with lidar network data, and ground and balloon based observations all over Europe. Besides case studies, we use WRF-Chem to build an improved volcanic ash decision support system that NOAA can use within the Volcanic Ash Advisory Center (VAAC) system. Realistic eruption source parameter (ESP) estimates are a main challenge in predicting volcanic emission dispersion in near real time. We implemented historic ESP into the WRF-Chem preprocessing routine, which can be used as a first estimate to assess a volcanic plume once eruption activity is reported. In a second step, a range of varying plume heights has been associated with the different ash variables within WRF-Chem, resulting in an assembly of different plume scenarios within one WRF-Chem model run. Once there is plume information available from ground or satellite observations, the forecaster has the option to select the corresponding ash variable that best matches the observations. In addition we added an automatic domain generation tool to create near real time WRF-Chem model runs anywhere on the globe by reducing computing expenses at the same time.

ChemCalc: a building block for tomorrow's chemical infrastructure.

Science.gov (United States)

Patiny, Luc; Borel, Alain

2013-05-24

Web services, as an aspect of cloud computing, are becoming an important part of the general IT infrastructure, and scientific computing is no exception to this trend. We propose a simple approach to develop chemical Web services, through which servers could expose the essential data manipulation functionality that students and researchers need for chemical calculations. These services return their results as JSON (JavaScript Object Notation) objects, which facilitates their use for Web applications. The ChemCalc project http://www.chemcalc.org demonstrates this approach: we present three Web services related with mass spectrometry, namely isotopic distribution simulation, peptide fragmentation simulation, and molecular formula determination. We also developed a complete Web application based on these three Web services, taking advantage of modern HTML5 and JavaScript libraries (ChemDoodle and jQuery).

ChemCam on MSL 2009: first laser induced breakdown spectrometer for space science

Energy Technology Data Exchange (ETDEWEB)

Wiens, Roger C [Los Alamos National Laboratory

2008-01-01

ChemCam is one of the 10 instrument suites on the Mars Science Laboratory, a martian rover being built by Jet Propulsion Laboratory, for the next NASA mission to Mars (MSL 2009). ChemCam is an instrument package consisting of two remote sensing instruments: a Laser-Induced Breakdown Spectrometer (LIBS) and a Remote Micro-Imager (RMI). LIBS provides elemental compositions of rocks and soils, while the RMI places the LIBS analyses in their geomorphologic context. Both instruments rely on an autofocus capability to precisely focus on the chosen target, located at distances from the rover comprised between 1 and 9 m for LIBS, and 2 m and infinity for RMI. ChemCam will help determine which samples, within the vicinity of the MSL rover, are of sufficient interest to use the contact and in-situ instruments for further characterization. It will provide valuable analyses of samples that are inaccessible to contact and in-situ instruments, and of a much larger number of samples than can be done with this kind of instrument. ChemCam also has a capability to provide passive spectroscopy data of rocks and soils on Mars. ChemCam hardware consists of a Mast Unit (MU), provided by France, and a Body Unit (BU) built and tested in the USA. The Flight Model of the MU is assembled, tested and now available in the USA, while the BU is currently being assembled and tested. Both will be connected by the end of year '08 for end-to-end functional and performance tests, before delivery to JPL and assembly on the MSL rover. Launch is scheduled for October 09. After describing the concept of ChemCam, this presentation focuses on its French part, Mast Unit. The results presented show that Mast Unit is able to generate a plasma and collect its light, over the full applicable ranges of distances and temperatures on Mars.

Soil Diversity and Hydration as Observed by ChemCam at Gale Crater, Mars

Science.gov (United States)

Meslin, P.-Y.; Gasnault, O.; Forni, O.; Schröder, S.; Cousin, A.; Berger, G.; Clegg, S. M.; Lasue, J.; Maurice, S.; Sautter, V.; Le Mouélic, S.; Wiens, R. C.; Fabre, C.; Goetz, W.; Bish, D.; Mangold, N.; Ehlmann, B.; Lanza, N.; Harri, A.-M.; Anderson, R.; Rampe, E.; McConnochie, T. H.; Pinet, P.; Blaney, D.; Léveillé, R.; Archer, D.; Barraclough, B.; Bender, S.; Blake, D.; Blank, J. G.; Bridges, N.; Clark, B. C.; DeFlores, L.; Delapp, D.; Dromart, G.; Dyar, M. D.; Fisk, M.; Gondet, B.; Grotzinger, J.; Herkenhoff, K.; Johnson, J.; Lacour, J.-L.; Langevin, Y.; Leshin, L.; Lewin, E.; Madsen, M. B.; Melikechi, N.; Mezzacappa, A.; Mischna, M. A.; Moores, J. E.; Newsom, H.; Ollila, A.; Perez, R.; Renno, N.; Sirven, J.-B.; Tokar, R.; de la Torre, M.; d'Uston, L.; Vaniman, D.; Yingst, A.; Kemppinen, Osku; Minitti, Michelle; Cremers, David; Bell, James F.; Edgar, Lauren; Farmer, Jack; Godber, Austin; Wadhwa, Meenakshi; Wellington, Danika; McEwan, Ian; Newman, Claire; Richardson, Mark; Charpentier, Antoine; Peret, Laurent; King, Penelope; Weigle, Gerald; Schmidt, Mariek; Li, Shuai; Milliken, Ralph; Robertson, Kevin; Sun, Vivian; Baker, Michael; Edwards, Christopher; Farley, Kenneth; Griffes, Jennifer; Miller, Hayden; Newcombe, Megan; Pilorget, Cedric; Rice, Melissa; Siebach, Kirsten; Stack, Katie; Stolper, Edward; Brunet, Claude; Hipkin, Victoria; Marchand, Geneviève; Sánchez, Pablo Sobrón; Favot, Laurent; Cody, George; Steele, Andrew; Flückiger, Lorenzo; Lees, David; Nefian, Ara; Martin, Mildred; Gailhanou, Marc; Westall, Frances; Israël, Guy; Agard, Christophe; Baroukh, Julien; Donny, Christophe; Gaboriaud, Alain; Guillemot, Philippe; Lafaille, Vivian; Lorigny, Eric; Paillet, Alexis; Pérez, René; Saccoccio, Muriel; Yana, Charles; Armiens-Aparicio, Carlos; Rodríguez, Javier Caride; Blázquez, Isaías Carrasco; Gómez, Felipe Gómez; Gómez-Elvira, Javier; Hettrich, Sebastian; Malvitte, Alain Lepinette; Jiménez, Mercedes Marín; Martínez-Frías, Jesús; Martín-Soler, Javier; Martín-Torres, F. Javier; Jurado, Antonio Molina; Mora-Sotomayor, Luis; Caro, Guillermo Muñoz; López, Sara Navarro; Peinado-González, Verónica; Pla-García, Jorge; Manfredi, José Antonio Rodriguez; Romeral-Planelló, Julio José; Fuentes, Sara Alejandra Sans; Martinez, Eduardo Sebastian; Redondo, Josefina Torres; Urqui-O'Callaghan, Roser; Mier, María-Paz Zorzano; Chipera, Steve; Mauchien, Patrick; Manning, Heidi; Fairén, Alberto; Hayes, Alexander; Joseph, Jonathan; Squyres, Steven; Sullivan, Robert; Thomas, Peter; Dupont, Audrey; Lundberg, Angela; DeMarines, Julia; Grinspoon, David; Reitz, Günther; Prats, Benito; Atlaskin, Evgeny; Genzer, Maria; Haukka, Harri; Kahanpää, Henrik; Kauhanen, Janne; Kemppinen, Osku; Paton, Mark; Polkko, Jouni; Schmidt, Walter; Siili, Tero; Wray, James; Wilhelm, Mary Beth; Poitrasson, Franck; Patel, Kiran; Gorevan, Stephen; Indyk, Stephen; Paulsen, Gale; Gupta, Sanjeev; Schieber, Juergen; Geffroy, Claude; Baratoux, David; Cros, Alain; Lee, Qiu-Mei; Pallier, Etienne; Parot, Yann; Toplis, Mike; Brunner, Will; Heydari, Ezat; Achilles, Cherie; Oehler, Dorothy; Sutter, Brad; Cabane, Michel; Coscia, David; Israël, Guy; Szopa, Cyril; Robert, François; Nachon, Marion; Buch, Arnaud; Stalport, Fabien; Coll, Patrice; François, Pascaline; Raulin, François; Teinturier, Samuel; Cameron, James; Dingler, Robert; Jackson, Ryan Steele; Johnstone, Stephen; Little, Cynthia; Nelson, Tony; Williams, Richard B.; Jones, Andrea; Kirkland, Laurel; Treiman, Allan; Baker, Burt; Cantor, Bruce; Caplinger, Michael; Davis, Scott; Duston, Brian; Edgett, Kenneth; Fay, Donald; Hardgrove, Craig; Harker, David; Herrera, Paul; Jensen, Elsa; Kennedy, Megan R.; Krezoski, Gillian; Krysak, Daniel; Lipkaman, Leslie; Malin, Michael; McCartney, Elaina; McNair, Sean; Nixon, Brian; Posiolova, Liliya; Ravine, Michael; Salamon, Andrew; Saper, Lee; Stoiber, Kevin; Supulver, Kimberley; Van Beek, Jason; Van Beek, Tessa; Zimdar, Robert; French, Katherine Louise; Iagnemma, Karl; Miller, Kristen; Summons, Roger; Goesmann, Fred; Hviid, Stubbe; Johnson, Micah; Lefavor, Matthew; Lyness, Eric; Breves, Elly; Fassett, Caleb; Bristow, Thomas; DesMarais, David; Edwards, Laurence; Haberle, Robert; Hoehler, Tori; Hollingsworth, Jeff; Kahre, Melinda; Keely, Leslie; McKay, Christopher; Wilhelm, Mary Beth; Bleacher, Lora; Brinckerhoff, William; Choi, David; Conrad, Pamela; Dworkin, Jason P.; Eigenbrode, Jennifer; Floyd, Melissa; Freissinet, Caroline; Garvin, James; Glavin, Daniel; Harpold, Daniel; Jones, Andrea; Mahaffy, Paul; Martin, David K.; McAdam, Amy; Pavlov, Alexander; Raaen, Eric; Smith, Michael D.; Stern, Jennifer; Tan, Florence; Trainer, Melissa; Meyer, Michael; Posner, Arik; Voytek, Mary; Anderson, Robert C.; Aubrey, Andrew; Beegle, Luther W.; Behar, Alberto; Brinza, David; Calef, Fred; Christensen, Lance; Crisp, Joy A.; Feldman, Jason; Feldman, Sabrina; Flesch, Gregory; Hurowitz, Joel; Jun, Insoo; Keymeulen, Didier; Maki, Justin; Morookian, John Michael; Parker, Timothy; Pavri, Betina; Schoppers, Marcel; Sengstacken, Aaron; Simmonds, John J.; Spanovich, Nicole; Vasavada, Ashwin R.; Webster, Christopher R.; Yen, Albert; Cucinotta, Francis; Jones, John H.; Ming, Douglas; Morris, Richard V.; Niles, Paul; Nolan, Thomas; Radziemski, Leon; Berman, Daniel; Dobrea, Eldar Noe; Williams, Rebecca M. E.; Lewis, Kevin; Cleghorn, Timothy; Huntress, Wesley; Manhès, Gérard; Hudgins, Judy; Olson, Timothy; Stewart, Noel; Sarrazin, Philippe; Grant, John; Vicenzi, Edward; Wilson, Sharon A.; Bullock, Mark; Ehresmann, Bent; Hamilton, Victoria; Hassler, Donald; Peterson, Joseph; Rafkin, Scot; Zeitlin, Cary; Fedosov, Fedor; Golovin, Dmitry; Karpushkina, Natalya; Kozyrev, Alexander; Litvak, Maxim; Malakhov, Alexey; Mitrofanov, Igor; Mokrousov, Maxim; Nikiforov, Sergey; Prokhorov, Vasily; Sanin, Anton; Tretyakov, Vladislav; Varenikov, Alexey; Vostrukhin, Andrey; Kuzmin, Ruslan; Wolff, Michael; McLennan, Scott; Botta, Oliver; Drake, Darrell; Bean, Keri; Lemmon, Mark; Schwenzer, Susanne P.; Lee, Ella Mae; Sucharski, Robert; Hernández, Miguel Ángel de Pablo; Ávalos, Juan José Blanco; Ramos, Miguel; Kim, Myung-Hee; Malespin, Charles; Plante, Ianik; Muller, Jan-Peter; Navarro-González, Rafael; Ewing, Ryan; Boynton, William; Downs, Robert; Fitzgibbon, Mike; Harshman, Karl; Morrison, Shaunna; Dietrich, William; Kortmann, Onno; Palucis, Marisa; Sumner, Dawn Y.; Williams, Amy; Lugmair, Günter; Wilson, Michael A.; Rubin, David; Jakosky, Bruce; Balic-Zunic, Tonci; Frydenvang, Jens; Jensen, Jaqueline Kløvgaard; Kinch, Kjartan; Koefoed, Asmus; Stipp, Susan Louise Svane; Boyd, Nick; Campbell, John L.; Gellert, Ralf; Perrett, Glynis; Pradler, Irina; VanBommel, Scott; Jacob, Samantha; Owen, Tobias; Rowland, Scott; Atlaskin, Evgeny; Savijärvi, Hannu; Boehm, Eckart; Böttcher, Stephan; Burmeister, Sönke; Guo, Jingnan; Köhler, Jan; García, César Martín; Mueller-Mellin, Reinhold; Wimmer-Schweingruber, Robert; Bridges, John C.; Benna, Mehdi; Franz, Heather; Bower, Hannah; Brunner, Anna; Blau, Hannah; Boucher, Thomas; Carmosino, Marco; Atreya, Sushil; Elliott, Harvey; Halleaux, Douglas; Rennó, Nilton; Wong, Michael; Pepin, Robert; Elliott, Beverley; Spray, John; Thompson, Lucy; Gordon, Suzanne; Williams, Joshua; Vasconcelos, Paulo; Bentz, Jennifer; Nealson, Kenneth; Popa, Radu; Kah, Linda C.; Moersch, Jeffrey; Tate, Christopher; Day, Mackenzie; Kocurek, Gary; Hallet, Bernard; Sletten, Ronald; Francis, Raymond; McCullough, Emily; Cloutis, Ed; ten Kate, Inge Loes; Kuzmin, Ruslan; Arvidson, Raymond; Fraeman, Abigail; Scholes, Daniel; Slavney, Susan; Stein, Thomas; Ward, Jennifer; Berger, Jeffrey

2013-09-01

The ChemCam instrument, which provides insight into martian soil chemistry at the submillimeter scale, identified two principal soil types along the Curiosity rover traverse: a fine-grained mafic type and a locally derived, coarse-grained felsic type. The mafic soil component is representative of widespread martian soils and is similar in composition to the martian dust. It possesses a ubiquitous hydrogen signature in ChemCam spectra, corresponding to the hydration of the amorphous phases found in the soil by the CheMin instrument. This hydration likely accounts for an important fraction of the global hydration of the surface seen by previous orbital measurements. ChemCam analyses did not reveal any significant exchange of water vapor between the regolith and the atmosphere. These observations provide constraints on the nature of the amorphous phases and their hydration.

Soil diversity and hydration as observed by ChemCam at Gale crater, Mars

Science.gov (United States)

Meslin, P.-Y.; Gasnault, O.; Forni, O.; Schroder, S.; Cousin, A.; Berger, G.; Clegg, S.M.; Lasue, J.; Maurice, S.; Sautter, V.; Le Mouélic, S.; Wiens, R.C.; Fabre, C.; Goetz, W.; Bish, D.L.; Mangold, N.; Ehlmann, B.; Lanza, N.; Harri, A.-M.; Anderson, Ryan Bradley; Rampe, E.; McConnochie, T.H.; Pinet, P.; Blaney, D.; ,; Archer, D.; Barraclough, B.; Bender, S.; Blake, D.; Blank, J.G.; Bridges, N.; Clark, B. C.; DeFlores, L.; Delapp, D.; Dromart, G.; Dyar, M.D.; Fisk, M. R.; Gondet, B.; Grotzinger, J.; Herkenhoff, K.; Johnson, J.; Lacour, J.-L.; Langevin, Y.; Leshin, L.; Lewin, E.; Madsen, M.B.; Melikechi, N.; Mezzacappa, Alissa; Mischna, M.A.; Moores, J.E.; Newsom, H.; Ollila, A.; ,; Renno, N.; Sirven, J.B.; Tokar, R.; de la Torre, M.; d'Uston, L.; Vaniman, D.; Yingst, A.

2013-01-01

The ChemCam instrument, which provides insight into martian soil chemistry at the submillimeter scale, identified two principal soil types along the Curiosity rover traverse: a fine-grained mafic type and a locally derived, coarse-grained felsic type. The mafic soil component is representative of widespread martian soils and is similar in composition to the martian dust. It possesses a ubiquitous hydrogen signature in ChemCam spectra, corresponding to the hydration of the amorphous phases found in the soil by the CheMin instrument. This hydration likely accounts for an important fraction of the global hydration of the surface seen by previous orbital measurements. ChemCam analyses did not reveal any significant exchange of water vapor between the regolith and the atmosphere. These observations provide constraints on the nature of the amorphous phases and their hydration.

Sulfur Geochemical Analysis and Interpretation with ChemCam on the Curiosity Rover

Science.gov (United States)

Clegg, S. M.; Anderson, R. B.; Frydenvang, J.; Forni, O.; Newsom, H. E.; Blaney, D. L.; Maurice, S.; Wiens, R. C.

2017-12-01

The Curiosity rover has encountered many forms of sulfur including calcium sulfate veins [1], hydrated Mg sulfates, and Fe sulfates along the traverse through Gale crater. A new SO3 calibration model for the remote Laser-Induced Breakdown Spectroscopy (LIBS) technique used by the ChemCam instrument enables improved quantitative analysis of SO3, which has not been previously reported by ChemCam on a routine or quantitative basis. In this paper, the details of this new LIBS calibration model will be described and applied to many disparate Mars targets. Among them, Mavor contains a calcium sulfate vein surrounded by bedrock. In contrast, Jake M. is a float rock, Wernecke is a bedrock, Cumberland and Windjana are drill targets. In 2015 the ChemCam instrument team completed a re-calibration of major elements based on a significantly expanded set of >500 geochemical standards using the ChemCam testbed at Los Alamos National Laboratory [2]. In addition to these standards, the SO3 compositional range was recently extended with a series of doped samples containing various mixtures of Ca- and Mg-sulfate with basalt BHVO2. Spectra from these standards were processed per [4]. Calibration and Mars spectra were converted to peak-area-summed LIBS spectra that enables the SO3 calibration. These peak-area spectra were used to generate three overlapping partial least squares (PLS1) calibration sub-models as described by Anderson et al. [3, 5]. ChemCam analysis of Mavor involved a 3x3 raster in which locations 5 and 6 primarily probed Ca-sulfate material. The new ChemCam SO3 compositions for Mavor 5 and Mavor 6 are 48.6±1.2 and 50.3±1.2 wt% SO3, respectively. The LIBS spectra also recorded the presence of other elements that are likely responsible for the departure from pure Ca-sulfate chemistry. On the low-abundance side, the remaining 7 Mavor locations, Jake M., Cumberland, Windjana, and Wernecke all contain much lower SO3, between 1.4±0.5 wt% and 2.3±0.3 wt% SO3. [1] Nachon et

ChemANDTM - a system health monitor for plant chemistry

International Nuclear Information System (INIS)

Turner, C.W.; Mitchel, G.R.; Balakrishnan, P.V.; Tosello, G.

1999-07-01

Effective management of plant systems throughout their lifetime requires much more than data acquisition and display - it requires that the plant's system health be continually monitored and managed. AECL has developed a System Health Monitor called ChemAND for CANDU plant chemistry. ChemAND, a Chemistry ANalysis and Diagnostic system, monitors key chemistry parameters in the heat transport system, moderator-cover gas, annulus gas, and the steam cycle during full-power operation and feeds these parameters to models that calculate the effect of current plant operating conditions on the present and future health of the system. Chemistry data from each of the systems are extracted on a regular basis from the plant's Historical Data Server and are sorted according to function, e.g., indicators for condenser in-leakage, air in-leakage, heavy water leakage into the annulus gas, fuel failure, etc. Each parameter is conveniently displayed and is trended along with its alarm limits. ChemAND currently has two analytical models developed for the balance-of-plant. CHEMSOLV calculates crevice chemistry conditions in the steam generator (SG) from either the SG blowdown chemistry conditions or from a simulated condenser leak. This information will be used by operations personnel to evaluate the potential for SG tube corrosion in the crevice region. CHEMSOLV also calculates chemistry conditions throughout the steam-cycle system, as determined by the transport of volatile species such as ammonia, hydrazine, morpholine, and oxygen. A second model, SLUDGE, calculates the deposit loading in the SG as a function of time, based on concentrations of corrosion product in the final feedwater and plant operating conditions. Operations personnel can use this information to predict where to inspect and when to clean. In a future development, SLUDGE will track deposit loading arising from start-up crud bursts and will be used in conjunction with the thermohydraulics code, THIRST, to predict

OrChem - An open source chemistry search engine for Oracle®

Science.gov (United States)

2009-01-01

Background Registration, indexing and searching of chemical structures in relational databases is one of the core areas of cheminformatics. However, little detail has been published on the inner workings of search engines and their development has been mostly closed-source. We decided to develop an open source chemistry extension for Oracle, the de facto database platform in the commercial world. Results Here we present OrChem, an extension for the Oracle 11G database that adds registration and indexing of chemical structures to support fast substructure and similarity searching. The cheminformatics functionality is provided by the Chemistry Development Kit. OrChem provides similarity searching with response times in the order of seconds for databases with millions of compounds, depending on a given similarity cut-off. For substructure searching, it can make use of multiple processor cores on today's powerful database servers to provide fast response times in equally large data sets. Availability OrChem is free software and can be redistributed and/or modified under the terms of the GNU Lesser General Public License as published by the Free Software Foundation. All software is available via http://orchem.sourceforge.net. PMID:20298521

OrChem - An open source chemistry search engine for Oracle(R).

Science.gov (United States)

Rijnbeek, Mark; Steinbeck, Christoph

2009-10-22

Registration, indexing and searching of chemical structures in relational databases is one of the core areas of cheminformatics. However, little detail has been published on the inner workings of search engines and their development has been mostly closed-source. We decided to develop an open source chemistry extension for Oracle, the de facto database platform in the commercial world. Here we present OrChem, an extension for the Oracle 11G database that adds registration and indexing of chemical structures to support fast substructure and similarity searching. The cheminformatics functionality is provided by the Chemistry Development Kit. OrChem provides similarity searching with response times in the order of seconds for databases with millions of compounds, depending on a given similarity cut-off. For substructure searching, it can make use of multiple processor cores on today's powerful database servers to provide fast response times in equally large data sets. OrChem is free software and can be redistributed and/or modified under the terms of the GNU Lesser General Public License as published by the Free Software Foundation. All software is available via http://orchem.sourceforge.net.

Review of emerging contaminants in aquatic biota from Latin America: 2002-2016.

Science.gov (United States)

Llorca, Marta; Farré, Marinella; Eljarrat, Ethel; Díaz-Cruz, Sílvia; Rodríguez-Mozaz, Sara; Wunderlin, Daniel; Barcelo, Damià

2017-07-01

Although it is known that emerging contaminants are widespread all over the globe, there is a gap of information about their distribution in some geographical areas, such as Latin America. The present bibliographic work reviews the available literature about the presence of organic emerging contaminants in Latin American freshwater and marine biota between 2002 and 2016 and includes 23 works from Argentina, Brazil, Chile, Colombia, Mexico, and Nicaragua. In particular, the present review provides an overview of the occurrence of continuously present contaminants such as pharmaceuticals, personal care products, and pyrethroid insecticides, as well as the new groups of persistent organic pollutants, the halogenated flame retardants and the perfluoroalkyl substances. A wide overview is provided, considering not only occurrence data but also effects and potential transfer through the food chain. Environ Toxicol Chem 2017;36:1716-1727. © 2016 SETAC. © 2016 SETAC.

CASSINI S MIMI CHEMS SENSOR CALIBRATED DATA V1.0

Data.gov (United States)

National Aeronautics and Space Administration — The Cassini Magnetospheric Imaging Instrument(MIMI) Charge Energy Mass Spectrometer (CHEMS) contains a deflection system and an overall field of view of 159 x 4 deg....

Data mining a small molecule drug screening representative subset from NIH PubChem.

Science.gov (United States)

Xie, Xiang-Qun; Chen, Jian-Zhong

2008-03-01

PubChem is a scientific showcase of the NIH Roadmap Initiatives. It is a compound repository created to facilitate information exchange and data sharing among the NIH Roadmap-funded Molecular Library Screening Center Network (MLSCN) and the scientific community. However, PubChem has more than 10 million records of compound information. It will be challenging to conduct a drug screening of the whole database of millions of compounds. Thus, the purpose of the present study was to develop a data mining cheminformatics approach in order to construct a representative and structure-diverse sublibrary from the large PubChem database. In this study, a new chemical diverse representative subset, rePubChem, was selected by whole-molecule chemistry-space matrix calculation using the cell-based partition algorithm. The representative subset was generated and was then subjected to evaluations by compound property analyses based on 1D and 2D molecular descriptors. The new subset was also examined and assessed for self-similarity analysis based on 2D molecular fingerprints in comparing with the source compound library. The new subset has a much smaller library size (540K compounds) with minimum similarity and redundancy without loss of the structural diversity and basic molecular properties of its parent library (5.3 million compounds). The new representative subset library generated could be a valuable structure-diverse compound resource for in silico virtual screening and in vitro HTS drug screening. In addition, the established subset generation method of using the combined cell-based chemistry-space partition metrics with pairwised 2D fingerprint-based similarity search approaches will also be important to a broad scientific community interested in acquiring structurally diverse compounds for efficient drug screening, building representative virtual combinatorial chemistry libraries for syntheses, and data mining large compound databases like the PubChem library in general.

Measuring Single-Domain Antibody Interactions with Epitopes in Jet Fuel Using Microscale Thermophoresis

Science.gov (United States)

2015-01-01

hearing loss in rats. J. Toxicol. Environ. Health A. 75(5): 299–317. Itah, A. Y., A. A. Brooks, B. O. Ogar, and A. B. Okure. 2009. Biodegradation of...international jet A-1 aviation fuel by microorganisms isolated from aircraft tank and joint hydrant storage systems. Bull. Environ. Contam. Toxicol. 83(3

The Chemical Aquatic Fate and Effects database (CAFE), a tool that supports assessments of chemical spills in aquatic environments.

Science.gov (United States)

Bejarano, Adriana C; Farr, James K; Jenne, Polly; Chu, Valerie; Hielscher, Al

2016-06-01

The Chemical Aquatic Fate and Effects (CAFE) database is a centralized repository that allows for rapid and unrestricted access to data. Information in CAFE is integrated into a user-friendly tool with modules containing fate and effects data for 32 377 and 4498 chemicals, respectively. Toxicity data are summarized in the form of species sensitivity distributions (SSDs) with associated 1st and 5th percentile hazard concentrations (HCs). An assessment of data availability relative to reported chemical incidents showed that CAFE had fate and toxicity data for 32 and 20 chemicals, respectively, of 55 chemicals reported in the US National Response Center database (2000-2014), and fate and toxicity data for 86 and 103, respectively, of 205 chemicals reported by the National Oceanic and Atmospheric Administration (2003-2014). Modeled environmental concentrations of 2 hypothetical spills (acrylonitrile, 625 barrels; and denatured ethanol, 857 barrels) were used to demonstrate CAFE's practical application. Most species in the 24-h SSD could be potentially impacted by acrylonitrile and denatured ethanol during the first 35 min and 15 h post spill, respectively, with concentrations falling below their HC5s (17 mg/L and 2676 mg/L) at 45 min and 60 h post spill, respectively. Comparisons of CAFE-based versus published HC5 values for 100 chemicals showed that nearly half of values were within a 2-fold difference, with a relatively small number of comparisons exceeding a 10-fold difference. The development of CAFE facilitates access to relevant environmental information, with potential uses likely expanding beyond those related to assessment of spills in aquatic environments. Environ Toxicol Chem 2016;35:1576-1586. © 2015 SETAC. © 2015 SETAC.

Development and Performance of the Modularized, High-performance Computing and Hybrid-architecture Capable GEOS-Chem Chemical Transport Model

Science.gov (United States)

Long, M. S.; Yantosca, R.; Nielsen, J.; Linford, J. C.; Keller, C. A.; Payer Sulprizio, M.; Jacob, D. J.

2014-12-01

The GEOS-Chem global chemical transport model (CTM), used by a large atmospheric chemistry research community, has been reengineered to serve as a platform for a range of computational atmospheric chemistry science foci and applications. Development included modularization for coupling to general circulation and Earth system models (ESMs) and the adoption of co-processor capable atmospheric chemistry solvers. This was done using an Earth System Modeling Framework (ESMF) interface that operates independently of GEOS-Chem scientific code to permit seamless transition from the GEOS-Chem stand-alone serial CTM to deployment as a coupled ESM module. In this manner, the continual stream of updates contributed by the CTM user community is automatically available for broader applications, which remain state-of-science and directly referenceable to the latest version of the standard GEOS-Chem CTM. These developments are now available as part of the standard version of the GEOS-Chem CTM. The system has been implemented as an atmospheric chemistry module within the NASA GEOS-5 ESM. The coupled GEOS-5/GEOS-Chem system was tested for weak and strong scalability and performance with a tropospheric oxidant-aerosol simulation. Results confirm that the GEOS-Chem chemical operator scales efficiently for any number of processes. Although inclusion of atmospheric chemistry in ESMs is computationally expensive, the excellent scalability of the chemical operator means that the relative cost goes down with increasing number of processes, making fine-scale resolution simulations possible.

NutriChem: a systems chemical biology resource to explore the medicinal value of plant-based foods

DEFF Research Database (Denmark)

Jensen, Kasper; Panagiotou, Gianni; Kouskoumvekaki, Irene

2015-01-01

million MEDLINE abstracts for information thatlinks plant-based foods with their small moleculecomponents and human disease phenotypes. Nu-triChem contains text-mined data for 18478 pairs of1772 plant-based foods and 7898 phytochemicals,and 6242 pairs of 1066 plant-based foods and 751diseases. In addition......,there is currently no exhaustive resource on thehealth benefits associated to specific dietary inter-ventions, or a resource covering the broad molecu-lar content of food. Here we present the first releaseof NutriChem, available athttp://cbs.dtu.dk/services/NutriChem-1.0, a database generated by text miningof 21...

New developments on ChemCam laser transmitter and potential applications for other planetology programs

Science.gov (United States)

Faure, Benoît; Durand, Eric; Maurice, Sylvestre; Bruneau, Didier; Montmessin, Franck

2017-11-01

ChemCam is a LIBS Instrument mounted on the MSL 2011 NASA mission. The laser transmitter of this Instrument has been developed by the French society Thales Optronique (former Thales Laser) with a strong technical support from CNES. The paper will first rapidly present the performance of this laser and will then describe the postChemCam developments realized on and around this laser for new planetology programs.

A CNES remote operations center for the MSL ChemCam instrument

Energy Technology Data Exchange (ETDEWEB)

Wiens, Roger C [Los Alamos National Laboratory; Lafaille, Vivian [CNES; Lorgny, Eric [CNES; Baroukh, Julien [CNES; Gaboriaud, Alain [CNES; Saccoccio, Muriel [CNES; Perez, Rene [CNES; Gasnault, Olivier [CNRS/CESR; Maurice, Sylvestre [CNRS/CESR; Blaney, Diana [JPL

2010-01-01

For the first time, a CNES remote operations center in Toulouse will be involved in the tactical operations of a Martian rover in order to operate the ChemCam science instrument in the framework of the NASA MSL (Mars Science Laboratory) mission in 2012. CNES/CESR and LANL have developed and delivered to JPL the ChemCam (Chemistry Camera) instrument located on the top of mast and in the body of the rover. This instrument incorporates a Laser-Induced Breakdown Spectrometer (LIBS) and a Remote Micro-Imager (RMI) for determining elemental compositions of rock targets or soil samples at remote distances from the rover (2-7 m). An agreement has been achieved for operating ChemCam, alternatively, from Toulouse (FR) and Los Alamos (NM, USA), through the JPL ground data system in Pasadena (CA, USA) for a complete Martian year (2 years on Earth). After a brief overview of the MSL mission, this paper presents the instrument, the mission operational system and JPL organization requirements for the scientific investigators (PI and Co-Is). This paper emphasizes innovations applied on the ground segment components and on the operational approach to satisfy the requirements and constraints due to these shared and distributed operations over the world.

Resumen de la tesis doctoral "Efectos toxicológicos de plaguicidas organofosforados y organoclorados sobre camarones del género Penaeus sp en Sinaloa, México".

OpenAIRE

Osuna Flores, Isabel; Galindo Reyes, José Guillermo; Riva Juan, Mª del Carmen

1998-01-01

El presente trabajo tiene como objetivo ampliar los conocimientos sobre la presencia, la toxicidad y los efectos que puedan tener los plaguicidas organofosforados y organoclorados en la Bahía de Ohuira, Topolobampo, Sinaloa, Mexico. Para ello se ha realizado el análisis de residuos de dichos plaguicidas, en agua superficial, sedimento y camarones del género Penaeus sp. Se han realizado tratamientos agudos y subagudos con dichos compuestos y se han evaluado los efectos toxicológicos a travé...

CHEM2D-OPP: A new linearized gas-phase ozone photochemistry parameterization for high-altitude NWP and climate models

Directory of Open Access Journals (Sweden)

J. P. McCormack

2006-01-01

Full Text Available The new CHEM2D-Ozone Photochemistry Parameterization (CHEM2D-OPP for high-altitude numerical weather prediction (NWP systems and climate models specifies the net ozone photochemical tendency and its sensitivity to changes in ozone mixing ratio, temperature and overhead ozone column based on calculations from the CHEM2D interactive middle atmospheric photochemical transport model. We evaluate CHEM2D-OPP performance using both short-term (6-day and long-term (1-year stratospheric ozone simulations with the prototype high-altitude NOGAPS-ALPHA forecast model. An inter-comparison of NOGAPS-ALPHA 6-day ozone hindcasts for 7 February 2005 with ozone photochemistry parameterizations currently used in operational NWP systems shows that CHEM2D-OPP yields the best overall agreement with both individual Aura Microwave Limb Sounder ozone profile measurements and independent hemispheric (10°–90° N ozone analysis fields. A 1-year free-running NOGAPS-ALPHA simulation using CHEM2D-OPP produces a realistic seasonal cycle in zonal mean ozone throughout the stratosphere. We find that the combination of a model cold temperature bias at high latitudes in winter and a warm bias in the CHEM2D-OPP temperature climatology can degrade the performance of the linearized ozone photochemistry parameterization over seasonal time scales despite the fact that the parameterized temperature dependence is weak in these regions.

ChemNet: A Transferable and Generalizable Deep Neural Network for Small-Molecule Property Prediction

Energy Technology Data Exchange (ETDEWEB)

Goh, Garrett B.; Siegel, Charles M.; Vishnu, Abhinav; Hodas, Nathan O.

2017-12-08

With access to large datasets, deep neural networks through representation learning have been able to identify patterns from raw data, achieving human-level accuracy in image and speech recognition tasks. However, in chemistry, availability of large standardized and labelled datasets is scarce, and with a multitude of chemical properties of interest, chemical data is inherently small and fragmented. In this work, we explore transfer learning techniques in conjunction with the existing Chemception CNN model, to create a transferable and generalizable deep neural network for small-molecule property prediction. Our latest model, ChemNet learns in a semi-supervised manner from inexpensive labels computed from the ChEMBL database. When fine-tuned to the Tox21, HIV and FreeSolv dataset, which are 3 separate chemical tasks that ChemNet was not originally trained on, we demonstrate that ChemNet exceeds the performance of existing Chemception models, contemporary MLP models that trains on molecular fingerprints, and it matches the performance of the ConvGraph algorithm, the current state-of-the-art. Furthermore, as ChemNet has been pre-trained on a large diverse chemical database, it can be used as a universal “plug-and-play” deep neural network, which accelerates the deployment of deep neural networks for the prediction of novel small-molecule chemical properties.

Automation and semantics: the CombeChem experience

OpenAIRE

Frey, Jeremy G.

2004-01-01

Some of the experiences of the CombeChem e-Science project in relation to both automation and the need for semantics in combining modern computer science techniques and chemistry are discussed. In particular the aspects of the smart laboratory, large scale data handling and the way this impacts on the necessary database technology are discussed. In addition some of the ways in which the grid can enable greater user interaction with services such as the National Crystallography Service and imp...

Benchmarking Ligand-Based Virtual High-Throughput Screening with the PubChem Database

Directory of Open Access Journals (Sweden)

Mariusz Butkiewicz

2013-01-01

Full Text Available With the rapidly increasing availability of High-Throughput Screening (HTS data in the public domain, such as the PubChem database, methods for ligand-based computer-aided drug discovery (LB-CADD have the potential to accelerate and reduce the cost of probe development and drug discovery efforts in academia. We assemble nine data sets from realistic HTS campaigns representing major families of drug target proteins for benchmarking LB-CADD methods. Each data set is public domain through PubChem and carefully collated through confirmation screens validating active compounds. These data sets provide the foundation for benchmarking a new cheminformatics framework BCL::ChemInfo, which is freely available for non-commercial use. Quantitative structure activity relationship (QSAR models are built using Artificial Neural Networks (ANNs, Support Vector Machines (SVMs, Decision Trees (DTs, and Kohonen networks (KNs. Problem-specific descriptor optimization protocols are assessed including Sequential Feature Forward Selection (SFFS and various information content measures. Measures of predictive power and confidence are evaluated through cross-validation, and a consensus prediction scheme is tested that combines orthogonal machine learning algorithms into a single predictor. Enrichments ranging from 15 to 101 for a TPR cutoff of 25% are observed.

Eventos toxicológicos relacionados a medicamentos no Estado de São Paulo Drug-related toxic events in the state of São Paulo, Brazil

Directory of Open Access Journals (Sweden)

Eliane Gandolfi

2006-12-01

Full Text Available OBJETIVO: Analisar as características epidemiológicas dos eventos toxicológicos relacionados a medicamentos. MÉTODOS: Realizou-se um estudo epidemiológico descritivo de série de casos. Utilizando a categoria "evento toxicológico relacionado a medicamentos", analisaram-se 6.673 casos registrados em centros de assistência toxicológica do Estado de São Paulo, no ano de 1998. As variáveis estudadas compreenderam características dos eventos, das pessoas afetadas, dos agentes tóxicos e das circunstâncias envolvidas. A análise dos agentes tóxicos considerou três níveis de desagregação: grupos terapêuticos, princípios ativos e nomes comerciais. RESULTADOS: Os medicamentos ocuparam o primeiro lugar entre todos os tipos de agentes tóxicos registrados pelos centros. Os eventos toxicológicos relacionados a medicamentos caracterizaram-se por serem registrados por telefone (78,5%, a partir de hospitais (86,6%; originaram-se de exposições agudas, pela via oral (90,2%, ocorridas em residência (85,7% de área urbana (95%. Houve predomínio do sexo feminino (59% e maior concentração na primeira década de vida (49,4%, sobretudo aos dois e três anos de idade. Os princípios ativos mais freqüentemente encontrados foram: fenobarbital, diazepam, haloperidol, carbamazepina e bromazepam. As principais circunstâncias foram as acidentais (38,8% e tentativas de suicídio (36,5%. Entre os princípios ativos relacionados predominaram os dos grupos terapêuticos psiquiatria, analgesia/anestesia e respiratório. CONCLUSÕES: Aponta-se a necessidade de cumprimento da legislação quanto à venda de medicamentos sob receituário médico e de construção da toxicovigilância conforme diretrizes do Sistema Único de Saúde.OBJECTIVE: To assess the epidemiological characteristics of drug-related toxic events in the State of São Paulo, Brazil. METHODS: A descriptive epidemiological case series study was conducted. Using the category "drug

Operational forecast products and applications based on WRF/Chem

Science.gov (United States)

Hirtl, Marcus; Flandorfer, Claudia; Langer, Matthias; Mantovani, Simone; Olefs, Marc; Schellander-Gorgas, Theresa

2015-04-01

The responsibilities of the national weather service of Austria (ZAMG) include the support of the federal states and the public in questions connected to the protection of the environment in the frame of advisory and counseling services as well as expert opinions. The ZAMG conducts daily Air-Quality forecasts using the on-line coupled model WRF/Chem. The mother domain expands over Europe, North Africa and parts of Russia. The nested domain includes the alpine region and has a horizontal resolution of 4 km. Local emissions (Austria) are used in combination with European inventories (TNO and EMEP) for the simulations. The modeling system is presented and the results from the evaluation of the assimilation of pollutants using the 3D-VAR software GSI is shown. Currently observational data (PM10 and O3) from the Austrian Air-Quality network and from European stations (EEA) are assimilated into the model on an operational basis. In addition PM maps are produced using Aerosol Optical Thickness (AOT) observations from MODIS in combination with model data using machine learning techniques. The modeling system is operationally evaluated with different data sets. The emphasis of the application is on the forecast of pollutants which are compared to the hourly values (PM10, O3 and NO2) of the Austrian Air-Quality network. As the meteorological conditions are important for transport and chemical processes, some parameters like wind and precipitation are automatically evaluated (SAL diagrams, maps, …) with other models (e.g. ECMWF, AROME, …) and ground stations via web interface. The prediction of the AOT is also important for operators of solar power plants. In the past Numerical Weather Prediction (NWP) models were used to predict the AOT based on cloud forecasts at the ZAMG. These models do not consider the spatial and temporal variation of the aerosol distribution in the atmosphere with a consequent impact on the accuracy of forecasts especially during clear-sky days

Effects on Student Achievement in General Chemistry Following Participation in an Online Preparatory Course. ChemPrep, a Voluntary, Self-Paced, Online Introduction to Chemistry

Science.gov (United States)

Botch, Beatrice; Day, Roberta; Vining, William; Stewart, Barbara; Rath, Kenneth; Peterfreund, Alan; Hart, David

2007-03-01

ChemPrep was developed to be a stand-alone preparatory short-course to help students succeed in general chemistry. It is Web-based and delivered using the OWL system. Students reported that the ChemPrep materials (short information pages, parameterized questions with detailed feedback, tutorials, and answers to questions through the OWL message system) permitted them to work independently without the need for textbook or lecture. On average, students who completed ChemPrep had higher grades in the subsequent GenChem, Nursing, and Honors chemistry courses, with a greater percentage achieving a grade of C- or higher. Participation in ChemPrep was voluntary, and more women than men responded. Students in the Honors course enrolled in ChemPrep in higher percentages than students in GenChem and Nursing. SAT and departmental math placement exam scores were used as proxy measures of prior achievement and ability. Based on these, Honors chemistry ChemPrep users were on par with their peers but performed better in the course than non-users. In GenChem and Nursing chemistry courses, ChemPrep helped students of high prior achievement and ability perform better than their achievement scores would predict. Weaker or less motivated students did not respond to the voluntary offerings of ChemPrep in the same numbers as stronger or more motivated students, and we are seeking alternate ways to reach this population.

Cannabis sintético: aspectos toxicológicos, usos clínicos y droga de diseño

Directory of Open Access Journals (Sweden)

Andrés Felipe Casadiego Mesa

2015-07-01

Full Text Available La planta Cannabis Sativa, tiene un largo historial de uso en el transcurso de la humanidad y desde hace varias décadas, se ha retomado el interés por ella debido a su potencial terapéutico relacionado con diversidad de patologías. Sin embargo, el acercamiento a los aspectos toxicológicos, clínicos y terapéuticos de la planta y sus derivados sintéticos se ha visto limitado, debido a las connotaciones culturales y legales que existen en la actualidad alrededor de su uso, ya que dichos derivados sintéticos están siendo utilizados con fines recreativos, exponiendo a gran cantidad de personas a riesgos en su salud. Así pues, este artículo expondrá algunas generalidades sobre la planta, el sistema endocannabinoide y sus ligandos, su uso como droga de síntesis y su uso terapéutico, principalmente en las enfermedades neurodegenerativas del Parkinson y el Alzheimer.

pH and temperature dual-sensitive liposome gel based on novel cleavable mPEG-Hz-CHEMS polymeric vaginal delivery system

Directory of Open Access Journals (Sweden)

Chen D

2012-05-01

Full Text Available Daquan Chen,1,2 Kaoxiang Sun,1,2 Hongjie Mu,1 Mingtan Tang,3 Rongcai Liang,1,2 Aiping Wang,1,2 Shasha Zhou,1 Haijun Sun,1 Feng Zhao,1 Jianwen Yao,1 Wanhui Liu1,21School of Pharmacy, Yantai University, 2State Key Laboratory of Longacting and Targeting Drug Delivery Systems, Yantai, 3School of Pharmaceutical Sciences, Shandong University, Jinan, People's Republic of ChinaBackground: In this study, a pH and temperature dual-sensitive liposome gel based on a novel cleavable hydrazone-based pH-sensitive methoxy polyethylene glycol 2000-hydrazone-cholesteryl hemisuccinate (mPEG-Hz-CHEMS polymer was used for vaginal administration.Methods: The pH-sensitive, cleavable mPEG-Hz-CHEMS was designed as a modified pH-sensitive liposome that would selectively degrade under locally acidic vaginal conditions. The novel pH-sensitive liposome was engineered to form a thermogel at body temperature and to degrade in an acidic environment.Results: A dual-sensitive liposome gel with a high encapsulation efficiency of arctigenin was formed and improved the solubility of arctigenin characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry. The dual-sensitive liposome gel with a sol-gel transition at body temperature was degraded in a pH-dependent manner, and was stable for a long period of time at neutral and basic pH, but cleavable under acidic conditions (pH 5.0. Arctigenin encapsulated in a dual-sensitive liposome gel was more stable and less toxic than arctigenin loaded into pH-sensitive liposomes. In vitro drug release results indicated that dual-sensitive liposome gels showed constant release of arctigenin over 3 days, but showed sustained release of arctigenin in buffers at pH 7.4 and pH 9.0.Conclusion: This research has shed some light on a pH and temperature dual-sensitive liposome gel using a cleavable mPEG-Hz-CHEMS polymer for vaginal delivery.Keywords: mPEG-Hz-CHEMS polymer, pH-sensitive liposomes, thermosensitive

WRF-Chem Model Simulations of Arizona Dust Storms

Science.gov (United States)

Mohebbi, A.; Chang, H. I.; Hondula, D.

2017-12-01

The online Weather Research and Forecasting model with coupled chemistry module (WRF-Chem) is applied to simulate the transport, deposition and emission of the dust aerosols in an intense dust outbreak event that took place on July 5th, 2011 over Arizona. Goddard Chemistry Aerosol Radiation and Transport (GOCART), Air Force Weather Agency (AFWA), and University of Cologne (UoC) parameterization schemes for dust emission were evaluated. The model was found to simulate well the synoptic meteorological conditions also widely documented in previous studies. The chemistry module performance in reproducing the atmospheric desert dust load was evaluated using the horizontal field of the Aerosol Optical Depth (AOD) from Moderate Resolution Imaging Spectro (MODIS) radiometer Terra/Aqua and Aerosol Robotic Network (AERONET) satellites employing standard Dark Target (DT) and Deep Blue (DB) algorithms. To assess the temporal variability of the dust storm, Particulate Matter mass concentration data (PM10 and PM2.5) from Arizona Department of Environmental Quality (AZDEQ) ground-based air quality stations were used. The promising performance of WRF-Chem indicate that the model is capable of simulating the right timing and loading of a dust event in the planetary-boundary-layer (PBL) which can be used to forecast approaching severe dust events and to communicate an effective early warning.

pH and temperature dual-sensitive liposome gel based on novel cleavable mPEG-Hz-CHEMS polymeric vaginal delivery system

Science.gov (United States)

Chen, Daquan; Sun, Kaoxiang; Mu, Hongjie; Tang, Mingtan; Liang, Rongcai; Wang, Aiping; Zhou, Shasha; Sun, Haijun; Zhao, Feng; Yao, Jianwen; Liu, Wanhui

2012-01-01

Background In this study, a pH and temperature dual-sensitive liposome gel based on a novel cleavable hydrazone-based pH-sensitive methoxy polyethylene glycol 2000-hydrazone-cholesteryl hemisuccinate (mPEG-Hz-CHEMS) polymer was used for vaginal administration. Methods The pH-sensitive, cleavable mPEG-Hz-CHEMS was designed as a modified pH-sensitive liposome that would selectively degrade under locally acidic vaginal conditions. The novel pH-sensitive liposome was engineered to form a thermogel at body temperature and to degrade in an acidic environment. Results A dual-sensitive liposome gel with a high encapsulation efficiency of arctigenin was formed and improved the solubility of arctigenin characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry. The dual-sensitive liposome gel with a sol-gel transition at body temperature was degraded in a pH-dependent manner, and was stable for a long period of time at neutral and basic pH, but cleavable under acidic conditions (pH 5.0). Arctigenin encapsulated in a dual-sensitive liposome gel was more stable and less toxic than arctigenin loaded into pH-sensitive liposomes. In vitro drug release results indicated that dual-sensitive liposome gels showed constant release of arctigenin over 3 days, but showed sustained release of arctigenin in buffers at pH 7.4 and pH 9.0. Conclusion This research has shed some light on a pH and temperature dual-sensitive liposome gel using a cleavable mPEG-Hz-CHEMS polymer for vaginal delivery. PMID:22679372

Cleanup of metals and hydrocarbons contaminated soils using the ChemTech process

International Nuclear Information System (INIS)

Stephenson, R.; Yan, V.; Lim, S.

1997-01-01

The ChemTech soil treatment process, an on-site ex-situ system, comprised of a three-phase fluidized bed to scour, emulsify and chemically leach soil contaminants into a process water, was described. The cleaned soils are then removed from the process circuit by means of a hydrodynamic classifier. At this point they are suitable for return to the excavation site. The process was demonstrated on a pilot scale in January 1997 by Klohn-Crippen Consultants at a demonstration program of emerging and innovative technologies sponsored by the Bay Area Defence Conversion Action Team (BADCAT), to assist with the remediation of twelve closing military bases in the San Francisco area. The ChemTest demonstration involved the removal of copper, chromium, lead and zinc from the Hunter Point Naval Reserve, plus treatability tests on a number of other contaminated soil samples. The ChemTech process was selected by federal and state regulatory agencies from 21 proposed technologies on the basis of performance, effectiveness, low cost, and absence of secondary environmental impacts. This paper provides details of the demonstration program, addresses the applicability of the technology to other sites, and provides cost estimates of unit cleanup costs. 3 refs., 4 tabs., 4 figs

ChemInform Abstract: The Palladium-Catalyzed Aerobic Kinetic Resolution of Secondary Alcohols: Reaction Development, Scope, and Applications.

KAUST Repository

Ebner, David C.; Bagdanoff, Jeffrey T.; Ferreira, Eric M.; McFadden, Ryan; Caspi, Daniel D.; Trend, Raissa M.; Stoltz, Brian M.

2010-01-01

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: The Palladium-Catalyzed Aerobic Kinetic Resolution of Secondary Alcohols: Reaction Development, Scope, and Applications.

KAUST Repository

Ebner, David C.

2010-03-30

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemSession'09 - 6. Warsaw Seminar of the PhD Students in Chemistry - Abstracts; ChemSession'09 - 6. Warszawskie Seminarium Doktorantow Chemikow - Streszczenia

Energy Technology Data Exchange (ETDEWEB)

NONE

2009-07-01

Book of Abstracts contains short descriptions of presentations 3 lectures and 105 posters presented during ChemSession'09 - 6{sup th} Warsaw Seminar of the PhD Students in Chemistry. Several posters were devoted to the radiochemistry, radiochemical analysis, radiation chemistry and radiobiology. Some posters on the material science dealing with materials important to nuclear sciences can be also found.

ChemSession'08 - 5. Warsaw Seminar of the PhD Students in Chemistry - Abstracts; ChemSession'08 - 5. Warszawskie Seminarium Doktorantow Chemikow - Streszczenia

Energy Technology Data Exchange (ETDEWEB)

Madura, I [ed.

2008-07-01

Book of Abstracts consists of short descriptions of presentations: 5 lectures and 127 posters presented during ChemSession'08 - 5{sup th} Warsaw Seminar of the PhD Students in Chemistry. Several posters were devoted to the radiochemistry, radiochemical analysis, radiation chemistry and radiobiology. Some posters on the material science dealing with materials important to nuclear sciences can be also found.

Viral vectors for gene modification of plants as chem/bio sensors.

Energy Technology Data Exchange (ETDEWEB)

Manginell, Monica; Harper, Jason C.; Arango, Dulce C.; Brozik, Susan Marie; Dolan, Patricia L.

2006-11-01

Chemical or biological sensors that are specific, sensitive, and robust allowing intelligence gathering for verification of nuclear non-proliferation treaty compliance and detouring production of weapons of mass destruction are sorely needed. Although much progress has been made in the area of biosensors, improvements in sensor lifetime, robustness, and device packaging are required before these devices become widely used. Current chemical and biological detection and identification techniques require less-than-covert sample collection followed by transport to a laboratory for analysis. In addition to being expensive and time consuming, results can often be inconclusive due to compromised sample integrity during collection and transport. We report here a demonstration of a plant based sensor technology which utilizes mature and seedling plants as chemical sensors. One can envision genetically modifying native plants at a site of interest that can report the presence of specific toxins or chemicals. In this one year project we used a developed inducible expression system to show the feasibility of plant sensors. The vector was designed as a safe, non-infectious vector which could be used to invade, replicate, and introduce foreign genes into mature host plants that then allow the plant to sense chem/bio agents. The genes introduced through the vector included a reporter gene that encodes for green fluorescent protein (GFP) and a gene that encodes for a mammalian receptor that recognizes a chemical agent. Specifically, GFP was induced by the presence of 17-{beta}-Estradiol (estrogen). Detection of fluorescence indicated the presence of the target chemical agent. Since the sensor is a plant, costly device packaging development or manufacturing of the sensor were not required. Additionally, the biological recognition and reporting elements are maintained in a living, natural environment and therefore do not suffer from lifetime disadvantages typical of most biosensing

The semantics of Chemical Markup Language (CML for computational chemistry : CompChem

Directory of Open Access Journals (Sweden)

Phadungsukanan Weerapong

2012-08-01

Full Text Available Abstract This paper introduces a subdomain chemistry format for storing computational chemistry data called CompChem. It has been developed based on the design, concepts and methodologies of Chemical Markup Language (CML by adding computational chemistry semantics on top of the CML Schema. The format allows a wide range of ab initio quantum chemistry calculations of individual molecules to be stored. These calculations include, for example, single point energy calculation, molecular geometry optimization, and vibrational frequency analysis. The paper also describes the supporting infrastructure, such as processing software, dictionaries, validation tools and database repositories. In addition, some of the challenges and difficulties in developing common computational chemistry dictionaries are discussed. The uses of CompChem are illustrated by two practical applications.

The semantics of Chemical Markup Language (CML) for computational chemistry : CompChem.

Science.gov (United States)

Phadungsukanan, Weerapong; Kraft, Markus; Townsend, Joe A; Murray-Rust, Peter

2012-08-07

: This paper introduces a subdomain chemistry format for storing computational chemistry data called CompChem. It has been developed based on the design, concepts and methodologies of Chemical Markup Language (CML) by adding computational chemistry semantics on top of the CML Schema. The format allows a wide range of ab initio quantum chemistry calculations of individual molecules to be stored. These calculations include, for example, single point energy calculation, molecular geometry optimization, and vibrational frequency analysis. The paper also describes the supporting infrastructure, such as processing software, dictionaries, validation tools and database repositories. In addition, some of the challenges and difficulties in developing common computational chemistry dictionaries are discussed. The uses of CompChem are illustrated by two practical applications.

Interactive Gaussian Graphical Models for Discovering Depth Trends in ChemCam Data

Science.gov (United States)

Oyen, D. A.; Komurlu, C.; Lanza, N. L.

2018-04-01

Interactive Gaussian graphical models discover surface compositional features on rocks in ChemCam targets. Our approach visualizes shot-to-shot relationships among LIBS observations, and identifies the wavelengths involved in the trend.

ChemAND{sup TM} - a system health monitor for plant chemistry

Energy Technology Data Exchange (ETDEWEB)

Turner, C.W.; Mitchel, G.R.; Balakrishnan, P.V.; Tosello, G

1999-07-01

Effective management of plant systems throughout their lifetime requires much more than data acquisition and display - it requires that the plant's system health be continually monitored and managed. AECL has developed a System Health Monitor called ChemAND for CANDU plant chemistry. ChemAND, a Chemistry ANalysis and Diagnostic system, monitors key chemistry parameters in the heat transport system, moderator-cover gas, annulus gas, and the steam cycle during full-power operation and feeds these parameters to models that calculate the effect of current plant operating conditions on the present and future health of the system. Chemistry data from each of the systems are extracted on a regular basis from the plant's Historical Data Server and are sorted according to function, e.g., indicators for condenser in-leakage, air in-leakage, heavy water leakage into the annulus gas, fuel failure, etc. Each parameter is conveniently displayed and is trended along with its alarm limits. ChemAND currently has two analytical models developed for the balance-of-plant. CHEMSOLV calculates crevice chemistry conditions in the steam generator (SG) from either the SG blowdown chemistry conditions or from a simulated condenser leak. This information will be used by operations personnel to evaluate the potential for SG tube corrosion in the crevice region. CHEMSOLV also calculates chemistry conditions throughout the steam-cycle system, as determined by the transport of volatile species such as ammonia, hydrazine, morpholine, and oxygen. A second model, SLUDGE, calculates the deposit loading in the SG as a function of time, based on concentrations of corrosion product in the final feedwater and plant operating conditions. Operations personnel can use this information to predict where to inspect and when to clean. In a future development, SLUDGE will track deposit loading arising from start-up crud bursts and will be used in conjunction with the thermohydraulics code, THIRST, to

ChemProt: A disease chemical biology database

DEFF Research Database (Denmark)

Taboureau, Olivier; Oprea, Tudor I.

2013-01-01

The integration of chemistry, biology, and informatics to study drug actions across multiple biological targets, pathways, and biological systems is an emerging paradigm in drug discovery. Rather than reducing a complex system to simplistic models, fields such as chemogenomics and translational...... informatics are seeking to build a holistic model for a better understanding of the drug pharmacology and clinical effects. Here we will present a webserver called ChemProt that can assist, in silico, the drug actions in the context of cellular and disease networks and contribute in the field of disease...... chemical biology, drug repurposing, and off-target effects prediction....

Incorporation of a Chemical Equilibrium Equation of State into LOCI-Chem

Science.gov (United States)

Cox, Carey F.

2005-01-01

Renewed interest in development of advanced high-speed transport, reentry vehicles and propulsion systems has led to a resurgence of research into high speed aerodynamics. As this flow regime is typically dominated by hot reacting gaseous flow, efficient models for the characteristic chemical activity are necessary for accurate and cost effective analysis and design of aerodynamic vehicles that transit this regime. The LOCI-Chem code recently developed by Ed Luke at Mississippi State University for NASA/MSFC and used by NASA/MSFC and SSC represents an important step in providing an accurate, efficient computational tool for the simulation of reacting flows through the use of finite-rate kinetics [3]. Finite rate chemistry however, requires the solution of an additional N-1 species mass conservation equations with source terms involving reaction kinetics that are not fully understood. In the equilibrium limit, where the reaction rates approach infinity, these equations become very stiff. Through the use of the assumption of local chemical equilibrium the set of governing equations is reduced back to the usual gas dynamic equations, and thus requires less computation, while still allowing for the inclusion of reacting flow phenomenology. The incorporation of a chemical equilibrium equation of state module into the LOCI-Chem code was the primary objective of the current research. The major goals of the project were: (1) the development of a chemical equilibrium composition solver, and (2) the incorporation of chemical equilibrium solver into LOCI-Chem. Due to time and resource constraints, code optimization was not considered unless it was important to the proper functioning of the code.

Regional modelling of polycyclic aromatic hydrocarbons: WRF-Chem-PAH model development and East Asia case studies

Science.gov (United States)

Mu, Qing; Lammel, Gerhard; Gencarelli, Christian N.; Hedgecock, Ian M.; Chen, Ying; Přibylová, Petra; Teich, Monique; Zhang, Yuxuan; Zheng, Guangjie; van Pinxteren, Dominik; Zhang, Qiang; Herrmann, Hartmut; Shiraiwa, Manabu; Spichtinger, Peter; Su, Hang; Pöschl, Ulrich; Cheng, Yafang

2017-10-01

Polycyclic aromatic hydrocarbons (PAHs) are hazardous pollutants, with increasing emissions in pace with economic development in East Asia, but their distribution and fate in the atmosphere are not yet well understood. We extended the regional atmospheric chemistry model WRF-Chem (Weather Research Forecast model with Chemistry module) to comprehensively study the atmospheric distribution and the fate of low-concentration, slowly degrading semivolatile compounds. The WRF-Chem-PAH model reflects the state-of-the-art understanding of current PAHs studies with several new or updated features. It was applied for PAHs covering a wide range of volatility and hydrophobicity, i.e. phenanthrene, chrysene and benzo[a]pyrene, in East Asia. Temporally highly resolved PAH concentrations and particulate mass fractions were evaluated against observations. The WRF-Chem-PAH model is able to reasonably well simulate the concentration levels and particulate mass fractions of PAHs near the sources and at a remote outflow region of East Asia, in high spatial and temporal resolutions. Sensitivity study shows that the heterogeneous reaction with ozone and the homogeneous reaction with the nitrate radical significantly influence the fate and distributions of PAHs. The methods to implement new species and to correct the transport problems can be applied to other newly implemented species in WRF-Chem.

Diagenetic Features Analyzed by ChemCam/Curiosity at Pahrump Hills, Gale Crater, Mars

Science.gov (United States)

Nachon, M.; Mangold, N.; Cousin, A.; Forni, O.; Anderson, R. B.; Blank, J. G.; Calef, F.; Clegg, S.; Fabre, C.; Fisk, M.;

Simulations of the Holuhraun eruption 2014 with WRF-Chem and evaluation with satellite and ground based SO2 measurements

Science.gov (United States)

Hirtl, Marcus; Arnold-Arias, Delia; Flandorfer, Claudia; Maurer, Christian; Mantovani, Simone; Natali, Stefano

2016-04-01

Volcanic eruptions, with gas or/and particle emissions, directly influence our environment, with special significance when they either occur near inhabited regions or are transported towards them. In addition to the well-known affectation of air traffic, with large economic impacts, the ground touching plumes can lead directly to an influence of soil, water and even to a decrease of air quality. The eruption of Holuhraun in August 2014 in central Iceland is the country's largest lava and gas eruption since the Lakagígar eruption in 1783. Nevertheless, very little volcanic ash was produced. The main atmospheric threat from this event was the SO2 pollution that frequently violated the Icelandic National Air Quality Standards in many population centers. However, the SO2 affectation was not limited to Iceland but extended to mainland Europe. The on-line coupled model WRF-Chem is used to simulate the dispersion of SO2 for this event that affected the central European regions. The volcanic emissions are considered in addition to the anthropogenic and biogenic ground sources at European scale. A modified version of WRF-Chem version 4.1 is used in order to use time depending injection heights and mass fluxes which were obtained from in situ observations. WRF-Chem uses complex gas- (RADM2) and aerosol- (MADE-SORGAM) chemistry and is operated on a European domain (12 km resolution), and a nested grid covering the Alpine region (4 km resolution). The study is showing the evaluation of the model simulations with satellite and ground based measurement data of SO2. The analysis is conducted on a data management platform, which is currently developed in the frame of the ESA-funded project TAMP "Technology and Atmospheric Mission Platform": it provides comprehensive functionalities to visualize and numerically compare data from different sources (model, satellite and ground-measurements).

Quantitation of Poly(ADP-Ribose) by Isotope Dilution Mass Spectrometry

DEFF Research Database (Denmark)

Zubel, Tabea; Martello, Rita; Bürkle, Alexander

2017-01-01

PARP inhibitors, which represent a novel class of promising chemotherapeutics. Previously, we have developed a bioanalytical platform based on isotope dilution mass spectrometry (LC-MS/MS) to quantify cellular PAR with unequivocal chemical specificity in absolute terms with femtomol sensitivity...... research, as well as in drug development (Martello et al. ACS Chem Biol 8(7):1567-1575, 2013; Mangerich et al. Toxicol Lett 244:56-71, 2016). Here, we present an improved and adjusted version of the original protocol by Martello/Mangerich et al., which uses UPLC-MS/MS instrumentation....

Effects of low-molecular-weight organic acids on the acute lethality, accumulation, and enzyme activity of cadmium in Eisenia fetida in a simulated soil solution.

Science.gov (United States)

Liu, Hai-Long; Wang, Yu-Jun; Xuan, Liang; Dang, Fei; Zhou, Dong-Mei

2017-04-01

In the present study, the effects of low-molecular-weight organic acids (LMWOAs) on the toxicity of cadmium (Cd) to Eisenia fetida were investigated in a simulated soil solution. The LMWOAs protected E. fetida from Cd toxicity, as indicated by the increased median lethal concentration (LC50) values and the increased activity of superoxide dismutase. In addition, Cd concentrations in E. fetida decreased dramatically in the presence of LMWOAs. These results were likely because of the complexation between Cd and LMWOAs, which decreased the bioavailability and consequential toxicity of Cd to E. fetida. Notably, LMWOAs reduced Cd toxicity in decreasing order (ethylenediamine tetraacetic acid [EDTA] > citric acid > oxalic acid > malic acid > acetic acid), which was consistent with the decreasing complexation constants between LMWOAs and Cd. These results advance our understanding of the interactions between Cd and LMWOAs in soil. Environ Toxicol Chem 2017;36:1005-1011. © 2016 SETAC. © 2016 SETAC.

Eugenol: propiedades farmacológicas y toxicológicas. Ventajas y desventajas de su uso

Directory of Open Access Journals (Sweden)

Raimara González Escobar

2002-08-01

Full Text Available El Eugenol es un derivado fenólico conocido comúnmente como esencia de clavo, que es utilizado desde hace varios siglos en la práctica odontológica. Por sus propiedades farmacológicas tiene diferentes usos. Sus efectos farmacológicos son complejos y dependen de la concentración del Eugenol libre a la cual el tejido se expone. En este trabajo se presentan sus características farmacológicas y toxicológicas; se mencionan algunos de los mecanismos de acción propuestos para ambos efectos, y se exponen algunos de los nuevos materiales que se utilizan actualmente en estomatología; se presentan sus usos y sus ventajas sobre las formulaciones de Eugenol ya existentes.Eugenol is a phenolic derivative, commonly known as "esencia de clavo", which has been used in dental practice for centuries. Its pharmacological properties determined different uses. Its pharmacological effects are complex and depend on the concentration of free Eugenol to which the tissue is exposed. This paper presents the pharmacological and toxicological characteristics of Eugenol; it mentions some of the mechanisms of action proposed for both effects and also presents some of the new materials used in dentistry nowadays. Their uses and advantages over already existing Eugenol formulations are set forth.

A New WRF-Chem Treatment for Studying Regional Scale Impacts of Cloud-Aerosol Interactions in Parameterized Cumuli

Energy Technology Data Exchange (ETDEWEB)

Berg, Larry K.; Shrivastava, ManishKumar B.; Easter, Richard C.; Fast, Jerome D.; Chapman, Elaine G.; Liu, Ying

2015-01-01

A new treatment of cloud-aerosol interactions within parameterized shallow and deep convection has been implemented in WRF-Chem that can be used to better understand the aerosol lifecycle over regional to synoptic scales. The modifications to the model to represent cloud-aerosol interactions include treatment of the cloud dropletnumber mixing ratio; key cloud microphysical and macrophysical parameters (including the updraft fractional area, updraft and downdraft mass fluxes, and entrainment) averaged over the population of shallow clouds, or a single deep convective cloud; and vertical transport, activation/resuspension, aqueous chemistry, and wet removal of aerosol and trace gases in warm clouds. Thesechanges have been implemented in both the WRF-Chem chemistry packages as well as the Kain-Fritsch cumulus parameterization that has been modified to better represent shallow convective clouds. Preliminary testing of the modified WRF-Chem has been completed using observations from the Cumulus Humilis Aerosol Processing Study (CHAPS) as well as a high-resolution simulation that does not include parameterized convection. The simulation results are used to investigate the impact of cloud-aerosol interactions on the regional scale transport of black carbon (BC), organic aerosol (OA), and sulfate aerosol. Based on the simulations presented here, changes in the column integrated BC can be as large as -50% when cloud-aerosol interactions are considered (due largely to wet removal), or as large as +35% for sulfate in non-precipitating conditions due to the sulfate production in the parameterized clouds. The modifications to WRF-Chem version 3.2.1 are found to account for changes in the cloud drop number concentration (CDNC) and changes in the chemical composition of cloud-drop residuals in a way that is consistent with observations collected during CHAPS. Efforts are currently underway to port the changes described here to WRF-Chem version 3.5, and it is anticipated that they

An investigation of methods for injecting emissions from boreal wildfires using WRF-Chem during ARCTAS

Science.gov (United States)

Sessions, W. R.; Fuelberg, H. E.; Kahn, R. A.; Winker, D. M.

2011-06-01

The Weather Research and Forecasting Model (WRF) is considered a "next generation" mesoscale meteorology model. The inclusion of a chemistry module (WRF-Chem) allows transport simulations of chemical and aerosol species such as those observed during NASA's Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) in 2008. The ARCTAS summer deployment phase during June and July coincided with large boreal wildfires in Saskatchewan and Eastern Russia. One of the most important aspects of simulating wildfire plume transport is the height at which emissions are injected. WRF-Chem contains an integrated one-dimensional plume rise model to determine the appropriate injection layer. The plume rise model accounts for thermal buoyancy associated with fires and local atmospheric stability. This paper describes a case study of a 10 day period during the Spring phase of ARCTAS. It compares results from the plume model against those of two more traditional injection methods: Injecting within the planetary boundary layer, and in a layer 3-5 km above ground level. Fire locations are satellite derived from the GOES Wildfire Automated Biomass Burning Algorithm (WF_ABBA) and the MODIS thermal hotspot detection. Two methods for preprocessing these fire data are compared: The prep_chem_sources method included with WRF-Chem, and the Naval Research Laboratory's Fire Locating and Monitoring of Burning Emissions (FLAMBE). Results from the simulations are compared with satellite-derived products from the AIRS, MISR and CALIOP sensors. When FLAMBE provides input to the 1-D plume rise model, the resulting injection heights exhibit the best agreement with satellite-observed injection heights. The FLAMBE-derived heights are more realistic than those utilizing prep_chem_sources. Conversely, when the planetary boundary layer or the 3-5 km a.g.l. layer were filled with emissions, the resulting injection heights exhibit less agreement with observed plume heights

The ChemChar process

International Nuclear Information System (INIS)

Manahan, S.E.; Kinner, L.L.; Larsen, D.W.

1992-01-01

This paper reports on reverse-burn gasification is a thermochemical process that offers a number of advantages over conventional incineration for the treatment of a variety of waste materials. Patented as the ChemChar Process, reverse-burn gasification can treat wastes in the forms of solids, liquids, sludges, and soils. Waste constituents are destroyed by conversion to a combustible gas and to a dry, inert, carbonaceous solid which is either non-hazardous or can be readily mixed with cement to prevent leaching of the radioactive, toxic, or heavy metal constituents that are retained in the char residue or ash. In this way, reverse-burn gasification can be a very effective method for treating organic waste sludges containing heavy metals and mixed wastes consisting of hazardous chemicals contaminated with radioactive substances. As with any gasification waste treatment process, reverse-burn gasification offers inherent advantages in the areas of destruction efficiency and emissions control. This is because, instead of an exhaust gas that must treated to control emissions, gasification produces a combustible gas that is burned. Trace levels of contaminants are destroyed in burning the gas, and a catalyst may be employed, if necessary

Design and Development of ChemInfoCloud: An Integrated Cloud Enabled Platform for Virtual Screening.

Science.gov (United States)

Karthikeyan, Muthukumarasamy; Pandit, Deepak; Bhavasar, Arvind; Vyas, Renu

2015-01-01

The power of cloud computing and distributed computing has been harnessed to handle vast and heterogeneous data required to be processed in any virtual screening protocol. A cloud computing platorm ChemInfoCloud was built and integrated with several chemoinformatics and bioinformatics tools. The robust engine performs the core chemoinformatics tasks of lead generation, lead optimisation and property prediction in a fast and efficient manner. It has also been provided with some of the bioinformatics functionalities including sequence alignment, active site pose prediction and protein ligand docking. Text mining, NMR chemical shift (1H, 13C) prediction and reaction fingerprint generation modules for efficient lead discovery are also implemented in this platform. We have developed an integrated problem solving cloud environment for virtual screening studies that also provides workflow management, better usability and interaction with end users using container based virtualization, OpenVz.

Alkali trace elements in Gale crater, Mars, with ChemCam: Calibration update and geological implications

Science.gov (United States)

Payré, V.; Fabre, C.; Cousin, A.; Sautter, V.; Wiens, R. C.; Forni, O.; Gasnault, O.; Mangold, N.; Meslin, P.-Y.; Lasue, J.; Ollila, A.; Rapin, W.; Maurice, S.; Nachon, M.; Le Deit, L.; Lanza, N.; Clegg, S.

2017-03-01

The Chemistry Camera (ChemCam) instrument onboard Curiosity can detect minor and trace elements such as lithium, strontium, rubidium, and barium. Their abundances can provide some insights about Mars' magmatic history and sedimentary processes. We focus on developing new quantitative models for these elements by using a new laboratory database (more than 400 samples) that displays diverse compositions that are more relevant for Gale crater than the previous ChemCam database. These models are based on univariate calibration curves. For each element, the best model is selected depending on the results obtained by using the ChemCam calibration targets onboard Curiosity. New quantifications of Li, Sr, Rb, and Ba in Gale samples have been obtained for the first 1000 Martian days. Comparing these data in alkaline and magnesian rocks with the felsic and mafic clasts from the Martian meteorite NWA7533—from approximately the same geologic period—we observe a similar behavior: Sr, Rb, and Ba are more concentrated in soluble- and incompatible-element-rich mineral phases (Si, Al, and alkali-rich). Correlations between these trace elements and potassium in materials analyzed by ChemCam reveal a strong affinity with K-bearing phases such as feldspars, K-phyllosilicates, and potentially micas in igneous and sedimentary rocks. However, lithium is found in comparable abundances in alkali-rich and magnesium-rich Gale rocks. This very soluble element can be associated with both alkali and Mg-Fe phases such as pyroxene and feldspar. These observations of Li, Sr, Rb, and Ba mineralogical associations highlight their substitution with potassium and their incompatibility in magmatic melts.

Numerical simulation for regional ozone concentrations: A case study by weather research and forecasting/chemistry (WRF/Chem) model

Energy Technology Data Exchange (ETDEWEB)

Habib Al Razi, Khandakar Md; Hiroshi, Moritomi [Environmental and Renewable Energy System, Graduate School of Engineering, Gifu University, 1-1 Yanagido, Gifu City, 501-1193 (Japan)

2013-07-01

The objective of this research is to better understand and predict the atmospheric concentration distribution of ozone and its precursor (in particular, within the Planetary Boundary Layer (Within 110 km to 12 km) over Kasaki City and the Greater Tokyo Area using fully coupled online WRF/Chem (Weather Research and Forecasting/Chemistry) model. In this research, a serious and continuous high ozone episode in the Greater Tokyo Area (GTA) during the summer of 14–18 August 2010 was investigated using the observation data. We analyzed the ozone and other trace gas concentrations, as well as the corresponding weather conditions in this high ozone episode by WRF/Chem model. The simulation results revealed that the analyzed episode was mainly caused by the impact of accumulation of pollution rich in ozone over the Greater Tokyo Area. WRF/Chem has shown relatively good performance in modeling of this continuous high ozone episode, the simulated and the observed concentrations of ozone, NOx and NO2 are basically in agreement at Kawasaki City, with best correlation coefficients of 0.87, 0.70 and 0.72 respectively. Moreover, the simulations of WRF/Chem with WRF preprocessing software (WPS) show a better agreement with meteorological observations such as surface winds and temperature profiles in the ground level of this area. As a result the surface ozone simulation performances have been enhanced in terms of the peak ozone and spatial patterns, whereas WRF/Chem has been succeeded to generate meteorological fields as well as ozone, NOx, NO2 and NO.

Retrieval of water vapor column abundance and aerosol properties from ChemCam passive sky spectroscopy

Science.gov (United States)

McConnochie, Timothy H.; Smith, Michael D.; Wolff, Michael J.; Bender, Steve; Lemmon, Mark; Wiens, Roger C.; Maurice, Sylvestre; Gasnault, Olivier; Lasue, Jeremie; Meslin, Pierre-Yves; Harri, Ari-Matti; Genzer, Maria; Kemppinen, Osku; Martínez, Germán M.; DeFlores, Lauren; Blaney, Diana; Johnson, Jeffrey R.; Bell, James F.

2018-06-01

We derive water vapor column abundances and aerosol properties from Mars Science Laboratory (MSL) ChemCam passive mode observations of scattered sky light. This paper covers the methodology and initial results for water vapor and also provides preliminary results for aerosols. The data set presented here includes the results of 113 observations spanning from Mars Year 31 Ls = 291° (March 30, 2013) to Mars Year 33 Ls= 127° (March 24, 2016). Each ChemCam passive sky observation acquires spectra at two different elevation angles. We fit these spectra with a discrete-ordinates multiple scattering radiative transfer model, using the correlated-k approximation for gas absorption bands. The retrieval proceeds by first fitting the continuum of the ratio of the two elevation angles to solve for aerosol properties, and then fitting the continuum-removed ratio to solve for gas abundances. The final step of the retrieval makes use of the observed CO2 absorptions and the known CO2 abundance to correct the retrieved water vapor abundance for the effects of the vertical distribution of scattering aerosols and to derive an aerosol scale height parameter. Our water vapor results give water vapor column abundance with a precision of ±0.6 precipitable microns and systematic errors no larger than ±0.3 precipitable microns, assuming uniform vertical mixing. The ChemCam-retrieved water abundances show, with only a few exceptions, the same seasonal behavior and the same timing of seasonal minima and maxima as the TES, CRISM, and REMS-H data sets that we compare them to. However ChemCam-retrieved water abundances are generally lower than zonal and regional scale from-orbit water vapor data, while at the same time being significantly larger than pre-dawn REMS-H abundances. Pending further analysis of REMS-H volume mixing ratio uncertainties, the differences between ChemCam and REMS-H pre-dawn mixing ratios appear to be much too large to be explained by large scale circulations and thus

An investigation of methods for injecting emissions from boreal wildfires using WRF-Chem during ARCTAS

Directory of Open Access Journals (Sweden)

W. R. Sessions

2011-06-01

Full Text Available The Weather Research and Forecasting Model (WRF is considered a "next generation" mesoscale meteorology model. The inclusion of a chemistry module (WRF-Chem allows transport simulations of chemical and aerosol species such as those observed during NASA's Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS in 2008. The ARCTAS summer deployment phase during June and July coincided with large boreal wildfires in Saskatchewan and Eastern Russia.

One of the most important aspects of simulating wildfire plume transport is the height at which emissions are injected. WRF-Chem contains an integrated one-dimensional plume rise model to determine the appropriate injection layer. The plume rise model accounts for thermal buoyancy associated with fires and local atmospheric stability. This paper describes a case study of a 10 day period during the Spring phase of ARCTAS. It compares results from the plume model against those of two more traditional injection methods: Injecting within the planetary boundary layer, and in a layer 3–5 km above ground level. Fire locations are satellite derived from the GOES Wildfire Automated Biomass Burning Algorithm (WF_ABBA and the MODIS thermal hotspot detection. Two methods for preprocessing these fire data are compared: The prep_chem_sources method included with WRF-Chem, and the Naval Research Laboratory's Fire Locating and Monitoring of Burning Emissions (FLAMBE. Results from the simulations are compared with satellite-derived products from the AIRS, MISR and CALIOP sensors.

When FLAMBE provides input to the 1-D plume rise model, the resulting injection heights exhibit the best agreement with satellite-observed injection heights. The FLAMBE-derived heights are more realistic than those utilizing prep_chem_sources. Conversely, when the planetary boundary layer or the 3–5 km a.g.l. layer were filled with emissions, the resulting injection heights exhibit less

Alkali trace elements in Gale crater, Mars, with ChemCam: Calibration update and geological implications

International Nuclear Information System (INIS)

Payre, Valerie; Fabre, Cecile; Cousin, Agnes; Sautter, Violaine; Wiens, Roger Craig

2017-01-01

The Chemistry Camera (ChemCam) instrument onboard Curiosity can detect minor and trace elements such as lithium, strontium, rubidium, and barium. Their abundances can provide some insights about Mars' magmatic history and sedimentary processes. We focus on developing new quantitative models for these elements by using a new laboratory database (more than 400 samples) that displays diverse compositions that are more relevant for Gale crater than the previous ChemCam database. These models are based on univariate calibration curves. For each element, the best model is selected depending on the results obtained by using the ChemCam calibration targets onboard Curiosity. New quantifications of Li, Sr, Rb, and Ba in Gale samples have been obtained for the first 1000 Martian days. Comparing these data in alkaline and magnesian rocks with the felsic and mafic clasts from the Martian meteorite NWA7533—from approximately the same geologic period—we observe a similar behavior: Sr, Rb, and Ba are more concentrated in soluble- and incompatible-element-rich mineral phases (Si, Al, and alkali-rich). Correlations between these trace elements and potassium in materials analyzed by ChemCam reveal a strong affinity with K-bearing phases such as feldspars, K-phyllosilicates, and potentially micas in igneous and sedimentary rocks. However, lithium is found in comparable abundances in alkali-rich and magnesium-rich Gale rocks. This very soluble element can be associated with both alkali and Mg-Fe phases such as pyroxene and feldspar. Here, these observations of Li, Sr, Rb, and Ba mineralogical associations highlight their substitution with potassium and their incompatibility in magmatic melts.

HExpoChem: a systems biology resource to explore human exposure to chemicals

DEFF Research Database (Denmark)

Taboureau, Olivier; Jacobsen, Ulrik Plesner; Kalhauge, Christian Gram

2013-01-01

of computational biology approaches are needed to assess the health risks of chemical exposure. Here we present HExpoChem, a tool based on environmental chemicals and their bioactivities on human proteins with the objective of aiding the qualitative exploration of human exposure to chemicals. The chemical...

The performance of the 'CentrifiChem' parallel fast analyser using packaged reagents.

Science.gov (United States)

Henry, P; Saunders, R A

1975-05-01

The CentrifiChem system was used with packaged reagent kits for the following determinations: albumin, alanine and aspartate aminotransferases, creatinine, glucose, and alpha-hydroxybutyrate and lactate dehydrogenases. The linearity obtainable for each assay was investigated, and particular attention was paid to finding the most suitable instrument settings.

The ChemCam Instrument Suite on the Mars Science Laboratory (MSL) Rover: Body Unit and Combined System Tests

International Nuclear Information System (INIS)

Wiens, Roger C.; Barraclough, Bruce; Barkley, Walter C.; Bender, Steve; Bernardin, John; Bultman, Nathan; Clanton, Robert C.; Clegg, Samuel; Delapp, Dorothea; Dingler, Robert; Enemark, Don; Flores, Mike; Hale, Thomas; Lanza, Nina; Lasue, Jeremie; Latino, Joseph; Little, Cynthia; Morrison, Leland; Nelson, Tony; Romero, Frank; Salazar, Steven; Stiglich, Ralph; Storms, Steven; Trujillo, Tanner; Ulibarri, Mike; Vaniman, David; Whitaker, Robert; Witt, James; Maurice, Sylvestre; Bouye, Marc; Cousin, Agnes; Cros, Alain; D'Uston, Claude; Forni, Olivier; Gasnault, Olivier; Kouach, Driss; Lasue, Jeremie; Pares, Laurent; Poitrasson, Franck; Striebig, Nicolas; Thocaven, Jean-Jacques; Saccoccio, Muriel; Perez, Rene; Bell, James F. III; Hays, Charles; Blaney, Diana; DeFlores, Lauren; Elliott, Tom; Kan, Ed; Limonadi, Daniel; Lindensmith, Chris; Miller, Ed; Reiter, Joseph W.; Roberts, Tom; Simmonds, John J.; Warner, Noah; Blank, Jennifer; Bridges, Nathan; Cais, Phillippe; Clark, Benton; Cremers, David; Dyar, M. Darby; Fabre, Cecile; Herkenhoff, Ken; Kirkland, Laurel; Landis, David; Langevin, Yves; Lanza, Nina; Newsom, Horton; Ollila, Ann; LaRocca, Frank; Ott, Melanie; Mangold, Nicolas; Manhes, Gerard; Mauchien, Patrick; Blank, Jennifer; McKay, Christopher; Mooney, Joe; Provost, Cheryl; Morris, Richard V.; Sautter, Violaine; Sautter, Violaine; Waterbury, Rob; Wong-Swanson, Belinda; Barraclough, Bruce; Bender, Steve; Vaniman, David

2012-01-01

The ChemCam instrument suite on the Mars Science Laboratory (MSL) rover Curiosity provides remote compositional information using the first laser-induced breakdown spectrometer (LIBS) on a planetary mission, and provides sample texture and morphology data using a remote micro-imager (RMI). Overall, ChemCam supports MSL with five capabilities: remote classification of rock and soil characteristics; quantitative elemental compositions including light elements like hydrogen and some elements to which LIBS is uniquely sensitive (e.g., Li, Be, Rb, Sr, Ba); remote removal of surface dust and depth profiling through surface coatings; context imaging; and passive spectroscopy over the 240-905 nm range. ChemCam is built in two sections: The mast unit, consisting of a laser, telescope, RMI, and associated electronics, resides on the rover's mast, and is described in a companion paper. ChemCam's body unit, which is mounted in the body of the rover, comprises an optical de-multiplexer, three spectrometers, detectors, their coolers, and associated electronics and data handling logic. Additional instrument components include a 6 m optical fiber which transfers the LIBS light from the telescope to the body unit, and a set of onboard calibration targets. ChemCam was integrated and tested at Los Alamos National Laboratory where it also underwent LIBS calibration with 69 geological standards prior to integration with the rover. Post-integration testing used coordinated mast and instrument commands, including LIBS line scans on rock targets during system-level thermal-vacuum tests. In this paper we describe the body unit, optical fiber, and calibration targets, and the assembly, testing, and verification of the instrument prior to launch. (authors)

Mixed waste treatment using the ChemChar thermolytic detoxification technique

Energy Technology Data Exchange (ETDEWEB)

Kuchynka, D. [Mirage Systems, Sunnyvale, CA (United States)

1995-10-01

The diversity of mixed waste matrices contained at Department of Energy sites that require treatment preclude a single, universal treatment technology capable of handling sludges, solids, heterogeneous debris, aqueous and organic liquids and soils. This report describes the ChemChar thermolytic detoxification process. The process is a thermal, chemically reductive technology that converts the organic portion of mixed wastes to a synthesis gas, while simultaneously absorbing volatile inorganics on a carbon-based char.

Modelling the urban air quality in Hamburg with the new city-scale chemistry transport model CityChem

Science.gov (United States)

Karl, Matthias; Ramacher, Martin; Aulinger, Armin; Matthias, Volker; Quante, Markus

2017-04-01

Air quality modelling plays an important role by providing guidelines for efficient air pollution abatement measures. Currently, most urban dispersion models treat air pollutants as passive tracer substances or use highly simplified chemistry when simulating air pollutant concentrations on the city-scale. The newly developed urban chemistry-transport model CityChem has the capability of modelling the photochemical transformation of multiple pollutants along with atmospheric diffusion to produce pollutant concentration fields for the entire city on a horizontal resolution of 100 m or even finer and a vertical resolution of 24 layers up to 4000 m height. CityChem is based on the Eulerian urban dispersion model EPISODE of the Norwegian Institute for Air Research (NILU). CityChem treats the complex photochemistry in cities using detailed EMEP chemistry on an Eulerian 3-D grid, while using simple photo-stationary equilibrium on a much higher resolution grid (receptor grid), i.e. close to industrial point sources and traffic sources. The CityChem model takes into account that long-range transport contributes to urban pollutant concentrations. This is done by using 3-D boundary concentrations for the city domain derived from chemistry-transport simulations with the regional air quality model CMAQ. For the study of the air quality in Hamburg, CityChem was set-up with a main grid of 30×30 grid cells of 1×1 km2 each and a receptor grid of 300×300 grid cells of 100×100 m2. The CityChem model was driven with meteorological data generated by the prognostic meteorology component of the Australian chemistry-transport model TAPM. Bottom-up inventories of emissions from traffic, industry, households were based on data of the municipality of Hamburg. Shipping emissions for the port of Hamburg were taken from the Clean North Sea Shipping project. Episodes with elevated ozone (O3) were of specific interest for this study, as these are associated with exceedances of the World

Caracterización fármaco-toxicológica de la planta medicinal Sambucus nigra subsp. canadensis (L. R. Bolli Pharmaceutical-toxicological characterization of medicinal plant Sambucus nigra subsp. canadensis (L. R. Bolli

Directory of Open Access Journals (Sweden)

Oneyda Clapé Laffita

2011-12-01

Full Text Available El objetivo de la monografía consistió en la caracterización fármaco-toxicológica de Sambucus nigra subsp. canadensis (L. R. Bolli, planta tradicional cubana con actividad antiinflamatoria, entre otras. Se presentan aspectos farmacológicos como composición fitoquímica, propiedades atribuidas popularmente y comprobadas científicamente, posología, reacciones adversas, advertencias, interacciones, toxicidad, precauciones y contraindicaciones. Se concluye que con la monografía fármaco-toxicológica de esta planta medicinal, se dispone de una completa información, como documentación indispensable para actualizar las bases de datos nacionales e internacionales al respecto, con vistas a desarrollar nuevos fitofármacos, en especial antiinflamatorios con bajo potencial de efectos adversos.The objective of the monograph was the pharmacological and toxicological characterization of Sambucus nigra subspecies canadensis(L. R. Bolli, a Cuban traditional plant with anti-inflammatory action, among others. Several pharmacological aspects such as phytochemical composition; scientifically tested properties attributed by the population; posology; adverse reactions; warnings; interactions; toxicity; precautions and counterindications were presented. It was concluded that the pharmaceutical and toxicological monograph of this plant provides full information as indispensable documentation to update national and international databases, with a view to developing new pharmaceuticals, particularly anti-inflammatory drugs with low adverse effect potential.

Identifying Known Unknowns Using the USEPA CompTox Chemistry Dashboard AnalytBioanlytChem Data

Data.gov (United States)

U.S. Environmental Protection Agency — In this research, the performance of the Dashboard for identifying “known unknowns” was evaluated against that of the online ChemSpider database, one of the primary...

ChemCam passive reflectance spectroscopy of surface materials at the Curiosity landing site, Mars

Science.gov (United States)

Johnson, Jeffrey R.; Bell, J. F.; Bender, S.; Blaney, D.; Cloutis, E.; DeFlores, L.; Ehlmann, B.; Gasnault, O.; Gondet, B.; Kinch, K.; Lemmon, M.; Le Mouélic, S.; Maurice, S.; Rice, M.; Wiens, R. C.

2015-03-01

The spectrometers on the Mars Science Laboratory (MSL) ChemCam instrument were used in passive mode to record visible/near-infrared (400-840 nm) radiance from the martian surface. Using the onboard ChemCam calibration targets' housing as a reflectance standard, we developed methods to collect, calibrate, and reduce radiance observations to relative reflectance. Such measurements accurately reproduce the known reflectance spectra of other calibration targets on the rover, and represent the highest spatial resolution (0.65 mrad) and spectral sampling (rocks and soils match those from orbital observations and multispectral data from the MSL Mastcam camera. Preliminary analyses of the band depths, spectral slopes, and reflectance ratios of the more than 2000 spectra taken during the first year of MSL operations demonstrate at least six spectral classes of materials distinguished by variations in ferrous and ferric components. Initial comparisons of ChemCam spectra to laboratory spectra of minerals and Mars analog materials demonstrate similarities with palagonitic soils and indications of orthopyroxene in some dark rocks. Magnesium-rich "raised ridges" tend to exhibit distinct near-infrared slopes. The ferric absorption downturn typically found for martian materials at rocks and drill tailings, consistent with their more ferrous nature. Calcium-sulfate veins exhibit the highest relative reflectances observed, but are still relatively red owing to the effects of residual dust. Such dust is overall less prominent on rocks sampled within the "blast zone" immediately surrounding the landing site. These samples were likely affected by the landing thrusters, which partially removed the ubiquitous dust coatings. Increased dust coatings on the calibration targets during the first year of the mission were documented by the ChemCam passive measurements as well. Ongoing efforts to model and correct for this dust component should improve calibration of the relative reflectance

Aerosol comparisons between sunphotometry / sky radiometry and the GEOS-Chem model

Science.gov (United States)

Chaubey, J. P.; Hesaraki, S.; O'Neill, N. T.; Saha, A.; Martin, R.; Lesins, G. B.; Abboud, I.

2014-12-01

Comparisons of aerosol optical depth (AOD), spectral AOD parameters and microphysical parameters derived from AEROCAN / AERONET sunphotometer / sky radiometer data acquired over Canada were compared with GEOS-Chem (Geos5,v9-01-03) estimations. The Canadian sites were selected so as to encompass a representative variety of different aerosol types ranging from fine mode (submicron) pollution and smoke aerosols, coarse mode (supermicron) dust, fine and coarse mode marine aerosols, volcanic (fine mode) sulfates and volcanic (coarse mode) ash, etc). A particular focus was placed on comparisons at remote Canadian sites with a further focus on Arctic sites. The analysis included meteorological-scale event comparisons as well as seasonal and yearly comparisons on a climatological scale. The investigations were given a further aerosol type context by comparing optical retrievals of fine and coarse mode AOD with the AODs of the different aerosol types predicted by GEOS-Chem. The effects of temporal and spectral cloud screening of the sunphotometer data on the quality and robustness of these comparisons was the object of an important supporting investigation. The results of this study will be presented for a 3 year period from 2009 to 2011.

Microwave discharge electrodeless lamps (MDEL). III. A novel tungsten-triggered MDEL device emitting VUV and UVC radiation for use in wastewater treatment.

Science.gov (United States)

Horikoshi, Satoshi; Miura, Takashi; Kajitani, Masatsugu; Serpone, Nick

2008-03-01

Exposure to low doses of the xenoestrogen bisphenol A (BPA) and to the hormonal 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide, an environmental endocrine disruptor, can have serious health consequences such as the induction of mammary gland ductal hyperplasias and carcinoma (LaChapelle et al., Reprod. Toxicol., 2007, 23, 20; Murray et al., Reprod. Toxicol., 2007, 23, 383). To the extent that these toxins are present in wastewaters (Donald et al., Sci. Total Environ. 1999, 231, 173; Brotons et al., Environ. Health Perspect. 1994, 103, 608; Olea et al., Environ. Health Perspect. 1996, 104, 298; Biles et al., J. Agric. Food Chem. 1997, 45, 3541; Markey et al., J. Steroid Biochem. Mol. Biol., 2003, 83, 235), we examined their oxidative destruction in aqueous media by a novel light source. A tungsten-triggered microwave discharge electrodeless lamp (W-MDEL) was fabricated for possible use in wastewater treatment using vacuum UV-transparent quartz in which a tungsten trigger, also embedded in quartz, was attached to the MDEL to aid in the self-ignition of the lamp on irradiation at low microwave power levels. The quantity of mercury gas in the W-MDEL was optimized by monitoring the continuous radiation and peak intensities of the emitted light in the vacuum UV (VUV) and UVC regions. The usefulness of the W-MDEL device was assessed through the degradation of 2,4-D and BPA in air-equilibrated aqueous media and in oxygen-saturated aqueous media. Enhanced degradation of these two xenoestrogenic toxins was achieved by increasing the number of W-MDEL devices while keeping constant the microwave radiation feeding each W-MDEL lamp. This novel lamp provides an additional light source in the photooxidation of environmental contaminants without the need for a metal-oxide photocatalyst. Under our conditions, process dynamics using the W-MDEL light source are greater than with the more conventional photochemical methods that employ low-pressure Hg arc electrode lamps in synthetic

Soil diversity and hydration as observed by ChemCam at Gale Crater, Mars

NARCIS (Netherlands)

Meslin, P.-Y.; Gasnault, O.; Forni, O.; Schröder, S.; Cousin, A.; Berger, G.; Clegg, S.M.; Lasue, J.; Maurice, S.; Sautter, V.; Le Mouélic, S.; Wiens, R.C.; Fabre, C.; Goetz, W.; Bish, D.; Mangold, N.; Ehlmann, B.; Lanza, N.; Harri, A.-M.; Anderson, R.; Rampe, E.; McConnochie, T.H.; Pinet, P.; Blaney, D.; Léveillé, R.; Archer, D.; Barraclough, B.; Bender, S.; Blake, D.; Blank, J.G.; Bridges, N.; Clark, B.C.; DeFlores, L.; Delapp, D.; Dromart, G.; Dyar, M.D.; Fisk, M.; Gondet, B.; Grotzinger, J.; Herkenhoff, K.; Johnson, J.; Lacour, J.-L.; Langevin, Y.; Leshin, L.; Lewin, E.; Madsen, M.B.; Melikechi, N.; Mezzacappa, A.; Mischna, M.A.; Moores, J.E.; Newsom, H.; Ollila, A.; Perez, R.; Renno, N.; Sirven, J.-B.; Tokar, R.; De La Torre, M.; D'Uston, L.; Vaniman, D.; Yingst, A.; MSL Science Team, the

2013-01-01

The ChemCam instrument, which provides insight into martian soil chemistry at the submillimeter scale, identified two principal soil types along the Curiosity rover traverse: a fine-grained mafic type and a locally derived, coarse-grained felsic type. The mafic soil component is representative of

Calibration of the MSL/ChemCam/LIBS Remote Sensing Composition Instrument

Science.gov (United States)

Wiens, R. C.; Maurice S.; Bender, S.; Barraclough, B. L.; Cousin, A.; Forni, O.; Ollila, A.; Newsom, H.; Vaniman, D.; Clegg, S.;

ChemProt: a disease chemical biology database

DEFF Research Database (Denmark)

Taboureau, Olivier; Nielsen, Sonny Kim; Audouze, Karine Marie Laure

2011-01-01

Systems pharmacology is an emergent area that studies drug action across multiple scales of complexity, from molecular and cellular to tissue and organism levels. There is a critical need to develop network-based approaches to integrate the growing body of chemical biology knowledge with network...... biology. Here, we report ChemProt, a disease chemical biology database, which is based on a compilation of multiple chemical-protein annotation resources, as well as disease-associated protein-protein interactions (PPIs). We assembled more than 700 000 unique chemicals with biological annotation for 30...... evaluation of environmental chemicals, natural products and approved drugs, as well as the selection of new compounds based on their activity profile against most known biological targets, including those related to adverse drug events. Results from the disease chemical biology database associate citalopram...

Nanoplatforms for Detection, Remediation and Protection Against Chem-Bio Warfare

Science.gov (United States)

Denkbaş, E. B.; Bayram, C.; Kavaz, D.; Çirak, T.; Demirbilek, M.

Chemical and biological substances have been used as warfare agents by terrorists by varying degree of sophistication. It is critical that these agents be detected in real-time with high level of sensitively, specificity, and accuracy. Many different types of techniques and systems have been developed to detect these agents. But there are some limitations in these conventional techniques and systems. Limitations include the collection, handling and sampling procedures, detection limits, sample transfer, expensive equipment, personnel training, and detection materials. Due to the unique properties such as quantum effect, very high surface/volume ratio, enhanced surface reactivity, conductivity, electrical and magnetic properties of the nanomaterials offer great opportunity to develop very fast, sensitive, accurate and cost effective detection techniques and systems to detect chemical and biological (chem.-bio) warfare agents. Furthermore, surface modification of the materials is very easy and effective way to get functional or smart surfaces to be used as nano-biosensor platform. In that respect many different types of nanomaterials have been developed and used for the detection, remediation and protection, such as gold and silver nanoparticles, quantum dots, Nano chips and arrays, fluorescent polymeric and magnetic nanoparticles, fiber optic and cantilever based nanobiosensors, nanofibrillar nanostructures etc. This study summarizes preparation and characterization of nanotechnology based approaches for the detection of and remediation and protection against chem.-bio warfare agents.

Inclusion of ash and SO2 emissions from volcanic eruptions in WRF-Chem: development and some applications

Directory of Open Access Journals (Sweden)

M. Stuefer

2013-04-01

Full Text Available We describe a new functionality within the Weather Research and Forecasting (WRF model with coupled Chemistry (WRF-Chem that allows simulating emission, transport, dispersion, transformation and sedimentation of pollutants released during volcanic activities. Emissions from both an explosive eruption case and a relatively calm degassing situation are considered using the most recent volcanic emission databases. A preprocessor tool provides emission fields and additional information needed to establish the initial three-dimensional cloud umbrella/vertical distribution within the transport model grid, as well as the timing and duration of an eruption. From this source condition, the transport, dispersion and sedimentation of the ash cloud can be realistically simulated by WRF-Chem using its own dynamics and physical parameterization as well as data assimilation. Examples of model applications include a comparison of tephra fall deposits from the 1989 eruption of Mount Redoubt (Alaska and the dispersion of ash from the 2010 Eyjafjallajökull eruption in Iceland. Both model applications show good coincidence between WRF-Chem and observations.

Standardized toxicity testing may underestimate ecotoxicity: Environmentally relevant food rations increase the toxicity of silver nanoparticles to Daphnia.

Science.gov (United States)

Stevenson, Louise M; Krattenmaker, Katherine E; Johnson, Erica; Bowers, Alexandra J; Adeleye, Adeyemi S; McCauley, Edward; Nisbet, Roger M

2017-11-01

Daphnia in the natural environment experience fluctuations in algal food supply, with periods when algal populations bloom and seasons when Daphnia have very little algal food. Standardized chronic toxicity tests, used for ecological risk assessment, dictate that Daphnia must be fed up to 400 times more food than they would experience in the natural environment (outside of algal blooms) for a toxicity test to be valid. This disconnect can lead to underestimating the toxicity of a contaminant. We followed the growth, reproduction, and survival of Daphnia exposed to 75 and 200 µg/L silver nanoparticles (AgNPs) at 4 food rations for up to 99 d and found that AgNP exposure at low, environmentally relevant food rations increased the toxicity of AgNPs. Exposure to AgNP at low food rations decreased the survival and/or reproduction of individuals, with potential consequences for Daphnia populations (based on calculated specific population growth rates). We also found tentative evidence that a sublethal concentration of AgNPs (75 µg/L) caused Daphnia to alter energy allocation away from reproduction and toward survival and growth. The present findings emphasize the need to consider resource availability, and not just exposure, in the environment when estimating the effect of a toxicant. Environ Toxicol Chem 2017;36:3008-3018. © 2017 SETAC. © 2017 SETAC.

A Case Study in Competitive Technical and Market Intelligence Support and Lessons Learned for the uChemLab LDRD Grand Challenge Project; TOPICAL

International Nuclear Information System (INIS)

SOUTHWELL, EDWIN T.; GARCIA, MARIE L.; MEYERS, CHARLES E.

2001-01-01

The(mu)ChemLab(trademark) Laboratory Directed Research and Development (LDRD) Grand Challenge project began in October 1996 and ended in September 2000. The technical managers of the(mu)ChemLab(trademark) project and the LDRD office, with the support of a consultant, conducted a competitive technical and market demand intelligence analysis of the(mu)ChemLab(trademark). The managers used this knowledge to make project decisions and course adjustments. CTI/MDI positively impacted the project's technology development, uncovered potential technology partnerships, and supported eventual industry partner contacts. CTI/MDI analysis is now seen as due diligence and the(mu)ChemLab(trademark) project is now the model for other Sandia LDRD Grand Challenge undertakings. This document describes the CTI/MDI analysis and captures the more important ''lessons learned'' of this Grand Challenge project, as reported by the project's management team

PREDIKSI SEBARAN ASAP KEBAKARAN HUTAN/LAHAN MENGGUNAKAN WRF/CHEM (Studi Kasus: Tanggal 14 dan 20 Juni 2012, Pekanbaru-Riau

Directory of Open Access Journals (Sweden)

Eko Heriyanto

2015-01-01

Full Text Available Penelitian ini bertujuan mengembangkan prediksi sebaran asap kebakaran hutan/lahan di wilayah Indonesia. Simulasi prediksi sebaran  asap (hindcast menggunakan model Weather Research and Forecasting with CHEMistry (WRF/CHEM pada kasus kebakaran hutan/lahan tanggal 14 dan 20 Juni 2012 di wilayah Pekanbaru-Riau. Dalam penelitian ini digunakan data luaran WRF resolusi 25 km dan emisi global . Hasil simulasi  konsentrasi Carbon Monoxide (CO luaran WRF/CHEM menggambarkan pola yang identik dengan hasil luaran Monitoring Atmospheric Composition and Climate (MACC-Reanalysis 1.10. Dilakukan juga analisis kualitatif terhadap hasil simulasi kedua model dengan citra satelit Aqua-Terra MODIS, NOAA-18, dan total column CO Atmospheric Infrared Sounder (AIRS dari NASA. Korelasi simulasi kedua model menunjukkan nilai yang baik antara 0.55 – 0.83. Secara umum dapat disimpulkan bahwa WRF/CHEM mampu mensimulasikan sebaran asap kebakaran hutan/lahan secara akurat. Hasil penelitian ini bisa menjadi salah satu langkah awal dalam pengembangan sistem peringatan dini sebaran asap kebakaran hutan/lahan di wilayah Indonesia.   This study aims to develop a predictive distribution of forest fire smoke/land in the territory of Indonesia. The simulation of smoke spread prediction (hindcast is using the Weather Research and Forecasting Model with CHEMistry (WRF/CHEM in the case of forest fires/land dated June 14, 2012 in Pekanbaru-Riau region. This study uses the WRF data output resolution 25 km and global emissions. Carbon Monoxide concentration simulation results (CO which is the WRF/CHEM output describes patterns that are identical to the results of Monitoring Atmospheric Composition and Climate (MACC-Reanalysis 1.1250 outcomes. a qualitative analysis of the results of the both simulation models with satellite imagery MODIS Aqua-Terra,NOAA-18 and the Total column CO Atmospheric Infrared Sounder (Airs from NASA has  been conducted as well. Both simulation models show a

Towards a Comprehensive Dynamic-chemistry Assimilation for Eos-Chem: Plans and Status in NASA's Data Assimilation Office

Science.gov (United States)

Pawson, Steven; Lin, Shian-Jiann; Rood, Richard B.; Stajner, Ivanka; Nebuda, Sharon; Nielsen, J. Eric; Douglass, Anne R.

2000-01-01

In order to support the EOS-Chem project, a comprehensive assimilation package for the coupled chemical-dynamical system is being developed by the Data Assimilation Office at NASA GSFC. This involves development of a coupled chemistry/meteorology model and of data assimilation techniques for trace species and meteorology. The model is being developed using the flux-form semi-Lagrangian dynamical core of Lin and Rood, the physical parameterizations from the NCAR Community Climate Model, and atmospheric chemistry modules from the Atmospheric Chemistry and Dynamics branch at NASA GSFC. To date the following results have been obtained: (i) multi-annual simulations with the dynamics-radiation model show the credibility of the package for atmospheric simulations; (ii) initial simulations including a limited number of middle atmospheric trace gases reveal the realistic nature of transport mechanisms, although there is still a need for some improvements. Samples of these results will be shown. A meteorological assimilation system is currently being constructed using the model; this will form the basis for the proposed meteorological/chemical assimilation package. The latter part of the presentation will focus on areas targeted for development in the near and far terms, with the objective of Providing a comprehensive assimilation package for the EOS-Chem science experiment. The first stage will target ozone assimilation. The plans also encompass a reanalysis (ReSTS) for the 1991-1995 period, which includes the Mt. Pinatubo eruption and the time when a large number of UARS observations were available. One of the most challenging aspects of future developments will be to couple theoretical advances in tracer assimilation with the practical considerations of a real environment and eventually a near-real-time assimilation system.

Advances in molecular quantum chemistry contained in the Q-Chem 4 program package

Science.gov (United States)

Shao, Yihan; Gan, Zhengting; Epifanovsky, Evgeny; Gilbert, Andrew T. B.; Wormit, Michael; Kussmann, Joerg; Lange, Adrian W.; Behn, Andrew; Deng, Jia; Feng, Xintian; Ghosh, Debashree; Goldey, Matthew; Horn, Paul R.; Jacobson, Leif D.; Kaliman, Ilya; Khaliullin, Rustam Z.; Kuś, Tomasz; Landau, Arie; Liu, Jie; Proynov, Emil I.; Rhee, Young Min; Richard, Ryan M.; Rohrdanz, Mary A.; Steele, Ryan P.; Sundstrom, Eric J.; Woodcock, H. Lee, III; Zimmerman, Paul M.; Zuev, Dmitry; Albrecht, Ben; Alguire, Ethan; Austin, Brian; Beran, Gregory J. O.; Bernard, Yves A.; Berquist, Eric; Brandhorst, Kai; Bravaya, Ksenia B.; Brown, Shawn T.; Casanova, David; Chang, Chun-Min; Chen, Yunqing; Chien, Siu Hung; Closser, Kristina D.; Crittenden, Deborah L.; Diedenhofen, Michael; DiStasio, Robert A., Jr.; Do, Hainam; Dutoi, Anthony D.; Edgar, Richard G.; Fatehi, Shervin; Fusti-Molnar, Laszlo; Ghysels, An; Golubeva-Zadorozhnaya, Anna; Gomes, Joseph; Hanson-Heine, Magnus W. D.; Harbach, Philipp H. P.; Hauser, Andreas W.; Hohenstein, Edward G.; Holden, Zachary C.; Jagau, Thomas-C.; Ji, Hyunjun; Kaduk, Benjamin; Khistyaev, Kirill; Kim, Jaehoon; Kim, Jihan; King, Rollin A.; Klunzinger, Phil; Kosenkov, Dmytro; Kowalczyk, Tim; Krauter, Caroline M.; Lao, Ka Un; Laurent, Adèle D.; Lawler, Keith V.; Levchenko, Sergey V.; Lin, Ching Yeh; Liu, Fenglai; Livshits, Ester; Lochan, Rohini C.; Luenser, Arne; Manohar, Prashant; Manzer, Samuel F.; Mao, Shan-Ping; Mardirossian, Narbe; Marenich, Aleksandr V.; Maurer, Simon A.; Mayhall, Nicholas J.; Neuscamman, Eric; Oana, C. Melania; Olivares-Amaya, Roberto; O'Neill, Darragh P.; Parkhill, John A.; Perrine, Trilisa M.; Peverati, Roberto; Prociuk, Alexander; Rehn, Dirk R.; Rosta, Edina; Russ, Nicholas J.; Sharada, Shaama M.; Sharma, Sandeep; Small, David W.; Sodt, Alexander; Stein, Tamar; Stück, David; Su, Yu-Chuan; Thom, Alex J. W.; Tsuchimochi, Takashi; Vanovschi, Vitalii; Vogt, Leslie; Vydrov, Oleg; Wang, Tao; Watson, Mark A.; Wenzel, Jan; White, Alec; Williams, Christopher F.; Yang, Jun; Yeganeh, Sina; Yost, Shane R.; You, Zhi-Qiang; Zhang, Igor Ying; Zhang, Xing; Zhao, Yan; Brooks, Bernard R.; Chan, Garnet K. L.; Chipman, Daniel M.; Cramer, Christopher J.; Goddard, William A., III; Gordon, Mark S.; Hehre, Warren J.; Klamt, Andreas; Schaefer, Henry F., III; Schmidt, Michael W.; Sherrill, C. David; Truhlar, Donald G.; Warshel, Arieh; Xu, Xin; Aspuru-Guzik, Alán; Baer, Roi; Bell, Alexis T.; Besley, Nicholas A.; Chai, Jeng-Da; Dreuw, Andreas; Dunietz, Barry D.; Furlani, Thomas R.; Gwaltney, Steven R.; Hsu, Chao-Ping; Jung, Yousung; Kong, Jing; Lambrecht, Daniel S.; Liang, WanZhen; Ochsenfeld, Christian; Rassolov, Vitaly A.; Slipchenko, Lyudmila V.; Subotnik, Joseph E.; Van Voorhis, Troy; Herbert, John M.; Krylov, Anna I.; Gill, Peter M. W.; Head-Gordon, Martin

2015-01-01

A summary of the technical advances that are incorporated in the fourth major release of the Q-Chem quantum chemistry program is provided, covering approximately the last seven years. These include developments in density functional theory methods and algorithms, nuclear magnetic resonance (NMR) property evaluation, coupled cluster and perturbation theories, methods for electronically excited and open-shell species, tools for treating extended environments, algorithms for walking on potential surfaces, analysis tools, energy and electron transfer modelling, parallel computing capabilities, and graphical user interfaces. In addition, a selection of example case studies that illustrate these capabilities is given. These include extensive benchmarks of the comparative accuracy of modern density functionals for bonded and non-bonded interactions, tests of attenuated second order Møller-Plesset (MP2) methods for intermolecular interactions, a variety of parallel performance benchmarks, and tests of the accuracy of implicit solvation models. Some specific chemical examples include calculations on the strongly correlated Cr2 dimer, exploring zeolite-catalysed ethane dehydrogenation, energy decomposition analysis of a charged ter-molecular complex arising from glycerol photoionisation, and natural transition orbitals for a Frenkel exciton state in a nine-unit model of a self-assembling nanotube.

A four-country ring test of nontarget effects of ivermectin residues on the function of coprophilous communities of arthropods in breaking down livestock dung.

Science.gov (United States)

Tixier, Thomas; Blanckenhorn, Wolf U; Lahr, Joost; Floate, Kevin; Scheffczyk, Adam; Düring, Rolf-Alexander; Wohde, Manuel; Römbke, Jörg; Lumaret, Jean-Pierre

2016-08-01

By degrading the dung of livestock that graze on pastures, coprophilous arthropods accelerate the cycling of nutrients to maintain pasture quality. Many veterinary medicinal products, such as ivermectin, are excreted unchanged in the dung of treated livestock. These residues can be insecticidal and may reduce the function (i.e., dung-degradation) of the coprophilous community. In the present study, we used a standard method to monitor the degradation of dung from cattle treated with ivermectin. The present study was performed during a 1-yr period on pastures in Canada, France, The Netherlands, and Switzerland. Large effects of residue were detected on the coprophilous community, but degradation of dung was not significantly hampered. The results emphasize that failure to detect an effect of veterinary medicinal product residues on dung-degradation does not mean that the residues do not affect the coprophilous community. Rather, insect activity is only one of many factors that affect degradation, and these other factors may mask the nontarget effect of residues. Environ Toxicol Chem 2016;35:1953-1958. © 2015 SETAC. © 2015 SETAC.

Alternative approaches to vertebrate ecotoxicity tests in the 21st century: A review of developments over the last 2 decades and current status.

Science.gov (United States)

Lillicrap, Adam; Belanger, Scott; Burden, Natalie; Pasquier, David Du; Embry, Michelle R; Halder, Marlies; Lampi, Mark A; Lee, Lucy; Norberg-King, Teresa; Rattner, Barnett A; Schirmer, Kristin; Thomas, Paul

2016-11-01

The need for alternative approaches to the use of vertebrate animals for hazard assessment of chemicals and pollutants has become of increasing importance. It is now the first consideration when initiating a vertebrate ecotoxicity test, to ensure that unnecessary use of vertebrate organisms is minimized wherever possible. For some regulatory purposes, the use of vertebrate organisms for environmental risk assessments has been banned; in other situations, the number of organisms tested has been dramatically reduced or the severity of the procedure refined. However, there is still a long way to go to achieve a complete replacement of vertebrate organisms to generate environmental hazard data. The development of animal alternatives is based not just on ethical considerations but also on reducing the cost of performing vertebrate ecotoxicity tests and in some cases on providing better information aimed at improving environmental risk assessments. The present Focus article provides an overview of the considerable advances that have been made toward alternative approaches for ecotoxicity assessments over the last few decades. Environ Toxicol Chem 2016;35:2637-2646. © 2016 SETAC. © 2016 SETAC.

iNR-PhysChem: a sequence-based predictor for identifying nuclear receptors and their subfamilies via physical-chemical property matrix.

Directory of Open Access Journals (Sweden)

Xuan Xiao

Full Text Available Nuclear receptors (NRs form a family of ligand-activated transcription factors that regulate a wide variety of biological processes, such as homeostasis, reproduction, development, and metabolism. Human genome contains 48 genes encoding NRs. These receptors have become one of the most important targets for therapeutic drug development. According to their different action mechanisms or functions, NRs have been classified into seven subfamilies. With the avalanche of protein sequences generated in the postgenomic age, we are facing the following challenging problems. Given an uncharacterized protein sequence, how can we identify whether it is a nuclear receptor? If it is, what subfamily it belongs to? To address these problems, we developed a predictor called iNR-PhysChem in which the protein samples were expressed by a novel mode of pseudo amino acid composition (PseAAC whose components were derived from a physical-chemical matrix via a series of auto-covariance and cross-covariance transformations. It was observed that the overall success rate achieved by iNR-PhysChem was over 98% in identifying NRs or non-NRs, and over 92% in identifying NRs among the following seven subfamilies: NR1--thyroid hormone like, NR2--HNF4-like, NR3--estrogen like, NR4--nerve growth factor IB-like, NR5--fushi tarazu-F1 like, NR6--germ cell nuclear factor like, and NR0--knirps like. These rates were derived by the jackknife tests on a stringent benchmark dataset in which none of protein sequences included has ≥60% pairwise sequence identity to any other in a same subset. As a user-friendly web-server, iNR-PhysChem is freely accessible to the public at either http://www.jci-bioinfo.cn/iNR-PhysChem or http://icpr.jci.edu.cn/bioinfo/iNR-PhysChem. Also a step-by-step guide is provided on how to use the web-server to get the desired results without the need to follow the complicated mathematics involved in developing the predictor. It is anticipated that iNR-PhysChem may

ConfChem Conference on Flipped Classroom: Using a Blog to Flip a Classroom

Science.gov (United States)

Haile, January D.

2015-01-01

This communication summarizes one of the invited papers to the Flipped Classroom ACS Division of Chemical Education Committee on Computers in Chemical Education online ConfChem held from May 18 to June 24, 2014. Just in Time Teaching is a technique in which students read the material before class and respond to a few questions. In a first-year…

Threshold of toxicological concern values for non-genotoxic effects in industrial chemicals: re-evaluation of the Cramer classification.

Science.gov (United States)

Kalkhof, H; Herzler, M; Stahlmann, R; Gundert-Remy, U

2012-01-01

The TTC concept employs available data from animal testing to derive a distribution of NOAELs. Taking a probabilistic view, the 5th percentile of the distribution is taken as a threshold value for toxicity. In this paper, we use 824 NOAELs from repeated dose toxicity studies of industrial chemicals to re-evaluate the currently employed TTC values, which have been derived for substances grouped according to the Cramer scheme (Cramer et al. in Food Cosm Toxicol 16:255-276, 1978) by Munro et al. (Food Chem Toxicol 34:829-867, 1996) and refined by Kroes and Kozianowski (Toxicol Lett 127:43-46, 2002), Kroes et al. 2000. In our data set, consisting of 756 NOAELs from 28-day repeated dose testing and 57 NOAELs from 90-days repeated dose testing, the experimental NOAEL had to be extrapolated to chronic TTC using regulatory accepted extrapolation factors. The TTC values derived from our data set were higher than the currently used TTC values confirming the safety of the latter. We analysed the prediction of the Cramer classification by comparing the classification by this tool with the guidance values for classification according to the Globally Harmonised System of classification and labelling of the United Nations (GHS). Nearly 90% of the chemicals were in Cramer class 3 and assumed as highly toxic compared to 22% according to the GHS. The Cramer classification does underestimate the toxicity of chemicals only in 4.6% of the cases. Hence, from a regulatory perspective, the Cramer classification scheme might be applied as it overestimates hazard of a chemical.

E-chem page: A Support System for Remote Diagnosis of Water Quality in Boiling Water Reactors

International Nuclear Information System (INIS)

Naohiro Kusumi; Takayasu Kasahara; Kazuhiko Akamine; Kenji Tada; Naoshi Usui; Nobuyuki Oota

2002-01-01

It is important to control and maintain water quality for nuclear power plants. Chemical engineers sample and monitor reactor water from various subsystems and analyze the chemical quality as routine operations. With regard to controlling water quality, new technologies have been developed and introduced to improve the water quality from both operation and material viewpoints. To maintain the quality, it is important to support chemical engineers in evaluating the water quality and realizing effective retrieval of stored data and documents. We have developed a remote support system using the Internet to diagnose BWR water quality, which we call e-chem page. The e-chem page integrates distributed data and information in a Web server, and makes it easy to evaluate the data on BWR water chemistry. This system is composed of four functions: data transmission, water quality evaluation, inquiry and history retrieval system, and reference to documents on BWR water chemistry. The developed system is now being evaluated in trial operations by Hitachi, Ltd. and an electric power company. In addition diagnosis technology applying independent component analysis (ICA) is being developed to improve predictive capability of the system. This paper describes the structure and function of the e-chem page and presents results of obtained with the proposed system for the prediction of chemistry conditions in reactor water. (authors)

Air Quality Modeling for the Urban Jackson, Mississippi Region Using a High Resolution WRF/Chem Model

Directory of Open Access Journals (Sweden)

Shelton J. Swanier

2011-06-01

Full Text Available In this study, an attempt was made to simulate the air quality with reference to ozone over the Jackson (Mississippi region using an online WRF/Chem (Weather Research and Forecasting–Chemistry model. The WRF/Chem model has the advantages of the integration of the meteorological and chemistry modules with the same computational grid and same physical parameterizations and includes the feedback between the atmospheric chemistry and physical processes. The model was designed to have three nested domains with the inner-most domain covering the study region with a resolution of 1 km. The model was integrated for 48 hours continuously starting from 0000 UTC of 6 June 2006 and the evolution of surface ozone and other precursor pollutants were analyzed. The model simulated atmospheric flow fields and distributions of NO2 and O3 were evaluated for each of the three different time periods. The GIS based spatial distribution maps for ozone, its precursors NO, NO2, CO and HONO and the back trajectories indicate that all the mobile sources in Jackson, Ridgeland and Madison contributing significantly for their formation. The present study demonstrates the applicability of WRF/Chem model to generate quantitative information at high spatial and temporal resolution for the development of decision support systems for air quality regulatory agencies and health administrators.

PubChemQC Project: A Large-Scale First-Principles Electronic Structure Database for Data-Driven Chemistry.

Science.gov (United States)

Nakata, Maho; Shimazaki, Tomomi

2017-06-26

Large-scale molecular databases play an essential role in the investigation of various subjects such as the development of organic materials, in silico drug design, and data-driven studies with machine learning. We have developed a large-scale quantum chemistry database based on first-principles methods. Our database currently contains the ground-state electronic structures of 3 million molecules based on density functional theory (DFT) at the B3LYP/6-31G* level, and we successively calculated 10 low-lying excited states of over 2 million molecules via time-dependent DFT with the B3LYP functional and the 6-31+G* basis set. To select the molecules calculated in our project, we referred to the PubChem Project, which was used as the source of the molecular structures in short strings using the InChI and SMILES representations. Accordingly, we have named our quantum chemistry database project "PubChemQC" ( http://pubchemqc.riken.jp/ ) and placed it in the public domain. In this paper, we show the fundamental features of the PubChemQC database and discuss the techniques used to construct the data set for large-scale quantum chemistry calculations. We also present a machine learning approach to predict the electronic structure of molecules as an example to demonstrate the suitability of the large-scale quantum chemistry database.

Single and combined effects of microcystin- and saxitoxin-producing cyanobacteria on the fitness and antioxidant defenses of cladocerans.

Science.gov (United States)

da S Ferrão-Filho, Aloysio; de Abreu S Silva, Daniel; de Oliveira, Taissa A; de Magalhães, Valéria Freitas; Pflugmacher, Stephan; da Silva, Eduardo Mendes

2017-10-01

Cyanobacteria produce different toxic compounds that affect animal life, among them hepatotoxins and neurotoxins. Because cyanobacteria are able to produce a variety of toxic compounds at the same time, organisms may be, generally, subjected to their combined action. In the present study, we demonstrate the single and combined effects on cladocerans of cyanobacteria that produce microcystins (hepatotoxins) and saxitoxins (neurotoxins). Animals were exposed (either singly or combined) to 2 strains of cyanobacteria isolated from the same environment (Funil Reservoir, Rio de Janeiro, Brazil). The effects on clearance rate, mobility, survivorship, fecundity, population increase rate (r), and the antioxidant enzymes glutathione-S-transferase (GST) and catalase (CAT) were measured. Cladoceran species showed a variety of responses to cyanobacterial exposures, going from no effect to impairment of swimming movement, lower survivorship, fecundity, and general fitness (r). Animals ingested cyanobacteria in all treatments, although at lower rates than good food (green algae). Antioxidant defense responses were in accordance with fitness responses, suggesting that oxidative stress may be related to such effects. The present study emphasizes the need for testing combined actions of different classes of toxins, because this is often, and most likely, the scenario in a more eutrophic world with global climatic changes. Environ Toxicol Chem 2017;36:2689-2697. © 2017 SETAC. © 2017 SETAC.

ChemCam at Gale Crater: Highlights and Discoveries from Three Years of Chemical Measurements on Mars

Science.gov (United States)

Blaney, Diana L.; Wiens, Roger; Maurice, Sylvestre; Gasnault, Olivier; Anderson, Ryan; Bridges, John; Bridges, Nathan; Clegg, Samuel; Clark, Benton; Ehlmann, Bethany; Dyar, Melinda D.; Fisk, Martin; Francis, Raymond; Fabre, Cecile; Forni, Olivier; Frydenvang, Jens; Johnson, Jeffery; Lanza, Nina; Leveille, Richard; Lasue, Jeremie; Le Deit, Laetitia; Mangold, Nicholas; Melikechi, Noureddine; Nachon, Marion; Newsom, Horton; Payre, Valerie; Rapin, William; Sautter, Violane; Vaniman, David; Grotzinger, John; Vasavad, Ashwin; Crisp, Joy

2015-11-01

ChemCam has undertaken a detailed chemical investigation of the rocks and soils at Gale crater over the last three years with over six thousand separate geochemical measurements. Recent recalibration of the ChemCam data using a new library of >350 geochemical standards has enabled increased elemental accuracies over a wider compositional range. The increased accuracy combined with ChemCam’s small spot size allows for the chemistry of mineral end members including feldspars, high silica, oxide rich grains to be identified. ChemCam has observed both sedimentary and igneous compositions. Igneous compositions are generally present in conglomerates and in float rocks. Compositions show a wide range of igneous chemistry ranging from basaltic to feldspar rich assemblages.Sedimentary rocks have a wide range of compositions reflecting both differences in chemical source regions and in depositional and diagenetic histories. The “Sheepbed” mudstones cluster around Martian average crustal compositions. The “Kimberley” outcrop showed enhanced potassium reaching concentrations up to ~6 wt% K2O. More recent observations in the Murray Formation at the base of Mt. Sharp reveal mudstones that are lower in magnesium and higher in silica and aluminum than the more basaltic mudstones previously investigated. Extremely high silica (75-85 wt%) deposits have also been identified. The high silica observations were associated with increased TiO2, While the Murray mudstones are generally low in magnesium, local enhancements in magnesium have also been noted associated with resistant facies in the outcrop. Chemical trends also indicate that iron oxide phases may also be present as cements. Sandstone facies with a mafic composition are also present. Veins in the unit also show a wide range of compositions indicating fluid chemistries rich in calcium sulfate, fluorine, magnesium and iron were present. Vein chemistry could be the result of distinct fluids migrating through from a

Calibration of the Fluorine, Chlorine and Hydrogen Content of Apatites With the ChemCam LIBS Instrument

Science.gov (United States)

Meslin, P.-Y.; Cicutto, L.; Forni, O.; Drouet, C.; Rapin, W.; Nachon, M.; Cousin, A.; Blank, J. G.; McCubbin, F. M.; Gasnault, O.;

Comparative safety testing of genetically modified foods in a 90-day rat feeding study design allowing the distinction between primary and secondary effects of the new genetic event.

Science.gov (United States)

Knudsen, Ib; Poulsen, Morten

2007-10-01

This article discusses the wider experiences regarding the usefulness of the 90-day rat feeding study for the testing of whole foods from genetically modified (GM) plant based on data from a recent EU-project [Poulsen, M., Schrøder, M., Wilcks, A., Kroghsbo, S., Lindecrona, R.H., Miller, A., Frenzel, T., Danier, J., Rychlik, M., Shu, Q., Emami, K., Taylor, M., Gatehouse, A., Engel, K.-H., Knudsen, I., 2007a. Safety testing of GM-rice expressing PHA-E lectin using a new animal test design. Food Chem. Toxicol. 45, 364-377; Poulsen, M., Kroghsbo, S., Schrøder, M., Wilcks, A., Jacobsen, H., Miller, A., Frenzel, T., Danier, J., Rychlik, M., Shu, Q., Emami, K., Sudhakar, D., Gatehouse, A., Engel, K.-H., Knudsen, I., 2007b. A 90-day safety in Wistar rats fed genetically modified rice expressing snowdrop lectin Galanthus nivalis (GNA). Food Chem. Toxicol. 45, 350-363; Schrøder, M., Poulsen, M., Wilcks, A., Kroghsbo, S., Miller, A., Frenzel, T., Danier, J., Rychlik, M., Emami, K., Gatehouse, A., Shu, Q., Engel, K.-H., Knudsen, I., 2007. A 90-day safety study of genetically modified rice expressing Cry1Ab protein (Bacillus thuringiensis toxin) in Wistar rats. Food Chem. Toxicol. 45, 339-349]. The overall objective of the project has been to develop and validate the scientific methodology necessary for assessing the safety of foods from genetically modified plants in accordance with the present EU regulation. The safety assessment in the project is combining the results of the 90-day rat feeding study on the GM food with and without spiking with the pure novel gene product, with the knowledge about the identity of the genetic change, the compositional data of the GM food, the results from in-vitro/ex-vivo studies as well as the results from the preceding 28-day toxicity study with the novel gene product, before the hazard characterisation is concluded. The results demonstrated the ability of the 90-day rat feeding study to detect the biological/toxicological effects of the

Visible and Near-Infrared (VNIR) Spectroscopy of Altered Basalts with Application to the ChemCam Library for Mars Science Laboratory

Science.gov (United States)

Hadnott, B.; Ehlmann, B. L.

2012-12-01

The discovery of Fe, Mg, and Al clays on Mars using VNIR spectroscopy from orbit indicates past low temperature/pressure hydrothermal and weathering environments. Laboratory analysis of Mars-analog rocks from these settings on Earth was used to build the ChemCam sample library for Mars Science Laboratory, permitting for more accurate compositional analysis of Martian samples, improved linkages between VNIR's mineralogic and ChemCam's elemental data, and improved recognition of different environmental settings for aqueous alteration. VNIR spectroscopy was used to analyze 4 suites of altered basaltic rocks—one from San Carlos, AZ and three from various locations in Iceland. Continuum shape and absorption features were found to vary, depending on the environment and extent of alteration. Relatively unaltered rocks had electronic absorptions related to ferrous iron. The strength of the 1.9- μm (μm = microns) H2O absorption correlated with the degree of aqueous alteration. Samples with strong 1.9- μm absorptions often exhibited absorption bands at 1.4, 2.2, and 2.3 μm indicating the presence of clay minerals and/or features at 0.5-0.8 μm indicative of ferric iron oxides. Diagnostic absorption features and continuum slopes have been used to identify a representative subset of rocks from each suite for further analysis for the ChemCam library. Noteworthy spectral features for all suites included variation of absorption bands from 2.0-2.5 μm. Most samples contained an absorption band near 2.21 μm, indicating the presence of Si-OH or Al-OH; a 2.3 μm band is also present in some samples, indicating the presence of Mg-OH and Fe-OH, with subtle shifts between 2.29 and 2.35 μm indicating the major cation and constituent phase (e.g. amorphous phase, smectite or chlorite). Overall continuum slope correlated with the degree of alteration. Flat slopes contained weak 1.9 μm bands (little alteration) and sometimes ferrous iron absorptions of primary minerals. Negative

The Chem-E-Car as a Vehicle for Service Learning through K-12 Outreach

Science.gov (United States)

Chirdon, William

2017-01-01

This article presents the results of combining the American Institute of Chemical Engineers' (AIChE) Chem-E-Car competition activities with engineering outreach to K-12 students in a service-learning course. Survey results are presented to show how the program develops technical skills as well as leadership, teamwork, and communication skills in…

Rozhovor s Jiřím Poláchem a Michaelou Záluskou z Knihovny ÚOCHB

Czech Academy of Sciences Publication Activity Database

Burešová, Iva

2-3 (2016) E-ISSN 1805-2800 Keywords : interview * Institute of Organic Chemistry and Biochemistry of the CAS * library tramformation * chemLib https://www.lib.cas.cz/casopis-informace/knihovna-uochb/

Avaliação dos Efeitos Toxicológicos e Ambientais de Nanopartículas de Sais de Prata

Directory of Open Access Journals (Sweden)

Francielle Tatiana Mathias

2014-01-01

Full Text Available As nanopartículas de sais de prata são compostos muito utilizados nas indústrias farmacêuticas e de cosméticos, além de seu uso hospitalar. Sua utilização, tanto em produtos comerciais como na medicina, e sua importante correlação com a saúde pública e meio ambiente despertaram grande interesse em ações diretas e indiretas sobre o ser humano. Particularmente as nanopartículas de sais de prata têm sido muito utilizadas como antimicrobianos na desinfecção de materiais hospitalares, desodorantes, materiais dentários, em próteses internas e cateteres intravenosos, e tem possibilitado a contaminação humana e ambiental. Seus efeitos, concentrações perigosas e valores aceitáveis como contaminante demandam estudos. Sua instabilidade frente a interações com outros produtos as torna de grande interesse em relação à contaminação e persistência no ambiente. Diversos trabalhos produzidos em nossos laboratórios demonstram a atividade desreguladora endócrina de vários produtos químicos contaminantes ambientais e prejudiciais à saúde humana. Deste modo buscou-se um levantamento das principais formas de uso, seus riscos e efeitos toxicológicos para a saúde pública e meio ambiente.

ChemSession'09 - 6. Warsaw Seminar of the PhD Students in Chemistry - Abstracts

International Nuclear Information System (INIS)

2009-01-01

Book of Abstracts contains short descriptions of presentations 3 lectures and 105 posters presented during ChemSession'09 - 6 th Warsaw Seminar of the PhD Students in Chemistry. Several posters were devoted to the radiochemistry, radiochemical analysis, radiation chemistry and radiobiology. Some posters on the material science dealing with materials important to nuclear sciences can be also found

ChemSkill Builder 2000, Version 6.1 [CD-ROM] (by James D. Spain and Harold J. Peters)

Science.gov (United States)

Keeney-Kennicutt, Reviewed By Wendy L.

2000-07-01

One of the major challenges for faculty teaching general chemistry is how to encourage students to practice solving problems. We know that for students to develop chemical intuition and problem-solving skills, they must "get their hands dirty" as they decipher and unravel problems inherent to our discipline. One tool that I've used since its release in 1996 is the ChemSkill Builder, an electronic homework package. The latest version, ChemSkill Builder (CSB) 2000, version 6.1, is an excellent, effective integration of teaching and testing most quantitative and conceptual learning objectives in an interactive way. It is inexpensive and easy to use for both students and faculty. The CSB 2000 package of personalized problem sets, specifically designed to complement most general chemistry courses, is a program on CD-ROM for PC Windows users (3.1, 95, or 98), with more than 1500 questions and a 3 1/2-in. record-management disk. There is a separate grade-management disk for the instructor. It has 24 gradable chapters, each with 5 or 6 sections, plus two new chapters that are not graded: Polymer Chemistry and an Appendix of Chemical Skills. Each section begins with a short review of the topic and many have interactive explanations. If students miss an answer, they are given a second chance for 70% credit. If they still miss, the worked-out solution is presented in detail. Students can work each section as many times as they wish to improve their scores. Periodically, the students download their data directly into a PC set up by the instructor. The data can be easily converted into an ASCII file and merged with a spreadsheet. The use of CD-ROM solves the sporadic problems associated with previous versions on 3 1/2-in. disks: software glitches, failed disks, and system incompatibilities. The quality and number of graphics and interactive exercises are much improved in this latest version. I particularly enjoyed the interactive explanations of significant figures and

Correcting for variable laser-target distances of laser-induced breakdown spectroscopy measurements with ChemCam using emission lines of Martian dust spectra

Energy Technology Data Exchange (ETDEWEB)

Melikechi, N.; Mezzacappa, A. [Optical Science Center for Applied Research, Delaware State University, Dover, DE (United States); Cousin, A.; Lanza, N.L. [Los Alamos National Laboratory, Los Alamos, NM (United States); Lasue, J. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Clegg, S.M. [Los Alamos National Laboratory, Los Alamos, NM (United States); Berger, G. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Wiens, R.C. [Los Alamos National Laboratory, Los Alamos, NM (United States); Maurice, S. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Tokar, R.L.; Bender, S. [Planetary Science Institute, Flagstaff, AZ (United States); Forni, O. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Breves, E.A.; Dyar, M.D. [Dept. of Astronomy, Mount Holyoke College, South Hadley, MA (United States); Frydenvang, J. [The Niels Bohr Institute, University of Copenhagen, Copenhagen (Denmark); Delapp, D. [Los Alamos National Laboratory, Los Alamos, NM (United States); Gasnault, O. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Newsom, H.; Ollila, A.M. [Earth and Planetary Sciences, University of New Mexico, Alburquerque, NM (United States); Lewin, E. [Institut des Sciences de la Terre, Universite Grenoble l-CNRS, Grenoble (France); and others

2014-06-01

As part of the Mars Science Laboratory, the ChemCam instrument acquires remote laser induced breakdown spectra at distances that vary between 1.56 m and 7 m. This variation in distance affects the intensities of the measured LIBS emission lines in non-trivial ways. To determine the behavior of a LIBS emission line with distance, it is necessary to separate the effects of many parameters such as laser energy, laser spot size, target homogeneity, and optical collection efficiency. These parameters may be controlled in a laboratory on Earth but for field applications or in space this is a challenge. In this paper, we show that carefully selected ChemCam LIBS emission lines acquired from the Martian dust can be used to build an internal proxy spectroscopic standard. This in turn, allows for a direct measurement of the effects of the distance of various LIBS emission lines and hence can be used to correct ChemCam LIBS spectra for distance variations. When tested on pre-launch LIBS calibration data acquired under Martian-like conditions and with controlled and well-calibrated targets, this approach yields much improved agreement between targets observed at various distances. This work lays the foundation for future implementation of automated routines to correct ChemCam spectra for differences caused by variable distance. - Highlights: • Selected Martian dust emission lines are used to correct for variable laser-target distances. • The correction model yields improved agreement between targets observed at various distances. • The impact of the model reduces the bias between predicted and actual compositions by as much as 70%. • When implemented, the model will yield spectral corrections for various ChemCam measurements. • This work is a foundation to perform novel stand-off LIBS measurements on Earth and other planets.

ChemSession'08 - 5. Warsaw Seminar of the PhD Students in Chemistry - Abstracts

International Nuclear Information System (INIS)

Madura, I.

2008-01-01

Book of Abstracts consists of short descriptions of presentations: 5 lectures and 127 posters presented during ChemSession'08 - 5 th Warsaw Seminar of the PhD Students in Chemistry. Several posters were devoted to the radiochemistry, radiochemical analysis, radiation chemistry and radiobiology. Some posters on the material science dealing with materials important to nuclear sciences can be also found

Mixed Waste Treatment Using the ChemChar Thermolytic Detoxification Technique

International Nuclear Information System (INIS)

Kuchynka, D.J.

1997-01-01

This R and D program addresses the treatment of mixed waste employing the ChemChar Thermolytic Detoxification process. Surrogate mixed waste streams will be treated in a four inch diameter, continuous feed, adiabatic reactor with the goal of meeting all regulatory treatment levels for the contaminants in the surrogates with the concomitant production of contaminant free by-products. Successful completion of this program will show that organic contaminants in mixed waste surrogates will be converted to a clean, energy rich synthesis gas capable of being used, without further processing, for power or heat generation. The inorganic components in the surrogates will be found to be adsorbed on a macroporous coal char activated carbon substrate which is mixed with the waste prior to treatment. These contaminants include radioactive metal surrogate species, RCRA hazardous metals and any acid gases formed during the treatment process. The program has three main tasks that will be performed to meet the above objectives. The first task is the design and construction of the four inch reactor at Mirage Systems in Sunnyvale, CA. The second task is production and procurement of the activated carbon char employed in the ChemChartest runs and identification of two surrogate mixed wastes. The last task is testing and operation of the reactor on char/surrogate waste mixtures to be performed at the University of Missouri. The deliverables for the project are a Design Review Report, Operational Test Plan, Topical Report and Final Report. This report contains only the results of the design and construction carbon production-surrogate waste identification tasks.Treatment of the surrogate mixed wastes has just begun and will not be reported in this version of the Final Report. The latter will be reported in the final version of the Final Report

Leveraging a large scale mammalian pharmacological dataset to prioritize potential environmental hazard of pharmaceuticals

Science.gov (United States)

The potential for pharmaceuticals in the environment to cause adverse ecological effects is of increasing concern. Given the thousands of active pharmaceutical ingredients (APIs) which can enter the aquatic environment through various means, a current challenge in aquatic toxicol...

Regional Modeling of Dust Mass Balance and Radiative Forcing over East Asia using WRF-Chem

Energy Technology Data Exchange (ETDEWEB)

Chen, Siyu; Zhao, Chun; Qian, Yun; Leung, Lai-Yung R.; Huang, J.; Huang, Zhongwei; Bi, Jianrong; Zhang, Wu; Shi, Jinsen; Yang, Lei; Li, Deshuai; Li, Jinxin

2014-12-01

The Weather Research and Forecasting model with Chemistry (WRF-Chem) is used to investigate the seasonal and annual variations of mineral dust over East Asia during 2007-2011, with a focus on the dust mass balance and radiative forcing. A variety of measurements from in-stu and satellite observations have been used to evaluate simulation results. Generally, WRF-Chem reproduces not only the column variability but also the vertical profile and size distribution of mineral dust over and near the dust source regions of East Asia. We investigate the dust lifecycle and the factors that control the seasonal and spatial variations of dust mass balance and radiative forcing over the seven sub-regions of East Asia, i.e. source regions, the Tibetan Plateau, Northern China, Southern China, the ocean outflow region, and Korea-Japan regions. Results show that, over the source regions, transport and dry deposition are the two dominant sinks. Transport contributes to ~30% of the dust sink over the source regions. Dust results in a surface cooling of up to -14 and -10 W m-2, atmospheric warming of up to 20 and 15 W m-2, and TOA cooling of -5 and -8 W m-2 over the two major dust source regions of East Asia, respectively. Over the Tibetan Plateau, transport is the dominant source with a peak in summer. Over identified outflow regions, maximum dust mass loading in spring is contributed by the transport. Dry and wet depositions are the comparably dominant sinks, but wet deposition is larger than dry deposition over the Korea-Japan region, particularly in spring (70% versus 30%). The WRF-Chem simulations can generally capture the measured features of dust aerosols and its radaitve properties and dust mass balance over East Asia, which provides confidence for use in further investigation of dust impact on climate over East Asia.

ChemSession'10: 7. Warsaw Seminar of the PhD Students in Chemistry. Abstracts

International Nuclear Information System (INIS)

Madura, I.

2010-01-01

Book of Abstracts contains short descriptions of presentations 4 lectures and 151 posters presented during ChemSession'10 - 7 th Warsaw Seminar of the PhD Students in Chemistry (Warsaw, 14.05.2010). Several posters were devoted to the radiochemistry, radiochemical analysis, radiation chemistry, application of the radionuclides and radiobiology. Some posters on the material science dealing with materials important to nuclear sciences can be also mentioned.

Characterization of quality of sediments from Paranaguá Bay (Brazil) by combined in vitro bioassays and chemical analyses.

Science.gov (United States)

Rizzi, Juliane; Pérez-Albaladejo, Elisabet; Fernandes, Denise; Contreras, Javier; Froehner, Sandro; Porte, Cinta

2017-07-01

The present study characterizes the quality of sediments from the Paranaguá Estuarine Complex (South Brazil). Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) were determined in sediment samples together with a series of different in vitro bioassays. The fish hepatoma cell line (PLHC-1) was used to determine the presence of cytotoxic compounds and CYP1A- and oxidative stress-inducing agents in sediment extracts. Ovarian microsomal fractions from sea bass (Dicentrarchus labrax) were used to detect the presence of endocrine disrupters that interfered with the synthesis of estrogens (ovarian CYP19). Despite the relatively low levels of pollutants and no evidence of negative effects based on guideline levels, sediments collected close to harbors were enriched with CYP1A-inducing agents and they showed higher cytotoxicity. In contrast, sediments from internal areas inhibited CYP19 activity, which suggests the presence of endocrine disrupters at these sites. Overall, the selected bioassays and the chemistry data led to the identification of potentially impacted areas along the Paranaguá Estuarine Complex that would require further action to improve their environmental quality. Environ Toxicol Chem 2017;36:1811-1819. © 2016 SETAC. © 2016 SETAC.

Spatial and temporal trends of poly- and perfluoroalkyl substances in fish fillets and water collected from pool 2 of the Upper Mississippi River.

Science.gov (United States)

Newsted, John L; Holem, Ryan; Hohenstein, Gary; Lange, Cleston; Ellefson, Mark; Reagen, William; Wolf, Susan

2017-11-01

In 2011, poly- and perfluoroalkyl substances (PFASs) were analyzed in surface water and fish fillet samples taken from Pool 2 of the Upper Mississippi River, a 33-mile stretch inclusive of the Minneapolis/St. Paul, Minnesota (USA) metropolitan area. Approximately 100 each of bluegill, freshwater drum, smallmouth bass, and white bass were sampled within the study area. Surface water samples were also collected from each of the 10 sampling reaches established for the study. Water and fillet samples were analyzed for perfluorinated carboxylic acids (C4-C12), perfluorinated sulfonic acids (C4, C6, and C8), and perfluorooctane sulfonamide. Perfluorooctane sulfonate (PFOS) was observed with the greatest frequency in fish fillets and ranged from 3.0 to 760 ng/g wet weight. Mean (geometric) PFOS concentrations in bluegill, freshwater drum, smallmouth bass, and white bass were 20, 28, 29, and 58 ng/g wet weight, respectively. When compared with fish data collected in 2009, a significant reduction (p fish PFOS concentrations are consistent with ongoing efforts to effectively control sources of PFASs to the Mississippi River. Environ Toxicol Chem 2017;36:3138-3147. © 2017 SETAC. © 2017 SETAC.

Risk profile and health vulnerability of female workers who pick cotton by organanochlorine pesticides from southern Punjab, Pakistan.

Science.gov (United States)

Yasmeen, Humaira; Qadir, Abdul; Mumtaz, Mehvish; Eqani, Syed Ali Musstjab Akber Shah; Syed, Jabbir Hussain; Mahmood, Adeel; Jamil, Nadia; Nazar, Farva; Ali, Habib; Ahmad, Muhammad Shafiq; Tanveer, Zafar Iqbal; Zhang, Gan

2017-05-01

The present study was conducted to highlight the existing level of organochlorine-pesticides (OCPs) from human milk (n = 45) and blood serum (n = 40) of female workers who pick cotton in Khanewal District, southern Punjab, Pakistan. Source apportionment, congener-specific analysis, and risk surveillance of OCPs are reported from human milk and blood samples. Levels of OCPs in milk and blood serum samples ranged from 15.7 ppb to 538.3 ppb and from 16.4 ppb to 747.1 ppb, respectively, and were lower than previously published reports from other regions of the globe. Congener-specific analysis revealed that DDTs were predominant, followed by hexachlorocyclohexane, chlordane, and hexachlorobenzene. Calculated results for source apportionment analysis suggested that contamination load was a new input of DDTs as well as the historic use of lindane in the study area. Levels of OCPs in milk and blood serum were significantly (p risk revealed that female workers had risk of cancer among 1 per million; however, noncarcinogenic risks were not considerable. Environ Toxicol Chem 2017;36:1193-1201. © 2016 SETAC. © 2016 SETAC.

An analysis of lethal and sublethal interactions among type I and type II pyrethroid pesticide mixtures using standard Hyalella azteca water column toxicity tests.

Science.gov (United States)

Hoffmann, Krista Callinan; Deanovic, Linda; Werner, Inge; Stillway, Marie; Fong, Stephanie; Teh, Swee

2016-10-01

A novel 2-tiered analytical approach was used to characterize and quantify interactions between type I and type II pyrethroids in Hyalella azteca using standardized water column toxicity tests. Bifenthrin, permethrin, cyfluthrin, and lambda-cyhalothrin were tested in all possible binary combinations across 6 experiments. All mixtures were analyzed for 4-d lethality, and 2 of the 6 mixtures (permethrin-bifenthrin and permethrin-cyfluthrin) were tested for subchronic 10-d lethality and sublethal effects on swimming motility and growth. Mixtures were initially analyzed for interactions using regression analyses, and subsequently compared with the additive models of concentration addition and independent action to further characterize mixture responses. Negative interactions (antagonistic) were significant in 2 of the 6 mixtures tested, including cyfluthrin-bifenthrin and cyfluthrin-permethrin, but only on the acute 4-d lethality endpoint. In both cases mixture responses fell between the additive models of concentration addition and independent action. All other mixtures were additive across 4-d lethality, and bifenthrin-permethrin and cyfluthrin-permethrin were also additive in terms of subchronic 10-d lethality and sublethal responses. Environ Toxicol Chem 2016;35:2542-2549. © 2016 SETAC. © 2016 SETAC.

Effects of dietary exposure of polycyclic musk HHCB on the metamorphosis of Xenopus laevis.

Science.gov (United States)

Pablos, María Victoria; Jiménez, María Ángeles; San Segundo, Laura; Martini, Federica; Beltrán, Eulalia; Fernández, Carlos

2016-06-01

The compound 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-[γ]-2-benzopyrane (HHCB; galaxolide, Chemical Abstracts Service number 1222-05-5) is a synthetic musk used extensively as a fragrance in many consumer products and classified as an emerging pollutant. The ecotoxicological information available for HHCB addresses exposure via water, but this compound is frequently adsorbed into particulate matter. The goal of the present study was to assess the effects of dietary exposure to several environmentally relevant HHCB concentrations adsorbed in food during Xenopus laevis metamorphosis. The authors sought to determine if such exposure to this synthetic musk resulted in histological changes in the thyroid gland in conjunction with changes in development (staging, timing to metamorphosis), body weight, and length. Developmental acceleration on day 14, together with hypertrophy of the thyroid follicular epithelium in tadpoles, suggested a possible agonistic effect of HHCB, which would have been compensated after metamorphosis by regulatory mechanisms to maintain homeostasis. Further research into the potential thyroid-related mechanisms of action of HHCB should be conducted. Environ Toxicol Chem 2016;35:1428-1435. © 2015 SETAC. © 2015 SETAC.

Effects of exposure to winter oilseed rape grown from thiamethoxam-treated seed on the red mason bee Osmia bicornis.

Science.gov (United States)

Ruddle, Natalie; Elston, Charlotte; Klein, Olaf; Hamberger, Anja; Thompson, Helen

2018-04-01

There has been increasing interest in the effects of neonicotinoid insecticides on wild bees. In solitary bee species the direct link between each individual female and reproductive success offers the opportunity to evaluate effects on individuals. The present study investigated effects of exposure to winter oilseed rape grown from thiamethoxam-treated seed on reproductive behavior and output of solitary red mason bees (Osmia bicornis) released in 6 pairs of fields over a 2-yr period and confined to tunnels in a single year. After adjustment to the number of females released, there was significantly lower production of cells and cocoons/female in tunnels than in open field conditions. This difference may be because of the lack of alternative forage within the tunnels. Under open field conditions, palynology of the pollen provisions within the nests demonstrated a maximum average of 31% oilseed rape pollen at any site, with Quercus (oak) contributing up to 86% of the pollen. There were no significant effects from exposure to oilseed rape grown from thiamethoxam-treated seed from nest establishment through cell production to emergence under tunnel or field conditions. Environ Toxicol Chem 2018;37:1071-1083. © 2017 SETAC. © 2017 SETAC.

Application of WRF/Chem over East Asia: Part I. Model evaluation and intercomparison with MM5/CMAQ

Science.gov (United States)

Zhang, Yang; Zhang, Xin; Wang, Litao; Zhang, Qiang; Duan, Fengkui; He, Kebin

2016-01-01

In this work, the application of the online-coupled Weather Research and Forecasting model with chemistry (WRF/Chem) version 3.3.1 is evaluated over East Asia for January, April, July, and October 2005 and compared with results from a previous application of an offline model system, i.e., the Mesoscale Model and Community Multiple Air Quality modeling system (MM5/CMAQ). The evaluation of WRF/Chem is performed using multiple observational datasets from satellites and surface networks in mainland China, Hong Kong, Taiwan, and Japan. WRF/Chem simulates well specific humidity (Q2) and downward longwave and shortwave radiation (GLW and GSW) with normalized mean biases (NMBs) within 24%, but shows moderate to large biases for temperature at 2-m (T2) (NMBs of -9.8% to 75.6%) and precipitation (NMBs of 11.4-92.7%) for some months, and wind speed at 10-m (WS10) (NMBs of 66.5-101%), for all months, indicating some limitations in the YSU planetary boundary layer scheme, the Purdue Lin cloud microphysics, and the Grell-Devenyi ensemble scheme. WRF/Chem can simulate the column abundances of gases reasonably well with NMBs within 30% for most months but moderately to significantly underpredicts the surface concentrations of major species at all sites in nearly all months with NMBs of -72% to -53.8% for CO, -99.4% to -61.7% for NOx, -84.2% to -44.5% for SO2, -63.9% to -25.2% for PM2.5, and -68.9% to 33.3% for PM10, and aerosol optical depth in all months except for October with NMBs of -38.7% to -16.2%. The model significantly overpredicts surface concentrations of O3 at most sites in nearly all months with NMBs of up to 160.3% and NO3- at the Tsinghua site in all months. Possible reasons for large underpredictions include underestimations in the anthropogenic emissions of CO, SO2, and primary aerosol, inappropriate vertical distributions of emissions of SO2 and NO2, uncertainties in upper boundary conditions (e.g., for O3 and CO), missing or inaccurate model representations (e

Diversity of Rock Compositions at Gale Crater Observed by ChemCam and APXS on Curiosity, and Comparison to Meteorite and Orbital Observations

Science.gov (United States)

Wiens, R. C.; Maurice, S.; Grotzinger, J. P.; Gellert, R.; Mangold, N.; Sautter, V.; Ollila, A.; Dyar, M. D.; Le Mouelic, S.; Ehlmann, B. L.; Clegg, S. M.; Lanza, N.; Cousin, A.; Forni, O.; Gasnault, O.; Lasue, J.; Blaney, D. L.; Newsom, H. E.; Herkenhoff, K. E.; Anderson, R. B.; D'Uston, L.; Bridges, N. T.; Fabre, C.; Meslin, P.; Johnson, J.; Vaniman, D.; Bridges, J.; Dromart, G.; Schmidt, M. E.; Team, M.

2013-12-01

Gale crater was selected as the Curiosity landing site because of the apparent sedimentary spectral signatures seen from orbit. Sedimentary materials on Mars have to this point showed very little expression of major element mobility, so compositions of precursor igneous minerals play a strong role in the compositions of sediments. In addition, pebbles and float rocks on Bradbury Rise (sols 0-50, > 324) appear to be mostly igneous in origin, and are assumed to have been carried down from the crater rim. Overall in the first year on Mars ChemCam obtained >75,000 LIBS spectra on > 2,000 observation points, supported by > 1,000 RMI images, and APXS obtained a significant number of observations. These show surprisingly variable compositions. The mean ChemCam compositions for Bradbury Rise dust-free rocks and pebbles (62 locations) give SiO2 = 56%, FeOT = 16% and show high alkalis consistent with Jake Matijevic (sol ~47) APXS Na2O ~6.6 wt%. ChemCam observations on the conglomerate Link (sol 27) gave Rb > 150 ppm and Sr > 1500 ppm. These compositions imply the presence of abundant alkali feldspars in the material infilling the lower parts of Gale crater. They are generally consistent with the more feldspar-rich SNC meteorites but show a radical departure from larger scale orbital observations, e.g., GRS, raising the question of how widespread these compositions are outside of Gale crater. Sedimentary materials at Yellowknife Bay encompassing the Sheepbed (sols 125-300) and Shaler (sols 121, 311-324) units, potentially including Point Lake (sols 301-310) and Rocknest (sols 57-97), appear to have incorporated varying amounts of igneous source materials. Seven rocks investigated at Rocknest show significant additions of Fe, with mean FeOT = 25% (154 locations), suggesting that FeO was a cementing agent. ChemCam observations at Shaler show varying amounts of alkali feldspar (i.e., related to Bradbury Rise), Fe-rich material (Rocknest-like), and potassium-rich material

FastChem: A computer program for efficient complex chemical equilibrium calculations in the neutral/ionized gas phase with applications to stellar and planetary atmospheres

Science.gov (United States)

Stock, Joachim W.; Kitzmann, Daniel; Patzer, A. Beate C.; Sedlmayr, Erwin

2018-06-01

For the calculation of complex neutral/ionized gas phase chemical equilibria, we present a semi-analytical versatile and efficient computer program, called FastChem. The applied method is based on the solution of a system of coupled nonlinear (and linear) algebraic equations, namely the law of mass action and the element conservation equations including charge balance, in many variables. Specifically, the system of equations is decomposed into a set of coupled nonlinear equations in one variable each, which are solved analytically whenever feasible to reduce computation time. Notably, the electron density is determined by using the method of Nelder and Mead at low temperatures. The program is written in object-oriented C++ which makes it easy to couple the code with other programs, although a stand-alone version is provided. FastChem can be used in parallel or sequentially and is available under the GNU General Public License version 3 at https://github.com/exoclime/FastChem together with several sample applications. The code has been successfully validated against previous studies and its convergence behavior has been tested even for extreme physical parameter ranges down to 100 K and up to 1000 bar. FastChem converges stable and robust in even most demanding chemical situations, which posed sometimes extreme challenges for previous algorithms.

Total mercury and methylmercury concentrations over a gradient of contamination in earthworms living in rice paddy soil.

Science.gov (United States)

Abeysinghe, Kasun S; Yang, Xiao-Dong; Goodale, Eben; Anderson, Christopher W N; Bishop, Kevin; Cao, Axiang; Feng, Xinbin; Liu, Shengjie; Mammides, Christos; Meng, Bo; Quan, Rui-Chang; Sun, Jing; Qiu, Guangle

2017-05-01

Mercury (Hg) deposited from emissions or from local contamination, can have serious health effects on humans and wildlife. Traditionally, Hg has been seen as a threat to aquatic wildlife, because of its conversion in suboxic conditions into bioavailable methylmercury (MeHg), but it can also threaten contaminated terrestrial ecosystems. In Asia, rice paddies in particular may be sensitive ecosystems. Earthworms are soil-dwelling organisms that have been used as indicators of Hg bioavailability; however, the MeHg concentrations they accumulate in rice paddy environments are not well known. Earthworm and soil samples were collected from rice paddies at progressive distances from abandoned mercury mines in Guizhou, China, and at control sites without a history of Hg mining. Total Hg (THg) and MeHg concentrations declined in soil and earthworms as distance increased from the mines, but the percentage of THg that was MeHg, and the bioaccumulation factors in earthworms, increased over this gradient. This escalation in methylation and the incursion of MeHg into earthworms may be influenced by more acidic soil conditions and higher organic content further from the mines. In areas where the source of Hg is deposition, especially in water-logged and acidic rice paddy soil, earthworms may biomagnify MeHg more than was previously reported. It is emphasized that rice paddy environments affected by acidifying deposition may be widely dispersed throughout Asia. Environ Toxicol Chem 2017;36:1202-1210. © 2016 SETAC. © 2016 SETAC.

Inclusion of biomass burning in WRF-Chem: impact of wildfires on weather forecasts

Directory of Open Access Journals (Sweden)

G. Grell

2011-06-01

Full Text Available A plume rise algorithm for wildfires was included in WRF-Chem, and applied to look at the impact of intense wildfires during the 2004 Alaska wildfire season on weather simulations using model resolutions of 10 km and 2 km. Biomass burning emissions were estimated using a biomass burning emissions model. In addition, a 1-D, time-dependent cloud model was used online in WRF-Chem to estimate injection heights as well as the vertical distribution of the emission rates. It was shown that with the inclusion of the intense wildfires of the 2004 fire season in the model simulations, the interaction of the aerosols with the atmospheric radiation led to significant modifications of vertical profiles of temperature and moisture in cloud-free areas. On the other hand, when clouds were present, the high concentrations of fine aerosol (PM_2.5 and the resulting large numbers of Cloud Condensation Nuclei (CCN had a strong impact on clouds and cloud microphysics, with decreased precipitation coverage and precipitation amounts during the first 12 h of the integration. During the afternoon, storms were of convective nature and appeared significantly stronger, probably as a result of both the interaction of aerosols with radiation (through an increase in CAPE as well as the interaction with cloud microphysics.

Source apportionment of atmospheric mercury pollution in China using the GEOS-Chem model

International Nuclear Information System (INIS)

Wang, Long; Wang, Shuxiao; Zhang, Lei; Wang, Yuxuan; Zhang, Yanxu; Nielsen, Chris; McElroy, Michael B.; Hao, Jiming

2014-01-01

China is the largest atmospheric mercury (Hg) emitter in the world. Its Hg emissions and environmental impacts need to be evaluated. In this study, China's Hg emission inventory is updated to 2007 and applied in the GEOS-Chem model to simulate the Hg concentrations and depositions in China. Results indicate that simulations agree well with observed background Hg concentrations. The anthropogenic sources contributed 35–50% of THg concentration and 50–70% of total deposition in polluted regions. Sensitivity analysis was performed to assess the impacts of mercury emissions from power plants, non-ferrous metal smelters and cement plants. It is found that power plants are the most important emission sources in the North China, the Yangtze River Delta (YRD) and the Pearl River Delta (PRD) while the contribution of non-ferrous metal smelters is most significant in the Southwest China. The impacts of cement plants are significant in the YRD, PRD and Central China. - Highlights: • China's anthropogenic mercury emission was 643.1 t in 2007. • GEOS-Chem model well reproduces the background Hg concentrations. • Anthropogenic emissions contribute 35–50% of Hg concentrations in polluted regions. • The priorities for mercury control in polluted regions are identified. - Anthropogenic Hg emissions are updated and their impacts on atmospheric mercury concentrations and depositions are quantified for China

ChemSession'11 - 8. Warsaw Seminar of the PhD Students in Chemistry - Abstracts

International Nuclear Information System (INIS)

Madura, I.

2011-01-01

Book of Abstracts contains short descriptions of presentations: 4 lectures, 1 communication and 149 posters presented during ChemSession'11 - 8 th Warsaw Seminar of the PhD Students in Chemistry (Warsaw, 13.05.2011). Several posters were devoted to the radiochemistry, radiochemical analysis, radiation chemistry, application of the radionuclides and radiobiology. Some posters on the material science dealing with materials important to nuclear sciences can be also mentioned.

Diffusive flux of PAHs across sediment-water and water-air interfaces at urban superfund sites.

Science.gov (United States)

Minick, D James; Anderson, Kim A

2017-09-01

Superfund sites may be a source of polycyclic aromatic hydrocarbons (PAHs) to the surrounding environment. These sites can also act as PAH sinks from present-day anthropogenic activities, especially in urban locations. Understanding PAH transport across environmental compartments helps to define the relative contributions of these sources and is therefore important for informing remedial and management decisions. In the present study, paired passive samplers were co-deployed at sediment-water and water-air interfaces within the Portland Harbor Superfund Site and the McCormick and Baxter Superfund Site. These sites, located along the Willamette River (Portland, OR, USA), have PAH contamination from both legacy and modern sources. Diffusive flux calculations indicate that the Willamette River acts predominantly as a sink for low molecular weight PAHs from both the sediment and the air. The sediment was also predominantly a source of 4- and 5-ring PAHs to the river, and the river was a source of these same PAHs to the air, indicating that legacy pollution may be contributing to PAH exposure for residents of the Portland urban center. At the remediated McCormick and Baxter Superfund Site, flux measurements highlight locations within the sand and rock sediment cap where contaminant breakthrough is occurring. Environ Toxicol Chem 2017;36:2281-2289. © 2017 SETAC. © 2017 SETAC.

Interactions of metal-based engineered nanoparticles with aquatic higher plants: A review of the state of current knowledge.

Science.gov (United States)

Thwala, Melusi; Klaine, Stephen J; Musee, Ndeke

2016-07-01

The rising potential for the release of engineered nanoparticles (ENPs) into aquatic environments requires evaluation of risks to protect ecological health. The present review examines knowledge pertaining to the interactions of metal-based ENPs with aquatic higher plants, identifies information gaps, and raises considerations for future research to advance knowledge on the subject. The discussion focuses on ENPs' bioaccessibility; uptake, adsorption, translocation, and bioaccumulation; and toxicity effects on aquatic higher plants. An information deficit surrounds the uptake of ENPs and associated dynamics, because the influence of ENP characteristics and water quality conditions has not been well documented. Dissolution appears to be a key mechanism driving bioaccumulation of ENPs, whereas nanoparticulates often adsorb to plant surfaces with minimal internalization. However, few reports document the internalization of ENPs by plants; thus, the role of nanoparticulates' internalization in bioaccumulation and toxicity remains unclear, requiring further investigation. The toxicities of metal-based ENPs mainly have been associated with dissolution as a predominant mechanism, although nano toxicity has also been reported. To advance knowledge in this domain, future investigations need to integrate the influence of ENP characteristics and water physicochemical parameters, as their interplay determines ENP bioaccessibility and influences their risk to health of aquatic higher plants. Furthermore, harmonization of test protocols is recommended for fast tracking the generation of comparable data. Environ Toxicol Chem 2016;35:1677-1694. © 2016 SETAC. © 2016 SETAC.

A standardized tritrophic small-scale system (TriCosm) for the assessment of stressor-induced effects on aquatic community dynamics.

Science.gov (United States)

Riedl, Verena; Agatz, Annika; Benstead, Rachel; Ashauer, Roman

2018-04-01

Chemical impacts on the environment are routinely assessed in single-species tests. They are employed to measure direct effects on nontarget organisms, but indirect effects on ecological interactions can only be detected in multispecies tests. Micro- and mesocosms are more complex and environmentally realistic, yet they are less frequently used for environmental risk assessment because resource demand is high, whereas repeatability and statistical power are often low. Test systems fulfilling regulatory needs (i.e., standardization, repeatability, and replication) and the assessment of impacts on species interactions and indirect effects are lacking. In the present study we describe the development of the TriCosm, a repeatable aquatic multispecies test with 3 trophic levels and increased statistical power. High repeatability of community dynamics of 3 interacting aquatic populations (algae, Ceriodaphnia, and Hydra) was found with an average coefficient of variation of 19.5% and the ability to determine small effect sizes. The TriCosm combines benefits of both single-species tests (fulfillment of regulatory requirements) and complex multispecies tests (ecological relevance) and can be used, for instance, at an intermediate tier in environmental risk assessment. Furthermore, comparatively quickly generated population and community toxicity data can be useful for the development and testing of mechanistic effect models. Environ Toxicol Chem 2018;37:1051-1060. © 2017 SETAC. © 2017 SETAC.

Not all that glitters is gold-Electron microscopy study on uptake of gold nanoparticles in Daphnia magna and related artifacts.

Science.gov (United States)

Jensen, Louise Helene Søgaard; Skjolding, Lars Michael; Thit, Amalie; Sørensen, Sara Nørgaard; Købler, Carsten; Mølhave, Kristian; Baun, Anders

2017-06-01

Increasing use of engineered nanoparticles has led to extensive research into their potential hazards to the environment and human health. Cellular uptake from the gut is sparsely investigated, and microscopy techniques applied for uptake studies can result in misinterpretations. Various microscopy techniques were used to investigate internalization of 10-nm gold nanoparticles in Daphnia magna gut lumen and gut epithelial cells following 24-h exposure and outline potential artifacts (i.e., high-contrast precipitates from sample preparation related to these techniques). Light sheet microscopy confirmed accumulation of gold nanoparticles in the gut lumen. Scanning transmission electron microscopy and elemental analysis revealed gold nanoparticles attached to the microvilli of gut cells. Interestingly, the peritrophic membrane appeared to act as a semipermeable barrier between the lumen and the gut epithelium, permitting only single particles through. Structures resembling nanoparticles were also observed inside gut cells. Elemental analysis could not verify these to be gold, and they were likely artifacts from the preparation, such as osmium and iron. Importantly, gold nanoparticles were found inside holocrine cells with disrupted membranes. Thus, false-positive observations of nanoparticle internalization may result from either preparation artifacts or mistaking disrupted cells for intact cells. These findings emphasize the importance of cell integrity and combining elemental analysis with the localization of internalized nanoparticles using transmission electron microscopy. Environ Toxicol Chem 2017;36:1503-1509. © 2016 SETAC. © 2016 SETAC.

Operational on-line coupled chemical weather forecasts for Europe with WRF/Chem

Science.gov (United States)

Hirtl, Marcus; Mantovani, Simone; Krüger, Bernd C.; Flandorfer, Claudia; Langer, Matthias

2014-05-01

Air quality is a key element for the well-being and quality of life of European citizens. Air pollution measurements and modeling tools are essential for the assessment of air quality according to EU legislation. The responsibilities of ZAMG as the national weather service of Austria include the support of the federal states and the public in questions connected to the protection of the environment in the frame of advisory and counseling services as well as expert opinions. ZAMG conducts daily Air-Quality forecasts using the on-line coupled model WRF/Chem. Meteorology is simulated simultaneously with the emissions, turbulent mixing, transport, transformation, and fate of trace gases and aerosols. The emphasis of the application is on predicting pollutants over Austria. Two domains are used for the simulations: the mother domain covers Europe with a resolution of 12 km, the inner domain includes the alpine region with a horizontal resolution of 4 km; 45 model levels are used in the vertical direction. The model runs 2 times per day for a period of 72 hours and is initialized with ECMWF forecasts. On-line coupled models allow considering two-way interactions between different atmospheric processes including chemistry (both gases and aerosols), clouds, radiation, boundary layer, emissions, meteorology and climate. In the operational set-up direct-, indirect and semi-direct effects between meteorology and air chemistry are enabled. The model is running on the HPCF (High Performance Computing Facility) of the ZAMG. In the current set-up 1248 CPUs are used. As the simulations need a big amount of computing resources, a method to safe I/O-time was implemented. Every MPI task writes all its output into the shared memory filesystem of the compute nodes. Once the WRF/Chem integration is finished, all split NetCDF-files are merged and saved on the global file system. The merge-routine is based on parallel-NetCDF. With this method the model runs about 30% faster on the SGI

Avaliação in vivo do efeito hipocolesterolêmico e toxicológico preliminar do extrato bruto hidroalcoólico e decocção da Vitex megapotamica (Spreng Moldenke (V. montevidensis Cham.

Directory of Open Access Journals (Sweden)

Anna Paula Brandt

Full Text Available As doenças cardiovasculares (DC estão, de modo geral, associadas a elevados níveis séricos de lipídeos, atingindo homens e mulheres, sem distinção de idade. Entre as propriedades atribuídas pela medicina popular à Vitex megapotamica (Spreng Moldenke (V. montevidensis Cham -Tarumã estão a de reduzir os níveis séricos de colesterol e triglicerídeo. O principal objetivo do presente estudo foi avaliar o potencial hipocolesterolêmico e hipolipidêmico da V. megapotamica, bem como fazer um estudo toxicológico preliminar. Para tanto, foi realizada indução hiperlipidêmica usando um modelo que preconiza o emprego de propiltiuracil 1,25 mg/300 g de peso e colesterol 200 mg/kg de peso, aplicados via oral em ratos machos pesando 300 ± 10 g. Foi administrado, por via oral, aos animais hiperlipidêmicos previamente induzidos 300 mg/kg de extrato hidroalcoólico das folhas de V. megapotamica ou 300 mL da decocção da casca da planta. Após o final de cada tratamento, o perfil lipídico foi ensaiado, bem como os níveis de glicose, quando relevante. Nossos resultados confirmaram o efeito hipolipidêmico do extrato hidroalcoólico e da decocção pela redução dos níveis séricos de colesterol e triacilglicerol nas concentrações, via e forma utilizadas. Além disso, foi possível verificar que não houve lesão cardíaca, hepática ou renal pelo extrato e decocção utilizados nas avaliações toxicológicas preliminares ensaiadas.

WRF and WRF-Chem v3.5.1 simulations of meteorology and black carbon concentrations in the Kathmandu Valley

Directory of Open Access Journals (Sweden)

A. Mues

2018-06-01

Full Text Available An evaluation of the meteorology simulated using the Weather Research and Forecast (WRF model for the region of south Asia and Nepal with a focus on the Kathmandu Valley is presented. A particular focus of the model evaluation is placed on meteorological parameters that are highly relevant to air quality such as wind speed and direction, boundary layer height and precipitation. The same model setup is then used for simulations with WRF including chemistry and aerosols (WRF-Chem. A WRF-Chem simulation has been performed using the state-of-the-art emission database, EDGAR HTAP v2.2, which is the Emission Database for Global Atmospheric Research of the Joint Research Centre (JRC of the European Commission, in cooperation with the Task Force on Hemispheric Transport of Air Pollution (TF HTAP organized by the United Nations Economic Commission for Europe, along with a sensitivity simulation using observation-based black carbon emission fluxes for the Kathmandu Valley. The WRF-Chem simulations are analyzed in comparison to black carbon measurements in the valley and to each other.The evaluation of the WRF simulation with a horizontal resolution of 3×3 km2 shows that the model is often able to capture important meteorological parameters inside the Kathmandu Valley and the results for most meteorological parameters are well within the range of biases found in other WRF studies especially in mountain areas. But the evaluation results also clearly highlight the difficulties of capturing meteorological parameters in such complex terrain and reproducing subgrid-scale processes with a horizontal resolution of 3×3 km2. The measured black carbon concentrations are typically systematically and strongly underestimated by WRF-Chem. A sensitivity study with improved emissions in the Kathmandu Valley shows significantly reduced biases but also underlines several limitations of such corrections. Further improvements of the model and of the emission data are

The ChemChar process for hazardous-waste treatment

International Nuclear Information System (INIS)

McGowin, A.E.

1991-01-01

The ChemChar Reverse-Burn Gasification Process has been studied for application to the thermal destruction of radioactive waste organic ion exchange resins. The resulting char was mixed with cement to form a dry, leach-resistant final disposal product. Successful regeneration of spent granular activated carbons was achieved with reverse-burn gasification. Regeneration parameters such as moisture content and supplemental fuel addition were investigated. The performance of regenerated carbon was evaluated by batch equilibrium and breakthrough assay and was comparable to that of the original. Surface areas were determined by the BET method. The fate of mercury during reverse-burn gasification was investigated. TRB Char adsorbent was used to remove mercury vapor emission from the process. The use of petroleum coke as a substrate for gasification of wastes was studied. Petroleum coke was activated by reverse-burn gasification to produce a highly porous, low surface area solid. Destruction efficiency for hexachlorobenzene on activated coke was considerably lower than on coal char, however, the addition of iron appeared to catalyze hexachlorobenzene gasification

Estudio toxicológico de un producto derivado de la caña de azúcar

Directory of Open Access Journals (Sweden)

Carmen Luisa García Rivero

1997-08-01

Full Text Available Se presentan los resultados obtenidos en la evaluación toxicológica preclínica de un principio activo formulado en crema con propiedades cicatrizantes y antifúngicas a partir de un producto natural derivado de la caña de azúcar, al cual se le determinó su inocuidad en animales de experimentación mediante la estimación de la dosis letal media en conejos F1 y ratas albinas Wistar, utilizando niveles de dosis elevados. También se estudió el potencial irritante sobre la piel, mucosa ocular, vaginal y rectal, así como su potencial como agente sensibilizante. De forma general los síntomas tóxicos observados no fueron significativos y desaparecieron en un período corto, no se presentó mortalidad y se comprobó la ausencia de efectos irritantes sobre la piel y mucosas evaluadas. Se demostró que el producto no es un agente sensibilizante. Los resultados obtenidos en el estudio realizado permiten clasificar al producto de una baja toxicidad.This paper reports on the results obtained from the preclinical toxicity assessment of an active ingredient formulated as a cream having healing and antifungal properties which was obtained from a natural product derived from sugar cane. The drug testing included the determination of its safety in experimental animals by the estimation of the mean lethal dose in rabbits F1 and albino Wistar rats using high dose levels. The potential irritancy on the skin, ophthalmic, vaginal and rectal mucosa was also studied, as well as the potential as a sensibilizing agent. Overall, the toxic symptoms observed were found to be no significant and they dissapeared within a short period of time. There was no mortality and the absence of irritant effects on the skin and mucosa was evidenced in the evaluation. It was proved that this product is not a sensibilizing agent. Results obtained from the study carried out allow to classify this product as having low toxicity levels.

In situ detection of boron by ChemCam on Mars

Science.gov (United States)

Gasda, Patrick J.; Haldeman, Ethan B.; Wiens, Roger C.; Rapin, William; Bristow, Thomas F.; Bridges, John C.; Schwenzer, Susanne P.; Clark, Benton; Herkenhoff, Kenneth; Frydenvang, Jens; Lanza, Nina L.; Maurice, Sylvestre; Clegg, Samuel; Delapp, Dorothea M.; Sanford, Veronica L.; Bodine, Madeleine R.; McInroy, Rhonda

2017-09-01

We report the first in situ detection of boron on Mars. Boron has been detected in Gale crater at levels Curiosity rover ChemCam instrument in calcium-sulfate-filled fractures, which formed in a late-stage groundwater circulating mainly in phyllosilicate-rich bedrock interpreted as lacustrine in origin. We consider two main groundwater-driven hypotheses to explain the presence of boron in the veins: leaching of borates out of bedrock or the redistribution of borate by dissolution of borate-bearing evaporite deposits. Our results suggest that an evaporation mechanism is most likely, implying that Gale groundwaters were mildly alkaline. On Earth, boron may be a necessary component for the origin of life; on Mars, its presence suggests that subsurface groundwater conditions could have supported prebiotic chemical reactions if organics were also present and provides additional support for the past habitability of Gale crater.

Comment on ``On the Crooks fluctuation theorem and the Jarzynski equality'' [J. Chem. Phys. 129, 091101 (2008)

Science.gov (United States)

Adib, Artur B.

2009-06-01

It has recently been argued that a self-consistency condition involving the Jarzynski equality (JE) and the Crooks fluctuation theorem (CFT) is violated for a simple Brownian process [L. Y. Chen, J. Chem. Phys.129, 091101 (2008)]. This note adopts the definitions in the original formulation of the JE and CFT and demonstrates the contrary.

Exploring Natural Products from the Biodiversity of Pakistan for Computational Drug Discovery Studies: Collection, Optimization, Design and Development of A Chemical Database (ChemDP).

Science.gov (United States)

Mirza, Shaher Bano; Bokhari, Habib; Fatmi, Muhammad Qaiser

2015-01-01

Pakistan possesses a rich and vast source of natural products (NPs). Some of these secondary metabolites have been identified as potent therapeutic agents. However, the medicinal usage of most of these compounds has not yet been fully explored. The discoveries for new scaffolds of NPs as inhibitors of certain enzymes or receptors using advanced computational drug discovery approaches are also limited due to the unavailability of accurate 3D structures of NPs. An organized database incorporating all relevant information, therefore, can facilitate to explore the medicinal importance of the metabolites from Pakistani Biodiversity. The Chemical Database of Pakistan (ChemDP; release 01) is a fully-referenced, evolving, web-based, virtual database which has been designed and developed to introduce natural products (NPs) and their derivatives from the biodiversity of Pakistan to Global scientific communities. The prime aim is to provide quality structures of compounds with relevant information for computer-aided drug discovery studies. For this purpose, over 1000 NPs have been identified from more than 400 published articles, for which 2D and 3D molecular structures have been generated with a special focus on their stereochemistry, where applicable. The PM7 semiempirical quantum chemistry method has been used to energy optimize the 3D structure of NPs. The 2D and 3D structures can be downloaded as .sdf, .mol, .sybyl, .mol2, and .pdb files - readable formats by many chemoinformatics/bioinformatics software packages. Each entry in ChemDP contains over 100 data fields representing various molecular, biological, physico-chemical and pharmacological properties, which have been properly documented in the database for end users. These pieces of information have been either manually extracted from the literatures or computationally calculated using various computational tools. Cross referencing to a major data repository i.e. ChemSpider has been made available for overlapping

An investigation of methods for injecting emissions from boreal wildfires using WRF-Chem during ARCTAS

OpenAIRE

W. R. Sessions; H. E. Fuelberg; R. A. Kahn; D. M. Winker

2010-01-01

The Weather Research and Forecasting Model (WRF) is considered a "next generation" mesoscale meteorology model. The inclusion of a chemistry module (WRF-Chem) allows transport simulations of chemical and aerosol species such as those observed during NASA's Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) in 2008. The ARCTAS summer deployment phase during June and July coincided with large boreal wildfires in Saskatchewan and Eastern Russia.

ChemEngine: harvesting 3D chemical structures of supplementary data from PDF files.

Science.gov (United States)

Karthikeyan, Muthukumarasamy; Vyas, Renu

2016-01-01

Digital access to chemical journals resulted in a vast array of molecular information that is now available in the supplementary material files in PDF format. However, extracting this molecular information, generally from a PDF document format is a daunting task. Here we present an approach to harvest 3D molecular data from the supporting information of scientific research articles that are normally available from publisher's resources. In order to demonstrate the feasibility of extracting truly computable molecules from PDF file formats in a fast and efficient manner, we have developed a Java based application, namely ChemEngine. This program recognizes textual patterns from the supplementary data and generates standard molecular structure data (bond matrix, atomic coordinates) that can be subjected to a multitude of computational processes automatically. The methodology has been demonstrated via several case studies on different formats of coordinates data stored in supplementary information files, wherein ChemEngine selectively harvested the atomic coordinates and interpreted them as molecules with high accuracy. The reusability of extracted molecular coordinate data was demonstrated by computing Single Point Energies that were in close agreement with the original computed data provided with the articles. It is envisaged that the methodology will enable large scale conversion of molecular information from supplementary files available in the PDF format into a collection of ready- to- compute molecular data to create an automated workflow for advanced computational processes. Software along with source codes and instructions available at https://sourceforge.net/projects/chemengine/files/?source=navbar.Graphical abstract.

Lightning NOx emissions over the USA constrained by TES ozone observations and the GEOS-Chem model

Science.gov (United States)

Jourdain, L.; Kulawik, S. S.; Worden, H. M.; Pickering, K. E.; Worden, J.; Thompson, A. M.

2010-01-01

Improved estimates of NOx from lightning sources are required to understand tropospheric NOx and ozone distributions, the oxidising capacity of the troposphere and corresponding feedbacks between chemistry and climate change. In this paper, we report new satellite ozone observations from the Tropospheric Emission Spectrometer (TES) instrument that can be used to test and constrain the parameterization of the lightning source of NOx in global models. Using the National Lightning Detection (NLDN) and the Long Range Lightning Detection Network (LRLDN) data as well as the HYPSLIT transport and dispersion model, we show that TES provides direct observations of ozone enhanced layers downwind of convective events over the USA in July 2006. We find that the GEOS-Chem global chemistry-transport model with a parameterization based on cloud top height, scaled regionally and monthly to OTD/LIS (Optical Transient Detector/Lightning Imaging Sensor) climatology, captures the ozone enhancements seen by TES. We show that the model's ability to reproduce the location of the enhancements is due to the fact that this model reproduces the pattern of the convective events occurrence on a daily basis during the summer of 2006 over the USA, even though it does not well represent the relative distribution of lightning intensities. However, this model with a value of 6 Tg N/yr for the lightning source (i.e.: with a mean production of 260 moles NO/Flash over the USA in summer) underestimates the intensities of the ozone enhancements seen by TES. By imposing a production of 520 moles NO/Flash for lightning occurring in midlatitudes, which better agrees with the values proposed by the most recent studies, we decrease the bias between TES and GEOS-Chem ozone over the USA in July 2006 by 40%. However, our conclusion on the strength of the lightning source of NOx is limited by the fact that the contribution from the stratosphere is underestimated in the GEOS-Chem simulations.

ChemCam activities and discoveries during the nominal mission of the Mars Science Laboratory in Gale crater, Mars

Science.gov (United States)

Maurice, Sylvestre; Clegg, Samuel M.; Wiens, Roger C.; Gasnault, O.; Rapin, W.; Forni, O.; Cousin, Agnes; Sautter, V.; Mangold, Nicolas; Le Deit, L.; Nachon, Marion; Anderson, Ryan; Lanza, Nina; Fabre, Cecile; Payre, Valerie; Lasue, Jeremie; Meslin, Pierre-Yves; LeVeille, Richard A.; Barraclough, Bruce; Beck, Pierre; Bender, Steven C.; Berger, Gilles; Bridges, John C.; Bridges, Nathan; Dromert, Gilles; Dyar, M. Darby; Francis, Raymond; Frydenvang, Jens; Gondet, B.; Ehlmann, Bethany L.; Herkenhoff, Kenneth E.; Johnson, Jeffrey R.; Langevin, Yves; Madsen Morten B.,; Melikechi, N.; Lacour, J.-L.; Le Mouelic, Stephane; Lewin, Eric; Newsom, Horton E.; Ollila, Ann M.; Pinet, Patrick; Schroder, S.; Sirven, Jean-Baptiste; Tokar, Robert L.; Toplis, M.J.; d'Uston, Claude; Vaniman, David; Vasavada, Ashwin R.

2016-01-01

At Gale crater, Mars, ChemCam acquired its first laser-induced breakdown spectroscopy (LIBS) target on Sol 13 of the landed portion of the mission (a Sol is a Mars day). Up to Sol 800, more than 188000 LIBS spectra were acquired on more than 5800 points distributed over about 650 individual targets. We present a comprehensive review of ChemCam scientific accomplishments during that period, together with a focus on the lessons learned from the first use of LIBS in space. For data processing, we describe new tools that had to be developed to account for the uniqueness of Mars data. With regard to chemistry, we present a summary of the composition range measured on Mars for major-element oxides (SiO2, TiO2, Al2O3, FeOT, MgO, CaO, Na2O, K2O) based on various multivariate models, with associated precisions. ChemCam also observed H, and the non-metallic elements C, O, P, and S, which are usually difficult to quantify with LIBS. F and Cl are observed through their molecular lines. We discuss the most relevant LIBS lines for detection of minor and trace elements (Li, Rb, Sr, Ba, Cr, Mn, Ni, and Zn). These results were obtained thanks to comprehensive ground reference datasets, which are set to mimic the expected mineralogy and chemistry on Mars. With regard to the first use of LIBS in space, we analyze and quantify, often for the first time, each of the advantages of using stand-off LIBS in space: no sample preparation, analysis within its petrological context, dust removal, sub-millimeter scale investigation, multi-point analysis, the ability to carry out statistical surveys and whole-rock analyses, and rapid data acquisition. We conclude with a discussion of ChemCam performance to survey the geochemistry of Mars, and its valuable support of decisions about selecting where and whether to make observations with more time and resource-intensive tools in the rover's instrument suite. In the end, we present a bird's-eye view of the many scientific results: discovery of felsic

Bioaccumulation, stress, and swimming impairment in Daphnia magna exposed to multiwalled carbon nanotubes, graphene, and graphene oxide.

Science.gov (United States)

Cano, Amanda M; Maul, Jonathan D; Saed, Mohammad; Shah, Smit A; Green, Micah J; Cañas-Carrell, Jaclyn E

2017-08-01

The use of carbon-based nanomaterials (CNMs) such as multiwalled carbon nanotubes (MWCNTs), graphene, and graphene oxide (GO) is increasing across many applications because of their unique and versatile properties. These CNMs may enter the aquatic environment through many pathways, creating the potential for organism exposure. The present study addresses the bioaccumulation and toxicity seen in Daphnia magna exposed to CNMs dispersed in sodium dodecyl benzene sulfonate (SDBS). In study I, D. magna were exposed to varying outer diameters of MWCNTs for 24 h in moderately hard or hard freshwater. Bioaccumulation of MWCNT was found in all treatments, with the highest concentrations (0.53 ± 0.27 μg/g) in D. magna exposed in hard freshwater (p < 0.005). The median lethal concentration (LC50) was determined for D. magna exposed to CNMs in moderately hard and hard freshwater. In study II, D. magna were exposed to CNMs for 72 h in moderately hard freshwater to assess swimming velocity and generation of reactive oxygen species (ROS) detected by dichlorofluorescein fluorescence. An overall decrease was seen in D. magna swimming velocity after exposure to CNMs. The generation of ROS was significantly higher (1.54 ± 0.38 dichlorofluorescein mM/mg dry wt) in D. magna exposed to MWCNTs of smaller outer diameters than in controls after 72 h (p < 0.05). These results suggest that further investigation of CNM toxicity and behavior in the aquatic environment is needed. Environ Toxicol Chem 2017;36:2199-2204. © 2017 SETAC. © 2017 SETAC.

The potassic sedimentary rocks in Gale Crater, Mars, as seen by ChemCam Onboard Curiosity

Science.gov (United States)

Le Deit, Laetitia; Mangold, Nicolas; Forni, Olivier; Cousin, Agnes; Lasue, Jeremie; Schröder, Susanne; Wiens, Roger C.; Sumner, Dawn Y.; Fabre, Cecile; Stack, Katherine M.; Anderson, Ryan; Blaney, Diana L.; Clegg, Samuel M.; Dromart, Gilles; Fisk, Martin; Gasnault, Olivier; Grotzinger, John P.; Gupta, Sanjeev; Lanza, Nina; Le Mouélic, Stephane; Maurice, Sylvestre; McLennan, Scott M.; Meslin, Pierre-Yves; Nachon, Marion; Newsom, Horton E.; Payre, Valerie; Rapin, William; Rice, Melissa; Sautter, Violaine; Treiman, Alan H.

2016-01-01

The Mars Science Laboratory rover Curiosity encountered potassium-rich clastic sedimentary rocks at two sites in Gale Crater, the waypoints Cooperstown and Kimberley. These rocks include several distinct meters thick sedimentary outcrops ranging from fine sandstone to conglomerate, interpreted to record an ancient fluvial or fluvio-deltaic depositional system. From ChemCam Laser-Induced Breakdown Spectroscopy (LIBS) chemical analyses, this suite of sedimentary rocks has an overall mean K2O abundance that is more than 5 times higher than that of the average Martian crust. The combined analysis of ChemCam data with stratigraphic and geographic locations reveals that the mean K2O abundance increases upward through the stratigraphic section. Chemical analyses across each unit can be represented as mixtures of several distinct chemical components, i.e., mineral phases, including K-bearing minerals, mafic silicates, Fe-oxides, and Fe-hydroxide/oxyhydroxides. Possible K-bearing minerals include alkali feldspar (including anorthoclase and sanidine) and K-bearing phyllosilicate such as illite. Mixtures of different source rocks, including a potassium-rich rock located on the rim and walls of Gale Crater, are the likely origin of observed chemical variations within each unit. Physical sorting may have also played a role in the enrichment in K in the Kimberley formation. The occurrence of these potassic sedimentary rocks provides additional evidence for the chemical diversity of the crust exposed at Gale Crater.

Fourier-transform infrared spectroscopy as a novel approach to providing effect-based endpoints in duckweed toxicity testing.

Science.gov (United States)

Hu, Li-Xin; Ying, Guang-Guo; Chen, Xiao-Wen; Huang, Guo-Yong; Liu, You-Sheng; Jiang, Yu-Xia; Pan, Chang-Gui; Tian, Fei; Martin, Francis L

2017-02-01

Traditional duckweed toxicity tests only measure plant growth inhibition as an endpoint, with limited effects-based data. The present study aimed to investigate whether Fourier-transform infrared (FTIR) spectroscopy could enhance the duckweed (Lemna minor L.) toxicity test. Four chemicals (Cu, Cd, atrazine, and acetochlor) and 4 metal-containing industrial wastewater samples were tested. After exposure of duckweed to the chemicals, standard toxicity endpoints (frond number and chlorophyll content) were determined; the fronds were also interrogated using FTIR spectroscopy under optimized test conditions. Biochemical alterations associated with each treatment were assessed and further analyzed by multivariate analysis. The results showed that comparable x% of effective concentration (ECx) values could be achieved based on FTIR spectroscopy in comparison with those based on traditional toxicity endpoints. Biochemical alterations associated with different doses of toxicant were mainly attributed to lipid, protein, nucleic acid, and carbohydrate structural changes, which helped to explain toxic mechanisms. With the help of multivariate analysis, separation of clusters related to different exposure doses could be achieved. The present study is the first to show successful application of FTIR spectroscopy in standard duckweed toxicity tests with biochemical alterations as new endpoints. Environ Toxicol Chem 2017;36:346-353. © 2016 SETAC. © 2016 SETAC.

Photodegradation kinetics, transformation, and toxicity prediction of ketoprofen, carprofen, and diclofenac acid in aqueous solutions.

Science.gov (United States)

Li, Jian; Ma, Li-Yun; Li, Lu-Shuang; Xu, Li

2017-12-01

Photodegradation of 3 commonly used nonsteroidal anti-inflammatory drugs, ketoprofen, carprofen, and diclofenac acid, was conducted under ultraviolet (UV) irradiation. The kinetic results showed that the 3 pharmaceuticals obeyed the first-order reaction with decreasing rate constants of 1.54 × 10 -4 , 5.91 × 10 -5 , and 7.78 × 10 -6  s -1 for carprofen, ketoprofen, and diclofenac acid, respectively. Moreover, the main transformation products were identified by ion-pair liquid-liquid extraction combined with injection port derivatization-gas chromatography-mass spectrometry and high-performance liquid chromatography-quadrupole-time of flight mass spectrometric analysis. There were 8, 3, and 6 transformation products identified for ketoprofen, carprofen, and diclofenac acid, respectively. Decarboxylation, dechlorination, oxidation, demethylation, esterification, and cyclization were proposed to be associated with the transformation of the 3 pharmaceuticals. Toxicity prediction of the transformation products was conducted on the EPI Suite software based on ECOSAR model, and the results indicate that some of the transformation products were more toxic than the parent compounds. The present study provides the foundation to understand the transformation behavior of the studied pharmaceuticals under UV irradiation. Environ Toxicol Chem 2017;36:3232-3239. © 2017 SETAC. © 2017 SETAC.

Spectators or participants: How can SETAC become more engaged in international climate change research programs?

Science.gov (United States)

Stahl, Ralph G; Stauber, Jennifer L; Clements, William H

2017-08-01

Environmental toxicologists and chemists have been crucial to evaluating the chemical fate and toxicological effects of environmental contaminants, including chlorinated pesticides, before and after Rachel Carson's publication of Silent Spring in 1962. Like chlorinated pesticides previously, global climate change is widely considered to be one of the most important environmental challenges of our time. Over the past 30 yr, climate scientists and modelers have shown that greenhouse gases such as CO 2 and CH 4 cause radiative forcing (climate forcing) and lead to increased global temperatures. Despite significant climate change research efforts worldwide, the climate science community has overlooked potential problems associated with chemical contaminants, in particular how climate change could magnify the ecological consequences of their use and disposal. It is conceivable that the impacts of legacy or new chemical contaminants on wildlife and humans may be exacerbated when climate changes, especially if global temperatures rise as predicted. This lack of attention to chemical contaminants represents an opportunity for environmental toxicologists and chemists to become part of the global research program, and our objective is to highlight the importance of and ways for that to occur. Environ Toxicol Chem 2017;36:1971-1977. © 2017 SETAC. © 2017 SETAC.

Effects of in ovo exposure to 3,3',4,4'-tetrachlorobiphenyl (PCB 77) on heart development in tree swallow (Tachycineta bicolor).

Science.gov (United States)

Carro, Tiffany; Walker, Mary K; Dean, Karen M; Ottinger, Mary Ann

2018-01-01

Tree swallow (Tachycineta bicolor) eggs from 2 uncontaminated sites, the Patuxent Research Refuge (Laurel, MD, USA) and the Cobleskill Reservoir (Cobleskill, NY, USA) were dosed with polychlorinated biphenyl (PCB) 77 to evaluate effects on the developing cardiovascular system. To ensure embryonic viability, treatments were administered into the air cell at embryonic day 2.5 including: untreated (control), vehicle (filtered sterilized fatty acid mixture), 100 ng/g and 1000 ng/g egg. Eggs were dosed in the field with 0.2 μL/egg, returned to the nest, collected at embryonic day 13, hatched in the laboratory, and necropsied. The PCB 77-treated hatchlings were compared with uninjected, vehicle-injected, and environmentally exposed hatchlings collected from a PCB-contaminated Upper Hudson River (NY, USA) site. The PCB 77-treated embryos showed no effects on hatching success or hatchling mortality, heart index, or morphological measures of 4 distinct heart layers (heart width, length, septal thickness, total and ventricular cavity area) compared with controls. Hatchlings that had received PCB 77 exhibited increased incidence of a cardiomyopathy and absence of the ventricular heart wall compact layer (Chi square test; p PCB 77 resulted in distinct cardiomyopathy has implications for long-term individual fitness. Environ Toxicol Chem 2018;37:116-125. © 2017 SETAC. © 2017 SETAC.

Long-term exposure to gold nanoparticles accelerates larval metamorphosis without affecting mass in wood frogs (Lithobates sylvaticus) at environmentally relevant concentrations.

Science.gov (United States)

Fong, Peter P; Thompson, Lucas B; Carfagno, Gerardo L F; Sitton, Andrea J

2016-09-01

Nanoparticles are environmental contaminants of emerging concern. Exposure to engineered nanoparticles has been shown to have detrimental effects on aquatic organisms. The authors synthesized gold nanoparticles (18.1 ± 3.5 nm) and tested their effects on time to and weight at metamorphosis in wood frog (Lithobates sylvaticus) tadpoles, a species known to be sensitive to environmental stressors. Continuous exposure to all concentrations of gold nanoparticles (0.05 pM, 0.5 pM, and 5 pM in particles) for up to 55 d significantly reduced time to metamorphosis by as much as an average of 3 d (p metamorphosis. The approximately 18-nm gold nanoparticles used were metastable in dechlorinated tap water, resulting in a change in surface charge and aggregation over time, leading to negatively charged aggregates that were on the order of 60 nm to 110 nm. Nanoparticle aggregation could exacerbate the effect on time to metamorphosis. To the authors' knowledge, the present study is the first report on the effect of engineered nanoparticles of any kind on life-history variables in an amphibian, a taxonomic group that has been declining globally for at least 25 yr. Environ Toxicol Chem 2016;35:2304-2310. © 2016 SETAC. © 2016 SETAC.

Barley root hair growth and morphology in soil, sand, and water solution media and relationship with nickel toxicity.

Science.gov (United States)

Lin, Yanqing; Allen, Herbert E; Di Toro, Dominic M

2016-08-01

Barley, Hordeum vulgare (Doyce), was grown in the 3 media of soil, hydroponic sand solution (sand), and hydroponic water solution (water) culture at the same environmental conditions for 4 d. Barley roots were scanned, and root morphology was analyzed. Plants grown in the 3 media had different root morphology and nickel (Ni) toxicity response. Root elongations and total root lengths followed the sequence soil > sand > water. Plants grown in water culture were more sensitive to Ni toxicity and had greater root hair length than those from soil and sand cultures, which increased root surface area. The unit root surface area as root surface area per centimeter of length of root followed the sequence water > sand > soil and was found to be related with root elongation. Including the unit root surface area, the difference in root elongation and 50% effective concentration were diminished, and percentage of root elongations can be improved with a root mean square error approximately 10% for plants grown in different media. Because the unit root surface area of plants in sand culture is closer to that in soil culture, the sand culture method, not water culture, is recommended for toxicity parameter estimation. Environ Toxicol Chem 2016;35:2125-2133. © 2016 SETAC. © 2016 SETAC.

A UniChem and electron momentum spectroscopy investigations into the valence electronic structure of trans 1,3 butadiene

Energy Technology Data Exchange (ETDEWEB)

Michalewicz, M.T. [CSIRO, Supercomputing Support Group, Carlton, VIC (Australia). Division of Information Technology; Winkler, D.A. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Clayton, VIC (Australia). Div. of Chemical Physics; Brunger, M.J.; McCarthy, L.E. [Flinders Univ. of South Australia, Bedford Park, SA (Australia). School of Physical Sciences; Von Niessen, W. [Flinders Univ. of South Australia, Bedford Park, SA (Australia). School of Physical Sciences

1996-09-01

The experimental (e,2e) coincidence spectroscopy, known as electron momentum spectroscopy (EMS) was applied to the trans 1,3 butadiene (C{sub 4}H{sub 6}) molecule with detailed binding energy spectra and orbital momentum distributions (MDs) being measured. A small selection of this data is presented. The usage of UniChem computational chemistry codes for the Flinders-developed AMOLD program allows to calculate theoretical MDs for each orbital, to help elucidate the valence electronic structure of butadiene. The results of the many-body Green`s function calculation is also presented, to the ADC(3) level, for the binding energies and spectroscopic factors of the respective orbitals of C{sub 4}H{sub 6}. A critical comparison between the experimental and theoretical MDs allows to determine the optimum wavefunction from the basis sets studied. The determination of the wavefunction then allows to make further use of the UniChem package to derive butadiene`s chemically interesting molecular properties. A summary of these results and comparison of them with the previous results of other workers is presented. 23 refs., 2 tabs., 2 figs.

A UniChem and electron momentum spectroscopy investigations into the valence electronic structure of trans 1,3 butadiene

International Nuclear Information System (INIS)

Michalewicz, M.T.; Winkler, D.A.; Brunger, M.J.; McCarthy, L.E.; Von Niessen, W.

1996-09-01

The experimental (e,2e) coincidence spectroscopy, known as electron momentum spectroscopy (EMS) was applied to the trans 1,3 butadiene (C 4 H 6 ) molecule with detailed binding energy spectra and orbital momentum distributions (MDs) being measured. A small selection of this data is presented. The usage of UniChem computational chemistry codes for the Flinders-developed AMOLD program allows to calculate theoretical MDs for each orbital, to help elucidate the valence electronic structure of butadiene. The results of the many-body Green's function calculation is also presented, to the ADC(3) level, for the binding energies and spectroscopic factors of the respective orbitals of C 4 H 6 . A critical comparison between the experimental and theoretical MDs allows to determine the optimum wavefunction from the basis sets studied. The determination of the wavefunction then allows to make further use of the UniChem package to derive butadiene's chemically interesting molecular properties. A summary of these results and comparison of them with the previous results of other workers is presented. 23 refs., 2 tabs., 2 figs

Sorption and desorption of glyphosate in Mollisols and Ultisols soils of Argentina.

Science.gov (United States)

Gómez Ortiz, Ana Maria; Okada, Elena; Bedmar, Francisco; Costa, José Luis

2017-10-01

In Argentina, glyphosate use has increased exponentially in recent years as a result of the widespread adoption of no-till management combined with genetically modified glyphosate-resistant crops. This massive use of glyphosate has created concern about its potential environmental impact. Sorption-desorption of glyphosate was studied in 3 Argentinean soils with contrasting characteristics. Glyphosate sorption isotherms were modeled using the Freundlich equation to estimate the sorption coefficient (K f ). Glyphosate sorption was high, and the K f varied from 115.6 to 1612 mg 1-1/n L 1/n /kg. Cerro Azul soil had the highest glyphosate sorption capacity as a result of a combination of factors such as higher clay content, cation exchange capacity, total iron, and aluminum oxides, and lower available phosphorus and pH. Desorption isotherms were also modeled using the Freundlich equation. In general, desorption was very low (glyphosate strongly sorbs to the soils and that it is almost an irreversible process. Anguil soil had a significantly higher desorption coefficient (K fd ) than the other soils, associated with its lower clay content and higher pH and phosphorus. Glyphosate high sorption and low desorption to the studied soils may prevent groundwater contamination. However, it may also affect its bioavailability, increasing its persistence and favoring its accumulation in the environment. The results of the present study contribute to the knowledge and characterization of glyphosate retention in different soils. Environ Toxicol Chem 2017;36:2587-2592. © 2017 SETAC. © 2017 SETAC.

Comparison of lipid peroxidation and catalase response in invasive dreissenid mussels exposed to single and multiple stressors.

Science.gov (United States)

Nowicki, Carly J; Kashian, Donna R

2018-02-14

Dreissenid mussels Dreissena bugensis (quagga mussel) and Dreissena polymorpha (zebra mussel) are prolific invasive species to the freshwaters of the United States and Western Europe. In the Great Lakes, D. polymorpha has initially dominated the system since its invasion in the mid-1980s; however, recently D. bugensis has displaced D. polymorpha as the dominant species. Dreissena bugensis has several competitive advantages over D. polymorpha, including greater tolerances to deeper and colder waters and lower respiration rates. Nevertheless, physiological differences between the species remain largely unknown. The oxidative stress response is a mechanism used by all organisms to mitigate environmental stress by reducing oxygen radicals in the body, and comparing this mechanism between similar species can be useful for understanding how different species compete in aquatic environments. We compared oxidative stress biomarkers (lipid peroxidation [LPO] and catalase [CAT] activity) in mussels after exposure to 4 stressors (i.e., high densities, temperature, hypoxia, and polychlorinated biphenyls [PCBs]) independently and in combinations of 2 stressors. Overall, D. bugensis had lower LPO and CAT activity than D. polymorpha when exposed to single stressors; however, in multiple stressor treatments D. bugensis had increased LPO, especially with high temperatures and PCBs. The lower lipid damage in D. bugensis compared with D. polymorpha under single stressor conditions may come at the cost of the ability to respond to multiple stressors. Environ Toxicol Chem 2018;9999:1-12. © 2018 SETAC. © 2018 SETAC.

Effects of metals on enantioselective toxicity and biotransformation of cis-bifenthrin in zebrafish.

Science.gov (United States)

Yang, Ye; Ji, Dapeng; Huang, Xin; Zhang, Jianyun; Liu, Jing

2017-08-01

Co-occurrence of pyrethroids and metals in watersheds previously has been reported to pose great risk to aquatic species. Pyrethroids are a class of chiral insecticides that have been shown to have enantioselective toxicity and biotransformation. However, the influence of metals on enantioselectivity of pyrethroids has not yet been evaluated. In the present study, the effects of cadmium (Cd), copper (Cu), and lead (Pb) on the enantioselective toxicity and metabolism of cis-bifenthrin (cis-BF) were investigated in zebrafish at environmentally relevant concentrations. The addition of Cd, Cu, or Pb significantly increased the mortality of zebrafish in racemate and R-enantiomer of cis-BF-treated groups. In rac-cis-BF- or 1R-cis-BF-treated groups, the addition of Cd, Cu, or Pb caused a decrease in enantiomeric fraction (EF) and an increased ratio of R-enantiomer residues in zebrafish. In 1S-cis-BF-treated groups, coexposure to Cd led to a lower EF and decreased residue levels of S-enantiomer. In addition, coexposure to the 3 metals resulted in different biodegradation characteristics of each enantiomer accompanied with differential changes in the expression of cytochrome P450 (CYP)1, CYP2, and CYP3 genes, which might be responsible for the enantioselective biodegradation of cis-BF in zebrafish. These results suggest that the influence of coexistent metals should be considered in the ecological risk assessment of chiral pyrethroids in aquatic environments. Environ Toxicol Chem 2017;36:2139-2146. © 2017 SETAC. © 2017 SETAC.

Diet quality affects chemical tolerance in the freshwater snail Lymnaea stagnalis.

Science.gov (United States)

Fidder, Bridgette N; Reátegui-Zirena, Evelyn G; Salice, Christopher J

2018-04-01

Organisms generally select high-quality diets to obtain maximal energy while devoting the least amount of time and energy. Diets, however, can vary in natural systems. In ecotoxicological testing, the effect of diet type on organismal responses to toxicants has not been explored despite the potential for dietary effects to influence toxicological endpoints. We first evaluated diet quality using growth rate and sensitivity to the fungicide pyraclostrobin of Lymnaea stagnalis fed lettuce (common laboratory diet), turtle pellets (high nutrient composition), and a combination diet of both food items. We also measured the macronutrient content of snails raised on the multiple diets to determine how diet may have impacted energy allocation patterns. Finally, we evaluated whether snails discernibly preferred a particular diet. Snails fed high-nutrient and combination diets grew larger overall than snails fed a lettuce-only diet. Snails fed the high-nutrient and combination diets, both juvenile and adult, were significantly more tolerant to pyraclostrobin than snails fed lettuce. When measured for macronutrient content, snails raised on high-nutrient and combination diets had significantly higher carbohydrate content than snails fed lettuce. Despite the strong effects of diet type, snails did not exhibit a clear diet choice in preference trials. Dietary composition clearly influences growth rate, sensitivity, and macronutrient content of Lymnaea stagnalis. These results suggest that the nutritional environment has potentially strong impacts on toxicant sensitivity. Environ Toxicol Chem 2018;37:1158-1167. © 2017 SETAC. © 2017 SETAC.

Nontarget effects of ivermectin residues on earthworms and springtails dwelling beneath dung of treated cattle in four countries.

Science.gov (United States)

Scheffczyk, Adam; Floate, Kevin D; Blanckenhorn, Wolf U; Düring, Rolf-Alexander; Klockner, Andrea; Lahr, Joost; Lumaret, Jean-Pierre; Salamon, Jörg-Alfred; Tixier, Thomas; Wohde, Manuel; Römbke, Jörg

2016-08-01

The authorization of veterinary medicinal products requires that they be assessed for nontarget effects in the environment. Numerous field studies have assessed these effects on dung organisms. However, few studies have examined effects on soil-dwelling organisms, which might be exposed to veterinary medicinal product residues released during dung degradation. The authors compared the abundance of earthworms and springtails in soil beneath dung from untreated cattle and from cattle treated 0 d, 3 d, 7 d, 14 d, and 28 d previously with ivermectin. Study sites were located in different ecoregions in Switzerland (Continental), The Netherlands (Atlantic), France (Mediterranean), and Canada (Northern Mixed Grassland). Samples were collected using standard methods from 1 mo to 12 mo after pat deposition. Ivermectin concentrations in soil beneath dung pats ranged from 0.02 mg/kg dry weight (3 mo) to typically Earthworms were abundant and species-rich at the Swiss and Dutch sites, less common with fewer species at the French site, and essentially absent at the Canadian site. Diverse but highly variable communities of springtails were present at all sites. Overall, results showed little effect of residues on either earthworms or springtails. The authors recommend that inclusion of soil organisms in field studies to assess the nontarget effects of veterinary medicinal products be required only if earthworms or springtails exhibit sensitivity to the product in laboratory tests. Environ Toxicol Chem 2016;35:1959-1969. © 2015 SETAC. © 2015 SETAC.

Aspectos toxicológicos e ocorrência dos bifenilos policlorados em alimentos Toxicological aspects and occurrence of polychlorinated biphenyls in food

Directory of Open Access Journals (Sweden)

Susana Mohr

2012-03-01

Full Text Available Os PCBs são compostos orgânicos sintéticos que foram muito utilizados na indústria como fluídos dielétricos em transformadores e capacitores, tintas e óleos lubrificantes hidráulicos. Após serem detectados no meio ambiente no final dos anos 60, em seguida foram identificados como contaminantes de todo o ecossistema global, incluindo o ar, água, solo, plantas, animais, seres humanos e alimentos, o que levou à sua proibição em 1977, nos Estados Unidos, e, em 1981, no Brasil. Porém, sua utilização ainda é permitida no nosso país em equipamentos eletrônicos antigos, até que seja realizada a sua substituição por produto isento de PCBs. Esse fato tem resultado em diversos episódios de utilização, armazenamento e descarte inadequados, contaminando o meio ambiente, os animais, os seres humanos e toda a cadeia alimentar. Estudos demonstram que esses compostos são capazes de causar relevantes alterações, tais como neurotoxicidade, disrupção endócrina, imunossupressão, entre outros. Segundo a IARC, os PCBs estão classificados no Grupo 2A (provavelmente carcinogênicos para seres humanos, com exceção do PCB 126, que pertence ao Grupo 1 (carcinogênico para seres humanos. Como estes compostos são altamente lipofílicos, acumulam-se na cadeia alimentar e têm sido detectados nos mais diversos tipos de alimentos com bastante frequência, sendo esta a principal fonte de contaminação dos seres humanos. Esta revisão bibliográfica tem por objetivo apresentar os principais aspectos relacionados aos bifenilos policlorados em alimentos, incluindo suas características, aspectos toxicológicos e ocorrência.PCBs are synthetic organic compounds that were widely used in industry as dielectric fluids in transformers and capacitors, paints and lubricants hydraulic oils. After being detected in the environment on the end of 60, then they were identified as contaminants in the whole ecosystem, including the air, water, soil, plants

Butyltin compounds in the oyster, Saccostrea cucculata, from the West Coast of India

Digital Repository Service at National Institute of Oceanography (India)

Garg, A.; Bhosle, N.B.

: 26 August 2005 Correspondence to: N. B. Bhosle Bull. Environ. Contam. Toxicol. (2005) 75:982–988 © 2005 Springer Science+Business Media, Inc. DOI: 10.1007/s00128-005-0846-1 982 983 984 985 986 987 988 ...

ChemCam results from the Shaler outcrop in Gale crater, Mars

Science.gov (United States)

Anderson, Ryan B.; Bridges, J.C.; Williams, A.; Edgar, L.; Ollila, A.; Williams, J.; Nachon, Marion; Mangold, N.; Fisk, M.; Schieber, J.; Gupta, S.; Dromart, G.; Wiens, R.; Le Mouélic, Stéphane; Forni, O.; Lanza, N.; Mezzacappa, Alissa; Sautter, V.; Blaney, D.; Clark, B.; Clegg, S.; Gasnault, O.; Lasue, J.; Léveillé, Richard; Lewin, E.; Lewis, K.W.; Maurice, S.; Newsom, H.; Schwenzer, S.P.; Vaniman, D.

2015-01-01

The ChemCam campaign at the fluvial sedimentary outcrop “Shaler” resulted in observations of 28 non-soil targets, 26 of which included active laser induced breakdown spectroscopy (LIBS), and all of which included Remote Micro-Imager (RMI) images. The Shaler outcrop can be divided into seven facies based on grain size, texture, color, resistance to erosion, and sedimentary structures. The ChemCam observations cover Facies 3 through 7. For all targets, the majority of the grains were below the limit of the RMI resolution, but many targets had a portion of resolvable grains coarser than ∼0.5 mm. The Shaler facies show significant scatter in LIBS spectra and compositions from point to point, but several key compositional trends are apparent, most notably in the average K2O content of the observed facies. Facies 3 is lower in K2O than the other facies and is similar in composition to the “snake,” a clastic dike that occurs lower in the Yellowknife Bay stratigraphic section. Facies 7 is enriched in K2O relative to the other facies and shows some compositional and textural similarities to float rocks near Yellowknife Bay. The remaining facies (4, 5, and 6) are similar in composition to the Sheepbed and Gillespie Lake members, although the Shaler facies have slightly elevated K2O and FeOT. Several analysis points within Shaler suggest the presence of feldspars, though these points have excess FeOT which suggests the presence of Fe oxide cement or inclusions. The majority of LIBS analyses have compositions which indicate that they are mixtures of pyroxene and feldspar. The Shaler feldspathic compositions are more alkaline than typical feldspars from shergottites, suggesting an alkaline basaltic source region, particularly for the K2O-enriched Facies 7. Apart from possible iron-oxide cement, there is little evidence for chemical alteration at Shaler, although calcium-sulfate veins comparable to those observed lower in the stratigraphic section are present. The

Theoretical modeling and analysis of the emission spectra of a ChemCam standard: Basalt BIR-1A

Energy Technology Data Exchange (ETDEWEB)

Colgan, J. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Judge, E.J. [Chemical Diagnostics and Engineering, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Johns, H.M.; Kilcrease, D.P. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Barefield, J.E. [Chemical Diagnostics and Engineering, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); McInroy, R. [Physical Chemistry and Applied Spectroscopy, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Hakel, P. [Computational Physics Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Wiens, R.C. [Space and Remote Sensing Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Clegg, S.M. [Physical Chemistry and Applied Spectroscopy, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2015-08-01

We report on efforts to perform theoretical modeling of the emission spectrum measured from a basalt sample. We compare our calculations with measurements that were made to provide standards for the ChemCam instrument on the Mars Science Laboratory. We find that to obtain good agreement between modeling and the measurement, it is necessary to determine atomic and ionic level populations via a multi-element approach in which the free electron density that is created influences all the species within the plasma. Calculations that consider each element separately are found to be in poorer agreement with the measured spectrum, indicating that the ‘matrix effect’ term often used to describe the influence of other species on the emission spectrum from a given element is due to the influence of the global electron density of the plasma. We explore the emission features in both the visible and near-infrared wavelength ranges, and also examine radiation transport effects for some of the most intense features found in the basalt spectrum. Finally, we also provide comparisons of the ChemCam measurement with new high-resolution spectral measurements. - Highlights: • LIBS basalt spectrum • Ab-initio theoretical modeling • Discussion of matrix effects • Discussion of radiation transport effects • High-resolution measurements of Basalt.

Chemistry of diagenetic features analyzed by ChemCam at Pahrump Hills, Gale crater, Mars

Science.gov (United States)

Nachon, Marion; Mangold, Nicolas; Forni, Olivier; Kah, Linda C.; Cousin, Agnes; Wiens, Roger C.; Anderson, Ryan; Blaney, Diana L.; Blank, Jen G.; Calef, Fred J.; Clegg, Samuel M.; Fabre, Cecile; Fisk, Martin R.; Gasnault, Olivier; Grotzinger, John P.; Kronyak, Rachel; Lanza, Nina L.; Lasue, Jeremie; Le Deit, Laetitia; Le Mouelic, Stephane; Maurice, Sylvestre; Meslin, Pierre-Yves; Oehler, D. Z.; Payre, Valerie; Rapin, William; Schroder, Susanne; Stack, Katherine M.; Sumner, Dawn

2017-01-01

The Curiosity rover's campaign at Pahrump Hills provides the first analyses of lower Mount Sharp strata. Here we report ChemCam elemental composition of a diverse assemblage of post-depositional features embedded in, or cross-cutting, the host rock. ChemCam results demonstrate their compositional diversity, especially compared to the surrounding host rock: (i) Dendritic aggregates and relief enhanced features, characterized by a magnesium enhancement and sulfur detection, and interpreted as Mg-sulfates; (ii) A localized observation that displays iron enrichment associated with sulfur, interpreted as Fe-sulfate; (iii) Dark raised ridges with varying Mg- and Ca-enriched compositions compared to host rock; (iv) Several dark-toned veins with calcium enhancement associated with fluorine detection, interpreted as fluorite veins. (v) Light-toned veins with enhanced calcium associated with sulfur detection, and interpreted as Ca-sulfates. The diversity of the Pahrump Hills diagenetic assemblage suggests a complex post-depositional history for fine-grained sediments for which the origin has been interpreted as fluvial and lacustrine. Assessment of the spatial and relative temporal distribution of these features shows that the Mg-sulfate features are predominant in the lower part of the section, suggesting local modification of the sediments by early diagenetic fluids. In contrast, light-toned Ca-sulfate veins occur in the whole section and cross-cut all other features. A relatively late stage shift in geochemical conditions could explain this observation. The Pahrump Hills diagenetic features have no equivalent compared to targets analyzed in other locations at Gale crater. Only the light-toned Ca-sulfate veins are present elsewhere, along Curiosity's path, suggesting they formed through a common late-stage process that occurred at over a broad area.

Feasibility of Integration of Selected Aspects of (CBA) Chemistry, (CHEMS) Chemistry and (PSSC) Physics into a Two Year Physical Science Sequence.

Science.gov (United States)

Fiasca, Michael Aldo

Compared, for selected outcomes, were integrated chemistry-physics courses with chemistry and physics courses taught separately. Three classes studying integrated Physical Science Study Committee (PSSC)-Chemical Bond Approach (CBA), and three classes studying integrated Physical Science Study Committee-Chemical Education Materials Study (CHEMS)…

The ChemCam Instrument Suite on the Mars Science Laboratory (MSL) Rover: Science Objectives and Mast Unit Description

Science.gov (United States)

Maurice, S.; Wiens, R.C.; Saccoccio, M.; Barraclough, B.; Gasnault, O.; Forni, O.; Mangold, N.; Baratoux, D.; Bender, S.; Berger, G.; Bernardin, J.; Berthé, M.; Bridges, N.; Blaney, D.; Bouyé, M.; Caïs, P.; Clark, B.; Clegg, S.; Cousin, A.; Cremers, D.; Cros, A.; DeFlores, L.; Derycke, C.; Dingler, B.; Dromart, G.; Dubois, B.; Dupieux, M.; Durand, E.; d'Uston, L.; Fabre, C.; Faure, B.; Gaboriaud, A.; Gharsa, T.; Herkenhoff, K.; Kan, E.; Kirkland, L.; Kouach, D.; Lacour, J.-L.; Langevin, Y.; Lasue, J.; Le Mouélic, S.; Lescure, M.; Lewin, E.; Limonadi, D.; Manhès, G.; Mauchien, P.; McKay, C.; Meslin, P.-Y.; Michel, Y.; Miller, E.; Newsom, Horton E.; Orttner, G.; Paillet, A.; Parès, L.; Parot, Y.; Pérez, R.; Pinet, P.; Poitrasson, F.; Quertier, B.; Sallé, B.; Sotin, Christophe; Sautter, V.; Séran, H.; Simmonds, J.J.; Sirven, J.-B.; Stiglich, R.; Striebig, N.; Thocaven, J.-J.; Toplis, M.J.; Vaniman, D.

2012-01-01

ChemCam is a remote sensing instrument suite on board the "Curiosity" rover (NASA) that uses Laser-Induced Breakdown Spectroscopy (LIBS) to provide the elemental composition of soils and rocks at the surface of Mars from a distance of 1.3 to 7 m, and a telescopic imager to return high resolution context and micro-images at distances greater than 1.16 m. We describe five analytical capabilities: rock classification, quantitative composition, depth profiling, context imaging, and passive spectroscopy. They serve as a toolbox to address most of the science questions at Gale crater. ChemCam consists of a Mast-Unit (laser, telescope, camera, and electronics) and a Body-Unit (spectrometers, digital processing unit, and optical demultiplexer), which are connected by an optical fiber and an electrical interface. We then report on the development, integration, and testing of the Mast-Unit, and summarize some key characteristics of ChemCam. This confirmed that nominal or better than nominal performances were achieved for critical parameters, in particular power density (>1 GW/cm2). The analysis spot diameter varies from 350 μm at 2 m to 550 μm at 7 m distance. For remote imaging, the camera field of view is 20 mrad for 1024×1024 pixels. Field tests demonstrated that the resolution (˜90 μrad) made it possible to identify laser shots on a wide variety of images. This is sufficient for visualizing laser shot pits and textures of rocks and soils. An auto-exposure capability optimizes the dynamical range of the images. Dedicated hardware and software focus the telescope, with precision that is appropriate for the LIBS and imaging depths-of-field. The light emitted by the plasma is collected and sent to the Body-Unit via a 6 m optical fiber. The companion to this paper (Wiens et al. this issue) reports on the development of the Body-Unit, on the analysis of the emitted light, and on the good match between instrument performance and science specifications.

Comparative safety testing of genetically modified foods in a 90-day rat feeding study design allowing the distinction between primary and secondary effects of the new genetic event

DEFF Research Database (Denmark)

Knudsen, Ib; Poulsen, Morten

2007-01-01

., Frenzel, T., Danier, J., Rychlik, M., Shu, Q., Emami, K., Taylor, M., Gatehouse, A., Engel, K.-H., Knudsen, I., 2007a. Safety testing of GM-rice expressing PHA-E lectin using a new animal test design. Food Chem. Toxicol. 45, 364-377; Poulsen, M., Kroghsbo, S., Schroder, M., Wilcks, A., Jacobsen, H...... to separate potentially unintended effects of the novel gene product from other unintended effects at the level of intake defined in the test and within the remit of the test. Recommendations for further work necessary in the field are given.......This article discusses the wider experiences regarding the usefulness of the 90-day rat feeding study for the testing of whole foods from genetically modified (GM) plant based on data from a recent EU-project [Poulsen, M., Schroder, M., Wilcks, A., Kroghsbo, S., Lindecrona, R.H., Miller, A...

Hypochlorous acid-mediated oxidation of lipid components and antioxidants present in low-density lipoproteins

DEFF Research Database (Denmark)

Pattison, David I; Hawkins, Clare Louise; Davies, Michael Jonathan

2003-01-01

Oxidation of low-density lipoproteins (LDL) is believed to contribute to the increased uptake of LDL by macrophages, which is an early event in atherosclerosis. Hypochlorous acid (HOCl) has been implicated as one of the major oxidants involved in these processes. In a previous study, the rates...... of reaction of HOCl with the reactive sites in proteins were investigated (Pattison, D. I., and Davies, M. J. (2001) Chem. Res. Toxicol. 14, 1453-1464). The work presented here expands on those studies to determine absolute second-order rate constants for the reactions of HOCl with various lipid components...... nitrogen- and carbon-centered radicals. Subsequent reactions of these species may induce oxidation of the LDL lipid component. In contrast, phosphoryl-choline reacted much more slowly (k Reaction of HOCl with 3-pentenoic acid was used as a model of lipid double bonds...

A statistical downscaling approach for roadside NO2 concentrations: Application to a WRF-Chem study for Berlin

Science.gov (United States)

Kuik, Friderike; Lauer, Axel; von Schneidemesser, Erika; Butler, Tim

2017-04-01

Many European cities continue to struggle with meeting the European air quality limits for NO2. In Berlin, Germany, most of the exceedances in NO2 recorded at monitoring sites near busy roads can be largely attributed to emissions from traffic. In order to assess the impact of changes in traffic emissions on air quality at policy relevant scales, we combine the regional atmosphere-chemistry transport model WRF-Chem at a resolution of 1kmx1km with a statistical downscaling approach. Here, we build on the recently published study evaluating the performance of a WRF-Chem setup in representing observed urban background NO2 concentrations from Kuik et al. (2016) and extend this setup by developing and testing an approach to statistically downscale simulated urban background NO2 concentrations to street level. The approach uses a multilinear regression model to relate roadside NO2 concentrations observed with the municipal monitoring network with observed NO2 concentrations at urban background sites and observed traffic counts. For this, the urban background NO2 concentrations are decomposed into a long term, a synoptic and a diurnal component using the Kolmogorov-Zurbenko filtering method. We estimate the coefficients of the regression model for five different roadside stations in Berlin representing different street types. In a next step we combine the coefficients with simulated urban background concentrations and observed traffic counts, in order to estimate roadside NO2 concentrations based on the results obtained with WRF-Chem at the five selected stations. In a third step, we extrapolate the NO2 concentrations to all major roads in Berlin. The latter is based on available data for Berlin of daily mean traffic counts, diurnal and weekly cycles of traffic as well as simulated urban background NO2 concentrations. We evaluate the NO2 concentrations estimated with this method at street level for Berlin with additional observational data from stationary measurements and

Interpreting aerosol lifetimes using the GEOS-Chem model and constraints from radionuclide measurements

Energy Technology Data Exchange (ETDEWEB)

Croft, B. [Dalhousie Univ., Halifax (Canada). Dept. of Physics and Atmospheric Science; Pierce, J.R. [Dalhousie Univ., Halifax (Canada). Dept. of Physics and Atmospheric Science; Colorado State Univ., Fort Collins, CO (United States); Martin, R.V. [Dalhousie Univ., Halifax (Canada). Dept. of Physics and Atmospheric Science; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

2014-07-01

Aerosol removal processes control global aerosol abundance, but the rate of that removal remains uncertain. A recent study of aerosol-bound radionuclide measurements after the Fukushima Daiichi nuclear power plant accident documents {sup 137}Cs removal (e-folding) times of 10.0-13.9 days, suggesting that mean aerosol lifetimes in the range of 3-7 days in global models might be too short by a factor of two. In this study, we attribute this discrepancy to differences between the e-folding and mean aerosol lifetimes. We implement a simulation of {sup 137}Cs and {sup 133}Xe into the GEOS-Chem chemical transport model and examine the removal rates for the Fukushima case. We find a general consistency between modelled and measured e-folding times. The simulated {sup 137}Cs global burden e-folding time is about 14 days. However, the simulated mean lifetime of aerosol-bound {sup 137}Cs over a 6-month post-accident period is only 1.8 days. We find that the mean lifetime depends strongly on the removal rates in the first few days after emissions, before the aerosols leave the boundary layer and are transported to altitudes and latitudes where lifetimes with respect to wet removal are longer by a few orders of magnitude. We present sensitivity simulations that demonstrate the influence of differences in altitude and location of the radionuclides on the mean lifetime. Global mean lifetimes are shown to strongly depend on the altitude of injection. The global mean {sup 137}Cs lifetime is more than one order of magnitude greater for the injection at 7 km than into the boundary layer above the Fukushima site. Instantaneous removal rates are slower during the first few days after the emissions for a free tropospheric versus boundary layer injection and this strongly controls the mean lifetimes. Global mean aerosol lifetimes for the GEOS-Chem model are 3-6 days, which is longer than that for the {sup 137}Cs injected at the Fukushima site (likely due to precipitation shortly after

Temperature-referenced high-sensitivity point-probe optical fiber chem-sensors based on cladding etched fiber Bragg gratings

OpenAIRE

Zhou, Kaiming; Chen, Xianfeng F.; Zhang, Lin; Bennion, Ian

2004-01-01

Point-probe optical fiber chem-sensors have been implemented using cladding etched fiber Bragg gratings. The sensors possess refractive index sensing capability that can be utilized to measure chemical concentrations. The Bragg wavelength shift reaches 8 nm when the index of surrounding medium changes from 1.33 to 1.44, giving maximum sensitivity more than 10 times higher than that of previously reported devices. More importantly, the dual-grating configuration of the point-probe sensors offe...

Pre-flight calibration and initial data processing for the ChemCam laser-induced breakdown spectroscopy instrument on the Mars Science Laboratory rover

Energy Technology Data Exchange (ETDEWEB)

Wiens, R.C., E-mail: rwiens@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Maurice, S.; Lasue, J.; Forni, O. [Institut de Recherche en Astrophysique et Planetologie, Toulouse (France); Anderson, R.B. [United States Geological Survey, Flagstaff, AZ (United States); Clegg, S. [Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Bender, S. [Planetary Science Institute, Tucson, AZ (United States); Blaney, D. [Jet Propulsion Laboratory, Pasadena, CA (United States); Barraclough, B.L. [Planetary Science Institute, Tucson, AZ (United States); Cousin, A. [Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Institut de Recherche en Astrophysique et Planetologie, Toulouse (France); Deflores, L. [Jet Propulsion Laboratory, Pasadena, CA (United States); Delapp, D. [Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Dyar, M.D. [Mount Holyoke College, South Hadley, MA (United States); Fabre, C. [Georessources, Nancy (France); Gasnault, O. [Institut de Recherche en Astrophysique et Planetologie, Toulouse (France); Lanza, N. [Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Mazoyer, J. [LESIA, Observatoire de Paris, Meudon (France); Melikechi, N. [Delaware State University, Dover, DE (United States); Meslin, P.-Y. [Institut de Recherche en Astrophysique et Planetologie, Toulouse (France); Newsom, H. [University of New Mexico, Albuquerque, NM (United States); and others

2013-04-01

The ChemCam instrument package on the Mars Science Laboratory rover, Curiosity, is the first planetary science instrument to employ laser-induced breakdown spectroscopy (LIBS) to determine the compositions of geological samples on another planet. Pre-processing of the spectra involves subtracting the ambient light background, removing noise, removing the electron continuum, calibrating for the wavelength, correcting for the variable distance to the target, and applying a wavelength-dependent correction for the instrument response. Further processing of the data uses multivariate and univariate comparisons with a LIBS spectral library developed prior to launch as well as comparisons with several on-board standards post-landing. The level-2 data products include semi-quantitative abundances derived from partial least squares regression. A LIBS spectral library was developed using 69 rock standards in the form of pressed powder disks, glasses, and ceramics to minimize heterogeneity on the scale of the observation (350–550 μm dia.). The standards covered typical compositional ranges of igneous materials and also included sulfates, carbonates, and phyllosilicates. The provenance and elemental and mineralogical compositions of these standards are described. Spectral characteristics of this data set are presented, including the size distribution and integrated irradiances of the plasmas, and a proxy for plasma temperature as a function of distance from the instrument. Two laboratory-based clones of ChemCam reside in Los Alamos and Toulouse for the purpose of adding new spectra to the database as the need arises. Sensitivity to differences in wavelength correlation to spectral channels and spectral resolution has been investigated, indicating that spectral registration needs to be within half a pixel and resolution needs to match within 1.5 to 2.6 pixels. Absolute errors are tabulated for derived compositions of each major element in each standard using PLS regression

Improvements to the WRF-Chem 3.5.1 model for quasi-hemispheric simulations of aerosols and ozone in the Arctic

Science.gov (United States)

Marelle, Louis; Raut, Jean-Christophe; Law, Kathy S.; Berg, Larry K.; Fast, Jerome D.; Easter, Richard C.; Shrivastava, Manish; Thomas, Jennie L.

2017-10-01

In this study, the WRF-Chem regional model is updated to improve simulated short-lived pollutants (e.g., aerosols, ozone) in the Arctic. Specifically, we include in WRF-Chem 3.5.1 (with SAPRC-99 gas-phase chemistry and MOSAIC aerosols) (1) a correction to the sedimentation of aerosols, (2) dimethyl sulfide (DMS) oceanic emissions and gas-phase chemistry, (3) an improved representation of the dry deposition of trace gases over seasonal snow, and (4) an UV-albedo dependence on snow and ice cover for photolysis calculations. We also (5) correct the representation of surface temperatures over melting ice in the Noah Land Surface Model and (6) couple and further test the recent KF-CuP (Kain-Fritsch + Cumulus Potential) cumulus parameterization that includes the effect of cumulus clouds on aerosols and trace gases. The updated model is used to perform quasi-hemispheric simulations of aerosols and ozone, which are evaluated against surface measurements of black carbon (BC), sulfate, and ozone as well as airborne measurements of BC in the Arctic. The updated model shows significant improvements in terms of seasonal aerosol cycles at the surface and root mean square errors (RMSEs) for surface ozone, aerosols, and BC aloft, compared to the base version of the model and to previous large-scale evaluations of WRF-Chem in the Arctic. These improvements are mostly due to the inclusion of cumulus effects on aerosols and trace gases in KF-CuP (improved RMSE for surface BC and BC profiles, surface sulfate, and surface ozone), the improved surface temperatures over sea ice (surface ozone, BC, and sulfate), and the updated trace gas deposition and UV albedo over snow and ice (improved RMSE and correlation for surface ozone). DMS emissions and chemistry improve surface sulfate at all Arctic sites except Zeppelin, and correcting aerosol sedimentation has little influence on aerosols except in the upper troposphere.

Ensaios clínicos toxicológicos, fase I, de um fitoterápico composto (Schinus terebinthifolius Raddi, Plectranthus amboinicus Lour e Eucalyptus globulus Labill

Directory of Open Access Journals (Sweden)

Patrícia Trindade C. Paulo

Full Text Available Neste estudo, foram realizados ensaios clínicos toxicológicos, fase I, do produto fitoterápico composto pelas plantas medicinais Schinus terebinthifolius Raddi, Plectranthus amboinicus Lour e Eucalyptus globulus Labill. O estudo foi realizado no Hospital Universitário Lauro Wanderley/UFPB/PB e, para isto, foram selecionados 28 voluntários sadios, sendo 14 homens e 14 mulheres que ingeriram por via oral, ininterruptamente durante 8 semanas, 15 mL do produto, três vezes ao dia; e no 3º e 7º dia, 3ª e 6ª semanas e 24 h após a 8ª semana, foram feitas avaliações clínicas e laboratoriais para análise da toxicidade aguda e crônica. Os resultados obtidos demonstraram que os pacientes não apresentaram alterações clínicas, laboratoriais e reações adversas significantes, apenas pequenas alterações foram detectadas no sangue através da aspartato transaminase (AST e fosfatase alcalina no grupo feminino para um p < 0,05; no entanto, estes valores determinados permaneceram dentro dos valores de normalidade para indivíduos adultos. Conclui-se que estes dados, em complementação àqueles obtidos com os estudos pré-clínicos, confirmam a baixa toxicidade do produto fitoterápico.

Validating the WRF-Chem model for wind energy applications using High Resolution Doppler Lidar data from a Utah 2012 field campaign

Science.gov (United States)

Mitchell, M. J.; Pichugina, Y. L.; Banta, R. M.

2015-12-01

Models are important tools for assessing potential of wind energy sites, but the accuracy of these projections has not been properly validated. In this study, High Resolution Doppler Lidar (HRDL) data obtained with high temporal and spatial resolution at heights of modern turbine rotors were compared to output from the WRF-chem model in order to help improve the performance of the model in producing accurate wind forecasts for the industry. HRDL data were collected from January 23-March 1, 2012 during the Uintah Basin Winter Ozone Study (UBWOS) field campaign. A model validation method was based on the qualitative comparison of the wind field images, time-series analysis and statistical analysis of the observed and modeled wind speed and direction, both for case studies and for the whole experiment. To compare the WRF-chem model output to the HRDL observations, the model heights and forecast times were interpolated to match the observed times and heights. Then, time-height cross-sections of the HRDL and WRF-Chem wind speed and directions were plotted to select case studies. Cross-sections of the differences between the observed and forecasted wind speed and directions were also plotted to visually analyze the model performance in different wind flow conditions. A statistical analysis includes the calculation of vertical profiles and time series of bias, correlation coefficient, root mean squared error, and coefficient of determination between two datasets. The results from this analysis reveals where and when the model typically struggles in forecasting winds at heights of modern turbine rotors so that in the future the model can be improved for the industry.

The toxicity of silver to soil organisms exposed to silver nanoparticles and silver nitrate in biosolids-amended field soil.

Science.gov (United States)

Jesmer, Alexander H; Velicogna, Jessica R; Schwertfeger, Dina M; Scroggins, Richard P; Princz, Juliska I

2017-10-01

The use of engineered silver nanoparticles (AgNPs) is widespread, with expected release to the terrestrial environment through the application of biosolids onto agricultural lands. The toxicity of AgNPs and silver nitrate (AgNO 3 ; as ionic Ag + ) to plant (Elymus lanceolatus and Trifolium pratense) and soil invertebrate (Eisenia andrei and Folsomia candida) species was assessed using Ag-amended biosolids applied to a natural sandy loam soil. Bioavailable Ag + in soil samples was estimated using an ion-exchange technique applied to KNO 3 soil extracts, whereas exposure to dispersible AgNPs was verified by single-particle inductively coupled plasma-mass spectrometry and transmission electron microscopy-energy dispersive X-ray spectroscopy analysis. Greater toxicity to plant growth and earthworm reproduction was observed in AgNP exposures relative to those of AgNO 3 , whereas no difference in toxicity was observed for F. candida reproduction. Transformation products in the AgNP-biosolids exposures resulted in larger pools of extractable Ag + than those from AgNO 3 -biosolids exposures, at similar total Ag soil concentrations. The results of the present study reveal intrinsic differences in the behavior and bioavailability of the 2 different forms of Ag within the biosolids-soils pathway. The present study demonstrates how analytical methods that target biologically relevant fractions can be used to advance the understanding of AgNP behavior and toxicity in terrestrial environments. Environ Toxicol Chem 2017;36:2756-2765. © 2017 Crown in the Right of Canada. Published Wiley Periodicals Inc., on behalf of SETAC. © 2017 Crown in the Right of Canada. Published Wiley Periodicals Inc., on behalf of SETAC.

The ChemScreen project to design a pragmatic alternative approach to predict reproductive toxicity of chemicals

DEFF Research Database (Denmark)

van der Burg, Bart; Wedebye, Eva Bay; Dietrich, Daniel R.

2015-01-01

to validate the test panel using mechanistic approaches. We are actively engaged in promoting regulatory acceptance of the tools developed as an essential step towards practical application, including case studies for read-across purposes. With this approach, a significant saving in animal use and associated......There is a great need for rapid testing strategies for reproductive toxicity testing, avoiding animal use. The EU Framework program 7 project ChemScreen aimed to fill this gap in a pragmatic manner preferably using validated existing tools and place them in an innovative alternative testing...

ChemCam Passive Sky Spectroscopy at Gale Crater, Mars: Interannual Variability in Dust Aerosol Particle Size, Missing Water Vapor, and the Molecular Oxygen Problem

Science.gov (United States)

McConnochie, T. H.; Smith, M. D.; Wolff, M. J.; Bender, S. C.; Lemmon, M. T.; Wiens, R. C.; Maurice, S.; Gasnault, O.; Lasue, J.; Meslin, P. Y.; Harri, A. M.; Genzer, M.; Kemppinen, O.; Martinez, G.; DeFlores, L. P.; Blaney, D. L.; Johnson, J. R.; Bell, J. F., III; Trainer, M. G.; Lefèvre, F.; Atreya, S. K.; Mahaffy, P. R.; Wong, M. H.; Franz, H. B.; Guzewich, S.; Villanueva, G. L.; Khayat, A. S.

2017-12-01

The Mars Science Laboratory's (MSL) ChemCam spectrometer measures atmospheric aerosol properties and gas abundances by operating in passive mode and observing scattered sky light at two different elevation angles. We have previously [e. g. 1, 2] presented the methodology and results of these ChemCam Passive Sky observations. Here we will focus on three of the more surprising results that we have obtained: (1) depletion of the column water vapor at Gale Crater relative to that of the surrounding region combined with a strong enhancement of the local column water vapor relative to pre-dawn in-situ measurements, (2) an interannual change in the effective particle size of dust aerosol during the aphelion season, and (3) apparent seasonal and interannual variability in molecular oxygen that differs significantly from the expected behavior of a non-condensable trace gas and differs significantly from global climate model expectations. The ChemCam passive sky water vapor measurements are quite robust but their interpretation depends on the details of measurements as well as on the types of water vapor vertical distributions that can be produced by climate models. We have a high degree of confidence in the dust particle size changes but since aerosol results in general are subject to a variety of potential systematic effects our particle size results would benefit from confirmation by other techniques [c.f. 3]. For the ChemCam passive sky molecular oxygen results we are still working to constrain the uncertainties well enough to confirm the observed surprising behavior, motivated by similarly surprising atmospheric molecular oxygen variability observed by MSL's Sample Analysis at Mars (SAM) instrument [4]. REFERENCES: [1] McConnochie, et al. (2017), Icarus (submitted). [2] McConnochie, et al. (2017), abstract # 3201, The 6th International Workshop on the Mars Atmosphere: Granada, Spain. [3] Vicente-Retortillo et al. (2017), GRL, 44. [4] Trainer et al. (2017), 2017 AGU Fall

Qualidade físico-química e toxicológica de farinha obtida do eixo central de jaca

Directory of Open Access Journals (Sweden)

Hyago Costa Sousa

2016-11-01

Full Text Available A produção de farinha do eixo central de jaca se apresenta como uma alternativa viável para o aproveitamento dessa parte do fruto e sua utilização na indústria. O projeto foi desenvolvido no Centro de Ciências Humanas, Sociais e Agrárias, Bananeiras-PB pertencente a Universidade Federal da Paraíba. Os frutos foram adquiridos no pomar do CCHSA. As farinhas foram obtidas a partir da secagem do eixo central em quatro diferentes temperaturas 50, 60, 70 e 80 °C. Foi determinada a potencialidade toxicológica frente Artemia Salina do eixo central e de suas respectivas farinhas bem como sua caracterização físico-química. O eixo central de jaca não apresentou toxicidade assim como as farinhas obtidas a 50, 60 e 70 °C. A farinha do eixo central obtida a temperatura de 50 °C apresentou os melhores resultados nas análises físico-químicas.Physicochemical and toxicological quality of flour obtained from the central axis of jackfruitAbstract The production of flour from the central axis of jackfruit is presented as a viable alternative to the use of this part of the fruit and its use in industry. The project was developed in the Humanities Center, Social and Agricultural, Bananeiras-PB belonging to the Federal University of Paraíba. The fruits were purchased in CCHSA orchard. The flour were obtained by drying the central axis at four different temperatures 50, 60, 70 and 80 ° C. It was determined the toxicological potential front Artemia Salina central axis and their respective flours and their physicochemical characterization. The central axis of jackfruit showed no toxicity as well as the flour obtained at 50, 60 and 70 ° C. The flour the central axis obtained at 50 ° C showed the best results in physicochemical analyzes.

Development of a Relative Source Contribution Factor for Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)

Science.gov (United States)

2009-09-01

Japanese millet , perennial ryegrass, carrot shoot, spinach seeds, etc.) (Cataldo et al., 1990; Checkai and Simini, 1996; Price et al., 1997; Fellows et al...environmental effects and screening values. Rev Environ Contam Toxicol 161:1-156. Todd, Q., Finger , F., Tuner, R., Morley, D. 1989. Delivery

Dust modeling over East Asia during the summer of 2010 using the WRF-Chem model

Science.gov (United States)

Zhang, B.; Huang, J.; Chen, S.

2017-12-01

An intense summer dust storm over East Asia during June 24-27, 2010, was systematically analyzed using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and a variety of in situ measurements and satellite retrievals. The results showed that the WRF-Chem model captured the spatial and temporal distributions of meteorological factors and dust aerosols over East Asia. This summer dust storm was initiated by the approach of a transverse trough in the northwestern Xinjiang. Because of the passage of the cutoff-low, a large amount of cold air was transported southward and further enhanced in the narrow valleys of the Altai and Tianshan Mountains, which resulted in higher wind speeds and huge dust emissions over the Taklimakan Desert (TD). Dust emission fluxes over the TD were as high as 54 μg m-2 s-1 on June 25th. The dust aerosols from the TD then swept across Inner Mongolia, Ningxia and Mongolia, and some were also transported eastward to Beijing, Tianjin, the Hebei region, and even South Korea and Japan. The simulations further showed that summer dust over East Asia exerts an important influence on the radiation budget in the Earth-atmosphere system. Dust heat the atmosphere at a maximum heating rate of 0.14 k day-1, effectively changing the vertical stability of the atmosphere and affecting climate change at regional and even global scales. The dust event-averaged direct radiative forcing induced by dust particles over the TD at all-sky was -6.0, -16.8 and 10.8 W m-2 at the top of the atmosphere, the surface, and in the atmosphere, respectively.

Survey on the presence of non-dioxine-like PCBs (NDL-PCBs) in loggerhead turtles (Caretta caretta) stranded in south Mediterranean coasts (Sicily, Southern Italy).

Science.gov (United States)

Cammilleri, Gaetano; Calvaruso, Enza; Pantano, Licia; Cascio, Giovanni Lo; Randisi, Barbara; Macaluso, Andrea; Vazzana, Mirella; Caracappa, Giulia; Giangrosso, Giuseppe; Vella, Antonio; Ferrantelli, Vincenzo

2017-11-01

A total of 71 loggerhead turtles (Caretta caretta) stranded along the coasts of Sicily (Southern Italy) were examined for non-dioxine like polychlorinated biphenyl (NDL-PCB) levels in muscle and adipose tissue by a gas chromatography-mass spectrometry/mass spectrometry (GC-MS/MS) method. The results revealed 6 high-indicator congener (∑ 6 PCB IND ) levels in 45% of the loggerhead turtles examined, with mean values of 980.39 ± 2508.39 ng/g wet weight in adipose tissue and 102.53 ± 238.58 ng/g wet weight in muscle tissue. The hexachloro and heptachloro PCB congeners were the most abundant in both the sample types. The highest NDL-PCB levels were reached in an adipose tissue sample of a loggerhead turtle of 80 kg stranded along the coasts of Termini Imerese (14 183.85 ng/g wet wt). No significant correlation was found between modified Fulton's K values of the loggerhead turtles and PCB contents (S = 47 151, p > 0.05). Furthermore, no significant differences were found between sexes (W = 365, p >  0.05). The PCB levels found in the present study were much higher than those found in the literature. The present study is the first report on the existence of NDL-PCBs in loggerhead turtles stranded in Sicilian coasts confirming C. caretta as a valuable indicator of contaminant exposure in the marine environment because of their specific biological and ecological characteristics. Environ Toxicol Chem 2017;36:2997-3002. © 2017 SETAC. © 2017 SETAC.

Exploring REACH as a potential data source for characterizing ecotoxicity in life cycle assessment.

Science.gov (United States)

Müller, Nienke; de Zwart, Dick; Hauschild, Michael; Kijko, Gaël; Fantke, Peter

2017-02-01

Toxicity models in life cycle impact assessment (LCIA) currently only characterize a small fraction of marketed substances, mostly because of limitations in the underlying ecotoxicity data. One approach to improve the current data situation in LCIA is to identify new data sources, such as the European Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH) database. The present study explored REACH as a potential data source for LCIA based on matching reported ecotoxicity data for substances that are currently also included in the United Nations Environment Programme/Society for Environmental Toxicology and Chemistry (UNEP/SETAC) scientific consensus model USEtox for characterizing toxicity impacts. Data are evaluated with respect to number of data points, reported reliability, and test duration, and are compared with data listed in USEtox at the level of hazardous concentration for 50% of the covered species per substance. The results emphasize differences between data available via REACH and in USEtox. The comparison of ecotoxicity data from REACH and USEtox shows potential for using REACH ecotoxicity data in LCIA toxicity characterization, but also highlights issues related to compliance of submitted data with REACH requirements as well as different assumptions underlying regulatory risk assessment under REACH versus data needed for LCIA. Thus, further research is required to address data quality, pre-processing, and applicability, before considering data submitted under REACH as a data source for use in LCIA, and also to explore additionally available data sources, published studies, and reports. Environ Toxicol Chem 2017;36:492-500. © 2016 SETAC. © 2016 SETAC.

Investigation of a new passive sampler for the detection of munitions compounds in marine and freshwater systems.

Science.gov (United States)

Warren, Joseph K; Vlahos, Penny; Smith, Richard; Tobias, Craig

2018-07-01

Over the last century, unexploded ordnances have been disposed of in marine shelf systems because of a lack of cost-effective alternatives. Underwater unexploded ordnances have the potential to leak 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitro-1,3,5-triazine (RDX), commonly used chemical munitions, and contaminate local waters, biota, and sediments. The rate at which this contamination occurs in the environment is relatively unknown, and the cost- and time-prohibitive nature of sampling across sites makes mapping difficult. In the present study we assessed the efficacy of ethylene-vinyl acetate (EVA) for sampling relatively soluble munitions compounds over a range of environmental conditions (i.e., changes in temperature and salinity) and optimized the composition of the passive sampling polymer. The EVA sampler was able to successfully detect ambient concentrations of lingering munitions compounds from field sites containing unexploded ordnances. The sampler affinity for the munitions in terms of an EVA-water partition coefficient was greater than the standard octanol water values for each target compound. Partitioning of compounds onto EVA over the natural ranges of salinity did not change significantly, although uptake varied consistently and predictably with temperature. Increasing the vinyl acetate to ethylene ratio of the polymer corresponded to an increase in uptake capacity, consistent with enhanced dipole-dipole interactions between the munitions and the polymer. This sampler provides a cost-effective means to map and track leakage of unexploded ordnances both spatially and temporally. Environ Toxicol Chem 2018;37:1990-1997. © 2018 SETAC. © 2018 SETAC.

Effect of decabromodiphenyl ether (BDE-209) on a soil-biota system: Role of earthworms and ryegrass.

Science.gov (United States)

Feng, Mingbao; He, Qun; Shi, Jiaqi; Qin, Li; Zhang, Xuesheng; Sun, Ping; Wang, Zunyao

2016-06-01

In the present study, the toxic effect of decabromodiphenyl ether (BDE-209), an important brominated fire retardant, on soil was evaluated by amending with different concentrations (0 mg/kg, 1 mg/kg, 10 mg/kg, and 500 mg/kg dry wt) for 40 d. The activities of 3 soil enzymes (urease, catalase, and alkaline phosphatase) were measured as the principal assessment endpoints. Meanwhile, the effects of natural environmental factors, such as light conditions and soil biota, on BDE-209 intoxication were studied. For the latter, 30 earthworms (Metaphire guillelmi) with fully matured clitella or ryegrass (Lolium perenne) with fully matured leaves were exposed in soil amended with BDE-209. The activities of the soil enzymes were adversely affected by BDE-209, especially for the high-concentration treatments, with greater adverse effects in the dark than in the light. The presence of earthworms reduced toxicity to BDE-209, whereas ryegrass did not. The calculated integrated biomarker response index, which provides a general indicator of the health status of test species by combining different biomarker signals, further validated these findings. Moreover, the antioxidant status (oxidant-antioxidant balance) of these 2 biota was assessed. Results indicated that BDE-209 significantly affected the activities of antioxidant enzymes (superoxide dismutase and catalase) and enhanced the levels of malondialdehyde in both species. The present study may facilitate a better understanding of the toxicity of BDE-209 toward the soil environment. Environ Toxicol Chem 2016;35:1349-1357. © 2015 SETAC. © 2015 SETAC.

Toward improved analysis of concentration data: Embracing nondetects.

Science.gov (United States)

Shoari, Niloofar; Dubé, Jean-Sébastien

2018-03-01

Various statistical tests on concentration data serve to support decision-making regarding characterization and monitoring of contaminated media, assessing exposure to a chemical, and quantifying the associated risks. However, the routine statistical protocols cannot be directly applied because of challenges arising from nondetects or left-censored observations, which are concentration measurements below the detection limit of measuring instruments. Despite the existence of techniques based on survival analysis that can adjust for nondetects, these are seldom taken into account properly. A comprehensive review of the literature showed that managing policies regarding analysis of censored data do not always agree and that guidance from regulatory agencies may be outdated. Therefore, researchers and practitioners commonly resort to the most convenient way of tackling the censored data problem by substituting nondetects with arbitrary constants prior to data analysis, although this is generally regarded as a bias-prone approach. Hoping to improve the interpretation of concentration data, the present article aims to familiarize researchers in different disciplines with the significance of left-censored observations and provides theoretical and computational recommendations (under both frequentist and Bayesian frameworks) for adequate analysis of censored data. In particular, the present article synthesizes key findings from previous research with respect to 3 noteworthy aspects of inferential statistics: estimation of descriptive statistics, hypothesis testing, and regression analysis. Environ Toxicol Chem 2018;37:643-656. © 2017 SETAC. © 2017 SETAC.

Effect of glyphosate acid on biochemical markers of periphyton exposed in outdoor mesocosms in the presence and absence of the mussel Limnoperna fortunei.

Science.gov (United States)

Iummato, María Mercedes; Pizarro, Haydée; Cataldo, Daniel; Di Fiori, Eugenia; Dos Santos Afonso, María; Del Carmen Ríos de Molina, María; Juárez, Ángela Beatriz

2017-07-01

Glyphosate is currently the most widely used herbicide in agricultural production. It generally enters aquatic ecosystems through surface water runoff and aerial drift. We evaluated the effect of glyphosate acid on biochemical parameters of periphyton exposed to concentrations of 1, 3, and 6 mg/L in outdoor mesocosms in the presence and absence of the mussel Limnoperna fortunei. Periphyton ash-free dry weight, chlorophyll a content, carotene/chlorophyll a ratio, lipid peroxidation levels, and superoxide dismutase and catalase activities were determined at days 0, 1, 7, 14, and 26 of the experimental period. Ash-free dry weight was similar between control and glyphosate-treated periphyton in the absence of L. fortunei. The latter had significantly lower carotene to chlorophyll a ratios and enzyme activities, and higher lipid peroxidation levels and chlorophyll a content than the former. These results show an adverse effect of glyphosate on the metabolism of periphyton community organisms, possibly inducing oxidative stress. On the contrary, no differences were observed in any of these variables between control and glyphosate-treated periphyton in the presence of L. fortunei. Mussels probably attenuated the herbicide effects by contributing to glyphosate dissipation. The results also demonstrate that biochemical markers provide useful information that may warn of herbicide impact on periphyton communities. Environ Toxicol Chem 2017;36:1775-1784. © 2016 SETAC. © 2017 SETAC.

Resilience in ecotoxicology: Toward a multiple equilibrium concept.

Science.gov (United States)

Bundschuh, Mirco; Schulz, Ralf; Schäfer, Ralf B; Allen, Craig R; Angeler, David G

2017-10-01

The term resilience describes stress-response patterns across scientific disciplines. In ecology, advances have been made to clearly define resilience based on underlying mechanistic assumptions. Engineering resilience (rebound) is used to describe the ability of organisms to recover from adverse conditions (disturbances), which is termed the rate of recovery. By contrast, the ecological resilience definition considers a systemic change, that is, when ecosystems reorganize into a new regime following disturbance. Under this new regime, structural and functional aspects change considerably relative to the previous regime, without recovery. In this context, resilience is an emergent property of complex systems. In the present study, we argue that both definitions and uses are appropriate in ecotoxicology, and although the differences are subtle, the implications and uses are profoundly different. We discuss resilience concepts in ecotoxicology, where the prevailing view of resilience is engineering resilience from chemical stress. Ecological resilience may also be useful for describing systemic ecological changes because of chemical stress. We present quantitative methods that allow ecotoxicologists and risk managers to assess whether an ecosystem faces an impending regime shift or whether it has already undergone such a shift. We contend that engineering and ecological resilience help to distinguish ecotoxicological responses to chemical stressors mechanistically and thus have implications for theory, policy, and application. Environ Toxicol Chem 2017;36:2574-2580. © 2017 SETAC. © 2017 SETAC.

A comparative approach using ecotoxicological methods from single-species bioassays to model ecosystems.

Science.gov (United States)

Haegerbaeumer, Arne; Höss, Sebastian; Ristau, Kai; Claus, Evelyn; Möhlenkamp, Christel; Heininger, Peter; Traunspurger, Walter

2016-12-01

Soft sediments are often hotspots of chemical contamination, and a thorough ecotoxicological assessment of this habitat can help to identify the causes of stress and to improve the health of the respective ecosystems. As an important component of the ecologically relevant meiobenthic fauna, nematodes can be used for sediment assessments, with various assay tools ranging from single-species toxicity tests to field studies. In the present study, microcosms containing sediment were used to investigate direct and indirect effects of zinc on natural nematode assemblages, and acute community toxicity tests considering only direct toxicity were conducted. The responses of the various freshwater nematode species in both approaches were compared with those of Caenorhabditis elegans, determined in standardized tests (ISO 10872). At a median lethal concentration (LC50) of 20 mg Zn/L, C. elegans represented the median susceptibility of 15 examined nematode species examined in the acute community toxicity tests. In the microcosms, Zn affected the nematodes dose-dependently, with changes in species composition first detected at 13 mg Zn/kg to 19 mg Zn/kg sediment dry weight. The observed species sensitivities in the microcosms corresponded better to field observations than to the results of the acute community toxicity tests. Environ Toxicol Chem 2016;35:2987-2997. © 2016 SETAC. © 2016 SETAC.

Photoinduced toxicity of three polycyclic aromatic hydrocarbons (fluoranthene, pyrene, and naphthalene) to the duckweed Lemna gibba L. G-3

International Nuclear Information System (INIS)

Ren, L.; Huang, X.D.; McConkey, B.J.; Dixon, D.G.; Greenberg, B.M.

1994-01-01

The authors recently demonstrated that light dramatically enhances the hazards of three polycyclic aromatic hydrocarbons (PAHs), anthracene, phenanthrene, and benzo[a]pyrene, to the duckweed Lemna gibba L. G-3 (X.-D. Huang, D. G. Dixon, and B. M. Greenberg, 1993, Environ. Toxicol. Chem., 12, 1067-1077). To extend this research, growth and chlorosis were used as end points to assess the photoinduced toxicity of three additional PAHs, fluoranthene, pyrene, and naphthalene, to L. gibba in the presence of simulated solar radiation (a light source with a UV-B: UV-A:visible light ratio equivalent to that of sunlight). The phytotoxicity of these three PAHs was photoactivated, with ultraviolet radiation being the only spectral region that enhanced the harmful effects of the chemicals. Dose-response curves based on chemical concentration and light intensity revealed that the order of phytotoxic strength was fluoranthene > pyrene > naphthalene. To explore whether photomodification (in addition to photosensitization) of fluoranthene, pyrene, and naphthalene could contribute to photoinduced toxicity, the chemicals were irradiated prior to (as opposed to simultaneously with) application to the plans. The rates of photomodification of the three PAHs were rapid enough for the photooxidized compounds to contribute to toxicity, and the photomodified PAHs were more toxic than the parent compounds. As well, toxicity could be correlated to photomodification; impacts increased in parallel with the extent of photomodification

Recovery of aquatic insect-mediated methylmercury flux from ponds following drying disturbance.

Science.gov (United States)

Chumchal, Matthew M; Drenner, Ray W; Greenhill, Frank M; Kennedy, James H; Courville, Ashlyn E; Gober, Charlie A A; Lossau, Luke O

2017-08-01

Small ponds exist across a permanence gradient, and pond permanence is hypothesized to be a primary determinant of insect community structure and insect-mediated methylmercury (MeHg) flux from ponds to the surrounding terrestrial landscape. The present study describes the first experiment examining the recovery of insect-mediated MeHg flux following a drying disturbance that converted permanent ponds with insectivorous fish to semipermanent ponds without fish. Floating emergence traps were used to collect emergent insects for 10 wk in the spring and summer from 5 ponds with fish (permanent) and 5 ponds that were drained to remove fish, dried, and refilled with water (semipermanent). During the 73-d period after semipermanent ponds were refilled, total MeHg flux from semipermanent ponds was not significantly different than total MeHg flux from permanent ponds, indicating that insect-mediated MeHg flux had rapidly recovered in semipermanent ponds following the drying disturbance. Methylmercury fluxes from dragonflies (Odonata: Anisoptera) and phantom midges (Diptera: Chaoboridae) were significantly greater from newly refilled semipermanent ponds than permanent ponds, but the MeHg fluxes from the other 8 emergent insect taxa did not differ between treatments. The present study demonstrates the impact of drying disturbance and the effect of community structure on the cross-system transport of contaminants from aquatic to terrestrial ecosystems. Environ Toxicol Chem 2017;36:1986-1990. © 2017 SETAC. © 2017 SETAC.

Combining exposure and effect modeling into an integrated probabilistic environmental risk assessment for nanoparticles.

Science.gov (United States)

Jacobs, Rianne; Meesters, Johannes A J; Ter Braak, Cajo J F; van de Meent, Dik; van der Voet, Hilko

2016-12-01

There is a growing need for good environmental risk assessment of engineered nanoparticles (ENPs). Environmental risk assessment of ENPs has been hampered by lack of data and knowledge about ENPs, their environmental fate, and their toxicity. This leads to uncertainty in the risk assessment. To deal with uncertainty in the risk assessment effectively, probabilistic methods are advantageous. In the present study, the authors developed a method to model both the variability and the uncertainty in environmental risk assessment of ENPs. This method is based on the concentration ratio and the ratio of the exposure concentration to the critical effect concentration, both considered to be random. In this method, variability and uncertainty are modeled separately so as to allow the user to see which part of the total variation in the concentration ratio is attributable to uncertainty and which part is attributable to variability. The authors illustrate the use of the method with a simplified aquatic risk assessment of nano-titanium dioxide. The authors' method allows a more transparent risk assessment and can also direct further environmental and toxicological research to the areas in which it is most needed. Environ Toxicol Chem 2016;35:2958-2967. © 2016 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC. © 2016 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

Evaluation of the phototoxicity of unsubstituted and alkylated polycyclic aromatic hydrocarbons to mysid shrimp (Americamysis bahia): Validation of predictive models.

Science.gov (United States)

Finch, Bryson E; Marzooghi, Solmaz; Di Toro, Dominic M; Stubblefield, William A

2017-08-01

Crude oils are composed of an assortment of hydrocarbons, some of which are polycyclic aromatic hydrocarbons (PAHs). Polycyclic aromatic hydrocarbons are of particular interest due to their narcotic and potential phototoxic effects. Several studies have examined the phototoxicity of individual PAHs and fresh and weathered crude oils, and several models have been developed to predict PAH toxicity. Fingerprint analyses of oils have shown that PAHs in crude oils are predominantly alkylated. However, current models for estimating PAH phototoxicity assume toxic equivalence between unsubstituted (i.e., parent) and alkyl-substituted compounds. This approach may be incorrect if substantial differences in toxic potency exist between unsubstituted and substituted PAHs. The objective of the present study was to examine the narcotic and photo-enhanced toxicity of commercially available unsubstituted and alkylated PAHs to mysid shrimp (Americamysis bahia). Data were used to validate predictive models of phototoxicity based on the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gap approach and to develop relative effect potencies. Results demonstrated that photo-enhanced toxicity increased with increasing methylation and that phototoxic PAH potencies vary significantly among unsubstituted compounds. Overall, predictive models based on the HOMO-LUMO gap were relatively accurate in predicting phototoxicity for unsubstituted PAHs but are limited to qualitative assessments. Environ Toxicol Chem 2017;36:2043-2049. © 2017 SETAC. © 2017 SETAC.

Salinity impacts on water solubility and n-octanol/water partition coefficients of selected pesticides and oil constituents.

Science.gov (United States)

Saranjampour, Parichehr; Vebrosky, Emily N; Armbrust, Kevin L

2017-09-01

Salinity has been reported to influence the water solubility of organic chemicals entering marine ecosystems. However, limited data are available on salinity impacts for chemicals potentially entering seawater. Impacts on water solubility would correspondingly impact chemical sorption as well as overall bioavailability and exposure estimates used in the regulatory assessment. The pesticides atrazine, fipronil, bifenthrin, and cypermethrin, as well as the crude oil constituent dibenzothiophene together with 3 of its alkyl derivatives, all have different polarities and were selected as model compounds to demonstrate the impact of salinity on their solubility and partitioning behavior. The n-octanol/water partition coefficient (K OW ) was measured in both distilled-deionized water and artificial seawater (3.2%). All compounds had diminished solubility and increased K OW values in artificial seawater compared with distilled-deionized water. A linear correlation curve estimated salinity may increase the log K OW value by 2.6%/1 log unit increase in distilled water (R 2  = 0.97). Salinity appears to generally decrease the water solubility and increase the partitioning potential. Environmental fate estimates based on these parameters indicate elevated chemical sorption to sediment, overall bioavailability, and toxicity in artificial seawater. These dramatic differences suggest that salinity should be taken into account when exposure estimates are made for marine organisms. Environ Toxicol Chem 2017;36:2274-2280. © 2017 SETAC. © 2017 SETAC.

Modeling individual movement decisions of brown hare (Lepus europaeus) as a key concept for realistic spatial behavior and exposure: A population model for landscape-level risk assessment.

Science.gov (United States)

Kleinmann, Joachim U; Wang, Magnus

2017-09-01

Spatial behavior is of crucial importance for the risk assessment of pesticides and for the assessment of effects of agricultural practice or multiple stressors, because it determines field use, exposition, and recovery. Recently, population models have increasingly been used to understand the mechanisms driving risk and recovery or to conduct landscape-level risk assessments. To include spatial behavior appropriately in population models for use in risk assessments, a new method, "probabilistic walk," was developed, which simulates the detailed daily movement of individuals by taking into account food resources, vegetation cover, and the presence of conspecifics. At each movement step, animals decide where to move next based on probabilities being determined from this information. The model was parameterized to simulate populations of brown hares (Lepus europaeus). A detailed validation of the model demonstrated that it can realistically reproduce various natural patterns of brown hare ecology and behavior. Simulated proportions of time animals spent in fields (PT values) were also comparable to field observations. It is shown that these important parameters for the risk assessment may, however, vary in different landscapes. The results demonstrate the value of using population models to reduce uncertainties in risk assessment and to better understand which factors determine risk in a landscape context. Environ Toxicol Chem 2017;36:2299-2307. © 2017 SETAC. © 2017 SETAC.

Mercury contamination in bats from the central United States.

Science.gov (United States)

Korstian, Jennifer M; Chumchal, Matthew M; Bennett, Victoria J; Hale, Amanda M

2018-01-01

Mercury (Hg) is a highly toxic metal that has detrimental effects on wildlife. We surveyed Hg concentrations in 10 species of bats collected at wind farms in the central United States and found contamination in all species. Mercury concentration in fur was highly variable both within and between species (range: 1.08-10.52 µg/g). Despite the distance between sites (up to 1200 km), only 2 of the 5 species sampled at multiple locations had fur Hg concentrations that differed between sites. Mercury concentrations observed in the present study all fell within the previously reported ranges for bats collected from the northeastern United States and Canada, although many of the bats we sampled had lower maximum Hg concentrations. Juvenile bats had lower concentrations of Hg in fur compared with adult bats, and we found no significant effect of sex on Hg concentrations in fur. For a subset of 2 species, we also measured Hg concentration in muscle tissue; concentrations were much higher in fur than in muscle, and Hg concentrations in the 2 tissue types were weakly correlated. Abundant wind farms and ongoing postconstruction fatality surveys offer an underutilized opportunity to obtain tissue samples that can be used to assess Hg contamination in bats. Environ Toxicol Chem 2018;37:160-165. © 2018 SETAC. © 2017 SETAC.

Tracking pyrethroid toxicity in surface water samples: Exposure dynamics and toxicity identification tools for laboratory tests with Hyalella azteca (Amphipoda).

Science.gov (United States)

Deanovic, Linda A; Stillway, Marie; Hammock, Bruce G; Fong, Stephanie; Werner, Inge

2018-02-01

Pyrethroid insecticides are commonly used in pest control and are present at toxic concentrations in surface waters of agricultural and urban areas worldwide. Monitoring is challenging as a result of their high hydrophobicity and low toxicity thresholds, which often fall below the analytical methods detection limits (MDLs). Standard daphnid bioassays used in surface water monitoring are not sensitive enough to protect more susceptible invertebrate species such as the amphipod Hyalella azteca and chemical loss during toxicity testing is of concern. In the present study, we quantified toxicity loss during storage and testing, using both natural and synthetic water, and presented a tool to enhance toxic signal strength for improved sensitivity of H. azteca toxicity tests. The average half-life during storage in low-density polyethylene (LDPE) cubitainers (Fisher Scientific) at 4 °C of 5 pyrethroids (permethrin, bifenthrin, lambda-cyhalothrin, cyfluthrin, and esfenvalerate) and one organophosphate (chlorpyrifos; used as reference) was 1.4 d, and piperonyl butoxide (PBO) proved an effective tool to potentiate toxicity. We conclude that toxicity tests on ambient water samples containing these hydrophobic insecticides are likely to underestimate toxicity present in the field, and mimic short pulse rather than continuous exposures. Where these chemicals are of concern, the addition of PBO during testing can yield valuable information on their presence or absence. Environ Toxicol Chem 2018;37:462-472. © 2017 SETAC. © 2017 SETAC.

A new method to quantify the health risks from sources of perfluoroalkyl substances, combined with positive matrix factorization and risk assessment models.

Science.gov (United States)

Xu, Jiao; Shi, Guo-Liang; Guo, Chang-Sheng; Wang, Hai-Ting; Tian, Ying-Ze; Huangfu, Yan-Qi; Zhang, Yuan; Feng, Yin-Chang; Xu, Jian

2018-01-01

A hybrid model based on the positive matrix factorization (PMF) model and the health risk assessment model for assessing risks associated with sources of perfluoroalkyl substances (PFASs) in water was established and applied at Dianchi Lake to test its applicability. The new method contains 2 stages: 1) the sources of PFASs were apportioned by the PMF model and 2) the contribution of health risks from each source was calculated by the new hybrid model. Two factors were extracted by PMF, with factor 1 identified as aqueous fire-fighting foams source and factor 2 as fluoropolymer manufacturing and processing and perfluorooctanoic acid production source. The health risk of PFASs in the water assessed by the health risk assessment model was 9.54 × 10 -7  a -1 on average, showing no obvious adverse effects to human health. The 2 sources' risks estimated by the new hybrid model ranged from 2.95 × 10 -10 to 6.60 × 10 -6  a -1 and from 1.64 × 10 -7 to 1.62 × 10 -6  a -1 , respectively. The new hybrid model can provide useful information on the health risks of PFAS sources, which is helpful for pollution control and environmental management. Environ Toxicol Chem 2018;37:107-115. © 2017 SETAC. © 2017 SETAC.

Effect of natural organic matter on the photo-induced toxicity of titanium dioxide nanoparticles.

Science.gov (United States)

Wormington, Alexis M; Coral, Jason; Alloy, Matthew M; Delmarè, Carmen L; Mansfield, Charles M; Klaine, Stephen J; Bisesi, Joseph H; Roberts, Aaron P

2017-06-01

Nano-titanium dioxide (TiO 2 ) is the most widely used form of nanoparticles in commercial industry and comes in 2 main configurations: rutile and anatase. Rutile TiO 2 is used in ultraviolet (UV) screening applications, whereas anatase TiO 2 crystals have a surface defect that makes them photoreactive. There are numerous reports in the literature of photo-induced toxicity to aquatic organisms following coexposure to anatase nano-TiO 2 and UV. All natural freshwater contains varying amounts of natural organic matter (NOM), which can drive UV attenuation and quench reactive oxygen species (ROS) in aquatic ecosystems. The present research examined how NOM alters the photo-induced toxicity of anatase nano-TiO 2 . Daphnia magna neonates were coexposed to NOM and photoexcited anatase nano-TiO 2 for 48 h. Natural organic matter concentrations as low as 4 mg/L reduced anatase nano-TiO 2 toxicity by nearly 100%. These concentrations of NOM attenuated UV by <10% in the exposure system. However, ROS production measured using a fluorescence assay was significantly reduced in a NOM concentration--dependent manner. Taken together, these data suggest that NOM reduces anatase nano-TiO 2 toxicity via an ROS quenching mechanism and not by attenuation of UV. Environ Toxicol Chem 2017;36:1661-1666. © 2016 SETAC. © 2016 SETAC.

Development and application of the SSD approach in scientific case studies for ecological risk assessment.

Science.gov (United States)

Del Signore, Anastasia; Hendriks, A Jan; Lenders, H J Rob; Leuven, Rob S E W; Breure, A M

2016-09-01

Species sensitivity distributions (SSDs) are used in ecological risk assessment for extrapolation of the results of toxicity tests with single species to a toxicity threshold considered protective of ecosystem structure and functioning. The attention to and importance of the SSD approach has increased in scientific and regulatory communities since the 1990s. Discussion and criticism have been triggered on the concept of the approach as well as its technical aspects (e.g., distribution type, number of toxicity endpoints). Various questions remain unanswered, especially with regard to different endpoints, statistical methods, and protectiveness of threshold levels, for example. In the present literature review (covering the period 2002-2013), case studies are explored in which the SSD approach was applied, as well as how endpoint types, species choice, and data availability affect SSDs. How statistical methods may be used to construct reliable SSDs and whether the lower 5th percentile hazard concentrations (HC5s) from a generic SSD can be protective for a specific local community are also investigated. It is shown that estimated protective concentrations were determined by taxonomic groups rather than the statistical method used to construct the distribution. Based on comparisons between semifield and laboratory-based SSDs, the output from a laboratory SSD was protective of semifield communities in the majority of studies. Environ Toxicol Chem 2016;35:2149-2161. © 2016 SETAC. © 2016 SETAC.

Natural variability of biochemical biomarkers in the macro-zoobenthos: Dependence on life stage and environmental factors.

Science.gov (United States)

Scarduelli, Lucia; Giacchini, Roberto; Parenti, Paolo; Migliorati, Sonia; Di Brisco, Agnese Maria; Vighi, Marco

2017-11-01

Biomarkers are widely used in ecotoxicology as indicators of exposure to toxicants. However, their ability to provide ecologically relevant information remains controversial. One of the major problems is understanding whether the measured responses are determined by stress factors or lie within the natural variability range. In a previous work, the natural variability of enzymatic levels in invertebrates sampled in pristine rivers was proven to be relevant across both space and time. In the present study, the experimental design was improved by considering different life stages of the selected taxa and by measuring more environmental parameters. The experimental design considered sampling sites in 2 different rivers, 8 sampling dates covering the whole seasonal cycle, 4 species from 3 different taxonomic groups (Plecoptera, Perla grandis; Ephemeroptera, Baetis alpinus and Epeorus alpicula; Tricoptera, Hydropsyche pellucidula), different life stages for each species, and 4 enzymes (acetylcholinesterase, glutathione S-transferase, alkaline phosphatase, and catalase). Biomarker levels were related to environmental (physicochemical) parameters to verify any kind of dependence. Data were statistically elaborated using hierarchical multilevel Bayesian models. Natural variability was found to be relevant across both space and time. The results of the present study proved that care should be paid when interpreting biomarker results. Further research is needed to better understand the dependence of the natural variability on environmental parameters. Environ Toxicol Chem 2017;36:3158-3167. © 2017 SETAC. © 2017 SETAC.

A re-evaluation of PETROTOX for predicting acute and chronic toxicity of petroleum substances.

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Redman, Aaron D; Parkerton, Thomas F; Leon Paumen, Miriam; Butler, Josh D; Letinski, Daniel J; den Haan, Klass

2017-08-01

The PETROTOX model was developed to perform aquatic hazard assessment of petroleum substances based on substance composition. The model relies on the hydrocarbon block method, which is widely used for conducting petroleum substance risk assessments providing further justification for evaluating model performance. Previous work described this model and provided a preliminary calibration and validation using acute toxicity data for limited petroleum substance. The objective of the present study was to re-evaluate PETROTOX using expanded data covering both acute and chronic toxicity endpoints on invertebrates, algae, and fish for a wider range of petroleum substances. The results indicated that recalibration of 2 model parameters was required, namely, the algal critical target lipid body burden and the log octanol-water partition coefficient (K OW ) limit, used to account for reduced bioavailability of hydrophobic constituents. Acute predictions from the updated model were compared with observed toxicity data and found to generally be within a factor of 3 for algae and invertebrates but overestimated fish toxicity. Chronic predictions were generally within a factor of 5 of empirical data. Furthermore, PETROTOX predicted acute and chronic hazard classifications that were consistent or conservative in 93 and 84% of comparisons, respectively. The PETROTOX model is considered suitable for the purpose of characterizing petroleum substance hazard in substance classification and risk assessments. Environ Toxicol Chem 2017;36:2245-2252. © 2017 SETAC. © 2017 SETAC.

Determination of the speciation and bioavailability of samarium to Chlamydomonas reinhardtii in the presence of natural organic matter.

Science.gov (United States)

Rowell, Justine-Anne; Fillion, Marc-Alexandre; Smith, Scott; Wilkinson, Kevin J

2018-06-01

As technological interest and environmental emissions of the rare earth elements increase, it is becoming more important to assess their potential environmental impact. Samarium (Sm) is a lanthanide of intermediate molar mass that is used in numerous high-technology applications including wind turbines, solar panels, and electric vehicles. The present study relates the speciation of Sm determined in the presence of natural organic matter (NOM) to its bioavailability to the unicellular green alga Chlamydomonas reinhardtii. The free ion concentration was determined using a cation exchange resin (ion exchange technique) in dynamic mode and compared with thermodynamic modeling. Short-term biouptake experiments were performed in the presence of 4 types of NOM: Suwannee River fulvic acids, Pahokee Peat fulvic acids, Suwannee River humic acids, and a Luther Marsh dissolved organic matter isolate (90-95% humic acids). It was clearly shown that even a small amount of NOM (0.5 mg C L -1 ) resulted in a significant decrease (10 times) in the Sm internalization fluxes. Furthermore, complexation with humic acids (and the corresponding reduction in Sm bioavailability) was stronger than that with fulvic acids. The results showed that the experimentally measured (free) Sm was a better predictor of Sm internalization than either the total concentrations or the free ion concentrations obtained using thermodynamic modeling. Environ Toxicol Chem 2018;37:1623-1631. © 2018 SETAC. © 2018 SETAC.

DayCent-Chem Simulations of Ecological and Biogeochemical Processes of Eight Mountain Ecosystems in the United States

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Hartman, Melannie D.; Baron, Jill S.; Clow, David W.; Creed, Irena F.; Driscoll, Charles T.; Ewing, Holly A.; Haines, Bruce D.; Knoepp, Jennifer; Lajtha, Kate; Ojima, Dennis S.; Parton, William J.; Renfro, Jim; Robinson, R. Bruce; Van Miegroet, Helga; Weathers, Kathleen C.; Williams, Mark W.

2009-01-01

Atmospheric deposition of nitrogen (N) and sulfur (S) cause complex responses in ecosystems, from fertilization to forest ecosystem decline, freshwater eutrophication to acidification, loss of soil base cations, and alterations of disturbance regimes. DayCent-Chem, an ecosystem simulation model that combines ecosystem nutrient cycling and plant dynamics with aqueous geochemical equilibrium calculations, was developed to address ecosystem responses to combined atmospheric N and S deposition. It is unique among geochemically-based models in its dynamic biological cycling of N and its daily timestep for investigating ecosystem and surface water chemical response to episodic events. The model was applied to eight mountainous watersheds in the United States. The sites represent a gradient of N deposition across locales, from relatively pristine to N-saturated, and a variety of ecosystem types and climates. Overall, the model performed best in predicting stream chemistry for snowmelt-dominated sites. It was more difficult to predict daily stream chemistry for watersheds with deep soils, high amounts of atmospheric deposition, and a large degree of spatial heterogeneity. DayCent-Chem did well in representing plant and soil carbon and nitrogen pools and fluxes. Modeled stream nitrate (NO3-) and ammonium (NH4+) concentrations compared well with measurements at all sites, with few exceptions. Simulated daily stream sulfate (SO42-) concentrations compared well to measured values for sites where SO42- deposition has been low and where SO42- adsorption/desorption reactions did not seem to be important. The concentrations of base cations and silica in streams are highly dependent on the geochemistry and weathering rates of minerals in each catchment, yet these were rarely, if ever, known. Thus, DayCent-Chem could not accurately predict weathering products for some catchments. Additionally, few data were available for exchangeable soil cations or the magnitude of base cation

Using WRF-Chem to investigate the impact of night time nitrate radical chemistry and N2O5 heterogeneous chemistry on the chemical composition of the UK troposphere.

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Archer-Nicholls, S.; Lowe, D.; Utembe, S.; McFiggans, G.

2012-04-01

of two flight periods: one during July 2010; the other during January 2011. We have run five model scenarios for both these periods: a base case, with standard emissions and chemistry; two scenarios with standard chemistry, but with halved and doubled NOx transport emissions respectively; and two scenarios with standard emissions, but one without N2O5 heterogeneous chemistry, and the other with the Cl- reaction pathway disabled. We will present results from the application of WRF-Chem to model the regional chemical composition of the atmosphere about the UK. Sensitivities to changing emission profiles and the impact of N2O5 heterogeneous chemistry will be discussed. Preliminary comparisons between model results and aircraft data will be shown. The strengths and weaknesses of our modelling approach, in particular the gains and drawbacks of using a fully coupled online model for use in this campaign, will be highlighted. The wider impacts of the processes investigated on the regional climate and air quality will be further discussed. Allan, B., et. al. (2000); J. Geophys. Res., 105, doi: 10.1046/j.1365-2370.2000.00208. Bertram, T. H., Thornton, J. A. (2009); Atmos. Chem. Phys., 9, 8351-8363, doi: 10.5194/acp-9-8351-2009 Grell, G., et. al. (2005); Atmos. Environ., 39, 6957- 6975. doi: 10.1016/j.atmosenv.2005.04.027 Topping, D., Lowe, D. & McFiggans, G. (2012); Geosci. Model Dev., 5, 1-13. doi:10.5194/gmd-5-1-2012 Watson, L., et. al. (2008); Atmos. Environ., 42, 7196- 7204, doi: 10.1016/j.atmosenv.2008.07.034 Zaveri, R. A., et. al. (2008); J. Geophys. Res., 113, doi:10.1029/2007JD008782

Improvements to the WRF-Chem 3.5.1 model for quasi-hemispheric simulations of aerosols and ozone in the Arctic

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L. Marelle

2017-10-01

Full Text Available In this study, the WRF-Chem regional model is updated to improve simulated short-lived pollutants (e.g., aerosols, ozone in the Arctic. Specifically, we include in WRF-Chem 3.5.1 (with SAPRC-99 gas-phase chemistry and MOSAIC aerosols (1 a correction to the sedimentation of aerosols, (2 dimethyl sulfide (DMS oceanic emissions and gas-phase chemistry, (3 an improved representation of the dry deposition of trace gases over seasonal snow, and (4 an UV-albedo dependence on snow and ice cover for photolysis calculations. We also (5 correct the representation of surface temperatures over melting ice in the Noah Land Surface Model and (6 couple and further test the recent KF-CuP (Kain–Fritsch + Cumulus Potential cumulus parameterization that includes the effect of cumulus clouds on aerosols and trace gases. The updated model is used to perform quasi-hemispheric simulations of aerosols and ozone, which are evaluated against surface measurements of black carbon (BC, sulfate, and ozone as well as airborne measurements of BC in the Arctic. The updated model shows significant improvements in terms of seasonal aerosol cycles at the surface and root mean square errors (RMSEs for surface ozone, aerosols, and BC aloft, compared to the base version of the model and to previous large-scale evaluations of WRF-Chem in the Arctic. These improvements are mostly due to the inclusion of cumulus effects on aerosols and trace gases in KF-CuP (improved RMSE for surface BC and BC profiles, surface sulfate, and surface ozone, the improved surface temperatures over sea ice (surface ozone, BC, and sulfate, and the updated trace gas deposition and UV albedo over snow and ice (improved RMSE and correlation for surface ozone. DMS emissions and chemistry improve surface sulfate at all Arctic sites except Zeppelin, and correcting aerosol sedimentation has little influence on aerosols except in the upper troposphere.

Errors and improvements in the use of archived meteorological data for chemical transport modeling: an analysis using GEOS-Chem v11-01 driven by GEOS-5 meteorology

Directory of Open Access Journals (Sweden)

K. Yu

2018-01-01

Full Text Available Global simulations of atmospheric chemistry are commonly conducted with off-line chemical transport models (CTMs driven by archived meteorological data from general circulation models (GCMs. The off-line approach has the advantages of simplicity and expediency, but it incurs errors due to temporal averaging in the meteorological archive and the inability to reproduce the GCM transport algorithms exactly. The CTM simulation is also often conducted at coarser grid resolution than the parent GCM. Here we investigate this cascade of CTM errors by using 222Rn–210Pb–7Be chemical tracer simulations off-line in the GEOS-Chem CTM at rectilinear 0.25°  ×  0.3125° (≈ 25 km and 2°  ×  2.5° (≈ 200 km resolutions and online in the parent GEOS-5 GCM at cubed-sphere c360 (≈ 25 km and c48 (≈ 200 km horizontal resolutions. The c360 GEOS-5 GCM meteorological archive, updated every 3 h and remapped to 0.25°  ×  0.3125°, is the standard operational product generated by the NASA Global Modeling and Assimilation Office (GMAO and used as input by GEOS-Chem. We find that the GEOS-Chem 222Rn simulation at native 0.25°  ×  0.3125° resolution is affected by vertical transport errors of up to 20 % relative to the GEOS-5 c360 online simulation, in part due to loss of transient organized vertical motions in the GCM (resolved convection that are temporally averaged out in the 3 h meteorological archive. There is also significant error caused by operational remapping of the meteorological archive from a cubed-sphere to a rectilinear grid. Decreasing the GEOS-Chem resolution from 0.25°  ×  0.3125° to 2°  ×  2.5° induces further weakening of vertical transport as transient vertical motions are averaged out spatially and temporally. The resulting 222Rn concentrations simulated by the coarse-resolution GEOS-Chem are overestimated by up to 40 % in surface air relative to the

Air pollution modeling over very complex terrain: An evaluation of WRF-Chem over Switzerland for two 1-year periods

Science.gov (United States)

Ritter, Mathias; Müller, Mathias D.; Tsai, Ming-Yi; Parlow, Eberhard

2013-10-01

The fully coupled chemistry module (WRF-Chem) within the Weather Research and Forecasting (WRF) model has been implemented over a Swiss domain for the years 2002 and 1991. The very complex terrain requires a high horizontal resolution (2 × 2 km2), which is achieved by nesting the Swiss domain into a coarser European one. The temporal and spatial distribution of O3, NO2 and PM10 as well as temperature and solar radiation are evaluated against ground-based measurements. The model performs well for the meteorological parameters with Pearson correlation coefficients of 0.92 for temperature and 0.88-0.89 for solar radiation. Temperature has root mean square errors (RMSE) of 3.30 K and 3.51 K for 2002 and 1991 and solar radiation has RMSEs of 122.92 and 116.35 for 2002 and 1991, respectively. For the modeled air pollutants, a multi-linear regression post-processing was used to eliminate systematic bias. Seasonal variations of post-processed air pollutants are represented correctly. However, short-term peaks of several days are not captured by the model. Averaged daily maximum and daily values of O3 achieved Pearson correlation coefficients of 0.69-0.77 whereas averaged NO2 and PM10 had the highest correlations for yearly average values (0.68-0.78). The spatial distribution reveals the importance of PM10 advection from the Po valley to southern Switzerland (Ticino). The absolute errors are ranging from - 10 to 15 μg/m3 for ozone, - 9 to 3 μg/m3 for NO2 and - 4 to 3 μg/m3 for PM10. However, larger errors occur along heavily trafficked roads, in street canyons or on mountains. We also compare yearly modeled results against a dedicated Swiss dispersion model for NO2 and PM10. The dedicated dispersion model has a slightly better statistical performance, but WRF-Chem is capable of computing the temporal evolution of three-dimensional data for a variety of air pollutants and meteorological parameters. Overall, WRF-Chem with the application of post-processing algorithms can

The AtChem On-line model and Electronic Laboratory Notebook (ELN): A free community modelling tool with provenance capture

Science.gov (United States)

Young, J. C.; Boronska, K.; Martin, C. J.; Rickard, A. R.; Vázquez Moreno, M.; Pilling, M. J.; Haji, M. H.; Dew, P. M.; Lau, L. M.; Jimack, P. K.

2010-12-01

AtChem On-line1 is a simple to use zero-dimensional box modelling toolkit, developed for use by laboratory, field and chamber scientists. Any set of chemical reactions can be simulated, in particular the whole Master Chemical Mechanism (MCM2) or any subset of it. Parameters and initial data can be provided through a self-explanatory web form and the resulting model is compiled and run on a dedicated server. The core part of the toolkit, providing a robust solver for thousands of chemical reactions, is written in Fortran and uses SUNDIALS3 CVODE libraries. Chemical systems can be constrained at multiple, user-determined timescales; this enabled studies of radical chemistry at one minute timescales. AtChem On-line is free to use and requires no installation - a web browser, text editor and any compressing software is all the user needs. CPU and storage are provided by the server (input and output data are saved indefinitely). An off-line version is also being developed, which will provide batch processing, an advanced graphical user interface and post-processing tools, for example, Rate of Production Analysis (ROPA) and chainlength analysis. The source code is freely available for advanced users wishing to adapt and run the program locally. Data management, dissemination and archiving are essential in all areas of science. In order to do this in an efficient and transparent way, there is a critical need to capture high quality metadata/provenance for modelling activities. An Electronic Laboratory Notebook (ELN) has been developed in parallel with AtChem Online as part of the EC EUROCHAMP24 project. In order to use controlled chamber experiments to evaluate the MCM, we need to be able to archive, track and search information on all associated chamber model runs, so that they can be used in subsequent mechanism development. Therefore it would be extremely useful if experiment and model metadata/provenance could be easily and automatically stored electronically

Communication: Stiff and soft nano-environments and the "Octopus Effect" are the crux of ionic liquid structural and dynamical heterogeneity

Science.gov (United States)

Daly, Ryan P.; Araque, Juan C.; Margulis, Claudio J.

2017-08-01

In a recent set of articles [J. C. Araque et al., J. Phys. Chem. B 119(23), 7015-7029 (2015) and J. C. Araque et al., J. Chem. Phys. 144, 204504 (2016)], we proposed the idea that for small neutral and charged solutes dissolved in ionic liquids, deviation from simple hydrodynamic predictions in translational and rotational dynamics can be explained in terms of diffusion through nano-environments that are stiff (high electrostriction, charge density, and number density) and others that are soft (charge depleted). The current article takes a purely solvent-centric approach in trying to provide molecular detail and intuitive visual understanding of time-dependent local mobility focusing on the most common case of an ionic liquid with well defined polar and apolar nano-domains. We find that at intermediate time scales, apolar regions are fluid, whereas the charge network is much less mobile. Because apolar domains and cationic heads must diffuse as single species, at long time the difference in mobility also necessarily dissipates.

Open-water and under-ice seasonal variations in trace element content and physicochemical associations in fluvial bed sediment.

Science.gov (United States)

Doig, Lorne E; Carr, Meghan K; Meissner, Anna G N; Jardine, Tim D; Jones, Paul D; Bharadwaj, Lalita; Lindenschmidt, Karl-Erich

2017-11-01

. Environ Toxicol Chem 2017;36:2916-2924. © 2017 SETAC. © 2017 SETAC.

Diclofenac degradation by heterogeneous photocatalysis with Fe3O4/Ti x O y /activated carbon fiber composite synthesized by ultrasound irradiation

Science.gov (United States)

Moreno-Valencia, E. I.; Paredes-Carrera, S. P.; Sánchez-Ochoa, J. C.; Flores-Valle, S. O.; Avendaño-Gómez, J. R.

2017-11-01

In this work, a photocatalytic system to degrade diclofenac was developed using a composite Fe3O4/Ti x O y on an activated carbon fiber. Diclofenac is widely used as an anti-inflammatory compound worldwide and it is constantly being added as waste in the environment (Heberer 2002 J. Hydrol. 266 175-89), exceeding the permissible maximum concentration in the wastewater (GEO-3 2002 Programa de las Naciones Unidas para el Medio Ambiente; Golet et al 2003 Environ. Sci. Technol. 37 3243-9 Oviedo et al 2010 Environ. Toxicol. Pharmacol. 29 9-43 Le-Minh et al 2010 Water Res. 44 4295-323 Legrini et al 1993 Chem. Rev. 1093 671-98). The composite was synthesized by sol-gel technique with and without ultrasound irradiation (Singh and Nakate 2014 J. Nanopart. 2014 326747). The solids were deposited by ultrasound irradiation on active carbon fiber in order to optimize the diclofenac degradation. The solids were characterized by x-ray diffraction (XRD), nitrogen physisorption (BET), and scanning electron microscopy with EDS microanalysis (SEM-EDS). The crystal size was calculated with the Debye-Scherrer equation, and the band gap values by the diffuse reflectance method. The evaluation process was studied by UV-vis spectroscopy (Rizzoa et al 2009 Water Res. 43 979-88). It was found that in this synthesis method (ultrasound), textural properties such as porosity, specific surface area and morphology depend on the ultrasound irradiation. The proposed system, Fe3O4/titanium oxide hydrate showed better degradation profile than TiO2 anatase phase; the increase of diclofenac degradation was attributed to the textural properties of the composite, it avoids the filtering process since the separation can be achieved by magnetizing and/or decantation.

Intoxicação alcoólica em crianças e adolescentes: dados de um centro de assistência toxicológica Intoxicación alcohólica en niños y adolescentes: datos de un centro de asistencia toxicológica Alcoholic intoxication in children and adolescents: information from an intoxication control center

Directory of Open Access Journals (Sweden)

Magda Lúcia Félix de Oliveira

2011-03-01

Full Text Available O abuso de álcool constitui um dos problemas sociais e de saúde de grande magnitude em nosso tempo. O estudo teve como objetivo caracterizar as ocorrências toxicológicas em crianças e adolescentes com idade até 18 anos, hospitalizados por intoxicação alcoólica e notificados em um Centro de Controle de Intoxicação nos anos de 2003 a 2007. O estudo foi retrospectivo, com análise quantitativa dos dados. Encontraram-se 338 notificações. O abuso de álcool ocorreu predominantemente no sexo masculino, sendo os finais de semana, o período noturno e o uso agudo de maior ocorrência. A intoxicação alcoólica relacionada às ocorrências violentas aumentou em 12 vezes as chances de internação, e observou-se relação significativa entre o uso crônico e o aumento da gravidade clínica. Sugere-se estudos para aprofundar a temática e a implementação de políticas e estratégias preventivas tendo a criança e o adolescente como foco principal.El abuso del alcohol constituye uno de los problemas sociales y de salud de gran proporción en los tiempos de hoy. El estudio tuvo como objetivo caracterizar las ocurrencias toxicológicas en niños y adolescentes hasta los 18 años de edad, acogidos por intoxicación alcohólica y notificados en un Centro de Control de Intoxicación en los años de 2003 a 2007. El estudio fue retrospectivo, con análisis cuantitativo de los datos. Se ha encontrado 338 notificaciones. El abuso del alcohol ocurrió predominantemente en el sexo masculino, con mayor uso en los fines de semana, en el periodo nocturno. La intoxicación alcohólica relacionada a las ocurrencias violentas ha aumentado en 12 veces las oportunidades de internación y se observa relación significativa entre el uso crónico y el aumento de la gravedad clínica. Se sugiere estudios para profundizar el tema y la implementación de políticas y estrategias de prevención, en que los niños y adolescentes son en foco principal.Alcohol abuse is

Ikhajiagbe (8)

African Journals Online (AJOL)

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Residual concentration of Cd in soil was 0.22 mg/kg in the soil originally polluted with 6.66 mg. (Cd)/kg, compared to a ... Some of these nutrients are heavy metals like Zn and Cu which are essential ..... of Flvonoids interactions with Cu ions: ... simultaneous exposure to cadmium and lead. Arch. Environ. Contam. Toxicol.

A Novel Approach for Predicting Sublethal Effects of Toxicants to Aquatic Organisms

Science.gov (United States)

1984-11-30

Ramos, F., and Smith, A. C. (1978). Ketone bodies in fish skin mucous as a indicator of starvation: A preliminary report. J. Fish Biol. 12:105-108...Bull. Environ. Contam. Toxicol. 21:79-84. Smith, A. C., and Ramos, F. (1976). Occult haemoglobin in fish skin mucous as an indicator of early stress. J

Source apportionment of atmospheric mercury pollution in China using the GEOS-Chem model.

Science.gov (United States)

Wang, Long; Wang, Shuxiao; Zhang, Lei; Wang, Yuxuan; Zhang, Yanxu; Nielsen, Chris; McElroy, Michael B; Hao, Jiming

2014-07-01

China is the largest atmospheric mercury (Hg) emitter in the world. Its Hg emissions and environmental impacts need to be evaluated. In this study, China's Hg emission inventory is updated to 2007 and applied in the GEOS-Chem model to simulate the Hg concentrations and depositions in China. Results indicate that simulations agree well with observed background Hg concentrations. The anthropogenic sources contributed 35-50% of THg concentration and 50-70% of total deposition in polluted regions. Sensitivity analysis was performed to assess the impacts of mercury emissions from power plants, non-ferrous metal smelters and cement plants. It is found that power plants are the most important emission sources in the North China, the Yangtze River Delta (YRD) and the Pearl River Delta (PRD) while the contribution of non-ferrous metal smelters is most significant in the Southwest China. The impacts of cement plants are significant in the YRD, PRD and Central China. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ecotoxicological assessment of glyphosate-based herbicides: Effects on different organisms.

Science.gov (United States)

de Brito Rodrigues, Laís; de Oliveira, Rhaul; Abe, Flávia Renata; Brito, Lara Barroso; Moura, Diego Sousa; Valadares, Marize Campos; Grisolia, Cesar Koppe; de Oliveira, Danielle Palma; de Oliveira, Gisele Augusto Rodrigues

2017-07-01

Glyphosate-based herbicides are the most commonly used worldwide because they are effective and relatively nontoxic to nontarget species. Unlimited and uncontrolled use of such pesticides can have serious consequences for human health and ecological balance. The present study evaluated the acute toxicity and genotoxicity of 2 glyphosate-based formulations, Roundup Original (Roundup) and Glyphosate AKB 480 (AKB), on different organisms: cucumber (Cucumis sativus), lettuce (Lactuca sativa), and tomato (Lycopersicon esculentum) seeds, and microcrustacean Artemia salina and zebrafish (Danio rerio) early life stages. For the germination endpoint, only L. esculentum presented significant sensitivity to AKB and L. sativa to Roundup, whereas both formulations significantly inhibited the root growth of all species tested. Both AKB and Roundup induced significant toxicity to A. salina; both are classified as category 3, which indicates a hazard for the aquatic environment, according to criteria of the Globally Harmonized Classification System. However, Roundup was more toxic than AKB, with 48-h median lethal concentration (LC50) values of 14.19 mg/L and 37.53 mg/L, respectively. For the embryo-larval toxicity test, Roundup proved more toxic than AKB for the mortality endpoint (96-h LC50 values of 10.17 mg/L and 27.13 mg/L, respectively), whereas for the hatching parameter, AKB was more toxic than Roundup. No significant genotoxicity to zebrafish larvae was found. We concluded that AKB and Roundup glyphosate-based formulations are phytotoxic and induce toxic effects in nontarget organisms such as A. salina and zebrafish early life stages. Environ Toxicol Chem 2017;36:1755-1763. © 2016 SETAC. © 2016 SETAC.

Determination of silicone rubber and low-density polyethylene diffusion and polymer/water partition coefficients for emerging contaminants.

Science.gov (United States)

Pintado-Herrera, Marina G; Lara-Martín, Pablo A; González-Mazo, Eduardo; Allan, Ian J

2016-09-01

There is a growing interest in assessing the concentration and distribution of new nonregulated organic compounds (emerging contaminants) in the environment. The measurement of freely dissolved concentrations using conventional approaches is challenging because of the low concentrations that may be encountered and their temporally variable emissions. Absorption-based passive sampling enables the estimation of freely dissolved concentrations of hydrophobic contaminants of emerging concern in water. In the present study, calibration was undertaken for 2 polymers, low-density polyethylene (LDPE) and silicone rubber for 11 fragrances, 5 endocrine-disrupting compounds, 7 ultraviolet (UV) filters, and 8 organophosphate flame retardant compounds. Batch experiments were performed to estimate contaminant diffusion coefficients in the polymers (Dp ), which in general decreased with increasing molecular weight. The values for fragrances, endocrine-disrupting compounds, and UV filters were in ranges similar to those previously reported for polycyclic aromatic hydrocarbons, but were 1 order of magnitude lower for organophosphate flame retardant compounds. Silicone rubber had higher Dp values than LDPE and was therefore selected for further experiments to calculate polymer/water partition coefficients (KPW ). The authors observed a positive correlation between log KPW and log octanol/water partition coefficient values. Field testing of silicone rubber passive samplers was undertaken though exposure in the River Alna (Norway) for an exposure time of 21 d to estimate freely dissolved concentration. Some fragrances and UV filters were predominant over other emerging and regulated contaminants, at levels up to 1600 ng L(-1) for galaxolide and 448 ng L(-1) for octocrylene. Environ Toxicol Chem 2016;35:2162-2172. © 2016 SETAC. © 2016 SETAC.

Combined effects of road salt and an insecticide on wetland communities.

Science.gov (United States)

Stoler, Aaron B; Walker, Brent M; Hintz, William D; Jones, Devin K; Lind, Lovisa; Mattes, Brian M; Schuler, Matthew S; Relyea, Rick A

2017-03-01

As the numbers of chemical contaminants in freshwater ecosystems increase, it is important to understand whether contaminants interact in ecologically important ways. The present study investigated the independent and interactive effects of 2 contaminants that frequently co-occur in freshwater environments among higher latitudes, including a commonly applied insecticide (carbaryl) and road salt (NaCl). The hypothesis was that the addition of either contaminant would result in a decline in zooplankton, an algal bloom, and the subsequent decline of both periphyton and periphyton consumers. Another hypothesis was that combining the contaminants would result in synergistic effects on community responses. Outdoor mesocosms were used with communities that included phytoplankton, periphyton, zooplankton, amphipods, clams, snails, and tadpoles. Communities were exposed to 4 environmentally relevant concentrations of salt (27 mg Cl - L -1 , 77 mg Cl - L -1 , 277 mg Cl - L -1 , and 727 mg Cl - L -1 ) fully crossed with 4 carbaryl treatments (ethanol, 0 µg L -1 , 5 µg L -1 , and 50 µg L -1 ) over 57 d. Contaminants induced declines in rotifer and cladoceran zooplankton, but only carbaryl induced an algal bloom. Consumers exhibited both positive and negative responses to contaminants, which were likely the result of both indirect community interactions and direct toxicity. In contrast to the hypothesis, no synergistic effects were found, although copepod densities declined when high concentrations of both chemicals were combined. The results suggest that low concentrations of salt and carbaryl are likely to have mostly independent effects on aquatic communities. Environ Toxicol Chem 2017;36:771-779. © 2016 SETAC. © 2016 SETAC.

Ecotoxicological properties of ketoprofen and the S(+)-enantiomer (dexketoprofen): Bioassays in freshwater model species and biomarkers in fish PLHC-1 cell line.

Science.gov (United States)

Mennillo, Elvira; Arukwe, Augustine; Monni, Gianfranca; Meucci, Valentina; Intorre, Luigi; Pretti, Carlo

2018-01-01

The increased use of nonsteroidal anti-inflammatory drugs (NSAIDs) has resulted in their ubiquitous presence in the environment. The toxicological properties of these 2 widely prescribed NSAIDs, namely racemic ketoprofen and its enantiomer S(+)-ketoprofen (dexketoprofen), were evaluated, firstly, by acute and chronic toxicity tests using 3 representative model organisms (Vibrio fischeri, Pseudokirchneriella subcapitata, and Ceriodaphnia dubia) and, secondly, by evaluating the responses of biotransformation systems and multidrug resistance-associated proteins (MRP1/MRP2) using the Poeciliopsis lucida hepatocellular carcinoma 1 (PLHC-1) fish hepatic cell line. Toxicity data from both acute and chronic dexketoprofen exposure indicated higher sensitivity through inhibition of bioluminescence and algal growth and through increased mortality/immobilization compared to racemic ketoprofen exposure. The growth inhibition test showed that racemic ketoprofen and dexketoprofen exhibited different effect concentration values (240.2 and 65.6 μg/L, respectively). Furthermore, racemic ketoprofen and dexketoprofen did not exert cytotoxic effects in PLHC-1 cells and produced compound-, time-, and concentration-specific differential effects on cytochrome P450 1A (CYP1A) and glutathione S-transferase levels. For CYP1A, the effects of racemic ketoprofen and dexketoprofen differed at the transcriptional and catalytic levels. Exposure to racemic ketoprofen and dexketoprofen modulated MRP1 and MRP2 mRNA levels, and these effects were also dependent on compound, exposure time, and concentration of the individual drug. The present study revealed for the first time the interactions between these NSAIDs and key detoxification systems and different sensitivity to the racemic mixture compared to its enantiomer. Environ Toxicol Chem 2018;37:201-212. © 2017 SETAC. © 2017 SETAC.

Monoterpenoid-based preparations in beehives affect learning, memory, and gene expression in the bee brain.

Science.gov (United States)

Bonnafé, Elsa; Alayrangues, Julie; Hotier, Lucie; Massou, Isabelle; Renom, Allan; Souesme, Guillaume; Marty, Pierre; Allaoua, Marion; Treilhou, Michel; Armengaud, Catherine

2017-02-01

Bees are exposed in their environment to contaminants that can weaken the colony and contribute to bee declines. Monoterpenoid-based preparations can be introduced into hives to control the parasitic mite Varroa destructor. The long-term effects of monoterpenoids are poorly investigated. Olfactory conditioning of the proboscis extension reflex (PER) has been used to evaluate the impact of stressors on cognitive functions of the honeybee such as learning and memory. The authors tested the PER to odorants on bees after exposure to monoterpenoids in hives. Octopamine receptors, transient receptor potential-like (TRPL), and γ-aminobutyric acid channels are thought to play a critical role in the memory of food experience. Gene expression levels of Amoa1, Rdl, and trpl were evaluated in parallel in the bee brain because these genes code for the cellular targets of monoterpenoids and some pesticides and neural circuits of memory require their expression. The miticide impaired the PER to odors in the 3 wk following treatment. Short-term and long-term olfactory memories were improved months after introduction of the monoterpenoids into the beehives. Chronic exposure to the miticide had significant effects on Amoa1, Rdl, and trpl gene expressions and modified seasonal changes in the expression of these genes in the brain. The decrease of expression of these genes in winter could partly explain the improvement of memory. The present study has led to new insights into alternative treatments, especially on their effects on memory and expression of selected genes involved in this cognitive function. Environ Toxicol Chem 2017;36:337-345. © 2016 SETAC. © 2016 SETAC.

Testicular oocytes in smallmouth bass in northeastern Minnesota in relation to varying levels of human activity.

Science.gov (United States)

Kadlec, Sarah M; Johnson, Rodney D; Mount, David R; Olker, Jennifer H; Borkholder, Brian D; Schoff, Patrick K

2017-12-01

Testicular oocytes (TOs) have been found in black bass (Micropterus spp.) from many locations in North America. The presence of TOs is often assumed to imply exposure to estrogenic endocrine disrupting compounds (EDCs); however, a definitive causal relationship has yet to be established, and TO prevalence is not consistently low in fish from areas lacking evident EDC sources. This might indicate any of a number of situations: 1) unknown or unidentified EDCs or EDC sources, 2) induction of TOs by other stressors, or 3) testicular oocytes occurring spontaneously during normal development. In the present study, we analyzed TO occurrence in smallmouth bass (Micropterus dolomieu) from 8 populations in northeastern Minnesota watersheds with differing degrees of human development and, hence, presumed likelihood of exposure to anthropogenic chemicals. Three watersheds were categorized as moderately developed, based on the presence of municipal wastewater discharges and higher human population density (4-81 per km 2 ), and 5 watersheds were minimally developed, with very low human population density (0-1 per km 2 ) and minimal built environment. Testicular tissues from mature fish were evaluated using a semiquantitative method that estimated TO density, normalized by cross-sectional area. Testicular oocyte prevalence and density among populations from moderately developed watersheds was higher than in populations from minimally developed watersheds. However, TO prevalence was unexpectedly high and variable (7-43%) in some populations from minimally developed watersheds, and only weak evidence was found for a relationship between TO density and watershed development, suggesting alternative or more complex explanations for TO presence in smallmouth bass from this region. Environ Toxicol Chem 2017;36:3424-3435. © 2017 SETAC. © 2017 SETAC.

Widespread occurrence and potential for biodegradation of bioactive contaminants in Congaree National Park, USA.

Science.gov (United States)

Bradley, Paul M; Battaglin, William A; Clark, Jimmy M; Henning, Frank P; Hladik, Michelle L; Iwanowicz, Luke R; Journey, Celeste A; Riley, Jeffrey W; Romanok, Kristin M

2017-11-01

Organic contaminants with designed molecular bioactivity, such as pesticides and pharmaceuticals, originate from human and agricultural sources, occur frequently in surface waters, and threaten the structure and function of aquatic and terrestrial ecosystems. Congaree National Park in South Carolina (USA) is a vulnerable park unit due to its location downstream of multiple urban and agricultural contaminant sources and its hydrologic setting, being composed almost entirely of floodplain and aquatic environments. Seventy-two water and sediment samples were collected from 16 sites in Congaree National Park during 2013 to 2015, and analyzed for 199 and 81 targeted organic contaminants, respectively. More than half of these water and sediment analytes were not detected or potentially had natural sources. Pharmaceutical contaminants were detected (49 total) frequently in water throughout Congaree National Park, with higher detection frequencies and concentrations at Congaree and Wateree River sites, downstream from major urban areas. Forty-seven organic wastewater indicator chemicals were detected in water, and 36 were detected in sediment, of which approximately half are distinctly anthropogenic. Endogenous sterols and hormones, which may originate from humans or wildlife, were detected in water and sediment samples throughout Congaree National Park, but synthetic hormones were detected only once, suggesting a comparatively low risk of adverse impacts. Assessment of the biodegradation potentials of 8 14 C-radiolabeled model contaminants indicated poor potentials for some contaminants, particularly under anaerobic sediments conditions. Environ Toxicol Chem 2017;36:3045-3056. Published 2017 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. © 2017 SETAC.

Is ozone model bias driven by errors in cloud predictions? A quantitative assessment using satellite cloud retrievals in WRF-Chem

Science.gov (United States)

Ryu, Y. H.; Hodzic, A.; Barré, J.; Descombes, G.; Minnis, P.

2017-12-01

Clouds play a key role in radiation and hence O3 photochemistry by modulating photolysis rates and light-dependent emissions of biogenic volatile organic compounds (BVOCs). It is not well known, however, how much of the bias in O3 predictions is caused by inaccurate cloud predictions. This study quantifies the errors in surface O3 predictions associated with clouds in summertime over CONUS using the Weather Research and Forecasting with Chemistry (WRF-Chem) model. Cloud fields used for photochemistry are corrected based on satellite cloud retrievals in sensitivity simulations. It is found that the WRF-Chem model is able to detect about 60% of clouds in the right locations and generally underpredicts cloud optical depths. The errors in hourly O3 due to the errors in cloud predictions can be up to 60 ppb. On average in summertime over CONUS, the errors in 8-h average O3 of 1-6 ppb are found to be attributable to those in cloud predictions under cloudy sky conditions. The contribution of changes in photolysis rates due to clouds is found to be larger ( 80 % on average) than that of light-dependent BVOC emissions. The effects of cloud corrections on O­3 are about 2 times larger in VOC-limited than NOx-limited regimes, suggesting that the benefits of accurate cloud predictions would be greater in VOC-limited than NOx-limited regimes.

Pre-flight calibration and initial data processing for the ChemCam laser-induced breakdown spectroscopy instrument on the Mars Science Laboratory rover

Science.gov (United States)

Wiens, R.C.; Maurice, S.; Lasue, J.; Forni, O.; Anderson, R.B.; Clegg, S.; Bender, S.; Blaney, D.; Barraclough, B.L.; Cousin, A.; DeFlores, L.; Delapp, D.; Dyar, M.D.; Fabre, C.; Gasnault, O.; Lanza, N.; Mazoyer, J.; Melikechi, N.; Meslin, P.-Y.; Newsom, H.; Ollila, A.; Perez, R.; Tokar, R.; Vaniman, D.

2013-01-01

The ChemCam instrument package on the Mars Science Laboratory rover, Curiosity, is the first planetary science instrument to employ laser-induced breakdown spectroscopy (LIBS) to determine the compositions of geological samples on another planet. Pre-processing of the spectra involves subtracting the ambient light background, removing noise, removing the electron continuum, calibrating for the wavelength, correcting for the variable distance to the target, and applying a wavelength-dependent correction for the instrument response. Further processing of the data uses multivariate and univariate comparisons with a LIBS spectral library developed prior to launch as well as comparisons with several on-board standards post-landing. The level-2 data products include semi-quantitative abundances derived from partial least squares regression. A LIBS spectral library was developed using 69 rock standards in the form of pressed powder disks, glasses, and ceramics to minimize heterogeneity on the scale of the observation (350–550 μm dia.). The standards covered typical compositional ranges of igneous materials and also included sulfates, carbonates, and phyllosilicates. The provenance and elemental and mineralogical compositions of these standards are described. Spectral characteristics of this data set are presented, including the size distribution and integrated irradiances of the plasmas, and a proxy for plasma temperature as a function of distance from the instrument. Two laboratory-based clones of ChemCam reside in Los Alamos and Toulouse for the purpose of adding new spectra to the database as the need arises. Sensitivity to differences in wavelength correlation to spectral channels and spectral resolution has been investigated, indicating that spectral registration needs to be within half a pixel and resolution needs to match within 1.5 to 2.6 pixels. Absolute errors are tabulated for derived compositions of each major element in each standard using PLS regression

Constraints on Eurasian ship NOx emissions using OMI NO2 observations and GEOS-Chem

Science.gov (United States)

Vinken, Geert C. M.; Boersma, Folkert; van Donkelaar, Aaron; Zhang, Lin

2013-04-01

Ships emit large quantities of nitrogen oxides (NOx = NO + NO2), important precursors for ozone (O3) and particulate matter formation. Ships burn low-grade marine heavy fuel due to the limited regulations that exist for the maritime sector in international waters. Previous studies showed that global ship NOx emission inventories amount to 3.0-10.4 Tg N per year (15-30% of total NOx emissions), with most emissions close to land and affecting air quality in densely populated coastal regions. Bottom-up inventories depend on the extrapolation of a relatively small number of measurements that are often unable to capture annual emission changes and can suffer from large uncertainties. Satellites provide long-term, high-resolution retrievals that can be used to improve emission estimates. In this study we provide top-down constraints on ship NOx emissions in major European ship routes, using observed NO2 columns from the Ozone Monitoring Instrument (OMI) and NO2 columns simulated with the nested (0.5°×0.67°) version of the GEOS-Chem chemistry transport model. We use a plume-in-grid treatment of ship NOx emissions to account for in-plume chemistry in our model. We ensure consistency between the retrievals and model simulations by using the high-resolution GEOS-Chem NO2 profiles as a priori. We find evidence that ship emissions in the Mediterranean Sea are geographically misplaced by up to 150 km and biased high by a factor of 4 as compared to the most recent (EMEP) ship emission inventory. Better agreement is found over the shipping lane between Spain and the English Channel. We extend our approach and also provide constraints for major ship routes in the Red Sea and Indian Ocean. Using the full benefit of the long-term retrieval record of OMI, we present a new Eurasian ship emission inventory for the years 2005 to 2010, based on the EMEP and AMVER-ICOADS inventories, and top-down constraints from the satellite retrievals. Our work shows that satellite retrievals can

El Sensor Químico (ChemSensor) como herramienta complementaria en el análisis sensorial de vinos

OpenAIRE

Pérez Mateos, Miriam; Giménez Cobo, Lucia; Carrasco Manzano, Juan Atanasio

2012-01-01

El Sensor Químico (ChemSensor) o pseudo-nariz electrónica determina la agrupación de alimentos por similitudes y según la distancias entre grupos, a partir del análisis de espectrometría de masas de los compuestos volátiles y/o los ácidos grasos. Se trata de una herramienta excelente como complemento al análisis sensorial. Es muy útil en la clasificación y predicción de productos alimenticios según su origen, procesado y conservación; en la optimización de procesos y en aplicaciones de contro...

Inhibition of immune responses and related proteins in Rhamdia quelen exposed to diclofenac.

Science.gov (United States)

Ribas, João L C; Sherry, James P; Zampronio, Aleksander R; Silva de Assis, Helena C; Simmons, Denina B D

2017-08-01

Nonsteroidal anti-inflammatory drugs are among the most widely detected pharmaceuticals in surface water worldwide. The nonsteroidal anti-inflammatory drug diclofenac is used to treat many types of pain and inflammation. Diclofenac's potential to cause adverse effects in exposed wildlife is a growing concern. To evaluate the effects of waterborne diclofenac on the immune response in Rhamdia quelen (South American catfish), fish were exposed to 3 concentrations of diclofenac (0.2, 2.0, and 20.0 μg/L) for 14 d. Some of the exposed fish were also given an intraperitoneal injection on day 14 of 1 mg/kg of carrageenan to evaluate cell migration to the peritoneum. Total blood leukocyte count and carrageenan-induced leukocyte migration to the peritoneal cavity, particularly of polymorphonuclear cells, were significantly affected for all diclofenac exposure groups. Nitric oxide production was significantly reduced in the diclofenac-treated fish. Plasma and kidney proteins were analyzed by means of liquid chromatography-tandem mass spectrometry in a shotgun proteomic approach. In both plasma and kidney of diclofenac-exposed R. quelen, the expression of 20 proteins related to the inflammatory process, nitric oxide production, leukocyte migration, and the complement cascade was significantly altered. In addition, class I major histocompatibility complex was significantly decreased in plasma of diclofenac-treated fish. Thus, waterborne exposure to diclofenac could lead to suppression of the innate immune system in R. quelen. Environ Toxicol Chem 2017;36:2092-2107. © 2017 SETAC. © 2017 SETAC.

Predictive framework for estimating exposure of birds to pharmaceuticals.

Science.gov (United States)

Bean, Thomas G; Arnold, Kathryn E; Lane, Julie M; Bergström, Ed; Thomas-Oates, Jane; Rattner, Barnett A; Boxall, Alistair B A

2017-09-01

We present and evaluate a framework for estimating concentrations of pharmaceuticals over time in wildlife feeding at wastewater treatment plants (WWTPs). The framework is composed of a series of predictive steps involving the estimation of pharmaceutical concentration in wastewater, accumulation into wildlife food items, and uptake by wildlife with subsequent distribution into, and elimination from, tissues. Because many pharmacokinetic parameters for wildlife are unavailable for the majority of drugs in use, a read-across approach was employed using either rodent or human data on absorption, distribution, metabolism, and excretion. Comparison of the different steps in the framework against experimental data for the scenario where birds are feeding on a WWTP contaminated with fluoxetine showed that estimated concentrations in wastewater treatment works were lower than measured concentrations; concentrations in food could be reasonably estimated if experimental bioaccumulation data are available; and read-across from rodent data worked better than human to bird read-across. The framework provides adequate predictions of plasma concentrations and of elimination behavior in birds but yields poor predictions of distribution in tissues. The approach holds promise, but it is important that we improve our understanding of the physiological similarities and differences between wild birds and domesticated laboratory mammals used in pharmaceutical efficacy/safety trials, so that the wealth of data available can be applied more effectively in ecological risk assessments. Environ Toxicol Chem 2017;36:2335-2344. © 2017 SETAC. © 2017 SETAC.

Linking field-based metabolomics and chemical analyses to prioritize contaminants of emerging concern in the Great Lakes basin

Science.gov (United States)

Davis, John M.; Ekman, Drew R.; Teng, Quincy; Ankley, Gerald T.; Berninger, Jason P.; Cavallin, Jenna E.; Jensen, Kathleen M.; Kahl, Michael D.; Schroeder, Anthony L.; Villeneuve, Daniel L.; Jorgenson, Zachary G.; Lee, Kathy E.; Collette, Timothy W.

2016-01-01

The ability to focus on the most biologically relevant contaminants affecting aquatic ecosystems can be challenging because toxicity-assessment programs have not kept pace with the growing number of contaminants requiring testing. Because it has proven effective at assessing the biological impacts of potentially toxic contaminants, profiling of endogenous metabolites (metabolomics) may help screen out contaminants with a lower likelihood of eliciting biological impacts, thereby prioritizing the most biologically important contaminants. The authors present results from a study that utilized cage-deployed fathead minnows (Pimephales promelas) at 18 sites across the Great Lakes basin. They measured water temperature and contaminant concentrations in water samples (132 contaminants targeted, 86 detected) and used 1H-nuclear magnetic resonance spectroscopy to measure endogenous metabolites in polar extracts of livers. They used partial least-squares regression to compare relative abundances of endogenous metabolites with contaminant concentrations and temperature. The results indicated that profiles of endogenous polar metabolites covaried with at most 49 contaminants. The authors identified up to 52% of detected contaminants as not significantly covarying with changes in endogenous metabolites, suggesting they likely were not eliciting measurable impacts at these sites. This represents a first step in screening for the biological relevance of detected contaminants by shortening lists of contaminants potentially affecting these sites. Such information may allow risk assessors to prioritize contaminants and focus toxicity testing on the most biologically relevant contaminants. Environ Toxicol Chem 2016;35:2493–2502.

Interaction of single-walled carbon nanotubes and saxitoxin: Ab initio simulations and biological responses in hippocampal cell line HT-22.

Science.gov (United States)

Ramos, Patrícia; Schmitz, Marcos; Filgueira, Daza; Votto, Ana Paula; Durruthy, Michael; Gelesky, Marcos; Ruas, Caroline; Yunes, João; Tonel, Mariana; Fagan, Solange; Monserrat, José

2017-07-01

Saxitoxins (STXs) are potent neurotoxins that also induce cytotoxicity through the generation of reactive oxygen species. Carbon nanotubes (CNTs) are nanomaterials that can promote a Trojan horse effect, facilitating the entry of toxic molecules to cells when adsorbed to nanomaterials. The interaction of pristine single-walled (SW)CNTs and carboxylated (SWCNT-COOH) nanotubes with STX was evaluated by ab initio simulation and bioassays using the cell line HT-22. Cells (5 × 10 4  cells/mL) were exposed to SWCNT and SWCNT-COOH (5 μg mL -1 ), STX (200 μg L -1 ), SWCNT+STX, and SWCNT-COOH+STX for 30 min or 24 h. Results of ab initio simulation showed that the interaction between SWCNT and SWCNT-COOH with STX occurs in a physisorption. The interaction of SWCNT+STX induced a decrease in cell viability. Cell proliferation was not affected in any treatment after 30 min or 24 h of exposure (p > 0.05). Treatment with SWCNT-COOH induced high reactive oxygen species levels, an effect attenuated in SWCNT-COOH+STX treatment. In terms of cellular oxygen consumption, both CNTs when coexposed with STX antagonize the toxin effect. Based on these results, it can be concluded that the results obtained in vitro corroborate the semiempirical evidence found using density functional theory ab initio simulation. Environ Toxicol Chem 2017;36:1728-1737. © 2016 SETAC. © 2016 SETAC.

Great horned owl (Bubo virginianus) dietary exposure to PCDD/DF in the Tittabawassee River floodplain in Midland, Michigan, USA.

Science.gov (United States)

Coefield, Sarah J; Zwiernik, Matthew J; Fredricks, Timothy B; Seston, Rita M; Nadeau, Michael W; Tazelaar, Dustin L; Moore, Jeremy N; Kay, Denise P; Roark, Shaun A; Giesy, John P

2010-10-01

Soils and sediments in the floodplain of the Tittabawassee River downstream of Midland, Michigan, USA contain elevated concentrations of polychlorinated dibenzofurans (PCDF) and polychlorinated dibenzo-p-dioxins (PCDD). As a long-lived, resident top predator, the great horned owl (Bubo virginianus; GHO) has the potential to be exposed to bioaccumulative compounds such as PCDD/DF. Site-specific components of the GHO diet were collected along 115 km of the Tittabawassee, Pine, Chippewa, and Saginaw Rivers during 2005 and 2006. The site-specific GHO biomass-based diet was dominated by cottontail rabbits (Sylvilagus floridanus) and muskrats (Ondatra zibethicus). Incidental soil ingestion and cottontail rabbits were the primary contributors of PCDD/DF to the GHO diet. The great horned owl daily dietary exposure estimates were greater in the study area (SA) (3.3 to 5.0 ng 2,3,7,8-TCDD equivalents (TEQ(WHO-avian))/kg body wt/d) than the reference area (RA) (0.07 ng TEQ(WHO-Avian)/kg body wt/d). Hazard quotients (HQs) based on central tendency estimates of the average daily dose and no-observable-adverse effect level (NOAEL) for the screech owl and uncertainty factors were <1.0 for both the RA and the SA. Hazard quotients based on upper end estimates of the average daily dose and NOAEL were <1.0 in the RA and up to 3.4 in the SA. Environ. Toxicol. Chem. 2010;29:2350-2362. © 2010 SETAC.

Mercury exposure may influence fluctuating asymmetry in waterbirds.

Science.gov (United States)

Herring, Garth; Eagles-Smith, Collin A; Ackerman, Joshua T

2017-06-01

Variation in avian bilateral symmetry can be an indicator of developmental instability in response to a variety of stressors, including environmental contaminants. The authors used composite measures of fluctuating asymmetry to examine the influence of mercury concentrations in 2 tissues on fluctuating asymmetry within 4 waterbird species. Fluctuating asymmetry increased with mercury concentrations in whole blood and breast feathers of Forster's terns (Sterna forsteri), a species with elevated mercury concentrations. Specifically, fluctuating asymmetry in rectrix feather 1 was the most strongly correlated structural variable of those tested (wing chord, tarsus, primary feather 10, rectrix feather 6) with mercury concentrations in Forster's terns. However, for American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), and Caspian terns (Hydroprogne caspia), the authors found no relationship between fluctuating asymmetry and either whole-blood or breast feather mercury concentrations, even though these species had moderate to elevated mercury exposure. The results indicate that mercury contamination may act as an environmental stressor during development and feather growth and contribute to fluctuating asymmetry of some species of highly contaminated waterbirds. Environ Toxicol Chem 2017;36:1599-1605. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Resolving the false-negative issues of the nonpolar organic amendment in whole-sediment toxicity identification evaluations.

Science.gov (United States)

Mehler, W Tyler; Keough, Michael J; Pettigrove, Vincent

2018-04-01

Three common false-negative scenarios have been encountered with amendment addition in whole-sediment toxicity identification evaluations (TIEs): dilution of toxicity by amendment addition (i.e., not toxic enough), not enough amendment present to reduce toxicity (i.e., too toxic), and the amendment itself elicits a toxic response (i.e., secondary amendment effect). One such amendment in which all 3 types of false-negatives have been observed is with the nonpolar organic amendment (activated carbon or powdered coconut charcoal). The objective of the present study was to reduce the likelihood of encountering false-negatives with this amendment and to increase the value of the whole-sediment TIE bioassay. To do this, the present study evaluated the effects of various activated carbon additions to survival, growth, emergence, and mean development rate of Chironomus tepperi. Using this information, an alternative method for this amendment was developed which utilized a combination of multiple amendment addition ratios based on wet weight (1%, lower likelihood of the secondary amendment effect; 5%, higher reduction of contaminant) and nonconventional endpoints (emergence, mean development rate). This alternative method was then validated in the laboratory (using spiked sediments) and with contaminated field sediments. Using these multiple activated carbon ratios in combination with additional endpoints (namely, emergence) reduced the likelihood of all 3 types of false-negatives and provided a more sensitive evaluation of risk. Environ Toxicol Chem 2018;37:1219-1230. © 2017 SETAC. © 2017 SETAC.

Mercury and selenium accumulation in the Colorado River food web, Grand Canyon, USA

Science.gov (United States)

Walters, David M.; E.J. Rosi-Marshall,; Kennedy, Theodore A.; W.F. Cross,; C.V. Baxter,

2015-01-01

Mercury (Hg) and selenium (Se) biomagnify in aquatic food webs and are toxic to fish and wildlife. The authors measured Hg and Se in organic matter, invertebrates, and fishes in the Colorado River food web at sites spanning 387 river km downstream of Glen Canyon Dam (AZ, USA). Concentrations were relatively high among sites compared with other large rivers (mean wet wt for 6 fishes was 0.17–1.59 μg g–1 Hg and 1.35–2.65 μg g–1 Se), but consistent longitudinal patterns in Hg or Se concentrations relative to the dam were lacking. Mercury increased (slope = 0.147) with δ15N, a metric of trophic position, indicating biomagnification similar to that observed in other freshwater systems. Organisms regularly exceeded exposure risk thresholds for wildlife and humans (6–100% and 56–100% of samples for Hg and Se, respectfully, among risk thresholds). In the Colorado River, Grand Canyon, Hg and Se concentrations pose exposure risks for fish, wildlife, and humans, and the findings of the present study add to a growing body of evidence showing that remote ecosystems are vulnerable to long-range transport and subsequent bioaccumulation of contaminants. Management of exposure risks in Grand Canyon will remain a challenge, as sources and transport mechanisms of Hg and Se extend far beyond park boundaries. Environ Toxicol Chem2015;9999:1–10

Seasonality of dipteran-mediated methylmercury flux from ponds.

Science.gov (United States)

Chumchal, Matthew M; Drenner, Ray W; Hall, MacGregor N; Polk, D Kirkland; Williams, Edward B; Ortega-Rodriguez, Celeste L; Kennedy, James H

2018-03-12

Methylmercury (MeHg) is an aquatic contaminant that can be transferred to terrestrial predators by emergent aquatic insects. We assessed the effects of month and pond permanence on dipteran-mediated MeHg flux (calculated as emergent dipteran biomass × dipteran MeHg concentration) in 10 experimental ponds. Emergent dipterans were collected weekly from permanent ponds with bluegill (Lepomis macrochirus; n = 5) and semipermanent ponds without fish (n = 5) over a 7-mo period (February-August, 2015). We detected a significant effect of month on MeHg flux from 6 dipteran taxa and aggregate MeHg flux, with the highest MeHg flux from herbivorous/detritivorous chironomid midges and predatory midges in March; biting midges, phantom midges and herbivorous/detritivorous orthoclad midges in April; and mosquitoes in August. Aggregate dipteran-mediated MeHg flux peaked in April and then declined throughout the remainder of the summer. We did not detect a significant main effect of pond permanence or a significant month × pond permanence interaction effect on MeHg flux for any of the taxa examined in the present study or for aggregate MeHg flux. Given their ubiquity in aquatic systems and their importance in food webs at the land-water interface, dipterans are important taxa that should not be overlooked as a part of the Hg cycle. Environ Toxicol Chem 2018;9999:1-6. © 2018 SETAC. © 2018 SETAC.

Integrated in silico and in vivo approaches to investigate effects of BDE-99 mediated by the nuclear receptors on developing zebrafish.

Science.gov (United States)

Zhang, Li; Jin, Yaru; Han, Zhihua; Liu, Hongling; Shi, Laihao; Hua, Xiaoxue; Doering, Jon A; Tang, Song; Giesy, John P; Yu, Hongxia

2018-03-01

One of the most abundant polybrominated diphenyl ethers (PBDEs) is 2,2',4,4',5-pentabromodiphenyl ether (BDE-99), which persists and potentially bioaccumulates in aquatic wildlife. Previous studies in mammals have shown that BDE-99 affects development and disrupts certain endocrine functions through signaling pathways mediated by nuclear receptors. However, fewer studies have investigated the potential of BDE-99 to interact with nuclear receptors in aquatic vertebrates such as fish. In the present study, interactions between BDE-99 and nuclear receptors were investigated by in silico and in vivo approaches. This PBDE was able to dock into the ligand-binding domain of zebrafish aryl hydrocarbon receptor 2 (AhR2) and pregnane X receptor (PXR). It had a significant effect on the transcriptional profiles of genes associated with AhR or PXR. Based on the developed cytoscape of all zebrafish genes, it was also inferred that AhR and PXR could interact via cross-talk. In addition, both the in silico and in vivo approaches found that BDE-99 affected peroxisome proliferator-activated receptor alpha (PPARα), glucocorticoid receptor, and thyroid receptor. Collectively, our results demonstrate for the first time detailed in silico evidence that BDE-99 can bind to and interact with zebrafish AhR and PXR. These findings can be used to elaborate the molecular mechanism of BDE-99 and guide more objective environmental risk assessments. Environ Toxicol Chem 2018;37:780-787. © 2017 SETAC. © 2017 SETAC.

Risk assessment of imidacloprid use in forest settings on the aquatic macroinvertebrate community.

Science.gov (United States)

Benton, Elizabeth P; Grant, Jerome F; Nichols, Rebecca J; Webster, R Jesse; Schwartz, John S; Bailey, Joseph K

2017-11-01

The isolated effects of a single insecticide can be difficult to assess in natural settings because of the presence of numerous pollutants in many watersheds. Imidacloprid use for suppressing hemlock woolly adelgid, Adelges tsugae (Annand) (Hemiptera: Adelgidae), in forests offers a rare opportunity to assess potential impacts on aquatic macroinvertebrates in relatively pristine landscapes. Aquatic macroinvertebrate communities were assessed in 9 streams in Great Smoky Mountains National Park (southern Appalachian Mountains, USA). The streams flow through hemlock conservation areas where imidacloprid soil drench treatments were applied for hemlock woolly adelgid suppression. Sites were located upstream and downstream of the imidacloprid treatments. Baseline species presence data (pre-imidacloprid treatment) were available from previous sample collections at downstream sites. Downstream and upstream sites did not vary in numerous community measures. Although comparisons of paired upstream and downstream sites showed differences in diversity in 7 streams, higher diversity was found more often in downstream sites. Macroinvertebrate functional feeding groups and life habits were similar between downstream and upstream sites. Downstream and baseline stream samples were similar. While some functional feeding group and life habit species richness categories varied, variations did not indicate poorer quality downstream communities. Imidacloprid treatments applied according to US Environmental Protection Agency federal restrictions did not result in negative effects to aquatic macroinvertebrate communities, which indicates that risks of imidacloprid use in forest settings are low. Environ Toxicol Chem 2017;36:3108-3119. © 2017 SETAC. © 2017 SETAC.

Transfer of benzo[a]pyrene from microplastics to Artemia nauplii and further to zebrafish via a trophic food web experiment: CYP1A induction and visual tracking of persistent organic pollutants.

Science.gov (United States)

Batel, Annika; Linti, Frederic; Scherer, Martina; Erdinger, Lothar; Braunbeck, Thomas

2016-07-01

The uptake of microplastic particles and the transfer of potential harmful substances along with microplastics has been studied in a variety of organisms, especially invertebrates. However, the potential accumulation of very small microplastic particles along food webs ending with vertebrate models has not been investigated so far. Therefore, a simple artificial food chain with Artemia sp. nauplii and zebrafish (Danio rerio) was established to analyze the transfer of microplastic particles and associated persistent organic pollutants (POPs) between different trophic levels. Very small (1-20 μm) microplastic particles accumulated in Artemia nauplii and were subsequently transferred to fish. Virgin particles not loaded with POPs did not cause any observable physical harm in the intestinal tracts of zebrafish, although parts of the particles were retained within the mucus of intestinal villi and might even have been taken up by epithelial cells. The transfer of associated POPs was tested with the polycyclic aromatic hydrocarbon benzo[a]pyrene and an ethoxyresorufin-O-deethylase (EROD) assay for CYP1A induction in zebrafish liver as well as via fluorescence analyses. Whereas a significant induction in the EROD assay could not be shown, because of high individual variation and low sensitivity regarding substance concentration, the fluorescence tracking of benzo[a]pyrene indicates that food-borne microplastic-associated POPs may actually desorb in the intestine of fish and are thus transferred to the intestinal epithelium and liver. Environ Toxicol Chem 2016;35:1656-1666. © 2016 SETAC. © 2016 SETAC.

Fuel oil and dispersant toxicity to the Antarctic sea urchin (Sterechinus neumayeri).

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Alexander, Frances J; King, Catherine K; Reichelt-Brushett, Amanda J; Harrison, Peter L

2017-06-01

The risk of a major marine fuel spill in Antarctic waters is increasing, yet there are currently no standard or suitable response methods under extreme Antarctic conditions. Fuel dispersants may present a possible solution; however, little data exist on the toxicity of dispersants or fuels to Antarctic species, thereby preventing informed management decisions. Larval development toxicity tests using 3 life history stages of the Antarctic sea urchin (Sterechinus neumayeri) were completed to assess the toxicity of physically dispersed, chemically dispersed, and dispersant-only water-accommodated fractions (WAFs) of an intermediate fuel oil (IFO 180, BP) and the chemical dispersant Slickgone NS (Dasic International). Despite much lower total petroleum hydrocarbon concentrations, physically dispersed fuels contained higher proportions of low-to-intermediate weight carbon compounds and were generally at least an order of magnitude more toxic than chemically dispersed fuels. Based on concentrations that caused 50% abnormality (EC50) values, the embryonic unhatched blastula life stage was the least affected by fuels and dispersants, whereas the larval 4-armed pluteus stage was the most sensitive. The present study is the first to investigate the possible implications of the use of fuel dispersants for fuel spill response in Antarctica. The results indicate that the use of a fuel dispersant did not increase the hydrocarbon toxicity of IFO 180 to the early life stages of Antarctic sea urchins, relative to physical dispersal. Environ Toxicol Chem 2017;36:1563-1571. © 2016 SETAC. © 2016 SETAC.

Ingestion of Bt rice pollen does not reduce the survival or hypopharyngeal gland development of Apis mellifera adults.

Science.gov (United States)

Wang, Yuanyuan; Dai, Pingli; Chen, Xiuping; Romeis, Jörg; Shi, Jianrong; Peng, Yufa; Li, Yunhe

2017-05-01

Because of its ecological and economic importance, the honey bee Apis mellifera is commonly used to assess the environmental risk of insect-resistant, genetically modified plants. In the present study, feeding-exposure experiments were used to determine whether pollen from transgenic rice harms A. mellifera worker bees. In 1 experiment, the survival and mean acinus diameter of hypopharyngeal glands of adult bees were similar when bees were fed on pollen from Bt rice lines or from a non-Bt rice line, but bee survival was significantly reduced when they received pollen that was mixed with potassium arsenate as a positive control. In a second experiment, bee survival and hypopharyngeal gland development were not reduced when adult bees were fed on non-Bt pollen and a sucrose solution supplemented with Cry2A at 400 µg/g, Cry1C at 50 µg/g, or bovine serum albumin (BSA) at 400 µg/g, but bee survival and hypopharyngeal gland development were reduced when the diet was supplemented with soybean trypsin inhibitor as a positive control. In both experiments, the uptake of Cry proteins by adult bees was confirmed. Overall, the results indicate that the planting of Bt rice lines expressing Cry2A or Cry1C protein poses a negligible risk to A. mellifera worker bees. Environ Toxicol Chem 2017;36:1243-1248. © 2016 SETAC. © 2016 SETAC.

In vitro to in vivo extrapolation of biotransformation rates for assessing bioaccumulation of hydrophobic organic chemicals in mammals.

Science.gov (United States)

Lee, Yung-Shan; Lo, Justin C; Otton, S Victoria; Moore, Margo M; Kennedy, Chris J; Gobas, Frank A P C

2017-07-01

Incorporating biotransformation in bioaccumulation assessments of hydrophobic chemicals in both aquatic and terrestrial organisms in a simple, rapid, and cost-effective manner is urgently needed to improve bioaccumulation assessments of potentially bioaccumulative substances. One approach to estimate whole-animal biotransformation rate constants is to combine in vitro measurements of hepatic biotransformation kinetics with in vitro to in vivo extrapolation (IVIVE) and bioaccumulation modeling. An established IVIVE modeling approach exists for pharmaceuticals (referred to in the present study as IVIVE-Ph) and has recently been adapted for chemical bioaccumulation assessments in fish. The present study proposes and tests an alternative IVIVE-B technique to support bioaccumulation assessment of hydrophobic chemicals with a log octanol-water partition coefficient (K OW ) ≥ 4 in mammals. The IVIVE-B approach requires fewer physiological and physiochemical parameters than the IVIVE-Ph approach and does not involve interconversions between clearance and rate constants in the extrapolation. Using in vitro depletion rates, the results show that the IVIVE-B and IVIVE-Ph models yield similar estimates of rat whole-organism biotransformation rate constants for hypothetical chemicals with log K OW  ≥ 4. The IVIVE-B approach generated in vivo biotransformation rate constants and biomagnification factors (BMFs) for benzo[a]pyrene that are within the range of empirical observations. The proposed IVIVE-B technique may be a useful tool for assessing BMFs of hydrophobic organic chemicals in mammals. Environ Toxicol Chem 2017;36:1934-1946. © 2016 SETAC. © 2016 SETAC.

Development of cultures of the marine sponge Hymeniacidon perleve for genotoxicity assessment using the alkaline comet assay.

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Akpiri, Rachael U; Konya, Roseline S; Hodges, Nikolas J

2017-12-01

Sponges are a potential alternative model species to bivalves in pollution biomonitoring and environmental risk assessment in the aquatic ecosystem. In the present study, a novel in vivo exposure sponge culture model was developed from field-collected and cryopreserved sponge (Hymeniacidon perleve) cells to investigate the genotoxic effects of environmentally relevant metals in the laboratory. Sponge cell aggregates were cultured and exposed to noncytotoxic concentrations (0-0.4 mg/L) of cadmium chloride, nickel chloride, and sodium dichromate as quantified by the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and DNA-strand breaks assessed by the comet assay. Reactive oxygen species (ROS) formation was quantified by oxidation of 2',7'-dichlorofluorescin diacetate in sponge cell aggregates exposed to the same concentrations of Cd, Cr, and Ni. There was a statistically significant (p sponge cells and demonstrated that exposure to noncytotoxic concentrations of Cd, Cr, and Ni for 12 h results in a concentration-dependent increase in DNA damage and levels of ROS production. In conclusion, we have developed a novel in vivo model based on culture of cryopreserved sponge cells that is compatible with the alkaline comet assay. Genotoxicity in marine sponges measured by the comet assay technique may be a useful tool for biomonitoring research and risk assessment in aquatic ecosystems. Environ Toxicol Chem 2017;36:3314-3323. © 2017 SETAC. © 2017 SETAC.

Fragment-based approach to calculate hydrophobicity of anionic and nonionic surfactants derived from chromatographic retention on a C18 stationary phase.

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Hammer, Jort; Haftka, Joris J-H; Scherpenisse, Peter; Hermens, Joop L M; de Voogt, Pim W P

2017-02-01

To predict the fate and potential effects of organic contaminants, information about their hydrophobicity is required. However, common parameters to describe the hydrophobicity of organic compounds (e.g., octanol-water partition constant [K OW ]) proved to be inadequate for ionic and nonionic surfactants because of their surface-active properties. As an alternative approach to determine their hydrophobicity, the aim of the present study was therefore to measure the retention of a wide range of surfactants on a C 18 stationary phase. Capacity factors in pure water (k' 0 ) increased linearly with increasing number of carbon atoms in the surfactant structure. Fragment contribution values were determined for each structural unit with multilinear regression, and the results were consistent with the expected influence of these fragments on the hydrophobicity of surfactants. Capacity factors of reference compounds and log K OW values from the literature were used to estimate log K OW values for surfactants (log KOWHPLC). These log KOWHPLC values were also compared to log K OW values calculated with 4 computational programs: KOWWIN, Marvin calculator, SPARC, and COSMOThermX. In conclusion, capacity factors from a C 18 stationary phase are found to better reflect hydrophobicity of surfactants than their K OW values. Environ Toxicol Chem 2017;36:329-336. © 2016 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC. © 2016 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC.

Organ-specific accumulation, transportation, and elimination of methylmercury and inorganic mercury in a low Hg accumulating fish.

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Peng, Xiaoyan; Liu, Fengjie; Wang, Wen-Xiong

2016-08-01

Low mercury (Hg) concentrations down to several nanograms Hg per gram of wet tissue are documented in certain fish species such as herbivorous fish, and the underlying mechanisms remain speculative. In the present study, bioaccumulation and depuration patterns of inorganic Hg(II) and methylmercury (MeHg) in a herbivorous rabbitfish Siganus canaliculatus were investigated at organ and subcellular levels following waterborne or dietary exposures. The results showed that the efflux rate constants of Hg(II) and MeHg were 0.104 d(-1) and 0.024 d(-1) , respectively, and are probably the highest rate constants recorded in fish thus far. The dietary MeHg assimilation efficiency (68%) was much lower than those in other fish species (∼90%). The predominant distribution of MeHg in fish muscle was attributable to negligible elimination of MeHg from muscle (Hg(II) was much more slowly distributed into muscle but was efficiently eliminated by the intestine (0.13 d(-1) ). Subcellular distribution indicated that some specific membrane proteins in muscle were the primary binding pools for MeHg, and both metallothionein-like proteins and Hg-rich granules were the important components in eliminating both MeHg and Hg(II). Overall, the present study's results suggest that the low tissue Hg concentration in the rabbitfish was partly explained by its unique biokinetics. Environ Toxicol Chem 2016;35:2074-2083. © 2016 SETAC. © 2016 SETAC.

Evaluating the effects of triclosan on 3 field crops grown in 4 formulations of biosolids.

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Shahmohamadloo, René S; Lissemore, Linda; Prosser, Ryan S; Sibley, Paul K

2017-07-01

A growing body of evidence suggests that amending soil with biosolids can be an integral component of sustainable agriculture. Despite strong evidence supporting its beneficial use in agriculture, there are concerns that chemicals, such as pharmaceuticals and personal care products, could present a risk to terrestrial ecosystems and human health. Triclosan is one of the most commonly detected compounds in biosolids. To date, laboratory studies indicate that triclosan likely poses a de minimis risk to field crops; however, these studies were either conducted under unrealistic exposure conditions or only assessed 1 or 2 formulations of biosolids. The purpose of the present study was to characterize the effects of triclosan on field crops in soils amended with 4 different formulations of biosolids (liquid, dewatered, compost, and alkaline-hydrolyzed), containing both background and spiked triclosan concentrations, following best management practices used in the province of Ontario. Three crop species (corn, soybean, and spring wheat) were evaluated using several plant growth endpoints (e.g., root wet mass, shoot length, shoot wet/dry mass) in 70-d to 90-d potted soil tests. The results indicated no adverse impact of triclosan on any crop-biosolids combination. Conversely, amending soil with biosolids either enhanced or had no negative effect, on the growth of plants. Results of the present study suggest little risk of triclosan to crops in agricultural fields amended with biosolids. Environ Toxicol Chem 2017;36:1896-1908. © 2016 SETAC. © 2016 SETAC.

Effect of liming on nickel bioavailability and toxicity to oat and soybean grown in field soils containing aged emissions from a nickel refinery.

Science.gov (United States)

Cioccio, Stephen; Gopalapillai, Yamini; Dan, Tereza; Hale, Beverley

2017-04-01

Remediation of soils elevated in trace metals so that the soils may provide ecosystems services is typically achieved through pH adjustment or addition of sorbents. The present study aimed to generate higher-tier in situ toxicity data for elevated nickel (Ni) in soils with and without lime addition and to explore the effect of liming on soil chemistry and bioavailability of Ni to plants. A multiyear study of agronomic yield of field-grown oat and soybean occurred in 3 adjacent fields that had received air emissions from a Ni refinery for 66 yr. The soil Ni concentration in the plots ranged between 1300 mg/kg and 4900 mg/kg, and each field was amended with either 50 Mg/ha, 10 Mg/ha, or 0 Mg/ha (or tonnes/ha) of crushed dolomitic limestone. As expected, liming raised the pH of the soils and subsequently reduced the plant availability of Ni. Toxicity thresholds (effective concentrations causing 50% reduction in growth) for limed soils supported the hypothesis that liming reduces toxicity. Relationships were found between relative yield and soil cation exchange capacity and between relative yield and soil pH, corroborating findings of the European Union Risk Assessments and the Metals in Asia studies, respectively. Higher tier ecotoxicity data such as these are a valuable contribution to risk assessment for Ni in soils. Environ Toxicol Chem 2017;36:1110-1119. © 2016 SETAC. © 2016 SETAC.

Phthalate esters in main source water and drinking water of Zhejiang Province (China): Distribution and health risks.

Science.gov (United States)

Wang, Xiaofeng; Lou, Xiaoming; Zhang, Nianhua; Ding, Gangqiang; Chen, Zhijian; Xu, Peiwei; Wu, Lizhi; Cai, Jianmin; Han, Jianlong; Qiu, Xueting

2015-10-01

To evaluate the distributions and health risks of phthalate esters in the main source water and corresponding drinking water of Zhejiang Province, the concentrations of 16 phthalate esters in water samples from 19 sites were measured from samples taken in the dry season and wet season. The concentration of the total phthalate ester congeners in source water ranged from 1.07 μg/L to 7.12 μg/L in the wet season, from 0.01 μg/L to 1.58 μg/L in the dry season, from 1.18 μg/L to 15.28 μg/L from drinking water in the wet season, and from 0.16 μg/L to 1.86 μg/L from drinking water in the dry season. Of the 16 phthalate esters, dimethyl phthalate, dibutyl phthalate, di-(2-ethyl-hexyl) phthalate, di-iso-butyl phthalate, bis-2-n-butoxyethyl phthalate, and dicyclohexyl phthalate were present in the samples analyzed, dominated by di-iso-butyl phthalate and di-(2-ethyl-hexyl) phthalate. The concentrations of phthalate esters in the wet season were all relatively higher than those in the dry season, and the drinking water had higher concentrations of phthalate esters than source water. The phthalate ester congeners studied pose little health risk to nearby citizens. Environ Toxicol Chem 2015;34:2205-2212. © 2015 SETAC. © 2015 SETAC.

Bioretention storm water control measures decrease the toxicity of copper roof runoff.

Science.gov (United States)

LaBarre, William J; Ownby, David R; Rader, Kevin J; Lev, Steven M; Casey, Ryan E

2017-06-01

The present study evaluated the ability of 2 different bioretention storm water control measures (SCMs), planter boxes and swales, to decrease the toxicity of sheet copper (Cu) roofing runoff to Daphnia magna. The present study quantified changes in storm water chemistry as it passed through the bioretention systems and utilized the biotic ligand model (BLM) to assess whether the observed D. magna toxicity could be predicted by variations found in water chemistry. Laboratory toxicity tests were performed using select storm samples with D. magna cultured under low ionic strength conditions that were appropriate for the low ionic strength of the storm water samples being tested. The SCMs decreased toxicity of Cu roof runoff in both the BLM results and the storm water bioassays. Water exiting the SCMs was substantially higher than influent runoff in pH, ions, alkalinity, and dissolved organic carbon and substantially lower in total and dissolved Cu. Daphnids experienced complete mortality in untreated runoff from the Cu roof (the SCM influent); however, for planter and swale effluents, survival averaged 86% and 95%, respectively. The present study demonstrated that conventional bioretention practices, including planter boxes and swales, are capable of decreasing the risk of adverse effects from sheet Cu roof runoff to receiving systems, even before considering dilution of effluents in those receiving systems and associated further reductions in copper bioavailability. Environ Toxicol Chem 2017;36:1680-1688. © 2016 SETAC. © 2016 SETAC.

Population and life-stage-specific effects of two herbicide formulations on the aquatic development of European common frogs (Rana temporaria).

Science.gov (United States)

Wagner, Norman; Veith, Michael; Lötters, Stefan; Viertel, Bruno

2017-01-01

Environmental contamination is suggested to contribute to amphibian population declines. However, the effects of a contaminant on a particular amphibian species can differ among populations. The authors investigated the toxic effects of 2 herbicide formulations on different populations and on representative developmental stages of the European common frog (Rana temporaria). Larvae from forest populations were more sensitive to a commonly used glyphosate-based herbicide compared with individuals from agrarian land. Median lethal concentrations correlated with measured glyphosate levels in the breeding ponds, which may be a sign of evolved tolerances. The reverse result was observed for a less commonly used cycloxydim-based herbicide. Effects of the glyphosate-based herbicide were stronger for earlier larval stages compared with later larval stages. Hence, applications in early spring (when early larvae are present in breeding ponds) pose greater risk concerning acute toxic effects on R. temporaria. With regard to late larval stages, short exposure (96 h) of prometamorphic larvae prolonged time to metamorphosis, but only at the highest test concentration that did not significantly induce mortality. This could be due to impairment of the thyroid axis. Notably, nearly all test concentrations of the 2 herbicides provoked growth retardation. Further research on how evolved or induced tolerances are acquired, actual contamination levels of amphibian habitats, and potential endocrine effects of glyphosate-based herbicides is necessary. Environ Toxicol Chem 2017;36:190-200. © 2016 SETAC. © 2016 SETAC.

Pollution, toxicity, and ecological risk of heavy metals in surface river sediments of a large basin undergoing rapid economic development.

Science.gov (United States)

Tang, Wenzhong; Zhang, Chao; Zhao, Yu; Shan, Baoqing; Song, Zhixin

2017-05-01

A comprehensive and detailed investigation of heavy metal pollution, toxicity, and ecological risk assessment was conducted for the surface river sediments of the Haihe Basin in China based on 220 sampling sites selected in 2013. The average concentrations of Cr, Cu, Ni, Pb, and Zn in the sediments were 129 mg/kg, 63.4 mg/kg, 36.6 mg/kg, 50.0 mg/kg, and 202 mg/kg, respectively. As indicated by the geoaccumulation and pollution load indices, most surface river sediments of the Haihe Basin were contaminated with the investigated metals, especially in the junction region of the Zi Ya He and Hei Long Gang watersheds. The 5 heavy metals in the sediments all had anthropogenic sources, and the enrichment degrees followed the order Cu > Pb > Zn > Cr > Ni, with mean enrichment factors of 3.27, 2.77, 2.58, 1.81, and 1.44, respectively. According to the mean index of comprehensive potential ecological risk (38.9), the studied sediments of the Haihe Basin showed low potential ecological risk, but the sediments were potentially biologically toxic based on the mean probable effect concentration quotient (0.547), which may be the result of speciation of the 5 metals in the sediments. The results indicate that heavy metal pollution should be considered during the development of ecological restoration strategies in the Haihe Basin. Environ Toxicol Chem 2017;36:1149-1155. © 2016 SETAC. © 2016 SETAC.

Determining octanol-water partition coefficients for extremely hydrophobic chemicals by combining "slow stirring" and solid-phase microextraction.

Science.gov (United States)

Jonker, Michiel T O

2016-06-01

Octanol-water partition coefficients (KOW ) are widely used in fate and effects modeling of chemicals. Still, high-quality experimental KOW data are scarce, in particular for very hydrophobic chemicals. This hampers reliable assessments of several fate and effect parameters and the development and validation of new models. One reason for the limited availability of experimental values may relate to the challenging nature of KOW measurements. In the present study, KOW values for 13 polycyclic aromatic hydrocarbons were determined with the gold standard "slow-stirring" method (log KOW 4.6-7.2). These values were then used as reference data for the development of an alternative method for measuring KOW . This approach combined slow stirring and equilibrium sampling of the extremely low aqueous concentrations with polydimethylsiloxane-coated solid-phase microextraction fibers, applying experimentally determined fiber-water partition coefficients. It resulted in KOW values matching the slow-stirring data very well. Therefore, the method was subsequently applied to a series of 17 moderately to extremely hydrophobic petrochemical compounds. The obtained KOW values spanned almost 6 orders of magnitude, with the highest value measuring 10(10.6) . The present study demonstrates that the hydrophobicity domain within which experimental KOW measurements are possible can be extended with the help of solid-phase microextraction and that experimentally determined KOW values can exceed the proposed upper limit of 10(9) . Environ Toxicol Chem 2016;35:1371-1377. © 2015 SETAC. © 2015 SETAC.

Chronic toxicity of selected polycyclic aromatic hydrocarbons to algae and crustaceans using passive dosing.

Science.gov (United States)

Bragin, Gail E; Parkerton, Thomas F; Redman, Aaron D; Letinksi, Daniel J; Butler, Josh D; Paumen, Miriam Leon; Sutherland, Cary A; Knarr, Tricia M; Comber, Mike; den Haan, Klaas

2016-12-01

Because of the large number of possible aromatic hydrocarbon structures, predictive toxicity models are needed to support substance hazard and risk assessments. Calibration and evaluation of such models requires toxicity data with well-defined exposures. The present study has applied a passive dosing method to generate reliable chronic effects data for 8 polycyclic aromatic hydrocarbons (PAHs) on the green algae Pseudokirchneriella subcapitata and the crustacean Ceriodaphnia dubia. The observed toxicity of these substances on algal growth rate and neonate production were then compared with available literature toxicity data for these species, as well as target lipid model and chemical activity-based model predictions. The use of passive dosing provided well-controlled exposures that yielded more consistent data sets than attained by past literature studies. Results from the present study, which were designed to exclude the complicating influence of ultraviolet light, were found to be well described by both target lipid model and chemical activity effect models. The present study also found that the lack of chronic effects for high molecular weight PAHs was consistent with the limited chemical activity that could be achieved for these compounds in the aqueous test media. Findings from this analysis highlight that variability in past literature toxicity data for PAHs may be complicated by both poorly controlled exposures and photochemical processes that can modulate both exposure and toxicity. Environ Toxicol Chem 2016;35:2948-2957. © 2016 SETAC. © 2016 SETAC.

Immunotoxicity in green mussels under perfluoroalkyl substance (PFAS) exposure: Reversible response and response model development.

Science.gov (United States)

Liu, Changhui; Gin, Karina Yew-Hoong

2018-04-01

The immunotoxicity of 4 commonly detected perfluoroalkyl substances (PFASs), namely, perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) was investigated by measuring biomarkers of the immune profile of green mussels, Perna viridis. The biomarkers included neutral red retention, phagocytosis, and spontaneous cytotoxicity, all of which were tested on mussel hemocytes. Hemocytes are an important component of the invertebrate immune system. We found that exposure to PFASs could lead to reduced hemocyte cell viability and suppress immune function by up to 50% of normal performance within the experimental exposure range. The results indicate that PFASs have an immunotoxic potential and thus could pose severe health risks to aquatic organisms. The reported immunotoxicity is likely to result from the compounds' direct and indirect interactions with the hemocyte membrane, and therefore likely to affect the functionality of these cells. The immunotoxic response was found to be related to the organism's burden of PFASs, and was reversible when the compounds were removed from the test organisms. Based on this relationship, models using an organism's PFAS concentration and bioaccumulation factor (BAF) as the independent variables were established to quantify PFAS-induced immunotoxicity. The models help us to gain a better understanding of the toxic mechanism of PFASs, and provide a tool to evaluate adverse effects for the whole group of compounds with one mathematical equation. Environ Toxicol Chem 2018;37:1138-1145. © 2018 SETAC. © 2018 SETAC.

Alleviation of environmental risks associated with severely contaminated mine tailings using amendments: Modeling of trace element speciation, solubility, and plant accumulation.

Science.gov (United States)

Pardo, Tania; Bes, Cleménce; Bernal, Maria Pilar; Clemente, Rafael

2016-11-01

Tailings are considered one of the most relevant sources of contamination associated with mining activities. Phytostabilization of mine spoils may need the application of the adequate combination of amendments to facilitate plant establishment and reduce their environmental impact. Two pot experiments were set up to assess the capability of 2 inorganic materials (calcium carbonate and a red mud derivate, ViroBind TM ), alone or in combination with organic amendments, for the stabilization of highly acidic trace element-contaminated mine tailings using Atriplex halimus. The effects of the treatments on tailings and porewater physico-chemical properties and trace-element accumulation by the plants, as well as the processes governing trace elements speciation and solubility in soil solution and their bioavailability were modeled. The application of the amendments increased tailings pH and decreased (>99%) trace elements solubility in porewater, but also changed the speciation of soluble Cd, Cu, and Pb. All the treatments made A. halimus growth in the tailings possible; organic amendments increased plant biomass and nutritional status, and reduced trace-element accumulation in the plants. Tailings amendments modified trace-element speciation in porewater (favoring the formation of chlorides and/or organo-metallic forms) and their solubility and plant uptake, which were found to be mainly governed by tailing/porewater pH, electrical conductivity, and organic carbon content, as well as soluble/available trace-element concentrations. Environ Toxicol Chem 2016;35:2874-2884. © 2016 SETAC. © 2016 SETAC.

Model tool to describe chemical structures in XML format utilizing structural fragments and chemical ontology.

Science.gov (United States)

Sankar, Punnaivanam; Alain, Krief; Aghila, Gnanasekaran

2010-05-24

We have developed a model structure-editing tool, ChemEd, programmed in JAVA, which allows drawing chemical structures on a graphical user interface (GUI) by selecting appropriate structural fragments defined in a fragment library. The terms representing the structural fragments are organized in fragment ontology to provide a conceptual support. ChemEd describes the chemical structure in an XML document (ChemFul) with rich semantics explicitly encoding the details of the chemical bonding, the hybridization status, and the electron environment around each atom. The document can be further processed through suitable algorithms and with the support of external chemical ontologies to generate understandable reports about the functional groups present in the structure and their specific environment.

Toxicological aspects and occurrence of patulin in apple juice/ Aspectos toxicológicos e ocorrência de patulina em suco de maçã

Directory of Open Access Journals (Sweden)

Miguel Machinski Junior

2005-06-01

Full Text Available Patulin is a secondary metabolite produced by different species of fungi, being Penicillium expansum the most important species. Patulin is a mycotoxin that has been found mainly in mature apples used in the production of concentrated apple juice, but it can also be in other fruits, vegetables and nutritious products. Experiments carried out with laboratory animals have demonstrated that this mycotoxin produces several harmful effects, including mutagenicity, teratogenicity, carcinogenicity, immunosuppression and acute intoxications characterized by pulmonary oedema, hemorrhages, damages in the capillaries of liver, spleen and kidneys, as well as cerebral oedema. This revision article approaches physicochemical properties and toxicological aspects of the patulin, as well as its occurrence and strategies to prevent its presence in apple juices.A patulina é um metabólito secundário produzido por diferentes gêneros e espécies de fungos. Penicillium expansum é certamente a espécie mais importante. É uma micotoxina encontrada principalmente em maçãs maduras utilizadas na produção de suco de maçã concentrado, mas também pode estar presente em outras frutas, vegetais e produtos alimentícios. Experimentos em animais de laboratório demonstraram que esta micotoxina produz diversos efeitos nocivos, incluindo mutagenicidade, teratogenicidade, carcinogenicidade, imunossupressão e intoxicações agudas caracterizadas por edema pulmonar, hemorragias, danos nos capilares hepáticos, do baço e rins, bem como edema cerebral. O presente artigo de revisão aborda aspectos físico-químicos e toxicológicos da patulina, bem como a sua ocorrência e estratégias para prevenir a sua presença em sucos de maçã.

Sensitivity of simulated convection-driven stratosphere-troposphere exchange in WRF-Chem to the choice of physical and chemical parameterization

Science.gov (United States)

Phoenix, Daniel B.; Homeyer, Cameron R.; Barth, Mary C.

2017-08-01

Tropopause-penetrating convection is capable of rapidly transporting air from the lower troposphere to the upper troposphere and lower stratosphere (UTLS), where it can have important impacts on chemistry, the radiative budget, and climate. However, obtaining in situ measurements of convection and convective transport is difficult and such observations are historically rare. Modeling studies, on the other hand, offer the advantage of providing output related to the physical, dynamical, and chemical characteristics of storms and their environments at fine spatial and temporal scales. Since these characteristics of simulated convection depend on the chosen model design, we examine the sensitivity of simulated convective transport to the choice of physical (bulk microphysics or BMP and planetary boundary layer or PBL) and chemical parameterizations in the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem). In particular, we simulate multiple cases where in situ observations are available from the recent (2012) Deep Convective Clouds and Chemistry (DC3) experiment. Model output is evaluated using ground-based radar observations of each storm and in situ trace gas observations from two aircraft operated during the DC3 experiment. Model results show measurable sensitivity of the physical characteristics of a storm and the transport of water vapor and additional trace gases into the UTLS to the choice of BMP. The physical characteristics of the storm and transport of insoluble trace gases are largely insensitive to the choice of PBL scheme and chemical mechanism, though several soluble trace gases (e.g., SO2, CH2O, and HNO3) exhibit some measurable sensitivity.

Photochemical Pollution Modeling of Ozone at Metropolitan Area of Porto Alegre - RS/Brazil using WRF/Chem

Science.gov (United States)

Cuchiara, G. C.; Carvalho, J.

2013-05-01

One of the main problems related to air pollution in urban areas is caused by photochemical oxidants, particularly troposphere ozone (O3), which is considered a harmful substance. The O3 precursors (carbon monoxide CO, nitrogen oxides NOx and hydrocarbons HCs) are predominantly of anthropogenic origin in these areas, and vehicles are the main emission sources. Due to the increased urbanization and industrial development in recent decades, air pollutant emissions have increased likewise, mainly by mobile sources in the highly urbanized and developed areas, such as the Metropolitan Area of Porto Alegre-RS (MAPA). According to legal regulations implemented in Brazil in 2005, which aimed at increasing the fraction of biofuels in the national energy matrix, 2% biodiesel were supposed to be added to the fuel mixture within three years, and up to 5% after eight years of implementation of these regulations. Our work performs an analysis of surface concentrations for O3, NOx, CO, and HCs through numerical simulations with WRF/Chem (Weather Research and Forecasting model with Chemistry). The model is validated against observational data obtained from the local urban air quality network for the period from January 5 to 9, 2009 (96 hours). One part of the study focused on the comparison of simulated meteorological variables, to observational data from two stations in MAPA. The results showed that the model simulates well the diurnal evolution of pressure and temperature at the surface, but is much less accurate for wind speed. Another part included the evaluation of model results of WRF/Chem for O3 versus observed data at air quality stations Esteio and Porto Alegre. Comparisons between simulated and observed O3 revealed that the model simulates well the evolution of the observed values, but on many occasions the model did not reproduce well the maximum and minimum concentrations. Finally, a preliminary quantitative sensitivity study on the impact of biofuel on the

Investigating organic aerosol loading in the remote marine environment

Directory of Open Access Journals (Sweden)

K. Lapina

2011-09-01

Full Text Available Aerosol loading in the marine environment is investigated using aerosol composition measurements from several research ship campaigns (ICEALOT, MAP, RHaMBLe, VOCALS and OOMPH, observations of total AOD column from satellite (MODIS and ship-based instruments (Maritime Aerosol Network, MAN, and a global chemical transport model (GEOS-Chem. This work represents the most comprehensive evaluation of oceanic OM emission inventories to date, by employing aerosol composition measurements obtained from campaigns with wide spatial and temporal coverage. The model underestimates AOD over the remote ocean on average by 0.02 (21 %, compared to satellite observations, but provides an unbiased simulation of ground-based Maritime Aerosol Network (MAN observations. Comparison with cruise data demonstrates that the GEOS-Chem simulation of marine sulfate, with the mean observed values ranging between 0.22 μg m⁻³ and 1.34 μg m⁻³, is generally unbiased, however surface organic matter (OM concentrations, with the mean observed concentrations between 0.07 μg m⁻³ and 0.77 μg m⁻³, are underestimated by a factor of 2–5 for the standard model run. Addition of a sub-micron marine OM source of approximately 9 TgC yr⁻¹ brings the model into agreement with the ship-based measurements, however this additional OM source does not explain the model underestimate of marine AOD. The model underestimate of marine AOD is therefore likely the result of a combination of satellite retrieval bias and a missing marine aerosol source (which exhibits a different spatial pattern than existing aerosol in the model.

Flow-covariate prediction of stream pesticide concentrations.

Science.gov (United States)

Mosquin, Paul L; Aldworth, Jeremy; Chen, Wenlin

2018-01-01

Potential peak functions (e.g., maximum rolling averages over a given duration) of annual pesticide concentrations in the aquatic environment are important exposure parameters (or target quantities) for ecological risk assessments. These target quantities require accurate concentration estimates on nonsampled days in a monitoring program. We examined stream flow as a covariate via universal kriging to improve predictions of maximum m-day (m = 1, 7, 14, 30, 60) rolling averages and the 95th percentiles of atrazine concentration in streams where data were collected every 7 or 14 d. The universal kriging predictions were evaluated against the target quantities calculated directly from the daily (or near daily) measured atrazine concentration at 32 sites (89 site-yr) as part of the Atrazine Ecological Monitoring Program in the US corn belt region (2008-2013) and 4 sites (62 site-yr) in Ohio by the National Center for Water Quality Research (1993-2008). Because stream flow data are strongly skewed to the right, 3 transformations of the flow covariate were considered: log transformation, short-term flow anomaly, and normalized Box-Cox transformation. The normalized Box-Cox transformation resulted in predictions of the target quantities that were comparable to those obtained from log-linear interpolation (i.e., linear interpolation on the log scale) for 7-d sampling. However, the predictions appeared to be negatively affected by variability in regression coefficient estimates across different sample realizations of the concentration time series. Therefore, revised models incorporating seasonal covariates and partially or fully constrained regression parameters were investigated, and they were found to provide much improved predictions in comparison with those from log-linear interpolation for all rolling average measures. Environ Toxicol Chem 2018;37:260-273. © 2017 SETAC. © 2017 SETAC.

Summary of the development the US Environmental Protection Agency's Medaka Extended One Generation Reproduction Test (MEOGRT) using data from 9 multigenerational medaka tests.

Science.gov (United States)

Flynn, Kevin; Lothenbach, Doug; Whiteman, Frank; Hammermeister, Dean; Touart, Leslie W; Swintek, Joe; Tatarazako, Norihisa; Onishi, Yuta; Iguchi, Taisen; Johnson, Rodney

2017-12-01

In response to various legislative mandates, the US Environmental Protection Agency (USEPA) formed its Endocrine Disruptor Screening Program (EDSP), which in turn, formed the basis of a tiered testing strategy to determine the potential of pesticides, commercial chemicals, and environmental contaminants to disrupt the endocrine system. The first tier of tests is intended to detect the potential for endocrine disruption mediated through estrogen, androgen, or thyroid pathways, whereas the second tier is intended to further characterize the effects on these pathways and to establish a dose-response relationship for adverse effects. One of these tier 2 tests, the Medaka Extended One Generation Reproduction Test (MEOGRT), was developed by the USEPA for the EDSP and, in collaboration with the Japanese Ministry of the Environment, for the Guidelines for the Testing of Chemicals of the Organisation for Economic Co-operation and Development (OECD). The MEOGRT protocol was iteratively modified based on knowledge gained after the successful completion of 9 tests with variations in test protocols. The present study describes both the final MEOGRT protocol that has been published by the USEPA and the OECD, and the iterations that provided valuable insights into nuances of the protocol. The various tests include exposure to 17β-estradiol, 4-t-octylphenol, o,p'- dichlorodiphenyltrichloroethane, 4-chloro-3-methylphenol, tamoxifen, 17β-trenbolone, vinclozolin, and prochloraz. Environ Toxicol Chem 2017;36:3387-3403. Published 2017 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2017 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Factors influencing the toxicity of Headline® fungicides to terrestrial stage toads.

Science.gov (United States)

Cusaac, J Patrick W; Mimbs, William H; Belden, Jason B; Smith, Loren M; McMurry, Scott T

2017-10-01

Amphibians are susceptible to exposure from contaminants via multiple pathways. Pyraclostrobin fungicides have been shown to be toxic to terrestrial amphibians at environmentally relevant concentrations; however, these studies did not account for factors that may influence exposure and effects, such as fungicide formulation, age of the individual, exposure route, and physiological state of the individual. We examined Headline® and Headline AMP® fungicide toxicity to adult Anaxyrus cognatus and Anaxyrus woodhousii by direct overspray, as well as acute toxicity of Headline AMP to juvenile A. cognatus through direct overspray, previously exposed soils, and diet. We also assessed effects of hydration state on fungicide toxicity in juvenile A. cognatus and sublethal effects of fungicide exposure on prey-orientation ability of juvenile A. cognatus. Neither formulation of Headline caused mortality of adult A. cognatus and A. woodhousii at up to 5 times the maximum label rate in North American corn (1052 and 879 mL formulation/ha for Headline AMP and Headline fungicides, respectively, corresponding to 1.52 and 2.2 μg pyraclostrobin/cm 2 , respectively). Exposures of juvenile A. cognatus to Headline AMP via direct overspray and previously exposed soils (2 types) resulted in median lethal rate (LR50) values of 2.4, 3.34, and 3.61 μg pyraclostrobin/cm 2 , respectively. Dietary Headline AMP exposure was not toxic, prey-orientations were not influenced by exposure, and effects were similar between dehydrated and hydrated treatments (LR50 = 2.4 and 2.3 μg pyraclostrobin/cm 2 , respectively). These results, combined with exposure concentrations reported in previous studies, suggest that risk of acute mortality for amphibians in terrestrial environments is low and is dictated by body size and site-specific factors influencing exposure. Environ Toxicol Chem 2017;36:2679-2688. © 2017 SETAC. © 2017 SETAC.

Modelling Poly-Aromatic Hydrocarbons "online" with the GEOS-Chem Europe and Asia regional models.

Science.gov (United States)

Ivatt, P.; Evans, M. J.

2017-12-01

Poly-Aromatic Hydrocarbons (PAHs) are carcinogens and so are restricted by international treaties. PAHs are mainly emitted into the atmosphere by domestic (heating and cooking), natural (forest fires burning), as well as some industrial processes (coke ovens). PAHs partition between the gas and particle phase (notably carbonaceous particles) based on their volatility. In recent years, interest has turned to the possible health effects of their oxidation products (both nitrogenated and oxygenated) as it has been suggested that these oxidation products may be even more carcinogenic than the parent PAHs. To increase our understanding of the processes controlling the regional concentrations of PAHs and their oxidation products an "online" PAH model has been developed within the GEOS-Chem framework. This provides for the representation of the coupled aerosol/gas phase chemistry of the parent PAH and its secondary oxidation products. Benzo[a]pyrene is used as an exemplar but the methodology is flexible and the approach can be used for any PAH species. Comparisons are made with observations and the sources of variability discussed.

Harmonização e classificação toxicológica de agrotóxicos em 1992 no Brasil e a necessidade de prever os impactos da futura implantação do GHS Harmonization and toxicological classification of pesticides in 1992 in Brazil and the need to foresee the impacts from the forthcoming introduction of GHS

Directory of Open Access Journals (Sweden)

Eduardo Garcia Garcia

2008-12-01

Full Text Available Em 1992, o Brasil modificou seus critérios de classificação toxicológica de agrotóxicos adequando-os à recomendação de classificação de periculosidade da Organização Mundial da Saúde (OMS. Em 2002, o Sistema Globalmente Harmonizado de Classificação e Rotulagem de Produtos Químicos (GHS foi adotado pela Organização das Nações Unidas. Em decorrência, a OMS está adequando ao GHS sua recomendação de classificação de agrotóxicos, o que também deverá ser feito pelo Brasil. Considerou-se oportuno estimar o impacto da alteração de critérios, ocorrida em 1992, na reclassificação toxicológica dos produtos comerciais que se encontravam registrados na ocasião. Encontrou-se que 58,6% do total dos agrotóxicos então registrados (74,9% das formulações líquidas e 31,0% das sólidas podem ter sofrido reclassificação para classes toxicológicas consideradas de me-nor periculosidade, sofrendo mudanças na comunicação de riscos expressa na rotulagem. Isto pode ter ocasionado conseqüências negativas devido a confusões de interpretação pelos agricultores. Nos países que já dispõem de sistemas de classificação de periculosidade de agrotóxicos, como o Brasil, recomenda-se estimar, antes da implantação, os impactos das mudanças que poderão decorrer da adoção do GHS.In 1992, Brazil modified its toxicological classification criteria for pesticides. This modification aimed to follow the guidelines of the World Health Organization (WHO hazard classification of pesticides. In 2002, the United Nations adopted the "Globally Harmonized System for the Classification and Labelling of Chemicals" (GHS. As a result, the WHO is reviewing its classification and Brazil will probably follow the example. Therefore it seems timely to estimate the impact of the changes in the criteria adopted in 1992 in the toxicological reclassification and labelling of the commercially available products registered at that time. It is estimated

Mixed waste treatment using the ChemChar thermolytic detoxification technique

Energy Technology Data Exchange (ETDEWEB)

Kuchynka, D.

1995-12-31

The diversity of mixed waste matrices contained at Department of Energy sites that require treatment preclude a single, universal treatment technology capable of handling sludges, solids, heterogeneous debris, aqueous and organic liquids and soils. Versatility of the treatment technology, volume reduction and containment of the radioactive component of the mixed waste streams are three criteria to be considered when evaluating potential treatment technologies. The ChemChar thermolytic detoxification process being developed under this R and D contract is a thermal, chemically reductive technology that converts the organic portion of a mixed waste stream to an energy-rich synthesis gas while simultaneously absorbing volatile inorganic species (metals and acid gases) on a macroporous, carbon-based char. The latter is mixed with the waste stream prior to entering the reactor. Substoichiometric amounts of oxidant are fed into the top portion of the cylindrical reactor generating a thin, radial thermochemical reaction zone. This zone generates all the necessary heat to promote the highly endothermic reduction of the organic components in the waste in the lower portion of the reactor, producing, principally, hydrogen and carbon monoxide. The solid by-product is a regenerated carbon char that, depending on the inorganic loading, is capable for reuse. The in situ scrubbing of contaminants by the char within the reactor coupled with a char filter for final polishing produce an exceptionally clean synthesis gas effluent suitable for on-site generation of heat, steam or electricity. Despite the elevated temperatures in the thermochemical reaction zone, the reductive nature of the process precludes formation of nitrogen oxides and halogenated organic compound by-products.

Mixed waste treatment using the ChemChar thermolytic detoxification technique

International Nuclear Information System (INIS)

Kuchynka, D.

1995-01-01

The diversity of mixed waste matrices contained at Department of Energy sites that require treatment preclude a single, universal treatment technology capable of handling sludges, solids, heterogeneous debris, aqueous and organic liquids and soils. Versatility of the treatment technology, volume reduction and containment of the radioactive component of the mixed waste streams are three criteria to be considered when evaluating potential treatment technologies. The ChemChar thermolytic detoxification process being developed under this R and D contract is a thermal, chemically reductive technology that converts the organic portion of a mixed waste stream to an energy-rich synthesis gas while simultaneously absorbing volatile inorganic species (metals and acid gases) on a macroporous, carbon-based char. The latter is mixed with the waste stream prior to entering the reactor. Substoichiometric amounts of oxidant are fed into the top portion of the cylindrical reactor generating a thin, radial thermochemical reaction zone. This zone generates all the necessary heat to promote the highly endothermic reduction of the organic components in the waste in the lower portion of the reactor, producing, principally, hydrogen and carbon monoxide. The solid by-product is a regenerated carbon char that, depending on the inorganic loading, is capable for reuse. The in situ scrubbing of contaminants by the char within the reactor coupled with a char filter for final polishing produce an exceptionally clean synthesis gas effluent suitable for on-site generation of heat, steam or electricity. Despite the elevated temperatures in the thermochemical reaction zone, the reductive nature of the process precludes formation of nitrogen oxides and halogenated organic compound by-products

Comparison of Predicted pKa Values for Some Amino-Acids, Dipeptides and Tripeptides, Using COSMO-RS, ChemAxon and ACD/Labs Methods Comparaison des valeurs de pKa de quelques acides aminés, dipeptides et tripeptides, prédites en utilisant les méthodes COSMO-RS, ChemAxon et ACD/Labs

Directory of Open Access Journals (Sweden)

Toure O.

2013-05-01

as peptides. The final goal of this study is to use the pKa values in a predictive thermodynamics model for products of interest in food industry. For this purpose, the effects of several factors (like conformations set treatment in COSMO-RS calculations, ionic strength effect that can affect the comparison between observed and predicted pKa data are discussed. Les valeurs de constantes d’acidité (pKa jouent un rôle très important, en particulier dans l’industrie alimentaire. Les propriétés chimiques des molécules dépendent significativement de leurs états d’ionisation. La plupart des molécules sont capables de gagner et/ou perdre un proton dans les solutions aqueuses. Ce transfert de proton apparaît la plupart du temps entre l’eau et un atome ionisable de la molécule organique. La réponse de la molécule à la protonation ou à la déprotonation dépend significativement du site concerné par le transfert de proton. La distribution partielle des charges dans la molécule varie également en fonction des sites actifs pour la protonation du couple acide; base. Par conséquent on peut l’utiliser pour déterminer le pKa d’une molécule. Dans un premier temps, nous avons utilisé la méthode COSMO-RS, une combinaison du modèle de solvatation diélectrique (COSMO et d’un traitement de thermodynamique statistique pour des solvants plus réels (RS, pour prédire les constantes de dissociation de 50 molécules environ (des acides aminés, des dipeptides et des tripeptides. Les résultats de pKa obtenus ont été comparés aux valeurs expérimentales, ainsi qu’aux valeurs de pKa prédites par deux autres méthodes. Nous avons utilisé respectivement la méthode ChemAxon, utilisant un programme basé sur le calcul des charges partielles des atomes d’une molécule, et la méthode ACD/Labs qui permet de déterminer des valeurs de pKa pour chaque centre de dissociation en considérant que le reste de la molécule est neutre, en utilisant une base de

The EnVision++ system: a new immunohistochemical method for diagnostics and research. Critical comparison with the APAAP, ChemMate, CSA, LABC, and SABC techniques.

Science.gov (United States)

Sabattini, E; Bisgaard, K; Ascani, S; Poggi, S; Piccioli, M; Ceccarelli, C; Pieri, F; Fraternali-Orcioni, G; Pileri, S A

1998-07-01

To assess a newly developed immunohistochemical detection system, the EnVision++. A large series of differently processed normal and pathological samples and 53 relevant monoclonal antibodies were chosen. A chessboard titration assay was used to compare the results provided by the EnVision++ system with those of the APAAP, CSA, LSAB, SABC, and ChemMate methods, when applied either manually or in a TechMate 500 immunostainer. With the vast majority of the antibodies, EnVision++ allowed two- to fivefold higher dilutions than the APAAP, LSAB, SABC, and ChemMate techniques, the staining intensity and percentage of expected positive cells being the same. With some critical antibodies (such as the anti-CD5), it turned out to be superior in that it achieved consistently reproducible results with differently fixed or overfixed samples. Only the CSA method, which includes tyramide based enhancement, allowed the same dilutions as the EnVision++ system, and in one instance (with the anti-cyclin D1 antibody) represented the gold standard. The EnVision++ is an easy to use system, which avoids the possibility of disturbing endogenous biotin and lowers the cost per test by increasing the dilutions of the primary antibodies. Being a two step procedure, it reduces both the assay time and the workload.

Laser induced breakdown spectroscopy library for the Martian environment

International Nuclear Information System (INIS)

Cousin, A.; Forni, O.; Maurice, S.; Gasnault, O.

2011-01-01

The NASA Mars Science Laboratory rover will carry the first Laser Induced Breakdown Spectroscopy experiment in space: ChemCam. We have developed a laboratory model which mimics ChemCam's main characteristics. We used a set of target samples relevant to Mars geochemistry, and we recorded individual spectra. We propose a data reduction scheme for Laser Induced Breakdown Spectroscopy data incorporating de-noising, continuum removal, and peak fitting. Known effects of the Martian atmosphere are confirmed with our experiment: better Signal-to-Noise Ratio on Mars compared to Earth, narrower peak width, and essentially no self-absorption. The wavelength shift of emission lines from air to Mars pressure is discussed. The National Institute of Standards and Technology vacuum database is used for wavelength calibration and to identify the elemental lines. Our Martian database contains 1336 lines for 32 elements: H, Li, Be, B, C, N, O, F, Na, Mg, Al, Si, P, S, Cl, K, Ar, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Rb, Sr, Cs, Ba, and Pb. It is a subset of the National Institute of Standards and Technology database to be used for Martian geochemistry. Finally, synthetic spectra can be built from the Martian database. Correlation calculations help to distinguish between elements in case of uncertainty. This work is used to create tools and support data for the interpretation of ChemCam results. - Highlights: ► Chemcam: first Laser Induced Breakdown Spectroscopy technique on Mars. ► Creation of a LIBS specific database to ChemCam on Mars. ► Data reduction scheme is proposed. ► Best signal under Martian conditions. ► LIBS emission lines database: subset of NIST database for Martian geochemistry.

Recovery from reproductive and morphological abnormalities in medaka (Oryzias latipes) following a 14-day exposure to diclofenac.

Science.gov (United States)

Yokota, Hirofumi; Higashi, Kaho; Hanada, Erina; Matsuzaki, Ei; Tsuruda, Yukinari; Suzuki, Tomoko; Nakano, Eiko; Eguchi, Sayaka

2017-12-01

Mating pairs of medaka (Oryzias latipes) were exposed to diclofenac at measured concentrations of 0 (control), 7.1, 37, and 78 μg/L for 14 d under static-renewal conditions. Effects on reproductive success, as well as morphological abnormalities, of the fish were assessed. During the exposure period, both fecundity and fertility were significantly decreased in the 37- and 78-μg/L treatment groups, and swollen abdomens in females were observed in all exposure groups. Notably, a defect of the lower jaw was also observed in 4 male fish: 2 at 37 μg/L and 2 at 78 μg/L of diclofenac. Subsequently, we investigated whether the reproductive and morphological abnormalities induced by diclofenac would be permanent or reversible once the medaka were returned to clean water. The reproductive ability of paired medaka was gradually restored to fish that were cultured in clean water for 14 d. After this period in clean water, we also observed a noticeable decrease in swollen abdomens in females; however, mandibular defects in the males remained, even after the 14-d recovery period. Radiographic and histochemical examinations revealed that diclofenac might affect bone remodeling in the lower jaw of male medaka because of a disruption in osteoclast function. These results suggest that reproductive impairments in pairs of medaka exposed to diclofenac may be reversible but that skeletal deformities (i.e., mandibular defect) in males may be persistent. Environ Toxicol Chem 2017;36:3277-3283. © 2017 SETAC. © 2017 SETAC.

Seasonality of odonate-mediated methylmercury flux from permanent and semipermanent ponds and potential risk to red-winged blackbirds (Agelaius phoeniceus).

Science.gov (United States)

Williams, Edward B; Chumchal, Matthew M; Drenner, Ray W; Kennedy, James H

2017-10-01

Methylmercury (MeHg) is an aquatic contaminant that can be transferred to terrestrial predators by emergent aquatic insects such as odonates (damselflies and dragonflies). We assessed the effects of month and pond permanence on odonate-mediated MeHg flux (calculated as emergent odonate biomass × MeHg concentration) in 10 experimental ponds and the potential risk to nestling red-winged blackbirds (Agelaius phoeniceus) posed by consuming MeHg-contaminated odonates. Emergent odonates were collected weekly from permanent ponds with bluegill (Lepomis macrochirus; n = 5) and semipermanent ponds without fish (n = 5) over an 8-mo period (January-August 2015). The MeHg flux from damselflies, aeshnid dragonflies, and libellulid dragonflies began in March and peaked in April, May, and June, respectively, and then declined throughout the rest of the summer. Odonate-mediated MeHg flux from semipermanent ponds without fish was greater than that from permanent ponds with fish. Nesting of red-winged blackbirds overlapped with peak odonate emergence and odonate-mediated MeHg flux. Because their diet can be dominated by damselflies and dragonflies, we tested the hypothesis that MeHg-contaminated odonates may pose a health risk to nestling red-winged blackbirds. Concentrations of MeHg in odonates exceeded wildlife values (the minimum odonate MeHg concentrations causing physiologically significant doses in consumers) for nestlings, suggesting that MeHg-contaminated odonates can pose a health risk to nestling red-winged blackbirds. Environ Toxicol Chem 2017;36:2833-2837. © 2017 SETAC. © 2017 SETAC.

Assessing the toxicity of sediments using the medaka embryo-larval assay and 2 other bioassays.

Science.gov (United States)

Barhoumi, Badreddine; Clérandeau, Christelle; Landi, Laure; Pichon, Anaïk; Le Bihanic, Florane; Poirier, Dominique; Anschutz, Pierre; Budzinski, Hélène; Driss, Mohamed Ridha; Cachot, Jérôme

2016-09-01

Sediments are sinks for aquatic pollutants, and analyzing toxicity in such complex matrices is still challenging. To evaluate the toxicity of bioavailable pollutants accumulated in sediments from the Bizerte lagoon (Tunisia), a novel assay, the medaka embryo-larval assay by sediment contact, was applied. Japanese medaka (Oryzias latipes) embryos were incubated in direct contact with sediment samples up to hatching. Lethal and sublethal adverse effects were recorded in embryos and larvae up to 20 d postfertilization. Results from medaka embryo-larval assay were compared with cytotoxicity (Microtox®), genotoxicity (SOS chromotest), and pollutant content of sediments. The results highlight differences in the contamination profile and toxicity pattern between the different studied sediments. A significant correlation was shown between medaka embryo-larval assay by sediment contact and SOS chromotest responses and concentrations of most organic pollutants studied. No correlation was shown between pollutant levels and Microtox. According to the number of sediment samples detected as toxic, medaka embryo-larval assay by sediment contact was more sensitive than Microtox, which in turn was more sensitive than the SOS chromotest; and medaka embryo-larval assay by sediment contact allowed sediment toxicity assessment of moderately polluted sediments without pollutant extraction and using an ecologically realistic exposure scenario. Although medaka embryo-larval assay by sediment contact should be tested on a larger sample set, the results show that it is sensitive and convenient enough to monitor the toxicity of natural sediments. Environ Toxicol Chem 2016;35:2270-2280. © 2016 SETAC. © 2016 SETAC.

Fish short-term reproduction assay with atrazine and the Japanese medaka (Oryzias latipes).

Science.gov (United States)

Hosmer, Alan J; Schneider, Suzanne Z; Anderson, Julie C; Knopper, Loren D; Brain, Richard A

2017-09-01

Breeding groups of Japanese medaka (Oryzias latipes) were exposed to atrazine at measured concentrations of 0.6, 5.5, and 53 μg/L for 35 d. Evaluated endpoints included survival, fecundity, fertility, growth (weight and length), behavior, secondary sex characteristics (anal fin papillae), gonad histopathology, and hepatic vitellogenin. No statistically significant effects of atrazine exposure on survival and growth of medaka were noted during the test, and mean survival was ≥97.5% in all treatment groups on day 35. No significant effects of atrazine exposure on reproduction were observed. The number of mean cumulative eggs produced in the negative control and the 0.6, 5.5, and 53 μg/L treatment groups was 7158, 6691, 6883, and 6856, respectively. The mean number of eggs per female reproductive day was 40.9, 38.2, 40.2, and 39.2, respectively. There were also no dose-dependent effects on mean anal fin papillae counts among male fish or expression of vtg-II in males or females. In addition, atrazine exposure was not related to the developmental stage of test fish, with testes stages ranging from 2 to 3 in all groups and ovaries ranging from stage 2 to 2.5. Overall, exposure to atrazine up to 53 µg/L for 35 d did not result in significant, treatment-related effects on measured endpoints related to survival, growth, or reproduction in Japanese medaka. Environ Toxicol Chem 2017;36:2327-2334. © 2017 SETAC. © 2017 SETAC.

Ecotoxicity of halloysite nanotube-supported palladium nanoparticles in Raphanus sativus L.

Science.gov (United States)

Bellani, Lorenza; Giorgetti, Lucia; Riela, Serena; Lazzara, Giuseppe; Scialabba, Anna; Massaro, Marina

2016-10-01

Halloysite nanotubes (HNTs) are natural nanomaterials that are biocompatible and available in large amounts at low prices. They are emerging nanomaterials with appealing properties for applications like support for metal nanoparticles (NPs). The potential environmental impacts of NPs can be understood in terms of phytotoxicity. Current research has been focusing on HNT applications in cell or animal models, while their use in plants is limited so their ecotoxicological impact is poorly documented. To date there are no studies on the phytotoxic effects of functionalized halloysites (functionalized-HNTs). To develop a quantitative risk assessment model for predicting the potential impact of HNT-supported palladium nanoparticles (HNT-PdNPs) on plant life, an investigation was undertaken to explore their effects on seed germination, seedling development, and mitotic division in root tip cells of 2 lots of Raphanus sativus L. with different vigor. The results showed that exposure to 1500 mg/L of HNTs, functionalized-HNTs, and HNT-PdNPs had no significant influence on germination, seedling development, xylem differentiation, or mitotic index in both lots. Cytogenetic analyses revealed that treatments with functionalized-HNT significantly increased the number of aberrations in low-vigor seeds. These results suggest that low-vigor seeds represent a model for a stress test that would be useful to monitor the effects of NPs. Moreover the present study offers scientific evidence for the use of halloysite for environmental purposes, supporting the biological safety of HNT-PdNPs. Environ Toxicol Chem 2016;35:2503-2510. © 2016 SETAC. © 2016 SETAC.

Analyzing the capacity of the Daphnia magna and Pseudokirchneriella subcapitata bioavailability models to predict chronic zinc toxicity at high pH and low calcium concentrations and formulation of a generalized bioavailability model for D. magna.

Science.gov (United States)

Van Regenmortel, Tina; Berteloot, Olivier; Janssen, Colin R; De Schamphelaere, Karel A C

2017-10-01

Risk assessment in the European Union implements Zn bioavailability models to derive predicted-no-effect concentrations for Zn. These models are validated within certain boundaries (i.e., pH ≤ 8 and Ca concentrations ≥ 5mg/L), but a substantial fraction of the European surface waters falls outside these boundaries. Therefore, we evaluated whether the chronic Zn biotic ligand model (BLM) for Daphnia magna and the chronic bioavailability model for Pseudokirchneriella subcapitata could be extrapolated to pH > 8 and Ca concentrations model can accurately predict Zn toxicity for Ca concentrations down to 0.8 mg/L and pH values up to 8.5. Because the chronic Zn BLM for D. magna could not be extrapolated beyond its validity boundaries for pH, a generalized bioavailability model (gBAM) was developed. Of 4 gBAMs developed, we recommend the use of gBAM-D, which combines a log-linear relation between the 21-d median effective concentrations (expressed as free Zn 2+ ion activity) and pH, with more conventional BLM-type competition constants for Na, Ca, and Mg. This model is a first step in further improving the accuracy of chronic toxicity predictions of Zn as a function of water chemistry, which can decrease the uncertainty in implementing the bioavailability-based predicted-no-effect concentration in the risk assessment of high-pH and low-Ca concentration regions in Europe. Environ Toxicol Chem 2017;36:2781-2798. © 2017 SETAC. © 2017 SETAC.

Evaluation of an acute oral gavage method for assessment of pesticide toxicity in terrestrial amphibians.

Science.gov (United States)

Fort, Douglas J; Mathis, Michael B; Kee, Faith; Whatling, Paul; Clerkin, David; Staveley, Jane; Habig, Clifford

2018-02-01

Development of an acute oral toxicity test with a terrestrial-phase amphibian was considered necessary to remove the uncertainty within the field of agrochemical risk assessments. The bullfrog (Lithobates catesbeianus) was selected for use as it is a representative of the family Ranidae and historically this species has been used as an amphibian test model species. Prior to definitive study, oral gavage methods were developed with fenthion and tetraethyl pyrophosphate. Dimethoate and malathion were subsequently tested with both male and female juvenile bullfrogs in comprehensive acute oral median lethal dose (LD50) studies. Juvenile bullfrogs were administered a single dose of the test article via oral gavage of a single gelatin capsule of dimethoate technical (dimethoate) or neat liquid Fyfanon ® Technical (synonym malathion), returned to their respective aquaria, and monitored for survival for 14 d. The primary endpoint was mortality, whereas behavioral responses, food consumption, body weight, and snout-vent length (SVL) were used to evaluate indications of sublethal toxicity (secondary endpoints). Acute oral LD50 values (95% fiducial interval) for dimethoate were 1459 (1176-1810, males) and 1528 (1275-1831, females), and for malathion they were 1829 (1480-2259, males) and 1672 (1280-2183, females) mg active substance/kg body weight, respectively. Based on the results of these studies, the methodology for the acute oral gavage administration of test items to terrestrial-phase amphibians was demonstrated as being a practical method of providing data for risk assessments. Environ Toxicol Chem 2018;37:436-450. © 2017 SETAC. © 2017 SETAC.

Miniature circulatory systems: A new exposure system for ecotoxicological effect assessments in riverine organisms.

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Feiner, Mona; Beggel, Sebastian; Geist, Juergen

2016-11-01

Long-term effect assessments in ecotoxicological investigations are important, yet there is a lack of suitable exposure systems for these experiments that can be used for riverine species. A cost-efficient miniature circulatory system was developed that was evaluated for its applicability in long-term exposures in 2 stream-dwelling species: brown trout (Salmo trutta) and an amphipod (Gammarus roeseli). In an egg-to-fry exposure of S. trutta, the toxicity of 2 reverse osmosis concentrates was investigated as examples. Control hatching rate of yolk sac fry was 75 ± 7% and thus complies with the Organisation for Economic Co-operation and Development validity criterion (≥66%). The reverse osmosis concentrates did not impair the hatching rate in any tested concentration. In G. roeseli, mortality rates remained below 20% during a 21-d cultivation, fulfilling the common validity criterion in ecotoxicological testing. Mortality was significantly lower when the species was fed with conditioned alder leaves instead of an artificial shrimp food. Finally, a toxicity test on G. roeseli using copper as the test substance revealed median lethal concentration (LC50) values of 156 μg/L after 96 h and 99 μg/L after 264 h, which is in line with literature findings using other accepted exposure units. In conclusion, the miniature circulatory system provides a novel and cost-efficient exposure system for long-term investigations on riverine species that may also be applicable for other species of fishes and macroinvertebrates. Environ Toxicol Chem 2016;35:2827-2833. © 2016 SETAC. © 2016 SETAC.

Phototoxic potential of undispersed and dispersed fresh and weathered Macondo crude oils to Gulf of Mexico Marine Organisms.

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Finch, Bryson E; Marzooghi, Solmaz; Di Toro, Dominic M; Stubblefield, William A

2017-10-01

Crude oils contain a mixture of hydrocarbons, including phototoxic polycyclic aromatic hydrocarbons (PAHs) that have the ability to absorb ultraviolet (UV) light. Absorption of UV light by PAHs can substantially increase their toxicity to marine organisms. The objective of the present study was to examine the potential for phototoxicity of fresh and naturally weathered Macondo crude oils alone and in combination with the dispersant Corexit 9500 to mysid shrimp (Americamysis bahia), inland silverside (Menidia beryllina), sheepshead minnow (Cyprinodon variegatus), and Gulf killifish (Fundulus grandis). Acute toxicity tests were conducted using combinations of natural or artificial sunlight and low-energy water-accommodated fractions (WAFs) of fresh and weathered Macondo crude oils collected from the Gulf of Mexico. Studies were also conducted to compare the phototoxicity resulting from natural and artificial sunlight. Fresh Macondo crude oil was more phototoxic than weathered crude oils, both in the presence and in the absence of UV light. Differences in toxicity between fresh and weathered crude oils were likely attributed to lighter-ringed PAHs in fresh crude oils. Phototoxic PAHs were relatively resistant to weathering compared with lighter-ringed PAHs. The addition of Corexit 9500 to crude oil increased toxicity compared with tests with crude oil alone, by increasing phototoxic PAH concentrations in WAFs. Macondo crude oils had the potential to be phototoxic to Gulf of Mexico marine organisms if specific light conditions and PAH concentrations were present during the Deepwater Horizon oil spill. Environ Toxicol Chem 2017;36:2640-2650. © 2017 SETAC. © 2017 SETAC.

Effects of ivermectin application on the diversity and function of dung and soil fauna: Regulatory and scientific background information.

Science.gov (United States)

Adler, Nicole; Bachmann, Jean; Blanckenhorn, Wolf U; Floate, Kevin D; Jensen, John; Römbke, Jörg

2016-08-01

The application of veterinary medical products to livestock can impact soil organisms in manure-amended fields or adversely affect organisms that colonize dung pats of treated animals and potentially retard the degradation of dung on pastures. For this reason, the authorization process for veterinary medicinal products in the European Union includes a requirement for higher-tier tests when adverse effects on dung organisms are observed in single-species toxicity tests. However, no guidance documents for the performance of higher-tier tests are available. Hence, an international research project was undertaken to develop and validate a proposed test method under varying field conditions of climate, soil, and endemic coprophilous fauna at Lethbridge (Canada), Montpellier (France), Zurich (Switzerland), and Wageningen (The Netherlands). The specific objectives were to determine if fecal residues of an anthelmintic with known insecticidal activity (ivermectin) showed similar effects across sites on 1) insects breeding in dung of treated animals, 2) coprophilous organisms in the soil beneath the dung, and 3) rates of dung degradation. By evaluating the effects of parasiticides on communities of dung-breeding insects and soil fauna under field conditions, the test method meets the requirements of a higher-tier test as mandated by the European Union. The present study provides contextual information on authorization requirements for veterinary medicinal products and on the structure and function of dung and soil organism communities. It also provides a summary of the main findings. Subsequent studies on this issue provide detailed information on different aspects of this overall project. Environ Toxicol Chem 2016;35:1914-1923. © 2015 SETAC. © 2015 SETAC.

Effects of spray drift of glyphosate on nontarget terrestrial plants-A critical review.

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Cederlund, Harald

2017-11-01

Glyphosate is a widely used broad-spectrum postemergent herbicide used for weed control in both agricultural and nonagricultural settings. Spray drift of glyphosate can pose a risk to nontarget terrestrial plants and plant communities outside the intended area of application, but the lack of a well-established predicted-no-effect drift rate makes properly assessing such risk difficult. For this reason, a literature review and meta-analysis was carried out with the aim to determine the level of drift that is likely to cause harm to plants and to explore what spray-reducing targets would be sufficiently protective. No-observed-adverse effect rates, lowest-observed-adverse effect rates, and effect rates giving 10, 25, and 50% effects were extracted from a total of 39 different publications. The data were combined per species, and species sensitivity distributions were constructed and fitted with a log-logistic model to assess protectiveness. No systematic differences were detected between the responses of monocotyledons or dicotyledons, but wild plants were found to be generally less sensitive to glyphosate drift than domesticated plants. The results indicate that restricting spray drift to a level below 5 g a.e./ha would protect approximately 95% of all higher plant species against minor adverse effects of glyphosate drift and that rates below 1 to 2 g a.e./ha would be almost completely protective. No studies were encountered that evaluated effects of spray drift against nonvascular plants, and therefore, the conclusions are only valid for vascular plants. Environ Toxicol Chem 2017;36:2879-2886. © 2017 SETAC. © 2017 SETAC.

The toxicity of different lead salts to Enchytraeus crypticus in relation to bioavailability in soil.

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Zhang, Lulu; Van Gestel, Cornelis A M

2017-08-01

The present study aimed to assess the bioavailability and toxicity of lead nitrate and lead chloride to Enchytraeus crypticus in a natural standard soil. Worms were exposed to Pb-spiked soil for 21 d, and survival and reproduction were related to total, 0.01 M CaCl 2 -extractable, and porewater Pb concentrations in the soil and internal concentrations in the surviving animals. The Pb availability for Pb(NO 3 ) 2 and PbCl 2 was similar, as confirmed by Langmuir and Freundlich isotherms. The Pb concentrations in surviving worms increased with increasing Pb concentrations in the soil and did not differ for the 2 Pb salts. Lead was toxic to E. crypticus at median lethal concentrations (LC50s) of 543 and 779 mg Pb/kg dry soil and median effect concentrations (EC50s) of 189 and 134 mg Pb/kg dry soil, for Pb(NO 3 ) 2 and PbCl 2 , respectively. Mortality of E. crypticus was related to internal Pb concentrations in the worms rather than to total or available Pb concentrations in the soil, whereas reproduction toxicity was better explained from Pb concentrations in 0.01 M CaCl 2 extracts or porewater of the test soil than from total Pb concentrations in the soil or Pb concentrations in the worms. Overall, the bioavailability and toxicity of Pb(NO 3 ) 2 and PbCl 2 to E. crypticus in LUFA 2.2 soil did not differ. Environ Toxicol Chem 2017;36:2083-2091. © 2017 SETAC. © 2017 SETAC.

Thiol oxidation of hemolymph proteins in oysters Crassostrea brasiliana as markers of oxidative damage induced by urban sewage exposure.

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Trevisan, Rafael; Flores-Nunes, Fabrício; Dolores, Euler S; Mattos, Jacó J; Piazza, Clei E; Sasaki, Sílvio T; Taniguchi, Satie; Montone, Rosalinda C; Bícego, Márcia C; Dos Reis, Isis M M; Zacchi, Flávia L; Othero, Bárbara N M; Bastolla, Camila L V; Mello, Danielle F; Fraga, Ana Paula M; Wendt, Nestor; Toledo-Silva, Guilherme; Razzera, Guilherme; Dafre, Alcir L; de Melo, Cláudio M R; Bianchini, Adalto; Marques, Maria R F; Bainy, Afonso C D

2017-07-01

Urban sewage is a concerning issue worldwide, threatening both wildlife and human health. The present study investigated protein oxidation in mangrove oysters (Crassostrea brasiliana) exposed to seawater from Balneário Camboriú, an important tourist destination in Brazil that is affected by urban sewage. Oysters were exposed for 24 h to seawater collected close to the Camboriú River (CAM1) or 1 km away (CAM2). Seawater from an aquaculture laboratory was used as a reference. Local sewage input was marked by higher levels of coliforms, nitrogen, and phosphorus in seawater, as well as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), linear alkylbenzenes (LABs), and fecal steroid in sediments at CAM1. Exposure of oysters to CAM1 caused marked bioaccumulation of LABs and decreased PAH and PCB concentrations after exposure to both CAM1 and CAM2. Protein thiol oxidation in gills, digestive gland, and hemolymph was evaluated. Lower levels of reduced protein thiols were detected in hemolymph from CAM1, and actin, segon, and dominin were identified as targets of protein thiol oxidation. Dominin susceptibility to oxidation was confirmed in vitro by exposure to peroxides and hypochlorous acid, and 2 cysteine residues were identified as potential sites of oxidation. Overall, these data indicate that urban sewage contamination in local waters has a toxic potential and that protein thiol oxidation in hemolymph could be a useful biomarker of oxidative stress in bivalves exposed to contaminants. Environ Toxicol Chem 2017;36:1833-1845. © 2016 SETAC. © 2016 SETAC.

Calibration of silicone rubber rods as passive samplers for pesticides at two different flow velocities: Modeling of sampling rates under water boundary layer and polymer control.

Science.gov (United States)

Martin, Alexis; Margoum, Christelle; Jolivet, Antoine; Assoumani, Azziz; El Moujahid, Bachir; Randon, Jérôme; Coquery, Marina

2018-04-01

There is a need to determine time-weighted average concentrations of polar contaminants such as pesticides by passive sampling in environmental waters. Calibration data for silicone rubber-based passive samplers are lacking for this class of compounds. The calibration data, sampling rate (R s ), and partition coefficient between silicone rubber and water (K sw ) were precisely determined for 23 pesticides and 13 candidate performance reference compounds (PRCs) in a laboratory calibration system over 14 d for 2 water flow velocities, 5 and 20 cm s -1 . The results showed that an in situ exposure duration of 7 d left a silicone rubber rod passive sampler configuration in the linear or curvilinear uptake period for 19 of the pesticides studied. A change in the transport mechanism from polymer control to water boundary layer control was observed for pesticides with a log K sw of approximately 3.3. The PRC candidates were not fully relevant to correct the impact of water flow velocity on R s . We therefore propose an alternative method based on an overall resistance to mass transfer model to adjust R s from laboratory experiments to in situ hydrodynamic conditions. We estimated diffusion coefficients (D s ) and thickness of water boundary layer (δ w ) as adjustable model parameters. Log D s values ranged from -12.13 to -10.07 m 2  s -1 . The estimated δ w value showed a power function correlation with water flow velocity. Environ Toxicol Chem 2018;37:1208-1218. © 2017 SETAC. © 2017 SETAC.

Toxicity of three strobilurins (kresoxim-methyl, pyraclostrobin, and trifloxystrobin) on Daphnia magna.

Science.gov (United States)

Cui, Feng; Chai, Tingting; Liu, Xiaoxu; Wang, Chengju

2017-01-01

Strobilurins constitute a new class of fungicides that is the most widely used in the world. The present study was conducted to investigate the aquatic toxicity of 3 common strobilurin fungicides (kresoxim-methyl, pyraclostrobin, and trifloxystrobin) to Daphnia magna. The neonate acute immobilization test showed that the 48-h 50% effective concentration (EC50) values of kresoxim-methyl, pyraclostrobin, and trifloxystrobin were 443.3 µg/L, 20.9 µg/L, and 23.0 µg/L, respectively. In addition, the 3 strobilurins significantly induced activity of the important detoxification enzyme glutathione S-transferase (GST) in D. magna, and there was a significant positive relationship between GST activity and immobility of D. magna after acute exposure. The 3 strobilurins showed higher toxicity to D. magna embryos, and the 48-h EC50 were 157.3 µg/L, 3.9 µg/L, and 1.7 µg/L for kresoxim-methyl, pyraclostrobin, and trifloxystrobin, respectively. The 21-d chronic test revealed that the strobilurins could also significantly affect the reproduction, development, and growth of D. magna at sublethal concentrations. The lowest-observed-effect concentrations of kresoxim-methyl, pyraclostrobin, and trifloxystrobin for reproduction were 20 µg/L, 0.15 µg/L, and 0.2 µg/L, respectively, which were close to environmental concentrations. The findings indicate that strobilurin fungicides are very toxic to D. magna and they are sufficient to cause harm to D. magna at environmentally relevant concentrations. Environ Toxicol Chem 2017;36:182-189. © 2016 SETAC. © 2016 SETAC.

Development of Helisoma trivolvis pond snails as biological samplers for biomonitoring of current-use pesticides.

Science.gov (United States)

Morrison, Shane A; Belden, Jason B

2016-09-01

Nontarget aquatic organisms residing in wetlands are commonly exposed to current-use pesticides through spray drift and runoff. However, it is frequently challenging to measure exposure because of rapid dissipation of pesticides from water and reduced bioavailability. The authors' hypothesis is that freshwater snails can serve as bioindicators of pesticide exposure based on their capacity to passively accumulate tissue residues. Helisoma trivolvis snails were evaluated as biomonitors of pesticide exposure using a fungicide formulation that contains pyraclostrobin and metconazole and is frequently applied to crops surrounding depressional wetlands. Exposure-response studies indicate that H. trivolvis are tolerant of pyraclostrobin and metconazole at concentrations >10 times those lethal to many aquatic species, with a median lethal concentration based on pyraclostrobin of 441 μg/L (95% confidence interval of 359-555 μg/L). Bioconcentration factors ranged from 137 mL/g to 211 mL/g and from 39 mL/g to 59 mL/g for pyraclostrobin and metconazole, respectively. Elimination studies suggested one-compartmental elimination and snail tissue half-lives (t50 ) of approximately 15 h and 5 h for pyraclostrobin and metconazole, respectively. Modeling derived toxicokinetic parameters in the context of an environmentally relevant pulsed exposure suggests that residues can be measured in snails long after water concentrations fall below detection limits. With high fungicide tolerance, rapid accumulation, and slow elimination, H. trivolvis may be viable for biomonitoring of pyraclostrobin and should be investigated for other pesticides. Environ Toxicol Chem 2016;35:2320-2329. © 2016 SETAC. © 2016 SETAC.

Isotopic exchange on solid-phase micro extraction fiber in sediment under stagnant conditions: Implications for field application of performance reference compound calibration.

Science.gov (United States)

Bao, Lian-Jun; Wu, Xiaoqin; Jia, Fang; Zeng, Eddy Y; Gan, Jay

2016-08-01

An overlooked issue for field application of in situ performance reference compound (PRC) calibration methods is the validity of the assumption that both the sorption of a target compound and desorption of its corresponding PRC follow the first-order kinetics with the same rate constants under stagnant conditions. In the present study, disposable polydimethylsiloxane fibers of 2 sizes (7 and 35 µm) impregnated with 8 (13) C-labeled or deuterated PRCs were statically deployed into different marine sediments, from which the kinetics for sorption of the target compounds and desorption of the PRCs were characterized. Nonsymmetrical profiles were observed for exchange of the target analytes and their corresponding PRCs in sediment under stagnant conditions. The hysteretic desorption of PRCs in the kinetic regime may be ascribed to the low chemical potential between the fiber and sediment porewater, which reflects the inability of water molecules to rapidly diffuse through sediment to solvate the PRCs in the aqueous layer around the fiber surface. A moderate correlation (r = 0.77 and r = 0.57, p < 0.05 for both regressions) between the PRC-calibrated equilibrium concentrations of 1,1-dichloro-2,2-bis-(chlorophenyl) ethylene (p,p'-DDE) and polychlorinated biphenyl (PCB)-153 and the lipid normalized levels in worms (Neanthes arenaceodentata) was obtained in co-exposure tests under simulating field conditions, probably resulting from slightly overestimated bioavailability because of the hysteretic desorption of PRCs and toxic effects. Environ Toxicol Chem 2016;35:1978-1985. © 2015 SETAC. © 2015 SETAC.

New clinical and toxicological scenario of gammaglutamyltranspeptidase Nueva singladura clínica y toxicológica de la gammaglutamiltranspeptidasa

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Ramón Bataller-Sifre

2011-11-01

desarrollo de diabetes. Por otro lado numerosos fármacos inducen la enzima tisular (microsomas pudiendo dar elevaciones séricas que no suponen daño estructural a nivel hepático. Su ubicuidad anátomo-citológica hace que pueda aumentar en suero en numerosos procesos, siendo por ello en ocasiones dificultoso patentizar su origen. Finalmente, desde un ángulo epidemiológico y toxicológico, siendo que el glutatión es necesario para conjugar diversas sustancias químicas, la enzima resultaría un biomarcador, entre otros, de numerosas sustancias nocivas medioambientales. Se incide en conjunto en este ensanchamiento del significado clínico y diagnóstico de una enzima que se creía suficientemente conocida desde hace medio siglo en que se descubrió.

Estudo fitoquímico e bioensaio toxicológico frente a larvas de Artemia salina Leach. de três espécies medicinais do gênero Phyllanthus (Phyllanthaceae

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J. E. Nascimento

2009-02-01

Full Text Available

Avaliou-se o perfil fitoquímico e a toxicidade de três espécies do gênero Phyllanthus (P. niruri, P. amarus e P. tenellus, coletadas em diferentes localidades do estado de Pernambuco, nordeste do Brasil. Os extratos brutos das três espécies foram submetidos a testes convencionais por cromatografia em camada delgada analítica para verificação das classes de metabólitos presentes, e testados frente a larvas de Artemia salina para obtenção das concentrações letais médias (CL50. Os testes fitoquímicos demonstraram a presença de flavonóides, saponinas, terpenos, naftoquinonas, alcalóides, antraquinonas, lignanas e taninos. As três espécies de Phyllanthus apresentaram variações na composição fitoquímica e na toxicidade frente a A. salina. Dependendo do local de coleta, os valores de CL50 variaram de 404,43 ± 49,64 µg/mL a 770,84 ± 51,78 µg/mL para P. niruri, 837,65 ± 61,45 µg/mL a 1075,89 ± 70,72 µg/mL para P. amarus e 534,60 ± 46,83 µg/mL a 1003,62 ± 65,15 µg/mL para P. tenellus. Palavras-chave: Phyllanthus niruri; Phyllanthus amarus,/i>; Phyllanthus tenellus; análise fitoquímica preliminar; bioensaio toxicológico; CL50

Effects of two commonly used fungicides on the amphipod Austrochiltonia subtenuis.

Science.gov (United States)

Vu, Hung T; Keough, Michael J; Long, Sara M; Pettigrove, Vincent J

2017-03-01

Fungicides are used widely in agriculture and have been detected in adjacent rivers and wetlands. However, relatively little is known about the potential effects of fungicides on aquatic organisms. The present study investigated the effects of 2 commonly used fungicides, the boscalid fungicide Filan ® and the myclobutanil fungicide Systhane ™ 400 WP, on life history traits (survival, growth, and reproduction) and energy reserves (lipid, protein, and glycogen content) of the amphipod Austrochiltonia subtenuis under laboratory conditions, at concentrations detected in aquatic environments. Amphipods were exposed to 3 concentrations of Filan (1 μg active ingredient [a.i.]/L, 10 μg a.i./L, and 40 μg a.i./L) and Systhane (0.3 μg a.i./L, 3 μg a.i./L, and 30 μg a.i./L) over 56 d. Both fungicides had similar effects on the amphipod at the organism level. Reproduction was the most sensitive endpoint, with offspring produced in controls but none produced in any of the fungicide treatments, and total numbers of gravid females in all fungicide treatments were reduced by up to 95%. Female amphipods were more sensitive than males in terms of growth. Systhane had significant effects on survival at all concentrations, whereas significant effects of Filan on survival were observed only at 10 μg a.i./L and 40 μg a.i./L. The effects of fungicides on energy reserves of the female amphipod were different. Filan significantly reduced amphipod protein content, whereas Systhane significantly reduced the lipid content. The present study demonstrates wide-ranging effects of 2 common fungicides on an ecologically important species that has a key role in trophic transfer and nutrient recycling in aquatic environments. These results emphasize the importance of considering the long-term effects of fungicides in the risk assessment of aquatic ecosystems. Environ Toxicol Chem 2017;36:720-726. © 2016 SETAC. © 2016 SETAC.

Modelling of Impulsional pH Variations Using ChemFET-Based Microdevices: Application to Hydrogen Peroxide Detection

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Abdou Karim Diallo

2014-02-01

Full Text Available This work presents the modelling of impulsional pH variations in microvolume related to water-based electrolysis and hydrogen peroxide electrochemical oxidation using an Electrochemical Field Effect Transistor (ElecFET microdevice. This ElecFET device consists of a pH-Chemical FET (pH-ChemFET with an integrated microelectrode around the dielectric gate area in order to trigger electrochemical reactions. Combining oxidation/reduction reactions on the microelectrode, water self-ionization and diffusion properties of associated chemical species, the model shows that the sensor response depends on the main influential parameters such as: (i polarization parameters on the microelectrode, i.e., voltage (Vp and time (tp; (ii distance between the gate sensitive area and the microelectrode (d; and (iii hydrogen peroxide concentration ([H2O2]. The model developed can predict the ElecFET response behaviour and creates new opportunities for H2O2-based enzymatic detection of biomolecules.

Calidad fisicoquímica, microbiológica y toxicológica de leche cruda en las cuencas ganaderas de la región Puno –Perú

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Magaly Brousett-Minaya

2015-01-01

Full Text Available El objetivo del presente trabajo fue evaluar la calidad de la leche cruda en cuanto a sus propiedades fisicoquímicas, microbiológicas y toxicológicas en siete cuencas representativas de la región Puno. Los resultados fueron comparados con los estándares establecidos en la Norma Técnica Peruana para leche y productos lácteos NTP 200.001-2003 y con la Norma oficial mexicana NOM-155-SCFI-2012 para los parámetros de proteína y lactosa en ausencia de parámetros peruanos. Para la caracterización fisicoquímica se determinó pH, acidez, densidad, contenido de grasa, proteína, lactosa, sólidos totales y sólidos no grasos; también se realizaron análisis microbiológicos de E. Coli y mesófilos. Del mismo modo el estudio abarcó el análisis de residuos de pesticidas como son organoclorados, organofosforados, carbamatos y piretroides en concentración de 1,0 ug/g de muestra los cuales dieron resultados negativos para los cuatro grupos de pesticidas, las determinaciones fisicoquímicas en más del 50% de las cuencas (a excepción de acidez y pH se encontraron dentro de los estándares de la NTP y la NOM. La presencia de mesófilos en su mayoría fueron encontrados dentro de los parámetros establecidos a excepción de dos cuencas lecheras y en cuanto a E. Coli ninguna cuenca cumplió con las normas establecidas encontrándose una leche de baja calidad higiénica.

Iodine's impact on tropospheric oxidants: a global model study in GEOS-Chem

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T. Sherwen

2016-02-01

Full Text Available We present a global simulation of tropospheric iodine chemistry within the GEOS-Chem chemical transport model. This includes organic and inorganic iodine sources, standard gas-phase iodine chemistry, and simplified higher iodine oxide (I2OX, X = 2, 3, 4 chemistry, photolysis, deposition, and parametrized heterogeneous reactions. In comparisons with recent iodine oxide (IO observations, the simulation shows an average bias of  ∼ +90 % with available surface observations in the marine boundary layer (outside of polar regions, and of  ∼ +73 % within the free troposphere (350 hPa  <  p  <  900 hPa over the eastern Pacific. Iodine emissions (3.8 Tg yr−1 are overwhelmingly dominated by the inorganic ocean source, with 76 % of this emission from hypoiodous acid (HOI. HOI is also found to be the dominant iodine species in terms of global tropospheric IY burden (contributing up to 70 %. The iodine chemistry leads to a significant global tropospheric O3 burden decrease (9.0 % compared to standard GEOS-Chem (v9-2. The iodine-driven OX loss rate1 (748 Tg OX yr−1 is due to photolysis of HOI (78 %, photolysis of OIO (21 %, and reaction between IO and BrO (1 %. Increases in global mean OH concentrations (1.8 % by increased conversion of hydroperoxy radicals exceeds the decrease in OH primary production from the reduced O3 concentration. We perform sensitivity studies on a range of parameters and conclude that the simulation is sensitive to choices in parametrization of heterogeneous uptake, ocean surface iodide, and I2OX (X = 2, 3, 4 photolysis. The new iodine chemistry combines with previously implemented bromine chemistry to yield a total bromine- and iodine-driven tropospheric O3 burden decrease of 14.4 % compared to a simulation without iodine and bromine chemistry in the model, and a small increase in OH (1.8 %. This is a significant impact and so halogen chemistry needs to be

Phosphine Toxicity: A Story of Disrupted Mitochondrial Metabolism

Science.gov (United States)

2016-05-24

Phosphine and selected metal phosphides. Environ. Health Criteria 73. 5. Reeve, I. 2014. Estimation of exposure to persons in Califor- nia ...Gill. 2011. Aluminum phosphide poisoning: an unsolved riddle. J. Appl. Toxicol. 31: 499– 505 . 9. Lam, W.W., R.F. Toia & J. Casida. 1991. Oxidatively...Trends Biochem. Sci. 35: 505 –513. 43. Turrens, J.F. 2003. Mitochondrial formation of reactive oxy- gen species. J. Physiol. 552: 335–344. 44. Fridovich

Chemical effects in 11-year solar cycle simulations with the Freie Universität Berlin Climate Middle Atmosphere Model with online chemistry (FUB-CMAM-CHEM)

OpenAIRE

U. Langematz; J. Grenfell; K. Matthes; P. Mieth; M. Kunze; B. Steil; C. Brühl;  

2005-01-01

The impact of 11-year solar cycle variations on stratospheric ozone (O3) is studied with the Freie Universität Berlin Climate Middle Atmosphere Model with interactive chemistry (FUB-CMAM-CHEM). To consider the effect of variations in charged particle precipitation we included an idealized NO x source in the upper mesosphere representing relativistic electron precipitation (REP). Our results suggest that the NO x source by particles and its transport from the mesosphere to the stratosphe...

Estudos pré-clínicos e clínicos de espécies vegetais selecionadas de países pertencentes ao Mercosul e aspectos toxicológicos

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Camile Cecconi CECHINEL-ZANCHETT

2017-12-01

Full Text Available As plantas medicinais são utilizadas para a prevenção e tratamento de doenças, sendo usada por cerca de 80% da população para o cuidado primário à saúde. A rica biodiversidade do Brasil e países vizinhos oferece um potencial único e incomparável para a descoberta e desenvolvimento de agentes bioativos. O objetivo desse trabalho foi fazer uma revisão sobre estudos pré-clínicos e clínicos de espécies vegetais selecionadas dos países do Mercosul e aspectos toxicológicos. Com base em trabalho publicado anteriormente pelo autor, foram selecionadas as espécies com maior número de registro na Anvisa no Brasil (Aesculus hippocastanum - Castanha da Índia e Mikania glomerata- Guaco; as mais utilizadas como medicamentos fitoterápicos simples na Argentina (Cynara scolymus L. - Alcachofra e Solanum dulcamara - Dulcamara; as plantas medicinais mais vendidas no Paraguai (Peumus boldus Mol. - Boldo e Borago officinalis - Borragem; as mais consumidas no norte do Uruguai (Aloe vera – Aloe e Passiflora edulis - Maracujá e da Venezuela a Hedera helix (Hera por ser muito popular no país seu consumo. Foram realizadas pesquisas nas bases de dados Google Acadêmico, PubMed e Science Direct no mês de abril de 2016, sobre ensaios pré-clínicos e clínicos dessas espécies vegetais, em português e inglês, sendo selecionados os artigos mais relevantes, com uso de animais (ratos, coelhos ou camundongos, linhagens celulares ou bacterianas, ou estudos clínicos. Em relação aos estudos pré-clínicos e clínicos, Aloe e Alcachofra, foram as que apresentaram maior número de publicações.

Kanishka Biswas

Indian Academy of Sciences (India)

Kanishka Biswas

(Solid state inorganic chemistry). (Metal chalcogenide chemistry). Manoj K. Jana. Satya N. Guin. Ananya Banik. Subhajit. Roychowdhury. Manisha Samanta Ekashmi. Rathore. Sujoy Saha. Thermoelectrics. Guin et al. Energy Environ. Sci., 2013, 6, 2603. Guin et al. J. Mater. Chem. A 2014, 2, 4324. Guin, et al. J. Am. Chem.

QSAR screening of 70,983 REACH substances for genotoxic carcinogenicity, mutagenicity and developmental toxicity in the ChemScreen project

DEFF Research Database (Denmark)

Wedebye, Eva Bay; Dybdahl, Marianne; Nikolov, Nikolai Georgiev

2015-01-01

The ChemScreen project aimed to develop a screening system for reproductive toxicity based on alternative methods. QSARs can, if adequate, contribute to the evaluation of chemical substances under REACH and may in some cases be applied instead of experimental testing to fill data gaps...... for information requirements. As no testing for reproductive effects should be performed in REACH on known genotoxic carcinogens or germ cell mutagens with appropriate risk management measures implemented, a QSAR pre-screen for 70,983 REACH substances was performed. Sixteen models and three decision algorithms...... were used to reach overall predictions of substances with potential effects with the following result: 6.5% genotoxic carcinogens, 16.3% mutagens, 11.5% developmental toxicants. These results are similar to findings in earlier QSAR and experimental studies of chemical inventories, and illustrate how...

Handheld highly selective plasmonic chem/biosensor using engineered binding proteins for extreme conformational changes

Science.gov (United States)

Kosciolek, Derek J.; Sonar, Ajay; Lepak, Lori A.; Schnatz, Peter; Bendoym, Igor; Brown, Mia C.; Koder, Ronald L.; Crouse, David T.

2017-08-01

In this project we develop a handheld, portable, highly selective and sensitive chem/biosensor that has potential applications in both airborne and water-based environmental sensing. The device relies on a plasmonic chip of subwavelength-scale periodic gold rods engineered to resonate in the near infrared. The chip is functionalized with a novel class of proteins that exhibit large conformational changes upon binding to a specific target analyte. The subsequent change in local refractive index near the surface of the gold is one to two orders of magnitude greater than current conventional methods, which produces a readily measurable 5 to 10 percent difference in light transmission. This allows us to forgo traditional, bulky tabletop setups in favor of a compact form factor. Using commercially available optics to construct a transmission-based optical train, measured changes in bulk refractive index are presented here. While synthesis of binding protein efforts are focused on heme as analyte for proof of concept validation, the functionalized protein can be engineered to pair with a wide variety of analytes with minimal alterations to the plasmonic chip or device design. Such flexibility allows for this device to potentially meet the needs of first responders and health care professionals in a multitude of scenarios.

Avaliação toxicológica e reprodutiva de camundongos machos adultos tratados com femproporex = Fenproporex treatment in male mice: behavior and toxicology reproductive analysis

Directory of Open Access Journals (Sweden)

José Eduardo Baroneza

2007-07-01

Full Text Available O femproporex é utilizado no mundo todo como potente anorexígeno. Esteestudo visa esclarecer se o uso diário de femproporex provoca toxicidade comportamental e/ou reprodutiva em camundongos machos adultos. Para tanto, foram utilizados 40 camundongos, divididos em quatro grupos experimentais, cada um contendo dez animais. Um dos grupos recebeu, via gavage, apenas água, e os outros foram tratados diariamente com femproporex, nas doses de 7,5, 15 e 30 mg kg-1, por um período de 40 dias. Como resultados, verificou-se que o femproporex não alterou a evolução normal da massa dos animais analisados, e concluiu-se que a utilização da droga não promoveu toxicidade comportamental, verificada nos testes de natação forçada e de campo aberto; e reprodutiva, quando verificados genotoxicidade, síntese de testosterona, morfologia de espermatozóides e histologia testicular. Assim sendo, concluiu-se que o femproporex, na concentração e delineamentos experimentais propostos por este trabalho, não apresentou potencial toxicológico.Fenproporex is used worldwide as a powerful anorectic drug.This study was designed to evaluate whether daily intake of fenproporex would lead to behavioral and/or reproductive toxicity in adult male mice. Fourty male mice were used, divided into 4 groups of 10 animals each. The control group received only water by gavage, whereas the experimental groups were treated daily with fenproporex in the doses of 7.5, 15 and 30 mg kg-1, for a period of 40 days. The results demonstrated that fenproporex did not alter the normal evolution of the animals’ body mass; it also showed that the use of the drug did not promote behavioral toxicity (open-field and forcedswimming tests or reproductive toxicity (genotoxicity, changes in the morphology of spermatozoa and testicular histology. Thus, the present results indicate that fenproporex, in the evaluated dose and experimental conditions, does not present behavioral and reproductive

Assessing the Impact of Oil and Natural Gas Activities on Regional Air Quality in the Colorado Northern Front Range using WRF-Chem

Science.gov (United States)

Abdioskouei, M.; Carmichael, G. R.

2017-12-01

Recent increases in the Natural Gas (NG) production through hydraulic fracturing have questioned the climate benefit of switching from coal-fired to natural gas-fired power plants. Higher than expected levels of methane, VOCs, and NOx have been observed in areas close to oil and NG (OnG) operation facilities. High uncertainty in the OnG emission inventories and methane budget challenge the assessment of OnG impact on air quality and climate and consequently development of effective mitigation policies and control regulations. In this work, we focus on reducing the uncertainties around the OnG emissions by using high resolution (4x4 km2) WRF-Chem simulations coupled with detailed observation from the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ 2014) field campaign. First, we identified the optimal WRF-Chem configurations in the NFR area. We compared the performance of local and non-local Planetary Boundary Layer (PBL) schemes in predicting the PBL height and vertical mixing in the domain. We evaluated the impact of different meteorological and chemical initial and boundary conditions on the model performance. Next, simulations based on optimal configurations were used to assess the performance of the emission inventory (NEI-2011v2). To evaluate the impact of OnG emission on regional air quality and performance of NEI-2011 we tested the sensitivity of the model to the OnG emission. Comparison between simulated values and ground-based and airborne measurements shows a low bias of OnG emission in NEI-2011. Finally, inverse modeling techniques based on emission sensitivity simulations are being used to optimal scaling the OnG emission from the NEI-2011.

Retraction notice to: Environmental cadmium and zinc concentrations in liver and kidney of European hare from different Serbian regions, Zoran I. Petrović, Vlado B. Teodorović, Mirjana R. Dimitrijević, Sunčica Z. Borozan, Miloš T. Beuković, Dragica M. Nikolić, Aurelija T. Spirić , [Hem. Ind. 67 (4) 593-599 (2013) DOI: 10.2298/HEMIND120815100P

OpenAIRE

Editorial

2015-01-01

This article has been retracted at the request of authors. The retraction has been made because the authors admitted that they have done dual submission of the text and drawings from article named "Environmental Cd and Zn Concentrations in Liver and Kidney of European Hare from Different Serbian Regions: Age and Tissue Differences" published in Bull Environ Contam Toxicol (2013) 90:203-207 DOI 10.1007/s00128-012-0901-7. One of the conditions of submission...

Ex-ORISKANY Artificial Reef Project: Ecological Risk Assessment

Science.gov (United States)

2006-01-25

Assuming that light will penetrate to the depths of the reef, species of encrusting algae and other macrophytes will colonize on the surface of the...Environ. Contam. Toxicol. 16:283-290. Kraak, M.H.S., M. Toussaint, E.A.J. Bleeker and D. Lavy, 1993. p. 175 - 186 in Dallinger, R. et.al. Ecotoxicology ...Sensitivity Distributions in Ecotoxicology , Lewis, Boca Raton, FL, USA. http://www.environetbase.com/ejournals/books/book_summary/toc.asp?id=707 Poulton

Influence of non ionizing radiation of base stations on the activity of redox proteins in bovines

OpenAIRE

Hässig, Michael; Wullschleger, Marietta; Naegeli, Hanspeter; Kupper, Jaqueline; Spiess, Bernhard; Kuster, Niels; Capstick, Myles; Murbach, Manuel

2014-01-01

Background: The influence of electromagnetic fields on the health of humans and animals is still an intensively discussed and scientifically investigated issue (Prakt Tierarzt 11:15-20, 2003; Umwelt Medizin Gesellschaft 17:326-332, 2004; J Toxicol Environment Health, Part B 12:572–597, 2009). We are surrounded by numerous electromagnetic fields of variable strength, coming from electronic equipment and its power cords, from high-voltage power lines and from antennas for radio, television and ...

Ultrafine particles from power plants: Evaluation of WRF-Chem simulations with airborne measurements

Science.gov (United States)

Forkel, Renate; Junkermann, Wolfgang

2017-04-01

Ultrafine particles (UFP, particles with a diameter risk to human health and have a potential effect on climate as their presence affects the number concentration of cloud condensation nuclei. Despite of the possibly hazardous effects no regulations exist for this size class of ambient air pollution particles. While ground based continuous measurements of UFP are performed in Germany at several sites (e.g. the German Ultrafine Aerosol Network GUAN, Birmili et al. 2016, doi:10.5194/essd-8-355-2016) information about the vertical distribution of UFP within the atmospheric boundary layer is only scarce. This gap has been closed during the last years by regional-scale airborne surveys for UFP concentrations and size distributions over Germany (Junkermann et al., 2016, doi: 10.3402/tellusb.v68.29250) and Australia (Junkermann and Hacker, 2015, doi: 10.3402/tellusb.v67.25308). Power stations and refineries have been identified as a major source of UFP in Germany with observed particle concentrations > 50000 particles cm-3 downwind of these elevated point sources. Nested WRF-Chem simulations with 2 km grid width for the innermost domain are performed with UFP emission source strengths derived from the measurements in order to study the advection and vertical exchange of UFP from power plants near the Czech and Polish border and their impact on planetary boundary layer particle patterns. The simulations are evaluated against the airborne observations and the downward mixing of the UFP from the elevated sources is studied.

Mercury in tunas and blue marlin in the North Pacific Ocean.

Science.gov (United States)

Drevnick, Paul E; Brooks, Barbara A

2017-05-01

Models and data from the North Pacific Ocean indicate that mercury concentrations in water and biota are increasing in response to (global or hemispheric) anthropogenic mercury releases. In the present study, we provide an updated record of mercury in yellowfin tuna (Thunnus albacares) caught near Hawaii that confirms an earlier conclusion that mercury concentrations in these fish are increasing at a rate similar to that observed in waters shallower than 1000 m. We also compiled and reanalyzed data from bigeye tuna (Thunnus obesus) and blue marlin (Makaira nigricans) caught near Hawaii in the 1970s and 2000s. Increases in mercury concentrations in bigeye tuna are consistent with the trend found in yellowfin tuna, in both timing and magnitude. The data available for blue marlin do not allow for a fair comparison among years, because mercury concentrations differ between sexes for this species, and sex was identified (or reported) in only 3 of 7 studies. Also, mercury concentrations in blue marlin may be insensitive to modest changes in mercury exposure, because this species appears to have the ability to detoxify mercury. The North Pacific Ocean is a region of both relatively high rates of atmospheric mercury deposition and capture fisheries production. Other data sets that allow temporal comparisons in mercury concentrations, such as pacific cod (Gadus macrocephalus) in Alaskan waters and albacore tuna (Thunnus alalunga) off the US Pacific coast, should be explored further, to aid in understanding human health and ecological risks and to develop additional baseline knowledge for assessing changes in a region expected to respond strongly to reductions in anthropogenic mercury emissions. Environ Toxicol Chem 2017;36:1365-1374. © 2017 SETAC. © 2017 SETAC.

New promising antifouling agent based on polymeric biocide polyhexamethylene guanidine molybdate.

Science.gov (United States)

Protasov, Alexander; Bardeau, Jean-Francois; Morozovskaya, Irina; Boretska, Mariia; Cherniavska, Tetiana; Petrus, Lyudmyla; Tarasyuk, Oksana; Metelytsia, Larisa; Kopernyk, Iryna; Kalashnikova, Larisa; Dzhuzha, Oleg; Rogalsky, Sergiy

2017-09-01

A new polymeric biocide polyhexamethylene guanidine (PHMG) molybdate has been synthesized. The obtained cationic polymer has limited water solubility of 0.015 g/100 mL and is insoluble in paint solvents. The results of acute toxicity studies indicate moderate toxicity of PHMG molybdate, which has a median lethal dose at 48 h of 0.7 mg/L for Daphnia magna and at 96 h of 17 mg/L for Danio rerio (zebrafish) freshwater model organisms. Commercial ship paint was then modified by the addition of a low concentration of polymeric biocide 5% (w/w). The painted steel panels were kept in Dnipro River water for the evaluation of the dynamics of fouling biomass. After 129-d exposure, Bryozoa dominated in biofouling of tested substrates, forming 86% (649 g/m 2 ) of the total biomass on control panel surfaces. However, considerably lower Bryozoa fouling biomass (15 g/m 2 ) was detected for coatings containing PHMG molybdate. Dreissenidae mollusks were found to form 88% (2182 g/m 2 ) of the fouling biomass on the control substrates after 228 d of exposure, whereas coatings containing PHMG molybdate showed a much lower biomass value of 23.6 g/m 2 . The leaching rate of PHMG molybdate in water was found to be similar to rates for conventional booster biocides ranging from 5.7 μg/cm 2 /d at the initial stage to 2.2 μg/cm 2 /d at steady state. Environ Toxicol Chem 2017;36:2543-2551. © 2017 SETAC. © 2017 SETAC.

Comparative copper sensitivity between life stages of common subantarctic marine invertebrates.

Science.gov (United States)

Holan, Jessica R; King, Catherine K; Davis, Andrew R

2018-03-01

The development of environmental guidelines in the Antarctic and subantarctic is essential, because expansion of research, tourism, and fishing is placing these regions at increasing risk of contamination. Data are currently insufficient to create the region-specific guidelines needed for the unique conditions in these areas. To develop the most appropriate environmental guidelines, data from the most sensitive life stages of a species should be included to ensure effective protection throughout its life cycle. It is generally accepted that early life stages are more sensitive to contaminants. We compared the toxicity of copper between juvenile and adult life stages of 4 subantarctic marine invertebrates using sublethal and lethal endpoints. For 2 of the species tested, juveniles were more sensitive than adults. (The 7-d median effect concentration [EC50] values for the gastropod Laevilittorina caliginosa were 79 μg/L at the juvenile stage and 125 μg/L at the adult; for the flatworm Obrimoposthia ohlini, values were 190 μg/L at the juvenile stage and 300 μg/L at the adult.) For the isopod Limnoria stephenseni, juveniles were either more sensitive or of equal sensitivity to adults (7-d EC50 values: juvenile 278 μg/L and adult 320 μg/L). In contrast, for the bivalve Gaimardia trapesina, adults appeared to be more sensitive than young adults (7-d EC50 values: juvenile 23 μg/L and adult life history stages was observed, the present study contributes important information for the development of water quality guidelines in polar regions. Environ Toxicol Chem 2018;37:807-815. © 2017 SETAC. © 2017 SETAC.

Spatial and temporal trends and flow dynamics of glyphosate and other pesticides within an agricultural watershed in Argentina.

Science.gov (United States)

Pérez, Débora J; Okada, Elena; De Gerónimo, Eduardo; Menone, Mirta L; Aparicio, Virginia C; Costa, José L

2017-12-01

In the present study, we evaluated the spatial and temporal trends of current-use pesticides in surface water and sediments as well as their relationship with hydrological stream dynamics within the agricultural watershed of El Crespo stream (Buenos Aires Province, Argentina). We sampled 2 contrasting sites: site 1 (upstream), surrounded by agricultural lands, and site 2 (downstream), surrounded by natural grasslands. Most of the applied pesticides (glyphosate, 2,4-D, atrazine, tebuconazole, and imidacloprid) were detected at high frequencies in surface water samples at both sites. However, only glyphosate and aminomethylphosphonic acid (AMPA) were present at high concentrations and had a significant spatial-temporal trend. The highest concentrations were found during spring 2014 at site 1, in association with the intense rains that occurred in that season. The fact that glyphosate and AMPA concentrations were higher than the rest of the studied compounds is closely related to the land use within the watershed, as glyphosate was the most applied herbicide during the fallow period of glyphosate-resistant crops (soybean, maize). The pesticide mixture had a significant spatial-temporal trend, reaching the highest levels during storm flow events in spring 2014. The intensive rains in spring 2014 could be the main factor influencing stream hydrology and pesticide behavior at El Crespo watershed. The estimated annual pesticide losses were 3.11 g/ha at site 1 and 0.72 g/ha at site 2. This result indicates that an attenuation process could be decreasing pesticide loads during downstream transport from site 1 to site 2. Environ Toxicol Chem 2017;36:3206-3216. © 2017 SETAC. © 2017 SETAC.

High-resolution mass spectrometry of skin mucus for monitoring physiological impacts and contaminant biotransformation products in fathead minnows exposed to wastewater effluent.

Science.gov (United States)

Mosley, Jonathan D; Ekman, Drew R; Cavallin, Jenna E; Villeneuve, Daniel L; Ankley, Gerald T; Collette, Timothy W

2018-03-01

High-resolution mass spectrometry is advantageous for monitoring physiological impacts and contaminant biotransformation products in fish exposed to complex wastewater effluent. We evaluated this technique using skin mucus from male and female fathead minnows (Pimephales promelas) exposed to control water or treated wastewater effluent at 5, 20, and 100% levels for 21 d, using an on-site, flow-through system providing real-time exposure. Both sex-specific and non-sex-specific responses were observed in the mucus metabolome, the latter suggesting the induction of general compensatory pathways for xenobiotic exposures. Altogether, 85 statistically significant treatment-dependent metabolite changes were observed out of the 310 total endogenous metabolites that were detected (156 of the 310 were annotated). Partial least squares-regression models revealed strong covariances between the mucus metabolomes and up-regulated hepatic messenger ribonucleic acid (mRNA) transcripts reported previously for these same fish. These regression models suggest that mucus metabolomic changes reflected, in part, processes by which the fish biotransformed xenobiotics in the effluent. In keeping with this observation, we detected a phase II transformation product of bisphenol A in the skin mucus of male fish. Collectively, these findings demonstrate the utility of mucus as a minimally invasive matrix for simultaneously assessing exposures and effects of environmentally relevant mixtures of contaminants. Environ Toxicol Chem 2018;37:788-796. Published 2017 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2017 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Response and recovery of the macrophytes Elodea canadensis and Myriophyllum spicatum following a pulse exposure to the herbicide iofensulfuron-sodium in outdoor stream mesocosms.

Science.gov (United States)

Wieczorek, Matthias V; Bakanov, Nikita; Lagadic, Laurent; Bruns, Eric; Schulz, Ralf

2017-04-01

Interest in stream mesocosms has recently revived for higher tier aquatic macrophyte risk assessment of plant protection products mainly because 1) the highest predicted environmental concentrations for the assessment of effects are frequently derived from stream scenarios, and 2) they allow an effect assessment using stream-typical pulse exposures. Therefore, the present stream mesocosm study used an herbicide pulse exposure and evaluated the responses of Elodea canadensis and Myriophyllum spicatum. Macrophytes were exposed for 24 h to 1 μg/L, 3 μg/L, 10 μg/L, and 30 μg/L of the herbicide iofensulfuron-sodium with a subsequent recovery period of 42 d. Biological endpoints were growth rates of the main, side, and total shoot length, the shoot number, the maximum root length, and the dry weight. The total shoot length was identified as the most sensitive endpoint; the growth rate of the total shoot length was inhibited by up to 66% and 45% in M. spicatum and E. canadensis, respectively. The lowest no observed effect concentrations (NOECs) were observed at day 7 and/or day 14 after herbicide treatment and were 1 μg/L for M. spicatum and 3 μg/L for E. canadensis. The no-observed-ecologically-adverse-effect concentrations (NOEAECs) were 10 μg/L and 30 μg/L for M. spicatum and E. canadensis, respectively. Such or similar mesocosm designs are useful to simulate typical stream exposures and estimate herbicide effects on aquatic macrophytes in stream systems. Environ Toxicol Chem 2017;36:1090-1100. © 2016 SETAC. © 2016 SETAC.

Silver nanoparticles and dissolved silver activate contrasting immune responses and stress-induced heat shock protein expression in sea urchin.

Science.gov (United States)

Magesky, Adriano; de Oliveira Ribeiro, Ciro A; Beaulieu, Lucie; Pelletier, Émilien

2017-07-01

Using immune cells of sea urchin Strongylocentrotus droebachiensis in early development as a model, the cellular protective mechanisms against ionic and poly(allylamine)-coated silver nanoparticle (AgNPs; 14 ± 6 nm) treatments at 100 μg L -1 were investigated. Oxidative stress, heat shock protein expression, and pigment production by spherulocytes were determined as well as AgNP translocation pathways and their multiple effects on circulating coelomocytes. Sea urchins showed an increasing resilience to Ag over time because ionic Ag is accumulated in a steady way, although nanoAg levels dropped between 48 h and 96 h. A clotting reaction emerged on tissues injured by dissolved Ag (present as chloro-complexes in seawater) between 12 h and 48 h. Silver contamination and nutritional state influenced the production of reactive oxygen species. After passing through coelomic sinuses and gut, AgNPs were found in coelomocytes. Inside blood vessels, apoptosis-like processes appeared in coelomocytes highly contaminated by poly(allylamine)-coated AgNPs. Increasing levels of Ag accumulated by urchins once exposed to AgNPs pointed to a Trojan-horse mechanism operating over 12-d exposure. However, under short-term treatments, physical interactions of poly(allylamine)-coated AgNPs with cell structures might be, at some point, predominant and responsible for the highest levels of stress-related proteins detected. The present study is the first report detailing nano-translocation in a marine organism and multiple mechanisms by which sea urchin cells can deal with toxic AgNPs. Environ Toxicol Chem 2017;36:1872-1886. © 2016 SETAC. © 2016 SETAC.

Egg-laying sequence influences egg mercury concentrations and egg size in three bird species: Implications for contaminant monitoring programs.

Science.gov (United States)

Ackerman, Joshua T; Eagles-Smith, Collin A; Herzog, Mark P; Yee, Julie L; Hartman, C Alex

2016-06-01

Bird eggs are commonly used in contaminant monitoring programs and toxicological risk assessments, but intraclutch variation and sampling methodology could influence interpretability. The authors examined the influence of egg-laying sequence on egg mercury concentrations and burdens in American avocets, black-necked stilts, and Forster's terns. The average decline in mercury concentrations between the first and last eggs laid was 33% for stilts, 22% for terns, and 11% for avocets, and most of this decline occurred between the first and second eggs laid (24% for stilts, 18% for terns, and 9% for avocets). Trends in egg size with egg-laying order were inconsistent among species, and overall differences in egg volume, mass, length, and width were eggs laid. Despite the strong effect of egg-laying sequence, most of the variance in egg mercury concentrations still occurred among clutches (75-91%) rather than within clutches (9%-25%). Using simulations, the authors determined that accurate estimation of a population's mean egg mercury concentration using only a single random egg from a subset of nests would require sampling >60 nests to represent a large population (10% accuracy) or ≥14 nests to represent a small colony that contained <100 nests (20% accuracy). Environ Toxicol Chem 2016;35:1458-1469. Published 2015 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America. Published 2015 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America.

Refinement and cross-validation of nickel bioavailability in PNEC-Pro, a regulatory tool for site-specific risk assessment of metals in surface water.

Science.gov (United States)

Verschoor, Anja J; Vijver, Martina G; Vink, Jos P M

2017-09-01

The European Water Framework Directive prescribes that the environmental quality standards for nickel in surface waters should be based on bioavailable concentrations. Biotic ligand models (BLMs) are powerful tools to account for site-specific bioavailability within risk assessments. Several BLMs and simplified tools are available. For nickel, most of them are based on the same toxicity dataset and chemical speciation methodology as laid down in the 2008 European Union Environmental Risk Assessment Report (RAR). Since then, further insights into the toxic effects of nickel on aquatic species have been gained, and new data and methodologies have been generated and implemented using the predicted-no-effect-concentration (PNEC)-pro tool. The aim of the present study is to provide maximum transparency on data revisions and how this affects the derived environmental quality standards. A case study with 7 different ecoregions was used to determine differences in species sensitivity distributions and in hazardous concentrations for 5% of the species (HC5) values between the original Ni-RAR BLMs and the PNEC-pro BLMs. The BLM parameters used were pH dependent, which extended the applicability domain of PNEC-pro up to a pH of 8.7 for surface waters. After inclusion of additional species and adjustment for cross-species extrapolation, the HC5s were well within the prediction range of the RAR. Based on the latest data and scientific insights, transfer functions in the user-friendly PNEC-pro tool have been updated accordingly without compromising the original considerations of the Ni-RAR. Environ Toxicol Chem 2017;36:2367-2376. © 2017 SETAC. © 2017 SETAC.

Modeling chemical accumulation in sediment of small waterbodies accounting for sediment transport and water-sediment exchange processes over long periods.

Science.gov (United States)

Patterson, David Albert; Strehmel, Alexander; Erzgräber, Beate; Hammel, Klaus

2017-12-01

In a recent scientific opinion of the European Food Safety Authority it is argued that the accumulation of plant protection products in sediments over long time periods may be an environmentally significant process. Therefore, the European Food Safety Authority proposed a calculation to account for plant protection product accumulation. This calculation, however, considers plant protection product degradation within sediment as the only dissipation route, and does not account for sediment dynamics or back-diffusion into the water column. The hydraulic model Hydrologic Engineering Center-River Analysis System (HEC-RAS; US Army Corps of Engineers) was parameterized to assess sediment transport and deposition dynamics within the FOrum for Co-ordination of pesticide fate models and their USe (FOCUS) scenarios in simulations spanning 20 yr. The results show that only 10 to 50% of incoming sediment would be deposited. The remaining portion of sediment particles is transported across the downstream boundary. For a generic plant protection product substance this resulted in deposition of only 20 to 50% of incoming plant protection product substance. In a separate analysis, the FOCUS TOXSWA model was utilized to examine the relative importance of degradation versus back-diffusion as loss processes from the sediment compartment for a diverse range of generic plant protection products. In simulations spanning 20 yr, it was shown that back-diffusion was generally the dominant dissipation process. The results of the present study show that sediment dynamics and back-diffusion should be considered when calculating long-term plant protection product accumulation in sediment. Neglecting these may lead to a systematic overestimation of accumulation. Environ Toxicol Chem 2017;36:3223-3231. © 2017 SETAC. © 2017 SETAC.

Assessment of the toxic effect of pesticides on honey bee drone fertility using laboratory and semifield approaches: A case study of fipronil.

Science.gov (United States)

Kairo, Guillaume; Poquet, Yannick; Haji, Haïthem; Tchamitchian, Sylvie; Cousin, Marianne; Bonnet, Marc; Pelissier, Michel; Kretzschmar, André; Belzunces, Luc P; Brunet, Jean-Luc

2017-09-01

Concern about the reproductive toxicity of plant protection products in honey bee reproducers is increasing. Because the reproductive capacity of honey bees is not currently considered during the risk assessment procedure performed during plant protection product registration, it is important to provide methods to assess such potential impairments. To achieve this aim, we used 2 different approaches that involved semifield and laboratory conditions to study the impact of fipronil on drone fertility. For each approach, the drones were reared for 20 d, from emergence to sexual maturity, and exposed to fipronil via a contaminated sugar solution. In both groups, the effects of fipronil were determined by studying life traits and fertility indicators. The results showed that the survival and maturity rates of the drones were better under laboratory conditions than under semifield conditions. Moreover, the drones reared under laboratory conditions produced more seminal fluid. Although these differences could be explained by environmental factors that may vary under semifield conditions, it was found that regardless of the approach used, fipronil did not affect survival rates, maturity rates, or semen volumes, whereas it did affect fertility by inducing a decrease in spermatozoa quantity that was associated with an increase in spermatozoa mortality. These results confirm that fipronil affects drone fertility and support the relevance of each approach for assessing the potential reproductive toxicity of plant protection products in honey bees. Environ Toxicol Chem 2017;36:2345-2351. © 2017 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC. © 2017 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

The comet assay in Folsomia candida: A suitable approach to assess genotoxicity in collembolans.

Science.gov (United States)

Cardoso, Diogo N; Silva, Ana Rita R; Cruz, Andreia; Lourenço, Joana; Neves, Joana; Malheiro, Catarina; Mendo, Sónia; Soares, Amadeu M V M; Loureiro, Susana

2017-09-01

The present study shows the comet assay technique being successfully applied for the first time to one of the most widely used soil organisms in standardized ecotoxicological tests, Folsomia candida, providing a step forward in assessing the genotoxicity induced by xenobiotics. Because collembolans have a high content of chitin, a new methodology was developed in which the heads of the collembolans were separated from the rest of the body, allowing the hemolymph to leak out. This procedure allows the cells to be released, and after lysis the genetic material is available for the comet assay. Among other key procedures, the use of 30 organisms (20- to 22-d-old adults) per replicate and the correct amount of cells with genetic material (translated as 10 μL of suspension) applied on the agarose gel were determinants for the success of the results obtained. The methodology was validated by exposing F. candida to a representative metallic element (cadmium) and a representative of organophosphates, the insecticide dimethoate, for a shorter time period of 10 d, compared with the 28 d for the International Organization for Standardization 11267 method. Within this method, the relatively low percentage of DNA damage (30%) observed in controls and the significant increase in terms of percentage of DNA damage for almost all the concentrations of dimethoate and Cd (reaching 52% and 56% of damage in the highest concentrations, respectively) confirmed the genotoxic effect of both compounds and validated this technique. The comet assay proved to be a sensitive technique to detect DNA strand breaks in collembolans' cells. Environ Toxicol Chem 2017;36:2514-2520. © 2017 SETAC. © 2017 SETAC.

Assessing and managing multiple risks in a changing world-The Roskilde recommendations.

Science.gov (United States)

Selck, Henriette; Adamsen, Peter B; Backhaus, Thomas; Banta, Gary T; Bruce, Peter K H; Burton, G Allen; Butts, Michael B; Boegh, Eva; Clague, John J; Dinh, Khuong V; Doorn, Neelke; Gunnarsson, Jonas S; Hauggaard-Nielsen, Henrik; Hazlerigg, Charles; Hunka, Agnieszka D; Jensen, John; Lin, Yan; Loureiro, Susana; Miraglia, Simona; Munns, Wayne R; Nadim, Farrokh; Palmqvist, Annemette; Rämö, Robert A; Seaby, Lauren P; Syberg, Kristian; Tangaa, Stine R; Thit, Amalie; Windfeld, Ronja; Zalewski, Maciej; Chapman, Peter M

2017-01-01

Roskilde University (Denmark) hosted a November 2015 workshop, Environmental Risk-Assessing and Managing Multiple Risks in a Changing World. This Focus article presents the consensus recommendations of 30 attendees from 9 countries regarding implementation of a common currency (ecosystem services) for holistic environmental risk assessment and management; improvements to risk assessment and management in a complex, human-modified, and changing world; appropriate development of protection goals in a 2-stage process; dealing with societal issues; risk-management information needs; conducting risk assessment of risk management; and development of adaptive and flexible regulatory systems. The authors encourage both cross-disciplinary and interdisciplinary approaches to address their 10 recommendations: 1) adopt ecosystem services as a common currency for risk assessment and management; 2) consider cumulative stressors (chemical and nonchemical) and determine which dominate to best manage and restore ecosystem services; 3) fully integrate risk managers and communities of interest into the risk-assessment process; 4) fully integrate risk assessors and communities of interest into the risk-management process; 5) consider socioeconomics and increased transparency in both risk assessment and risk management; 6) recognize the ethical rights of humans and ecosystems to an adequate level of protection; 7) determine relevant reference conditions and the proper ecological context for assessments in human-modified systems; 8) assess risks and benefits to humans and the ecosystem and consider unintended consequences of management actions; 9) avoid excessive conservatism or possible underprotection resulting from sole reliance on binary, numerical benchmarks; and 10) develop adaptive risk-management and regulatory goals based on ranges of uncertainty. Environ Toxicol Chem 2017;36:7-16. © 2016 SETAC. © 2016 SETAC.

Long-term effects of sulfidized silver nanoparticles in sewage sludge on soil microflora.

Science.gov (United States)

Kraas, Marco; Schlich, Karsten; Knopf, Burkhard; Wege, Franziska; Kägi, Ralf; Terytze, Konstantin; Hund-Rinke, Kerstin

2017-12-01

The use of silver nanoparticles (AgNPs) in consumer products such as textiles leads to their discharge into wastewater and consequently to a transfer of the AgNPs to soil ecosystems via biosolids used as fertilizer. In urban wastewater systems (e.g., sewer, wastewater treatment plant [WWTP], anaerobic digesters) AgNPs are efficiently converted into sparingly soluble silver sulfides (Ag 2 S), mitigating the toxicity of the AgNPs. However, long-term studies on the bioavailability and effects of sulfidized AgNPs on soil microorganisms are lacking. Thus we investigated the bioavailability and long-term effects of AgNPs (spiked in a laboratory WWTP) on soil microorganisms. Before mixing the biosolids into soil, the sludges were either anaerobically digested or directly dewatered. The effects on the ammonium oxidation process were investigated over 140 d. Transmission electron microscopy (TEM) suggested an almost complete sulfidation of the AgNPs analyzed in all biosolid samples and in soil, with Ag 2 S predominantly detected in long-term incubation experiments. However, despite the sulfidation of the AgNPs, soil ammonium oxidation was significantly inhibited, and the degree of inhibition was independent of the sludge treatment. The results revealed that AgNPs sulfidized under environmentally relevant conditions were still bioavailable to soil microorganisms. Consequently, Ag 2 S may exhibit toxic effects over the long term rather than the short term. Environ Toxicol Chem 2017;36:3305-3313. © 2017 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC. © 2017 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC.

Modeling the effect of water chemistry on the bioaccumulation of waterborne cadmium in zebra mussels.

Science.gov (United States)

Bourgeault, Adeline; Gourlay-Francé, Catherine; Tusseau-Vuillemin, Marie-Hélène

2010-10-01

The present study aims at investigating the effects of Zn, Ca, and dissolved organic carbon (DOC) on the waterborne Cd bioaccumulation of a freshwater bivalve (Dreissena polymorpha). Mussels were exposed for 48 h at 3 µg/L of Cd in different media. Their physiological activities were assessed by separately measuring the filtration rate in the same exposure water. Increased Zn (from 3 to 89 µg/L) and Ca (from 37 to 131 mg/L) concentrations in water led to a threefold and sevenfold reduction of Cd bioaccumulation, whereas the effect of DOC varied greatly depending on its concentration. At low DOC concentrations (from 0.2 to 1.1 mg/L), the uptake of Cd increased, whereas at higher concentrations (from 1.1 to 17.1 mg/L), the uptake decreased. The filtration activity was not strongly influenced by either Zn or Ca concentration, whereas it was modified in enriched DOC media in the same manner as Cd uptake. A competitive model was built to predict the waterborne uptake rate constant of Cd (k (u)) as a function of Zn and Ca concentrations in the water. Over the range of DOC concentrations we tested, organic matter was shown to influence Cd bioaccumulation in two ways: by modifying Cd speciation and thus its bioavailability and its interaction with the biological membrane, and by affecting the mussel's physiology and therefore its sensitivity to metal. The present study provides a useful means of adjusting the toxicokinetic constant to the water's physicochemical characteristics and proposes a unifying model that takes into account the different geochemical and biological influences on bioaccumulation. Environ. Toxicol. Chem. 2010;29:2182-2189. © 2010 SETAC.

A comparison of four porewater sampling methods for metal mixtures and dissolved organic carbon and the implications for sediment toxicity evaluations.

Science.gov (United States)

Cleveland, Danielle; Brumbaugh, William G; MacDonald, Donald D

2017-11-01

Evaluations of sediment quality conditions are commonly conducted using whole-sediment chemistry analyses but can be enhanced by evaluating multiple lines of evidence, including measures of the bioavailable forms of contaminants. In particular, porewater chemistry data provide information that is directly relevant for interpreting sediment toxicity data. Various methods for sampling porewater for trace metals and dissolved organic carbon (DOC), which is an important moderator of metal bioavailability, have been employed. The present study compares the peeper, push point, centrifugation, and diffusive gradients in thin films (DGT) methods for the quantification of 6 metals and DOC. The methods were evaluated at low and high concentrations of metals in 3 sediments having different concentrations of total organic carbon and acid volatile sulfide and different particle-size distributions. At low metal concentrations, centrifugation and push point sampling resulted in up to 100 times higher concentrations of metals and DOC in porewater compared with peepers and DGTs. At elevated metal levels, the measured concentrations were in better agreement among the 4 sampling techniques. The results indicate that there can be marked differences among operationally different porewater sampling methods, and it is unclear if there is a definitive best method for sampling metals and DOC in porewater. Environ Toxicol Chem 2017;36:2906-2915. Published 2017 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2017 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Differential uptake of gold nanoparticles by 2 species of tadpole, the wood frog (Lithobates sylvaticus) and the bullfrog (Lithobates catesbeianus).

Science.gov (United States)

Thompson, Lucas B; Carfagno, Gerardo L F; Andresen, Kurt; Sitton, Andrea J; Bury, Taylor; Lee, Laura L; Lerner, Kevin T; Fong, Peter P

2017-12-01

Engineered nanoparticles are aquatic contaminants of emerging concern that exert ecotoxicological effects on a wide variety of organisms. We exposed cetyltrimethylammonium bromide-capped spherical gold nanoparticles to wood frog and bullfrog tadpoles with conspecifics and in combination with the other species continuously for 21 d, then measured uptake and localization of gold. Wood frog tadpoles alone and in combination with bullfrog tadpoles took up significantly more gold than bullfrogs. Bullfrog tadpoles in combination with wood frogs took up significantly more gold than controls. The rank order of weight-normalized gold uptake was wood frogs in combination > wood frogs alone > bullfrogs in combination > bullfrogs alone > controls. In all gold-exposed groups of tadpoles, gold was concentrated in the anterior region compared with the posterior region of the body. The concentration of gold nanoparticles in the anterior region of wood frogs both alone and in combination with bullfrogs was significantly higher than the corresponding posterior regions. We also measured depuration time of gold in wood frogs. After 21 d in a solution of gold nanoparticles, tadpoles lost >83% of internalized gold when placed in gold-free water for 5 d. After 10 d in gold-free water, tadpoles lost 94% of their gold. After 15 d, gold concentrations were below the level of detection. Our finding of differential uptake between closely related species living in similar habitats with overlapping geographical distributions argues against generalizing toxicological effects of nanoparticles for a large group of organisms based on measurements in only one species. Environ Toxicol Chem 2017;36:3351-3358. © 2017 SETAC. © 2017 SETAC.

Review of titanium dioxide nanoparticle phototoxicity: Developing a phototoxicity ratio to correct the endpoint values of toxicity tests

Science.gov (United States)

2015-01-01

Abstract Titanium dioxide nanoparticles are photoactive and produce reactive oxygen species under natural sunlight. Reactive oxygen species can be detrimental to many organisms, causing oxidative damage, cell injury, and death. Most studies investigating TiO2 nanoparticle toxicity did not consider photoactivation and performed tests either in dark conditions or under artificial lighting that did not simulate natural irradiation. The present study summarizes the literature and derives a phototoxicity ratio between the results of nano‐titanium dioxide (nano‐TiO2) experiments conducted in the absence of sunlight and those conducted under solar or simulated solar radiation (SSR) for aquatic species. Therefore, the phototoxicity ratio can be used to correct endpoints of the toxicity tests with nano‐TiO2 that were performed in absence of sunlight. Such corrections also may be important for regulators and risk assessors when reviewing previously published data. A significant difference was observed between the phototoxicity ratios of 2 distinct groups: aquatic species belonging to order Cladocera, and all other aquatic species. Order Cladocera appeared very sensitive and prone to nano‐TiO2 phototoxicity. On average nano‐TiO2 was 20 times more toxic to non‐Cladocera and 1867 times more toxic to Cladocera (median values 3.3 and 24.7, respectively) after illumination. Both median value and 75% quartile of the phototoxicity ratio are chosen as the most practical values for the correction of endpoints of nano‐TiO2 toxicity tests that were performed in dark conditions, or in the absence of sunlight. Environ Toxicol Chem 2015;34:1070–1077. © 2015 The Author. Published by SETAC. PMID:25640001

RNA sequencing analysis of transcriptional change in the freshwater mussel Elliptio complanata after environmentally relevant sodium chloride exposure.

Science.gov (United States)

Robertson, Laura S; Galbraith, Heather S; Iwanowicz, Deborah; Blakeslee, Carrie J; Cornman, R Scott

2017-09-01

To identify potential biomarkers of salt stress in a freshwater sentinel species, we examined transcriptional responses of the common mussel Elliptio complanata to controlled sodium chloride (NaCl) exposures. Ribonucleic acid sequencing (RNA-Seq) of mantle tissue identified 481 transcripts differentially expressed in adult mussels exposed to 2 ppt NaCl (1.2 ppt chloride) for 7 d, of which 290 had nonoverlapping intervals. Differentially expressed gene categories included ion and transmembrane transport, oxidoreductase activity, maintenance of protein folding, and amino acid metabolism. The rate-limiting enzyme for synthesis of taurine, an amino acid frequently linked to osmotic stress in aquatic species, was upregulated, as was the transmembrane ion pump sodium/potassium adenosine 5'-triphosphatase. These patterns confirm a primary transcriptional response to the experimental dose, albeit likely overlapping with nonspecific secondary stress responses. Substantial involvement of the heat shock protein 70 chaperone family and the water-transporting aquaporin family was not detected, however, in contrast to some studies in other bivalves. A subset of the most significantly regulated genes was confirmed by quantitative polymerase chain reaction in an independent sample. Cluster analysis showed separation of mussels exposed to 2 ppt NaCl from control mussels in multivariate space, but mussels exposed to 1 ppt NaCl were largely indistinguishable from controls. Transcriptome-scale analysis of salt exposure under laboratory conditions efficiently identified candidate biomarkers for further functional analysis and field validation. Environ Toxicol Chem 2017;36:2352-2366. © Published 2017 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. © 2017 SETAC.

Intersex and liver alterations induced by long-term sublethal exposure to 17α-ethinylestradiol in adult male Cnesterodon decemmaculatus (Pisces: Poeciliidae).

Science.gov (United States)

Young, Brian Jonathan; López, Gabriela Carina; Cristos, Diego Sebastián; Crespo, Diana Cristina; Somoza, Gustavo Manuel; Carriquiriborde, Pedro

2017-07-01

The aim of the present study was to assess the responses of the gonopodium morphology and the gonadal and liver histology of adult male Cnesterodon decemmaculatus to sublethal long-term exposure concentrations of 17α-ethinylestradiol (EE2). Two experiments were conducted exposing the fish to waterborne concentrations of EE2 ranging from 20 ng/L to 200 ng/L for 8 wk, 12 wk, and 16 wk. Intersex gonads were observed after 8 wk and 16 wk in fish exposed to 200 ng EE2/L and 100 ng EE2/L, respectively. Oocytes' development from testis germ cells and replacement of the efferent duct periodic acid-Schiff-positive secretion surrounding spermatozeugmata by parenchymal tissue and duct structure alterations were the major observed changes in the gonads. In contrast, no response was observed in the gonopodium morphology. Liver histology was also altered, showing increasing steatosis, single-cell necrosis to generalized necrosis, and disruption of acinar organization from 100 ng EE2/L to 200 ng EE2/L. In summary, the present results showed that although EE2 was not able to alter the morphology of a developed gonopodium, it was capable of inducing development of testicular oocytes in adult male C. decemmaculatus at environmentally relevant concentrations. Thus, externally normal but intersex C. decemmaculatus males would be expected in the wastewater-receiving streams that the species inhabits. According to the literature, the present study would be the first indicating estrogen-induced intersex in adult male poeciliid. Environ Toxicol Chem 2017;36:1738-1745. © 2016 SETAC. © 2016 SETAC.

Increased polycyclic aromatic hydrocarbon toxicity following their photomodification in natural sunlight: impacts on the duckweed Lemna gibba L. G-3

International Nuclear Information System (INIS)

Huang, X.D.; Dixon, D.G.; Greenberg, B.M.

1995-01-01

The authors previously demonstrated that simulated solar radiation (SSR), with a fluence rate of only 40 mumol m -2 sec -1 , increased polycyclic aromatic hydrocarbon (PAH) toxicity to the duckweed Lemna gibba and that PAHs photomodified in SSR (generally oxygenation of the ring system) are more toxic than the parent compounds (Huang et al., Environ. Toxicol. Chem., 1993, 12, 1067-1077). It is not known, however, to what extent toxicity of PAHs can increase due to photomodification. Thus, natural sunlight, which has a high fluence rate (approximately 2000 mumol m -2 sec -1 ), was used to photomodify anthracene, benzo[a]pyrene, fluoranthene, phenanthrene, and pyrene. Toxicity was based on growth inhibition of L. gibba, measured as the rate of production of new leaves over an 8-day period. Initially, the toxicity of the PAHs applied in intact form was probed, with the compounds demonstrating greater toxicity in sunlight than in SSR. Next the PAHs were photomodified in sunlight prior to incubation with the plants. The half-lives of the PAHs in sunlight ranged from 12 min to 30 hr. Although most of the products of PAH photomodification are not yet identified, the degree that PAH toxicity increased following photomodification in sunlight could still be probed. The mixtures of photomodified chemicals that were derived from each PAH in sunlight were applied of L. gibba and growth inhibition under 100 mumol m -2 sec -1 of SSR was determined. The LC50s for the PAH photoproducts generated in sunlight were an order of magnitude lower than the LC50s for the PAHs applied in intact form. (author)

Methylated polycyclic aromatic hydrocarbons and/or their metabolites are important contributors to the overall estrogenic activity of polycyclic aromatic hydrocarbon-contaminated soils.

Science.gov (United States)

Lam, Monika M; Engwall, Magnus; Denison, Michael S; Larsson, Maria

2018-02-01

In the present study 42 polycyclic aromatic compounds (PACs) were investigated for their estrogenic potential using the VM7Luc4E2 transactivation assay. Relative potencies were determined for mass-balance analysis. In addition, compounds were tested in combination with the estrogen receptor (ER) antagonist ICI182,780 (ICI) and the aryl hydrocarbon receptor antagonist/CYP1A1 inhibitor α-naphthoflavone. Luciferase induction and CYP1A1-dependent ethoxyresorufin-O-deethylase (EROD) activity were measured to assess whether the estrogenic activity was elicited by the compound itself and/or by its metabolites. Relative potencies ranged between 10 -7 and 10 -4 . The ability of ICI to decrease luciferase activity stimulated by all compounds indicated that the induction responses were ER-dependent. The aryl hydrocarbon receptor antagonist/CYP1A1 inhibitor α-naphthoflavone decreased luciferase induction and EROD activity by several compounds, including the methylated chrysenes, suggesting that metabolites of these chemicals contributed to ER activation. Several PACs, such as acridine and its derivatives, appear to directly activate the ER. Furthermore, extracts of soils from industrial areas were examined using this bioassay, and estrogenic activity was detected in all soil samples. Mass-balance analysis using a combination of relative potencies and chemical analysis of the samples suggested that polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs, such as 1- and 3-methylchrysene, are important contributors to the overall estrogenic activity. However, these results revealed that a considerable proportion of the estrogenic activity in the soil remained unexplained, indicating the presence of other significant estrogenic compounds. Environ Toxicol Chem 2018;37:385-397. © 2017 SETAC. © 2017 SETAC.

Interactions of nickel(II) with histones: enhancement of 2'-deoxyguanosine oxidation by Ni(II) complexes with CH3CO-Cys-Ala-Ile-His-NH2, a putative metal binding sequence of histone H3.

Science.gov (United States)

Bal, W; Lukszo, J; Kasprazak, K S

1996-03-01

Studies of 2'-deoxyguanosine oxidation by hydrogen peroxide in the presence of CH3CO-Cys-Ala-Ile-His-NH2 (CAIH) and/or NiCl2 have been carried out in 100 mM phosphate buffer (pH 7.4) at 37 degrees C. The dimeric CAIH oxidation product, CAIH disulfide, and its weak, octahedral Ni(II) complex, rather than the monomeric CAIH and its strong, square-planar Ni(II) complex, were found to be major catalysts of 8-oxo-2'-deoxyguanosine (8-oxo-dG) formation. The presence of Ni(II) largely enhanced 8-oxo-dG yield, especially at submillimolar concentrations of H2O2. The reaction was found not to involve detectable amounts of free radicals or Ni(III). These results, together with those published previously [Bal, W. et al. (1995) Chem. Res. Toxicol. 8, 683-692], lay a framework for the detailed investigations of the interactions of histone octamer with Ni(II) and other metal ions. They also suggest that molecular mechanisms of nickel carcinogenesis may involve oxidative damage processes catalyzed by weak Ni(II) complexes with cellular components.

Conformations of stereoisomeric base adducts to 4-hydroxyequilenin.

Science.gov (United States)

Ding, Shuang; Shapiro, Robert; Geacintov, Nicholas E; Broyde, Suse

2003-06-01

Exposure to estrogen through estrogen replacement therapy increases the risk of women developing cancer in hormone sensitive tissues. Premarin (Wyeth), which has been the most frequent choice for estrogen replacement therapy in the United States, contains the equine estrogens equilin and equilenin as major components. 4-Hydroxyequilenin (4-OHEN) is a phase I metabolite of both of these substances. This catechol estrogen autoxidizes to potent cytotoxic quinoids that can react with dG, dA, and dC to form unusual stereoisomeric cyclic adducts (Bolton, J. L., et al. (1998) Chem. Res. Toxicol. 11, 1113-1127). Like other bulky DNA adducts, these lesions may exhibit different susceptibilities to DNA repair and mutagenic potential, if not repaired in a structure-dependent manner. To ultimately gain insights into structure-function relationships, we computed conformations of stereoisomeric guanine, adenine, and cytosine base adducts using density functional theory. We find near mirror image conformations in stereoisomer adduct pairs for each modified base, suggesting opposite orientations with respect to the 5' --> 3' direction of the modified strand when the stereoisomer pairs are incorporated into duplex DNA. Such opposite orientations could cause stereoisomer pairs of lesions to respond differently to DNA replication and repair enzymes.

Part I: Reverse-docking studies of a squaramide-catalyzed conjugate addition of a diketone to a nitro-olefin Part II: The development of ChemSort: an education game for organic chemistry

Science.gov (United States)

Granger, Jenna Christine

Part 1: Reverse-docking studies of a squaramide-catalyzed conjugate addition of a diketone to a nitro-olefin. Asymmetric organocatalysis, the catalysis of asymmetric reactions by small organic molecules, is a rapidly growing field within organic synthesis. The ability to rationally design organocatalysts is therefore of increasing interest to organic chemists. Computational chemistry is quickly proving to be an extremely successful method for understanding and predicting the roles of organocatalysts, and therefore is certain to be of use in the rational design of such catalysts. A methodology for reverse-docking flexible organocatalysts to rigid transition state models of asymmetric reactions has been previously developed by the Deslongchamps group. The investigation of Rawal's squaramide-based organocatalyst for the addition of a diketone to a nitro-olefin is described, and the results of the reverse docking of Rawal's catalyst to the geometry optimized transition state models of the uncatalyzed reaction for both the R and S-product enantiomers are presented. The results of this study indicate a preference for binding of the organocatalyst to the R-enantiomer transition state model with a predicted enantiomeric excess of 99%, which is consistent with the experimental results. A plausible geometric model of the transition state for the catalyzed reaction is also presented. The success of this study demonstrates the credibility of using reverse docking methods for the rational design of asymmetric organocatalysts. Part 2: The development of ChemSort: an educational game for organic chemistry. With the advent of the millennial learner, we need to rethink traditional classroom approaches to science learning in terms of goals, approaches, and assessments. Digital simulations and games hold much promise in support of this educational shift. Although the idea of using games for education is not a new one, well-designed computer-based "serious games" are only beginning to

Modeling of low-temperature plasmas generated using laser-induced breakdown spectroscopy: the ChemCam diagnostic tool on the Mars Science Laboratory Rover

Science.gov (United States)

Colgan, James

2016-05-01

We report on efforts to model the low-temperature plasmas generated using laser-induced breakdown spectroscopy (LIBS). LIBS is a minimally invasive technique that can quickly and efficiently determine the elemental composition of a target and is employed in an extremely wide range of applications due to its ease of use and fast turnaround. In particular, LIBS is the diagnostic tool used by the ChemCam instrument on the Mars Science Laboratory rover Curiosity. In this talk, we report on the use of the Los Alamos plasma modeling code ATOMIC to simulate LIBS plasmas, which are typically at temperatures of order 1 eV and electron densities of order 10 16 - 17 cm-3. At such conditions, these plasmas are usually in local-thermodynamic equilibrium (LTE) and normally contain neutral and singly ionized species only, which then requires that modeling must use accurate atomic structure data for the element under investigation. Since LIBS devices are often employed in a very wide range of applications, it is therefore desirable to have accurate data for most of the elements in the periodic table, ideally including actinides. Here, we discuss some recent applications of our modeling using ATOMIC that have explored the plasma physics aspects of LIBS generated plasmas, and in particular discuss the modeling of a plasma formed from a basalt sample used as a ChemCam standard1. We also highlight some of the more general atomic physics challenges that are encountered when attempting to model low-temperature plasmas. The Los Alamos National Laboratory is operated by Los Alamos National Security, LLC for the National Nuclear Security Administration of the U.S. Department of Energy under Contract No. DE-AC5206NA25396. Work performed in conjunction with D. P. Kilcrease, H. M. Johns, E. J. Judge, J. E. Barefield, R. C. Wiens, S. M. Clegg.

Abordagem toxicológica da C

African Journals Online (AJOL)

Muller

reproductive and foetal toxicity, of the ethanol extract from Copaifera luetzelburgii (EEtOH-Cl). In the ... EEtOH-Cl. In the first group, the effect of the extract on the development of pregnancy from first to seventh day was .... Chemicals and drugs.

Abordagem toxicológica da C

African Journals Online (AJOL)

Muller

Full Length Research Paper ... estrogenic activity by increasing the relative weight (%) of the uterus of rats treated at doses of 125, 250 ... assessment of toxicity in pregnancy, the animals were divided into two groups and treated daily with.

NAD(P)H:quinone oxidoreductase expression in Cyp1a-knockout and CYP1A-humanized mouse lines and its effect on bioactivation of the carcinogen aristolochic acid I

Energy Technology Data Exchange (ETDEWEB)

Levova, Katerina; Moserova, Michaela [Department of Biochemistry, Faculty of Science, Charles University, Prague (Czech Republic); Nebert, Daniel W. [Department of Environmental Health, University of Cincinnati Medical Center, Cincinnati (United States); Phillips, David H. [Analytical and Environmental Sciences Division, MRC-HPA Centre for Environment and Health, King' s College London, London (United Kingdom); Frei, Eva [Division of Preventive Oncology, National Center for Tumor Diseases, German Cancer Research Center (DKFZ), Heidelberg (Germany); Schmeiser, Heinz H. [Research Group Genetic Alterations in Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg (Germany); Arlt, Volker M. [Analytical and Environmental Sciences Division, MRC-HPA Centre for Environment and Health, King' s College London, London (United Kingdom); Stiborova, Marie, E-mail: stiborov@natur.cuni.cz [Department of Biochemistry, Faculty of Science, Charles University, Prague (Czech Republic)

2012-12-15

Aristolochic acid causes a specific nephropathy (AAN), Balkan endemic nephropathy, and urothelial malignancies. Using Western blotting suitable to determine protein expression, we investigated in several transgenic mouse lines expression of NAD(P)H:quinone oxidoreductase (NQO1)—the most efficient cytosolic enzyme that reductively activates aristolochic acid I (AAI). The mouse tissues used were from previous studies [Arlt et al., Chem. Res. Toxicol. 24 (2011) 1710; Stiborova et al., Toxicol. Sci. 125 (2012) 345], in which the role of microsomal cytochrome P450 (CYP) enzymes in AAI metabolism in vivo had been determined. We found that NQO1 levels in liver, kidney and lung of Cyp1a1(−/−), Cyp1a2(−/−) and Cyp1a1/1a2(−/−) knockout mouse lines, as well as in two CYP1A-humanized mouse lines harboring functional human CYP1A1 and CYP1A2 and lacking the mouse Cyp1a1/1a2 orthologs, differed from NQO1 levels in wild-type mice. NQO1 protein and enzymic activity were induced in hepatic and renal cytosolic fractions isolated from AAI-pretreated mice, compared with those in untreated mice. Furthermore, this increase in hepatic NQO1 enzyme activity was associated with bioactivation of AAI and elevated AAI-DNA adduct levels in ex vivo incubations of cytosolic fractions with DNA and AAI. In conclusion, AAI appears to increase its own metabolic activation by inducing NQO1, thereby enhancing its own genotoxic potential. Highlights: ► NAD(P)H:quinone oxidoreductase expression in Cyp1a knockout and humanized CYP1A mice ► Reductive activation of the nephrotoxic and carcinogenic aristolochic acid I (AAI) ► NAD(P)H:quinone oxidoreductase is induced in mice treated with AAI. ► Induced hepatic enzyme activity resulted in elevated AAI-DNA adduct levels.

NAD(P)H:quinone oxidoreductase expression in Cyp1a-knockout and CYP1A-humanized mouse lines and its effect on bioactivation of the carcinogen aristolochic acid I

International Nuclear Information System (INIS)

Levova, Katerina; Moserova, Michaela; Nebert, Daniel W.; Phillips, David H.; Frei, Eva; Schmeiser, Heinz H.; Arlt, Volker M.; Stiborova, Marie

2012-01-01

Aristolochic acid causes a specific nephropathy (AAN), Balkan endemic nephropathy, and urothelial malignancies. Using Western blotting suitable to determine protein expression, we investigated in several transgenic mouse lines expression of NAD(P)H:quinone oxidoreductase (NQO1)—the most efficient cytosolic enzyme that reductively activates aristolochic acid I (AAI). The mouse tissues used were from previous studies [Arlt et al., Chem. Res. Toxicol. 24 (2011) 1710; Stiborova et al., Toxicol. Sci. 125 (2012) 345], in which the role of microsomal cytochrome P450 (CYP) enzymes in AAI metabolism in vivo had been determined. We found that NQO1 levels in liver, kidney and lung of Cyp1a1(−/−), Cyp1a2(−/−) and Cyp1a1/1a2(−/−) knockout mouse lines, as well as in two CYP1A-humanized mouse lines harboring functional human CYP1A1 and CYP1A2 and lacking the mouse Cyp1a1/1a2 orthologs, differed from NQO1 levels in wild-type mice. NQO1 protein and enzymic activity were induced in hepatic and renal cytosolic fractions isolated from AAI-pretreated mice, compared with those in untreated mice. Furthermore, this increase in hepatic NQO1 enzyme activity was associated with bioactivation of AAI and elevated AAI-DNA adduct levels in ex vivo incubations of cytosolic fractions with DNA and AAI. In conclusion, AAI appears to increase its own metabolic activation by inducing NQO1, thereby enhancing its own genotoxic potential. Highlights: ► NAD(P)H:quinone oxidoreductase expression in Cyp1a knockout and humanized CYP1A mice ► Reductive activation of the nephrotoxic and carcinogenic aristolochic acid I (AAI) ► NAD(P)H:quinone oxidoreductase is induced in mice treated with AAI. ► Induced hepatic enzyme activity resulted in elevated AAI-DNA adduct levels.

In situ calibration using univariate analyses based on the onboard ChemCam targets: first prediction of Martian rock and soil compositions

International Nuclear Information System (INIS)

Fabre, C.; Cousin, A.; Wiens, R.C.; Ollila, A.; Gasnault, O.; Maurice, S.; Sautter, V.; Forni, O.; Lasue, J.; Tokar, R.; Vaniman, D.; Melikechi, N.

2014-01-01

Curiosity rover landed on August 6th, 2012 in Gale Crater, Mars and it possesses unique analytical capabilities to investigate the chemistry and mineralogy of the Martian soil. In particular, the LIBS technique is being used for the first time on another planet with the ChemCam instrument, and more than 75,000 spectra have been returned in the first year on Mars. Curiosity carries body-mounted calibration targets specially designed for the ChemCam instrument, some of which are homgeneous glasses and others that are fine-grained glass-ceramics. We present direct calibrations, using these onboard standards to infer elements and element ratios by ratioing relative peak areas. As the laser spot size is around 300 μm, the LIBS technique provides measurements of the silicate glass compositions representing homogeneous material and measurements of the ceramic targets that are comparable to fine-grained rock or soil. The laser energy and the auto-focus are controlled for all sequences used for calibration. The univariate calibration curves present relatively to very good correlation coefficients with low RSDs for major and ratio calibrations. Trace element calibration curves (Li, Sr, and Mn), down to several ppm, can be used as a rapid tool to draw attention to remarkable rocks and soils along the traverse. First comparisons to alpha-particle X-ray spectroscopy (APXS) data, on selected targets, show good agreement for most elements and for Mg# and Al/Si estimates. SiO 2 estimates using univariate cannot be yet used. Na 2 O and K 2 O estimates are relevant for high alkali contents, but probably under estimated due to the CCCT initial compositions. Very good results for CaO and Al 2 O 3 estimates and satisfactory results for FeO are obtained. - Highlights: • In situ LIBS univariate calibrations are done using the Curiosity onboard standards. • Major and minor element contents can be rapidly obtained. • Trace element contents can be used as a rapid tool along the

Signatures of a quantum dynamical phase transition in a three-spin system in presence of a spin environment

International Nuclear Information System (INIS)

Alvarez, Gonzalo A.; Levstein, Patricia R.; Pastawski, Horacio M.

2007-01-01

We have observed an environmentally induced quantum dynamical phase transition in the dynamics of a two-spin experimental swapping gate [G.A. Alvarez, E.P. Danieli, P.R. Levstein, H.M. Pastawski, J. Chem. Phys. 124 (2006) 194507]. There, the exchange of the coupled states vertical bar ↑,↓> and vertical bar ↓,↑> gives an oscillation with a Rabi frequency b/ℎ (the spin-spin coupling). The interaction, ℎ/τ SE with a spin-bath degrades the oscillation with a characteristic decoherence time. We showed that the swapping regime is restricted only to bτ SE > or approx. ℎ. However, beyond a critical interaction with the environment the swapping freezes and the system enters to a Quantum Zeno dynamical phase where relaxation decreases as coupling with the environment increases. Here, we solve the quantum dynamics of a two-spin system coupled to a spin-bath within a Liouville-von Neumann quantum master equation and we compare the results with our previous work within the Keldysh formalism. Then, we extend the model to a three interacting spin system where only one is coupled to the environment. Beyond a critical interaction the two spins not coupled to the environment oscillate with the bare Rabi frequency and relax more slowly. This effect is more pronounced when the anisotropy of the system-environment (SE) interaction goes from a purely XY to an Ising interaction form

Assessing regional scale predictions of aerosols, marine stratocumulus, and their interactions during VOCALS-REx using WRF-Chem

Directory of Open Access Journals (Sweden)

Q. Yang

2011-12-01

Full Text Available This study assesses the ability of the recent chemistry version (v3.3 of the Weather Research and Forecasting (WRF-Chem model to simulate boundary layer structure, aerosols, stratocumulus clouds, and energy fluxes over the Southeast Pacific Ocean. Measurements from the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx and satellite retrievals (i.e., products from the MODerate resolution Imaging Spectroradiometer (MODIS, Clouds and Earth's Radiant Energy System (CERES, and GOES-10 are used for this assessment. The Morrison double-moment microphysics scheme is newly coupled with interactive aerosols in the model. The 31-day (15 October–16 November 2008 WRF-Chem simulation with aerosol-cloud interactions (AERO hereafter is also compared to a simulation (MET hereafter with fixed cloud droplet number concentrations in the microphysics scheme and simplified cloud and aerosol treatments in the radiation scheme. The well-simulated aerosol quantities (aerosol number, mass composition and optical properties, and the inclusion of full aerosol-cloud couplings lead to significant improvements in many features of the simulated stratocumulus clouds: cloud optical properties and microphysical properties such as cloud top effective radius, cloud water path, and cloud optical thickness. In addition to accounting for the aerosol direct and semi-direct effects, these improvements feed back to the simulation of boundary-layer characteristics and energy budgets. Particularly, inclusion of interactive aerosols in AERO strengthens the temperature and humidity gradients within the capping inversion layer and lowers the marine boundary layer (MBL depth by 130 m from that of the MET simulation. These differences are associated with weaker entrainment and stronger mean subsidence at the top of the MBL in AERO. Mean top-of-atmosphere outgoing shortwave fluxes, surface latent heat, and surface downwelling longwave fluxes are in better agreement with

Estimation of vanadium water quality benchmarks for the protection of aquatic life with relevance to the Athabasca Oil Sands region using species sensitivity distributions.

Science.gov (United States)

Schiffer, Stephanie; Liber, Karsten

2017-11-01

Elevated vanadium (V) concentrations in oil sands coke, which is produced and stored on site of some major Athabasca Oil Sands companies, could pose a risk to aquatic ecosystems in northern Alberta, Canada, depending on its future storage and utilization. In the present study, V toxicity was determined in reconstituted Athabasca River water to various freshwater organisms, including 2 midge species (Chironomus dilutus and Chironomus riparius; 4-d and 30-d to 40-d exposures) and 2 freshwater fish species (Oncorhynchus mykiss and Pimephales promelas; 4-d and 28-d exposures) to facilitate estimation of water quality benchmarks. The acute toxicity of V was 52.0 and 63.2 mg/L for C. dilutus and C. riparius, respectively, and 4.0 and 14.8 mg V/L for P. promelas and O. mykiss, respectively. Vanadium exposure significantly impaired adult emergence of C. dilutus and C. riparius at concentrations ≥16.7 (31.6% reduction) and 8.3 (18.0% reduction) mg/L, respectively. Chronic toxicity in fish presented as lethality, with chronic 28-d LC50s of 0.5 and 4.3 mg/L for P. promelas and O. mykiss, respectively. These data were combined with data from the peer-reviewed literature, and separate acute and chronic species sensitivity distributions (SSDs) were constructed. The acute and chronic hazardous concentrations endangering only 5% of species (HC5) were estimated as 0.64 and 0.05 mg V/L, respectively. These new data for V toxicity to aquatic organisms ensure that there are now adequate data available for regulatory agencies to develop appropriate water quality guidelines for use in the Athabasca Oil Sands region and elsewhere. Until then, the HC5 values presented in the present study could serve as interim benchmarks for the protection of aquatic life from exposure to hazardous levels of V in local aquatic environments. Environ Toxicol Chem 2017;36:3034-3044. © 2017 SETAC. © 2017 SETAC.

The ecotoxicity of zinc and zinc-containing substances in soil with consideration of metal-moiety approaches and organometal complexes.

Science.gov (United States)

Ritchie, Ellyn; Boyd, Patrick; Lawson-Halasz, Annamaria; Hawari, Jalal; Saucier, Stacey; Scroggins, Richard; Princz, Juliska

2017-12-01

Within Canada, screening-level assessments for chemical substances are required to determine whether the substances pose a risk to human health and/or the environment, and as appropriate, risk management strategies. In response to the volume of metal and metal-containing substances, process efficiencies were introduced using a metal-moiety approach, whereby substances that contain a common metal moiety are assessed simultaneously as a group, with the moiety of concern consisting of the metal ion. However, for certain subgroups, such as organometals or organic metal salts, the organic moiety or parent substance may be of concern, rather than simply the metal ion. To further investigate the need for such additional consideration, certain substances were evaluated: zinc (Zn)-containing inorganic (Zn chloride [ZnCl2] and Zn oxide) and organic (organometal: Zn diethyldithiocarbamate [Zn(DDC) 2 ] and organic metal salts (Zn stearate [ZnSt] and 4-chloro-2-nitrobenzenediazonium tetrachlorozincate [BCNZ]). The toxicity of the substances were assessed using plant (Trifolium pratense and Elymus lanceolatus) and soil invertebrate (Folsomia candida and Eisenia andrei) tests in a sandy soil. Effect measures were determined based on total metal and total parent analyses (for organic substances). In general, the inorganic Zn substances were less toxic than the organometals and organic metal salts, with 50% effective concentrations ranging from 11 to >5194 mg Zn kg -1 dry soil. The data demonstrate the necessity for alternate approaches in the assessment of organo-metal complexes, with the organic moieties or parent substances warranting consideration rather than the metal ion alone. In this instance, the organometals and organic metal salts were significantly more toxic than other test substances despite their low total Zn content. Environ Toxicol Chem 2017;36:3324-3332. © 2017 Crown in the Right of Canada. Published by Wiley Periodicals Inc. on behalf of SETAC. © 2017 Crown

Nanoparticle silver coexposure reduces the accumulation of weathered persistent pesticides by earthworms.

Science.gov (United States)

Mukherjee, Arnab; Hawthorne, Joseph; White, Jason C; Kelsey, Jason W

2017-07-01

Although the use of engineered nanomaterials continues to increase, how these materials interact with coexisting contaminants in the environment is largely unknown. The effect of silver (Ag) in bulk, ionic, and nanoparticle (NP; bare and polyvinyl pyrrolidone-coated) forms at 3 concentrations (0 mg/kg, 500 mg/kg, 1000 mg/kg, 2000 mg/kg; ion at 69 mg/kg, 138 mg/kg, 276 mg/kg) on the accumulation of field-weathered chlordane and dichlorodiphenyldichloroethylene + metabolites (DDX) by Eisenia fetida (earthworm) was investigated. Earthworm biomass and survival were unaffected by treatment. At the 500 mg/kg and 1000 mg/kg exposure levels, NP-exposed earthworms contained significantly greater Ag (194-245%) than did the bulk exposed organisms; NP size or coating had no impact on element content. Generally, exposure to Ag of any type or at any concentration significantly reduced pesticide accumulation, although reductions for DDX (35.1%; 8.9-47.0%) were more modest than those for chlordane (79.0%; 17.4-92.9%). For DDX, the reduction in pesticide accumulation was not significantly affected by Ag type or concentration. For chlordane, the 3 NP exposures suppressed chlordane accumulation significantly more than did bulk exposure; earthworms exposed to bulk Ag contained 1170 ng/g chlordane, but levels in the NP-exposed earthworms were 279 ng/g. At the 500 mg/kg exposure, the smallest coated NPs exerted the greatest suppression in chlordane accumulation; at the 2 higher concentrations, chlordane uptake was unaffected by NP size or coating. The findings show that in exposed earthworms Ag particle size does significantly impact accumulation of the element itself, as well as that of coexisting weathered pesticides. The implications of these findings with regard to NP exposure and risk are unknown but are the topic of current investigation. Environ Toxicol Chem 2017;36:1864-1871. © 2016 SETAC. © 2016 SETAC.

Recalibration of the Mars Science Laboratory ChemCam instrument with an expanded geochemical database

Science.gov (United States)

Clegg, Samuel M.; Wiens, Roger C.; Anderson, Ryan; Forni, Olivier; Frydenvang, Jens; Lasue, Jeremie; Cousin, Agnes; Payre, Valerie; Boucher, Tommy; Dyar, M. Darby; McLennan, Scott M.; Morris, Richard V.; Graff, Trevor G.; Mertzman, Stanley A; Ehlmann, Bethany L.; Belgacem, Ines; Newsom, Horton E.; Clark, Ben C.; Melikechi, Noureddine; Mezzacappa, Alissa; McInroy, Rhonda E.; Martinez, Ronald; Gasda, Patrick J.; Gasnault, Olivier; Maurice, Sylvestre

2017-01-01

The ChemCam Laser-Induced Breakdown Spectroscopy (LIBS) instrument onboard the Mars Science Laboratory (MSL) rover Curiosity has obtained > 300,000 spectra of rock and soil analysis targets since landing at Gale Crater in 2012, and the spectra represent perhaps the largest publicly-available LIBS datasets. The compositions of the major elements, reported as oxides (SiO2, TiO2, Al2O3, FeOT, MgO, CaO, Na2O, K2O), have been re-calibrated using a laboratory LIBS instrument, Mars-like atmospheric conditions, and a much larger set of standards (408) that span a wider compositional range than previously employed. The new calibration uses a combination of partial least squares (PLS1) and Independent Component Analysis (ICA) algorithms, together with a calibration transfer matrix to minimize differences between the conditions under which the standards were analyzed in the laboratory and the conditions on Mars. While the previous model provided good results in the compositional range near the average Mars surface composition, the new model fits the extreme compositions far better. Examples are given for plagioclase feldspars, where silicon was significantly over-estimated by the previous model, and for calcium-sulfate veins, where silicon compositions near zero were inaccurate. The uncertainties of major element abundances are described as a function of the abundances, and are overall significantly lower than the previous model, enabling important new geochemical interpretations of the data.

Chem-Prep PZT 95/5 for Neutron Generator Applications: Particle Size Distribution Comparison of Development and Production-Scale Powders

International Nuclear Information System (INIS)

SIPOLA, DIANA L.; VOIGT, JAMES A.; LOCKWOOD, STEVEN J.; RODMAN-GONZALES, EMILY D.

2002-01-01

The Materials Chemistry Department 1846 has developed a lab-scale chem-prep process for the synthesis of PNZT 95/5, a ferroelectric material that is used in neutron generator power supplies. This process (Sandia Process, or SP) has been successfully transferred to and scaled by Department 14192 (Ceramics and Glass Department), (Transferred Sandia Process, or TSP), to meet the future supply needs of Sandia for its neutron generator production responsibilities. In going from the development-size SP batch (1.6 kg/batch) to the production-scale TSP powder batch size (10 kg/batch), it was important that it be determined if the scaling process caused any ''performance-critical'' changes in the PNZT 95/5 being produced. One area where a difference was found was in the particle size distributions of the calcined PNZT powders. Documented in this SAND report are the results of an experimental study to determine the origin of the differences in the particle size distribution of the SP and TSP powders

Effects of 4-ter-Octylphenol on Xenopus tropicalis in a Long Term Exposure

Science.gov (United States)

2011-03-17

Aquat Toxicol 80, 1-22. Oehlmann, J., Fioroni, P., Stroben, E., and Markert, B., 1996. Tributyltin ( TBT ) effects on Ocinebrina aciculata (Gastropoda...Female gastropods exposed to the androgenic EDC, tributyltin , developed an imposex condition that prevented proper reproduction in these animals...induction and gonadal development. Aquat Toxicol 88, 39-47. Bailey, S.K. and Davies, I.M., 1988. Tributyltin contamination in the Firth of Forth

Spatio-temporal variability of CO and O3 in Hyderabad (17°N, 78°E, central India, based on MOZAIC and TES observations and WRF-Chem and MOZART-4 models

Directory of Open Access Journals (Sweden)

Varun Sheel

2016-05-01

Full Text Available This article is based on the study of the seasonal and interannual variability of carbon monoxide (CO and ozone (O3 at different altitudes of the troposphere over Hyderabad, India, during 2006–2010 using Measurement of OZone and water vapour by Airbus In-Service Aircraft (MOZAIC and observation from Tropospheric Emission Spectrometer (TES aboard NASA's Aura satellite. The MOZAIC observations show maximum seasonal variability in both CO and O3 during winter and pre-monsoon season, with CO in the range (100–200±13 ppbv and O3 in the range (50–70±9 ppbv. The time-series of MOZAIC data shows a significant increase of 4.2±1.3 % in the surface CO and 6.7±1.3 % in the surface O3 during 2006–2010 in Hyderabad. From MOZAIC observations, we identify CO and O3 profiles that are anomalous with respect to the monthly mean and compare those with Weather Research Forecast model coupled with Chemistry (WRF-Chem and Model for OZone and Related Tracers, version 4 profiles for the same day. The anomalous profiles of WRF-Chem are simulated using three convection schemes. The goodness of comparison depends on the convection scheme and the altitude region of the troposphere.

Trace element geochemistry (Li, Ba, Sr, and Rb) using Curiosity's ChemCam: early results for Gale crater from Bradbury Landing Site to Rocknest

Science.gov (United States)

Ollila, Ann M.; Newsom, Horton E.; Clark, Benton; Wiens, Roger C.; Cousin, Agnes; Blank, Jen G.; Mangold, Nicolas; Sautter, Violaine; Maurice, Sylvestre; Clegg, Samuel M.; Gasnault, Olivier; Forni, Olivier; Tokar, Robert; Lewin, Eric; Dyar, M. Darby; Lasue, Jeremie; Anderson, Ryan; McLennan, Scott M.; Bridges, John; Vaniman, Dave; Lanza, Nina; Fabre, Cecile; Melikechi, Noureddine; Perett, Glynis M.; Campbell, John L.; King, Penelope L.; Barraclough, Bruce; Delapp, Dorothea; Johnstone, Stephen; Meslin, Pierre-Yves; Rosen-Gooding, Anya; Williams, Josh

2014-01-01

The ChemCam instrument package on the Mars rover, Curiosity, provides new capabilities to probe the abundances of certain trace elements in the rocks and soils on Mars using the laser-induced breakdown spectroscopy technique. We focus on detecting and quantifying Li, Ba, Rb, and Sr in targets analyzed during the first 100 sols, from Bradbury Landing Site to Rocknest. Univariate peak area models and multivariate partial least squares models are presented. Li, detected for the first time directly on Mars, is generally low (100 ppm and >1000 ppm, respectively. These analysis locations tend to have high Si and alkali abundances, consistent with a feldspar composition. Together, these trace element observations provide possible evidence of magma differentiation and aqueous alteration.

Oxidative stress induced by glyphosate-based herbicide on freshwater turtles.

Science.gov (United States)

Héritier, Laurent; Duval, David; Galinier, Richard; Meistertzheim, Anne-Leila; Verneau, Olivier

2017-12-01

Freshwater ecosystems face very strong anthropogenic pressures, among which overexploitation, habitat degradation, flow modification, species invasion, and water pollution lead to growing threats on biodiversity. Urbanization through wastewater treatment, industry through the release of inorganic and organic chemicals, and agriculture through the use of pesticides and herbicides are the main factors involved in water pollution. In France, more precisely in the Pyrénées-Orientales department, the poor quality of the watercourses is attributable overall to the use of glyphosate-based herbicides in agricultural activities. Because these chemicals can impact individuals, populations, and biodiversity, we investigated, under experimental conditions, the physiological response of animals facing abiotic contaminants. We selected as a model, juveniles of the freshwater turtle Trachemys scripta elegans. We measured the gene expression and activity of the catalase and superoxide dismutase enzymes as well as the levels of lipid peroxidation, which are all oxidative stress biomarkers, in turtles challenged with high concentrations of glyphosate-based herbicides, on the one hand, and with degraded waters collected from a local watercourse, on the other. We also measured the acetylcholinesterase activity across the same animals. We showed through variations in gene expression and enzyme activity that a glyphosate commercial formulation induced a stress in turtles. A similar outcome was obtained when turtles faced degraded waters. The results indicated that the poor quality of regional waters could be a real threat for animal health. Because turtles are globally less sensitive to contaminants than amphibians, which are lacking in the degraded waters of the Pyrénées-Orientales department, they could constitute an excellent model to follow the evolution of water quality through the study of oxidative stress biomarkers. Environ Toxicol Chem 2017;36:3343-3350. © 2017 SETAC. �

Exposure to a PBDE/OH-BDE mixture alters juvenile zebrafish (Danio rerio) development.

Science.gov (United States)

Macaulay, Laura J; Chernick, Melissa; Chen, Albert; Hinton, David E; Bailey, Jordan M; Kullman, Seth W; Levin, Edward D; Stapleton, Heather M

2017-01-01

Polybrominated diphenyl ethers (PBDEs) and their metabolites (e.g., hydroxylated BDEs [OH-BDEs]) are contaminants frequently detected together in human tissues and are structurally similar to thyroid hormones. Thyroid hormones partially mediate metamorphic transitions between life stages in zebrafish, making this a critical developmental window that may be vulnerable to chemicals disrupting thyroid signaling. In the present study, zebrafish were exposed to 6-OH-BDE-47 (30 nM; 15 μg/L) alone, or to a low-dose (30 μg/L) or high-dose (600 μg/L) mixture of PentaBDEs, 6-OH-BDE-47 (0.5-6 μg/L), and 2,4,6-tribromophenol (5-100 μg/L) during juvenile development (9-23 d postfertilization) and evaluated for developmental endpoints mediated by thyroid hormone signaling. Fish were sampled at 3 time points and examined for developmental and skeletal morphology, apical thyroid and skeletal gene markers, and modifications in swimming behavior (as adults). Exposure to the high-dose mixture resulted in >85% mortality within 1 wk of exposure, despite being below reported acute toxicity thresholds for individual congeners. The low-dose mixture and 6-OH-BDE-47 groups exhibited reductions in body length and delayed maturation, specifically relating to swim bladder, fin, and pigmentation development. Reduced skeletal ossification was also observed in 6-OH-BDE-47-treated fish. Assessment of thyroid and osteochondral gene regulatory networks demonstrated significantly increased expression of genes that regulate skeletal development and thyroid hormones. Overall, these results indicate that exposures to PBDE/OH-BDE mixtures adversely impact zebrafish maturation during metamorphosis. Environ Toxicol Chem 2017;36:36-48. © 2016 SETAC. © 2016 SETAC.

Effects of bifenthrin exposure on the estrogenic and dopaminergic pathways in zebrafish embryos and juveniles.

Science.gov (United States)

Bertotto, Luísa Becker; Richards, Jaben; Gan, Jay; Volz, David Christopher; Schlenk, Daniel

2018-01-01

Bifenthrin is a pyrethroid insecticide used in urban and agricultural applications. Previous studies have shown that environmentally relevant (ng/L) concentrations of bifenthrin increased plasma concentrations of 17β-estradiol (E2) and altered the expression of dopaminergic pathway components. The dopaminergic neurons can indirectly regulate E2 biosynthesis, suggesting that bifenthrin may disrupt the hypothalamic-pituitary-gonadal (HPG) axis. Because embryos do not have a complete HPG axis, the hypothesis that bifenthrin impairs dopamine regulation was tested in embryonic and 1-mo-old juvenile zebrafish (Danio rerio) with exposure to measured concentrations of 0.34 and 3.1 µg/L bifenthrin for 96 h. Quantitative reverse transcriptase polymerase chain reaction was used to investigate transcripts of tyrosine hydroxylase (TH), dopamine receptor 1 (DR1) and 2A (DR2A), dopamine active transporter (DAT), estrogen receptor α (ERα), ERβ1, ERβ2, luteinizing hormone β (LHβ), follicle-stimulating hormone β (FSHβ), vitellogenin (VTG), cytochrome P450 cyp19a1a, and cyp19a1b. Levels of E2 were measured by enzyme-linked immunosorbent assay (ELISA). Dopamine and its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) concentrations were measured by liquid chromatrography-tandem mass spectrometry (LC-MS/MS). Significant decreases in TH and DR1 transcripts and HVA levels, as well as ratios of HVA/dopamine and HVA+DOPAC/dopamine, in zebrafish embryos were observed after bifenthrin treatment. In juveniles, a significant increase in the expression of ERβ1 and the DOPAC to dopamine ratio was noted. These results show a possible antiestrogenic effect of bifenthrin in embryos, and estrogenicity in juveniles, indicating life-stage-dependent toxicity in developing fish. Environ Toxicol Chem 2018;37:236-246. © 2017 SETAC. © 2017 SETAC.

Effects of soot by-product from the synthesis of engineered metallofullerene nanomaterials on terrestrial invertebrates.

Science.gov (United States)

Johnson, David R; Boyd, Robert E; Bednar, Anthony J; Weiss, Charles A; Hull, Matt S; Coleman, Jessica G; Kennedy, Alan J; Banks, Cynthia J; Steevens, Jeffery A

2018-02-23

The synthesis of carbon-based nanomaterials is often inefficient, generating large amounts of soot with metals as waste by-product. Currently, there are no specific regulations for disposal of engineered nanomaterials or the waste by-products resulting from their synthesis, so it is presumed that by-products are disposed of in the same way as the parent (bulk) materials. We studied the terrestrial toxicity of soot from gadolinium metallofullerene nanomanufacturing on earthworms (Eisenia fetida) and isopods (Porcellio scaber). The metallofullerene soot consisted of carbon particle agglomerates in the nanometer and submicrometer ranges (1-100 and 101-999 nm, respectively), with metals used during nanomanufacturing detectable on the particles. Despite high metal concentrations (>100 000 mg/kg) in the soot, only a relatively small amount of metals leached out of a spiked field soil, suggesting only moderate mobility. Seven- and 14-d exposures in field soil demonstrated that the soot was only toxic to earthworms at high concentrations (>10 000 mg/kg); however, earthworms avoided spiked soils at lower concentrations (as low as 500 mg/kg) and at lower soil pH. The presence of soot in food and soil did not cause isopod avoidance. These data demonstrate that metallofullerene soot from nanomanufacturing may only be toxic to earthworms at high concentrations representative of improper disposal or accidental spills. However, our results indicate that terrestrial invertebrates may avoid soils contaminated with soot at sublethal concentrations. Environ Toxicol Chem 2018;9999:1-12. Published 2018 Wiley Periodicals, Inc. on behalf of SETAC. This article is a US government work, and as such, is in the public domain in the United States of America. Published 2018 Wiley Periodicals, Inc. on behalf of SETAC. This article is a US government work, and as such, is in the public domain in the United States of America.

Tissue-specific bioconcentration and biotransformation of cypermethrin and chlorpyrifos in a native fish (Jenynsia multidentata) exposed to these insecticides singly and in mixtures.

Science.gov (United States)

Bonansea, Rocío Inés; Marino, Damián J G; Bertrand, Lidwina; Wunderlin, Daniel A; Amé, María Valeria

2017-07-01

The aim of the present study was to evaluate the accumulation of cypermethrin and chlorpyrifos when the fish Jenynsia multidentata was exposed to these pesticides singly and in technical and commercial mixtures. Adult female fish were exposed over 96 h to 0.04 μg/L of cypermethrin; 0.4 μg/L of chlorpyrifos; 0.04 μg/L of cypermethrin + 0.4 μg/L of chlorpyrifos in a technical mixture; and 0.04 μg/L of cypermethrin + 0.4 μg/L of chlorpyrifos in a mixture of commercial products. Fish exposed to cypermethrin accumulated this compound only in muscle, probably because of the low biotransformation capacity of this organ and the induction of cytochrome P4501A1 (CYP1A1) expression in the liver. The accumulation of chlorpyrifos occurred in fish exposed to the insecticide (intestine > liver > gills) even when these fish had higher gluthatione-S-transferase (GST) activity in gills and P-glycoprotein (P-gp) expression in the liver, compared with the control. Fish exposed to the technical mixture showed cypermethrin accumulation (liver > intestine > gills) with higher levels than those measured in fish after only cypermethrin exposure. Higher expression levels of CYP1A1 in the liver were also observed compared with the Control. Fish exposed to the commercial mixture accumulated both insecticides (cypermethrin: intestine > gills and chlorpyrifos: liver > intestine > gills > muscle). In the organs where accumulation occurred, biotransformation enzymes were inhibited. Consequently, the commercial formulation exposure provoked the highest accumulation of cypermethrin and chlorpyrifos in J. multidentata, possibly associated with the biotransformation system inhibition. Environ Toxicol Chem 2017;36:1764-1774. © 2016 SETAC. © 2016 SETAC.

Is the tier-1 effect assessment for herbicides protective for aquatic algae and vascular plant communities?

Science.gov (United States)

van Wijngaarden, René P A; Arts, Gertie H P

2018-01-01

In the aquatic tier-1 effect assessment for plant protection products with an herbicidal mode of action in Europe, it is usually algae and/or vascular plants that determine the environmental risks. This tier includes tests with at least 2 algae and 1 macrophyte (Lemna). Although such tests are considered to be of a chronic nature (based on the duration of the test in relation to the life cycle of the organism), the measurement endpoints derived from the laboratory tests with plants (including algae) and used in the first-tier effect assessment for herbicides are acute effect concentrations affecting 50% of the test organisms (EC50 values) and not no-observed-effect concentrations (NOECs) or effect concentrations affecting 10% of the test organisms (EC10) values. Other European legislative frameworks (e.g., the Water Framework Directive) use EC10 values. The present study contributes to a validation of the tiered herbicide risk assessment approach by comparing the standard first-tier effect assessment with results of microcosm and mesocosm studies. We evaluated EC50 and EC10 values for standard test algae and macrophytes based on either the growth rate endpoint (E r C50) or the lowest available endpoint for growth rate or biomass/yield (E r /E y C50). These values were compared with the regulatory acceptable concentrations for the threshold option as derived from microcosm and mesocosm studies. For these studies, protection is maintained if growth rate is taken as the regulatory endpoint instead of the lowest value of either growth rate or biomass/yield in conjunction with the standard assessment factor of 10. Based on a limited data set of 14 herbicides, we did not identify a need to change the current practice. Environ Toxicol Chem 2018;37:175-183. © 2017 SETAC. © 2017 SETAC.

Riparian spiders as sentinels of polychlorinated biphenyl contamination across heterogeneous aquatic ecosystems

Science.gov (United States)

Kraus, Johanna M.; Gibson, Polly P.; Walters, David M.; Mills, Marc A.

2017-01-01

Riparian spiders are being used increasingly to track spatial patterns of contaminants in and fluxing from aquatic ecosystems.However, our understanding of the circumstances under which spiders are effective sentinels of aquatic pollution is limited. The present study tests the hypothesis that riparian spiders may be effectively used to track spatial patterns of sediment pollution by polychlorinated biphenyls (PCBs) in aquatic ecosystems with high habitat heterogeneity. The spatial pattern of ΣPCB concentrations in 2 common families of riparian spiders sampled in 2011 to 2013 generally tracked spatial variation in sediment ΣPCBs across all sites within the Manistique River Great Lakes Area of Concern (AOC), a rivermouth ecosystem located on the south shore of the Upper Peninsula, Manistique (MI,USA) that includes harbor, river, backwater, and lake habitats. Sediment ΣPCB concentrations normalized for total organic carbon explained 41% of the variation in lipid-normalized spider ΣPCB concentrations across 11 sites. Furthermore, 2 common riparian spider taxa (Araneidae and Tetragnathidae) were highly correlated (r2> 0.78) and had similar mean ΣPCB concentrations when averaged acrossall years. The results indicate that riparian spiders may be useful sentinels of relative PCB availability to aquatic and riparian food webs in heterogeneous aquatic ecosystems like rivermouths where habitat and contaminant variability may make the use of aquatic taxa lesseffective. Furthermore, the present approach appears robust to heterogeneity in shoreline development and riparian vegetation that support different families of large web-building spiders. Environ Toxicol Chem 2016;9999:1–9. Published 2016 Wiley Periodicals, Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Toxicological perspective on the osmoregulation and ionoregulation physiology of major ions by freshwater animals: Teleost fish, crustacea, aquatic insects, and Mollusca.

Science.gov (United States)

Griffith, Michael B

2017-03-01

Anthropogenic sources increase freshwater salinity and produce differences in constituent ions compared with natural waters. Moreover, ions differ in physiological roles and concentrations in intracellular and extracellular fluids. Four freshwater taxa groups are compared, to investigate similarities and differences in ion transport processes and what ion transport mechanisms suggest about the toxicity of these or other ions in freshwater. Although differences exist, many ion transporters are functionally similar and may belong to evolutionarily conserved protein families. For example, the Na + /H + -exchanger in teleost fish differs from the H + /2Na + (or Ca 2+ )-exchanger in crustaceans. In osmoregulation, Na + and Cl - predominate. Stenohaline freshwater animals hyperregulate until they are no longer able to maintain hypertonic extracellular Na + and Cl - concentrations with increasing salinity and become isotonic. Toxic effects of K + are related to ionoregulation and volume regulation. The ionic balance between intracellular and extracellular fluids is maintained by Na + /K + -adenosine triphosphatase (ATPase), but details are lacking on apical K + transporters. Elevated H + affects the maintenance of internal Na + by Na + /H + exchange; elevated HCO 3 - inhibits Cl - uptake. The uptake of Mg 2+ occurs by the gills or intestine, but details are lacking on Mg 2+ transporters. In unionid gills, SO 4 2- is actively transported, but most epithelia are generally impermeant to SO 4 2- . Transporters of Ca 2+ maintain homeostasis of dissolved Ca 2+ . More integration of physiology with toxicology is needed to fully understand freshwater ion effects. Environ Toxicol Chem 2017;36:576-600. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the

Later life swimming performance and persistent heart damage following subteratogenic PAH mixture exposure in the Atlantic killifish (Fundulus heteroclitus).

Science.gov (United States)

Brown, Daniel R; Thompson, Jasmine; Chernick, Melissa; Hinton, David E; Di Giulio, Richard T

2017-12-01

diminished swimming performance of King's Creek fish. Environ Toxicol Chem 2017;36:3246-3253. © 2017 SETAC. © 2017 SETAC.

Toxicity reference values for methylmercury effects on avian reproduction: Critical review and analysis.

Science.gov (United States)

Fuchsman, Phyllis C; Brown, Lauren E; Henning, Miranda H; Bock, Michael J; Magar, Victor S

2017-02-01

Effects of mercury (Hg) on birds have been studied extensively and with increasing frequency in recent years. The authors conducted a comprehensive review of methylmercury (MeHg) effects on bird reproduction, evaluating laboratory and field studies in which observed effects could be attributed primarily to Hg. The review focuses on exposures via diet and maternal transfer in which observed effects (or lack thereof) were reported relative to Hg concentrations in diet, eggs, or adult blood. Applicable data were identified for 23 species. From this data set, the authors identified ranges of toxicity reference values suitable for risk-assessment applications. Typical ranges of Hg effect thresholds are approximately 0.2 mg/kg to >1.4 mg/kg in diet, 0.05 mg/kg/d to 0.5 mg/kg/d on a dose basis, 0.6 mg/kg to 2.7 mg/kg in eggs, and 2.1 mg/kg to >6.7 mg/kg in parental blood (all concentrations on a wet wt basis). For Hg in avian blood, the review represents the first broad compilation of relevant toxicity data. For dietary exposures, the current data support TRVs that are greater than older, commonly used TRVs. The older diet-based TRVs incorporate conservative assumptions and uncertainty factors that are no longer justified, although they generally were appropriate when originally derived, because of past data limitations. The egg-based TRVs identified from the review are more similar to other previously derived TRVs but have been updated to incorporate new information from recent studies. While important research needs remain, a key recommendation is that species not yet tested for MeHg toxicity should be evaluated using toxicity data from tested species with similar body weights. Environ Toxicol Chem 2017;36:294-319. © 2016 SETAC. © 2016 SETAC.

Cumulative toxicity of neonicotinoid insecticide mixtures to Chironomus dilutus under acute exposure scenarios.

Science.gov (United States)

Maloney, Erin M; Morrissey, Christy A; Headley, John V; Peru, Kerry M; Liber, Karsten

2017-11-01

exposures, and the consideration of mixture effects when setting water quality guidelines for this class of pesticides. Environ Toxicol Chem 2017;36:3091-3101. © 2017 SETAC. © 2017 SETAC.

Multimedia screening of contaminants of emerging concern (CECS) in coastal urban watersheds in southern California (USA).

Science.gov (United States)

Maruya, Keith A; Dodder, Nathan G; Sengupta, Ashmita; Smith, Deborah J; Lyons, J Michael; Heil, Ann T; Drewes, Jörg E

2016-08-01

To examine the occurrence and fate of contaminants of emerging concern (CECs) and inform future monitoring of CECs in coastal urban waterways, water, sediment, and fish tissue samples were collected and analyzed for a broad suite of pharmaceuticals and personal care products (PPCPs), commercial and/or household chemicals, current use pesticides, and hormones in an effluent-dominated river and multiple embayments in southern California (USA). In the Santa Clara River, which receives treated wastewater from several facilities, aqueous phase CECs were detectable at stations nearest discharges from municipal wastewater treatment plants but were attenuated downstream. Sucralose and the chlorinated phosphate flame retardants tris(1-chloro-2-propyl) phosphate (TCPP), tris(1,3-dichloro-2-propyl) phosphate (TDCPP), and tris(2-chloroethyl) phosphate (TCEP) were most abundant in water, with maximum concentrations of 35 μg/L, 3.3 μg/L, 1.4 μg/L, and 0.81 μg/L, respectively. Triclocarban, an antimicrobial agent in use for decades, was more prevalent in water than triclosan or nonylphenol. Maximum concentrations of bifenthrin, permethrin, polybrominated diphenyl ethers (PBDEs), and degradates of fipronil exceeded CEC-specific monitoring trigger levels recently established for freshwater and estuarine sediments by factors of 10 to 1000, respectively. Maximum fish tissue concentrations of PBDEs varied widely (370 ng/g and 7.0 ng/g for the Santa Clara River and coastal embayments, respectively), with most species exhibiting concentrations at the lower end of this range. These results suggest that continued monitoring of pyrethroids, PBDEs, and degradates of fipronil in sediment is warranted in these systems. In contrast, aqueous pharmaceutical concentrations in the Santa Clara River were not close to exceeding current monitoring trigger levels, suggesting a lower priority for targeted monitoring in this medium. Environ Toxicol Chem 2016;35:1986-1994. © 2016 SETAC

Multiple linear regression models for predicting chronic aluminum toxicity to freshwater aquatic organisms and developing water quality guidelines.

Science.gov (United States)

DeForest, David K; Brix, Kevin V; Tear, Lucinda M; Adams, William J

2018-01-01

The bioavailability of aluminum (Al) to freshwater aquatic organisms varies as a function of several water chemistry parameters, including pH, dissolved organic carbon (DOC), and water hardness. We evaluated the ability of multiple linear regression (MLR) models to predict chronic Al toxicity to a green alga (Pseudokirchneriella subcapitata), a cladoceran (Ceriodaphnia dubia), and a fish (Pimephales promelas) as a function of varying DOC, pH, and hardness conditions. The MLR models predicted toxicity values that were within a factor of 2 of observed values in 100% of the cases for P. subcapitata (10 and 20% effective concentrations [EC10s and EC20s]), 91% of the cases for C. dubia (EC10s and EC20s), and 95% (EC10s) and 91% (EC20s) of the cases for P. promelas. The MLR models were then applied to all species with Al toxicity data to derive species and genus sensitivity distributions that could be adjusted as a function of varying DOC, pH, and hardness conditions (the P. subcapitata model was applied to algae and macrophytes, the C. dubia model was applied to invertebrates, and the P. promelas model was applied to fish). Hazardous concentrations to 5% of the species or genera were then derived in 2 ways: 1) fitting a log-normal distribution to species-mean EC10s for all species (following the European Union methodology), and 2) fitting a triangular distribution to genus-mean EC20s for animals only (following the US Environmental Protection Agency methodology). Overall, MLR-based models provide a viable approach for deriving Al water quality guidelines that vary as a function of DOC, pH, and hardness conditions and are a significant improvement over bioavailability corrections based on single parameters. Environ Toxicol Chem 2018;37:80-90. © 2017 SETAC. © 2017 SETAC.

Tissue explant coculture model of the hypothalamic-pituitary-gonadal-liver axis of the fathead minnow (Pimephales promelas) as a predictive tool for endocrine disruption.

Science.gov (United States)

Johnston, Theresa K; Perkins, Edward; Ferguson, Duncan C; Cropek, Donald M

2016-10-01

Endocrine-disrupting compounds (EDCs) can impact the reproductive system by interfering with the hypothalamic-pituitary-gonadal (HPG) axis. Although in vitro testing methods have been developed to screen chemicals for endocrine disruption, extrapolation of in vitro responses to in vivo action shows inconsistent accuracy. The authors describe a tissue coculture of the fathead minnow (Pimephales promelas) HPG axis and liver (HPG-L) as a tissue explant model that mimics in vivo results. Brain (hypothalamus), pituitary, gonad, and liver tissue explants from adult fish were examined for function both individually and in coculture to determine combinations and conditions that could replicate in vivo behavior. Only cocultures had the ability to respond to an EDC, trenbolone, similarly to in vivo studies, based on estradiol, testosterone, and vitellogenin production trends, where lower exposure doses suppressed hormone production but higher doses increased production, resulting in distinctive U-shaped curves. These data suggest that a coculture system with all components of the HPG-L axis can be used as a link between in vitro and in vivo studies to predict endocrine system disruption in whole organisms. This tissue-based HPG-L system acts as a flexible deconstructed version of the in vivo system for better control and examination of the minute changes in system operation and response on EDC exposure with options to isolate, interrogate, and recombine desired components. Environ Toxicol Chem 2016;35:2530-2541. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America.

Current-use pesticides in seawater and their bioaccumulation in polar bear-ringed seal food chains of the Canadian Arctic.

Science.gov (United States)

Morris, Adam D; Muir, Derek C G; Solomon, Keith R; Letcher, Robert J; McKinney, Melissa A; Fisk, Aaron T; McMeans, Bailey C; Tomy, Gregg T; Teixeira, Camilla; Wang, Xiaowa; Duric, Mark

2016-07-01

The distribution of current-use pesticides (CUPs) in seawater and their trophodynamics were investigated in 3 Canadian Arctic marine food chains. The greatest ranges of dissolved-phase concentrations in seawater for each CUP were endosulfan sulfate (less than method detection limit (MDL) to 19 pg L(-1) ) > dacthal (0.76-15 pg L(-1) ) > chlorpyrifos (less than MDL to 8.1 pg L(-1) ) > pentachloronitrobenzene (less than MDL to 2.6 pg L(-1) ) > α-endosulfan (0.20-2.3 pg L(-1) ). Bioaccumulation factors (BAFs, water-respiring organisms) were greatest in plankton, including chlorothalonil (log BAF = 7.4 ± 7.1 L kg(-1) , mean ± standard error), chlorpyrifos (log BAF = 6.9 ± 6.7 L kg(-1) ), and α-endosulfan (log BAF = 6.5 ± 6.0 L kg(-1) ). The largest biomagnification factors (BMFs) were found for dacthal in the capelin:plankton trophic relationship (BMF = 13 ± 5.0) at Cumberland Sound (Nunvavut), and for β-endosulfan (BMF = 16 ± 4.9) and α-endosulfan (BMF = 9.3 ± 2.8) in the polar bear-ringed seal relationship at Barrow and Rae Strait (NU), respectively. Concentrations of endosulfan sulfate exhibited trophic magnification (increasing concentrations with increasing trophic level) in the poikilothermic portion of the food web (trophic magnification factor = 1.4), but all of the CUPs underwent trophic dilution in the marine mammal food web, despite some trophic level-specific biomagnification. Together, these observations are most likely indicative of metabolism of these CUPs in mammals. Environ Toxicol Chem 2016;35:1695-1707. © 2016 SETAC. © 2016 SETAC.

A field test of the effect of spiked ivermectin concentrations on the biodiversity of coprophagous dung insects in Switzerland.

Science.gov (United States)

Jochmann, Ralf; Lipkow, Erhard; Blanckenhorn, Wolf U

2016-08-01

Veterinary medical product residues can cause severe damage in the dung ecosystem. Depending on the manner of application and the time after treatment, the excreted concentration of a given pharmaceutical varies. The popular anthelmintic drug ivermectin can be applied to livestock in several different ways and is fecally excreted over a period of days to months after application. In a field experiment replicated in summer and autumn, the authors mixed 6 ivermectin concentrations plus a null control into fresh cow dung to assess the reaction of the dung insect community. Taxon richness of the insect dung fauna emerging from the dung, but not Hill diversity ((1) D) or the total number of individuals (abundance), decreased as ivermectin concentration increased. Corresponding declines in the number of emerging insects were found for most larger brachyceran flies and hymenopteran parasitoids, but not for most smaller nematoceran flies or beetles (except Hydrophilidae). Parallel pitfall traps recovered all major dung organism groups that emerged from the experimental dung, although at times in vastly different numbers. Ivermectin generally did not change the attractiveness of dung: differences in emergence therefore reflect differences in survival of coprophagous offspring of colonizing insects. Because sample size was limited to 6 replicates, the authors generally recommend more than 10 (seasonal) replicates and also testing higher concentrations than used in the present study as positive controls in future studies. Results accord with parallel experiments in which the substance was applied and passed through the cow's digestive system. In principle, therefore, the authors' experimental design is suitable for such higher-tier field tests of the response of the entire dung community to pharmaceutical residues, at least for ivermectin. Environ Toxicol Chem 2016;35:1947-1952. © 2015 SETAC. © 2015 SETAC.

Silver nanoparticles in sewage sludge: Bioavailability of sulfidized silver to the terrestrial isopod Porcellio scaber.

Science.gov (United States)

Kampe, Sebastian; Kaegi, Ralf; Schlich, Karsten; Wasmuth, Claus; Hollert, Henner; Schlechtriem, Christian

2018-06-01

Silver nanoparticles (AgNPs) are efficiently converted during the wastewater-treatment process into sparingly soluble Ag sulfides (Ag 2 S). In several countries, sewage sludge is used as a fertilizer in agriculture. The bioavailability of sulfidized Ag to the terrestrial isopod Porcellio scaber was investigated. Sewage sludge containing transformed AgNPs was obtained from a laboratory-scale sewage-treatment plant operated according to Organisation for Economic Co-operation and Development (OECD) guideline 303a. The results of transmission electron microscopy with energy dispersive X-ray of sludge samples suggest that AgNPs were completely transformed to Ag 2 S. Adult isopods were exposed to OECD 207 soil substrate amended with the AgNP spiked sludge for 14 d (uptake phase) followed by an elimination phase in unspiked soil of equal duration. Most of the Ag measured in P. scaber at the end of the uptake phase was found in the hindgut (71%), indicating that only a minor part of the estimated Ag content was actually assimilated by the isopods with 16.3 and 12.7% found in the carcass and hepatopancreas, respectively. As a result of this, the Ag content of the animals dropped following transition to unspiked sludge within 2 d to one-third of the previously measured Ag concentration and remained stable at this level until the end of the elimination period. The present study shows that Ag 2 S in sewage sludge is bioavailable to the terrestrial isopod P. scaber. Environ Toxicol Chem 2018;37:1606-1613. © 2018 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC. © 2018 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

Prospective mixture risk assessment and management prioritizations for river catchments with diverse land uses

Science.gov (United States)

Brown, Colin D.; de Zwart, Dick; Diamond, Jerome; Dyer, Scott D.; Holmes, Christopher M.; Marshall, Stuart; Burton, G. Allen

2018-01-01

Abstract Ecological risk assessment increasingly focuses on risks from chemical mixtures and multiple stressors because ecosystems are commonly exposed to a plethora of contaminants and nonchemical stressors. To simplify the task of assessing potential mixture effects, we explored 3 land use–related chemical emission scenarios. We applied a tiered methodology to judge the implications of the emissions of chemicals from agricultural practices, domestic discharges, and urban runoff in a quantitative model. The results showed land use–dependent mixture exposures, clearly discriminating downstream effects of land uses, with unique chemical “signatures” regarding composition, concentration, and temporal patterns. Associated risks were characterized in relation to the land‐use scenarios. Comparisons to measured environmental concentrations and predicted impacts showed relatively good similarity. The results suggest that the land uses imply exceedances of regulatory protective environmental quality standards, varying over time in relation to rain events and associated flow and dilution variation. Higher‐tier analyses using ecotoxicological effect criteria confirmed that species assemblages may be affected by exposures exceeding no‐effect levels and that mixture exposure could be associated with predicted species loss under certain situations. The model outcomes can inform various types of prioritization to support risk management, including a ranking across land uses as a whole, a ranking on characteristics of exposure times and frequencies, and various rankings of the relative role of individual chemicals. Though all results are based on in silico assessments, the prospective land use–based approach applied in the present study yields useful insights for simplifying and assessing potential ecological risks of chemical mixtures and can therefore be useful for catchment‐management decisions. Environ Toxicol Chem 2018;37:715–728. © 2017 The Authors

Application of WRF/Chem over the Continental U.S. under the AQMEII Phase II: Part 2. Evaluation of 2010 Application and Responses of Air Quality and Meteorology-Chemistry Interactions to Changes in Emissions and Meteorology from 2006 to 2010

Science.gov (United States)

The Weather Research and Forecasting model with Chemistry (WRF/Chem) simulation with the 2005 Carbon Bond (CB05) gas-phase mechanism coupled to the Modal for Aerosol Dynamics for Europe (MADE) and the Volatility Basis Set (VBS) approach for secondary organic aerosol (SOA) (MADE/V...

In situ calibration using univariate analyses based on the onboard ChemCam targets: first prediction of Martian rock and soil compositions

Energy Technology Data Exchange (ETDEWEB)

Fabre, C. [GeoRessources lab, Université de Lorraine, Nancy (France); Cousin, A.; Wiens, R.C. [Los Alamos National Laboratory, Los Alamos, NM (United States); Ollila, A. [University of NM, Albuquerque (United States); Gasnault, O.; Maurice, S. [IRAP, Toulouse (France); Sautter, V. [Museum National d' Histoire Naturelle, Paris (France); Forni, O.; Lasue, J. [IRAP, Toulouse (France); Tokar, R.; Vaniman, D. [Planetary Science Institute, Tucson, AZ (United States); Melikechi, N. [Delaware State University (United States)

2014-09-01

Curiosity rover landed on August 6th, 2012 in Gale Crater, Mars and it possesses unique analytical capabilities to investigate the chemistry and mineralogy of the Martian soil. In particular, the LIBS technique is being used for the first time on another planet with the ChemCam instrument, and more than 75,000 spectra have been returned in the first year on Mars. Curiosity carries body-mounted calibration targets specially designed for the ChemCam instrument, some of which are homgeneous glasses and others that are fine-grained glass-ceramics. We present direct calibrations, using these onboard standards to infer elements and element ratios by ratioing relative peak areas. As the laser spot size is around 300 μm, the LIBS technique provides measurements of the silicate glass compositions representing homogeneous material and measurements of the ceramic targets that are comparable to fine-grained rock or soil. The laser energy and the auto-focus are controlled for all sequences used for calibration. The univariate calibration curves present relatively to very good correlation coefficients with low RSDs for major and ratio calibrations. Trace element calibration curves (Li, Sr, and Mn), down to several ppm, can be used as a rapid tool to draw attention to remarkable rocks and soils along the traverse. First comparisons to alpha-particle X-ray spectroscopy (APXS) data, on selected targets, show good agreement for most elements and for Mg# and Al/Si estimates. SiO{sub 2} estimates using univariate cannot be yet used. Na{sub 2}O and K{sub 2}O estimates are relevant for high alkali contents, but probably under estimated due to the CCCT initial compositions. Very good results for CaO and Al{sub 2}O{sub 3} estimates and satisfactory results for FeO are obtained. - Highlights: • In situ LIBS univariate calibrations are done using the Curiosity onboard standards. • Major and minor element contents can be rapidly obtained. • Trace element contents can be used as a

Radiative effects of black carbon aerosols on Indian monsoon: a study using WRF-Chem model

Science.gov (United States)

Soni, Pramod; Tripathi, Sachchida Nand; Srivastava, Rajesh

2018-04-01

The Weather Research and Forecasting model with Chemistry (WRF-Chem) is utilized to examine the radiative effects of black carbon (BC) aerosols on the Indian monsoon, for the year 2010. Five ensemble simulations with different initial conditions (1st to 5th December, 2009) were performed and simulation results between 1st January, 2010 to 31st December, 2010 were used for analysis. Most of the BC which stays near the surface during the pre-monsoon season gets transported to higher altitudes with the northward migration of the Inter Tropical Convergence Zone (ITCZ) during the monsoon season. In both the seasons, strong negative SW anomalies are present at the surface along with positive anomalies in the atmosphere, which results in the surface cooling and lower tropospheric heating, respectively. During the pre-monsoon season, lower troposphere heating causes increased convection and enhanced meridional wind circulation, bringing moist air from Indian Ocean and Bay of Bengal to the North-East India, leading to increased rainfall there. However, during the monsoon season, along with cooling over the land regions, a warming over the Bay of Bengal is simulated. This differential heating results in an increased westerly moisture flux anomaly over central India, leading to increased rainfall over northern parts of India but decreased rainfall over southern parts. Decreased rainfall over southern India is also substantiated by the presence of increased evaporation over Bay of Bengal and decrease over land regions.

A WRF-Chem model study of the impact of VOCs emission of a huge petro-chemical industrial zone on the summertime ozone in Beijing, China

Science.gov (United States)

Wei, Wei; Lv, Zhao Feng; Li, Yue; Wang, Li Tao; Cheng, Shuiyuan; Liu, Huan

2018-02-01

In China, petro-chemical manufacturing plants generally gather in the particular industrial zone defined as PIZ in some cities, and distinctly influence the air quality of these cities for their massive VOCs emissions. This study aims to quantify the local and regional impacts of PIZ VOCs emission and its relevant reduction policy on the surface ozone based on WRF-Chem model, through the case study of Beijing. Firstly, the model simulation under the actual precursors' emissions over Beijing region for July 2010 is conducted and evaluated, which meteorological and chemical predictions both within the thresholds for satisfactory model performance. Then, according to simulated H2O2/HNO3 ratio, the nature of photochemical ozone formation over Beijing is decided, the VOCs-sensitive regime over the urban areas, NOx-sensitive regime over the northern and western rural areas, and both VOCssbnd and NOx-mixed sensitive regime over the southern and eastern rural areas. Finally, a 30% VOCs reduction scenario (RS) and a 100% VOCs reduction scenario (ZS) for Beijing PIZ are additional simulated by WRF-Chem. The sensitivity simulations imply that the current 30% reduction policy would bring about an O3 increase in the southern and western areas (by +4.7 ppb at PIZ site and +2.1 ppb at LLH station), and an O3 decrease in the urban center (by -1.7 ppb at GY station and -2.5 ppb at DS station) and in the northern and eastern areas (by -1.2 ppb at MYX station), mainly through interfering with the circulation of atmospheric HOx radicals. While the contribution of the total VOCs emission of PIZ to ozone is greatly prominent in the PIZ and its surrounding areas along south-north direction (12.7% at PIZ site on average), but slight in the other areas of Beijing (<3% in other four stations on average).

PREP-CHEM-SRC – 1.0: a preprocessor of trace gas and aerosol emission fields for regional and global atmospheric chemistry models

Directory of Open Access Journals (Sweden)

S. R. Freitas

2011-05-01

Full Text Available The preprocessor PREP-CHEM-SRC presented in the paper is a comprehensive tool aiming at preparing emission fields of trace gases and aerosols for use in atmospheric-chemistry transport models. The considered emissions are from the most recent databases of urban/industrial, biogenic, biomass burning, volcanic, biofuel use and burning from agricultural waste sources. For biomass burning, emissions can be also estimated directly from satellite fire detections using a fire emission model included in the tool. The preprocessor provides emission fields interpolated onto the transport model grid. Several map projections can be chosen. The inclusion of these emissions in transport models is also presented. The preprocessor is coded using Fortran90 and C and is driven by a namelist allowing the user to choose the type of emissions and the databases.

Comparison of Current Recommended Regimens of Atropinization in Organophosphate Poisoning

OpenAIRE

Connors, Nicholas J.; Harnett, Zachary H.; Hoffman, Robert S.

2013-01-01

Atropine is the mainstay of therapy in organophosphate (OP) toxicity, though research and consensus on dosing is lacking. In 2004, as reported by Eddleston et al. (J Toxicol Clin Toxicol 42(6):865-75, 2004), they noted variation in recommended regimens. We assessed revisions of original references, additional citations, and electronic sources to determine the current variability in atropine dosing recommendations. Updated editions of references from Eddleston et al.’s work, texts of Internal ...

Quantifying sources of elemental carbon over the Guanzhong Basin of China: A consistent network of measurements and WRF-Chem modeling

International Nuclear Information System (INIS)

Li, Nan; He, Qingyang; Tie, Xuexi; Cao, Junji; Liu, Suixin; Wang, Qiyuan; Li, Guohui; Huang, Rujin; Zhang, Qiang

2016-01-01

We conducted a year-long WRF-Chem (Weather Research and Forecasting Chemical) model simulation of elemental carbon (EC) aerosol and compared the modeling results to the surface EC measurements in the Guanzhong (GZ) Basin of China. The main goals of this study were to quantify the individual contributions of different EC sources to EC pollution, and to find the major cause of the EC pollution in this region. The EC measurements were simultaneously conducted at 10 urban, rural, and background sites over the GZ Basin from May 2013 to April 2014, and provided a good base against which to evaluate model simulation. The model evaluation showed that the calculated annual mean EC concentration was 5.1 μgC m −3 , which was consistent with the observed value of 5.3 μgC m −3 . Moreover, the model result also reproduced the magnitude of measured EC in all seasons (regression slope = 0.98–1.03), as well as the spatial and temporal variations (r = 0.55–0.78). We conducted several sensitivity studies to quantify the individual contributions of EC sources to EC pollution. The sensitivity simulations showed that the local and outside sources contributed about 60% and 40% to the annual mean EC concentration, respectively, implying that local sources were the major EC pollution contributors in the GZ Basin. Among the local sources, residential sources contributed the most, followed by industry and transportation sources. A further analysis suggested that a 50% reduction of industry or transportation emissions only caused a 6% decrease in the annual mean EC concentration, while a 50% reduction of residential emissions reduced the winter surface EC concentration by up to 25%. In respect to the serious air pollution problems (including EC pollution) in the GZ Basin, our findings can provide an insightful view on local air pollution control strategies. - Highlights: • A yearlong WRF-Chem simulation is conducted to identify sources of the EC pollution. • A network of

Modeling regional air quality and climate: improving organic aerosol and aerosol activation processes in WRF/Chem version 3.7.1

Science.gov (United States)

Yahya, Khairunnisa; Glotfelty, Timothy; Wang, Kai; Zhang, Yang; Nenes, Athanasios

2017-06-01

Air quality and climate influence each other through the uncertain processes of aerosol formation and cloud droplet activation. In this study, both processes are improved in the Weather, Research and Forecasting model with Chemistry (WRF/Chem) version 3.7.1. The existing Volatility Basis Set (VBS) treatments for organic aerosol (OA) formation in WRF/Chem are improved by considering the following: the secondary OA (SOA) formation from semi-volatile primary organic aerosol (POA), a semi-empirical formulation for the enthalpy of vaporization of SOA, and functionalization and fragmentation reactions for multiple generations of products from the oxidation of VOCs. Over the continental US, 2-month-long simulations (May to June 2010) are conducted and results are evaluated against surface and aircraft observations during the Nexus of Air Quality and Climate Change (CalNex) campaign. Among all the configurations considered, the best performance is found for the simulation with the 2005 Carbon Bond mechanism (CB05) and the VBS SOA module with semivolatile POA treatment, 25 % fragmentation, and the emissions of semi-volatile and intermediate volatile organic compounds being 3 times the original POA emissions. Among the three gas-phase mechanisms (CB05, CB6, and SAPRC07) used, CB05 gives the best performance for surface ozone and PM2. 5 concentrations. Differences in SOA predictions are larger for the simulations with different VBS treatments (e.g., nonvolatile POA versus semivolatile POA) compared to the simulations with different gas-phase mechanisms. Compared to the simulation with CB05 and the default SOA module, the simulations with the VBS treatment improve cloud droplet number concentration (CDNC) predictions (normalized mean biases from -40.8 % to a range of -34.6 to -27.7 %), with large differences between CB05-CB6 and SAPRC07 due to large differences in their OH and HO2 predictions. An advanced aerosol activation parameterization based on the Fountoukis and Nenes

Evaluation of aerosol optical properties of GEOS-Chem over East Asia during the DRAGON-Asia 2012 campaign

Science.gov (United States)

Jo, D. S.; Park, R.; Kim, J.

2015-12-01

A nested version of 3-D chemical transport model (GEOS-Chem v9-01-02) is evaluated over East Asia during the Distributed Regional Aerosol Gridded Observation Networks (DRAGON)-Asia 2012 campaign period, focusing on fine-mode aerosol optical depth (fAOD) and single scattering albedo (SSA). Both are important to assess the effect of anthropogenic aerosols on climate. We compare the daily mean simulated optical properties of aerosols with the observations from DRAGON-Asia campaign for March-May, 2012 (provided in level 2.0: cloud screened and quality assured). We find that the model reproduces the observed daily variability of fAOD (R=0.67), but overestimates the magnitude by 30%, which is in general consistent with other global model comparisons from ACCMIP. However, a significant high bias in the model is found compared to the observed SSA at 440 nm, which is important for determining the sign of aerosol radiative forcing. In order to understand causes for this gap we conduct several sensitivity tests by changing source magnitudes and input parameters of aerosols, affecting the aerosol optical properties under various atmospheric conditions, which allows us to reduce the gap and to find the optimal values in the model.

El Centro de Investigaciones Toxicológicas

OpenAIRE

Castro, Gerardo Daniel

2016-01-01

La vida de nuestro laboratorio es tan extensa como la mía, ¡pues ambos nacimos el mismo año! Y no son pocos los años que llevo trabajando aquí, desde 1983... Los tiempos más felices de mi actividad profesional han sido aquellos cuando los tres, mis viejos y yo, trabajábamos juntos en el CEITOX. No solamente por el placer de investigar, pensar experimentos, discutir resultados (en el laboratorio y en casa) si no también por todas aquellas oportunidades compartidas conociendo lugares hermosos e...

Hazard assessment of exhaust emissions - The next generation of fast and reliable tools for in vitro screening

Science.gov (United States)

Rothen-Rutishauser, B.

2017-12-01

Hazard assessment of exhaust emissions - The next generation of fast and reliable tools for in vitro screening Barbara Rothen-Rutishauser Adolphe Merkle Institute, University of Fribourg, Switzerland; barbara.rothen@unifr.ch Pollution by vehicles is a major problem for the environment due to the various components in the exhaust gasses that are emitted into the atmosphere. A large number of epidemiological studies demonstrate the profound impact of vehicle emissions upon human health [1-3]. Such studies however, are unable to attribute a given subset of emissions to a certain adverse effect, which renders decision making difficult. Standardized protocols for exhaust toxicity assessment are lacking and it relies in many aspects on epidemiological and in vivo studies (animals), which are very time and cost-intensive and suffer from considerable ethical issues. An overview about the current state of research and clinical aspects in the field, as well as about the development of sophisticated in vitro approaches mimicking the inhalation of airborne particles / exhaust for the toxicological testing of engine emissions will be provided. Data will be presented that show that the combination of an air-liquid exposure system and 3D lung-cell culture model offers an adequate tool for fast and reliable investigations of complete exhaust toxicity as well as the effects of particulate fraction [4,5]. This approach yields important results for novel and improved emission technologies in the early stages of product development. [1] Donaldson et al. Part Fibre Toxicol 2005, 2: 10. [2] Ghio et al. J Toxicol Environ Health B Crit Rev 2012, 15: 1-21. [3] Peters et al. Res Rep Health Eff Inst 2009, 5-77. [4] Bisig et al. Emiss Control Sci Technol 2015, 1: 237-246. [5] Steiner et al. Atmos Environ 2013, 81: 380-388.

Persistent Neural Membrane Protein Misregulation Following Neurotoxicant Exposure

Science.gov (United States)

2015-12-01

Pope (2002). "Age-related effects of chlorpyrifos on muscarinic receptor-mediated signaling in rat cortex ." Arch Toxicol 75(11-12): 676-684. Zhang...M.F., 2010. Accumulation of pyrethroid compounds in primary cultures from rat cortex . Toxicol. In Vitro 24 (7), 2053–2057. Shafer, T.J., Meyer, D.A...2014). "P2Y1 receptor-mediated potentiation of inspiratory motor output in neonatal rat in vitro." J Physiol 592(Pt 14): 3089-3111. Andrade, R

Power plant fuel switching and air quality in a tropical, forested environment

Science.gov (United States)

Medeiros, Adan S. S.; Calderaro, Gisele; Guimarães, Patricia C.; Magalhaes, Mateus R.; Morais, Marcos V. B.; Rafee, Sameh A. A.; Ribeiro, Igor O.; Andreoli, Rita V.; Martins, Jorge A.; Martins, Leila D.; Martin, Scot T.; Souza, Rodrigo A. F.

2017-07-01

How a changing energy matrix for electricity production affects air quality is considered for an urban region in a tropical, forested environment. Manaus, the largest city in the central Amazon Basin of Brazil, is in the process of changing its energy matrix for electricity production from fuel oil and diesel to natural gas over an approximately 10-year period, with a minor contribution by hydropower. Three scenarios of urban air quality, specifically afternoon ozone concentrations, were simulated using the Weather Research and Forecasting (WRF-Chem) model. The first scenario used fuel oil and diesel for electricity production, which was the reality in 2008. The second scenario was based on the fuel mix from 2014, the most current year for which data were available. The third scenario considered nearly complete use of natural gas for electricity production, which is the anticipated future, possibly for 2018. For each case, inventories of anthropogenic emissions were based on electricity generation, refinery operations, and transportation. Transportation and refinery operations were held constant across the three scenarios to focus on effects of power plant fuel switching in a tropical context. The simulated NOx and CO emissions for the urban region decrease by 89 and 55 %, respectively, after the complete change in the energy matrix. The results of the simulations indicate that a change to natural gas significantly decreases maximum afternoon ozone concentrations over the population center, reducing ozone by > 70 % for the most polluted days. The sensitivity of ozone concentrations to the fuel switchover is consistent with a NOx-limited regime, as expected for a tropical forest having high emissions of biogenic volatile organic compounds, high water vapor concentrations, and abundant solar radiation. There are key differences in a shifting energy matrix in a tropical, forested environment compared to other world environments. Policies favoring the burning of

Power plant fuel switching and air quality in a tropical, forested environment

Directory of Open Access Journals (Sweden)

A. S. S. Medeiros

2017-07-01

Full Text Available How a changing energy matrix for electricity production affects air quality is considered for an urban region in a tropical, forested environment. Manaus, the largest city in the central Amazon Basin of Brazil, is in the process of changing its energy matrix for electricity production from fuel oil and diesel to natural gas over an approximately 10-year period, with a minor contribution by hydropower. Three scenarios of urban air quality, specifically afternoon ozone concentrations, were simulated using the Weather Research and Forecasting (WRF-Chem model. The first scenario used fuel oil and diesel for electricity production, which was the reality in 2008. The second scenario was based on the fuel mix from 2014, the most current year for which data were available. The third scenario considered nearly complete use of natural gas for electricity production, which is the anticipated future, possibly for 2018. For each case, inventories of anthropogenic emissions were based on electricity generation, refinery operations, and transportation. Transportation and refinery operations were held constant across the three scenarios to focus on effects of power plant fuel switching in a tropical context. The simulated NOx and CO emissions for the urban region decrease by 89 and 55 %, respectively, after the complete change in the energy matrix. The results of the simulations indicate that a change to natural gas significantly decreases maximum afternoon ozone concentrations over the population center, reducing ozone by > 70 % for the most polluted days. The sensitivity of ozone concentrations to the fuel switchover is consistent with a NOx-limited regime, as expected for a tropical forest having high emissions of biogenic volatile organic compounds, high water vapor concentrations, and abundant solar radiation. There are key differences in a shifting energy matrix in a tropical, forested environment compared to other world environments. Policies

Accounting for model error in air quality forecasts: an application of 4DEnVar to the assimilation of atmospheric composition using QG-Chem 1.0

Directory of Open Access Journals (Sweden)

E. Emili

2016-11-01

Full Text Available Model errors play a significant role in air quality forecasts. Accounting for them in the data assimilation (DA procedures is decisive to obtain improved forecasts. We address this issue using a reduced-order coupled chemistry–meteorology model based on quasi-geostrophic dynamics and a detailed tropospheric chemistry mechanism, which we name QG-Chem. This model has been coupled to the software library for the data assimilation Object Oriented Prediction System (OOPS and used to assess the potential of the 4DEnVar algorithm for air quality analyses and forecasts. The assets of 4DEnVar include the possibility to deal with multivariate aspects of atmospheric chemistry and to account for model errors of a generic type. A simple diagnostic procedure for detecting model errors is proposed, based on the 4DEnVar analysis and one additional model forecast. A large number of idealized data assimilation experiments are shown for several chemical species of relevance for air quality forecasts (O3, NOx, CO and CO2 with very different atmospheric lifetimes and chemical couplings. Experiments are done both under a perfect model hypothesis and including model error through perturbation of surface chemical emissions. Some key elements of the 4DEnVar algorithm such as the ensemble size and localization are also discussed. A comparison with results of 3D-Var, widely used in operational centers, shows that, for some species, analysis and next-day forecast errors can be halved when model error is taken into account. This result was obtained using a small ensemble size, which remains affordable for most operational centers. We conclude that 4DEnVar has a promising potential for operational air quality models. We finally highlight areas that deserve further research for applying 4DEnVar to large-scale chemistry models, i.e., localization techniques, propagation of analysis covariance between DA cycles and treatment for chemical nonlinearities. QG-Chem can provide a

Coupled sensor/platform control design for low-level chemical detection with position-adaptive micro-UAVs

Science.gov (United States)

Goodwin, Thomas; Carr, Ryan; Mitra, Atindra K.; Selmic, Rastko R.

2009-05-01

We discuss the development of Position-Adaptive Sensors [1] for purposes for detecting embedded chemical substances in challenging environments. This concept is a generalization of patented Position-Adaptive Radar Concepts developed at AFRL for challenging conditions such as urban environments. For purposes of investigating the detection of chemical substances using multiple MAV (Micro-UAV) platforms, we have designed and implemented an experimental testbed with sample structures such as wooden carts that contain controlled leakage points. Under this general concept, some of the members of a MAV swarm can serve as external position-adaptive "transmitters" by blowing air over the cart and some of the members of a MAV swarm can serve as external position-adaptive "receivers" that are equipped with chemical or biological (chem/bio) sensors that function as "electronic noses". The objective can be defined as improving the particle count of chem/bio concentrations that impinge on a MAV-based position-adaptive sensor that surrounds a chemical repository, such as a cart, via the development of intelligent position-adaptive control algorithms. The overall effect is to improve the detection and false-alarm statistics of the overall system. Within the major sections of this paper, we discuss a number of different aspects of developing our initial MAV-Based Sensor Testbed. This testbed includes blowers to simulate position-adaptive excitations and a MAV from Draganfly Innovations Inc. with stable design modifications to accommodate our chem/bio sensor boom design. We include details with respect to several critical phases of the development effort including development of the wireless sensor network and experimental apparatus, development of the stable sensor boom for the MAV, integration of chem/bio sensors and sensor node onto the MAV and boom, development of position-adaptive control algorithms and initial tests at IDCAST (Institute for the Development and

Transcriptional and cellular effects of benzotriazole UV stabilizers UV-234 and UV-328 in the freshwater invertebrates Chlamydomonas reinhardtii and Daphnia magna.

Science.gov (United States)

Giraudo, Maeva; Cottin, Guillaume; Esperanza, Marta; Gagnon, Pierre; Silva, Amila O De; Houde, Magali

2017-12-01

Benzotriazole ultra violet stabilizers (BZT-UVs) are compounds used in many applications and products to prevent photochemical degradation. Despite their widespread presence in aquatic ecosystems and persistence in the environment, there are very limited data on their effects and toxicity, and their modes of action remain largely unknown. The objectives of the present study were to evaluate the chronic effects of 2 BZT-UVs, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (UV-234) and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV-328), on the freshwater green algae Chlamydomonas reinhardtii and the freshwater crustacean Daphnia magna. Organisms were exposed to 0.01 and 10 μg/L of UV-234, UV-328, as well as a mixture of the 2 compounds. Life-history endpoints (viability, reproduction, and growth) and oxidative stress-related biomarkers (gene transcription, reactive oxygen species [ROS] production, and lipid peroxidation) were measured. Daphnia magna growth, reproduction, and gene transcription were not impacted by 21-d individual or mixed exposure. After 96-h of exposure, no differences were observed on the cellular viability of C. reinhardtii for either of the 2 BZT-UVs. In the algae, results showed increased ROS production in response to UV-328 and lipid peroxidation following exposure to UV-234. Synergistic effects of the 2 BZT-UVs were evident at the transcriptional level with 2 to 6 times up-regulation of glutathione peroxidase (gp x ) in response to the mixture for all treatment conditions. The transcription of superoxide dismutase (sod), catalase (cat), and ascorbic peroxidase (apx) was also regulated by UV-234 and UV-328 in the green algae, most likely as a result of ROS production and lipid peroxidation. Results from the present study suggest potential impacts of UV-234 and UV-328 exposure on the antioxidant defense system in C. reinhardtii. Environ Toxicol Chem 2017;36:3333-3342. © 2017 Crown in the Right of Canada. Published by

Comparing the sensitivity of chlorophytes, cyanobacteria, and diatoms to major-use antibiotics.

Science.gov (United States)

Guo, Jiahua; Selby, Katherine; Boxall, Alistair B A

2016-10-01

The occurrence of antibiotic residues in the aquatic environment is an emerging concern. In contrast to daphnia and fish, algae are known to be particularly sensitive to antibiotic exposure. However, to date, a systematic evaluation of the sensitivity of different algal species to antibiotics has not been performed. The aim of the present study was therefore to explore the sensitivity of a battery of algal species toward antibiotic exposures. The present study investigated the growth inhibition effects of 3 major-use antibiotics, tylosin, lincomycin, and trimethoprim, on 7 algal species from the chlorophyte, cyanobacteria, and diatom groups. Based on median effective concentration (EC50) values, cyanobacteria (EC50 = 0.095-0.13 μmol/L) were found to be the most sensitive group to lincomycin followed by chlorophytes (EC50 = 7.36-225.73 μmol/L) and diatoms (EC50 > 225.73 μmol/L). Cyanobacteria were also the most sensitive group to tylosin (EC50 = 0.09-0.092 μmol/L), but, for this compound, diatoms (EC50 = 1.33-5.7 μmol/L) were more sensitive than chlorophytes (EC50 = 4.14-81.2 μmol/L). Diatoms were most sensitive to trimethoprim (EC50 = 7.36-74.61 μmol/L), followed by cyanobacteria (EC50 = 315.78-344.45 μmol/L), and chlorophytes (EC50 > 344.45 μmol/L) for trimethoprim. Although these results partly support the current approach to regulatory environmental risk assessment (whereby cyanobacterial species are recommended for use with antibiotic compounds), they indicate that for some antibiotics this group might not be the most appropriate test organism. It is therefore suggested that environmental risk assessments consider data on 3 algal groups (chlorophytes, cyanobacteria, and diatoms) and use test species from these groups, which are consistently found to be the most sensitive (Pseudokirchneriella subcapitata, Anabaena flos-aquae, and Navicula pelliculosa). Environ Toxicol Chem 2016;35:2587-2596. © 2016 SETAC. �

Comparison of the applicability of commercial computer programs to study the thermodynamic stability of metal oxides

International Nuclear Information System (INIS)

Koukkari, P.; Olin, M.; Laitinen, T.; Sippola, H.

1999-04-01

The oxide films formed on primary circuit surfaces incorporate radioactive species from the coolant and influence different corrosion phenomena in nuclear power plants. One approach to improve the understanding on the formation and properties of these oxide films is to evaluate their thermodynamic stability. The aim of this work was to compare and demonstrate the applicability of different commercial thermodynamic computer programs to model the deposition of oxides containing iron, chromium and/or nickel in various nuclear power plant environments. The programs considered in this evaluation comprised the EQ3/6 program and a product group including such products as ChemSage, HSC (including SOLGASMIX and GIBBS), H+PLUS and ChemSheet. In the group the transfer of data between different products is relatively easy. The goal was to find out which programs can be applied to evaluate the stability of oxide films, but not to assess the absolute accuracy of the calculations. The evaluation was done by means of applying the programs to calculate the stability of pure and mixed oxides of iron, nickel and chromium on stainless steel both in WWER and BWR conditions at different temperatures and coolant compositions. The comparison showed that EQ3/6 is suitable for most thermodynamic calculations. EQ3/6 can be characterised as a professional tool, for which no commercial training is available. ChemSage is a versatile and reliable program, which can be well used together with HSC and H+PLUS. ChemSage is mainly a professional tool, while HSC is easier to operate by an occasional user. Commercial training and support is available for both ChemSage and HSC. ChemSheet has been designed to utilise the properties of ChemSage in a user-friendly spreadsheet environment. All the products tested calculate thermodynamic equilibrium. Thus they are suitable to characterise such conditions in which the formation of a certain phase is or becomes possible. On the other hand, the modelling of the

Comparison of the applicability of commercial computer programs to study the thermodynamic stability of metal oxides; Vertailu kaupallisten laskentaohjelmien soveltuvuudesta metallioksidien termodynaamiseen stabiilisuustarkasteluun

Energy Technology Data Exchange (ETDEWEB)

Koukkari, P.; Olin, M. [VTT Chemical Technology, Espoo (Finland); Laitinen, T. [VTT Manufacturing Technology, Espoo (Finland); Sippola, H. [GEM Systems Oy (Finland)

1999-04-01

The oxide films formed on primary circuit surfaces incorporate radioactive species from the coolant and influence different corrosion phenomena in nuclear power plants. One approach to improve the understanding on the formation and properties of these oxide films is to evaluate their thermodynamic stability. The aim of this work was to compare and demonstrate the applicability of different commercial thermodynamic computer programs to model the deposition of oxides containing iron, chromium and/or nickel in various nuclear power plant environments. The programs considered in this evaluation comprised the EQ3/6 program and a product group including such products as ChemSage, HSC (including SOLGASMIX and GIBBS), H+PLUS and ChemSheet. In the group the transfer of data between different products is relatively easy. The goal was to find out which programs can be applied to evaluate the stability of oxide films, but not to assess the absolute accuracy of the calculations. The evaluation was done by means of applying the programs to calculate the stability of pure and mixed oxides of iron, nickel and chromium on stainless steel both in WWER and BWR conditions at different temperatures and coolant compositions. The comparison showed that EQ3/6 is suitable for most thermodynamic calculations. EQ3/6 can be characterised as a professional tool, for which no commercial training is available. ChemSage is a versatile and reliable program, which can be well used together with HSC and H+PLUS. ChemSage is mainly a professional tool, while HSC is easier to operate by an occasional user. Commercial training and support is available for both ChemSage and HSC. ChemSheet has been designed to utilise the properties of ChemSage in a user-friendly spreadsheet environment. All the products tested calculate thermodynamic equilibrium. Thus they are suitable to characterise such conditions in which the formation of a certain phase is or becomes possible. On the other hand, the modelling of the

Thimerosal and children’s neurodevelopmental disorders

OpenAIRE

Maya, Luis; Luna, Flora

2006-01-01

Se evalúa la relación causal entre el timerosal (etilmercurio), como preservante en las vacunas pediátricas, y el incremento de casos de enfermedades del neurodesarrollo infantil, como consecuencia de la ampliación de los esquemas de inmunización. Se revisó la información científica, relacionando el timerosal y las evidencias que permitan evaluar una posible asociación causal, con estudios epidemiológicos, ecológicos, biomoleculares y toxicológicos, de bioseguridad, toxicológicos fetales y so...

El timerosal y las enfermedades del neurodesarrollo infantil

OpenAIRE

Luis Maya; Flora Luna

2006-01-01

Se evalúa la relación causal entre el timerosal (etilmercurio), como preservante en las vacunas pediátricas, y el incremento de casos de enfermedades del neurodesarrollo infantil, como consecuencia de la ampliación de los esquemas de inmunización. Se revisó la información científica, relacionando el timerosal y las evidencias que permitan evaluar una posible asociación causal, con estudios epidemiológicos, ecológicos, biomoleculares y toxicológicos, de bioseguridad, toxicológicos fetales y so...

Impact of vehicular emissions on the formation of fine particles in the Sao Paulo Metropolitan Area: a numerical study with the WRF-Chem model

Directory of Open Access Journals (Sweden)

A. Vara-Vela

2016-01-01

Full Text Available The objective of this work is to evaluate the impact of vehicular emissions on the formation of fine particles (PM2.5;  ≤  2.5 µm in diameter in the Sao Paulo Metropolitan Area (SPMA in Brazil, where ethanol is used intensively as a fuel in road vehicles. The Weather Research and Forecasting with Chemistry (WRF-Chem model, which simulates feedbacks between meteorological variables and chemical species, is used as a photochemical modelling tool to describe the physico-chemical processes leading to the evolution of number and mass size distribution of particles through gas-to-particle conversion. A vehicular emission model based on statistical information of vehicular activity is applied to simulate vehicular emissions over the studied area. The simulation has been performed for a 1-month period (7 August–6 September 2012 to cover the availability of experimental data from the NUANCE-SPS (Narrowing the Uncertainties on Aerosol and Climate Changes in Sao Paulo State project that aims to characterize emissions of atmospheric aerosols in the SPMA. The availability of experimental measurements of atmospheric aerosols and the application of the WRF-Chem model made it possible to represent some of the most important properties of fine particles in the SPMA such as the mass size distribution and chemical composition, besides allowing us to evaluate its formation potential through the gas-to-particle conversion processes. Results show that the emission of primary gases, mostly from vehicles, led to a production of secondary particles between 20 and 30 % in relation to the total mass concentration of PM2.5 in the downtown SPMA. Each of PM2.5 and primary natural aerosol (dust and sea salt contributed with 40–50 % of the total PM10 (i.e. those  ≤  10 µm in diameter concentration. Over 40 % of the formation of fine particles, by mass, was due to the emission of hydrocarbons, mainly aromatics. Furthermore, an increase in the

Impact of vehicular emissions on the formation of fine particles in the Sao Paulo Metropolitan Area: a numerical study with the WRF-Chem model

Science.gov (United States)

Vara-Vela, A.; Andrade, M. F.; Kumar, P.; Ynoue, R. Y.; Muñoz, A. G.

2016-01-01

The objective of this work is to evaluate the impact of vehicular emissions on the formation of fine particles (PM2.5; ≤ 2.5 µm in diameter) in the Sao Paulo Metropolitan Area (SPMA) in Brazil, where ethanol is used intensively as a fuel in road vehicles. The Weather Research and Forecasting with Chemistry (WRF-Chem) model, which simulates feedbacks between meteorological variables and chemical species, is used as a photochemical modelling tool to describe the physico-chemical processes leading to the evolution of number and mass size distribution of particles through gas-to-particle conversion. A vehicular emission model based on statistical information of vehicular activity is applied to simulate vehicular emissions over the studied area. The simulation has been performed for a 1-month period (7 August-6 September 2012) to cover the availability of experimental data from the NUANCE-SPS (Narrowing the Uncertainties on Aerosol and Climate Changes in Sao Paulo State) project that aims to characterize emissions of atmospheric aerosols in the SPMA. The availability of experimental measurements of atmospheric aerosols and the application of the WRF-Chem model made it possible to represent some of the most important properties of fine particles in the SPMA such as the mass size distribution and chemical composition, besides allowing us to evaluate its formation potential through the gas-to-particle conversion processes. Results show that the emission of primary gases, mostly from vehicles, led to a production of secondary particles between 20 and 30 % in relation to the total mass concentration of PM2.5 in the downtown SPMA. Each of PM2.5 and primary natural aerosol (dust and sea salt) contributed with 40-50 % of the total PM10 (i.e. those ≤ 10 µm in diameter) concentration. Over 40 % of the formation of fine particles, by mass, was due to the emission of hydrocarbons, mainly aromatics. Furthermore, an increase in the number of small particles impaired the

Simulation of West African air pollution during the DACCIWA experiment with the GEOS-Chem West African regional model.

Science.gov (United States)

Morris, Eleanor; Evans, Mathew

2017-04-01

Pollutant emissions from West African cities are forecast to increase rapidly in future years because of extensive economic and population growth, together with poorly regulated industrialisation and urbanisation. Observational constraints in this region are few, leading to poor understanding of present-day air pollution in this region. To increase our understanding of the processes controlling air pollutants over the region, airborne observations were made from three research aircraft based out of Lomé, Togo during the DACCIWA field campaign in June-July 2016. A new 0.25x0.3125 degree West Africa regional version of the GEOS-Chem offline chemical transport model has also been developed to explore the processes controlling pollutants over the region. We evaluate the model using the aircraft data and focus on primary (CO, SO2, NOx, VOCs) and secondary pollutants (O3, aerosol). We find significant differences between the model and the measurements for certain primary compounds which is indicative of significant uncertainties in the base (EDGAR) emissions. For CO (a general tracer of pollution) we evaluate the role of different emissions sources (transport, low temperature combustion, power generation) in determining its concentration in the region. We conclude that the leading cause of uncertainty in our simulation is associated with the emissions datasets and explore the impact of using differing datasets.

Surface Pressure Dependencies in the GEOS-Chem-Adjoint System and the Impact of the GEOS-5 Surface Pressure on CO2 Model Forecast

Science.gov (United States)

Lee, Meemong; Weidner, Richard

2016-01-01

In the GEOS-Chem Adjoint (GCA) system, the total (wet) surface pressure of the GEOS meteorology is employed as dry surface pressure, ignoring the presence of water vapor. The Jet Propulsion Laboratory (JPL) Carbon Monitoring System (CMS) research team has been evaluating the impact of the above discrepancy on the CO2 model forecast and the CO2 flux inversion. The JPL CMS research utilizes a multi-mission assimilation framework developed by the Multi-Mission Observation Operator (M2O2) research team at JPL extending the GCA system. The GCA-M2O2 framework facilitates mission-generic 3D and 4D-variational assimilations streamlining the interfaces to the satellite data products and prior emission inventories. The GCA-M2O2 framework currently integrates the GCA system version 35h and provides a dry surface pressure setup to allow the CO2 model forecast to be performed with the GEOS-5 surface pressure directly or after converting it to dry surface pressure.

Modeling regional air quality and climate: improving organic aerosol and aerosol activation processes in WRF/Chem version 3.7.1

Directory of Open Access Journals (Sweden)

K. Yahya

2017-06-01

Full Text Available Air quality and climate influence each other through the uncertain processes of aerosol formation and cloud droplet activation. In this study, both processes are improved in the Weather, Research and Forecasting model with Chemistry (WRF/Chem version 3.7.1. The existing Volatility Basis Set (VBS treatments for organic aerosol (OA formation in WRF/Chem are improved by considering the following: the secondary OA (SOA formation from semi-volatile primary organic aerosol (POA, a semi-empirical formulation for the enthalpy of vaporization of SOA, and functionalization and fragmentation reactions for multiple generations of products from the oxidation of VOCs. Over the continental US, 2-month-long simulations (May to June 2010 are conducted and results are evaluated against surface and aircraft observations during the Nexus of Air Quality and Climate Change (CalNex campaign. Among all the configurations considered, the best performance is found for the simulation with the 2005 Carbon Bond mechanism (CB05 and the VBS SOA module with semivolatile POA treatment, 25 % fragmentation, and the emissions of semi-volatile and intermediate volatile organic compounds being 3 times the original POA emissions. Among the three gas-phase mechanisms (CB05, CB6, and SAPRC07 used, CB05 gives the best performance for surface ozone and PM2. 5 concentrations. Differences in SOA predictions are larger for the simulations with different VBS treatments (e.g., nonvolatile POA versus semivolatile POA compared to the simulations with different gas-phase mechanisms. Compared to the simulation with CB05 and the default SOA module, the simulations with the VBS treatment improve cloud droplet number concentration (CDNC predictions (normalized mean biases from −40.8 % to a range of −34.6 to −27.7 %, with large differences between CB05–CB6 and SAPRC07 due to large differences in their OH and HO2 predictions. An advanced aerosol activation

Global impacts of tropospheric halogens (Cl, Br, I on oxidants and composition in GEOS-Chem

Directory of Open Access Journals (Sweden)

T. Sherwen

2016-09-01

Full Text Available We present a simulation of the global present-day composition of the troposphere which includes the chemistry of halogens (Cl, Br, I. Building on previous work within the GEOS-Chem model we include emissions of inorganic iodine from the oceans, anthropogenic and biogenic sources of halogenated gases, gas phase chemistry, and a parameterised approach to heterogeneous halogen chemistry. Consistent with Schmidt et al. (2016 we do not include sea-salt debromination. Observations of halogen radicals (BrO, IO are sparse but the model has some skill in reproducing these. Modelled IO shows both high and low biases when compared to different datasets, but BrO concentrations appear to be modelled low. Comparisons to the very sparse observations dataset of reactive Cl species suggest the model represents a lower limit of the impacts of these species, likely due to underestimates in emissions and therefore burdens. Inclusion of Cl, Br, and I results in a general improvement in simulation of ozone (O3 concentrations, except in polar regions where the model now underestimates O3 concentrations. Halogen chemistry reduces the global tropospheric O3 burden by 18.6 %, with the O3 lifetime reducing from 26 to 22 days. Global mean OH concentrations of 1.28  ×  106 molecules cm−3 are 8.2 % lower than in a simulation without halogens, leading to an increase in the CH4 lifetime (10.8 % due to OH oxidation from 7.47 to 8.28 years. Oxidation of CH4 by Cl is small (∼  2 % but Cl oxidation of other VOCs (ethane, acetone, and propane can be significant (∼  15–27 %. Oxidation of VOCs by Br is smaller, representing 3.9 % of the loss of acetaldehyde and 0.9 % of the loss of formaldehyde.

Electrophilic properties of patulin. Adduct structures and reaction pathways with 4-bromothiophenol and other model nucleophiles.

Science.gov (United States)

Fliege, R; Metzler, M

2000-05-01

The mycotoxin patulin (PAT) is believed to exert its cytotoxic and chromosome-damaging effects by forming covalent adducts with essential cellular thiols. Since the chemical structures of such adducts are unknown to date, we have studied the reaction of PAT and its O-acetylated derivative with the monofunctional thiol model compound 4-bromothiophenol (BTP), which was chosen due to analytical advantages. By means of analytical and preparative high-performance liquid chromatography, 16 adducts of PAT and 3 adducts of acetyl-PAT were isolated and their chemical structures elucidated by (1)H and (13)C NMR, IR, and UV spectroscopy. Time course studies and analysis of daughter product formation from isolated intermediate adducts led to a detailed scheme for the reaction of PAT with BTP. The structures of adducts of PAT formed with other model nucleophiles, e. g., the aliphatic thiol 2-mercaptoethanol and the aromatic amine 4-bromoaniline, were also elucidated and found to corroborate the reaction scheme. In addition, one further reaction pathway was observed with 2-mercaptoethanol, which appears to be independent from those found for BTP. Our study with model nucleophiles provides insights into the electrophilic reactivity of PAT and proved to be useful for the structure elucidation of PAT adducts with biological nucleophiles of toxicological relevance, as will be reported by Fliege and Metzler [(2000) Chem. Res. Toxicol. 13, 373-381].

Ocorrência, aspectos toxicológicos, métodos analíticos e controle da patulina em alimentos Occurrence, toxicological aspects, analytical methods and control of patulin in food

Directory of Open Access Journals (Sweden)

Juliane Elisa Welke

2009-02-01

Full Text Available A patulina é uma micotoxina produzida por várias espécies de Penicillium, Aspergillus e Byssochlamys. Em experimentos com animais, ela demonstrou ter atividade mutagênica, carcinogênica e teratogênica. Tem sido freqüentemente encontrada em maçãs e derivados. A patulina é facilmente transferida da maçã para o suco durante o processamento devido a sua alta solubilidade em água. Essa micotoxina é muito estável ao aquecimento em meio ácido, como no suco de maçã. Assim, a presença de patulina em suco de maçã é um indicador da qualidade das maçãs utilizadas no processamento. Muitos métodos têm sido desenvolvidos para a determinação da patulina, principalmente baseados na extração líquido-líquido com acetato de etila e determinação por CLAE. É importante evidenciar a necessidade de legislação que regulamente limites dessa micotoxina em alimentos no Brasil. Esta revisão bibliográfica tem como objetivos descrever as principais características da patulina, a ocorrência, os aspectos toxicológicose os métodos desenvolvidos para sua detecção e controle durante os estágios da produção da maçã e suco.Patulin is a mycotoxin produced by several Penicillium, Aspergillus and Byssochlamys species. Patulin is a highly toxic compound which has shown to be mutagenic, carcinogenic and teratogenic in experiments with animals. It has often been found in apples and apple products. Patulin is easily transfered into apple juice during processing due to its high solubility in water. This mycotoxin is very stable to heat in acidic medium as in apple juice. Thus, patulin content of apple juice is an indicator of the quality of the apples used to juice production. Many methods have been developed for the patulin determination mainly based on liquid-liquid extraction with ethyl acetate and use of HPLC for detection. It is important to show the need of legislation that imposes patulin limits in foods in Brazil. The objectives of

Effect of chemically and biologically synthesized Ag nanoparticles on the algae growth inhibition

Science.gov (United States)

Anna, Mražiková; Oksana, Velgosová; Jana, Kavuličová

2017-12-01

Over the past few years green methods for preparation of silver nanoparticles has become necessary due to its friendly influence on ecosystem. In the present work antimicrobial properties of biologically synthesized silver nanoparticles (Bio-AgNPs) using green algae extract and chemically synthesized silver nanoparticles (Chem-AgNPs) using sodium citrate against algae Parachlorella kessleri is investigated. Both used Bio-AgNPs and Chem-AgNPs exhibit long-term stability as demonstrated by UV-vis spectroscopy measurements. The results revealed stronger toxic effects of Bio-AgNPs on agar plates what was confirmed clear inhibition zone around wells impregnated with Bio-AgNPs. On the other hand Bio-AgNPs were confirmed to be less toxic in aquatic environments for the growths of green algae P. kessleri comparing to Chem-AgNPs.

Effective spectral densities for system-environment dynamics at conical intersections: S{sub 2}-S{sub 1} conical intersection in pyrazine

Energy Technology Data Exchange (ETDEWEB)

Martinazzo, Rocco [Department of Physical Chemistry and Electrochemistry, University of Milan, Via Golgi 19, 20122 Milan (Italy); Hughes, Keith H. [School of Chemistry, Bangor University, Bangor, Gwynedd LL57 2UW (United Kingdom); Martelli, Fausto [Department of Physical Chemistry and Electrochemistry, University of Milan, Via Golgi 19, 20122 Milan (Italy); Departement de Chimie, Ecole Normale Superieure, 24 rue Lhomond, F-75231 Paris cedex 05 (France); Burghardt, Irene, E-mail: irene.burghardt@ens.fr [Departement de Chimie, Ecole Normale Superieure, 24 rue Lhomond, F-75231 Paris cedex 05 (France)

2010-11-25

Graphical abstract: The effect of high-dimensional environments on conical intersections can be described by hierarchies of approximate spectral densities, which translate to truncated effective-mode chains in the time domain. Abstract: A recently developed effective-mode representation is employed to characterize the influence of a multi-dimensional environment on the S{sub 2}-S{sub 1} conical intersection in pyrazine, taken as a paradigm case of high-dimensional dynamics at a conical intersection. We consider a simplified model by which four modes are strongly coupled to the electronic subsystem while a number of weakly coupled tuning modes, inducing energy gap fluctuations, are sampled from a spectral density. The latter is approximated by a series of simplified spectral densities which can be cast into a continued-fraction form, as previously demonstrated in Hughes et al. (K.H. Hughes, C.D. Christ, I. Burghardt, J. Chem. Phys. 131 (2009) 124108). In the time domain, the hierarchy of spectral densities translates to truncated effective-mode chains with a Markovian or quasi-Markovian (Rubin type) closure. A sequential deconvolution procedure is employed to generate this chain representation. The implications for the ultrafast dynamics and its representation in terms of reduced-dimensional models are discussed.

ODM2 (Observation Data Model): The EarthChem Use Case

Science.gov (United States)

Lehnert, Kerstin; Song, Lulin; Hsu, Leslie; Horsburgh, Jeffrey S.; Aufdenkampe, Anthony K.; Mayorga, Emilio; Tarboton, David; Zaslavsky, Ilya

2014-05-01

PetDB is an online data system that was created in the late 1990's to serve online a synthesis of published geochemical and petrological data of igneous and metamorphic rocks. PetDB has today reached a volume of 2.5 million analytical values for nearly 70,000 rock samples. PetDB's data model (Lehnert et al., G-Cubed 2000) was designed to store sample-based observational data generated by the analysis of rocks, together with a wide range of metadata documenting provenance of the samples, analytical procedures, data quality, and data source. Attempts to store additional types of geochemical data such as time-series data of seafloor hydrothermal springs and volcanic gases, depth-series data for marine sediments and soils, and mineral or mineral inclusion data revealed the limitations of the schema: the inability to properly record sample hierarchies (for example, a garnet that is included in a diamond that is included in a xenolith that is included in a kimberlite rock sample), inability to properly store time-series data, inability to accommodate classification schemes other than rock lithologies, deficiencies of identifying and documenting datasets that are not part of publications. In order to overcome these deficiencies, PetDB has been developing a new data schema using the ODM2 information model (ODM=Observation Data Model). The development of ODM2 is a collaborative project that leverages the experience of several existing information representations, including PetDB and EarthChem, and the CUAHSI HIS Observations Data Model (ODM), as well as the general specification for encoding observational data called Observations and Measurements (O&M) to develop a uniform information model that seamlessly manages spatially discrete, feature-based earth observations from environmental samples and sample fractions as well as in-situ sensors, and to test its initial implementation in a variety of user scenarios. The O&M model, adopted as an international standard by the Open

Over-the-road tests of nuclear materials package response to normal environments

International Nuclear Information System (INIS)

Gwinn, K.W.; Glass, R.E.; Edwards, K.R.

1991-12-01

In support of the development of American National Standards Institute standards for the transport of radioactive materials, Sandia has a program to characterize the normal transport environment. This program includes both analytical modeling of package and trailer responses, and over-the-road tests to measure those responses. This paper presents the results of a series of over-the-road tests performed using Chem-Nuclear equipment in the Barnwell, SC, area. The test events included a variety of road types such as rough concrete, shock events such as railroad grade crossings, and driver responses such as sharp turns. The response of the package and trailer to these events was measured with accelerometers at various locations to determine the inertial loads. Either load cells or strain gages were used to measure tiedown response. These accelerations and loads were measured on systems with flexible and ''rigid'' tiedowns. The results indicated that while significant accelerations occur on the trailer bed, these do not translate into equivalent loads in either the package or the tiedown system. This indicates that trailer-bed response should not be used in determining the load factor for fatigue calculations of the package components or in determining design loads for tiedowns

Anthropogenic and volcanic emission impacts on SO2 dynamics and acid rain profiles. Numerical study using WRF-Chem in a high-resolution modeling

Science.gov (United States)

Vela, A. V.; González, C. M.; Ynoue, R.; Rojas, N. Y.; Aristizábal, B. H.; Wahl, M.

2017-12-01

Eulerian 3-D chemistry transport models (CTM) have been widely used for the study of air quality in urban environments, becoming an essential tool for studying the impacts and dynamics of gases and aerosols on air quality. However, their use in Colombia is scarce, especially in medium-sized cities, which are experimenting a fast urban growth, increasing the risk associated with possible air pollution episodes. In the densely populated medium-sized Andean city of Manizales, Colombia - a city located on the western slopes of the central range of the Andes (urban population 368000; 2150 m.a.s.l), there is an influence of the active Nevado del Ruiz volcano, located 28 km to the southwest. This natural source emits daily gas and particle fluxes, which could influence the atmospheric chemistry of the city and neighboring towns. Hence, the zone presents a unique combination of anthropogenic and volcanic sulfur gas emissions, which affects SO2 dynamics in the urban area, influencing also in the formation of acid rain phenomenon in the city. Therefore, studies analyzing the relative contribution of anthropogenic and volcanic emission could contribute with a deep understanding about causes and dynamics of both acid rain phenomenon and ambient SO2 levels in Manizales. This work aimed to analyze the influence of anthropogenic (on-road vehicular and industrial point-sources) and volcanic sulfur emissions in SO2 atmospheric chemistry dynamics, evaluating its possible effects on acid rain profiles. Ambient SO2 levels and day-night rain samples were measured and used to analyze results obtained from the application of the fully-coupled on-line WRF-Chem model. Two high-resolution simulations were performed during two dry and wet one-week periods in 2015. Analysis of SO2 dispersion patterns and comparison with SO2 observations in the urban area were performed for three different scenarios in which natural and anthropogenic emissions were simulated separately. Results suggest that

Photochemistry and transport of tropospheric ozone and its precursors in urban and remote environments

Science.gov (United States)

Anderson, Daniel Craig

Tropospheric ozone (O3) adversely affects human health, reduces crop yields, and contributes to climate forcing. To limit these effects, the processes controlling O3 abundance as well as that of its precursor molecules must be fully characterized. Here, I examine three facets of O 3 production, both in heavily polluted and remote environments. First, using in situ observations from the DISCOVER-AQ field campaign in the Baltimore/Washington region, I evaluate the emissions of the O 3 precursors CO and NOx (NOx = NO + NO2) in the National Emissions Inventory (NEI). I find that CO/NOx emissions ratios derived from observations are 21% higher than those predicted by the NEI. Comparisons to output from the CMAQ model suggest that CO in the NEI is accurate within 15 +/- 11%, while NOx emissions are overestimated by 51-70%, likely due to errors in mobile sources. These results imply that ambient ozone concentrations will respond more efficiently to NOx controls than current models suggest. I then investigate the source of high O3 and low H2O structures in the Tropical Western Pacific (TWP). A combination of in situ observations, satellite data, and models show that the high O3 results from photochemical production in biomass burning plumes from fires in tropical Southeast Asia and Central Africa; the low relative humidity results from large-scale descent in the tropics. Because these structures have frequently been attributed to mid-latitude pollution, biomass burning in the tropics likely contributes more to the radiative forcing of climate than previously believed. Finally, I evaluate the processes controlling formaldehyde (HCHO) in the TWP. Convective transport of near surface HCHO leads to a 33% increase in upper tropospheric HCHO mixing ratios; convection also likely increases upper tropospheric CH 3OOH to ~230 pptv, enough to maintain background HCHO at ~75 pptv. The long-range transport of polluted air, with NO four times the convectively controlled background

ChemView

Data.gov (United States)

U.S. Environmental Protection Agency — Search tool developed to provide stakeholders access to various TSCA chemicals, and health and safety information. The tool also provides EPA assessments and actions...

Amenazas toxicológicas del plástico

Science.gov (United States)

El plástico representa el 80 de la basura marina que se origina de desperdicios terrestres. La presencia de estos desechos pásticos tiene un impacto negativo en el medioambiente, el turismo, la industria de la pesca y la navegación.

Evaluating the effects of herbicide drift on nontarget terrestrial plants: A case study with mesotrione.

Science.gov (United States)

Brain, Richard A; Perine, Jeff; Cooke, Catriona; Ellis, Clare Butler; Harrington, Paul; Lane, Andrew; O'Sullivan, Christine; Ledson, Mark

2017-09-01

Nature of exposure is a fundamental driver in nontarget terrestrial plant risk assessment for pesticides; consequently a novel study was designed to generate field-based drift exposure and evaluate corresponding biological effects of the herbicide mesotrione. The approach used a combination of US guideline drift reduction technology and vegetative vigor approaches. In each of 3 independent replicate spray application trials, 10 pots each of lettuce and tomato were placed at distances of 10, 20, 30, 40, and 50 ft (∼3, 6, 9, 12, and 15 m) from the downwind edge of the spray boom. Each application was conducted using a commercial 60-ft (18-m) boom sprayer fitted with TeeJet ® Technologies TTI110025 nozzles, with a nominal application rate of 0.2 lb a.i./A (224 g a.i./ha). The environmental conditions required by the protocol (air temperature 10-30 °C and wind perpendicular to the swath (±30°) blowing toward the plants at a mean wind speed of ≥10 mph [≥4.5 m/s] measured at 2.0 m above the ground) were met for each application. Following exposure, plants were transferred to a greenhouse for the 21-d vegetative vigor phase of the study. Symptoms of phytotoxicity and plant height were assessed at 7, 14, and 21 d after treatment. On completion of the 21-d after treatment assessment, all plants were harvested and dried in an oven to determine shoot dry weight. The biological data indicated that no statistically significant effects were observed at a distance of 30 ft (∼9 m) from mesotrione drift at wind speeds of ≥10 mph (10.9-12.4 mph); this endpoint (30 ft) is defined as the no observed effects distance (NOED). Environ Toxicol Chem 2017;36:2465-2475. © 2017 SETAC. © 2017 SETAC.

Environmental risk assessment of engineered nano-SiO2 , nano iron oxides, nano-CeO2 , nano-Al2 O3 , and quantum dots.

Science.gov (United States)

Wang, Yan; Nowack, Bernd

2018-05-01

Many research studies have endeavored to investigate the ecotoxicological hazards of engineered nanomaterials (ENMs). However, little is known regarding the actual environmental risks of ENMs, combining both hazard and exposure data. The aim of the present study was to quantify the environmental risks for nano-Al 2 O 3 , nano-SiO 2 , nano iron oxides, nano-CeO 2 , and quantum dots by comparing the predicted environmental concentrations (PECs) with the predicted-no-effect concentrations (PNECs). The PEC values of these 5 ENMs in freshwaters in 2020 for northern Europe and southeastern Europe were taken from a published dynamic probabilistic material flow analysis model. The PNEC values were calculated using probabilistic species sensitivity distribution (SSD). The order of the PNEC values was quantum dots nano-CeO 2  nano iron oxides nano-Al 2 O 3  nano-SiO 2 . The risks posed by these 5 ENMs were demonstrated to be in the reverse order: nano-Al 2 O 3  > nano-SiO 2  > nano iron oxides > nano-CeO 2  > quantum dots. However, all risk characterization values are 4 to 8 orders of magnitude lower than 1, and no risk was therefore predicted for any of the investigated ENMs at the estimated release level in 2020. Compared to static models, the dynamic material flow model allowed us to use PEC values based on a more complex parameterization, considering a dynamic input over time and time-dependent release of ENMs. The probabilistic SSD approach makes it possible to include all available data to estimate hazards of ENMs by considering the whole range of variability between studies and material types. The risk-assessment approach is therefore able to handle the uncertainty and variability associated with the collected data. The results of the present study provide a scientific foundation for risk-based regulatory decisions of the investigated ENMs. Environ Toxicol Chem 2018;37:1387-1395. © 2018 SETAC. © 2018 SETAC.

Toxicity of sulfide to early life stages of wild rice (Zizania palustris).

Science.gov (United States)

Fort, Douglas J; Todhunter, Kevin; Fort, Troy D; Mathis, Michael B; Walker, Rachel; Hansel, Mike; Hall, Scott; Richards, Robin; Anderson, Kurt

2017-08-01

The sensitivity of wild rice (Zizania palustris) to sulfide is not well understood. Because sulfate in surface waters is reduced to sulfide by anaerobic bacteria in sediments and historical information indicated that 10 mg/L sulfate in Minnesota (USA) surface water reduced Z. palustris abundance, the Minnesota Pollution Control Agency established 10 mg/L sulfate as a water quality criterion in 1973. A 21-d daily-renewal hydroponic study was conducted to evaluate sulfide toxicity to wild rice and the potential mitigation of sulfide toxicity by iron (Fe). The hydroponic design used hypoxic test media for seed and root exposure and aerobic headspace for the vegetative portion of the plant. Test concentrations were 0.3, 1.6, 3.1, 7.8, and 12.5 mg/L sulfide in test media with 0.8, 2.8, and 10.8 mg/L total Fe used to evaluate the impact of iron on sulfide toxicity. Visual assessments (i.e., no plants harvested) of seed activation, mesocotyl emergence, seedling survival, and phytoxicity were conducted 10 d after dark-phase exposure. Each treatment was also evaluated for time to 30% emergence (ET30), total plant biomass, root and shoot lengths, and signs of phytotoxicity at study conclusion (21 d). The results indicate that exposure of developing wild rice to sulfide at ≥3.1 mg sulfide/L in the presence of 0.8 mg/L Fe reduced mesocotyl emergence. Sulfide toxicity was mitigated by the addition of Fe at 2.8 mg/L and 10.8 mg/L relative to the control value of 0.8 mg Fe/L, demonstrating the importance of iron in mitigating sulfide toxicity to wild rice. Ultimately, determination of site-specific sulfate criteria taking into account factors that alter toxicity, including sediment Fe and organic carbon, are necessary. Environ Toxicol Chem 2017;36:2217-2226. © 2017 SETAC. © 2017 SETAC.

Toxicity of sediment-associated substituted phenylamine antioxidants on the early life stages of Pimephales promelas and a characterization of effects on freshwater organisms.

Science.gov (United States)

Prosser, Ryan S; Parrott, Joanne L; Galicia, Melissa; Shires, Kallie; Sullivan, Cheryl; Toito, John; Bartlett, Adrienne J; Milani, Danielle; Gillis, Patty L; Balakrishnan, Vimal K

2017-10-01

Substituted phenylamine antioxidants (SPAs) are high production volume chemicals that are incorporated into a variety of commercial products (e.g., polymers, dyes, lubricants). There are few data on chronic toxicity of SPAs to fish and no data on the toxicity of SPAs to the early life stages of fish. The physicochemical properties of SPAs would suggest that if they were to enter an aquatic ecosystem they would partition into sediment. Therefore, the present study focused on investigating the chronic effect of sediment-associated SPAs to the early life stages of the fathead minnow (Pimephales promelas). Eggs and larvae were exposed to sediment spiked with diphenylamine (DPA), N-phenyl-1-napthylamine (PNA), N-(1,3-dimethylbutyl)-N'-phenyl-1,4-phenylenediamine (DPPDA), or 4,4'-methylene-bis[N-sec-butylaniline] (MBA). The most sensitive endpoint for DPA, PNA, and DPPDA was total survival with 21-d median lethal concentrations (LC50s) based on concentration in overlying water of 1920, 74, and 35 μg/L, respectively. The most sensitive endpoint for MBA was growth with a 21-d median effective concentration (EC50) of 71 μg/L. The same endpoints were the most sensitive in terms of concentrations of DPA, PNA, DPPDA, and MBA in sediment (101, 54, 111, and 76 μg/g dry wt, respectively). Species sensitivity distributions (SSDs) were constructed for each SPA based on acute and chronic toxicity data generated in the present study and found in the literature. Overall, P. promelas was in the midrange of chronic sensitivity, with the most sensitive species being Tubifex tubifex. The SSDs indicate that DPA based on concentration in water is the least toxic to aquatic biota of the 4 SPAs investigated. The constructed SSDs indicate that a concentration in water and sediment of 1 μg/L and 1 μg/g dry weight, respectively, would be protective of >95% of the aquatic species tested. Environ Toxicol Chem 2017;36:2730-2738. © 2017 SETAC. © 2017 SETAC.

Comprehensive characterization of the acute and chronic toxicity of the neonicotinoid insecticide thiamethoxam to a suite of aquatic primary producers, invertebrates, and fish.

Science.gov (United States)

Finnegan, Meaghean C; Baxter, Leilan R; Maul, Jonathan D; Hanson, Mark L; Hoekstra, Paul F

2017-10-01

Thiamethoxam is a neonicotinoid insecticide used widely in agriculture to control a broad spectrum of chewing and sucking insect pests. Recent detection of thiamethoxam in surface waters has raised interest in characterizing the potential impacts of this insecticide to aquatic organisms. We report the results of toxicity testing (acute and chronic) conducted under good laboratory practices for more than 30 freshwater species (insects, molluscs, crustaceans, algae, macrophytes, and fish) and 4 marine species (an alga, a mollusc, a crustacean, and a fish). As would be anticipated for a neonicotinoid, aquatic primary producers and fish were the least sensitive organisms tested, with acute median lethal and effect concentrations (LC50/EC50) observed to be ≥80 mg/L in all cases, which far exceeds surface water exposure concentrations. Tested molluscs, worms, and rotifers were similarly insensitive (EC50 ≥ 100 mg/L), except for Lumbriculus sp., with an EC50 of 7.7 mg/L. In general, insects were the most sensitive group in the study, with most acute EC50 values insects (acute EC50 insects (EC50 > 5.5 mg/L). The most sensitive chronic response was for Chironomus riparius, with a 30-d no-observed-effect concentration (NOEC; emergence) of 0.01 mg/L. Observed toxicity to the tested marine organisms was comparable to that of freshwater species. We used the reported data to construct species sensitivity distributions for thiamethoxam, to calculate 5% hazard concentrations (HC5s) for acute data (freshwater invertebrates), and compared these with measured concentrations from relevant North American surface waters. Overall, based on acute toxicity endpoints, the potential acute risk to freshwater organisms was found to be minimal (likelihood of exceeding HC5s < 1%). Environ Toxicol Chem 2017;36:2838-2848. © 2017 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC. © 2017 The Authors. Environmental

Larval aquatic insect responses to cadmium and zinc in experimental streams.

Science.gov (United States)

Mebane, Christopher A; Schmidt, Travis S; Balistrieri, Laurie S

2017-03-01

To evaluate the risks of metal mixture effects to natural stream communities under ecologically relevant conditions, the authors conducted 30-d tests with benthic macroinvertebrates exposed to cadmium (Cd) and zinc (Zn) in experimental streams. The simultaneous exposures were with Cd and Zn singly and with Cd+Zn mixtures at environmentally relevant ratios. The tests produced concentration-response patterns that for individual taxa were interpreted in the same manner as classic single-species toxicity tests and for community metrics such as taxa richness and mayfly (Ephemeroptera) abundance were interpreted in the same manner as with stream survey data. Effect concentrations from the experimental stream exposures were usually 2 to 3 orders of magnitude lower than those from classic single-species tests. Relative to a response addition model, which assumes that the joint toxicity of the mixtures can be predicted from the product of their responses to individual toxicants, the Cd+Zn mixtures generally showed slightly less than additive toxicity. The authors applied a modeling approach called Tox to explore the mixture toxicity results and to relate the experimental stream results to field data. The approach predicts the accumulation of toxicants (hydrogen, Cd, and Zn) on organisms using a 2-pK a bidentate model that defines interactions between dissolved cations and biological receptors (biotic ligands) and relates that accumulation through a logistic equation to biological response. The Tox modeling was able to predict Cd+Zn mixture responses from the single-metal exposures as well as responses from field data. The similarity of response patterns between the 30-d experimental stream tests and field data supports the environmental relevance of testing aquatic insects in experimental streams. Environ Toxicol Chem 2017;36:749-762. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the

Improving substance information in USEtox® , part 1: Discussion on data and approaches for estimating freshwater ecotoxicity effect factors.

Science.gov (United States)

Saouter, Erwan; Aschberger, Karin; Fantke, Peter; Hauschild, Michael Z; Bopp, Stephanie K; Kienzler, Aude; Paini, Alicia; Pant, Rana; Secchi, Michela; Sala, Serenella

2017-12-01

The scientific consensus model USEtox ® is recommended by the European Commission as the reference model to characterize life cycle chemical emissions in terms of their potential human toxicity and freshwater aquatic ecotoxicity impacts in the context of the International Reference Life Cycle Data System Handbook and the Environmental Footprint pilot phase looking at products (PEF) and organizations (OEF). Consequently, this model has been systematically used within the PEF/OEF pilot phase by 25 European Union industry sectors, which manufacture a wide variety of consumer products. This testing phase has raised some questions regarding the derivation of and the data used for the chemical-specific freshwater ecotoxicity effect factor in USEtox. For calculating the potential freshwater aquatic ecotoxicity impacts, USEtox bases the effect factor on the chronic hazard concentration (HC50) value for a chemical calculated as the arithmetic mean of all logarithmized geometric means of species-specific chronic median lethal (or effect) concentrations (L[E]C50). We investigated the dependency of the USEtox effect factor on the selection of ecotoxicological data source and toxicological endpoints, and we found that both influence the ecotoxicity ranking of chemicals and may hence influence the conclusions of a PEF/OEF study. We furthermore compared the average measure (HC50) with other types of ecotoxicity effect indicators, such as the lowest species EC50 or no-observable-effect concentration, frequently used in regulatory risk assessment, and demonstrated how they may also influence the ecotoxicity ranking of chemicals. We acknowledge that these indicators represent different aspects of a chemical's ecotoxicity potential and discuss their pros and cons for a comparative chemical assessment as performed in life cycle assessment and in particular within the PEF/OEF context. Environ Toxicol Chem 2017;36:3450-3462. © 2017 The Authors. Environmental Toxicology and Chemistry

Comparative chronic toxicity of imidacloprid, clothianidin, and thiamethoxam to Chironomus dilutus and estimation of toxic equivalency factors.

Science.gov (United States)

Cavallaro, Michael C; Morrissey, Christy A; Headley, John V; Peru, Kerry M; Liber, Karsten

2017-02-01

clothianidin, thereby likely enhancing toxicity. Environ Toxicol Chem 2017;36:372-382. © 2016 SETAC. © 2016 SETAC.

Riparian spiders as sentinels of polychlorinated biphenyl contamination across heterogeneous aquatic ecosystems.

Science.gov (United States)

Kraus, Johanna M; Gibson, Polly P; Walters, David M; Mills, Marc A

2017-05-01

Riparian spiders are being used increasingly to track spatial patterns of contaminants in and fluxing from aquatic ecosystems. However, our understanding of the circumstances under which spiders are effective sentinels of aquatic pollution is limited. The present study tests the hypothesis that riparian spiders may be effectively used to track spatial patterns of sediment pollution by polychlorinated biphenyls (PCBs) in aquatic ecosystems with high habitat heterogeneity. The spatial pattern of ΣPCB concentrations in 2 common families of riparian spiders sampled in 2011 to 2013 generally tracked spatial variation in sediment ΣPCBs across all sites within the Manistique River Great Lakes Area of Concern (AOC), a rivermouth ecosystem located on the south shore of the Upper Peninsula, Manistique (MI, USA) that includes harbor, river, backwater, and lake habitats. Sediment ΣPCB concentrations normalized for total organic carbon explained 41% of the variation in lipid-normalized spider ΣPCB concentrations across 11 sites. Furthermore, 2 common riparian spider taxa (Araneidae and Tetragnathidae) were highly correlated (r 2  > 0.78) and had similar mean ΣPCB concentrations when averaged across all years. The results indicate that riparian spiders may be useful sentinels of relative PCB availability to aquatic and riparian food webs in heterogeneous aquatic ecosystems like rivermouths where habitat and contaminant variability may make the use of aquatic taxa less effective. Furthermore, the present approach appears robust to heterogeneity in shoreline development and riparian vegetation that support different families of large web-building spiders. Environ Toxicol Chem 2017;36:1278-1286. Published 2016 Wiley Periodicals, Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2016 Wiley Periodicals, Inc. on behalf of SETAC. This article is a US government work and, as such, is in

gis-based hydrological model based hydrological model upstream

African Journals Online (AJOL)

eobe

(GIS) environment to simulate various parame attributed to a ... water, sediment and agricultural chem large complex .... The 90m resolution topography data (see Figure 2) used for this .... results of the calibration and validation exercise are as.

Radiative effects of light-absorbing particles deposited in snow over Himalayas using WRF-Chem simulations

Science.gov (United States)

Sarangi, C.; Qian, Y.; Painter, T. H.; Liu, Y.; Lin, G.; Wang, H.

2017-12-01

Radiative forcing induced by light-absorbing particles (LAP) deposited on snow is an important surface forcing. It has been debated that an aerosol-induced increase in atmospheric and surface warming over Tibetan Plateau (TP) prior to the South Asian summer monsoon can have a significant effect on the regional thermodynamics and South Asian monsoon circulation. However, knowledge about the radiative effects due to deposition of LAP in snow over TP is limited. In this study we have used a high-resolution WRF-Chem (coupled with online chemistry and snow-LAP-radiation model) simulations during 2013-2014 to estimate the spatio-temporal variation in LAP deposition on snow, specifically black carbon (BC) and dust particles, in Himalayas. Simulated distributions in meteorology, aerosol concentrations, snow albedo, snow grain size and snow depth are evaluated against satellite and in-situ measurements. The spatio-temporal change in snow albedo and snow grain size with variation in LAP deposition is investigated and the resulting shortwave LAP radiative forcing at surface is calculated. The LAP-radiative forcing due to aerosol deposition, both BC and dust, is higher in magnitude over Himalayan slopes (terrain height below 4 km) compared to that over TP (terrain height above 4 km). We found that the shortwave aerosol radiative forcing efficiency at surface due to increase in deposited mass of BC particles in snow layer ( 25 (W/m2)/ (mg/m2)) is manifold higher than the efficiency of dust particles ( 0.1 (W/m2)/ (mg/m2)) over TP. However, the radiative forcing of dust deposited in snow is similar in magnitude (maximum 20-30 W/m2) to that of BC deposited in snow over TP. This is mainly because the amount of dust deposited in snow over TP can be about 100 times greater than the amount of BC deposited in snow during polluted conditions. The impact of LAP on surface energy balance, snow melting and atmospheric thermodynamics is also examined.

Avaliação toxicológica e reprodutiva de camundongos machos adultos tratados com femproporex - DOI: 10.4025/actascihealthsci.1089 Fenproporex treatment in male mice: behavior and toxicology reproductive analysis - DOI: 10.4025/actascihealthsci.1089

Directory of Open Access Journals (Sweden)

Estefânia Gastaldello Moreira

2008-03-01

Full Text Available O femproporex é utilizado no mundo todo como potente anorexígeno. Este estudo visa esclarecer se o uso diário de femproporex provoca toxicidade comportamental e/ou reprodutiva em camundongos machos adultos. Para tanto, foram utilizados 40 camundongos, divididos em quatro grupos experimentais, cada um contendo dez animais. Um dos grupos recebeu, via gavage, apenas água, e os outros foram tratados diariamente com femproporex, nas doses de 7,5, 15 e 30 mg kg-1, por um período de 40 dias. Como resultados, verificou-se que o femproporex não alterou a evolução normal da massa dos animais analisados, e concluiu-se que a utilização da droga não promoveu toxicidade comportamental, verificada nos testes de natação forçada e de campo aberto; e reprodutiva, quando verificados genotoxicidade, síntese de testosterona, morfologia de espermatozóides e histologia testicular. Assim sendo, concluiu-se que o femproporex, na concentração e delineamentos experimentais propostos por este trabalho, não apresentou potencial toxicológicoFenproporex is used worldwide as a powerful anorectic drug. This study was designed to evaluate whether daily intake of fenproporex would lead to behavioral and/or reproductive toxicity in adult male mice. Fourty male mice were used, divided into 4 groups of 10 animals each. The control group received only water by gavage, whereas the experimental groups were treated daily with fenproporex in the doses of 7.5, 15 and 30 mg kg-1, for a period of 40 days. The results demonstrated that fenproporex did not alter the normal evolution of the animals’ body mass; it also showed that the use of the drug did not promote behavioral toxicity (open-field and forced-swimming tests or reproductive toxicity (genotoxicity, changes in the morphology of spermatozoa and testicular histology. Thus, the present results indicate that fenproporex, in the evaluated dose and experimental conditions, does not present behavioral and

Qualification of Fiber Optic Cables for Martian Extreme Temperature Environments

Science.gov (United States)

Ramesham, Rajeshuni; Lindensmith, Christian A.; Roberts, William T.; Rainen, Richard A.

2011-01-01

Means have been developed for enabling fiber optic cables of the Laser Induced Breakdown Spectrometer instrument to survive ground operations plus the nominal 670 Martian conditions that include Martian summer and winter seasons. The purpose of this development was to validate the use of the rover external fiber optic cabling of ChemCam for space applications under the extreme thermal environments to be encountered during the Mars Science Laboratory (MSL) mission. Flight-representative fiber optic cables were subjected to extreme temperature thermal cycling of the same diurnal depth (or delta T) as expected in flight, but for three times the expected number of in-flight thermal cycles. The survivability of fiber optic cables was tested for 600 cumulative thermal cycles from -130 to +15 C to cover the winter season, and another 1,410 cumulative cycles from -105 to +40 C to cover the summer season. This test satisfies the required 3 times the design margin that is a total of 2,010 thermal cycles (670 x 3). This development test included functional optical transmission tests during the course of the test. Transmission of the fiber optic cables was performed prior to and after 1,288 thermal cycles and 2,010 thermal cycles. No significant changes in transmission were observed on either of the two representative fiber cables subject through the 3X MSL mission life that is 2,010 thermal cycles.

Application of a coupled ecosystem-chemical equilibrium model, DayCent-Chem, to stream and soil chemistry in a Rocky Mountain watershed

Science.gov (United States)

Hartman, M.D.; Baron, Jill S.; Ojima, D.S.

2007-01-01

Atmospheric deposition of sulfur and nitrogen species have the potential to acidify terrestrial and aquatic ecosystems, but nitrate and ammonium are also critical nutrients for plant and microbial productivity. Both the ecological response and the hydrochemical response to atmospheric deposition are of interest to regulatory and land management agencies. We developed a non-spatial biogeochemical model to simulate soil and surface water chemistry by linking the daily version of the CENTURY ecosystem model (DayCent) with a low temperature aqueous geochemical model, PHREEQC. The coupled model, DayCent-Chem, simulates the daily dynamics of plant production, soil organic matter, cation exchange, mineral weathering, elution, stream discharge, and solute concentrations in soil water and stream flow. By aerially weighting the contributions of separate bedrock/talus and tundra simulations, the model was able to replicate the measured seasonal and annual stream chemistry for most solutes for Andrews Creek in Loch Vale watershed, Rocky Mountain National Park. Simulated soil chemistry, net primary production, live biomass, and soil organic matter for forest and tundra matched well with measurements. This model is appropriate for accurately describing ecosystem and surface water chemical response to atmospheric deposition and climate change. ?? 2006 Elsevier B.V. All rights reserved.

Simulating SAL formation and aerosol size distribution during SAMUM-I

KAUST Repository

Khan, Basit Ali; Stenchikov, Georgiy L.; Weinzierl,  Bernadett; Kalenderski, Stoitchko; Osipov, Sergey

2015-01-01

-Chem) to reproduce the meteorological environment and spatial and size distributions of dust. The experimental domain covers northwest Africa including the southern Sahara, Morocco and part of the Atlantic Ocean with 5 km horizontal grid spacing and 51 vertical

Does monosodium glutamate really cause headache? : a systematic review of human studies.

Science.gov (United States)

Obayashi, Yoko; Nagamura, Yoichi

2016-01-01

Although monosodium glutamate (MSG) is classified as a causative substance of headache in the International Classification of Headache Disorders 3rd edition (ICHD-III beta), there is no literature in which causal relationship between MSG and headache was comprehensively reviewed. We performed systematic review of human studies which include the incidence of headache after an oral administration of MSG. An analysis was made by separating the human studies with MSG administration with or without food, because of the significant difference of kinetics of glutamate between those conditions (Am J Clin Nutr 37:194-200, 1983; J Nutr 130:1002S-1004S, 2000) and there are some papers which report the difference of the manifestation of symptoms after MSG ingestion with or without food (Food Chem Toxicol 31:1019-1035, 1993; J Nutr 125:2891S-2906S, 1995). Of five papers including six studies with food, none showed a significant difference in the incidence of headache except for the female group in one study. Of five papers including seven studies without food, four studies showed a significant difference. Many of the studies involved administration of MSG in solution at high concentrations (>2 %). Since the distinctive MSG is readily identified at such concentrations, these studies were thought not to be properly blinded. Because of the absence of proper blinding, and the inconsistency of the findings, we conclude that further studies are required to evaluate whether or not a causal relationship exists between MSG ingestion and headache.

Solvothermal synthesis and theoretical study of a polypyridium ...

Indian Academy of Sciences (India)

life sciences, clinical medicine, and material chem- istry.11–14 Many .... environment and charge balance, the H3BTC should be fully deprotonated, but the ..... ous work, we now attempt to combine rare earth metal ions with adduct 1 to ...

Simulated effect of timing and Pt quantity injected on On-line NobleChem application on total fuel liftoff

International Nuclear Information System (INIS)

Pop, M.G.; Riddle, J.M.; Lamanna, L.S.; Gregorich, C.; Hoornik, A.

2015-01-01

Total liftoff is a measure of fuel performance and a risk indicator for fuel reliability. Fuel operability and license limits are directly related to the expected total lifetime liftoff. AREVA's continued commitment to zero fuel failure is expressed, among other efforts, in the continued development and improvement of its fuel cladding corrosion and crud risk assessment tools. The AREVA models used to assess and predict crud deposition on BWR cores over their lifespan have been refined by the development and incorporation of the PEZOG tool in response to the move in the industry to the On-Line NobleChem TM (OLNC) technology. PEZOG models the platinum-enhanced zirconium oxide growth of fuel cladding when exposed to platinum during operation. Depending on the local chemistry and radiation condition, noble metals act as catalysts for many reactions, including but not limited to hydrogen oxidation and oxygen reduction. OLNC's intention is to catalyze the hydrogen and oxygen recombination reaction for core internals protection. However, research has indicated that noble metals catalyze the oxygen reduction under the chemistry and radiation conditions as experienced in the pores of crud deposits, and hence, can increase the corrosion rate of zirconium alloy cladding. The developed PEZOG module calculates the oxide thickness as a function of platinum injection strategy. The stratified nature of oxide and crud layers formed on fuel cladding surfaces is reflected in the calculations as are the different platinum interaction in each of the layers. This paper presents examples of the evaluation of various aspects of the platinum injection strategies and their influence on the oxide growth enhancement as applied to conditions of a U.S. plant. (authors)

Contributions of mobile, stationary and biogenic sources to air pollution in the Amazon rainforest: a numerical study with the WRF-Chem model

Science.gov (United States)

Abou Rafee, Sameh A.; Martins, Leila D.; Kawashima, Ana B.; Almeida, Daniela S.; Morais, Marcos V. B.; Souza, Rita V. A.; Oliveira, Maria B. L.; Souza, Rodrigo A. F.; Medeiros, Adan S. S.; Urbina, Viviana; Freitas, Edmilson D.; Martin, Scot T.; Martins, Jorge A.

2017-06-01

This paper evaluates the contributions of the emissions from mobile, stationary and biogenic sources on air pollution in the Amazon rainforest by using the Weather Research and Forecasting with Chemistry (WRF-Chem) model. The analyzed air pollutants were CO, NOx, SO2, O3, PM2. 5, PM10 and volatile organic compounds (VOCs). Five scenarios were defined in order to evaluate the emissions by biogenic, mobile and stationary sources, as well as a future scenario to assess the potential air quality impact of doubled anthropogenic emissions. The stationary sources explain the highest concentrations for all air pollutants evaluated, except for CO, for which the mobile sources are predominant. The anthropogenic sources considered resulted an increasing in the spatial peak-temporal average concentrations of pollutants in 3 to 2780 times in relation to those with only biogenic sources. The future scenario showed an increase in the range of 3 to 62 % in average concentrations and 45 to 109 % in peak concentrations depending on the pollutant. In addition, the spatial distributions of the scenarios has shown that the air pollution plume from the city of Manaus is predominantly transported west and southwest, and it can reach hundreds of kilometers in length.

Contributions of mobile, stationary and biogenic sources to air pollution in the Amazon rainforest: a numerical study with the WRF-Chem model

Directory of Open Access Journals (Sweden)

S. A. Abou Rafee

2017-06-01

Full Text Available This paper evaluates the contributions of the emissions from mobile, stationary and biogenic sources on air pollution in the Amazon rainforest by using the Weather Research and Forecasting with Chemistry (WRF-Chem model. The analyzed air pollutants were CO, NOx, SO2, O3, PM2. 5, PM10 and volatile organic compounds (VOCs. Five scenarios were defined in order to evaluate the emissions by biogenic, mobile and stationary sources, as well as a future scenario to assess the potential air quality impact of doubled anthropogenic emissions. The stationary sources explain the highest concentrations for all air pollutants evaluated, except for CO, for which the mobile sources are predominant. The anthropogenic sources considered resulted an increasing in the spatial peak-temporal average concentrations of pollutants in 3 to 2780 times in relation to those with only biogenic sources. The future scenario showed an increase in the range of 3 to 62 % in average concentrations and 45 to 109 % in peak concentrations depending on the pollutant. In addition, the spatial distributions of the scenarios has shown that the air pollution plume from the city of Manaus is predominantly transported west and southwest, and it can reach hundreds of kilometers in length.

In vivo identical reversibility of rad-bio-chem lesions in blood, bone marrow, liver, endocrine system and on the whole body

International Nuclear Information System (INIS)

Stan, C.

2009-01-01

The fundamental scientific researches of a new patented pharmaceutical product STANOSIMAGNE, was initiated, directed and developed since 1995, as interdisciplinary challenge for in vivo decorporation on natural way of radio-toxic uranium (235U) and radionuclides, and the treatment of lesions induced by radiation injury, or heavy metals. The synergic effect - decorporation and reversibility - for in vivo identical reversibility of rad-bio-chem lesions in blood, bone marrow, liver, endocrine system, derma and vital organs verifies and sustains the scientific discovery. The safety and efficiency of clinical administration of the medicine STANOSIMAGNE capsules and ointment is based on the non-clinic (pre-clinic) practical pharmacological research on 635 standard laboratory animals regarding the absence of any kind of toxicity. The pharmacology researches have been carried out, along with medical, pharmaceutical and biochemical didactic specialists, coming from the Laboratories Departments of Pharmacology, Phytochemistry, Biochemistry, Chemistry and Pharmaceutical Technique of the University of Medicine and Pharmacy 'Carol Davila', Bucharest. The treatment of the persons exposed to irradiation or heavy metals contamination, in risk areas, and the continuation of the pilot clinical studies on several cases, that could not be solved by regular medical methods and treatments, are in accordance with the Directive 2001/20/CE, of the Parliament of the European Union, which implement the norms of good practice, in clinical studies.(author)

What Is the Optimum Strain for Pt Alloys for Oxygen Electroreduction?

DEFF Research Database (Denmark)

Escribano, Maria Escudero; Malacrida, Paolo; Velazquez-Palenzuela, Amado Andres

2015-01-01

demonstrate that we can engineer both the activity and stability by tuning the Pt-Pt distance. References [1] I.E.L. Stephens, A.S. Bondarenko, U. Grønbjerg, J. Rossmeisl, I. Chorkendorff, Energy Environ. Sci. 2012, 5, 6744. [2] S. Chen, H.A. Gasteiger, K. Hayakawa, T. Tada, Y. Shao-Horn, J. Electrochem. Soc....... 2010, 1571, A82. [3] M. Escudero-Escribano, et al., J. Am. Chem. Soc. 2012, 130, 16476. [4] P. Malacrida, M. Escudero-Escribano, A. Verdaguer-Casadevall, I.E.L. Stephens, I. Chorkendorff, J. Mater. Chem. A 2014, 2, 4234. [5] M. Escudero-Escribano, et al., to be submitted, 2014. [6] P. Strasser, et al...

Implementation of the U.S. Environmental Protection Agency's Waste Reduction (WAR) Algorithm in Cape-Open Based Process Simulators

Science.gov (United States)

The Sustainable Technology Division has recently completed an implementation of the U.S. EPA's Waste Reduction (WAR) Algorithm that can be directly accessed from a Cape-Open compliant process modeling environment. The WAR Algorithm add-in can be used in AmsterChem's COFE (Cape-Op...

Evaluation of anaerobic soil disinfestation amendments and rates for conventional tomato production in Florida

Science.gov (United States)

Methyl bromide and other soil fumigants have been heavily relied upon to control soilborne plant pathogens, nematodes, and weeds in polyethylene-mulched vegetable production in Florida. However, negative aspects of their use on the environment and human health have increased the interest in non-chem...

Sensitivity of CAM-Chem/DART MOPITT CO Assimilation Performance to the Choice of Ensemble System Configuration: A Case Study for Fires in the Amazon

Science.gov (United States)

Arellano, A. F., Jr.; Tang, W.

2017-12-01

Assimilating observational data of chemical constituents into a modeling system is a powerful approach in assessing changes in atmospheric composition and estimating associated emissions. However, the results of such chemical data assimilation (DA) experiments are largely subject to various key factors such as: a) a priori information, b) error specification and representation, and c) structural biases in the modeling system. Here we investigate the sensitivity of an ensemble-based data assimilation state and emission estimates to these key factors. We focus on investigating the assimilation performance of the Community Earth System Model (CESM)/CAM-Chem with the Data Assimilation Research Testbed (DART) in representing biomass burning plumes in the Amazonia during the 2008 fire season. We conduct the following ensemble DA MOPITT CO experiments: 1) use of monthly-average NCAR's FINN surface fire emissionss, 2) use of daily FINN surface fire emissions, 3) use of daily FINN emissions with climatological injection heights, and 4) use of perturbed FINN emission parameters to represent not only the uncertainties in combustion activity but also in combustion efficiency. We show key diagnostics of assimilation performance for these experiments and verify with available ground-based and aircraft-based measurements.

induced by cadmium using random amplified polymorphic DNA

African Journals Online (AJOL)

darya

2013-04-17

Apr 17, 2013 ... metallurgy, painting, plastic production, etc., and is being released into the biosphere, and ...... aquatic macrophytes: Random amplified polymorphic DNA analysis and identification of ... ecotoxicology. Toxicol. Ecotoxicol.

Estudo preliminar toxicológico, antibacteriano e fitoquímico do extrato etanólico das folhas de Jatropha mollissima (Pohl Baill. (pinhão-bravo, Euphorbiaceae, coletada no Município de Tauá, Ceará, Nordeste Brasileiro

Directory of Open Access Journals (Sweden)

I.D. BRAQUEHAIS

Full Text Available RESUMO A cada dia, cepas bacterianas estão tornando-se resistentes a diversos antibióticos, o que faz necessária a busca de novas substâncias eficazes para o tratamento de doenças. Desta forma, este trabalho reporta o estudo preliminar toxicológico, antibacteriano e fitoquímico do extrato etanólico das folhas de Jatropha mollissima (pinhão-bravo, Euphorbiaceae, coletada no Município de Tauá, Ceará, Nordeste Brasileiro. Inicialmente, realizou-se o teste de toxicidade do extrato contra Artemia salina. Na sequencia, foi realizado o ensaio antibacteriano contra quatro cepas bacterianas Gram-negativas (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Hafnia alvei ATCC 51873, Klebsiella pneumoniae ATCC 13883 e uma cepa Gram-positiva (Enterococcus faecalis ATCC 29212. Finalmente, fez-se a análise fitoquímica preliminar do extrato ativo para detecção das principais classes de metabólitos especiais. Como resultado, o extrato etanólico das folhas de J. mollissima se mostrou tóxico para Artemia salina, pois apresentou CL50 igual a 406,02 μg/mL. Quanto à ação antibacteriana, o extrato se mostrou ativo contra a bactéria Gram-positiva Enterococcus faecalis ATCC 29212, apresentando moderada atividade antibacteriana (halo de inibição igual a 7,03 mm. Evidenciou-se no extrato bioativo a presença de cumarinas, fenóis, taninos, flavonoides (flavonóis e flavanonas, alcaloides e esteroides, ambas as classes reportadas como antimicrobianos. Portanto, esse extrato tem potencial para ser usado na produção de fármacos contra infecções causadas por bactérias Gram-positivas. No entanto, as informações direcionam estudos futuros para o isolamento e identificação dos compostos bioativos, monitorados sob a ação antibacteriana mais expressiva.

TREATMENT OF NONADIABATIC TRANSITIONS BY DENSITY-MATRIX EVOLUTION AND MOLECULAR-DYNAMICS SIMULATIONS

NARCIS (Netherlands)

MAVRI, J; BERENDSEN, HJC

1994-01-01

A density matrix evolution (DME) method (H.J.C. Berendsen and J. Mavri, J. Phys. Chem., 97 (1993) 13469) to simulate the dynamics of quantum systems embedded in a classical environment is presented. The DME method allows treatment of nonadiabatic transitions. As numerical examples the collinear

ChemDuino: Adapting Arduino for Low-Cost Chemical Measurements in Lecture and Laboratory

Science.gov (United States)

Kubínova´, S?te?pa´nka; S?le´gr, Jan

2015-01-01

In everyday praxis, we often need demonstration measuring devices (thermometers, pH meters, etc.), with large enough displays to be easily readable from every point in the classroom. Here, we present some of the capabilities of the Arduino platform for the school environment. This microprocessor board can be used for inexpensive construction of…

Estrogenic activity and estrogen receptor β binding of the UV filter 3-benzylidene camphor Comparison with 4-methylbenzylidene camphor

International Nuclear Information System (INIS)

Schlumpf, Margret; Jarry, Hubert; Wuttke, Wolfgang; Ma, Risheng; Lichtensteiger, Walter

2004-01-01

UV filters represent new classes of estrogenic [Environ. Health Perspect. 109 (2001) 239] or antiandrogenic [Toxicol. Sci. 74 (2003) 43] chemicals. We tested 3-benzylidene camphor (3-BC), reported as estrogenic in fish [Pharmacol. Toxicol. 91 (2002) 204], and mammalian systems in comparison to 4-methylbenzylidene camphor (4-MBC), shown to be active in rats, and analyzed binding to estrogen receptor subtypes. 3-BC and 4-MBC stimulated MCF-7 cell proliferation (EC 50 : 0.68 and 3.9 μM). The uterotrophic assay of 3-BC (oral gavage) in immature rats showed unexpected potency with ED50 45.3 mg/kg per day; lowest effective dose 2 mg/kg per day, and maximum effect with 70% of ethinylestradiol. After comparing with literature data, we found that the oral 3-BC was considerably more potent than oral bisphenol A and almost as active as subcutaneous genistein. 3-BC and 4-MBC displaced 16α 125 I-estradiol from porcine uterine cytosolic receptors (IC 50 : 14.5 and 112 μM), and from recombinant human estrogen receptor β (hERβ) (IC 50 : 3-BC, 11.8 μM; 4-MBC, 35.3 μM), whereas no displacement was detected at human estrogen receptor α (hERα) up to 3 mM. This subtype selectivity makes the two camphor derivatives interesting model compounds. Their activity on immature rat uterus is not easily explained by ERβ activation. It cannot be excluded that active metabolites with possibly different receptor binding characteristics are formed in vivo

ChemSearch Journal

African Journals Online (AJOL)

Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives. Journal Homepage Image. Chemsearch Journal is a peer – reviewed journal that publishes original research work, scientific papers and technical reports in all the field of Chemistry (pure science, agriculture, environmental science, ...

Chem Gems & Joules

Science.gov (United States)

Mason, Diana S.

2002-09-01

Learn about the chemistry (and some physics) of optical discs such as CDs, CD-ROMs, and DVDs from David Birkett (p 1081). Beginning on p 1088, Johnson and Yalkowsky present some neat models (commercial or build-yourself) that assemble of their own accord into appropriate structures for liquid and solid water. Do you need a low-cost, small-scale heating device? How about adapting a soldering iron as described on p 1109? If you are interested in cooperative learning, the comparison with lecturing that begins on p 1131 will provide useful information. The latest in our series commemorating the centenary of the Nobel Prizes begins on p 1055. The many interconnections among the research of prizewinners described in this series provides interesting tidbits to humanize chemical kinetics. Do you have hydrogen peroxide, sulfur, or potassium chromate in your lab or chemical storage area? Learn about hazards of these substances from the letter to the editor on p 1070 and the CLIPs on p 1063, p 1064, and p 1065. Finally, keep up with chemical education news at the ACS and the NSF by reading the statements of candidates for the ACS presidency (p 1036 and p 1037) and the commentary by Ellis on p 1034.

Benchmarking of AREVA BWR FDIC-PEZOG model against first BFE3 cycle 15 application of On-Line NobleChem results

International Nuclear Information System (INIS)

Pop, M.G.; Lamanna, L.S.; Hoornik, A.; Storey, G.C.; Lemons, J.F.

2015-01-01

The combination of AREVA's BWR FDIC-PEZOG tools allows the calculation of the total liftoff as a measure of fuel performance and a risk indicator for fuel reliability. The AREVA BWR FDIC tool is a crud modeling tool. The PEZOG tool models the platinum-enhanced zirconium oxide growth of fuel cladding when exposed to platinum during operation. Continuous effort to improve these tools used for the total liftoff calculations is illustrated by the benchmarking of the tools after the application of On-Line NobleChem TM at TVA Browns Ferry Unit 3 during Cycle 15. A set of runs using the modified FDIC-PEZOG model and actual plant water chemistry for Cycle 15 and partial data for Cycle 16 were performed. The updated results' deposit thickness and deposit composition predictions for EOC15 were compared to the measured data from EOC15 and are presented in this paper. The updated predicted deposit thickness matched the actual, measured value exactly. Predicted deposit composition near the fuel rod boundary, nearer to the bulk reactor water, and as an averaged deposit, as presented in the paper, compared extremely well with the measured data at EOC15. The updated AREVA methodology resulted in lower fuel oxide thickness predictions over the life of the fuel as compared to the initial evaluations for BFE3 by incorporating more recent experimental data on the thermal conductivity of zirconia; unnecessary conservatism in the prediction of the fuel oxide thickness over the life of the fuel was removed in the improved model. (authors)

Coupling spectral-bin cloud microphysics with the MOSAIC aerosol model in WRF-Chem: Methodology and results for marine stratocumulus clouds

Science.gov (United States)

Gao, Wenhua; Fan, Jiwen; Easter, R. C.; Yang, Qing; Zhao, Chun; Ghan, Steven J.

2016-09-01

Aerosol-cloud interaction processes can be represented more physically with bin cloud microphysics relative to bulk microphysical parameterizations. However, due to computational power limitations in the past, bin cloud microphysics was often run with very simple aerosol treatments. The purpose of this study is to represent better aerosol-cloud interaction processes in the Chemistry version of Weather Research and Forecast model (WRF-Chem) at convection-permitting scales by coupling spectral-bin cloud microphysics (SBM) with the MOSAIC sectional aerosol model. A flexible interface is built that exchanges cloud and aerosol information between them. The interface contains a new bin aerosol activation approach, which replaces the treatments in the original SBM. It also includes the modified aerosol resuspension and in-cloud wet removal processes with the droplet loss tendencies and precipitation fluxes from SBM. The newly coupled system is evaluated for two marine stratocumulus cases over the Southeast Pacific Ocean with either a simplified aerosol setup or full-chemistry. We compare the aerosol activation process in the newly coupled SBM-MOSAIC against the SBM simulation without chemistry using a simplified aerosol setup, and the results show consistent activation rates. A longer time simulation reinforces that aerosol resuspension through cloud drop evaporation plays an important role in replenishing aerosols and impacts cloud and precipitation in marine stratocumulus clouds. Evaluation of the coupled SBM-MOSAIC with full-chemistry using aircraft measurements suggests that the new model works realistically for the marine stratocumulus clouds, and improves the simulation of cloud microphysical properties compared to a simulation using MOSAIC coupled with the Morrison two-moment microphysics.

Environment

DEFF Research Database (Denmark)

Valentini, Chiara

2017-01-01

The term environment refers to the internal and external context in which organizations operate. For some scholars, environment is defined as an arrangement of political, economic, social and cultural factors existing in a given context that have an impact on organizational processes and structures....... For others, environment is a generic term describing a large variety of stakeholders and how these interact and act upon organizations. Organizations and their environment are mutually interdependent and organizational communications are highly affected by the environment. This entry examines the origin...... and development of organization-environment interdependence, the nature of the concept of environment and its relevance for communication scholarships and activities....

Disease: H00203 [KEGG MEDICUS

Lifescience Database Archive (English)

Full Text Available 2680 ... AUTHORS ... Ogata M, Wang DH, Ogino K ... TITLE ... Mammalian acatalasemia: the perspectives of bioinformatics and genetic toxicol...ogy. ... JOURNAL ... Acta Med Okayama 62:345-61 (2008) ... PMID

Simulation of Mexico City plumes during the MIRAGE-Mex field campaign using the WRF-Chem model

Directory of Open Access Journals (Sweden)

X. Tie

2009-07-01

Full Text Available The quantification of tropospheric O₃ production in the downwind of the Mexico City plume is a major objective of the MIRAGE-Mex field campaign. We used a regional chemistry-transport model (WRF-Chem to predict the distribution of O₃ and its precursors in Mexico City and the surrounding region during March 2006, and compared the model with in-situ aircraft measurements of O₃, CO, VOCs, NO_x, and NO_y concentrations. The comparison shows that the model is capable of capturing the timing and location of the measured city plumes, and the calculated variability along the flights is generally consistent with the measured results, showing a rapid increase in O₃ and its precursors when city plumes are detected. However, there are some notable differences between the calculated and measured values, suggesting that, during transport from the surface of the city to the outflow plume, ozone mixing ratios are underestimated by about 0–25% during different flights. The calculated O₃-NO_x, O₃-CO, and O₃-NO_z correlations generally agree with the measured values, and the analyses of these correlations suggest that photochemical O₃ production continues in the plume downwind of the city (aged plume, adding to the O₃ already produced in the city and exported with the plume. The model is also used to quantify the contributions to OH reactivity from various compounds in the aged plume. This analysis suggests that oxygenated organics (OVOCs have the highest OH reactivity and play important roles for the O₃ production in the aging plume. Furthermore, O₃ production per NO_x molecule consumed (O₃ production efficiency is more efficient in the aged plume than in the young plume near the city. The major contributor to the high O₃ production efficiency in the aged plume is the

Contributions of foreign, domestic and natural emissions to US ozone estimated using the path-integral method in CAMx nested within GEOS-Chem

Directory of Open Access Journals (Sweden)

A. M. Dunker

2017-10-01

Full Text Available The Goddard Earth Observing System global chemical transport (GEOS-Chem model was used at 2°  ×  2.5° resolution to simulate ozone formation for a base case representing year 2010 and a natural background case without worldwide anthropogenic emissions. These simulations provided boundary concentrations for base and natural background simulations with the Comprehensive Air Quality Model with Extensions (CAMx on a North American domain (one-way nested at 12 km  ×  12 km resolution over March–September 2010. The predicted maximum daily average 8 h (MDA8 background ozone for the US is largest in the mountainous areas of Colorado, New Mexico, Arizona, and California. The background MDA8 ozone in some of these locations exceeds 60 ppb, when averaged over the 10 days with the largest base-case ozone (T10base average. The background ozone generally becomes both a larger fraction of the base-case ozone in the western US and a smaller fraction in the eastern US when proceeding from spring to summer to the T10base average. The ozone difference between the base and background cases represents the increment to ozone from all anthropogenic sources. The path-integral method was applied to allocate this anthropogenic ozone increment to US anthropogenic emissions, Canadian/Mexican anthropogenic emissions, and the anthropogenic components of the lateral and top boundary concentrations (BCs. Using the T10base average MDA8 ozone, the relative importance of the sources is generally US emissions  >  anthropogenic lateral BCs  >  Canadian/Mexican emissions  ≫  anthropogenic top BCs. Specifically, for 10 US urban areas, the source contributions were 12–53 ppb for US emissions, 3–9 ppb for lateral BCs, 0.2–3 ppb for Canadian/Mexican emissions, and  ≤  0.1 ppb for top BCs. The contributions of the lateral BCs are largest for the higher-elevation US sites in the Intermountain West and along the

Application of WRF/Chem-MADRID and WRF/Polyphemus in Europe - Part 1: Model description, evaluation of meteorological predictions, and aerosol-meteorology interactions

Science.gov (United States)

Zhang, Y.; Sartelet, K.; Wu, S.-Y.; Seigneur, C.

2013-07-01

Comprehensive model evaluation and comparison of two 3-D air quality modeling systems (i.e., the Weather Research and Forecast model (WRF)/Polyphemus and WRF with chemistry and the Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution (MADRID) (WRF/Chem-MADRID)) are conducted over Western Europe. Part 1 describes the background information for the model comparison and simulation design, the application of WRF for January and July 2001 over triple-nested domains in Western Europe at three horizontal grid resolutions: 0.5°, 0.125°, and 0.025°, and the effect of aerosol/meteorology interactions on meteorological predictions. Nine simulated meteorological variables (i.e., downward shortwave and longwave radiation fluxes (SWDOWN and LWDOWN), outgoing longwave radiation flux (OLR), temperature at 2 m (T2), specific humidity at 2 m (Q2), relative humidity at 2 m (RH2), wind speed at 10 m (WS10), wind direction at 10 m (WD10), and precipitation (Precip)) are evaluated using available observations in terms of spatial distribution, domainwide daily and site-specific hourly variations, and domainwide performance statistics. The vertical profiles of temperature, dew points, and wind speed/direction are also evaluated using sounding data. WRF demonstrates its capability in capturing diurnal/seasonal variations and spatial gradients and vertical profiles of major meteorological variables. While the domainwide performance of LWDOWN, OLR, T2, Q2, and RH2 at all three grid resolutions is satisfactory overall, large positive or negative biases occur in SWDOWN, WS10, and Precip even at 0.125° or 0.025° in both months and in WD10 in January. In addition, discrepancies between simulations and observations exist in T2, Q2, WS10, and Precip at mountain/high altitude sites and large urban center sites in both months, in particular, during snow events or thunderstorms. These results indicate the model's difficulty in capturing meteorological variables in complex terrain and

Origins of energetic ions in the Earth's magnetosheath. Final Report, 8 May 1991 - 5 Jun. 1992

International Nuclear Information System (INIS)

Fuselter, S.A.; Shelley, E.G.; Klumpar, D.M.

1992-06-01

The analysis and interpretation of the combined scientific data from the Hot Plasma Composition Experiment (HPCE) and the Charge Energy Mass (CHEM) spectrometer on the Active Mesospheric Particle Tracer Experiment (AMPTE) Charge Composition Explorer (CCE) spacecraft are discussed. These combined data sets have and will be used to survey the energetic ion environment in the Earth's magnetosheath to determine the origins and relative strengths of the energetic ion populations found there. A computer code was developed to analyze and interpret the data sets. The focus of the first year was on the determination of the contribution of leaked magnetospheric protons to the total energetic proton population. Emphasis was placed on intervals when the AMPTE spacecraft was in the plasma depletion layer because it was argued that in this region, only the leaked population contributes to the energetic ion population. Manipulation of the CHEM data and comparison of the CHEM and HPCE data over their common energy range near the magnetopause also contributed directly to a second study of that region