WorldWideScience

Sample records for biological fate transport

  1. The binding, transport and fate of aluminium in biological cells.

    Science.gov (United States)

    Exley, Christopher; Mold, Matthew J

    2015-04-01

    Aluminium is the most abundant metal in the Earth's crust and yet, paradoxically, it has no known biological function. Aluminium is biochemically reactive, it is simply that it is not required for any essential process in extant biota. There is evidence neither of element-specific nor evolutionarily conserved aluminium biochemistry. This means that there are no ligands or chaperones which are specific to its transport, there are no transporters or channels to selectively facilitate its passage across membranes, there are no intracellular storage proteins to aid its cellular homeostasis and there are no pathways which evolved to enable the metabolism and excretion of aluminium. Of course, aluminium is found in every compartment of every cell of every organism, from virus through to Man. Herein we have investigated each of the 'silent' pathways and metabolic events which together constitute a form of aluminium homeostasis in biota, identifying and evaluating as far as is possible what is known and, equally importantly, what is unknown about its uptake, transport, storage and excretion.

  2. Biological fate, transport, and ecotoxicity of toxic and hazardous waste in the Mississippi River Basin

    International Nuclear Information System (INIS)

    The objective of the cluster investigators is to develop a dynamic model for the evaluation of the biological fate, transport, and ecotoxicity from multiple chemical contamination of the Mississippi River Basin. To develop this environmental model, FY 93-94 most of cluster investigators focused on Devil's Swamp Site (DSS), a cypress swamp which lies just Northwest of Baton Rouge, Louisiana, adjacent to the Mississippi River. The DSS which includes a man-made lake has contaminated sediment, water and biota. The DSS receives flood water from the Mississippi River during high flow periods and the Baton Rouge Bayou drains through the DSS. The DSS receives toxic substances and hazardous waste from a wide variety of surrounding industrial operations including an abandoned hazardous waste disposal facility. In addition, some investigators studied Bayou Trepangnier. This research cluster will continue studying Devil Swamp. The large number of investigators in this cluster resulted from incorporating related research proposals based on reviewer recommendations. The specific aims of the cluster for the first year were to conduct a physical, chemical, ecological survey and baseline toxicological characterization of the DSS from existing databases maintained by State and federal agencies, field studies (assessment) of sediment, air, water and biota, and laboratory screening studios. This assessment will provide critical information and focus for the next two years in-depth studies of critical transport and fate processes, ecotoxicity, biomarkers of effect, and uptake, metabolism and distribution of toxicants. The primary significant outcome of the cluster researchers will be the development of an ecological risk assessment model combining biotic and physical/chemical variables for DSS with a projection of model reliability and accuracy for use at other typical Mississippi River Basin sites

  3. Survey and discussion of models applicable to the transport and fate thrust area of the Department of Energy Chemical and Biological Nonproliferation Program

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-09-01

    The availability and easy production of toxic chemical and biological agents by domestic and international terrorists pose a serious threat to US national security, especially to civilian populations in and around urban areas. To address this threat, the Department of Energy (DOE) has established the Chemical and Biological Nonproliferation Program (CBNP) with the goal of focusing the DOE`s technical resources and expertise on capabilities to deny, deter, mitigate and respond to clandestine releases of chemical and biological agents. With the intent to build on DOE core competencies, the DOE has established six technology thrust areas within the CBNP Program: Biological Information Resources; Point Sensor Systems; Stand-off Detection; Transport and Fate; Decontamination; and Systems Analysis and Integration. The purpose of the Transport and Fate Thrust is to accurately predict the dispersion, concentration and ultimate fate of chemical and biological agents released into the urban and suburban environments and has two major goals: (1) to develop an integrated and validated state-of-the-art atmospheric transport and fate modeling capability for chemical and biological agent releases within the complex urban environment from the regional scale down to building and subway interiors, and (2) to apply this modeling capability in a broad range of simulation case studies of chemical and biological agent release scenarios in suburban, urban and confined (buildings and subways) environments and provide analysis for the incident response user community. Sections of this report discuss subway transport and fate models; buildings interior transport and fate modeling; models for flow and transport around buildings; and local-regional meteorology and dispersion models.

  4. Biotic and abiotic studies on the biological fate, transport and ecotoxicity of toxic and hazardous waste in the Mississippi River basin

    Energy Technology Data Exchange (ETDEWEB)

    Abdelghani, A.; Pramar, Y.; Mandal, T.

    1996-05-02

    This project assesses the levels of xenobiotics in Devils Swamp and studies their biological fate, transport, ecotoxicity, and potential toxicity to man. This article reports on the following studies: assessment of the acute toxicity of individual xenobiotics and toxicity of organic compounds hexachlorobutadience (HCB) and hexachlorobenzene (HCBD) on juvenile crayfish; determination of the biotic influence of temperature, salinity, pH, oxidation-reduction potential, and sediment composition on the migration of xenobiotics; development of a pharmacokinetics model for xenobiotic absorption and storage, distribution and excretion by fish and crayfish.

  5. Occurrence and fate of tetracycline and degradation products in municipal biological wastewater treatment plant and transport of them in surface water.

    Science.gov (United States)

    Topal, Murat; Arslan Topal, E Işıl

    2015-12-01

    The aims of this study are to investigate the fate of tetracycline (TC) and degradation products (DPs) in municipal biological wastewater treatment plant (MBWWTP) located in Elazığ City (Turkey) and to determine the occurrence and transport of TC and DPs in surface water (SW) (Kehli Stream) which the effluents of the plant discharged. The aqueous phase removal of TC, 4-epitetracycline (ETC), 4-epianhydrotetracycline (EATC), and anhydrotetracycline (ATC) in the studied treatment plant was 39.4 ± 1.9, 31.8 ± 1.5, 15.1 ± 0.7, and 16.9 ± 0.8%, respectively. According to the analyses' results of SW samples taken from downstream at every 500-m distance, TC and DPs decreased by the increase in the distance. In downstream, at 2000 m, TC, ETC, EATC, and ATC were 4.12 ± 0.20, 6.70 ± 0.33, 8.31 ± 0.41, and 3.57 ± 0.17 μg/L, respectively. As a result, antibiotic pollution in the SW that takes the effluent of MBWWTP exists.

  6. Transport, behavior, and fate of volatile organic compounds in streams

    Science.gov (United States)

    Rathbun, R.E.

    2000-01-01

    Volatile organic compounds (VOCs) are compounds with chemical and physical properties that allow the compounds to move freely between the water and air phases of the environment. VOCs are widespread in the environment because of this mobility. Many VOCs have properties that make them suspected or known hazards to the health of humans and aquatic organisms. Consequently, understanding the processes affecting the concentration and distribution of VOCs in the environment is necessary. The transport, behavior, and fate of VOCs in streams are determined by combinations of chemical, physical, and biological processes. These processes are volatilization, absorption, wet and dry deposition, microbial degradation, sorption, hydrolysis, aquatic photolysis, oxidation, chemical reaction, biocon-centration, advection, and dispersion. The relative importance of each of these processes depends on the characteristics of the VOC and the stream. The U.S. Geological Survey National Water-Quality Assessment Program selected 55 VOCs for study. This article reviews the characteristics of the various processes that could affect the transport, behavior, and fate of these VOCs in streams.

  7. Emerging Pollutants - Part I: Occurrence, Fate and Transport.

    Science.gov (United States)

    Qiu, Lang; Dong, Zhanfeng; Sun, Huan; Li, Hongxiang; Chang, Chein-Chi

    2016-10-01

    Part I: Occurrence, Fate, and Transport (this review) is a sequel of Emerging Pollutants. This review compiles research in 2015 for investigating emerging pollutants in wastewater and environmental sources of emerging pollutants. It investigates the occurrence, fate, transport of emerging pollutants in the environment. This review further discusses the monitoring approaches, modeling, and toxicological impacts of these compounds that are relevant to wastewater. PMID:27620111

  8. Geochemical Fate and Transport of Sildenafil and Vardenafil

    Science.gov (United States)

    Richter, L.; Boudinot, G.; Vulava, V. M.; Cory, W. C.

    2015-12-01

    The geochemical fate of pharmaceuticals and their degradation products is a developing environmental field. The geologic, chemical, and biological fate of these pollutants has become very relevant with the increase in human population and the resulting increase in pollutant concentrations in the environment. In this study, we focus on sildenafil (SDF) and vardenafil (VDF), active compounds in Viagra and Levitra, respectively, two commonly used erectile dysfunction drugs. The main objective is to determine the sorption potential and transport behavior of these two compounds in natural soils. Both SDF and VDF are complex organic molecules with multiple amine functional groups in their structures. Two types of natural acidic soils (pH≈4.5), an organic-rich soil (7.6% OM) and clay-rich soil (5.1% clay) were used in this study to determine which soil components influence sorption behavior of both compounds. Sorption isotherms measured using batch reactors were nearly linear, but sorption was stronger in soil that contained higher clay content. Both compounds have multiple pKas due to the amine functional groups, the relevant pKas of SDF are 5.97 and 7.27, and those of VDF's are 4.72 and 6.21. These values indicate that these compounds likely behave as cations in soil suspensions and hence were strongly sorbed to negatively-charged clay minerals present in both soils. The clay composition in both soils is predominantly kaolinite with smaller amount of montmorillonite, both of which have a predominantly negative surface charge. Transport experiments using glass chromatography columns indicated that both compounds were more strongly retarded in the clay-rich soils. Breakthrough curves from the transport experiments were modeled using convection-dispersion transport equations. The organic matter in the soil seemed to play a less dominant role in the geochemistry in this study, but is likely to transform both compounds into derivative compounds as seen in other studies.

  9. Models of Fate and Transport of Pollutants in Surface Waters

    Science.gov (United States)

    Okome, Gloria Eloho

    2013-01-01

    There is the need to answer very crucial questions of "what happens to pollutants in surface waters?" This question must be answered to determine the factors controlling fate and transport of chemicals and their evolutionary state in surface waters. Monitoring and experimental methods are used in establishing the environmental states.…

  10. Fate and transport of manure-borne microorganisms

    Science.gov (United States)

    This lecture presents the overview of the recent research results on the environmental microbial fate and transport in the Environmental Microbial and Food Safety Laboratory. The overview of experimental sites in Maryland and Pennsylvania, and laboratory setups will be given. The emphasis on envir...

  11. Building 235-F Goldsim Fate And Transport Model

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, G. A.; Phifer, M. A.

    2012-09-14

    Savannah River National Laboratory (SRNL) personnel, at the request of Area Completion Projects (ACP), evaluated In-Situ Disposal (ISD) alternatives that are under consideration for deactivation and decommissioning (D&D) of Building 235-F and the Building 294-2F Sand Filter. SRNL personnel developed and used a GoldSim fate and transport model, which is consistent with Musall 2012, to evaluate relative to groundwater protection, ISD alternatives that involve either source removal and/or the grouting of portions or all of 235-F. This evaluation was conducted through the development and use of a Building 235-F GoldSim fate and transport model. The model simulates contaminant release from four 235-F process areas and the 294-2F Sand Filter. In addition, it simulates the fate and transport through the vadose zone, the Upper Three Runs (UTR) aquifer, and the Upper Three Runs (UTR) creek. The model is designed as a stochastic model, and as such it can provide both deterministic and stochastic (probabilistic) results. The results show that the median radium activity concentrations exceed the 5 ?Ci/L radium MCL at the edge of the building for all ISD alternatives after 10,000 years, except those with a sufficient amount of inventory removed. A very interesting result was that grouting was shown to basically have minimal effect on the radium activity concentration. During the first 1,000 years grouting may have some small positive benefit relative to radium, however after that it may have a slightly deleterious effect. The Pb-210 results, relative to its 0.06 ?Ci/L PRG, are essentially identical to the radium results, but the Pb-210 results exhibit a lesser degree of exceedance. In summary, some level of inventory removal will be required to ensure that groundwater standards are met.

  12. Assessing the transport and fate of bioengineered microorganisms in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Barnthouse, L.W.; Palumbo, A.V.

    1985-01-01

    We review the methods currently available for quantifying the transport and fate of microbes in atmospheric and aqueous media and assess their adequacy for purposes of risk assessment. We review the literature on transport and fate of microorganisms, including studies of: (1) pathways of migration, (2) the survival of microorganisms during transport and fate. In addition, we review the transport and fate models that have been used in environmental risk assessments for radionuclides and toxic chemicals and evaluate their applicability to the problem of assessing environmental risks of bioengineered microorganisms.

  13. Assessing the transport and fate of bioengineered microorganisms in the environment

    International Nuclear Information System (INIS)

    We review the methods currently available for quantifying the transport and fate of microbes in atmospheric and aqueous media and assess their adequacy for purposes of risk assessment. We review the literature on transport and fate of microorganisms, including studies of: (1) pathways of migration, (2) the survival of microorganisms during transport and fate. In addition, we review the transport and fate models that have been used in environmental risk assessments for radionuclides and toxic chemicals and evaluate their applicability to the problem of assessing environmental risks of bioengineered microorganisms

  14. A Bayesian network model for assessing natural estrogen fate and transport in a swine waste lagoon.

    Science.gov (United States)

    Lee, Boknam; Kullman, Seth W; Yost, Erin; Meyer, Michael T; Worley-Davis, Lynn; Williams, C Michael; Reckhow, Kenneth H

    2014-10-01

    Commercial swine waste lagoons are regarded as a major reservoir of natural estrogens, which have the potential to produce adverse physiological effects on exposed aquatic organisms and wildlife. However, there remains limited understanding of the complex mechanisms of physical, chemical, and biological processes that govern the fate and transport of natural estrogens within an anaerobic swine lagoon. To improve lagoon management and ultimately help control the offsite transport of these compounds from swine operations, a probabilistic Bayesian network model was developed to assess natural estrogen fate and budget and then compared against data collected from a commercial swine field site. In general, the model was able to describe the estrogen fate and budget in both the slurry and sludge stores within the swine lagoon. Sensitivity analysis within the model demonstrated that the estrogen input loading from the associated barn facility was the most important factor in controlling estrogen concentrations within the lagoon slurry storage, whereas the settling rate was the most significant factor in the lagoon sludge storage. The degradation reactions were shown to be minor in both stores based on prediction of average total estrogen concentrations. Management scenario evaluations demonstrated that the best possible management options to reduce estrogen levels in the lagoon are either to adjust the estrogen input loading from swine barn facilities or to effectively enhance estrogen bonding with suspended solids through the use of organic polymers or inorganic coagulants.

  15. A Bayesian network model for assessing natural estrogen fate and transport in a swine waste lagoon.

    Science.gov (United States)

    Lee, Boknam; Kullman, Seth W; Yost, Erin; Meyer, Michael T; Worley-Davis, Lynn; Williams, C Michael; Reckhow, Kenneth H

    2014-10-01

    Commercial swine waste lagoons are regarded as a major reservoir of natural estrogens, which have the potential to produce adverse physiological effects on exposed aquatic organisms and wildlife. However, there remains limited understanding of the complex mechanisms of physical, chemical, and biological processes that govern the fate and transport of natural estrogens within an anaerobic swine lagoon. To improve lagoon management and ultimately help control the offsite transport of these compounds from swine operations, a probabilistic Bayesian network model was developed to assess natural estrogen fate and budget and then compared against data collected from a commercial swine field site. In general, the model was able to describe the estrogen fate and budget in both the slurry and sludge stores within the swine lagoon. Sensitivity analysis within the model demonstrated that the estrogen input loading from the associated barn facility was the most important factor in controlling estrogen concentrations within the lagoon slurry storage, whereas the settling rate was the most significant factor in the lagoon sludge storage. The degradation reactions were shown to be minor in both stores based on prediction of average total estrogen concentrations. Management scenario evaluations demonstrated that the best possible management options to reduce estrogen levels in the lagoon are either to adjust the estrogen input loading from swine barn facilities or to effectively enhance estrogen bonding with suspended solids through the use of organic polymers or inorganic coagulants. PMID:24798317

  16. Transport and Fate of Organic and Inorganic Nitrogen from Biosolids leachates

    Science.gov (United States)

    Ilani, Talli; Trifonov, Pavel; Arye, Gilboa

    2014-05-01

    The use of biosolids as a means to ameliorate soil becomes prevalent in the last few years. In agricultural fields, the application of biosolids will be followed by irrigation; resulting in excessive leaching of the dissolved fraction of the organic matter. The dissolved organic matter (DOM) is one of the major players in the chemical, physical and biological processes in soils. The DOM mainly composed of dissolved organic carbon (DOC) and lower proportions of dissolved organic nitrogen (DON) and phosphate (DOP). The DON is considered to be the primary source of mineralisable nitrogen in the soil and can be used as an estimate of the nitrogen supplying capacity of the organic matter. Most of the researches which are dealing with nitrogen fate in terrestrial environments focused on its inorganic fractions (mainly nitrate and ammonium) and their transport toward the dipper soil layers. Since DON can be the source of the inorganic nitrogen (by providing nutrients and energy to nitrifying microbes, which in turn increases the nitrogen source for plants as nitrate), knowledge about the nature of its transport characteristics in the soil is important in the case of biosolids amendment. In addition, irrigation water quality (e.g. fresh water, wastewater or desalinized water) may significantly affect the transport and fate of the various nitrogen forms. The main objective of this study is to examine the fate and co-transport of organic and inorganics nitrogen, originating from biosolids leachates in the subsoil. The effect of water quality and flow rate under saturated steady-state flow is examined by a series of flow-through soil column experiments. The established breakthrough curves of the co-transport of total nitrogen, organic nitrogen (will be calculated from the differences between the total nitrogen measurements and the inorganic nitrogen measurements), nitrate, ammonium, dissolved organic carbon and chloride is presented and discussed.

  17. EVALUATION OF THE STATE-OF-THE-ART CONTAMINATED SEDIMENT TRANSPORT AND FATE MODELING SYSTEM

    Science.gov (United States)

    Modeling approaches for evaluating the transport and fate of sediment and associated contaminants are briefly reviewed. The main emphasis is on: 1) the application of EFDC (Environmental Fluid Dynamics Code), the state-of-the-art contaminated sediment transport and fate public do...

  18. Nitrogen fate and Transport in Diverse Agricultural Watersheds

    Science.gov (United States)

    Essaid, H.; McCarthy, K. A.; Baker, N. T.

    2010-12-01

    Nitrogen mass budgets have been estimated for ten agricultural watersheds located in a range of hydrologic settings in order to understand the factors controlling the fate of nitrogen applied at the surface. The watersheds, study areas of the Agricultural Chemical Sources, Transport and Fate study of the U.S. Geological Survey National Water Quality Assessment Program, are located in Indiana (IN), Iowa (IA), Maryland (MD), Nebraska (NE), Mississippi (MS) and Washington (WA). They range in size from 7 to 1254 km2, with four of the watersheds nested within larger watersheds. Surface water outflow (normalized to watershed area) ranged from 4 to 83 cm/yr. Crops planted include corn, soybean, small grains, rice, cotton, orchards and vegetables. “Surplus nitrogen” was determined for each watershed by subtracting estimates of crop uptake and volatilization from estimates of nitrogen input from atmospheric deposition, plant fixation, and fertilizer and manure applications for the period from 1987 to 2004. This surplus nitrogen is transported though the watershed via surface and subsurface flow paths, while simultaneously undergoing transformations (such as denitrification and in-stream processing) that result in less export of nitrogen from the watershed. Surface-water discharge and concentration data were used to estimate the export of nitrogen from the watersheds (groundwater outflow from the watersheds was minimal). Subtracting nitrogen export from surplus nitrogen provides an estimate of the net amount of nitrogen removal occurring during internal watershed transport. Watershed average nitrogen surplus ranged from 6 to 49 kg-N/ha. The more permeable and/or greater water flux watersheds (MD, NE, and WA) tended to have larger surplus nitrogen, possibly due to less crop uptake caused by greater leaching and runoff of nitrogen. Almost all of the surplus nitrogen in the low permeability (MS) and tile drained watersheds (IA, IN) was exported from the watershed with

  19. FATE AND TRANSPORT OF PETROLEUM RELEASED FROM UNDERGROUND STORAGE TANKS in Areas of Karst Topography

    Science.gov (United States)

    The study determines the transport and ultimate fate of petroleum products within a region of karst geomorphology. The paper entails a complete literature review, including references that pertain to contaminant transport within karst aquifers

  20. Geochemical Fate and Transport of Diphenhydramine and Cetirizine in Soil

    Science.gov (United States)

    Wireman, R.; Rutherford, C. J.; Vulava, V. M.; Cory, W. C.

    2015-12-01

    Pharmaceuticals compounds presence in natural soils and water around the world has become a growing concern. These compounds are being discharged into the environment through treated wastewater or municipal sludge applications. The main goal of this study is determine their geochemical fate in natural soils. In this study we investigated sorption and transport behavior of diphenhydramine (DPH) and cetirizine (CTZ) in natural soils. These two commonly-used antihistamines are complex aromatic hydrocarbons with polar functional groups. Two clean acidic soils (pH~4.5) were used for these studies - an A-horizon soil that had higher organic matter content (OM, 7.6%) and a B-horizon soil that had lower OM (1.6%), but higher clay content (5.1%). Sorption isotherms were measured using batch reactor experiments. Data indicated that sorption was nonlinear and that it was stronger in clay-rich soils. The pKa's of DPH and CTZ are 8.98 and 8.27 respectively, i.e., these compounds are predominantly in cationic form at soil pH. In these forms, they preferentially sorb to negatively charged mineral surfaces (e.g., clay) present in the soils. Soil clay mineral characterization indicated that kaolinite was the dominant clay mineral present along with small amount of montmorillonite. The nonlinear sorption isotherms were fitted with Freundlich model. Transport behavior of both compounds was measured using glass chromatography columns. As expected both DPH and CTZ were strongly retained in the clay-rich soil as compared with OM-rich soil. The asymmetrical shape of the breakthrough curves indicated that there were likely two separate sorption sites in the soil, each with different reaction rates with each compound. A two-region advection-dispersion transport code was used to model the transport breakthrough curves. There was no evidence of transformation or degradation of the compounds during our sorption and transport studies.

  1. Atmospheric Fate and Transport of Agricultural Dust and Ammonia

    Science.gov (United States)

    Hiranuma, N.; Brooks, S. D.; Thornton, D. C.; Auvermann, B. W.; Fitz, D. R.

    2008-12-01

    Agricultural fugitive dust and odor are significant sources of localized air pollution in the semi-arid southern Great Plains. Daily episodes of ground-level fugitive dust emissions from the cattle feedlots associated with increased cattle activity in the early evenings are routinely observed, while consistently high ammonia is observed throughout the day. Here we present measurements of aerosol size distributions and concentrations of gas and particulate phase ammonia species collected at a feedlot in Texas during summers of 2006, 2007 and 2008. A GRIMM sequential mobility particle sizer and GRIMM 1.108 aerosol spectrometer were used to determine aerosol size distributions in the range of 10 nm to 20 µm aerodynamic diameter at the downwind and upwind edges of the facility. Using aqueous scrubbers, simultaneous measurements of both gas phase and total ammonia species present in the gas and particle phases were also collected. In addition to the continuous measurements at the edges of the facility, coincident aerosol and ammonia measurements were obtain at an additional site further downwind (~3.5 km). Taken together our measurements will be used to quantify aerosol and ammonia dispersion and transport. Relationships between the fate and transport of the aerosols and ammonia will be discussed.

  2. Modeling Nitrogen Fate and Transport at the Sediment-Water Interface

    Science.gov (United States)

    Diffusive mass transfer at media interfaces exerts control on the fate and transport of pollutants originating from agricultural and urban landscapes and affects the con-ditions of water bodies. Diffusion is essentially a physical process affecting the distribution and fate of va...

  3. Simulated fate and transport of metolachlor in the unsaturated zone, Maryland, USA

    Science.gov (United States)

    Bayless, E.R.; Capel, P.D.; Barbash, J.E.; Webb, R.M.T.; Hancock, T.L.C.; Lampe, D.C.

    2008-01-01

    An unsaturated-zone transport model was used to examine the transport and fate of metolachlor applied to an agricultural site in Maryland, USA. The study site was instrumented to collect data on soil-water content, soil-water potential, ground water levels, major ions, pesticides, and nutrients from the unsaturated zone during 2002-2004. The data set was enhanced with site-specific information describing weather, soils, and agricultural practices. The Root Zone Water Quality Model was used to simulate physical, chemical, and biological processes occurring in the unsaturated zone. Model calibration to bromide tracer concentrations indicated flow occurred through the soil matix. Simulated recharge rates were within the measured range of values. The pesticide transport model was calibrated to the intensive data collection period (2002-2004), and the calibrated model was then used to simulate the period 1984 through 2004 to examine the impact of sustained agricultural management practices on the concentrations of metolachlor and its degradates at the study site. Simulation results indicated that metolachlor degrades rapidly in the root zone but that the degradates are transported to depth in measurable quantities. Simulations indicated that degradate transport is strongly related to the duration of sustained use of metolachlor and the extent of biodegradation. 

  4. An ECHO in biology II: Insights in chondrocyte cell fate

    NARCIS (Netherlands)

    Schivo, S.; Scholma, J.; Huang, X.; Zhong, L.; Pol, van de J.C.; Karperien, H.B.J.; Langerak, R.; Post, J.N.

    2016-01-01

    Purpose: An intricate network of regulatory processes determines the chondrocyte cell fate during development and maintains tissue homeostasis. In the event of a disease such as OA, the regulatory network is critically compromised. To cure the disease, we need to restore the regulatory processes to

  5. Radionuclide fate and effects

    International Nuclear Information System (INIS)

    The studies reported here deal with the full range of contaminant behavior and fate, from the initial physicochemical factors that govern radionuclide availability in terrestrial and aquatic environments to studies of contaminant transport by biological means. By design, we focus more on the biologically and chemically mediated transport processes and food-chain pathways than on the purely physical forms of contaminant transport, such as transport by wind and water

  6. Fate and Transport of Cohesive Sediment and HCB in the Middle Elbe River Basin

    Science.gov (United States)

    Moshenberg, Kari; Heise, Susanne; Calmano, Wolfgang

    2014-05-01

    Chemical contamination of waterways and floodplains is a pervasive environmental problem that threatens aquatic ecosystems worldwide. Due to extensive historical contamination and redistribution of contaminated sediments throughout the basin, the Elbe River transports significant loads of contaminants downstream, particularly during flood events. This study focuses on Hexachlorobenzene (HCB), a persistent organic pollutant that has been identified as a contaminant of concern in the Elbe Basin. To better understand the fate and transport of cohesive sediments and sediment-sorbed HCB, a hydrodynamic, suspended sediment, and contaminated transport model for the 271-km reach of the Elbe River basin between Dresden and Magdeburg was developed. Additionally, trends in suspended sediment and contaminant transport were investigated in the context of the recent high frequency of floods in the Elbe Basin. This study presents strong evidence that extreme high water events, such as the August, 2002 floods, have a permanent effect on the sediment transport regime in the Elbe River. Additionally, results indicate that a significant component annual HCB loads are transported downstream during floods. Additionally, modeled results for suspended sediment and HCB accumulation on floodplains are presented and discussed. Uncertainty and issues related to model development are also addressed. A worst case analysis of HCB uptake by dairy cows and beef cattle indicate that significant, biologically relevant quantities of sediment-sorbed HCB accumulate on the Elbe floodplains following flood events. Given both the recent high frequency of floods in the Elbe Basin, and the potential increase in flood frequency due to climate change, an evaluation of source control measures and/or additional monitoring of floodplain soils and grasses is recommended.

  7. Emerging organic contaminants in sludges. Analysis, fate and biological treatment

    Energy Technology Data Exchange (ETDEWEB)

    Vicent, Teresa [Univ. Autonoma de Barcelona, Bellaterra (Spain). Chemical Engineering Dept.; Eljarrat, Ethel [IDAEA-CSIC, Barcelona (Spain). Dept. of Environmental Chemistry; Caminal, Gloria [IQAC-CSIC, Barcelona (Spain). Grupo de biocatalisis Aplicada y biodegradacion; Barcelo, Damia (eds.) [IDAEA-CSIC, Barcelona (Spain). Dept. of Environmental Chemistry; Girona Univ. (Spain). Catalan Inst. for Water Research

    2013-07-01

    A comprehensive review. Written by experts. Richly illustrated. There are a growing number of new chemicals in the environment that represent an ascertained or potential risk. Many of them can be found in sewage sludge and are the subject of this volume. Experts in the field highlight their occurrence and fate, risks of biosolid use, advanced chemical analysis methods, and degradation techniques with a special focus on biodegradation using fungi. In the final chapter conclusions and trends are offered as a point of departure for future studies. The double-disciplinary approach combining environmental analysis and engineering makes the book a valuable and comprehensive source of information for a broad audience, such as environmental chemists and engineers, biotechnologists, ecotoxicologists and professionals responsible for waste and water management.

  8. Fixable or Fate? Perceptions of the Biology of Depression

    Science.gov (United States)

    Lebowitz, Matthew S.; Ahn, Woo-Kyoung; Nolen-Hoeksema, Susan

    2013-01-01

    Objective: Previous research has shown that biological (e.g., genetic, biochemical) accounts of depression--currently in ascendancy--are linked to the general public's pessimism about the syndrome's prognosis. This research examined for the first time whether people with depressive symptoms would associate biological accounts of depression with…

  9. Material transport map of Titan: The fate of dunes

    Science.gov (United States)

    Malaska, Michael J.; Lopes, Rosaly M.; Hayes, Alex G.; Radebaugh, Jani; Lorenz, Ralph D.; Turtle, Elizabeth P.

    2016-05-01

    Using SAR data from Cassini's RADAR instrument, we examined the orientations of three terrain units on Titan, bright lineated plains, streak-like plains, and linear dunes. From the overall integrated pattern of their orientation, we were able to determine Titan's global material transport vectors. The analysis indicates that, in both the northern and southern hemispheres, materials from 0 to 35 deg latitude are transported poleward to a belt centred at roughly 35 deg. Materials from 60 to 35 deg latitude are transported equatorward to the belt at roughly 35 deg. Comparison with the global topographical gradient (Lorenz, R.D. et al. [2013]. Icarus 225, 367-377) suggests that fluvial transport is not the dominant process for material transport on Titan, or that it is at least overprinted with another transport mechanism. Our results are consistent with aeolian transport being the dominant mechanism in the equatorial and mid-latitude zones. The zone at 35 deg is thus the ultimate sink for materials from the equator to low polar latitudes; materials making up the equatorial dunes will be transported to the latitude 35-deg belts. Only plains units are observed at latitudes of ∼35 deg; dunes and materials with the spectral characteristics of dunes are not observed at these latitudes. This observation suggests that either dune materials are converted or modified into plains units or that the margins of dunes are transport limited.

  10. Fate and transport of viruses and colloids in saturated and unsaturated porous media

    NARCIS (Netherlands)

    Torkzaban, S.

    2007-01-01

    The fundamental mechanisms involved in fate and transport of colloidal particles (viruses and latex microspheres) in saturated and unsaturated porous media were systematically examined. Two different bacteriophages were used as surrogate for pathogenic viruses to investigate the effects of various w

  11. Modelling the occurrence, transport and fate of pharmaceuticals in wastewater systems

    DEFF Research Database (Denmark)

    Snip, Laura J.P.; Flores Alsina, Xavier; Plósz, Benedek Gy;

    2014-01-01

    This paper demonstrates how occurrence, transport and fate of pharmaceuticals at trace levels can be assessed when modelling wastewater treatment systems using two case studies. Firstly, two approaches based on: 1) phenomenology; and, 2) Markov Chains, are developed to describe the dynamics of ph...

  12. Lithium transport across biological membranes

    DEFF Research Database (Denmark)

    Holstein-Rathlou, N H

    1990-01-01

    Li+ is actively transported out of cells, and across different epithelia of both mammalian and amphibian origin. Due to the low affinity of the Na+/K(+)-ATPase for Li+, the transport is most likely energized by exchange and/or cotransport processes. The detailed mechanism by which Li+ is reabsorbed...

  13. Molecular Mechanism of Biological Proton Transport

    Energy Technology Data Exchange (ETDEWEB)

    Pomes, R.

    1998-09-01

    Proton transport across lipid membranes is a fundamental aspect of biological energy transduction (metabolism). This function is mediated by a Grotthuss mechanism involving proton hopping along hydrogen-bonded networks embedded in membrane-spanning proteins. Using molecular simulations, the authors have explored the structural, dynamic, and thermodynamic properties giving rise to long-range proton translocation in hydrogen-bonded networks involving water molecules, or water wires, which are emerging as ubiquitous H{sup +}-transport devices in biological systems.

  14. Biokinetics of zinc oxide nanoparticles: toxicokinetics, biological fates, and protein interaction

    Directory of Open Access Journals (Sweden)

    Choi SJ

    2014-12-01

    Full Text Available Soo-Jin Choi,1 Jin-Ho Choy2 1Department of Food Science and Technology, Seoul Women's University, 2Center for Intelligent Nano Bio Materials (CINBM, Department of Bioinspired Science and Department of Chemistry and Nanoscience, Ewha Womans University, Seoul, South Korea Abstract: Biokinetic studies of zinc oxide (ZnO nanoparticles involve systematic and quantitative analyses of absorption, distribution, metabolism, and excretion in plasma and tissues of whole animals after exposure. A full understanding of the biokinetics provides basic information about nanoparticle entry into systemic circulation, target organs of accumulation and toxicity, and elimination time, which is important for predicting the long-term toxic potential of nanoparticles. Biokinetic behaviors can be dependent on physicochemical properties, dissolution property in biological fluids, and nanoparticle–protein interaction. Moreover, the determination of biological fates of ZnO nanoparticles in the systemic circulation and tissues is critical in interpreting biokinetic behaviors and predicting toxicity potential as well as mechanism. This review focuses on physicochemical factors affecting the biokinetics of ZnO nanoparticles, in concert with understanding bioavailable fates and their interaction with proteins. Keywords: ZnO nanoparticles, biokinetics, distribution, excretion, fate, interaction

  15. Fate and Transport of CL-20 and RDX in Unsaturated Laboratory Columns

    Science.gov (United States)

    Lemond, L. A.; Gamerdinger, A. P.; Szecsody, J. E.

    2005-05-01

    This research examines the fate and transport of two explosive compounds, Hexanitrohexaazaisowurtzitane (CL-20) and Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in unsaturated laboratory columns. The transport and fate of these compounds were studied under saturated and unsaturated conditions in three natural soils: coarse sand, sandy loam, and a silt loam. Unsaturated column experiments were conducted using an ultra-centrifugation method. Sorption and degradation parameters were determined by moment analysis and hydrodynamic parameters were assessed with a two-region flow model. Differences in these parameters were evaluated as a function of water content. The fate and transport of CL-20 is highly dependent on 1) the soil type and 2) the compound's residence time in the soil and 3) water content of the media. Sorption of CL-20 was rate-limited. CL-20 degradation in saturated columns produced a half-life of as much as 22hr, but in unsaturated columns the degradation rate increased considerably, producing a half life of as little as 2hr. The fate and transport of RDX are also affected by the soil type, but sorption appeared to be instantaneous. Degradation of RDX was negligible. Our results suggest that at very low water content immobile water regions may become (at least in effect) isolated water regions and significantly alter the retardation of the tracer. In the sandy loam, there was as much as a 20-fold over-prediction of the retardation factor in the unsaturated saturated columns when predicted by Kd values derived from saturated columns. In the coarse sand, Kd values derived from saturated columns over-predicted retardation in the unsaturated columns by as much as 30%. In the silt loam, retardation factors were over-predicted by as much as 80%. At very low water contents, predictions of tracer behavior become very difficult because of changes in the flow regime that cannot be directly accounted for.

  16. Transport and fate of trifluoroacetate in upland forest and wetland ecosystems

    OpenAIRE

    Likens, G. E.; Tartowski, S. L.; Berger, T. W.; Richey, D. G.; Driscoll, C. T.; Frank, H. G.; De Klein, A.

    1997-01-01

    Although trifluoroacetate (TFA), a breakdown product of chlorofluorocarbon replacements, is being dispersed widely within the biosphere, its ecological fate is largely unknown. TFA was added experimentally to an upland, northern hardwood forest and to a small forest wetland ecosystem within the Hubbard Brook Experimental Forest in New Hampshire. Inputs of TFA were not transported conservatively through these ecosystems; instead, significant amounts of TFA were retained within the vegetation a...

  17. Fate and transport in the subsurface of radioactive waste

    Energy Technology Data Exchange (ETDEWEB)

    Collard, L.B.

    2000-01-27

    Disposal of tritium generation wastes in shallow, concrete vaults was modeled to determine aquifer concentrations created by advection and diffusion. A 10,000-year minimum duration was examined, hence material changes in waste containers, vaults and engineered barriers were accommodated in the simulations. Ground-water flow analyses were accomplished in three steady-state stages, representing the intact, cracked, and failed states of the concrete vaults. Radionuclide half-lives and Kds were major inputs to transient transport modeling that was performed to complete the analyses. Contaminant mass fluxes to the water table and concentrations at a hypothetical 100-m down-gradient well from the analyses of two radionuclides were presented displaying distinctively different behaviors.

  18. Development of an integrated model system to simulate transport and fate of oil spills in seas

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A three-dimensional integrated model is developed for simulating transport and final fate of oil spills in seas.The model contains two main modules,flow and transport-fate modules.The flow module uses an unstructured finite-volume wave-ocean coupling model.Using unstructured meshes provides great flexibility for modeling the flow in complex geometries of tidal creeks,barriers and islands.In the transport-fate module the oil dispersion is solved using a particle-tracking method.Horizontal diffusion is simulated using random walk techniques in a Monte Carlo framework,whereas the vertical diffusion process is solved on the basis of the Langeven equation.The model simulates the most significant processes that affect the motion of oil particles,such as advection,surface spreading,evaporation,dissolution,emulsification and turbulent diffusion as well as the interaction of the oil particles with the shoreline,sedimentation and the temporal variations of oil viscosity,density and surface tension.The model simulates either continuous or instantaneous oil spills,and also other toxic matter.This model has been applied to simulate the oil spill accident in the Bohai Sea.In comparison with the observations,the numerical results indicate that the model is reasonably accurate.

  19. A mercury transport and fate model (LM2-mercury) for mass budget assessment of mercury cycling in Lake Michigan

    Science.gov (United States)

    LM2-Mercury, a mercury mass balance model, was developed to simulate and evaluate the transport, fate, and biogeochemical transformations of mercury in Lake Michigan. The model simulates total suspended solids (TSS), disolved organic carbon (DOC), and total, elemental, divalent, ...

  20. TRANSPORT/FATE/ECOLOGICAL EFFECTS OF STEROIDS FROM POULTRY LITTER & EVALUATIONS OF EXISTING/NOVEL MANAGEMENT STRATEGIES

    Science.gov (United States)

    Laboratory assays will clarify exposure criteria required to induce previously observed steroid effects. Controlled field runoff studies will determine the abundance, chemical nature, and environmental fate of litter-associated steroids transported under various cropping stra...

  1. The transport and fate of riverine fine sediment exported to a semi-open system

    Science.gov (United States)

    Delandmeter, Philippe; Lewis, Stephen E.; Lambrechts, Jonathan; Deleersnijder, Eric; Legat, Vincent; Wolanski, Eric

    2015-12-01

    Understanding the transport and fate of suspended sediment exported by rivers is crucial for the management of sensitive marine ecosystems. Sediment transport and fate can vary considerably depending on the geophysical characteristics of the coastal environment. Fine sediment transport was studied in a setting in between "open" (uninterrupted coasts) and "semi-enclosed" (bays) coastal systems, namely a "semi-open" system of shallow coastal water with long (˜20 km) stretches of open coasts separated by capes and headlands. The case study was the large, seasonal, Burdekin River that discharges to a wide continental shelf containing headlands and shallow embayments adjacent to the Great Barrier Reef, Australia. A new three-dimensional fine sediment module for the unstructured-mesh SLIM 3D hydrodynamic model was developed. The model was successfully validated against available field data. The results were compared to previous studies on the Burdekin River sediment transport and differences were analysed. Wind direction and speed during river floods largely control the dynamics and the fate of the fine sediment. Most (67% for 2007) of the riverine fine sediment load is deposited near the river mouth; the remaining sediment is transported further afield in a riverine freshwater plume; that sediment can reach sensitive marine ecosystems and should be a priority for management. During the rest of the year, when the river flow has ceased, wind-driven resuspension events redistribute the deposited sediment within embayments but generate negligible longshore transport. This study suggests that semi-open systems trap most of the riverine fine sediment, somewhat like semi-enclosed systems.

  2. The fate and transport of reproductive hormones and their conjugates in the environment (Invited)

    Science.gov (United States)

    Casey, F. X.; Shrestha, S. L.; Hakk, H.; Smith, D. J.; Larsen, G. L.; Padmanabhan, G.

    2009-12-01

    Reproductive steroid hormones can disrupt the endocrine system of some species at ng/L concentrations. Sources of steroid hormones to the environment include human waste water effluents or manure produced at animal feeding operations (AFOs). Steroid hormones, such as 17β-estradiol (E2) and estrone (E1), undergo various fate and transport processes, and laboratory studies have shown that they do not persist long (hours to few days), and have very little if any mobility in soil. Nonetheless, steroid hormones are detected at frequencies and concentrations of concern in the natural environment that would suggest their moderate persistence and mobility. One theory that may partially explain the disparity between field and laboratory studies is that conjugated forms of hormones are more mobile than their deconjugated counterparts. Glucuronide and sulfate conjugates are found in abundance in animal waste and are more soluble than their deconjugated forms. Laboratory studies were conducted to study the fate of a major urinary E2 conjugate, 17β-estradiol glucuronide (E2G), in a Hamar soil (Sandy, mixed, frigid typic Endoaquolls) from the surface and subsurface horizons. Speciation studies using batch sorption indicated that E2G degraded to E2 and E1 within 24 hours in the upper horizon soil with organic carbon content (OC) of 1.35%; whereas it persisted more in the lower horizon soil containing 0.32% OC. For initial concentrations of 2.8-28 mg/L, more than 15% of the applied dose concentration was still intact in the conjugate form in the aqueous phase for 3 - 14 days, in the lower horizon soil. The decline of E2G in the aqueous phase in the upper horizon soil was approximated with a first-order rate constant (k), which ranged from -0.208 to -0.279/h. The k values ranged from -0.006 to -0.016/h for the lower soil horizon. The differences in k values between the two horizons could be attributed to differences in bacterial activity and/or differences in sorption capacities

  3. Advances in Understanding Sorption and Transport Processes Affecting the Fate of Environmental Pollutants in the Subsurface

    Science.gov (United States)

    Karapanagioti, H. K.; Werner, D.; Werth, C.

    2012-04-01

    The results of a call for a special issue that is now in press by the Journal of Contaminant Hydrology will be presented. This special issue is edited by the authors and is entitled "Sorption and Transport Processes Affecting the Fate of Environmental Pollutants in the Subsurface". A short abstract of each paper will be presented along with the most interesting results. Nine papers were accepted. Pollutants studied include: biocolloids, metals (arsenic, chromium, nickel), organic compounds such as hydrocarbons, chlorinated hydrocarbons, micropollutants (PAHs, PCBs), pesticides (glyphosate, 2,4-D). Findings presented in the papers include a modified batch reactor system to study equilibrium-reactive transport problems of metals. Column studies along with theoretical approximations evaluate the combined effects of grain size and pore water velocity on the transport in water saturated porous media of three biocolloids. A polluted sediment remediation method is evaluated considering site-specific conditions through monitoring results and modelling. A field study points to glogging and also sorption as mechanisms affecting the effectiveness of sub-surface flow constructed wetlands. A new isotherm model combining modified traditionally used isotherms is proposed that can be used to simulate pH-dependent metal adsorption. Linear free energy relationships (LFERs) demonstrate ability to predict slight isotope shifts into the groundwater due to sorption. Possible modifications that improve the reliability of kinetic models and parameter values during the evaluation of experiments that assess the sorption of pesticides on soils are tested. Challenges in selecting groundwater pollutant fate and transport models that account for the effect of grain-scale sorption rate limitations are evaluated based on experimental results and are discussed based on the Damköhler number. Finally, a thorough review paper presents the impact of mineral micropores on the transport and fate of

  4. Optimizing Nutrient Uptake in Biological Transport Networks

    Science.gov (United States)

    Ronellenfitsch, Henrik; Katifori, Eleni

    2013-03-01

    Many biological systems employ complex networks of vascular tubes to facilitate transport of solute nutrients, examples include the vascular system of plants (phloem), some fungi, and the slime-mold Physarum. It is believed that such networks are optimized through evolution for carrying out their designated task. We propose a set of hydrodynamic governing equations for solute transport in a complex network, and obtain the optimal network architecture for various classes of optimizing functionals. We finally discuss the topological properties and statistical mechanics of the resulting complex networks, and examine correspondence of the obtained networks to those found in actual biological systems.

  5. Biological contexts for DNA charge transport chemistry

    OpenAIRE

    Merino, Edward J.; Boal, Amie K.; Barton, Jacqueline K.

    2008-01-01

    Many experiments have now shown that double helical DNA can serve as a conduit for efficient charge transport (CT) reactions over long distances in vitro. These results prompt the consideration of biological roles for DNA-mediated CT. DNA CT has been demonstrated to occur in biologically relevant environments such as within the mitochondria and nuclei of HeLa cells as well as in isolated nucleosomes. In mitochondria, DNA damage that results from CT is funneled to a critical regulatory element...

  6. Models for transport and fate of carbon, nutrients and point source released radionuclides to an aquatic ecosystem

    International Nuclear Information System (INIS)

    In this report three ecosystem models are described in terms of structure, initial data, and results. All models are dynamic, mass-balanced and describe the transport and fate of elements in an open aquatic ecosystem. The models are based on ecologically sound principles, provide model results with high resolution and transparency, and are constrained by the nutrient dynamics of the ecosystem itself. The processes driving the transport in all the models are both the biological processes such as primary production, consumption, respiration and excretion, and abiotic e.g. water exchange and air-sea exchange. The first model, the CNP-model, describes the distribution and fluxes of carbon and nutrients for the coastal ecosystem off Forsmark. The second model, the C-14 model, is an extension of the CNP-model and describes the transport and distribution of hypothetically released C-14 from the underground repository SFR-1 to the ecosystem above. The third model, the RN-model, is a generic radionuclide flow model that models the transport and distribution of radionuclides other than C-14 hypothetically discharged to the ecosystem. The model also analyses the importance of some radionuclide specific mechanisms for the radionuclide flow. The generic radionuclide model is also based on the CNP-model, but has radionuclide specific mechanisms connected to each compartment

  7. Models for transport and fate of carbon, nutrients and point source released radionuclides to an aquatic ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Kumblad, Linda [Stockholm Univ. (Sweden). Dept. of Systems Ecology; Kautsky, Ulrik [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    2004-09-01

    In this report three ecosystem models are described in terms of structure, initial data, and results. All models are dynamic, mass-balanced and describe the transport and fate of elements in an open aquatic ecosystem. The models are based on ecologically sound principles, provide model results with high resolution and transparency, and are constrained by the nutrient dynamics of the ecosystem itself. The processes driving the transport in all the models are both the biological processes such as primary production, consumption, respiration and excretion, and abiotic e.g. water exchange and air-sea exchange. The first model, the CNP-model, describes the distribution and fluxes of carbon and nutrients for the coastal ecosystem off Forsmark. The second model, the C-14 model, is an extension of the CNP-model and describes the transport and distribution of hypothetically released C-14 from the underground repository SFR-1 to the ecosystem above. The third model, the RN-model, is a generic radionuclide flow model that models the transport and distribution of radionuclides other than C-14 hypothetically discharged to the ecosystem. The model also analyses the importance of some radionuclide specific mechanisms for the radionuclide flow. The generic radionuclide model is also based on the CNP-model, but has radionuclide specific mechanisms connected to each compartment.

  8. Monitoring the fate and transport of deicing chemicals in lysimeter experiments

    Science.gov (United States)

    Lißner, H.; Wehrer, M.; Totsche, K. U.

    2012-04-01

    Large amounts of the deicing chemicals (DIC) propylene glycol (PG) and formate are spread for removal of snow and ice on the aircrafts and airfields every winter. A considerable amount of these chemicals are carried into surrounding areas, where they mix with snow and infiltrate in the soil during snowmelt. Even though DIC are easily degradable, the high mobility and the high biological oxygen demand of PG in particular can influence the hydrogeochemistry of the unsaturated and saturated zone. The aims of the study were to evaluate and quantify transport of deicing chemicals during snowmelt under field conditions, and to study effects of DIC degradation on the hydrogeochemistry of the unsaturated zone. Eight undisturbed soil cores (0.3 m x 1 m, 0.071 m3) were retrieved at the Gardermoen Airport, Norway, and installed as non-weighable small scale lysimeters at a nearby field site. Before snowmelt in March 2010, a mix of snow containing 350 g/m2 PG, 71 g/m2 formate, and 17 g/m2 of bromide were added to the lysimeters. To determine the fate and transport of PG we monitored PG and its metabolites, bromide, manganese, and iron in the seepage water. High cumulative infiltration and marginal degradation of PG during the snowmelt period allowed up to 50 % of the PG to leave the upper, microbially most active, region of the soil. Only marginal concentrations of formate were analysed in all lysimeters, indicating fast degradation and favoured metabolism by soil bacteria compared to PG. Low contents of metabolites and the concurrent breakthrough of PG and Br in the seepage water even imply that PG was not significantly degraded before June. Redox values down to 200 mV in April, the detection of propionate and manganese, as well as a rise in pH, suggest partially anearobic localities in the soil, not only during high soil water saturation in April and May but also during summer when PG degradation was very efficient. In the longterm, the intense depletion of electron acceptors

  9. The Occurrence, Fate and Biological Activities of C-glycosyl Flavonoids in the Human Diet.

    Science.gov (United States)

    Courts, Fraser L; Williamson, Gary

    2015-01-01

    The human diet contains a wide variety of plant-derived flavonoids, many of which are glycosylated via an O- or less commonly a C-glycosidic linkage. The distribution, quantity, and biological effects of C-glycosyl flavonoids in the human diet have received little attention in the literature in comparison to their O-linked counterparts, however, despite being present in many common foodstuffs. The structural nature, nomenclature, and distribution of C-glycosyl flavonoids in the human diet are, therefore, reviewed. Forty-three dietary flavonoids are revealed to be C-glycosylated, arising from the dihydrochalcone, flavone, and flavan-3-ol backbones, and distributed among edible fruits, cereals, leaves, and stems. C-linked sugar groups are shown to include arabinose, galactose, glucose, rutinose, and xylose, often being present more than once on a single flavonoid backbone and occasionally in tandem with O-linked glucose or rutinose groups. The pharmacokinetic fate of these compounds is discussed with particular reference to their apparent lack of interaction with hydrolytic mechanisms known to influence the fate of O-glycosylated dietary flavonoids, explaining the unusual but potentially important appearance of intact C-glycosylated flavonoid metabolites in human urine following oral administration. Finally, the potential biological significance of these compounds is reviewed, describing mechanisms of antidiabetic, antiinflammatory, anxiolytic, antispasmodic, and hepatoprotective effects. PMID:24915338

  10. Application of SPARROW modeling to understanding contaminant fate and transport from uplands to streams

    Science.gov (United States)

    Ator, Scott; Garcia, Ana Maria.

    2016-01-01

    Understanding spatial variability in contaminant fate and transport is critical to efficient regional water-quality restoration. An approach to capitalize on previously calibrated spatially referenced regression (SPARROW) models to improve the understanding of contaminant fate and transport was developed and applied to the case of nitrogen in the 166,000 km2 Chesapeake Bay watershed. A continuous function of four hydrogeologic, soil, and other landscape properties significant (α = 0.10) to nitrogen transport from uplands to streams was evaluated and compared among each of the more than 80,000 individual catchments (mean area, 2.1 km2) in the watershed. Budgets (including inputs, losses or net change in storage in uplands and stream corridors, and delivery to tidal waters) were also estimated for nitrogen applied to these catchments from selected upland sources. Most (81%) of such inputs are removed, retained, or otherwise processed in uplands rather than transported to surface waters. Combining SPARROW results with previous budget estimates suggests 55% of this processing is attributable to denitrification, 23% to crop or timber harvest, and 6% to volatilization. Remaining upland inputs represent a net annual increase in landscape storage in soils or biomass exceeding 10 kg per hectare in some areas. Such insights are important for planning watershed restoration and for improving future watershed models.

  11. The influence of bedrock hydrogeology on catchment-scale nitrate fate and transport in fractured aquifers.

    Science.gov (United States)

    Orr, Alison; Nitsche, Janka; Archbold, Marie; Deakin, Jenny; Ofterdinger, Ulrich; Flynn, Raymond

    2016-11-01

    Characterising catchment scale biogeochemical processes controlling nitrate fate in groundwater constitutes a fundamental consideration when applying programmes of measures to reduce risks posed by diffuse agricultural pollutants to water quality. Combining hydrochemical analyses with nitrate isotopic data and physical hydrogeological measurements permitted characterisation of biogeochemical processes influencing nitrogen fate and transport in the groundwater in two fractured bedrock aquifers with contrasting hydrogeology but comparable nutrient loads. Hydrochemical and isotopic analyses of groundwater samples collected from moderately fractured, diffusely karstified limestone indicated nitrification controlled dissolved nitrogen fate and delivery to aquatic receptors. By contrast nitrate concentrations in groundwater were considerably lower in a low transmissivity highly lithified sandstone and pyrite-bearing shale unit with patchy subsoil cover. Geophysical and hydrochemical investigations showed shallower intervals contained hydraulically active fractures where denitrification was reflected through lower nitrogen levels and an isotopic enrichment ratio of 1.7 between δ(15)N and δ(18)O. Study findings highlight the influence of bedrock hydrogeological conditions on aqueous nitrogen mobility. Investigation results demonstrate that bedrock conditions need to be considered when implementing catchment management plans to reduce the impact of agricultural practices on the quality of groundwater and baseflow in receiving rivers. Nitrate isotopic signatures in the groundwater of a freely draining catchment underlain by a karstified aquifer and a poorly draining aquifer with a low transmissivity aquifer. PMID:27432726

  12. MODELING THE FATE AND TRANSPORT OF HYDROPHOBIC ORGANIC COMPOUNDS IN AN UNSTEADY RIVER-ESTUARINE SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Su-Chin CHEN; Jan-Tai KUO

    2002-01-01

    This research develops a generalized,one-dimensional,finite difference model for simulating the distribution of toxic substances in a river-estuarine system. The three sub-models for unsteady flow,sediment transport,and the reaction of toxic substances are also presented using an uncoupled numerical method. The paper also includes experimental work for sorption/desorption,field measurements of organic carbon content in the heavily polluted Keelung River,and a laboratory study of cohesive sediment transport for the model calibration and verification. In addition,this study simulates the polycyclic aromatic hydrocarbons (PAHs) in the Keelung River in northern Taiwan as a case study. Encouraging results are obtained,and suggest that the modeling approach could be extended to simulate the fate and transport of sorbed pollutants in tidal river.

  13. Evaluate and characterize mechanisms controlling transport, fate, and effects of army smokes in the aerosol wind tunnel: Transport, transformations, fate, and terrestrial ecological effects of hexachloroethane obscurant smokes

    Energy Technology Data Exchange (ETDEWEB)

    Cataldo, D.A.; Ligotke, M.W.; Bolton, H. Jr.; Fellows, R.J.; Van Voris, P.; McVeety, B.D.; Li, Shu-mei W.; McFadden, K.M.

    1989-09-01

    The terrestrial transport, chemical fate, and ecological effects of hexachloroethane (HC) smoke were evaluated under controlled wind tunnel conditions. The primary objectives of this research program are to characterize and assess the impacts of smoke and obscurants on: (1) natural vegetation characteristic of US Army training sites in the United States; (2) physical and chemical properties of soils representative of these training sites; and (3) soil microbiological and invertebrate communities. Impacts and dose/responses were evaluated based on exposure scenarios, including exposure duration, exposure rate, and sequential cumulative dosing. Key to understanding the environmental impacts of HC smoke/obscurants is establishing the importance of environmental parameters such as relative humidity and wind speed on airborne aerosol characteristics and deposition to receptor surfaces. Direct and indirect biotic effects were evaluated using five plant species and two soil types. HC aerosols were generated in a controlled atmosphere wind tunnel by combustion of hexachloroethane mixtures prepared to simulate normal pot burn rates and conditions. The aerosol was characterized and used to expose plant, soil, and other test systems. Particle sizes of airborne HC ranged from 1.3 to 2.1 {mu}m mass median aerodynamic diameter (MMAD), and particle size was affected by relative humidity over a range of 20% to 85%. Air concentrations employed ranged from 130 to 680 mg/m{sup 3}, depending on exposure scenario. Chlorocarbon concentrations within smokes, deposition rates for plant and soil surfaces, and persistence were determined. The fate of principal inorganic species (Zn, Al, and Cl) in a range of soils was assessed.

  14. Simulation of the environmental fate and transport of chemical signatures from buried landmines

    Energy Technology Data Exchange (ETDEWEB)

    Phelan, J.M.; Webb, S.W.

    1998-03-01

    The fate and transport of chemical signature molecules that emanate from buried landmines is strongly influenced by physical chemical properties and by environmental conditions of the specific chemical compounds. Published data have been evaluated as the input parameters that are used in the simulation of the fate and transport processes. A one-dimensional model developed for screening agricultural pesticides was modified and used to simulate the appearance of a surface flux above a buried landmine and estimate the subsurface total concentration. The physical chemical properties of TNT cause a majority of the mass released to the soil system to be bound to the solid phase soil particles. The majority of the transport occurs in the liquid phase with diffusion and evaporation driven advection of soil water as the primary mechanisms for the flux to the ground surface. The simulations provided herein should only be used for initial conceptual designs of chemical pre-concentration subsystems or complete detection systems. The physical processes modeled required necessary simplifying assumptions to allow for analytical solutions. Emerging numerical simulation tools will soon be available that should provide more realistic estimates that can be used to predict the success of landmine chemical detection surveys based on knowledge of the chemical and soil properties, and environmental conditions where the mines are buried. Additional measurements of the chemical properties in soils are also needed before a fully predictive approach can be confidently applied.

  15. A CASE STUDY OF CHLORINE TRANSPORT AND FATE FOLLOWING A LARGE ACCIDENTAL RELEASE

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, R.; Hunter, C.; Werth, D.; Whiteside, M.; Chen, K.; Mazzola, C.

    2012-08-01

    A train derailment that occurred in Graniteville, South Carolina during the early morning hours of 06 January, 2005 resulted in the prompt release of approximately 60 tons of chlorine to the environment. Comprehensive modeling of the transport and fate of this release was performed including the characterization of the initial three-phased chlorine release, a detailed determination of the local atmospheric conditions acting to generate, disperse, and deplete the chlorine vapor cloud, the establishment of physical exchange mechanisms between the airborne vapor and local surface waters, and local aquatic dilution and mixing.

  16. Complex Systems Science for Subsurface Fate and Transport Report from the August 2009 Workshop

    International Nuclear Information System (INIS)

    modeling and is defined, in the context of Biological Systems Science research programs under DOE's Office of Biological and Environmental Research (BER), as ''the holistic, multidisciplinary study of complex interactions that specify the function of an entire biological system - whether single cells or a multicellular organism - rather than the reductionist study of individual components.'' In August 2009, BER held the Subsurface Complex System Science Relevant to Contaminant Fate and Transport workshop to assess the merits and limitations of complex systems science approaches to subsurface systems controlled by coupled hydrological, microbiological, and geochemical processes.

  17. Overview of research and development in subsurface fate and transport modeling

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, T.M. [Brookhaven National Lab., Upton, NY (United States); Chehata, M. [Science Applications Internationa Corp. (United States)

    1995-05-01

    The US Department of Energy is responsible for the remediation of over 450 different subsurface-contaminated sites. Contaminant plumes at these sites range in volume from several to millions of cubic yards. The concentration of contaminants also ranges over several orders of magnitude. Contaminants include hazardous wastes such as heavy metals and organic chemicals, radioactive waste including tritium, uranium, and thorium, and mixed waste, which is a combination of hazardous and radioactive wastes. The physical form of the contaminants includes solutes, nonaqueous phase liquids (NAPLs), and vapor phase contaminants such as volatilized organic chemicals and radon. The subject of contaminant fate and transport modeling is multi-disciplinary, involving hydrology, geology, microbiology, chemistry, applied mathematics, computer science, and other areas of expertise. It is an issue of great significance in the United States and around the world. As such, many organizations have substantial programs in this area. In gathering data to prepare this report, a survey was performed of research and development work that is funded by US government agencies to improve the understanding and mechanistic modeling of processes that control contaminant movement through subsurface systems. Government agencies which fund programs that contain fate and transport modeling components include the Environmental Protection Agency, Nuclear Regulatory Commission, Department of Agriculture, Department of Energy, National Science Foundation, Department of Defense, United States Geological Survey, and National Institutes of Health.

  18. Overview of research and development in subsurface fate and transport modeling

    International Nuclear Information System (INIS)

    The US Department of Energy is responsible for the remediation of over 450 different subsurface-contaminated sites. Contaminant plumes at these sites range in volume from several to millions of cubic yards. The concentration of contaminants also ranges over several orders of magnitude. Contaminants include hazardous wastes such as heavy metals and organic chemicals, radioactive waste including tritium, uranium, and thorium, and mixed waste, which is a combination of hazardous and radioactive wastes. The physical form of the contaminants includes solutes, nonaqueous phase liquids (NAPLs), and vapor phase contaminants such as volatilized organic chemicals and radon. The subject of contaminant fate and transport modeling is multi-disciplinary, involving hydrology, geology, microbiology, chemistry, applied mathematics, computer science, and other areas of expertise. It is an issue of great significance in the United States and around the world. As such, many organizations have substantial programs in this area. In gathering data to prepare this report, a survey was performed of research and development work that is funded by US government agencies to improve the understanding and mechanistic modeling of processes that control contaminant movement through subsurface systems. Government agencies which fund programs that contain fate and transport modeling components include the Environmental Protection Agency, Nuclear Regulatory Commission, Department of Agriculture, Department of Energy, National Science Foundation, Department of Defense, United States Geological Survey, and National Institutes of Health

  19. Understanding the fate and biological effects of Ag- and TiO2-nanoparticles in the environment: The quest for advanced analytics and interdisciplinary concepts

    International Nuclear Information System (INIS)

    Engineered inorganic nanoparticles (EINP) from consumers' products and industrial applications, especially silver and titanium dioxide nanoparticles (NP), are emitted into the aquatic and terrestrial environments in increasing amounts. However, the current knowledge on their environmental fate and biological effects is diverse and renders reliable predictions complicated. This review critically evaluates existing knowledge on colloidal aging mechanisms, biological functioning and transport of Ag NP and TiO2 NP in water and soil and it discusses challenges for concepts, experimental approaches and analytical methods in order to obtain a comprehensive understanding of the processes linking NP fate and effects. Ag NP undergo dissolution and oxidation with Ag2S as a thermodynamically determined endpoint. Nonetheless, Ag NP also undergo colloidal transformations in the nanoparticulate state and may act as carriers for other substances. Ag NP and TiO2 NP can have adverse biological effects on organisms. Whereas Ag NP reveal higher colloidal stability and mobility, the efficiency of NOM as a stabilizing agent is greater towards TiO2 NP than towards Ag NP, and multivalent cations can dominate the colloidal behavior over NOM. Many of the past analytical obstacles have been overcome just recently. Single particle ICP-MS based methods in combination with field flow fractionation techniques and hydrodynamic chromatography have the potential to fill the gaps currently hampering a comprehensive understanding of fate and effects also at a low field relevant concentrations. These analytical developments will allow for mechanistically orientated research and transfer to a larger set of EINP. This includes separating processes driven by NP specific properties and bulk chemical properties, categorization of effect-triggering pathways directing the EINP effects towards specific recipients, and identification of dominant environmental parameters triggering fate and effect of EINP

  20. Understanding the fate and biological effects of Ag- and TiO{sub 2}-nanoparticles in the environment: The quest for advanced analytics and interdisciplinary concepts

    Energy Technology Data Exchange (ETDEWEB)

    Schaumann, Gabriele E., E-mail: schaumann@uni-landau.de [Universität Koblenz-Landau, Institute for Environmental Sciences, Group of Environmental and Soil Chemistry, Fortstr. 7, D-76829 Landau (Germany); Philippe, Allan, E-mail: philippe@uni-landau.de [Universität Koblenz-Landau, Institute for Environmental Sciences, Group of Environmental and Soil Chemistry, Fortstr. 7, D-76829 Landau (Germany); Bundschuh, Mirco, E-mail: mirco.bundschuh@slu.se [Universität Koblenz-Landau, Institute for Environmental Sciences, Group of Ecotoxicology and Environment, Fortstr. 7, D-76829 Landau (Germany); Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment, Lennart Hjelms väg 9, SE-75007 Uppsala (Sweden); Metreveli, George, E-mail: metreveli@uni-landau.de [Universität Koblenz-Landau, Institute for Environmental Sciences, Group of Environmental and Soil Chemistry, Fortstr. 7, D-76829 Landau (Germany); Klitzke, Sondra, E-mail: sondra.klitzke@tu-berlin.de [Albert-Ludwigs-Universität Freiburg, Institute of Forest Sciences, Chair of Soil Ecology, 79085 Freiburg i.Br. (Germany); Berlin University of Technology, Institute of Ecology, Department of Soil Science, Ernst-Reuter-Platz 1, D-10587 Berlin (Germany); Rakcheev, Denis, E-mail: rakcheev@uni-landau.de [Universität Koblenz-Landau, Institute for Environmental Sciences, Group of Environmental and Soil Chemistry, Fortstr. 7, D-76829 Landau (Germany); Grün, Alexandra, E-mail: alexg@uni-koblenz.de [Universität Koblenz-Landau, Institute for Integrated Natural Sciences, Dept. of Biology, Universitätsstr. 1, D-56070 Koblenz (Germany); and others

    2015-12-01

    Engineered inorganic nanoparticles (EINP) from consumers' products and industrial applications, especially silver and titanium dioxide nanoparticles (NP), are emitted into the aquatic and terrestrial environments in increasing amounts. However, the current knowledge on their environmental fate and biological effects is diverse and renders reliable predictions complicated. This review critically evaluates existing knowledge on colloidal aging mechanisms, biological functioning and transport of Ag NP and TiO{sub 2} NP in water and soil and it discusses challenges for concepts, experimental approaches and analytical methods in order to obtain a comprehensive understanding of the processes linking NP fate and effects. Ag NP undergo dissolution and oxidation with Ag{sub 2}S as a thermodynamically determined endpoint. Nonetheless, Ag NP also undergo colloidal transformations in the nanoparticulate state and may act as carriers for other substances. Ag NP and TiO{sub 2} NP can have adverse biological effects on organisms. Whereas Ag NP reveal higher colloidal stability and mobility, the efficiency of NOM as a stabilizing agent is greater towards TiO{sub 2} NP than towards Ag NP, and multivalent cations can dominate the colloidal behavior over NOM. Many of the past analytical obstacles have been overcome just recently. Single particle ICP-MS based methods in combination with field flow fractionation techniques and hydrodynamic chromatography have the potential to fill the gaps currently hampering a comprehensive understanding of fate and effects also at a low field relevant concentrations. These analytical developments will allow for mechanistically orientated research and transfer to a larger set of EINP. This includes separating processes driven by NP specific properties and bulk chemical properties, categorization of effect-triggering pathways directing the EINP effects towards specific recipients, and identification of dominant environmental parameters triggering

  1. Stochastic transport processes in discrete biological systems

    CERN Document Server

    Frehland, Eckart

    1982-01-01

    These notes are in part based on a course for advanced students in the applications of stochastic processes held in 1978 at the University of Konstanz. These notes contain the results of re­ cent studies on the stochastic description of ion transport through biological membranes. In particular, they serve as an introduction to an unified theory of fluctuations in complex biological transport systems. We emphasize that the subject of this volume is not to introduce the mathematics of stochastic processes but to present a field of theoretical biophysics in which stochastic methods are important. In the last years the study of membrane noise has become an important method in biophysics. Valuable information on the ion transport mechanisms in membranes can be obtained from noise analysis. A number of different processes such as the opening and closing of ion channels have been shown to be sources of the measured current or voltage fluctuations. Bio­ logical 'transport systems can be complex. For example, the tr...

  2. The effects of surface aging on nanoparticle fate and transport in natural and engineered porous media

    Science.gov (United States)

    Mittelman, Anjuliee M.

    Nanomaterials will be subjected to various surface transformations in the environment and within water and wastewater treatment systems. A comprehensive understanding of the fate and transport behavior of "aged" nanomaterials in both natural and engineered porous media is required in order to accurately quantify ecological and human health risks. This research sought to (1) evaluate the impact of ultraviolet (UV) light aging on nanoparticle transport in water-saturated porous media; and (2) assess the effects of influent water quality on silver nanoparticle retention and dissolution in ceramic water filters. Additionally, the value of quartz crystal microbalance (QCM-D) data in nanoparticle fate and transport studies was evaluated by comparing deposition behavior in complementary QCM-D and sand columns experiments. Silver (nAg) and iron oxide nanoparticles exposed to UV light were up to 50% more strongly retained in porous media compared with freshly prepared suspensions due to less negative surface charge and larger aggregate sizes. UV-aged nAg were more prone to dissolution in sand columns, resulting in effluent Ag+ concentrations as high as 1.2 mg/L. In ceramic water filters, dissolution and cation exchange processes controlled silver release into treated water. The use of acidic, high salinity, or high hardness water accelerated oxidative dissolution of the silver coating and resulted in effluent silver concentrations 5-10 times above international drinking water guidelines. Results support the recommendation for a regular filter replacement or silver re-application schedule to ensure ongoing efficacy. Taken in concert, these research findings suggest that oxidative aging of nanomaterial surfaces (either through exposure to UV light or aggressive water chemistries) will alter the fate of nanomaterials in the environment and may decrease the effective lifetime of devices which utilize nanotechnology. Corresponding QCM-D and column experiments revealed that

  3. Atmospheric fate and transport of fine volcanic ash: Does particle shape matter?

    Science.gov (United States)

    White, C. M.; Allard, M. P.; Klewicki, J.; Proussevitch, A. A.; Mulukutla, G.; Genareau, K.; Sahagian, D. L.

    2013-12-01

    Volcanic ash presents hazards to infrastructure, agriculture, and human and animal health. In particular, given the economic importance of intercontinental aviation, understanding how long ash is suspended in the atmosphere, and how far it is transported has taken on greater importance. Airborne ash abrades the exteriors of aircraft, enters modern jet engines and melts while coating interior engine parts causing damage and potential failure. The time fine ash stays in the atmosphere depends on its terminal velocity. Existing models of ash terminal velocities are based on smooth, quasi-spherical particles characterized by Stokes velocity. Ash particles, however, violate the various assumptions upon which Stokes flow and associated models are based. Ash particles are non-spherical and can have complex surface and internal structure. This suggests that particle shape may be one reason that models fail to accurately predict removal rates of fine particles from volcanic ash clouds. The present research seeks to better parameterize predictive models for ash particle terminal velocities, diffusivity, and dispersion in the atmospheric boundary layer. The fundamental hypothesis being tested is that particle shape irreducibly impacts the fate and transport properties of fine volcanic ash. Pilot studies, incorporating modeling and experiments, are being conducted to test this hypothesis. Specifically, a statistical model has been developed that can account for actual volcanic ash size distributions, complex ash particle geometry, and geometry variability. Experimental results are used to systematically validate and improve the model. The experiments are being conducted at the Flow Physics Facility (FPF) at UNH. Terminal velocities and dispersion properties of fine ash are characterized using still air drop experiments in an unconstrained open space using a homogenized mix of source particles. Dispersion and sedimentation dynamics are quantified using particle image

  4. 3D modelling of the transport and fate of riverine fine sediment exported to a semi-enclosed system

    Science.gov (United States)

    Delandmeter, Philippe; Lambrechts, Jonathan; Lewis, Stephen; Legat, Vincent; Deleersnijder, Eric; Wolanski, Eric

    2015-04-01

    Understanding the transport and fate of suspended sediment exported by rivers is crucial for the management of sensitive marine ecosystems. Sediment transport and fate can vary considerably depending on the geophysical characteristics of the offshore environment (i.e. open, semi-enclosed and enclosed systems and the nature of the continental shelf). In this presentation, we focus on a semi-enclosed setting in the Great Barrier Reef, NE Australia. In this system, the large tropical Burdekin River discharges to a long and narrow continental shelf containing numerous headlands and embayments. Using a new 3D sediment model we developed and SLIM 3D, a Finite Element 3D model for coastal flows, we highlight the key processes of sediment transport for such a system. We validate the model with available measured data from the region. Wind direction and speed during the high river flows are showed to largely control the dynamics and final fate of the sediments. Most (71%) of the sediment load delivered by the river is deposited and retained near the river mouth. The remaining sediment is transported further afield in riverine freshwater plumes. The suspended sediment transported longer distances in the freshwater plumes can reach sensitive marine ecosystems. These results are compared to previous studies on the Burdekin River sediment fate and differences are analysed. The model suggests that wind-driven resuspension events will redistribute sediments within an embayment but have little influence on transporting sediments from bay to bay.

  5. Denatured ethanol release into gasoline residuals, Part 2: Fate and transport

    Science.gov (United States)

    Freitas, Juliana G.; Barker, James F.

    2013-05-01

    When denatured ethanol (E95) is spilled in a site with previous gasoline contamination, it modifies the source distribution (Part 1). But it can also impact the transport and fate of hydrocarbons in the groundwater. Ethanol could cause an increase in dissolved concentrations and more persistent plumes due to cosolvency and decreased hydrocarbon biodegradation rates. To investigate these possibilities, two controlled releases were performed: first of E10 (gasoline with 10% ethanol) and one year later of E95 on top of the gasoline. Groundwater concentrations were monitored above and below the water table in multilevel wells. Soil cores and vapor samples were also collected over a period of approximately 400 days. Surprisingly, ethanol transport was very limited; at wells located 2.3 m downgradient from the mid-point of the release trench, the maximum concentration measured was around 2400 mg/L. After 392 days, only 3% of the ethanol released migrated past 2.3 m, and no ethanol remained in the source. The processes that caused ethanol loss were likely volatilization, aerobic biodegradation in the unsaturated zone, and anaerobic biodegradation. Evidence that biodegradation was significant in the source zone includes increased CO2 concentrations in the vapor and the presence of biodegradation products (acetate concentrations up to 2300 mg/L). The position of the dissolved hydrocarbon plumes was slightly shifted, but the concentrations and mass flux remained within the same range as before the spill, indicating that cosolvency was not significant. Hydrocarbons in the groundwater were significantly biodegraded, with more than 63% of the mass being removed in 7.5 m, even when ethanol was present in the groundwater. The impacts of ethanol on the hydrocarbon transport and fate were minimal, largely due to the separation of ethanol and hydrocarbons in the source (Part 1).

  6. Assessment of Contaminated Brine Fate and Transport in MB139 at WIPP

    Energy Technology Data Exchange (ETDEWEB)

    Kuhlman, Kristopher L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Applied Systems Analysis and Research Dept.; Malama, Bwalya [Sandia National Lab., Carlsbad, NM (United States). Performance Assessment Dept.

    2014-07-01

    Following the radionuclide release event of February 14, 2014 at the Waste Isolation Pilot Plant (WIPP), actinide contamination has been found on the walls and floor in Panel 7 as a result of a release in Room 7 of Panel 7. It has been proposed to decontaminate Panel 7 at the WIPP by washing contaminated surfaces in the underground with fresh water. A cost-effective cleanup of this contamination would allow for a timely return to waste disposal operations at WIPP. It is expected that the fresh water used to decontaminate Panel 7 will flow as contaminated brine down into the porosity of the materials under the floor – the run-of-mine (ROM) salt above Marker Bed 139 (MB139) and MB139 itself – where its fate will be controlled by the hydraulic and transport properties of MB139. Due to the structural dip of MB139, it is unlikely that this brine would migrate northward towards the Waste-Handling Shaft sump. A few strategically placed shallow small-diameter observation boreholes straddling MB139 would allow for monitoring the flow and fate of this brine after decontamination. Additionally, given that flow through the compacted ROM salt floor and in MB139 would occur under unsaturated (or two-phase) conditions, there is a need to measure the unsaturated flow properties of crushed WIPP salt and salt from the disturbed rock zone (DRZ).

  7. Assessment of Contaminated Brine Fate and Transport in MB139 at WIPP

    Energy Technology Data Exchange (ETDEWEB)

    Kuhlman, Kristopher L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Applied Systems Analysis and Research Dept.; Malama, Bwalya [Sandia National Lab., Carlsbad, NM (United States). Performance Assessment Dept.

    2014-07-01

    Following the radionuclide release event of February 14, 2014 at the Waste Isolation Pilot Plant (WIPP), actinide contamination has been found on the walls and floor in Panel 7 as a result of a release in Room 7 of Panel 7. It has been proposed to decontaminate Panel 7 at the WIPP by washing contaminated surfaces in the underground with fresh water (Nelson, 2014a). A cost-effective cleanup of this contamination would allow for a timely return to waste disposal operations at WIPP. It is expected that the fresh water used to decontaminate Panel 7 will flow as contaminated brine down into the porosity of the materials under the floor – the run-of-mine (ROM) salt above Marker Bed 139 (MB139) and MB139 itself – where its fate will be controlled by the hydraulic and transport properties of MB139. Due to the structural dip of MB139, it is unlikely that this brine would migrate northward towards the Waste-Handling Shaft sump. A few strategically placed shallow small-diameter observation boreholes straddling MB139 would allow for monitoring the flow and fate of this brine after decontamination. Additionally, given that flow through the compacted ROM salt floor and in MB139 would occur under unsaturated (or two-phase) conditions, there is a need to measure the unsaturated flow properties of crushed WIPP salt and salt from the disturbed rock zone (DRZ).

  8. Fate and transport processes controlling the migration of hazardous and radioactive materials from the Area 5 Radioactive Waste Management Site (RWMS)

    International Nuclear Information System (INIS)

    Desert vadose zones have been considered as suitable environments for the safe and long-term isolation of hazardous wastes. Low precipitation, high evapotranspiration and thick unsaturated alluvial deposits commonly found in deserts make them attractive as waste disposal sites. The fate and transport of any contaminant in the subsurface is ultimately determined by the operating retention and transformation processes in the system and the end result of the interactions among them. Retention (sorption) and transformation are the two major processes that affect the amount of a contaminant present and available for transport. Retention processes do not affect the total amount of a contaminant in the soil system, but rather decrease or eliminate the amount available for transport at a given point in time. Sorption reactions retard the contaminant migration. Permanent binding of solute by the sorbent is also possible. These processes and their interactions are controlled by the nature of the hazardous waste, the properties of the porous media and the geochemical and environmental conditions (temperature, moisture and vegetation). The present study summarizes the available data and investigates the fate and transport processes that govern the migration of contaminants from the Radioactive Waste Management Site (RWMS) in Area 5 of the Nevada Test Site (NTS). While the site is currently used only for low-level radioactive waste disposal, past practices have included burial of material now considered hazardous. Fundamentals of chemical and biological transformation processes are discussed subsequently, followed by a discussion of relevant results

  9. Fate and transport processes controlling the migration of hazardous and radioactive materials from the Area 5 Radioactive Waste Management Site (RWMS)

    Energy Technology Data Exchange (ETDEWEB)

    Estrella, R.

    1994-10-01

    Desert vadose zones have been considered as suitable environments for the safe and long-term isolation of hazardous wastes. Low precipitation, high evapotranspiration and thick unsaturated alluvial deposits commonly found in deserts make them attractive as waste disposal sites. The fate and transport of any contaminant in the subsurface is ultimately determined by the operating retention and transformation processes in the system and the end result of the interactions among them. Retention (sorption) and transformation are the two major processes that affect the amount of a contaminant present and available for transport. Retention processes do not affect the total amount of a contaminant in the soil system, but rather decrease or eliminate the amount available for transport at a given point in time. Sorption reactions retard the contaminant migration. Permanent binding of solute by the sorbent is also possible. These processes and their interactions are controlled by the nature of the hazardous waste, the properties of the porous media and the geochemical and environmental conditions (temperature, moisture and vegetation). The present study summarizes the available data and investigates the fate and transport processes that govern the migration of contaminants from the Radioactive Waste Management Site (RWMS) in Area 5 of the Nevada Test Site (NTS). While the site is currently used only for low-level radioactive waste disposal, past practices have included burial of material now considered hazardous. Fundamentals of chemical and biological transformation processes are discussed subsequently, followed by a discussion of relevant results.

  10. Development of Probabilistic Fate and Transport Models for the Mixed Waste Landfill at Sandia National Laboratories

    International Nuclear Information System (INIS)

    A probabilistic performance assessment has been conducted to evaluate the fate and transport of radionuclides (Am-241, Cs-137, Co-60, Pu-238, Pu-239, Ra-226, Rn-222, Sr-90, Th-232, H-3, U-238), heavy metals (lead and cadmium), and volatile organic compounds at the Mixed Waste Landfill (MWL). Probabilistic analyses were performed to quantify uncertainties inherent in the system and models for a 1,000-year period, and sensitivity analyses were performed to identify parameters and processes that were most important to the simulated performance metrics. Comparisons between simulated results and measured values at the MWL were made to gain confidence in the models and perform calibrations when data were available. In addition, long-term monitoring requirements and triggers were recommended based on the results of the quantified uncertainty and sensitivity analyses. (authors)

  11. Modelling the fate and transport of faecal bacteria in estuarine and coastal waters.

    Science.gov (United States)

    Gao, Guanghai; Falconer, Roger A; Lin, Binliang

    2015-11-15

    This paper details a numerical model developed to predict the fate and transport of faecal bacteria in receiving surface waters. The model was first validated by comparing model predicted faecal bacteria concentrations with available field measurements. The model simulations agreed well with the observation data. After calibration, the model was applied to investigate the effects of different parameters, including: tidal processes, river discharges from the upstream boundaries and bacteria inputs from the upstream boundaries, wastewater treatment works (WwTWs), rivers and combined sewer overflows (CSO), on the concentrations of faecal bacteria in the Ribble Estuary. The results revealed that the tide and upstream boundary bacteria inputs were the primary factors controlling the distribution of faecal bacteria. The bacteria inputs from the WwTWs in the model domain were generally found not to have a significant impact on distribution of faecal bacteria in the estuary. PMID:26384864

  12. Modelling the fate and transport of faecal bacteria in estuarine and coastal waters.

    Science.gov (United States)

    Gao, Guanghai; Falconer, Roger A; Lin, Binliang

    2015-11-15

    This paper details a numerical model developed to predict the fate and transport of faecal bacteria in receiving surface waters. The model was first validated by comparing model predicted faecal bacteria concentrations with available field measurements. The model simulations agreed well with the observation data. After calibration, the model was applied to investigate the effects of different parameters, including: tidal processes, river discharges from the upstream boundaries and bacteria inputs from the upstream boundaries, wastewater treatment works (WwTWs), rivers and combined sewer overflows (CSO), on the concentrations of faecal bacteria in the Ribble Estuary. The results revealed that the tide and upstream boundary bacteria inputs were the primary factors controlling the distribution of faecal bacteria. The bacteria inputs from the WwTWs in the model domain were generally found not to have a significant impact on distribution of faecal bacteria in the estuary.

  13. Effect of nonionic surfactant Brij 35 on the fate and transport of oxytetracycline antibiotic in soil.

    Science.gov (United States)

    Elsayed, Eman M; Prasher, Shiv O; Patel, Ramanbhai M

    2013-02-15

    In many parts of the world, river water is used for irrigation. Treated, partially treated, and even untreated water from wastewater treatment plants is discharged directly into rivers, thereby degrading the quality of the water. Consequently, irrigation water may contain surfactants which may affect the fate and transport of chemicals such as pesticides and antibiotics in agricultural soils. A field lysimeter study was undertaken to investigate the effect of the nonionic surfactant, Brij 35, on the fate and transport of an antibiotic, Oxytetracycline, commonly used in cattle farms. Nine PVC lysimeters, 1.0 m long × 0.45 m diameter, were packed with a sandy soil to a bulk density of 1.35 Mg m(-3). Cattle manure, containing Oxytetracycline, was applied at the surface of the lysimeters at the recommended rate of 10 t/ha. Each of three aqueous Brij 35 solutions, 0, 0.5 and 5 g L(-1) (i.e., 'good,' 'poor' and 'very poor' quality irrigation water) were each applied to the lysimeters in triplicate. Over a 90 day period, soil and leachate samples were collected and analyzed. Batch experiment results showed that the presence of the nonionic surfactant Brij 35 significantly reduced the sorption coefficient of OTC from 23.55 mL g(-1) in the aqueous medium to 19.49, 12.49 and 14.53 in the presence of Brij 35 at concentrations of 0.25, 2.5 and 5 g L(-1), respectively. Lysimeter results indicted the significant downward movement of OTC at depths of 60 cm into soil profile and leachate in the presence of surfactant. Thus, the reuse of wastewater containing surfactants might enhance the mobility of contaminants and increase ground water pollution. PMID:23295679

  14. The Impacts of Different Meteorology Data Sets on Nitrogen Fate and Transport in the SWAT Watershed Model

    Science.gov (United States)

    In this study, we investigated how different meteorology data sets impacts nitrogen fate and transport responses in the Soil and Water Assessment Tool (SWAT) model. We used two meteorology data sets: National Climatic Data Center (observed) and Mesoscale Model 5/Weather Research ...

  15. Extending the BSM platform with occurrence, transport and fate of micro-pollutants using the ASM-X framework

    DEFF Research Database (Denmark)

    Flores-Alsina, Xavier; Plósz, Benedek; Lindblom, Erik;

    The objective of this paper is to demonstrate how occurrence, transport and fate of trace chemicals can be assessed when modelling wastewater treatment plants (WWTP). A modified version of the International Water Association (IWA) Benchmark Simulation Model No 1 (BSM1) used to evaluate control st...

  16. Howard Brenner's Legacy for Biological Transport Processes

    Science.gov (United States)

    Nitsche, Johannes

    2014-11-01

    This talk discusses the manner in which Howard Brenner's theoretical contributions have had, and long will have, strong and direct impact on the understanding of transport processes occurring in biological systems. His early work on low Reynolds number resistance/mobility coefficients of arbitrarily shaped particles, and particles near walls and in pores, is an essential component of models of hindered diffusion through many types of membranes and tissues, and convective transport in microfluidic diagnostic systems. His seminal contributions to macrotransport (coarse-graining, homogenization) theory presaged the growing discipline of multiscale modeling. For biological systems they represent the key to infusing diffusion models of a wide variety of tissues with a sound basis in their microscopic structure and properties, often over a hierarchy of scales. Both scientific currents are illustrated within the concrete context of diffusion models of drug/chemical diffusion through the skin. This area of theory, which is key to transdermal drug development and risk assessment of chemical exposure, has benefitted very directly from Brenner's contributions. In this as in other areas, Brenner's physicochemical insight, mathematical virtuosity, drive for fully justified analysis free of ad hoc assumptions, quest for generality, and impeccable exposition, have consistently elevated the level of theoretical understanding and presentation. We close with anecdotes showing how his personal qualities and warmth helped to impart high standards of rigor to generations of grateful research students. Authors are Johannes M. Nitsche, Ludwig C. Nitsche and Gerald B. Kasting.

  17. Complex Systems Science for Subsurface Fate and Transport Report from the August 2009 Workshop

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-03-01

    experimentation and modeling and is defined, in the context of Biological Systems Science research programs under DOE's Office of Biological and Environmental Research (BER), as ''the holistic, multidisciplinary study of complex interactions that specify the function of an entire biological system - whether single cells or a multicellular organism - rather than the reductionist study of individual components.'' In August 2009, BER held the Subsurface Complex System Science Relevant to Contaminant Fate and Transport workshop to assess the merits and limitations of complex systems science approaches to subsurface systems controlled by coupled hydrological, microbiological, and geochemical processes.

  18. Interdisciplinary Research to Elucidate Mechanisms Governing Silver Nanoparticle Fate and Transport in Porous Media

    Science.gov (United States)

    Pennell, K. D.; Mittleman, A.; Taghavy, A.; Fortner, J.; Lantagne, D.; Abriola, L. M.

    2015-12-01

    Interdisciplinary Research to Elucidate Mechanisms Governing Silver Nanoparticle Fate and Transport in Porous Media Anjuliee M. Mittelman, Amir Taghavy, Yonggang Wang, John D. Fortner, Daniele S. Lantagne, Linda M. Abriola and Kurt D. Pennell* Detailed knowledge of the processes governing nanoparticle transport and reactivity in porous media is essential for accurate predictions of environmental fate, water and wastewater treatment system performance, and assessment of potential risks to ecosystems and water supplies. To address these issues, an interdisciplinary research team combined experimental and mathematical modeling studies to investigate the mobility, dissolution, and aging of silver nanoparticles (nAg) in representative aquifer materials and ceramic filters. Results of one-dimensional column studies, conducted with water-saturated sands maintained at pH 4 or 7 and three levels of dissolved oxygen (DO), revealed that fraction of silver mass eluted as Ag+ increased with increasing DO level, and that the dissolution of attached nAg decreased over time as a result of surface oxidation. A hybrid Eulerain-Lagragian nanoparticle transport model, which incorporates DO-dependent dissolution kinetics and particle aging, was able to accurately simulate nAg mobility and Ag+ release measured in the column experiments. Model sensitivity analysis indicated that as the flow velocity and particle size decrease, nAg dissolution and Ag+ transport processes increasingly govern silver mobility. Consistent results were obtained in studies of ceramic water filters treated with nAg, where silver elution was shown to be governed by nAg dissolution to form Ag+ and subsequent cation exchange reactions. Recent studies explored the effects of surface coating aging on nAg aggregation, mobility and dissolution. Following ultraviolet light, nAg retention in water saturated sand increased by 25-50%, while up to 50% of the applied mass eluted as Ag+ compared to less than 1% for un-aged n

  19. Interdisciplinary Research to Elucidate Mechanisms Governing Silver Nanoparticle Fate and Transport in Porous Media

    Science.gov (United States)

    Pennell, K. D.; Mittleman, A.; Taghavy, A.; Fortner, J.; Lantagne, D.; Abriola, L. M.

    2014-12-01

    Interdisciplinary Research to Elucidate Mechanisms Governing Silver Nanoparticle Fate and Transport in Porous Media Anjuliee M. Mittelman, Amir Taghavy, Yonggang Wang, John D. Fortner, Daniele S. Lantagne, Linda M. Abriola and Kurt D. Pennell* Detailed knowledge of the processes governing nanoparticle transport and reactivity in porous media is essential for accurate predictions of environmental fate, water and wastewater treatment system performance, and assessment of potential risks to ecosystems and water supplies. To address these issues, an interdisciplinary research team combined experimental and mathematical modeling studies to investigate the mobility, dissolution, and aging of silver nanoparticles (nAg) in representative aquifer materials and ceramic filters. Results of one-dimensional column studies, conducted with water-saturated sands maintained at pH 4 or 7 and three levels of dissolved oxygen (DO), revealed that fraction of silver mass eluted as Ag+ increased with increasing DO level, and that the dissolution of attached nAg decreased over time as a result of surface oxidation. A hybrid Eulerain-Lagragian nanoparticle transport model, which incorporates DO-dependent dissolution kinetics and particle aging, was able to accurately simulate nAg mobility and Ag+ release measured in the column experiments. Model sensitivity analysis indicated that as the flow velocity and particle size decrease, nAg dissolution and Ag+ transport processes increasingly govern silver mobility. Consistent results were obtained in studies of ceramic water filters treated with nAg, where silver elution was shown to be governed by nAg dissolution to form Ag+ and subsequent cation exchange reactions. Recent studies explored the effects of surface coating aging on nAg aggregation, mobility and dissolution. Following ultraviolet light, nAg retention in water saturated sand increased by 25-50%, while up to 50% of the applied mass eluted as Ag+ compared to less than 1% for un-aged n

  20. Geochemical, hydrological and biological cycling of energy residuals. Research plan: subsurface transport program

    International Nuclear Information System (INIS)

    Because natural processes associated with the release and the transport of organic compounds, trace metals, and radionuclides are incompletely understood, research in this area is critical if the long term scientific uncertainties about contaminant transport are to be resolved. The processes that control mobilization and attenuation of energy residuals in soils and geological strata, their hydrological transport to and within ground water regimes, and their accumulation in biological systems require research attention. A summary of DOE's core research program is described. It is designed to provide a base of fundamental scientific information so that the geochemical hydrological, and biophysical mechanics that contribute to the transport and long term fate of energy related contaminants in natural systems can be understood

  1. Investigation and simulation on fate and transport of leachate from a livestock mortality burial site

    Science.gov (United States)

    Lim, J.-W.; Lee, S.; Kaown, D.; Lee, K.-K.

    2012-04-01

    Leachate released from livestock mortality burial during decomposition of carcasses can be a threat to groundwater quality. Monitoring study of groundwater quality in the vicinity of livestock burial reported that a caution is needed to prevent contamination of both groundwater and soil, especially in case of mortality burial (Glanville, 2000; Ritter and Chirnside, 1995). The average concentration of ammonium-N and chloride is reported to be 12,600 mg/l and 2,600 mg/l respectively, which is 2-4 times higher than leachate from earthen manure storages and landfills (Pratt, 2009). To assess the potential threat of burial leachate to groundwater quality, simulation of leachate transport is performed based on a hydrogeologic model of an actual mortality burial site. At the burial site of this study located at a hill slope, two mortality pits have been constructed along the slope to bury swine during the outbreak of nationwide foot and mouth disease(FMD) in 2011. Though the pits were partially lined with impermeable material, potential threat of leachate leakage is still in concern. Electrical resistivity survey has been performed several times at the burial site and abnormal resistivity zones have been detected which are supposed as leachate leakage from the burial. Subsurface model including unsaturated zone is built since the leakage is supposed to occur mainly in lateral of the burial pits which is in unsaturated zone. When examining leachate transport, main focus is given to a nitrogenous compound and colloidal character of FMD virus. Nitrifying of denitrifying characters of nitrogenous compound and transport of colloidal particles are affected mainly by soil water content in unsaturated zone. Thus, the fate and transport of burial leachate affected by seasonal variation in recharge pattern is investigated.

  2. Fate and transport of selected estrogen compounds in Hawaii soils: Effect of soil type and macropores

    Science.gov (United States)

    D'Alessio, Matteo; Vasudevan, Dharni; Lichwa, Joseph; Mohanty, Sanjay K.; Ray, Chittaranjan

    2014-10-01

    The fate and transport of estrogen compounds in the environment is of increasing concern due to their potential impact on freshwater organisms, ecosystems and human health. The behavior of these compounds in batch experiments suggests low mobility, while field studies indicate the persistence of estrogen compounds in the soil with the possibility of migration to surface water as well as groundwater. To better understand the movement of these chemicals through soils, we examined their transport in three different Hawaiian soils and two aqueous matrices. The three different soils used were an Oxisol, a Mollisol and a cinder, characterized by different mineralogical properties and collected at depths of 60-90 cm and 210-240 cm. Two liquid matrices were used; deionized (DI) water containing calcium chloride (CaCl2), and recycled water collected from a wastewater treatment facility. The experiments were conducted in packed and structured columns. Non-equilibrium conditions were observed during the study, especially in the structured soil. This is believed to be primarily related to the presence of macropores in the soil. The presence of macropores resulted in reduced contact time between soil and estrogens, which facilitated their transport. We found that the organic carbon content and mineralogical composition of the soils had a profound effect on the transport of the estrogens. The mobility of estrone (E1) and 17β-estradiol (E2) was greater in cinder than in the other soils. In column experiments with recycled water, earlier breakthrough peaks and longer tails of estrogens were produced compared to those observed using DI water. The use of recycled water for agricultural purposes and the siting of septic tanks and cesspools should be critically reviewed in light of these findings, especially in areas where groundwater is the primary source of potable water, such as Hawaii.

  3. Fate and transport of selected estrogen compounds in Hawaii soils: effect of soil type and macropores.

    Science.gov (United States)

    D'Alessio, Matteo; Vasudevan, Dharni; Lichwa, Joseph; Mohanty, Sanjay K; Ray, Chittaranjan

    2014-10-01

    The fate and transport of estrogen compounds in the environment is of increasing concern due to their potential impact on freshwater organisms, ecosystems and human health. The behavior of these compounds in batch experiments suggests low mobility, while field studies indicate the persistence of estrogen compounds in the soil with the possibility of migration to surface water as well as groundwater. To better understand the movement of these chemicals through soils, we examined their transport in three different Hawaiian soils and two aqueous matrices. The three different soils used were an Oxisol, a Mollisol and a cinder, characterized by different mineralogical properties and collected at depths of 60-90 cm and 210-240 cm. Two liquid matrices were used; deionized (DI) water containing calcium chloride (CaCl2), and recycled water collected from a wastewater treatment facility. The experiments were conducted in packed and structured columns. Non-equilibrium conditions were observed during the study, especially in the structured soil. This is believed to be primarily related to the presence of macropores in the soil. The presence of macropores resulted in reduced contact time between soil and estrogens, which facilitated their transport. We found that the organic carbon content and mineralogical composition of the soils had a profound effect on the transport of the estrogens. The mobility of estrone (E1) and 17β-estradiol (E2) was greater in cinder than in the other soils. In column experiments with recycled water, earlier breakthrough peaks and longer tails of estrogens were produced compared to those observed using DI water. The use of recycled water for agricultural purposes and the siting of septic tanks and cesspools should be critically reviewed in light of these findings, especially in areas where groundwater is the primary source of potable water, such as Hawaii.

  4. Hydrogeologic Processes Impacting Storage, Fate, and Transport of Chloride from Road Salt in Urban Riparian Aquifers.

    Science.gov (United States)

    Ledford, Sarah H; Lautz, Laura K; Stella, John C

    2016-05-17

    Detrimental effects of road salt runoff on urban streams are compounded by its facilitated routing via storm drains, ditches, and flood channels. Elevated in-stream salinity may also result from seasonal storage and discharge of chloride in groundwater, and previous work has hypothesized that groundwater discharge to streams may have the effect of diluting stream chloride concentrations in winter and enriching them in summer. However, the hydrogeological processes controlling these patterns have not been thoroughly investigated. Our research focuses on an urban stream and floodplain system in Syracuse, NY, to understand how groundwater and surface water exchange impacts chloride storage, fate, and transport. We created a 3D groundwater flow and solute transport model of the floodplain, calibrated to the distributions of floodplain hydraulic heads and groundwater fluxes to the stream throughout the reach. We used a sensitivity analysis to calibrate and evaluate the influence of model parameters, and compared model outputs to field observations. The main source mechanism of chloride to the floodplain aquifer was high-concentration, overbank flood events in winter that directly recharged groundwater. The modeled residence time and storage capacity of the aquifer indicate that restoration projects designed to promote floodplain reconnection and the frequency of overbank flooding in winter have the potential to temporarily store chloride in groundwater, buffer surface water concentrations, and reduce stream concentrations following periods of road salting.

  5. Hydrogeologic Processes Impacting Storage, Fate, and Transport of Chloride from Road Salt in Urban Riparian Aquifers.

    Science.gov (United States)

    Ledford, Sarah H; Lautz, Laura K; Stella, John C

    2016-05-17

    Detrimental effects of road salt runoff on urban streams are compounded by its facilitated routing via storm drains, ditches, and flood channels. Elevated in-stream salinity may also result from seasonal storage and discharge of chloride in groundwater, and previous work has hypothesized that groundwater discharge to streams may have the effect of diluting stream chloride concentrations in winter and enriching them in summer. However, the hydrogeological processes controlling these patterns have not been thoroughly investigated. Our research focuses on an urban stream and floodplain system in Syracuse, NY, to understand how groundwater and surface water exchange impacts chloride storage, fate, and transport. We created a 3D groundwater flow and solute transport model of the floodplain, calibrated to the distributions of floodplain hydraulic heads and groundwater fluxes to the stream throughout the reach. We used a sensitivity analysis to calibrate and evaluate the influence of model parameters, and compared model outputs to field observations. The main source mechanism of chloride to the floodplain aquifer was high-concentration, overbank flood events in winter that directly recharged groundwater. The modeled residence time and storage capacity of the aquifer indicate that restoration projects designed to promote floodplain reconnection and the frequency of overbank flooding in winter have the potential to temporarily store chloride in groundwater, buffer surface water concentrations, and reduce stream concentrations following periods of road salting. PMID:27077530

  6. A COMPREHENSIVE ANALYSIS OF CHLORINE TRANSPORT AND FATE FOLLOWING A LARGE ENVIRONMENTAL RELEASE

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, R.; Hunter, C.; Werth, D.; Chen, K.; Whiteside, M.; Mazzola, C.

    2011-05-10

    A train derailment occurred in Graniteville, South Carolina during the early morning of January 6, 2005, and resulted in the release of a large amount of cryogenic pressurized liquid chlorine to the environment in a short time period. A comprehensive evaluation of the transport and fate of the released chlorine was performed, accounting for dilution, diffusion, transport and deposition into the local environment. This involved the characterization of a three-phased chlorine release, a detailed determination of local atmospheric mechanisms acting on the released chlorine, the establishment of atmospheric-hydrological physical exchange mechanisms, and aquatic dilution and mixing. This presentation will provide an overview of the models used in determining the total air-to-water mass transfer estimated to have occurred as a result of the roughly 60 tons of chlorine released into the atmosphere from the train derailment. The assumptions used in the modeling effort will be addressed, along with a comparison with available observational data to validate the model results. Overall, model-estimated chlorine concentrations in the airborne plume compare well with human and animal exposure data collected in the days after the derailment.

  7. Transport, fate, and infectivity of Cryptosporidium parvum oocysts released from manure and leached through macroporous soil

    Science.gov (United States)

    Boyer, Douglas G.; Kuczynska, Ewa; Fayer, Ron

    2009-09-01

    A major mode of transmission of Cryptosporidium parvum, a widespread waterborne pathogen, is via contaminated drinking and recreational waters. Oocyst transport to surface water can occur by deposition of manure directly in the water or by wash off in surface runoff. Oocyst transport to groundwater is less straightforward and requires that the oocysts move through soil and bedrock to reach the water table. The purpose of this study was to determine the relative concentration and infectivity of C. parvum oocysts released from manure and leached through columns of undisturbed, macroporous karst soil. Modeling the fate of oocysts in this system over time can provide baseline data for evaluating real world events. Substantially more oocysts leached from undisturbed soil columns than disturbed soil columns. Oocyst survival studies using BALB/c neonatal suckling mice showed that about 85% of oocysts were infective at the beginning of leaching experiments. The oocyst infectivity decreased to about 20% after 12 weeks of leaching from soil columns maintained at 10°C. Cool (10°C) temperatures appear to increase survivability and maintain infectivity of many oocysts for 3 months or longer. Cool temperatures also appear to increase rates of release of oocysts from manure and leaching through soil. This study demonstrated that leaching is an important mechanism of oocyst transport in karst soils where infiltration capacities are high and long, continuous macropores exist. Karst groundwater systems might be especially vulnerable to contamination by leached oocysts, because of the prevalence of shallow soils and rapid groundwater movement. Oocysts leaching from soils into the epikarst could accumulate and remain viable for months until hydrological conditions are right for flushing the oocysts into the conduit flow system.

  8. Modeling Fate and Transport of Rotavirus in Surface Flow by Integrating WEPP and a Pathogen Transport Model

    Science.gov (United States)

    Bhattarai, R.; Kalita, P. K.; Davidson, P. C.; Kuhlenschmidt, M. S.

    2012-12-01

    More than 3.5 million people die each year from a water related diseases in this world. Every 20 seconds, a child dies from a water-related illness. Even in a developed country like the United States, there have been at least 1870 outbreaks associated with drinking water during the period of 1920 to 2002, causing 883,806 illnesses. Most of these outbreaks are resulted due to the presence of microbial pathogens in drinking water. Rotavirus infection has been recognized as the most common cause of diarrhea in young children throughout the world. Laboratory experiments conducted at the University of Illinois have demonstrated that recovery of rotavirus has been significantly affected by climatic and soil-surface conditions like slope, soil types, and ground cover. The objective of this study is to simulate the fate and transport of Rotavirus in overland and near-surface flow using a process-based model. In order to capture the dynamics of sediment-bound pathogens, the Water Erosion Prediction Project (WEPP) is coupled with the pathogen transport model. Transport of pathogens in overland flow can be simulated mathematically by including terms for the concentration of the pathogens in the liquid phase (in suspension or free-floating) and the solid phase (adsorbed to the fine solid particles like clay and silt). Advection, adsorption, and decay processes are considered. The mass balance equations are solved using numerical technique to predict spatial and temporal changes in pathogen concentrations in two phases. Outputs from WEPP simulations (flow velocity, depth, saturated conductivity and the soil particle fraction exiting in flow) are transferred as input for the pathogen transport model. Three soil types and three different surface cover conditions have been used in the experimental investigations. Results from these conditions have been used in calibrating and validating the simulation results. Bare surface conditions have produced very good agreement between

  9. Biodistribution, kinetics, and biological fate of SPION microbubbles in the rat

    Directory of Open Access Journals (Sweden)

    Barrefelt A

    2013-08-01

    Full Text Available Åsa Barrefelt,1,2,* Maryam Saghafian,2,* Raoul Kuiper,3 Fei Ye,4 Gabriella Egri,5 Moritz Klickermann,5 Torkel B Brismar,1 Peter Aspelin,1 Mamoun Muhammed,4 Lars Dähne,5 Moustapha Hassan2,6 1Department of Clinical Science, Intervention and Technology, Division of Medical Imaging and Technology, Karolinska Institutet, and Department of Radiology, Karolinska University Hospital-Huddinge, Stockholm, Sweden; 2Experimental Cancer Medicine, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden; 3Karolinska Institute Core Facility for Morphologic Phenotype Analysis, Clinical Research Center, Karolinska University Hospital-Huddinge, Stockholm, Sweden; 4Division of Functional Materials, Department of Materials and Nano Physics, Royal Institute of Technology, Stockholm, Sweden; 5Surflay Nanotec GmbH, Berlin, Germany; 6Clinical Research Center, Karolinska University Hospital-Huddinge, Stockholm, Sweden *These authors contributed equally to this work Background: In the present investigation, we studied the kinetics and biodistribution of a contrast agent consisting of poly(vinyl alcohol (PVA microbubbles containing superparamagnetic iron oxide (SPION trapped between the PVA layers (SPION microbubbles. Methods: The biological fate of SPION microbubbles was determined in Sprague-Dawley rats after intravenous administration. Biodistribution and elimination of the microbubbles were studied in rats using magnetic resonance imaging for a period of 6 weeks. The rats were sacrificed and perfusion-fixated at different time points. The magnetic resonance imaging results obtained were compared with histopathologic findings in different organs. Results: SPION microbubbles could be detected in the liver using magnetic resonance imaging as early as 10 minutes post injection. The maximum signal was detected between 24 hours and one week post injection. Histopathology showed the presence of clustered SPION microbubbles predominantly in the lungs from

  10. Groundwater Fate and Transport Modeling for Texarkana Wood Preserving Company Superfund Site, Texarkana, Texas

    Energy Technology Data Exchange (ETDEWEB)

    Arnett, Ronald Chester

    1999-08-01

    Fate and transport model results are presented for the Texarkana Wood Preserving Company (TWPC)superfund site. The conceptual model assumes two sources of contamination, specifically, the areas around the old and new process areas. Recent data show the presence of non-aqueous phase liquids (NAPL) in the aquifer that are also sources of dissolved contamination in the aquifer. A flow model was constructed and calibrated against measured hydraulic heads at permanent monitoring wells. Good matches were obtained between model simulated heads and most measured heads. An unexplained exception occurs at monitoring well MW-13 down gradient of the site beyond the measured contaminant plume where the model predicts heads that are more than 2 ft. lower than reported field measurements. Adjusting hydraulic parameters in the model could not account for this anomaly and still preserve the head matches at other wells. There is likely a moderate deficiency in the conceptual model or perhaps a data error. Other information such as substantial amounts of infiltrating surface water in the area or a correction in surveyed elevation would improve the flow model. A particle tracking model calculated a travel time from the new process area to the Day’s Creek discharge location on the order of 40 years. Travel times from the old process area to Day’s Creek were calculated to be on the order of 80 years. While these calculations are subject to some uncertainty, travel times of decades are indicated.

  11. Mercury Fate and Transport in Hunza River Watershed, Northern Areas, Pakistan

    Science.gov (United States)

    Biber, K.; Khan, S. D.; Shah, M. T.

    2012-12-01

    Due to the highly mobile nature of mercury, it is considered to be a global environmental pollutant that is being distributed in the atmosphere, lithosphere and hydrosphere. Mercury's biogeochemical transfer between different compartments in the environment is complex and not known thoroughly. However, the importance of fate and transport of mercury in surface waters must be recognized for the well-being of people who drink or consume fish from contaminated waters. Using mercury in pan amalgamation for the extraction of gold from stream deposits along Indus and Gilgit Rivers in Pakistan is being practiced for many decades. Pan amalgamation in the small-scale gold panning and extraction (GPE) activities are known to be releasing significant amount of mercury to the environment due to inappropriate smelting practices. Analysis of 1372 stream sediments along Indus, Gilgit and Hunza Rivers showed that riverbank sediments upstream of Hunza and Gilgit Rivers are highly contaminated with mercury. From a data range of 4 to 2200 ppb, a total of 24 anomalous sites (having a concentration of more than 100 ppb) have been identified. These anomalies showed comparable results with US gold mine dump samples from mine sites existed until 1970s. In June 2011, 37 surface water samples were collected from Hunza River and its tributaries. Sample collection, preservation, storage and analysis were done as per EPA 1631 method. Samples were analyzed in terms of dissolved and particulate bound mercury content in the water. In these samples dissolved mercury concentration range from 5.10 ppt to 25.25 ppt, whereas, particulate bound mercury concentration varies between 4.85 ppb to 154.62 ppb. Total suspended solids were measured for each sampling site, in addition, field parameters, such as electrical conductivity, pH and temperature were measured in situ. During the field trip, many GPE sites were observed. First-hand observational data of the panning, washing, mercury amalgamation and

  12. Physical factors affecting the transport and fate of colloids in saturated porous media

    Science.gov (United States)

    Bradford, Scott A.; Yates, Scott R.; Bettahar, Mehdi; Simunek, Jirka

    2002-12-01

    Saturated soil column experiments were conducted to explore the influence of colloid size and soil grain size distribution characteristics on the transport and fate of colloid particles in saturated porous media. Stable monodispersed colloids and porous media that are negatively charged were employed in these studies. Effluent colloid concentration curves and the final spatial distribution of retained colloids by the porous media were found to be highly dependent on the colloid size and soil grain size distribution. Relative peak effluent concentrations decreased and surface mass removal by the soil increased when the colloid size increased and the soil median grain size decreased. These observations were attributed to increased straining of the colloids; i.e., blocked pores act as dead ends for the colloids. When the colloid size is small relative to the soil pore sizes, straining becomes a less significant mechanism of colloid removal and attachment becomes more important. Mathematical modeling of the colloid transport experiments using traditional colloid attachment theory was conducted to highlight differences in colloid attachment and straining behavior and to identify parameter ranges that are applicable for attachment models. Simulated colloid effluent curves using fitted first-order attachment and detachment parameters were able to describe much of the effluent concentration data. The model was, however, less adequate at describing systems which exhibited a gradual approach to the peak effluent concentration and the spatial distribution of colloids when significant mass was retained in the soil. Current colloid filtration theory did not adequately predict the fitted first-order attachment coefficients, presumably due to straining in these systems.

  13. Fate, mass balance, and transport of phosphorus in the septic system drainfields.

    Science.gov (United States)

    Mechtensimer, Sara; Toor, Gurpal S

    2016-09-01

    Septic systems can be a potential source of phosphorus (P) in shallow groundwater. Our objective was to investigate the fate, mass balance, and transport of P in the drainfield of a drip-dispersal septic system. Drainfields were replicated in lysimeters (152.4 cm long, 91.4 cm wide, and 91.4 cm high). Leachate and effluent samples were collected over 67 events (n = 15 daily; n = 52 weekly flow-weighted) and analyzed for total P (TP), orthophosphate (PO4P), and other P (TP - PO4P). Mean TP was 15 mg L(-1) (84% PO4P; 16% other P) in the effluent and 0.16 mg L(-1) (47% PO4P, 53% other P) in the leachate. After one year, 46.8 g of TP was added with effluent and rainfall to each drainfield, of which, 95% in the drainfield. Effluent dispersal increased water extractable P (WEP) in the drainfield from 10 mg kg(-1). Using the P sorption maxima of sand (118 mg kg(-1)) and soil (260 mg kg(-1)), we estimated that ∼18% of the drainfield P sorption capacity was saturated after one year of effluent dispersal. We conclude that despite the low leaching potential of P dispersed with effluent in the first year of drainfield operation, a growing WEP pool in the drainfield and low P sorption capacity of Florida's sandy soils may have the potential to transport P to shallow groundwater in long-running septic systems. PMID:27288645

  14. A novel modeling tool with multi-stressor functionality for organic contaminant transport and fate in the Baltic Sea

    International Nuclear Information System (INIS)

    The coupled physical–biogeochemical model BALTSEM, previously used to assess nutrient/carbon cycles and eutrophication in the Baltic Sea, has been expanded to include algorithms for calculations of organic contaminant environmental transport and fate. This novel model version (BALTSEM-POP) is evaluated for polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and hexachlorobenzene (HCB) in Baltic Sea surface water and sediment. Modeled dissolved concentrations are usually within a factor of 2–4 of observed concentrations, however with larger deviations for furans. Calculated concentrations in particulate organic matter are less accurate (within factors of 1–700), likely due to errors in estimated pelagic biomass, particulate matter–water partitioning, and large natural variability in field data. Concentrations in sediments are usually predicted within a factor of 6. The good performance of the model illustrates its usefulness for exploration of contaminant fate in response to variations in nutrient input and climatic conditions in the Baltic Sea marine environment. - Highlights: • A new model for organic chemical transport and fate in the Baltic Sea is presented. • Physical and biogeochemical processes are linked to organic contaminant transport. • The model is evaluated for PCBs, HCB and PCDD/Fs. • The model can predict dissolved concentrations within a factor of ca 2–4. • Predictions for concentrations in particulate matter and sediment are less accurate

  15. A novel modeling tool with multi-stressor functionality for organic contaminant transport and fate in the Baltic Sea

    Energy Technology Data Exchange (ETDEWEB)

    Undeman, E., E-mail: emma.undeman@itm.su.se [Baltic Nest Institute, Baltic Sea Centre, Stockholm University, 10691 Stockholm (Sweden); Department of Applied Environmental Science, Stockholm University, 11418 Stockholm (Sweden); Gustafsson, E., E-mail: erik.gustafsson@su.se [Baltic Nest Institute, Baltic Sea Centre, Stockholm University, 10691 Stockholm (Sweden); Gustafsson, B.G., E-mail: bo.gustafsson@su.se [Baltic Nest Institute, Baltic Sea Centre, Stockholm University, 10691 Stockholm (Sweden)

    2014-11-01

    The coupled physical–biogeochemical model BALTSEM, previously used to assess nutrient/carbon cycles and eutrophication in the Baltic Sea, has been expanded to include algorithms for calculations of organic contaminant environmental transport and fate. This novel model version (BALTSEM-POP) is evaluated for polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and hexachlorobenzene (HCB) in Baltic Sea surface water and sediment. Modeled dissolved concentrations are usually within a factor of 2–4 of observed concentrations, however with larger deviations for furans. Calculated concentrations in particulate organic matter are less accurate (within factors of 1–700), likely due to errors in estimated pelagic biomass, particulate matter–water partitioning, and large natural variability in field data. Concentrations in sediments are usually predicted within a factor of 6. The good performance of the model illustrates its usefulness for exploration of contaminant fate in response to variations in nutrient input and climatic conditions in the Baltic Sea marine environment. - Highlights: • A new model for organic chemical transport and fate in the Baltic Sea is presented. • Physical and biogeochemical processes are linked to organic contaminant transport. • The model is evaluated for PCBs, HCB and PCDD/Fs. • The model can predict dissolved concentrations within a factor of ca 2–4. • Predictions for concentrations in particulate matter and sediment are less accurate.

  16. Uranium Fate and Transport Modeling, Guterl Specialty Steel Site, New York - 13545

    Energy Technology Data Exchange (ETDEWEB)

    Frederick, Bill [US Army Corps of Engineers, Buffalo District, Buffalo, NY (United States); Tandon, Vikas [Shaw Environmental and Infrastructure Group, Stoughton, MA (United States)

    2013-07-01

    The Former Guterl Specialty Steel Corporation Site (Guterl Site) is located 32 kilometers (20 miles) northeast of Buffalo, New York, in Lockport, Niagara County, New York. Between 1948 and 1952, up to 15,875 metric tons (35 million pounds) of natural uranium metal (U) were processed at the former Guterl Specialty Steel Corporation site in Lockport, New York. The resulting dust, thermal scale, mill shavings and associated land disposal contaminated both the facility and on-site soils. Uranium subsequently impacted groundwater and a fully developed plume exists below the site. Uranium transport from the site involves legacy on-site pickling fluid handling, the leaching of uranium from soil to groundwater, and the groundwater transport of dissolved uranium to the Erie Canal. Groundwater fate and transport modeling was performed to assess the transfer of dissolved uranium from the contaminated soils and buildings to groundwater and subsequently to the nearby Erie Canal. The modeling provides a tool to determine if the uranium contamination could potentially affect human receptors in the vicinity of the site. Groundwater underlying the site and in the surrounding area generally flows southeasterly towards the Erie Canal; locally, groundwater is not used as a drinking water resource. The risk to human health was evaluated outside the Guterl Site boundary from the possibility of impacted groundwater discharging to and mixing with the Erie Canal waters. This condition was evaluated because canal water is infrequently used as an emergency water supply for the City of Lockport via an intake located approximately 122 meters (m) (400 feet [ft]) southeast of the Guterl Site. Modeling was performed to assess whether mixing of groundwater with surface water in the Erie Canal could result in levels of uranium exceeding the U.S. Environmental Protection Agency (USEPA) established drinking water standard for total uranium; the Maximum Concentration Limit (MCL). Geotechnical test

  17. Fate and Transport of Methane Formed in the Active Layer of Alaskan Permafrost

    Science.gov (United States)

    Conrad, M. E.; Curtis, J. B.; Smith, L. J.; Bill, M.; Torn, M. S.

    2015-12-01

    Over the past 2 years a series of tracer tests designed to estimate rates of methane formation via acetoclastic methanogenesis in the active layer of permafrost soils were conducted at the Barrow Environmental Observatory (BEO) in northernmost Alaska. The tracer tests consisted of extracting 0.5 to 1.0 liters of soil water in gas-tight bags from different features of polygons at the BEO, followed by addition of a tracer cocktail including acetate with a 13C-labeled methyl group and D2O (as a conservative tracer) into the soil water and injection of the mixture back into the original extraction site. Samples were then taken at depths of 30 cm (just above the bottom of the active layer), 20 cm, 10 cm and surface flux to determine the fate of the 13C-labeled acetate. During 2014 (2015 results are pending) water, soil gas, and flux gas were sampled for 60 days following injection of the tracer solution. Those samples were analyzed for concentrations and isotopic compositions of CH4, DIC/CO2 and water. At one site (the trough of a low-centered polygon) the 13C acetate was completely converted to 13CH4 within the first 2 days. The signal persisted for throughout the entire monitoring period at the injection depth with little evidence of transport or oxidation in any of the other sampling depths. In the saturated center of the same polygon, the acetate was also rapidly converted to 13CH4, but water turnover caused the signal to rapidly dissipate. High δ13C CO2 in flux samples from the polygon center indicate oxidation of the 13CH4 in near-surface waters. Conversely, CH4 production in the center of an unsaturated, flat-centered polygon was relatively small 13CH4 and dissipated rapidly without any evidence of either 13CH4 transport to shallower levels or oxidation. At another site in the edge of that polygon no 13CH4 was produced, but significant 13CO2/DIC was observed indicating direct aerobic oxidation of the acetate was occurring at this site. These results suggest that

  18. A model library for dynamic transport and fate of micropollutants in integrated urban wastewater and stormwater systems

    DEFF Research Database (Denmark)

    Vezzaro, Luca; Benedetti, Lorenzo; Gevaert, Veerle;

    2014-01-01

    the elaboration of pollution control strategies (including both source control and treatment options) at the small spatial scale of urban areas. Existing and well-established water quality models for the different parts of the IUWS (e.g. ASM models) are extended by adding MP fate processes. These are...... modelled by using substance inherent properties, following an approach commonly used in large-scale MP multimedia fate and transport models. The chosen level of complexity ensures a low data requirement and minimizes the need for field measurements. Next to a synthesis of model applications, a didactic...... example is presented to illustrate the potential of the use of the developed model library for developing, evaluating and comparing strategies for reduction of MP emissions from urban areas....

  19. Environmental transport and fate of endocrine disruptors from non-potable reuse of municipal wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, B; Beller, H; Bartel, C M; Kane, S; Campbell, C; Grayson, A; Liu, N; Burastero, S

    2005-11-16

    This project was designed to investigate the important but virtually unstudied topic of the subsurface transport and fate of Endocrine Disrupting Compounds (EDCs) when treated wastewater is used for landscape irrigation (non-potable water reuse). Although potable water reuse was outside the scope of this project, the investigation clearly has relevance to such water recycling practices. The target compounds, which are discussed in the following section and include EDCs such as 4-nonylphenol (NP) and 17{beta}-estradiol, were studied not only because of their potential estrogenic effects on receptors but also because they can be useful as tracers of wastewater residue in groundwater. Since the compounds were expected to occur at very low (part per trillion) concentrations in groundwater, highly selective and sensitive analytical techniques had to be developed for their analysis. This project assessed the distributions of these compounds in wastewater effluents and groundwater, and examined their fate in laboratory soil columns simulating the infiltration of treated wastewater into an aquifer (e.g., as could occur during irrigation of a golf course or park with nonpotable treated water). Bioassays were used to determine the estrogenic activity present in effluents and groundwater, and the results were correlated with those from chemical analysis. In vitro assays for estrogenic activity were employed to provide an integrated measure of estrogenic potency of environmental samples without requiring knowledge or measurement of all bioactive compounds in the samples. For this project, the Las Positas Golf Course (LPGC) in the City of Livermore provided an ideal setting. Since 1978, irrigation of this area with treated wastewater has dominated the overall water budget. For a variety of reasons, a group of 10 monitoring wells were installed to evaluate wastewater impacts on the local groundwater. Additionally, these wells were regularly monitored for tritium ({sup 3}H

  20. Vadose Zone Contaminant Fate and Transport Analysis for the 216-B-26 Trench

    Energy Technology Data Exchange (ETDEWEB)

    Ward, Andy L.; Gee, Glendon W.; Zhang, Z. F.; Keller, Jason M.

    2004-10-14

    The BC Cribs and Trenches, part of the 200 TW 1 OU waste sites, received about 30 Mgal of scavenged tank waste, with possibly the largest inventory of 99Tc ever disposed to the soil at Hanford and site remediation is being accelerated. The purpose of this work was to develop a conceptual model for contaminant fate and transport at the 216-B-26 Trench site to support identification and development and evaluation of remediation alternatives. Large concentrations of 99Tc high above the water table implicated stratigraphy in the control of the downward migration. The current conceptual model accounts for small-scale stratigraphy; site-specific changes soil properties; tilted layers; and lateral spreading. It assumes the layers are spatially continuous causing water and solutes to move laterally across the boundary if conditions permit. Water influx at the surface is assumed to be steady. Model parameters were generated with pedotransfer functions; these were coupled high resolution neutron moisture logs that provided information on the underlying heterogeneity on a scale of 3 inches. Two approaches were used to evaluate the impact of remedial options on transport. In the first, a 1-D convolution solution to the convective-dispersive equation was used, assuming steady flow. This model was used to predict future movement of the existing plume using the mean and depth dependent moisture content. In the second approach, the STOMP model was used to first predict the current plume distribution followed by its future migration. Redistribution of the 99Tc plume was simulated for the no-action alternative and on-site capping. Hypothetical caps limiting recharge to 1.0, 0.5, and 0.1 mm yr-1 were considered and assumed not to degrade in the long term. Results show that arrival time of the MCLs, the peak arrival time, and the arrival time of the center of mass increased with decreasing recharge rate. The 1-D convolution model is easy to apply and can easily accommodate initial

  1. Fate and Transport of Nitrogen and Phosphorus in Onsite Wastewater Treatment Systems

    Science.gov (United States)

    Toor, G.; De, M.; Danmowa, N.

    2012-12-01

    The contribution of nitrogen (N) and phosphorus (P) from onsite wastewater treatment systems (OWTS) to groundwater pollution is largely not quantified in most aquifers and watersheds in the world. Thus, the knowledge about the fate and transport of N and P from OWTS is needed to protect groundwater contamination. In Florida, porous sandy soils intensify the transport of N from drianfield of OWTS to shallow groundwater. To overcome this limitation, elevated disposal fields (commonly called mounds) on top of the natural soil are constructed to provide unsaturated conditions for wastewater treatment. Our objective was to investigate the dynamics of N and P transport in the vadose zone and groundwater in full scale OWTS. We constructed three mounds: (1) drip dispersal mound: 45 cm depth of sand below the emitters, followed by natural soil; (2) gravel trench mound: 45 cm depth of sand below the emitters, followed by 30 cm depth of gravels, and natural soil; and (3) advanced system mound: which contained aerobic (lingo-cellulosic) and anaerobic (sulfur) media for enhanced nitrification and denitrification before dispersing wastewater in the vadose zone. Each mound received 120 L of septic tank effluent (STE) per day (equivalent to maximum allowable rate of 3 L/ft2/day) from our facility (office and homes); STE was dosed 6 times at 4-hour intervals in a day. Soil water samples were collected from the mounds (vadose zone) by using suction cup lysimeters installed at 0.30, 0.60, and 1.05 m depth and groundwater samples were collected by using piezometers installed at 3-3.30 m depth below mounds. We collected samples during May-Aug 2012 before STE delivery (3 events at 3-day intervals) and after STE delivery (10 events at 3-day intervals; 13 events at 7-day intervals). Collected samples (STE, soil water, groundwater) were analysed for pH, EC, chloride (Cl), and organic and inorganic N and P fractions. The ranges of pH, EC, and Cl of STE (26 events) were 6.9-7.7, 1.01-1.33 d

  2. Fate and Transport of Nitrogen and Phosphorus in Onsite Wastewater Treatment Systems

    Science.gov (United States)

    Toor, G.; De, M.; Danmowa, N.

    2012-12-01

    The contribution of nitrogen (N) and phosphorus (P) from onsite wastewater treatment systems (OWTS) to groundwater pollution is largely not quantified in most aquifers and watersheds in the world. Thus, the knowledge about the fate and transport of N and P from OWTS is needed to protect groundwater contamination. In Florida, porous sandy soils intensify the transport of N from drianfield of OWTS to shallow groundwater. To overcome this limitation, elevated disposal fields (commonly called mounds) on top of the natural soil are constructed to provide unsaturated conditions for wastewater treatment. Our objective was to investigate the dynamics of N and P transport in the vadose zone and groundwater in full scale OWTS. We constructed three mounds: (1) drip dispersal mound: 45 cm depth of sand below the emitters, followed by natural soil; (2) gravel trench mound: 45 cm depth of sand below the emitters, followed by 30 cm depth of gravels, and natural soil; and (3) advanced system mound: which contained aerobic (lingo-cellulosic) and anaerobic (sulfur) media for enhanced nitrification and denitrification before dispersing wastewater in the vadose zone. Each mound received 120 L of septic tank effluent (STE) per day (equivalent to maximum allowable rate of 3 L/ft2/day) from our facility (office and homes); STE was dosed 6 times at 4-hour intervals in a day. Soil water samples were collected from the mounds (vadose zone) by using suction cup lysimeters installed at 0.30, 0.60, and 1.05 m depth and groundwater samples were collected by using piezometers installed at 3-3.30 m depth below mounds. We collected samples during May-Aug 2012 before STE delivery (3 events at 3-day intervals) and after STE delivery (10 events at 3-day intervals; 13 events at 7-day intervals). Collected samples (STE, soil water, groundwater) were analysed for pH, EC, chloride (Cl), and organic and inorganic N and P fractions. The ranges of pH, EC, and Cl of STE (26 events) were 6.9-7.7, 1.01-1.33 d

  3. Mathematical modelling of oil spill fate and transport in the marine environment incorporating biodegradation kinetics of oil droplets

    Science.gov (United States)

    Spanoudaki, Katerina

    2016-04-01

    Oil biodegradation by native bacteria is one of the most important natural processes that can attenuate the environmental impacts of marine oil spills. However, very few numerical models of oil spill fate and transport include biodegradation kinetics of spilled oil. Furthermore, in models where biodegradation is included amongst the oil transformation processes simulated, it is mostly represented as a first order decay process neglecting the effect of several important parameters that can limit biodegradation rate, such as oil composition and oil droplets-water interface. To this end, the open source numerical model MEDSKIL-II, which simulates oil spill fate and transport in the marine environment, has been modified to include biodegradation kinetics of oil droplets dispersed in the water column. MEDSLIK-II predicts the transport and weathering of oil spills following a Lagrangian approach for the solution of the advection-diffusion equation. Transport is governed by the 3D sea currents and wave field provided by ocean circulation models. In addition to advective and diffusive displacements, the model simulates several physical and chemical processes that transform the oil (evaporation, emulsification, dispersion in the water column, adhesion to coast). The fate algorithms employed in MEDSLIK-II consider the oil as a uniform substance whose properties change as the slick weathers, an approach that can lead to reduced accuracy, especially in the estimation of oil evaporation and biodegradation. Therefore MEDSLIK-II has been modified by adopting the "pseudo-component" approach for simulating weathering processes. Spilled oil is modelled as a relatively small number of discrete, non-interacting components (pseudo-components). Chemicals in the oil mixture are grouped by physical-chemical properties and the resulting pseudo-component behaves as if it were a single substance with characteristics typical of the chemical group. The fate (evaporation, dispersion

  4. Impacts of soil redistribution on the transport and fate of organic carbon in loess soils

    NARCIS (Netherlands)

    X. Wang

    2014-01-01

    Soil erosion is an important environmental process leading to loss of topsoil including carbon (C) and nutrients, reducing soil quality and loss of biomass production. So far, the fate of soil organic carbon (SOC) in eroding landscapes is not yet fully understood and remains an important uncertainty

  5. Elucidating the fate, transport and processes controlling carbon on the landscape: Biogeochemistry tools for the 21st century

    Science.gov (United States)

    McFarlane, K. J.; Keiluweit, M.; Nico, P. S.; Ognibene, T.; Mayali, X.; Nuccio, E.; Weber, P. K.; Pett-Ridge, J.; Guilderson, T. P.

    2013-12-01

    Globally, more carbon is stored belowground as soil organic matter than in terrestrial vegetation and the atmosphere combined. A critical scientific question is how soils serve as sources and sinks for atmospheric carbon dioxide (CO2) and how these sinks will evolve with expected changes in atmospheric CO2 concentrations, climate, and land-use. Carbon initially enters belowground soil pools as plant detritus, roots, and root exudates. Once in the soil, this organic matter serves as a substrate for decomposer organisms including soil animals, bacteria, and fungi. Most of this carbon is consumed and respired as CO2, but some is converted to microbial biomass and byproducts, which may leave the soil as dissolved organic carbon, be used as a substrate by other microbes, or be stabilized within the soil mineral matrix. Mechanisms that result in the stabilization of soils include: climate stabilization, physical protection within aggregates and organo-mineral complexes, and protection of potential substrates due to physiochemical barriers. These processes, which span broad temporal and spatial scales, are poorly constrained in many dynamic land surface models. At LLNL, we have developed a suite of analytical tools that allow us to follow the movement of carbon at the cell to landscape scale, including: ';Chip-SIP', ';STXM-SIMS', and new sample interfaces for accelerator mass spectrometry (AMS). Experiments, field-based and in vivo, allow us to further the mechanistic understanding of factors that control the fate, transport, and sequestration potential of belowground carbon. The Chip-SIP approach allows us to interrogate which microbial species in a complex community incorporate specific substrates (e.g. cellulose) in order to understand the production of biofuels and better elucidate energy and carbon transfers in wetlands and soils. To disentangle the complex interactions at soil-microbial-film-mineral interfaces with minimal disruption we are using a combination of

  6. A new multimedia contaminant fate model for China:how important are environmental parameters in influencing chemical persistence and long-range transport potential?

    OpenAIRE

    Zhu, Ying; Price, Oliver R.; Tao, Shu; Jones, Kevin C.; Sweetman, Andrew

    2014-01-01

    We present a new multimedia chemical fate model (SESAMe) which was developed to assess chemical fate and behaviour across China. We apply the model to quantify the influence of environmental parameters on chemical overall persistence (POV) and long-range transport potential (LRTP) in China, which has extreme diversity in environmental conditions. Sobol sensitivity analysis was used to identify the relative importance of input parameters. Physicochemical properties were identified as more infl...

  7. Factors associated with sources, transport, and fate of volatile organic compounds and their mixtures in aquifers of the United States

    Science.gov (United States)

    Squillace, P.J.; Moran, M.J.

    2007-01-01

    Factors associated with sources, transport, and fate of volatile organic compounds (VOCs) in groundwater from aquifers throughout the United States were evaluated using statistical methods. Samples were collected from 1631 wells throughout the conterminous United States between 1996 and 2002 as part of the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey. Water samples from wells completed in aquifers used to supply drinking water were analyzed for more than 50 VOCs. Wells were primarily rural domestic water supplies (1184), followed by public water supplies (216); the remaining wells (231) supplied a variety of uses. The median well depth was 50 meters. Age-date information shows that about 60% of the samples had a fraction of water recharged after 1953. Chloroform, toluene, 1,2,4-trimethylbenzene, and perchloroethene were some of the frequently detected VOCs. Concentrations generally were less than 1 ??g/L. Source factors include, in order of importance, general land-use activity, septic/sewer density, and sites where large concentrations of VOCs are potentially released, such as leaking underground storage tanks. About 10% of all samples had VOC mixtures that were associated with concentrated sources; 20% were associated with dispersed sources. Important transport factors included well/screen depth, precipitation/groundwater recharge, air temperature, and various soil characteristics. Dissolved oxygen was strongly associated with VOCs and represents the fate of many VOCs in groundwater. Well type (domestic or public water supply) was also an important explanatory factor. Results of multiple analyses show the importance of (1) accounting for both dispersed and concentrated sources of VOCs, (2) measuring dissolved oxygen when sampling wells to help explain the fate of VOCs, and (3) limiting the type of wells sampled in monitoring networks to avoid unnecessary variance in the data, or controlling for this variance during data analysis.

  8. Geographically distributed classification of surface water chemical parameters influencing fate and behavior of nanoparticles and colloid facilitated contaminant transport.

    Science.gov (United States)

    Hammes, Julia; Gallego-Urrea, Julián A; Hassellöv, Martin

    2013-09-15

    The current production and use of nanomaterials in consumer products have increased the concern about the possibility that these enter the rivers during their entire life cycle. Further, many aquatic contaminants undergo partitioning to the ubiquitous aquatic colloids. Here is presented the development of a set of European water types for environmental risk assessment of chemicals transported as nanovectors as is the case of environmental fate of manufactured nanoparticles and colloid-bound contaminants. A compilation of river quality geochemical data with information about multi-element composition for near 800 rivers in Europe was used to perform a principal component analysis (PCA) and define 6 contrasting water classes. With the aid of geographical information system algorithms, it was possible to analyse how the different sampling locations were predominantly represented within each European water framework directive drainage basin. These water classes and their associated Debye-Hückel parameter are determining factors to evaluate the large scale fate and behaviour of nanomaterials and other colloid-transported pollutants in the European aquatic environment. PMID:23863373

  9. A study to estimate the fate and transport of bacteria in river water from birds nesting under a bridge.

    Science.gov (United States)

    Nayamatullah, M M M; Bin-Shafique, S; Sharif, H O

    2013-01-01

    To investigate the effect of input parameters, such as the number of bridge-dwelling birds, decay rate of the bacteria, flow at the river, water temperature, and settling velocity, a parametric study was conducted using a water quality model developed with QUAL2Kw. The reach of the bacterial-impaired section from the direct droppings of bridge-nesting birds at the Guadalupe River near Kerrville, Texas was estimated using the model. The concentration of Escherichia coli bacteria were measured upstream, below the bridge, and downstream of the river for one-and-a-half years. The decay rate of the indicator bacteria in the river water was estimated from the model using measured data, and was found to be 6.5/day. The study suggests that the number of bridge-dwelling birds, the decay rate, and flow at the river have the highest impact on the fate and transport of bacteria. The water temperature moderately affects the fate and transport of bacteria, whereas, the settling velocity of bacteria did not show any significant effect. Once the decay rates are estimated, the reach of the impaired section was predicted from the model using the average flow of the channel. Since the decay rate does not vary significantly in the ambient environment at this location, the length of the impaired section primarily depends on flow.

  10. Pesticide and metabolite fate, release and transport modelling at catchment scale

    Science.gov (United States)

    Gaßmann, Matthias; Olsson, Oliver; Bauer, Melanie

    2010-05-01

    Pesticides are of great concern in hydrological catchments all over the world. On the one hand they are necessary to guarantee stable agricultural production for an increasing population. On the other hand they endanger life of aquatic animals and freshwater resources. However, not only pesticides but also their degradation products, the metabolites, are toxic to the environment, in some cases even more than the parent material. Thus, it is necessary to optimize pesticide application and management of agricultural land (e.g. grass strips, erosion prevention) with respect and according to their behaviour and degradation in hydrological catchments. Modelling provides a sound tool for assessing the impacts of pesticide management changes on pesticide behaviour at the field and in consecutively surface waters. Most of the various models available in literature do not consider metabolism. This study introduces an applicable integrated model assessing the fate and release of a pesticide and one metabolite at the field and in surface waters of a hydrological catchment. For the development of the field release model, the single-equation pesticide release formula by the OECD (2000) was used, which combines sorption and degradation in one equation. The part of the equation calculating the degradation forms the input of a second OECD equation representing the metabolite with its own parameters. A fraction can be specified describing how much of the degradation product is transferred to the specific metabolite. The river network is simulated with a further development of the MOHID River Network model (MRN). The integration of a pesticide type and a metabolite, with their degradation and volatilization processes are the main improvements of the hydrodynamic channel model. Following, the combined model was set up to the Israeli part of the Upper Jordan River basin, especially the Hula valley. According to the local hydrological conditions, a linear storage with a threshold was

  11. Fate and Transport of Pharmaceutical Compounds Applied to Turf-Covered Soil

    Science.gov (United States)

    Young, M.; Green, R. L.; Devitt, D.; McCullough, M.; Wright, L.; Vanderford, B. J.; Snyder, S. A.

    2012-12-01

    In arid and semi-arid regions, the use of treated wastewater for landscape irrigation is becoming common practice and a significant asset to conserve potable water supplies. Public interest and lack of field-scale data are leading to a concern that compounds found in reuse water could persist in the environment and contaminate groundwater. As part of a larger study, 2-yr experiments were conducted in CA and NV, where reuse water was the primary source of non-ambient water input. A total of 13 compounds were studied, all originating in irrigation water applied to soil covered in turf or left bare. The target compounds included atenolol, atorvastatin, carbamazepine, diazepam, diclofenac, fluoxetine, gemfibrozil, ibuprofen, meprobamate, naproxen, primidone, sulfamethoxazole, triclosan, and trimethoprim. Analytical protocols for all compounds (detection at ng/L range) were established before the study commenced. The goals of the research were to increase available data on the fate and transport of these target compounds in turfgrass/soil systems, and to use these data to assess long-term risk from using water containing these compounds. Experiments conducted at two scales are discussed here: lysimeter-scale and field-scale. At the lysimeter-scale, 24 drainage lysimeters (120 cm thick) were exposed to treated wastewater as an irrigation source. Lysimeters varied by soil type (two types), soil cover (bare- versus turf-covered) and leaching fraction (5% and 25%). Upper and lower boundary conditions were monitored throughout the study. Water samples were collected periodically after water breakthrough. After the study, soil samples were analyzed for compound mass, allowing compound mass balance and removal to be assessed. At the field-scale, passive drain gages (Decagon Devices) were installed in triplicate in fairways at four operational golf courses, one in NV and three in CA, all with histories of using treated wastewater. The gages measure water fluxes through the 60

  12. Transport and fate of hexachlorocyclohexanes in the oceanic air and surface seawater

    Directory of Open Access Journals (Sweden)

    Z. Xie

    2011-06-01

    Full Text Available Hexachlorocyclohexanes (HCHs are ubiquitous organic pollutants derived from pesticide application. They are subject to long-range transport, persistent in the environment, and capable of accumulation in biota. Shipboard measurements of HCH isomers (α-, γ- and β-HCH in surface seawater and boundary layer atmospheric samples were conducted in the Atlantic and the Southern Ocean in October to December of 2008. ΣHCHs concentrations (the sum of α-, γ- and β-HCH in the lower atmosphere ranged from 11.8 to 36.9 pg m−3 (mean: 26.6 ± 11.0 pg m−3 in the Northern Hemisphere (NH, and from 1.5 to 4.0 pg m−3 (mean: 2.8 ± 1.1 pg m−3 in the Southern Hemisphere (SH, respectively. Water concentrations were: α-HCH 0.33–46.8 pg l−1, γ-HCH 0.02–33.2 pg l−1 and β-HCH 0.11–2 pg l−1. HCH concentrations decreased from the North Atlantic to the Southern Ocean, indicating historical use of HCHs in the NH. Spatial distribution showed increasing concentrations from the equator towards North and South latitudes illustrating the concept of cold condensation and less interhemispheric mixing process. In comparison to concentrations measured in 1987–1999/2000, gaseous HCHs were slightly lower, while dissolved HCHs decreased by factor of 2–3 orders of magnitude. Air-water exchange gradients suggested net deposition for α-HCH (mean: 3759 pg m−2 day−1 and γ-HCH (mean: 1987 pg m−2 day−1, whereas β-HCH varied between equilibrium (volatilization: <0–12 pg m−2 day−1 and net deposition (range: 6–687 pg m−2 day−1, indicating a multi-hopper transport behavior. Climate change may significantly accelerate the releasing process of "old" HCHs from continental storage (e.g. soil, vegetation and high mountains and drive long-range transport from sources to deposition in the

  13. Preferential flow effects on transport and fate of chemicals and microorganisms in soils irrigated with wastewater

    Science.gov (United States)

    Puddu, Rita; Corrias, Roberto; Dessena, Maria Antonietta; Ferralis, Marcella; Marras, Gabriele; Pin, Paola; Spanu, Paola

    2010-05-01

    This work is part of a multidisciplinary research properly planned by the ENAS (Cagliari-Sardinia-Italy) to verify the consequences of urban wastewater reuse in irrigation practices on chemical, biological and hydrological behavior of agricultural soils of the Had as Soualem area (Morocco). The area consists of Fluventic Haploxerept soils, according to USDA Soil Taxonomy. Undisturbed large soil columns, 70 cm height and 20 cm diameter, were collected from plots, the locations of which were preliminarily individuated through a prior pedological study. The soils are characterized by an apparent structure, suggesting that preferential flow processes may occur in the study area, which may impact usable groundwater at depth. Wastewater reuse for irrigation simultaneously solves water shortage and wastewater disposal problems. Unfortunately, wastewaters generally contain high concentrations of suspended and dissolved solids, both organic and inorganic, and microbial contaminants (virus and bacteria) added to wastewater during domestic and industrial usage. Most of these contaminants are only partially removed during conventional sewage treatment so they remain in the irrigation water. Although adsorbing ions and microbes are relatively immobile within porous media, preferential flow and adsorption to mobile colloids can enhance their transport. There is limited knowledge regarding the role of preferential flow and colloidal transport on adsorbing contaminants. The main aim of this research is to determine the influence of preferential flow and colloids on wastewater contaminant transport. Leaching rates and arrival time of wastewater contaminants will be determined using field and laboratory measurements at the study sites in combination with preferential flow numerical modeling. To achieve these objectives the soil columns were analyzed for physical, chemical, and microbial characterization. At the laboratory, an experimental facility was set up and sensors for

  14. Models for transport and fate of carbon, nutrients and radionuclides in the aquatic ecosystem at Oeregrundsgrepen

    International Nuclear Information System (INIS)

    The aim of the work was to provide supplementary input to the risk assessment of a planned final nuclear waste repository at Forsmark. The main deliverable was a computed water exchange between basins in the Forsmark marine area for the period 6500 BC to 9000 AD - based on the hydrodynamic modelling - to be used as input to the landscape dose model. In addition and what is described in this report, a second deliverable was development and application of high-resolution models for the marine ecosystem and radionuclide processes. The purpose of this deliverable was to illustrate the spatial and temporal variation in important processes and parameters, while constituting a complement to previous modelling approaches and providing supporting information to discussions of the marine ecosystem, parameters and variation (see Chapter 4 and 6).To this end, a hydrodynamic model of high temporal and spatial resolution was constructed and calibrated for the Forsmark area. An ecosystem model was then developed and coupled to the hydrodynamic model. In turn, a detailed radionuclide model was coupled to the ecosystem model to provide detailed predictions of radionuclide transport and accumulation in the coastal ecosystem. The ecosystem and radionuclide models were developed in the equation solver MIKE ECOLab that links seamless to the MIKE3 FM hydrodynamic model. The 'standard' ECOLab ecosystem model was extended with six biological state variables, perennial macroalgae, benthic herbivors, detritus feeders, planktivorus fish and, benthic predators representing the relict isopod Saduria and cod. In contrast to the ecosystem model, the radionuclide model was developed from scratch but building on the structure of the ecosystem model and using the output (process rates linking state variables) from the ecosystem model as input to the radionuclide model. Both the ecosystem model and the radionuclide model were run for several years (5-8 years) to bring state variables into quasi

  15. Models for transport and fate of carbon, nutrients and radionuclides in the aquatic ecosystem at Oeregrundsgrepen

    Energy Technology Data Exchange (ETDEWEB)

    Erichsen, Anders Christian; Moehlenberg, Flemming; Closter, Rikke Margrethe; Sandberg, Johannes (DHI, Hoersholm (Denmark))

    2010-06-15

    The aim of the work was to provide supplementary input to the risk assessment of a planned final nuclear waste repository at Forsmark. The main deliverable was a computed water exchange between basins in the Forsmark marine area for the period 6500 BC to 9000 AD - based on the hydrodynamic modelling - to be used as input to the landscape dose model. In addition and what is described in this report, a second deliverable was development and application of high-resolution models for the marine ecosystem and radionuclide processes. The purpose of this deliverable was to illustrate the spatial and temporal variation in important processes and parameters, while constituting a complement to previous modelling approaches and providing supporting information to discussions of the marine ecosystem, parameters and variation (see Chapter 4 and 6).To this end, a hydrodynamic model of high temporal and spatial resolution was constructed and calibrated for the Forsmark area. An ecosystem model was then developed and coupled to the hydrodynamic model. In turn, a detailed radionuclide model was coupled to the ecosystem model to provide detailed predictions of radionuclide transport and accumulation in the coastal ecosystem. The ecosystem and radionuclide models were developed in the equation solver MIKE ECOLab that links seamless to the MIKE3 FM hydrodynamic model. The 'standard' ECOLab ecosystem model was extended with six biological state variables, perennial macroalgae, benthic herbivors, detritus feeders, planktivorus fish and, benthic predators representing the relict isopod Saduria and cod. In contrast to the ecosystem model, the radionuclide model was developed from scratch but building on the structure of the ecosystem model and using the output (process rates linking state variables) from the ecosystem model as input to the radionuclide model. Both the ecosystem model and the radionuclide model were run for several years (5-8 years) to bring state variables into

  16. Biologically mediated transport of contaminants to aquatic systems.

    Science.gov (United States)

    Blais, Jules M; Macdonald, Robie W; Mackay, Donald; Webster, Eva; Harvey, Colin; Smol, John P

    2007-02-15

    The prevailing view is that long-range transport of semivolatile contaminants is primarily conducted by the physical system (e.g., winds, currents), and biological transport is typically ignored. Although this view may be correct in terms of bulk budgets and fluxes, it neglects the potential of animals to focus contaminants into foodwebs due to their behaviors and lifecycles. In particular, gregarious animals that biomagnify and bioaccumulate certain contaminants and then migrate and congregate can become the predominant pathway for contaminants in many circumstances. Fish and birds provide prominent examples for such behavior. This review examines the potential for biovector transport to expose populations to contaminants. In addition, we apply a modeling approach to compare the potential of biovector transport to other physical transport pathways for a hypothetical lake receiving large numbers of fish. We conclude that biovector transport should not be neglected when considering environmental risks of biomagnifying contaminants.

  17. A Reflection on the Fate of Chiral 1,2,4-Triazole Fungicides in Biological Systems

    Science.gov (United States)

    In biological systems, stereoisomers of chiral compounds can exhibit significantly different pharmacokinetics (absorption, distribution, metabolism, and elimination) and pharmacodynamics (physiological effects). Pharmacokinetic processes (i.e., what the body does to the chemical)...

  18. Transport and fate of hexachlorocyclohexanes in the oceanic air and surface seawater

    Directory of Open Access Journals (Sweden)

    Z. Xie

    2011-09-01

    Full Text Available Hexachlorocyclohexanes (HCHs are ubiquitous organic pollutants derived from pesticide application. They are subject to long-range transport, persistent in the environment, and capable of accumulation in biota. Shipboard measurements of HCH isomers (α-, γ- and β-HCH in surface seawater and boundary layer atmospheric samples were conducted in the Atlantic and the Southern Ocean in October to December of 2008. ΣHCHs concentrations (the sum of α-, γ- and β-HCH in the lower atmosphere ranged from 12 to 37 pg m−3 (mean: 27 ± 11 pg m−3 in the Northern Hemisphere (NH, and from 1.5 to 4.0 pg m−3 (mean: 2.8 ± 1.1 pg m−3 in the Southern Hemisphere (SH, respectively. Water concentrations were: α-HCH 0.33–47 pg l−1, γ-HCH 0.02–33 pg l−1 and β-HCH 0.11–9.5 pg l−1. Dissolved HCH concentrations decreased from the North Atlantic to the Southern Ocean, indicating historical use of HCHs in the NH. Spatial distribution showed increasing concentrations from the equator towards North and South latitudes illustrating the concept of cold trapping in high latitudes and less interhemispheric mixing process. In comparison to concentrations measured in 1987–1999/2000, gaseous HCHs were slightly lower, while dissolved HCHs decreased by factor of 2–3 orders of magnitude. Air-water exchange gradients suggested net deposition for α-HCH (mean: 3800 pg m−2 day−1 and γ-HCH (mean: 2000 pg m−2 day−1, whereas β-HCH varied between equilibrium (volatilization: <0–12 pg m−2 day−1 and net deposition (range: 6–690 pg m−2 day−1. Climate change may significantly accelerate the release of "old" HCHs from continental storage (e.g. soil, vegetation and high mountains and drive long-range transport from sources to deposition in the open oceans. Biological productivities may

  19. Evaluate and characterize mechanisms controlling transport, fate and effects of army smokes in an aerosol wind tunnel: Transport, transformations, fate and terrestrial ecological effects of fog oil obscurant smokes: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Cataldo, D.A.; Van Voris, P.; Ligotke, M.W.; Fellows, R.J.; McVeety, B.D.; Li, Shu-mei W.; Bolton, H. Jr.; Fredrickson, J.K.

    1989-01-01

    The terrestrial transport, chemical fate, and ecological effects of fog oil (FO) smoke obscurants were evaluated under controlled wind tunnel conditions. The primary objectives of this research program are to characterize and assess the impacts of smoke and obscurants on: (1) natural vegetation characteristic of US Army training sites in the United States; (2) physical and chemical properties of soils representative of these training sites; and (3) soil microbiological and invertebrate communities. Impacts and dose/responses were evaluated based on an exposure scenario, including exposure duration, exposure rate, and sequential cumulative dosing. Key to understanding the environmental impacts of fog oil smoke/obscurants is establishing the importance of environmental parameters, such as relative humidity and wind speed on airborne aerosol characteristics and deposition to receptor surfaces. Direct and indirect biotic effects were evaluated using five plant species and three soil types. 29 refs., 35 figs., 32 tabs.

  20. In Vivo Integrity and Biological Fate of Chelator-Free Zirconium-89-Labeled Mesoporous Silica Nanoparticles.

    Science.gov (United States)

    Chen, Feng; Goel, Shreya; Valdovinos, Hector F; Luo, Haiming; Hernandez, Reinier; Barnhart, Todd E; Cai, Weibo

    2015-08-25

    Traditional chelator-based radio-labeled nanoparticles and positron emission tomography (PET) imaging are playing vital roles in the field of nano-oncology. However, their long-term in vivo integrity and potential mismatch of the biodistribution patterns between nanoparticles and radio-isotopes are two major concerns for this approach. Here, we present a chelator-free zirconium-89 ((89)Zr, t1/2 = 78.4 h) labeling of mesoporous silica nanoparticle (MSN) with significantly enhanced in vivo long-term (>20 days) stability. Successful radio-labeling and in vivo stability are demonstrated to be highly dependent on both the concentration and location of deprotonated silanol groups (-Si-O(-)) from two types of silica nanoparticles investigated. This work reports (89)Zr-labeled MSN with a detailed labeling mechanism investigation and long-term stability study. With its attractive radio-stability and the simplicity of chelator-free radio-labeling, (89)Zr-MSN offers a novel, simple, and accurate way for studying the in vivo long-term fate and PET image-guided drug delivery of MSN in the near future.

  1. Development of Alternate Soil Clean-Up Goals for Hanford Waste Sites Using Fate and Transport Modeling

    International Nuclear Information System (INIS)

    Remedial Action Goals (RAGs) for soil contaminant levels that are protective of groundwater have been determined for the Removal/Treatment/Disposal (RTD) sites at the 200-UW-1 Operable Unit on the Hanford Site. The RAG values were determined using a methodology involving the back-calculation of soil contaminant levels protective of groundwater (i.e., resulting groundwater concentrations are ≤ MCLs) in conjunction with the fate and transport modeling as a risk-based alternative to the currently prescribed use of background or detection limit default values. This methodology is important for waste management activities at the Hanford Site because it provides risk-based metrics and a technical basis for determining the levels of contamination 'left in place' in the Hanford Site vadose zone that are protective of human health and the environment. The methodology and the use of fate and transport modeling described here comply with federal guidelines for the use of environmental models. This approach is also consistent with one of several allowable methods identified in State guidelines for deriving soil concentrations for ground water protection. Federal and state guidelines recommend the use of site-specific information and data in risk-based assessments of risk and/or protectiveness. The site-specific characteristics of the Hanford Site, which include consideration of the semi-arid climate, an unsaturated zone thickness of over 80 m (262 feet), and associated/other site features and processes, are integral for the risk-based assessments associated with the protection of groundwater pathway. This methodology yields soil cleanup values (RAGs) for the 200-UW-1 OU waste sites selected for the removal/treatment/disposal (RTD) remedy. These proposed RAGs for uranium, nitrate, and technetium-99 are derived from soil concentrations calculated not to cause contamination of groundwater at levels that exceed the ground water MCLs, and are 40 to 200 times greater than

  2. Spatially distributed influence of agro-environmental factors governing nitrate fate and transport in an irrigated stream-aquifer system

    Science.gov (United States)

    Bailey, R. T.; Ahmadi, M.; Gates, T. K.; Arabi, M.

    2015-12-01

    Elevated levels of nitrate (NO3) in groundwater systems pose a serious risk to human populations and natural ecosystems. As part of an effort to remediate NO3 contamination in irrigated stream-aquifer systems, this study elucidates agricultural and environmental parameters and processes that govern NO3 fate and transport at the regional (500 km2), local (50 km2), and field scales (humus decomposition also dominate or partially dominate in other locations. Each factor, with the exception of O2 reduction rate, is the dominating influence on NO3 groundwater concentration at one or more locations within the study area. Results can be used to determine critical processes and key management actions for future data collection and remediation strategies, with efforts able to be focused on localized areas.

  3. Models for transport and fate of carbon, nutrients and radionuclides in the aquatic ecosystem at Oeregrundsgrepen

    Energy Technology Data Exchange (ETDEWEB)

    Erichsen, Anders Christian; Moehlenberg, Flemming; Closter, Rikke Margrethe; Sandberg, Johannes (DHI, Hoersholm (Denmark))

    2010-06-15

    The aim of the work was to provide supplementary input to the risk assessment of a planned final nuclear waste repository at Forsmark. The main deliverable was a computed water exchange between basins in the Forsmark marine area for the period 6500 BC to 9000 AD - based on the hydrodynamic modelling - to be used as input to the landscape dose model. In addition and what is described in this report, a second deliverable was development and application of high-resolution models for the marine ecosystem and radionuclide processes. The purpose of this deliverable was to illustrate the spatial and temporal variation in important processes and parameters, while constituting a complement to previous modelling approaches and providing supporting information to discussions of the marine ecosystem, parameters and variation (see Chapter 4 and 6).To this end, a hydrodynamic model of high temporal and spatial resolution was constructed and calibrated for the Forsmark area. An ecosystem model was then developed and coupled to the hydrodynamic model. In turn, a detailed radionuclide model was coupled to the ecosystem model to provide detailed predictions of radionuclide transport and accumulation in the coastal ecosystem. The ecosystem and radionuclide models were developed in the equation solver MIKE ECOLab that links seamless to the MIKE3 FM hydrodynamic model. The 'standard' ECOLab ecosystem model was extended with six biological state variables, perennial macroalgae, benthic herbivors, detritus feeders, planktivorus fish and, benthic predators representing the relict isopod Saduria and cod. In contrast to the ecosystem model, the radionuclide model was developed from scratch but building on the structure of the ecosystem model and using the output (process rates linking state variables) from the ecosystem model as input to the radionuclide model. Both the ecosystem model and the radionuclide model were run for several years (5-8 years) to bring state variables into

  4. Numerical modelling on fate and transport of petroleum hydrocarbons in an unsaturated subsurface system for varying source scenario

    Indian Academy of Sciences (India)

    M Berlin; M Vasudevan; G Suresh Kumar; Indumathi M Nambi

    2015-04-01

    The vertical transport of petroleum hydrocarbons from a surface spill through an unsaturated subsurface system is of major concern in assessing the vulnerability of groundwater contamination. A realistic representation on fate and transport of volatile organic compounds at different periods after spill is quite challenging due to the variation in the source behaviour at the surface of spill as well as the variation in the hydrodynamic parameters and the associated inter-phase partitioning coefficients within the subsurface. In the present study, a one dimensional numerical model is developed to simulate the transport of benzene in an unsaturated subsurface system considering the effect of volatilization, dissolution, adsorption and microbial degradation of benzene for (i) constant continuous source, (ii) continuous decaying source, and (iii) residual source. The numerical results suggest that volatilization is the important sink for contaminant removal considering the soil air migration within the unsaturated zone. It is also observed that the coupled effect of dissolution and volatilization is important for the decaying source at the surface immediately after the spill, whereas rate-limited dissolution from residually entrapped source is responsible for the extended contamination towards later period.

  5. Fate of dissolved organic nitrogen during biological nutrient removal wastewater treatment processes.

    Science.gov (United States)

    Liu, Bing; Lin, Huirong; Yu, Guozhong; Zhang, Shenghua; Zhao, Chengmei

    2013-04-01

    Due to its potential to form toxic nitrogenous disinfection byproducts (N-DBPs), dissolved organic nitrogen (DON) is considered as one of the most important parameters in wastewater treatment plants (WWTP). This study describes a comprehensive investigation of variations in DON levels in orbal oxidation ditches. The results showed that DON increased gradually from 0.71 to 1.14 mg I(-1) along anaerobic zone, anoxic zone, aerobic zone 1 and aerobic 2. Molecular weight fractionation of DON in one anaerobic zone and one aerobic zone (aerobic zone 2) was performed. We found that the proportion of small molecular weight ( 20 kDa) showed opposite trend. This variation may have been caused due to the release of different types of soluble microbial products (SMPs) during biological processes. These SMPs contained both tryptophan protein-like and aromatic protein-like substances, which were confirmed by three-dimensional excitation-emission matrix (EEM) analysis. PMID:24620601

  6. Continuous Modeling of Calcium Transport Through Biological Membranes

    Science.gov (United States)

    Jasielec, J. J.; Filipek, R.; Szyszkiewicz, K.; Sokalski, T.; Lewenstam, A.

    2016-08-01

    In this work an approach to the modeling of the biological membranes where a membrane is treated as a continuous medium is presented. The Nernst-Planck-Poisson model including Poisson equation for electric potential is used to describe transport of ions in the mitochondrial membrane—the interface which joins mitochondrial matrix with cellular cytosis. The transport of calcium ions is considered. Concentration of calcium inside the mitochondrion is not known accurately because different analytical methods give dramatically different results. We explain mathematically these differences assuming the complexing reaction inside mitochondrion and the existence of the calcium set-point (concentration of calcium in cytosis below which calcium stops entering the mitochondrion).

  7. BETR-world: A geographically explicit model of chemical fate: Application to transport of a-HCH to the arctic

    Energy Technology Data Exchange (ETDEWEB)

    Toose, Liisa; Woodfine, David G.; MacLeod, Matthew; Mackay, Don; Gouin, Jenn

    2003-12-01

    The Berkeley Trent (BETR)-World model, a 25 compartment, geographically explicit fugacity-based model is described and applied to evaluate the transport of chemicals from temperate source regions to receptor regions (such as the Arctic). The model was parameterized using GIS and an array of digital data on weather, oceans, freshwater, vegetation and geo-political boundaries. This version of the BETR model framework includes modification of atmospheric degradation rates by seasonally variable hydroxyl radical concentrations and temperature. Degradation rates in all other compartments vary with seasonally changing temperature. Deposition to the deep ocean has been included as a loss mechanism. A case study was undertaken for a-HCH. Dynamic emission scenarios were estimated for each of the 25 regions. Predicted environmental concentrations showed good agreement with measured values for the northern regions in air , and fresh and oceanic water and with the results from a previous model of global chemical fate. Potential for long-range transport and deposition to the Arctic region was assessed using a Transfer Efficiency combined with estimated emissions. European regions and the Orient including China have a high potential to contribute a-HCH contamination in the Arctic due to high rates of emission in these regions despite low Transfer Efficiencies. Sensitivity analyses reveal that the performance and reliability of the model is strongly in sequenced by parameters controlling degradation rates.

  8. Chromium(VI) transport and fate in unsaturated zone and aquifer: 3D Sandbox results.

    Science.gov (United States)

    Zhao, Xingmin; Sobecky, Patricia A; Zhao, Lanpo; Crawford, Patrice; Li, Mingtang

    2016-04-01

    The simulation of Cr(VI) behavior in an unsaturated zone and aquifer, using a 3D experimental set-up were performed to illustrate the distribution, transport and transformation of Cr(VI), and further to reveal the potential harm of Cr(VI) after entering the groundwater. The result indicated that chromium(VI) was transported in the vertical direction, meanwhile, was transported in the horizontal direction under the influence of groundwater flow. The direction and distance away from the pollution source zone had great effect on the chromium(VI) concentration. At the sampling sites near the pollution source zone, there was a sudden increase of chromium(VI) concentration. The concentration of chromium(III) concentration in some random effluent samples was not detected. Chromium had not only transported but also had fraction and specie transformation in the unsaturated zone and aquifer. The relative concentration of residue fraction chromium was decreased with time. The content of Fe-Mn oxide fraction chromium was increased with time. The relative content of exchangeable and carbonate-bound fraction chromium was lower and the content variations were not obvious. Chromium(VI) (91-98%) was first reduced to chromium(III) rapidly. The oxidation reaction occurred later and the relative content of chromium(VI) was increased again. The presence of manganese oxides under favorable soil conditions can promote the reoxidation of Cr(III) to Cr(VI).

  9. Normal and impaired charge transport in biological systems

    Energy Technology Data Exchange (ETDEWEB)

    Miller, John H., E-mail: jhmiller@uh.edu [Department of Physics & Texas Center for Superconductivity, University of Houston, Houston, TX 77204-5005 (United States); Villagrán, Martha Y. Suárez; Maric, Sladjana [Department of Physics & Texas Center for Superconductivity, University of Houston, Houston, TX 77204-5005 (United States); Briggs, James M. [Department of Biology & Biochemistry, University of Houston, Houston, TX 77204-5001 (United States)

    2015-03-01

    We examine the physics behind some of the causes (e.g., hole migration and localization that cause incorrect base pairing in DNA) and effects (due to amino acid replacements affecting mitochondrial charge transport) of disease-implicated point mutations, with emphasis on mutations affecting mitochondrial DNA (mtDNA). First we discuss hole transport and localization in DNA, including some of our quantum mechanical modeling results, as they relate to certain mutations in cancer. Next, we give an overview of electron and proton transport in the mitochondrial electron transport chain, and how such transport can become impaired by mutations implicated in neurodegenerative diseases, cancer, and other major illnesses. In particular, we report on our molecular dynamics (MD) studies of a leucine→arginine amino acid replacement in ATP synthase, encoded by the T→G point mutation at locus 8993 of mtDNA. This mutation causes Leigh syndrome, a devastating maternally inherited neuromuscular disorder, and has been found to trigger rapid tumor growth in prostate cancer cell lines. Our MD results suggest, for the first time, that this mutation adversely affects water channels that transport protons to and from the c-ring of the rotary motor ATP synthase, thus impairing the ability of the motor to produce ATP. Finally, we discuss possible future research topics for biological physics, such as mitochondrial complex I, a large proton-pumping machine whose physics remains poorly understood.

  10. BETR-World: a geographically explicit model of chemical fate: application to transport of {alpha}-HCH to the Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Toose, L.; Woodfine, D.G.; MacLeod, M.; Mackay, D.; Gouin, J

    2004-03-01

    The Berkeley-Trent (BETR)-World model, a 25 compartment, geographically explicit fugacity-based model is described and applied to evaluate the transport of chemicals from temperate source regions to receptor regions (such as the Arctic). The model was parameterized using GIS and an array of digital data on weather, oceans, freshwater, vegetation and geo-political boundaries. This version of the BETR model framework includes modification of atmospheric degradation rates by seasonally variable hydroxyl radical concentrations and temperature. Degradation rates in all other compartments vary with seasonally changing temperature. Deposition to the deep ocean has been included as a loss mechanism. A case study was undertaken for {alpha}-HCH. Dynamic emission scenarios were estimated for each of the 25 regions. Predicted environmental concentrations showed good agreement with measured values for the northern regions in air, and fresh and oceanic water and with the results from a previous model of global chemical fate. Potential for long-range transport and deposition to the Arctic region was assessed using a Transfer Efficiency combined with estimated emissions. European regions and the Orient including China have a high potential to contribute {alpha}-HCH contamination in the Arctic due to high rates of emission in these regions despite low Transfer Efficiencies. Sensitivity analyses reveal that the performance and reliability of the model is strongly influenced by parameters controlling degradation rates. - A geographically explicit multi-compartment model is applied to the transport of {alpha}-HCH to the Arctic, showing Europe and the Orient are key sources.

  11. Transport and fate of river waters under flood conditions and rim current influence: the Mississippi River test case

    Science.gov (United States)

    Kourafalou, Villy; Androulidakis, Yannis

    2013-04-01

    Large river plumes are a major supplier of freshwater, sediments and nutrients in coastal and shelf seas. Novel processes controlling the transport and fate of riverine waters (and associated materials) will be presented, under flood conditions and in the presence of complex topography, ambient shelf circulation and slope processes, controlled by the interaction with rim currents. The Mississippi River (MR) freshwater outflow is chosen as a test case, as a major circulation forcing mechanism for the Northern Gulf of Mexico and a unique river plume for the intense interactions with a large scale ocean current, namely the Loop Current branch of the Gulf Stream, and associated eddy field. The largest MR outflow in history (45,000 m3/sec in 2011) is compared with the second largest outflow in the last 8 years (41,000 m3/sec in 2008). Realistically forced simulations, based on the Hybrid Coordinate Ocean Model (HYCOM) with careful treatment of river plume dynamics and nested to a data assimilated, basin-wide model, reveal the synergistic effect of enhanced discharge, winds, stratification of ambient shelf waters and offshore circulation over the transport of plume waters. The investigation targets a broader understanding of the dynamics of large scale river plumes in general, and of the MR plume in particular. In addition, in situ observations from ship surveys and satellite chl-a data showed that the mathematical simulations with high temporal resolution river outflow input may reproduce adequately the buoyant waters spreading over the Northern Gulf of Mexico shelf and offshore areas. The fate of the river plume is strongly determined and affected by deep basin processes. The strong impacts of the Loop Current system (and its frontal eddies) on river plume evolution are of particular importance under conditions of increased offshore spreading, which is presumed under large discharge rates and can cause loss of riverine materials to the basin interior. Flood conditions

  12. Fate and transport of mercury in soil systems : a numerical model in HP1 and sensitivity analysis

    Science.gov (United States)

    Leterme, Bertrand; Jacques, Diederik

    2013-04-01

    Mercury (Hg) poses threats for human health and the environment, notably due to its persistence and its ability to bioaccumulate in ecosystems. Anthropogenic activities are major contributors of mercury release to soils. Main sources of contamination include manufacturing (chlor-alkali plants, manometer spill), mine tailings from mercury, gold and silver mining industries, wood preservation. The objective of this study was to develop a reactive transport model for simulating mercury fate and transport in the unsaturated zone, and to gain insight in the fate and transport of Hg following anthropogenic soil contamination. The present work is done in the framework of the IMaHg project, which aims at providing recommendations to improve management of sites contaminated by mercury within the SNOWMAN funding framework. A model of mercury fate and transport in soil systems was developed using the reactive transport code HP1 (Jacques and Šimůnek, 2010). The geochemical database THERMODDEM (Blanc et al., 2012) is used, augmented with some speciation data from (Skyllberg, 2012). The main processes accounted for in the model are : Hg aqueous speciation (including complexation with dissolved organic matter (DOM) - humic and fulvic acids, and thiol groups), Hg sorption to solid organic matter (SOM), dissolution of solid phase Hg (e.g. cinnabar HgS(s)), dissolution of Hg non-aqueous liquid phase (NAPL), sunlight-driven Hg(II) reduction to Hg(0), Hg(0) diffusion in the gas phase and volatilization, DOM sorption to soil minerals. Colloid facilitated transport is implicitly accounted for by solute transport of Hg-DOM complexes. Because we focused on soil systems having a high Hg contamination, some processes showing relatively smaller Hg fluxes could be neglected such as vegetation uptake and atmospheric wet and dry deposition. NAPL migration and entrapment is not modelled, as pollution is assumed to be historical and only residual NAPL to be present. Mercury methylation and

  13. Fate and Transport of Road Salt During Snowmelt Through a Calcareous Fen: Kampoosa Bog, Stockbridge, Massachusetts

    Science.gov (United States)

    Rhodes, A. L.; Guswa, A. J.; Pufall, A.

    2007-12-01

    Kampoosa Bog is the largest and most ecologically diverse calcareous lake-basin fen in Massachusetts. Situated within a 4.7 km2 drainage basin, the open fen (approx. 20 acres) consists of a floating mat of sedges (incl. Carex aquatilis and Cladium mariscoides) that overlie peat and lake clay deposits. Mineral weathering of marble bedrock within the drainage basin supplies highly alkaline ground and surface waters to the fen basin. The natural chemistry has been greatly altered by road salt runoff from the Massaschusetts Turnpike, and in question is whether disturbance from the Turnpike and a gas pipline has facilitated aggressive growth by the invasive species Phragmites australis. Considered to be one of the most significant rare species habitats in the state, Massachusetts has designated Kampoosa Bog an Area of Critical Environmental Concern, and a committee representing several local, regional, and state agencies, organizations, and citizens manages the wetland. The purpose of this study is to characterize the hydrologic and chemical response of the wetland during snowmelt events to understand the fate and movement of road salt (NaCl). Concentrations of Na and Cl in the fen groundwater are greatest close to the Turnpike. Concentrations decrease with distance downstream but are still greatly elevated relative to sites upstream of the Turnpike. During snowmelt events, the fen's outlet shows a sharp rise in Na and Cl concentrations at the onset of melting that is soon diluted by the added meltwater. The Na and Cl flux, however, is greatest at peak discharge, suggesting that high-flow events are significant periods of export of dissolved salts from the fen. Pure dissolution of rock salt produces an equal molar ratio between Na and Cl, and sodium and chloride imbalances in stream and ground waters suggest that ~20% of the Na is stored on cation exchange sites within the peat. The largest imbalances between Na and Cl occur deeper within the peat, where the peat is

  14. Transport and fate of the herbicide diclofop-methyl in a large-scale physical model

    Science.gov (United States)

    Lawrence, J. R.; Hendry, M. J.; Zanyk, B. N.; Wolfaardt, G. M.

    1995-07-01

    A 3.6-m-thick unsaturated zone was constructed in a mesoscale model (2.4-m diameter by 4.6 m high, 65 tonnes) consisting of A, B and C profiles. The model was designed to be a homogeneous isotropic system. Assuming piston flow the estimated transit time for water through the unsaturated zone (3.3 m) under steady-state conditions was 25-30 days. Monitoring of major ions, metals, pH, alkalinity, CO 2, N 2, O 2, CH 4 and other parameters indicated that the system approached chemical steady state after ˜ 130-150 days. The herbicide diclofop-methyl was applied to ground surface on day 78. The migration of the herbicide was monitored at intervals using suction lysimeters to collect pore-water samples. Diclofop was detected in the 0.08-, 0.22-, 0.36- and 0.54-m-depth samplers. However, the timing of detection, at 0.08 m immediately after application, 0.54 m after 4 days, and 0.22 and 0.36 m after 12 days indicated the presence of preferential flow paths. Studies of the surface CO 2 flux and water chemistry at 0.85 m further supported the existence of preferential flow. A fluorescein treatment was applied (day 345) to the surface and the model was systematically sampled and excavated (day 348), under ultra violet illumination, to further examine flow patterns and paths. Mapping of the distribution of fluorescein and examination of vertical sections confirmed that several pathways existed within the A and B horizons. These observations explained the observed distribution of diclofop within the system. The diclofop dissipated at all sample depths within 35 days of application. Further studies were carried out to determine the fate of 14C labeled diclofop-methyl in A, B and C horizon materials derived from the model. The results of these studies indicated that the maximum conversion of diclofop to CO 2 in each of the horizons A, B and C was 1%, 59% and 75%, respectively. These studies indicated that inhomogeneities in the reconstructed soil profile were the major path for

  15. The Fate and Transport of Glyphosate and AMPA into Surface Waters of Agricultural Watersheds

    Science.gov (United States)

    Coupe, R.; Kalkhoff, S.; Capel, P.; Gregoire, C.

    2010-12-01

    Glyphosate [N-(phosphonomethyl)glycine] is a herbicide used widely throughout the world in the production of many crops, but is particularly heavily used on crops which are genetically modified to be glyphosate tolerant: predominately soybeans, corn, potatoes, and cotton. Glyphosate is used extensively in almost all agricultural areas of the United States, and annual application has increased from less than 10,000 Mg in 1992 to more than 80,000 Mg in 2007. The greatest areal use is in the Midwest where glyphosate is applied on genetically modified corn and soybeans. Although use is increasing, the characterization of glyphosate transport on the watershed scale is lacking. Glyphosate, and its degradate AMPA [aminomethylphosphoric acid], was frequently detected in the surface waters of four agricultural watersheds. The load as a percent of use of glyphosate ranged from 0.009 to 0.86 percent and can be related to three factors: source strength, hydrology, and flowpath. Glyphosate use within a watershed results in some occurrence in surface water at the part per billion level; however watersheds most at risk for the offsite transport of glyphosate are those with high application rates, rainfall that results in overland runoff, and a flowpath that does not include transport through the soil.

  16. Fate and transport of glyphosate and aminomethylphosphonic acid in surface waters of agricultural basins

    Science.gov (United States)

    Coupe, R.H.; Kalkhoff, S.J.; Capel, P.D.; Gregoire, C.

    2012-01-01

    Background: Glyphosate [N-(phosphonomethyl)glycine] is a herbicide used widely throughout the world in the production of many crops and is heavily used on soybeans, corn and cotton. Glyphosate is used in almost all agricultural areas of the United States, and the agricultural use of glyphosate has increased from less than 10 000 Mg in 1992 to more than 80 000 Mg in 2007. The greatest intensity of glyphosate use is in the midwestern United States, where applications are predominantly to genetically modified corn and soybeans. In spite of the increase in usage across the United States, the characterization of the transport of glyphosate and its degradate aminomethylphosphonic acid (AMPA) on a watershed scale is lacking. Results: Glyphosate and AMPA were frequently detected in the surface waters of four agricultural basins. The frequency and magnitude of detections varied across basins, and the load, as a percentage of use, ranged from 0.009 to 0.86% and could be related to three general characteristics: source strength, rainfall runoff and flow route. Conclusions: Glyphosate use in a watershed results in some occurrence in surface water; however, the watersheds most at risk for the offsite transport of glyphosate are those with high application rates, rainfall that results in overland runoff and a flow route that does not include transport through the soil. ?? 2011 Society of Chemical Industry.

  17. Modeling Fate and Transport of Cryptosporidium Parvum Oocysts in Overland and Near- surface Flow

    Science.gov (United States)

    Bhattarai, R.; Kalita, P.; Kuhlenschmidt, M. S.

    2008-12-01

    Cryptosporidium parvum is a manure-borne protozoan parasite which is common in the environment. It has been recognized as an important microbial contaminant of water and can cause infection and diarrhea in many mammalian hosts, including humans. The laboratory experiments carried out have demonstrated that recovery of C. parvum oocysts was significantly affected by climatic and surface conditions like slope, rainfall and surface cover. The objective of this study is to develop a model for simulating transport of C. parvum oocysts in overland and near-surface flow. Modeling can help understanding oocysts transport pathways. Accordingly, best management practices (BMP) can be developed. Transport of oocysts in overland flow can be simulated mathematically by including terms for the concentration of the oocysts in the liquid phase (in suspension or free-floating) and the solid phase (adsorbed to the fine solid particles like clay). Oocysts adsorption, advection and decay processes are considered. These processes are solved using numerical technique to predict spatial and temporal changes in oocyst concentrations in solid and liquid phases. The model results are compared with experimental data to validate the model outcome. The model output reproduced observed recovery kinetics for 1.5% slope but not for higher slopes (3.0% and 4.5%).

  18. A multimedia fate and chemical transport modeling system for pesticides: I. Model development and implementation

    Science.gov (United States)

    Li, Rong; Scholtz, M. Trevor; Yang, Fuquan; Sloan, James J.

    2011-07-01

    We have combined the US EPA MM5/MCIP/SMOKE/CMAQ modeling system with a dynamic soil model, the pesticide emission model (PEM), to create a multimedia chemical transport model capable of describing the important physical and chemical processes involving pesticides in the soil, in the atmosphere, and on the surface of vegetation. These processes include: agricultural practices (e.g. soil tilling and pesticide application mode); advection and diffusion of pesticides, moisture, and heat in the soil; partitioning of pesticides between soil organic carbon and interstitial water and air; emissions from the soil to the atmosphere; gas-particle partitioning and transport in the atmosphere; and atmospheric chemistry and dry and wet deposition of pesticides to terrestrial and water surfaces. The modeling system was tested by simulating toxaphene in a domain that covers most of North America for the period from 1 January 2000 to 31 December 2000. The results show obvious transport of the pesticide from the heavily contaminated soils in the southern United States and Mexico to water bodies including the Atlantic Ocean, the Gulf of Mexico and the Great Lakes, leading to significant dry and wet deposition into these ecosystems. The spatial distributions of dry and wet depositions differ because of their different physical mechanisms; the former follows the distribution of air concentrations whereas the latter is more biased to the North East due to the effect of precipitation.

  19. Review of Bioassays for Monitoring Fate and Transport ofEstrogenic Endocrine Disrupting Compounds in Water

    Energy Technology Data Exchange (ETDEWEB)

    CGCampbell@lbl.gov

    2004-01-30

    Endocrine disrupting compounds (EDCs) are recognizedcontaminants threatening water quality. Despite efforts in sourceidentification, few strategies exist for characterization or treatment ofthis environmental pollution. Given that there are numerous EDCs that cannegatively affect humans and wildlife, general screening techniques likebioassays and biosensors provide an essential rapid and intensiveanalysis capacity. Commonly applied bioassays include the ELISA and YESassays, but promising technologies include ER-CALUXa, ELRA, Endotecta,RIANA, and IR-bioamplification. Two biosensors, Endotecta and RIANA, arefield portable using non-cellular biological detection strategies.Environmental management of EDCs in water requires integration ofbiosensors and bioassays for monitoring and assessment.

  20. Geochemical Evaluation of Uranium Fate and Transport Guterl Specialty Steel Site, New York - 12077

    International Nuclear Information System (INIS)

    Between 1948 and 1952, up to 15,875 metric tons (35 million pounds) of natural uranium metal (U) were processed at the former Guterl Specialty Steel Corporation site in Lockport, New York. The resulting dust, thermal scale, mill shavings and associated land disposal contaminated both the facility and on-site soils. Uranium subsequently impacted groundwater and a fully developed plume exists below the site. Site soils are composed of anthropogenic fill and re-worked, glacially-derived native soil. This overburden is underlain by the weathered and fractured Lockport Dolostone bedrock. Shallow groundwater levels fluctuate seasonally and allow groundwater to contact U contaminated soil, which promotes transport. This condition is exemplified through coincident increases in specific conductivity and groundwater levels, which flush soluble constituents in the fill/soil to groundwater during recharge events. In addition, water-level fluctuations affect reduction-oxidation (redox) conditions at the site. The U in soils is subject to wetting and drying cycles that promote oxidation more than stable redox conditions (e.g., dry soil or fully saturated conditions). This oxidizing mechanism increases uranium solubility and mobility. Site groundwater also receives uranium via leaching from near-surface contaminated fill. The strong correlation between nitrate and uranium in groundwater indicates that uranium is mobile where oxidizing conditions occur. Analytical models of contaminant leaching determined that multiple pathways and transport mechanisms govern site risk. Uranium transport to groundwater involves three mechanisms: 1) direct contact of contaminated soil with groundwater, 2) the oxidation-state or chemical valence of uranium, and 3) the leaching of near-surface contamination to groundwater. These mechanisms require an integrated remedial solution that is sustainable and cost effective. (authors)

  1. A multimedia fate and chemical transport modeling system for pesticides: II. Model evaluation

    Science.gov (United States)

    Li, Rong; Scholtz, M. Trevor; Yang, Fuquan; Sloan, James J.

    2011-07-01

    Pesticides have adverse health effects and can be transported over long distances to contaminate sensitive ecosystems. To address problems caused by environmental pesticides we developed a multimedia multi-pollutant modeling system, and here we present an evaluation of the model by comparing modeled results against measurements. The modeled toxaphene air concentrations for two sites, in Louisiana (LA) and Michigan (MI), are in good agreement with measurements (average concentrations agree to within a factor of 2). Because the residue inventory showed no soil residues at these two sites, resulting in no emissions, the concentrations must be caused by transport; the good agreement between the modeled and measured concentrations suggests that the model simulates atmospheric transport accurately. Compared to the LA and MI sites, the measured air concentrations at two other sites having toxaphene soil residues leading to emissions, in Indiana and Arkansas, showed more pronounced seasonal variability (higher in warmer months); this pattern was also captured by the model. The model-predicted toxaphene concentration fraction on particles (0.5-5%) agrees well with measurement-based estimates (3% or 6%). There is also good agreement between modeled and measured dry (1:1) and wet (within a factor of less than 2) depositions in Lake Ontario. Additionally this study identified erroneous soil residue data around a site in Texas in a published US toxaphene residue inventory, which led to very low modeled air concentrations at this site. Except for the erroneous soil residue data around this site, the good agreement between the modeled and observed results implies that both the US and Mexican toxaphene soil residue inventories are reasonably good. This agreement also suggests that the modeling system is capable of simulating the important physical and chemical processes in the multimedia compartments.

  2. Modelling fate and transport of glyphosate and AMPA in the Meuse catchment to assess the contribution of different pollution sources

    Science.gov (United States)

    Desmet, Nele; Seuntjens, Piet

    2013-04-01

    Large river basins have multiple sources of pesticides and usually the pollution sources are spread over the entire catchment. The cumulative effect of pesticides entering the river system in upstream areas and the formation of persistent degradation products can compromise downstream water use e.g. raw water quality for drinking water abstractions. For assessments at catchment scale pesticide fluxes coming from different sources and sub basins need to be taken into account. To improve management strategies, a sound understanding of the sources, emission routes, transport, environmental fate and conversion of pesticides is needed. In the Netherlands, the Meuse river basin is an important source for drinking water production. The river suffers from elevated concentrations of glyphosate and aminomethylphosphonic acid (AMPA). For AMPA it is rather unclear to what extent the pollution is related to glyphosate degradation and what is the contribution of other sources, especial phosphonates in domestic and industrial waste water. Based on the available monitoring data only it is difficult to distinguish between AMPA sources in such a large river basin. This hampers interpretation and decision making for water quality management in the Meuse catchment. Here, application of water quality models is very useful to obtain complementary information and insights. Modelling allows accounting for temporal and spatial variability in discharge and concentrations as well as distinguishing the contribution from conversion processes. In this study, a model for the river Meuse was developed and applied to assess the contribution of tributary and transnational influxes, glyphosate degradation and other sources to the AMPA pollution.

  3. Factors associated with sources, transport, and fate of chloroform and three other trihalomethanes in untreated groundwater used for drinking water

    Science.gov (United States)

    Carter, Janet M.; Moran, Michael J.; Zogorski, John S.; Price, Curtis V.

    2012-01-01

    Multiple lines of evidence for indicating factors associated with the sources, transport, and fate of chloroform and three other trihalomethanes (THMs) in untreated groundwater were revealed by evaluating low-level analytical results and logistic regression results for THMs. Samples of untreated groundwater from wells used for drinking water were collected from 1996-2007 from 2492 wells across the United States and analyzed for chloroform, bromodichloromethane, dibromochloromethane, and bromoform by a low-level analytical method implemented in April 1996. Using an assessment level of 0.02 μg/L, chloroform was detected in 36.5% of public-well samples and 17.6% of domestic-well samples, with most concentrations less than 1 μg/L. Brominated THMs occurred less frequently than chloroform but more frequently in public-well samples than domestic-well samples. For both public and domestic wells, THMs occurred most frequently in urban areas. Logistic regression analyses showed that the occurrence of THMs was related to nonpoint sources such as urban land use and to point sources like septic systems. The frequent occurrence and concentration distribution pattern of THMs, as well as their frequent co-occurrence with other organic compounds and nitrate, all known to have anthropogenic sources, and the positive associations between THM occurrence and dissolved oxygen and recharge indicate the recycling of water that contains THMs and other anthropogenic contaminants.

  4. Modeling fate and transport of fecally-derived microorganisms at the watershed scale: State of the science and future opportunities.

    Science.gov (United States)

    Cho, Kyung Hwa; Pachepsky, Yakov A; Oliver, David M; Muirhead, Richard W; Park, Yongeun; Quilliam, Richard S; Shelton, Daniel R

    2016-09-01

    Natural waters serve as habitat for a wide range of microorganisms, a proportion of which may be derived from fecal material. A number of watershed models have been developed to understand and predict the fate and transport of fecal microorganisms within complex watersheds, as well as to determine whether microbial water quality standards can be satisfied under site-specific meteorological and/or management conditions. The aim of this review is to highlight and critically evaluate developments in the modeling of microbial water quality of surface waters over the last 10 years and to discuss the future of model development and application at the watershed scale, with a particular focus on fecal indicator organisms (FIOs). In doing so, an agenda of research opportunities is identified to help deliver improvements in the modeling of microbial water quality draining through complex landscape systems. This comprehensive review therefore provides a timely steer to help strengthen future modeling capability of FIOs in surface water environments and provides a useful resource to complement the development of risk management strategies to reduce microbial impairment of freshwater sources. PMID:27176652

  5. The Transport and Fate of Helium in Martensitic Steels at Fusion Relevant He/DPA Ratios and DPA Rates

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, Richard J.; Odette, George R.; Yamamoto, Takuya; Gelles, David S.; Miao, Pifeng; Oliver, Brian M.

    2007-08-01

    Understanding, modeling and managing the effects of He and displacement damage on microstructural evolution and property changes are primary objectives of fusion materials research. We recently implemented an approach for producing controlled He-to-dpa ratios under neutron irradiation using a novel α-implantation technique. Thin 1-4 µm NiAl coatings were deposited on Eurofer-97 TEM discs to produce a uniform He deposition zone of 6 to 8 µm. The test matrix is aimed at characterizing the transport, fate and consequences of He and He-to-dpa ratio variation on alloys with a wide range of starting microstructure. We explore the effect He-to-dpa ratio and temperature on the microstructure of conventionally processed Eurofer-97. Bubbles were found at all irradiation temperatures, with estimated maximum diameters of ~12, 6.9 and 1.4 nm at 500°C (~9 dpa and 372 appm He), 400°C (~3.9 dpa and 82 appm He) and 300°C (~3.9 dpa and 89 appm He), respectively.

  6. Anomalous transport in the crowded world of biological cells

    Science.gov (United States)

    Höfling, Felix; Franosch, Thomas

    2013-04-01

    A ubiquitous observation in cell biology is that the diffusive motion of macromolecules and organelles is anomalous, and a description simply based on the conventional diffusion equation with diffusion constants measured in dilute solution fails. This is commonly attributed to macromolecular crowding in the interior of cells and in cellular membranes, summarizing their densely packed and heterogeneous structures. The most familiar phenomenon is a sublinear, power-law increase of the mean-square displacement (MSD) as a function of the lag time, but there are other manifestations like strongly reduced and time-dependent diffusion coefficients, persistent correlations in time, non-Gaussian distributions of spatial displacements, heterogeneous diffusion and a fraction of immobile particles. After a general introduction to the statistical description of slow, anomalous transport, we summarize some widely used theoretical models: Gaussian models like fractional Brownian motion and Langevin equations for visco-elastic media, the continuous-time random walk model, and the Lorentz model describing obstructed transport in a heterogeneous environment. Particular emphasis is put on the spatio-temporal properties of the transport in terms of two-point correlation functions, dynamic scaling behaviour, and how the models are distinguished by their propagators even if the MSDs are identical. Then, we review the theory underlying commonly applied experimental techniques in the presence of anomalous transport like single-particle tracking, fluorescence correlation spectroscopy (FCS) and fluorescence recovery after photobleaching (FRAP). We report on the large body of recent experimental evidence for anomalous transport in crowded biological media: in cyto- and nucleoplasm as well as in cellular membranes, complemented by in vitro experiments where a variety of model systems mimic physiological crowding conditions. Finally, computer simulations are discussed which play an important

  7. Fate and transport of oil sand process-affected water into the underlying clay till: a field study.

    Science.gov (United States)

    Abolfazlzadehdoshanbehbazari, Mostafa; Birks, S Jean; Moncur, Michael C; Ulrich, Ania C

    2013-08-01

    The South Tailings Pond (STP) is a ~2300-ha tailing pond operated by Suncor Energy Inc. that has received oil sand process-affected (PA) water and mature fine tailings since 2006. The STP is underlain by a clay till, which is in turn underlain by the Wood Creek Sand Channel (WCSC). The sandy deposits of the WCSC provide greater geotechnical stability but could act as a potential flow pathway for PA water to migrate off site and into the Athabasca River. Preliminary modeling of the STP suggests that PA water from the pond will infiltrate into the underlying sand channel, but the extent and development of this impact is still poorly understood. Suncor Energy Inc. built interception wells and a cut-off-wall to control any potential seepage. Here we present the results of an investigation of the fate and transport of PA water in clay till underlying a 10 m × 10 m infiltration pond that was constructed on the southeastern portion of the STP. The geochemistry of pore water in the till underlying the infiltration pond was determined prior to filling with process-affected water (2008) and two years after the infiltration pond was filled with PA waters (2010). Pore water was analyzed for metals, cations, anions, and isotopes ((2)H and (18)O). The distribution of conservative tracers ((18)O and chloride) indicated migration of the PA waters to approximately 0.9 m, but the migrations of major ions and metals were significantly delayed relative to this depth. Uptake of Na and Mo and release of Ca, Mg, Mn, Ba, and Sr suggest that adsorption and ion exchange reactions are the foremost attenuation processes controlling inorganic solutes transport. PMID:23752067

  8. Source, transport and fate of soil organic matter inferred from microbial biomarker lipids on the East Siberian Arctic Shelf

    Science.gov (United States)

    Bischoff, Juliane; Sparkes, Robert B.; Doğrul Selver, Ayça; Spencer, Robert G. M.; Gustafsson, Örjan; Semiletov, Igor P.; Dudarev, Oleg V.; Wagner, Dirk; Rivkina, Elizaveta; van Dongen, Bart E.; Talbot, Helen M.

    2016-09-01

    The Siberian Arctic contains a globally significant pool of organic carbon (OC) vulnerable to enhanced warming and subsequent release by both fluvial and coastal erosion processes. However, the rate of release, its behaviour in the Arctic Ocean and vulnerability to remineralisation is poorly understood. Here we combine new measurements of microbial biohopanoids including adenosylhopane, a lipid associated with soil microbial communities, with published glycerol dialkyl glycerol tetraethers (GDGTs) and bulk δ13C measurements to improve knowledge of the fate of OC transported to the East Siberian Arctic Shelf (ESAS). The microbial hopanoid-based soil OC proxy R'soil ranges from 0.0 to 0.8 across the ESAS, with highest values nearshore and decreases offshore. Across the shelf R'soil displays a negative linear correlation with bulk δ13C measurements (r2 = -0.73, p = soil shows limited variation, whereas the BIT index shows a rapid decline moving away from the Lena River outflow channels. This reflects a balance between delivery and removal of OC from different sources. The good correlation between the hopanoid and bulk terrestrial signal suggests a broad range of hopanoid sources, both fluvial and via coastal erosion, whilst GDGTs appear to be primarily sourced via fluvial transport. Analysis of ice complex deposits (ICDs) revealed an average R'soil of 0.5 for the Lena Delta, equivalent to that of the Buor-Khaya Bay sediments, whilst ICDs from further east showed higher values (0.6-0.85). Although R'soil correlates more closely with bulk OC than the BIT, our understanding of the endmembers of this system is clearly still incomplete, with variations between the different East Siberian Arctic regions potentially reflecting differences in environmental conditions (e.g. temperature, pH), but other physiological controls on microbial bacteriohopanepolyol (BHP) production under psychrophilic conditions are as yet unknown.

  9. Fate and transport of oil sand process-affected water into the underlying clay till: a field study.

    Science.gov (United States)

    Abolfazlzadehdoshanbehbazari, Mostafa; Birks, S Jean; Moncur, Michael C; Ulrich, Ania C

    2013-08-01

    The South Tailings Pond (STP) is a ~2300-ha tailing pond operated by Suncor Energy Inc. that has received oil sand process-affected (PA) water and mature fine tailings since 2006. The STP is underlain by a clay till, which is in turn underlain by the Wood Creek Sand Channel (WCSC). The sandy deposits of the WCSC provide greater geotechnical stability but could act as a potential flow pathway for PA water to migrate off site and into the Athabasca River. Preliminary modeling of the STP suggests that PA water from the pond will infiltrate into the underlying sand channel, but the extent and development of this impact is still poorly understood. Suncor Energy Inc. built interception wells and a cut-off-wall to control any potential seepage. Here we present the results of an investigation of the fate and transport of PA water in clay till underlying a 10 m × 10 m infiltration pond that was constructed on the southeastern portion of the STP. The geochemistry of pore water in the till underlying the infiltration pond was determined prior to filling with process-affected water (2008) and two years after the infiltration pond was filled with PA waters (2010). Pore water was analyzed for metals, cations, anions, and isotopes ((2)H and (18)O). The distribution of conservative tracers ((18)O and chloride) indicated migration of the PA waters to approximately 0.9 m, but the migrations of major ions and metals were significantly delayed relative to this depth. Uptake of Na and Mo and release of Ca, Mg, Mn, Ba, and Sr suggest that adsorption and ion exchange reactions are the foremost attenuation processes controlling inorganic solutes transport.

  10. Flow Splitting with Fate Sharing in a Next Generation Transport Services Architecture

    CERN Document Server

    Iyengar, Janardhan

    2009-01-01

    The challenges of optimizing end-to-end performance over diverse Internet paths has driven widespread adoption of in-path optimizers, which can destructively interfere with TCP's end-to-end semantics and with each other, and are incompatible with end-to-end IPsec. We identify the architectural cause of these conflicts and resolve them in Tng, an experimental next-generation transport services architecture, by factoring congestion control from end-to-end semantic functions. Through a technique we call "queue sharing", Tng enables in-path devices to interpose on, split, and optimize congestion controlled flows without affecting or seeing the end-to-end content riding these flows. Simulations show that Tng's decoupling cleanly addresses several common performance problems, such as communication over lossy wireless links and reduction of buffering-induced latency on residential links. A working prototype and several incremental deployment paths suggest Tng's practicality.

  11. Fate and transport of glyphosate and aminomethylphosphonic acid in surface waters of agricultural basins

    Science.gov (United States)

    Gregoire, Caroline; Capel, Paul D.; Coupe, Richard H.; Kalkhoff, Stephen J.

    2011-01-01

    BACKGROUND: Glyphosate [N-(phosphonomethyl)glycine] is a herbicide used widely throughout the world in the production of many crops and is heavily used on soybeans, corn and cotton. Glyphosate is used in almost all agricultural areas of the United States, and the agricultural use of glyphosate has increased from less than 10 000 Mg in 1992 to more than 80 000 Mg in 2007. The greatest intensity of glyphosate use is in the midwestern United States, where applications are predominantly to genetically modified corn and soybeans. In spite of the increase in usage across the United States, the characterization of the transport of glyphosate and its degradate aminomethylphosphonic acid (AMPA) on a watershed scale is lacking.

  12. Fate and Transport of 17β-estradiol Beneath Animal Waste Holding Ponds

    Science.gov (United States)

    Gibson, L. A.; Tyner, J. S.; Hawkins, S. A.; Lee, J.; Buchanan, J. R.

    2011-12-01

    Steroidal hormones, such as 17β-estradiol (E2), are prevalent in animal waste and are a common subject of study due to potential stream and groundwater contamination. These particular hormones are labeled as Endocrine Disrupting Chemicals (EDCs) because of their developmental effects in reptiles and amphibians. Dairy waste at concentrated animal feeding operations is typically stored in a pond that is regulated by law to include an underlying soil liner with a minimal hydraulic conductivity to limit leaching beneath the pond, yet some studies have traced stream and groundwater contamination to these ponds. Previous studies have shown that the soil underlying earthen ponds are always unsaturated. This increases the pore water velocity relative to a given flux, which itself is dictated almost entirely by an organic seal that forms at the bottom of a waste pond. This increased velocity results in more rapid transport and less retention time within the vadose zone where E2 could biodegrade into its daughter product, estrone (E1). And since the soil is unsaturated and therefore has a negative pressure, preferential flow should not serve as a method of transport. On the contrary, E2 and E1 may sorb to mobile colloids increasing their mobility. This study will evaluate the use of biochar, an increasingly common activated carbon source, as a soil liner amendment. Biochar has a specific surface area that can exceed 1,500 m2/g and is high in organic matter, which E2 sorbs to strongly. The biochar amendment should be most effective and enduring as a layer located at the bottom of the soil liner so that the leachate has been treated by the soil prior to contact. Another proposed amendment technique is to uniformly mix the biochar within the soil liner to increase the leachate contact time with the biochar, but realistically could prove to be too costly and energy-intensive. Field and laboratory studies were conducted to analyze hormone persistence and transport processes and

  13. Modeling Fate and Transport of Chloride from Deicers in Urban Floodplains: Implications for Urban Planning

    Science.gov (United States)

    Ledford, S. H.; Lautz, L.

    2015-12-01

    Road salting in urban areas of the northeastern United States increases chloride concentrations in urban streams. Groundwater storage of saline road runoff results in increased surface water chloride concentrations through time, even in non-winter months. Stream-groundwater (SW-GW) interactions promote buffering of large seasonal swings in stream chloride concentrations, resulting in lower surface water chloride in winter and higher concentrations in summer, relative to streams hydrologically disconnected from riparian floodplains. However, the hydrogeologic processes controlling salt storage and transport in urban floodplain aquifers have not been fully investigated. We developed a 3D numerical groundwater flow and solute transport model of an urban floodplain in Syracuse, New York, using MODFLOW and MT3DMS. We ran the model for 1 year, calibrating to three conditions: water table elevations along a riparian transect, measurements of net groundwater flux to the stream along the 500-m reach, and chloride concentrations in groundwater through time in riparian wells. Chloride enters the riparian aquifer via three pathways: hillslope groundwater discharge, hyporheic exchange, and groundwater recharge during overbank flooding events. Winter overbank flooding events are the primary source of chloride to floodplain sediments. While hillslope groundwater discharge results in relatively uniform chloride through time in high conductivity units, surficial floodplain sediments with lower conductivity have high chloride concentrations from winter overbank flood events. When compared to road salt application rates (up to 20 tons of salt per lane kilometer per year), the 0.013 km2 floodplain holds only a tiny fraction of chloride applied in a watershed (>100 km of road in the watershed). To promote riparian aquifer storage of road salt and buffering of stream chloride concentrations, urban planners should design urban floodplains for frequent winter flooding events, and allow

  14. Atmospheric transport, deposition, and fate of triazine herbicides and their metabolites in pristine areas at Isle Royale National Park

    Science.gov (United States)

    Thurman, E.M.; Cromwell, A.E.

    2000-01-01

    Trace concentrations of triazine herbicides, used in the Midwestern United States, are being transported atmospherically hundreds of kilometers and deposited by precipitation onto pristine areas, such as Isle Royale National Park (Lake Superior). Atrazine, deethylatrazine, deisopropylatrazine, and cyanazine were detected in Isle Royale rainfall from mid-May to early July (1992-1994) at concentrations of less than 0.005 to 1.8 ??g/L. Analysis of predominant wind direction indicated that the herbicides originated from the upper Midwestern United States. The annual mass of herbicides deposited by rainfall varied between years, from 13.4 ??g/m2/yr for 1992, 3.7 ??g/m2/yr for 1993, and 54 ??g/m2/yr for 1994. Atrazine and deethylatrazine were found also in concentrations of less than 5-22 ng/L in lakes across Isle Royale. Concentrations of atrazine in the surface layer of the lakes increased during deposition periods and decreased later in the year. The fate of triazines in shallow lakes suggests faster degradation and shorter half-lives, while deeper lakes have residence times for atrazine that may exceed 10 years.Trace concentrations of triazine herbicides, used in the Midwestern United States, are being transported atmospherically hundreds of kilometers and deposited by precipitation onto pristine areas, such as Isle Royale National Park (Lake Superior). Atrazine, deethylatrazine, deisopropylatrazine, and cyanazine were detected in Isle Royale rainfall from mid-May to early July (1992-1994) at concentrations of less than 0.005 to 1.8 ??g/L. Analysis of predominant wind direction indicated that the herbicides originated from the upper Midwestern United States. The annual mass of herbicides deposited by rainfall varied between years, from 13.4 ??g/m2/yr for 1992, 3.7 ??g/m2/yr for 1993, and 54 ??g/m2/yr for 1994. Atrazine and deethylatrazine were found also in concentrations of less than 5-22 ng/L in lakes across Isle Royale. Concentrations of atrazine in the surface

  15. Integration of biogenic emissions in environmental fate, transport, and exposure systems

    Science.gov (United States)

    Efstathiou, Christos I.

    Biogenic emissions make a significant contribution to the levels of aeroallergens and secondary air pollutants such as ozone. Understanding major factors contributing to allergic airway diseases requires accurate characterization of emissions and transport/transformation of biogenic emissions. However, biogenic emission estimates are laden with large uncertainties. Furthermore, the current biogenic emission estimation models use low-resolution data for estimating land use, vegetation biomass and VOC emissions. Furthermore, there are currently no established methods for estimating bioaerosol emissions over continental or regional scale, which can impact the ambient levels of pollent that have synergestic effects with other gaseous pollutants. In the first part of the thesis, an detailed review of different approaches and available databases for estimating biogenic emissions was conducted, and multiple geodatabases and satellite imagery were used in a consistent manner to improve the estimates of biogenic emissions over the continental United States. These emissions represent more realistic, higher resolution estimates of biogenic emissions (including those of highly reactive species such as isoprene). The impact of these emissions on tropospheric ozone levels was studied at a regional scale through the application of the USEPA's Community Multiscale Air Quality (CMAQ) model. Minor, but significant differences in the levels of ambient ozone were observed. In the second part of the thesis, an algorithm for estimating emissions of pollen particles from major allergenic tree and plant families in the United States was developed, extending the approach for modeling biogenic gas emissions in the Biogenic Emission Inventory System (BEIS). A spatio-temporal vegetation map was constructed from different remote sensing sources and local surveys, and was coupled with a meteorological model to develop pollen emissions rates. This model overcomes limitations posed by the lack of

  16. Fate and transport of lignin in the soil-water continuum

    Science.gov (United States)

    Williams, J. S.; Dungait, J.; Bol, R.; Abbott, G. D.

    2011-12-01

    Soils have been identified as having the potential to store greater amounts of carbon (C) in soil organic matter (SOM) through appropriate land uses and management practices to increase the input of recalcitrant components of organic matter, such as lignin. Lignin is allocated to the 'slow' soil C pools with residence times between 15 - 100 yrs. Lignin is 30% of the C fixed by plants and is an important C input to soils. However, Recent research has shown that the configuration of lignin monomers within the lignin macromolecule is not random [1], that lignin degradation is monomer specific [2], and that lignin is preferentially degraded relative to the bulk SOM [3], thereby questioning the role of lignin in C sequestration. Although guaiacyl (G) and syringyl (S) lignin monomers have been identified in fresh, estuarine, and marine waters [4], the initial forms to which lignin is degraded into water-transportable products and lost from the soil C reservoir are not known. The aims of this project are to (i) identify and quantify the lignin-derived products entering the soluble phase in soils, and (ii) determine the rate of lignin degradation into water-soluble components, and their rate of transport through soil. In experiment 1 we tested the best approach to extract and analyse dissolved lignin from outflows from grassland and woodland sites. C18 solid phase extraction (SPE) or freeze-drying (FD) was used to isolate water-borne lignin monomers. Gas chromatography-mass spectrometry (GC-MS) of trimethylsilyl (TMS) derivatives or tetramethylammonium hydroxide (TMAH) thermochemolysis was used to analyse the samples. In a subsequent experiment, we allowed leaves from different vegetation types (Lolium perenne, Ranunculus repens, Fraxinus excelsior, Quercus robur), corresponding to the vegetation at our initial sites in Experiment 1, to degrade in soil lysimeters for 1.5 years to determine the rates of decomposition of different plant material and dominant form of lignin

  17. Long range transport and fate of a stratospheric volcanic cloud from Soufriere Hills volcano, Montserrat

    Directory of Open Access Journals (Sweden)

    A. J. Prata

    2007-04-01

    Full Text Available Volcanic eruptions emit gases, ash particles and hydrometeors into the atmosphere, occasionally reaching great heights to reside in the stratospheric overworld where they affect the radiative balance of the atmosphere and the earth's climate. Here we use satellite measurements and a Lagrangian particle dispersion model to determine the mass loadings, vertical penetration, horizontal extent, dispersion and transport of volcanic gases and particles in the stratosphere from the volcanic cloud emitted during the 20 May 2006 eruption of Soufriere Hills volcano, Montserrat, West Indies. Infrared, ultraviolet and microwave radiation measurements from two polar orbiters are used to quantify the gases and particles, and track the movement of the cloud for 23 days, over a distance of ~18 000 km. Approximately, 0.1±0.01 Tg(S was injected into the stratosphere in the form of SO2: the largest single sulfur input to the stratosphere in 2006. Microwave Limb Sounder measurements indicate an enhanced mass of HCl of ~0.003–0.01 Tg. Geosynchronous satellite data reveal the rapid nature of the stratospheric injection and indicate that the eruption cloud contained ~2 Tg of ice, with very little ash reaching the stratosphere. These new satellite measurements of volcanic gases and particles can be used to test the sensitivity of climate to volcanic forcing and assess the impact of stratospheric sulfates on climate cooling.

  18. Modelling origin and transport fate of waste materials on the south-eastern Adriatic coast (Croatia

    Directory of Open Access Journals (Sweden)

    M. Tudor

    2014-12-01

    Full Text Available The south-eastern parts of the Adriatic Sea coastline were severely polluted by large amounts of accumulated waste material in the second half of November 2010. The waste, reported by major news agencies, accumulated dominantly during 21 November 2010 by favourable wind – ocean current transport system. In the study we analysed meteorological and oceanographic conditions that lead to the waste deposition using available in situ measurements, remote sensing data as well numerical models of the ocean and the atmosphere. The measured data reveal that an intensive rainfall event from 7 till 10 November 2010, over the parts of Montenegro and Albania, was followed by a substantial increase of the river water levels indicating flash floods that possibly splashed the waste material into a river and after to the Adriatic Sea. In order to test our hypothesis we set a number of numerical drifter experiments with trajectories initiated off the coast of Albania during the intensive rainfall events following their faith in space and time. One of the numerical drifter trajectory experiment resulted with drifters reached right position (south-eastern Adriatic coast and time (exactly by the time the waste was observed when initiated on 00:00 and 12:00 UTC of 10 November 2010 during the mentioned flash flood event.

  19. Complex Systems Science for Subsurface Fate and Transport Report from the August 2009 Workshop

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-03-01

    in models can provide a basis for testing hypotheses, guiding experiment design, integrating scientific knowledge on multiple environmental systems into a common framework, and translating this information to support informed decision making and policies. Subsurface behavior typically has been investigated using reductionist, or bottom-up approaches. In these approaches, mechanisms of small-scale processes are quantified, and key aspects of their behaviors are moved up to the prediction scale using scaling laws and models. Reductionism has and will continue to yield essential and comprehensive understanding of the molecular and microscopic underpinnings of component processes. However, system-scale predictions cannot always be made with bottom-up approaches because the behaviors of subsurface environments often simply do not result from the sum of smaller-scale process interactions. Systems exhibiting such behavior are termed complex and can range from the molecular to field scale in size. Complex systems contain many interactive parts and display collective behavior including emergence, feedback, and adaptive mechanisms. Microorganisms - key moderators of subsurface chemical processes - further challenge system understanding and prediction because they are adaptive life forms existing in an environment difficult to observe and measure. A new scientific approach termed complex systems science has evolved from the critical need to understand and model these systems, whose distinguishing features increasingly are found to be common in the natural world. In contrast to reductionist approaches, complexity methods often use a top-down approach to identify key interactions controlling diagnostic variables at the prediction scale; general macroscopic laws controlling system-scale behavior; and essential, simplified models of subsystem interactions that enable prediction. This approach is analogous to systems biology, which emphasizes the tight coupling between

  20. Fate and Transport of Fire-Born Particles in Porous Media

    Directory of Open Access Journals (Sweden)

    Prabhakar Sharma

    2015-12-01

    Full Text Available A variety of hazardous substances may be generated from the burning materials during fire extinguishing operations, depending on the location, type, and place of the fire. As a result, the fire-extinguishing water may act as a carrier for these nano- and micro-sized fire-born particles, including various types of associated contaminants, and may cause contamination of soil and groundwater resources. While airborne particles from fires have been studied, it is currently not well known what types of nano- and micro-sized contaminants are typically carried by the fire-extinguishing water and how these contaminants can be transported in the natural environment. The main purpose of this study was to increase the understanding about the occurrence and physical and chemical properties of nanoparticles commonly found in discharge water from fire extinguishing operations. The current study was based on collection of original samples from a fire location. A detailed characterization of the particles present in the extinguishing water was performed including both quantification of contaminants associated with the particles (such as metals and polycyclic aromatic hydrocarbons (PAHs as well as measurement of properties related to the mobility of these particles through porous media. Such mobility properties include size distributions of the particles and the porous media, surface charges and solution chemistry. Results indicate that metals and PAHs are present in both finer and relatively larger fire-born particles. The particles larger than 11 μm were not mobile in porous media. The mobility of the finer particles (<11 μm was generally high but was dependent on the solution chemistry. Low mobility of large particles in porous media indicates that a large amount of the contamination can likely be trapped in the top soil layer even though the fire extinguishing water infiltrates.

  1. Fate and transport of monensin in the presence of nonionic surfactant Brij35 in soil.

    Science.gov (United States)

    ElSayed, Eman M; Prasher, Shiv O

    2014-08-15

    As fresh water is a limited resource in many parts of the world, the use of wastewater for irrigation has become an important alternative. Therefore, many countries facing a water deficit, use partially treated, or even untreated, wastewater. This may increase the input of many contaminants into the environment. In the present study, we investigated the effect of using surfactant rich water in irrigation on the mobility of the most commonly-used veterinary antibiotic, monensin. Nine PVC lysimeters, 1.0m long×0.45 m diameter, were packed with a sandy soil to a bulk density of 1.35 Mg m(-3). Cattle manure, containing monensin, was applied at the surface of the lysimeters at the recommended rate of 10t/ha. Each of three aqueous Brij 35 solutions, 0, 0.5 and 5 g L(-1), was applied to the lysimeters in triplicate. Over a 90 day period, soil and leachate samples were collected and analyzed. The results of the laboratory sorption experiment showed that when the nonionic surfactant Brij 35 is present, the sorption coefficient of monensin was reduced significantly from 120.22 mL g(-1) in the aqueous medium to 112.20, 100 and 63.09 mL g(-1) with Brij35 concentrations of 0.25, 2.5 and 5 g L(-1), respectively. The lysimeter results indicated a significant downward movement of monensin at depths of 60 cm in the soil profile and leachate in the presence of the surfactant. Thus, the continuous use of poor quality water could influence the transport of monensin in agricultural soils, and consequently, pose a risk for groundwater pollution. PMID:24887190

  2. Transport and fate of mercury under different hydrologic regimes in polluted stream in mining area

    Institute of Scientific and Technical Information of China (English)

    Yan Lin; Thorjφrm Larssen; Rolf D. Vogt; Xinbin Feng; Hua Zhang

    2011-01-01

    Seepage from Hg mine wastes and calcines contains high concentrations of mercury (Hg).Hg pollution is a major environmental problem in areas with abandoned mercury mines and retorting units.This study evaluates factors, especially the hydrological and sedimentary variables, governing temporal and spatial variation in levels and state of mercury in streams impacted by Hg contaminated runoff.Samples were taken during different flow regimes in the Wanshan Hg mining area in Guizhou Province, China.In its headwaters the sampled streams/rivers pass by several mine wastes and calcines with high concentration of Hg.Seepage causes serious Hg contamination to the downstream area.Concentrations of Hg in water samples showed significant seasonal variations.Periods of higher flow showed high concentrations of total Hg (THg) in water due to more particles being re-suspended and transported.The concentrations of major anions (e.g., CI-, F-, NO3- and 8042-) were lower during higher flow due to dilution.Due to both sedimentation of particles and dilution from tributaries the concentration of THg decreased from 2100 ng/L to background levels (< 50 ng/L) within 10 km distance downstream.Sedimentation is the main reason for the fast decrease of the concentration, it accounts for 69% and 60%for higher flow and lower flow regimes respectively in the upper part of the stream.Speciation calculation of the dissolved Hg fraction (DHg) (using Visual MINTEQ) showed that Hg(OH)2 associated with dissolved organic matter is the main form of Hg in dissolved phase in surface waters in Wanshan (over 95%).

  3. Modelling impact of climate change on atmospheric transport and fate of persistent organic pollutants in the Arctic

    Directory of Open Access Journals (Sweden)

    K. M. Hansen

    2015-03-01

    Full Text Available The Danish Eulerian Hemispheric Model (DEHM was applied to investigate how projected climate changes will affect the atmospheric transport of 13 persistent organic pollutants (POPs to the Artic and their environmental fate within the Arctic. Two sets of simulations were performed, one with initial environmental concentrations from a 20 year spin-up simulation and one with initial environmental concentrations set to zero. Each set of simulations consisted of two ten-year time slices representing the present (1990–2000 and future (2090–2100 climate conditions. The same POP emissions were applied in all simulations to ensure that the difference in predicted concentrations for each set of simulations only arises from the difference in climate input. DEHM was driven using meteorological input from the global circulation model, ECHAM/MPI-OM, simulating the SRES A1B climate scenario. Under the applied climate and emission scenarios, the total mass of all compounds was predicted to be up to 20% higher across the Northern Hemisphere. The mass of HCHs within the Arctic was predicted to be up to 39% higher, whereas the change in mass of the PCBs was predicted to range from 14% lower to 17% higher depending on the congener and the applied initial environmental concentrations. The results of this study also indicate that contaminants with no or a short emission history will be more rapidly transported to and build up in the arctic environment in a future warmer climate. The process that dominates the environmental behaviour of POPs in the Arctic under a future warmer climate scenario is the shift in mass of POPs from the surface media to the atmosphere induced by the higher mean temperature. This is to some degree counteracted by higher degradation rates also following the higher mean temperature. The more dominant of these two processes depend on the physical-chemical properties of the compounds. Previous model studies have predicted that the effect of

  4. Fate and transport of some selected PhACs in a river receiving a high load of treated sewage

    Science.gov (United States)

    Bendz, D.; Ginn, T. R.; Paxeus, N.

    2003-04-01

    Pharmaceutical active compounds (PhACs) have lately been acknowledged to constitute a risk for humans and for the terrestrial and aquatic environment. Human and veterinary applications are the main sources of PhACs in the environment and the major pathway are excretion and discharge to the environment. Sewage treatment plants (STPs) play a crucial role for the introduction of the human PhACs in the environment through its removal efficiency and by separating these compounds into two exposure pathways associated with the aquatic and the solid (sludge) phase, respectively. Actually, STPs are recognized as being the main point discharge sources of human PhACs to the aquatic environment. In this study the fate and transport of a selected human PhACs belonging to different therapeutic classes (NSAIDs- non-steroidal antiinflamatory drugs, lipid regulators, antiepileptics, antibiotics and &beta-blockers) are investigated in a small river in the very south of Sweden receiving a high load of treated wastewater. In addition to the PhACs, triclosan (commonly used biocide) was included in this study. Water samples were taken of incoming and outgoing wastewater from the treatment plant, at the effluent in the river, and along the river up to 8 kilometers downstream were the river flows into the sea. After enrichment by solid-phase extraction the compounds were analyzed using GC-MS (methylated derivatives) or LC-MS/MS. In addition to the target compounds a screening analysis of the extracts revealed the presence of other wastewater related pollutants (caffeine, flame retardants, antioxidants). Several of the investigated substances demonstrate a surprising persistence in the aquatic environment. This emphasizes the need for a broader view on the concept of persistence by taking into account the recharge/loading rate in addition to removal mechanisms; transformation, volatility and physical sequestration by solids and the influence of different environmental media (Soil organic

  5. Interrogating the Role of Receptor-Mediated Mechanisms: Biological Fate of Peptide-Functionalized Radiolabeled Gold Nanoparticles in Tumor Mice.

    Science.gov (United States)

    Silva, Francisco; Zambre, Ajit; Campello, Maria Paula Cabral; Gano, Lurdes; Santos, Isabel; Ferraria, Ana Maria; Ferreira, Maria João; Singh, Amolak; Upendran, Anandhi; Paulo, António; Kannan, Raghuraman

    2016-04-20

    To get a better insight on the transport mechanism of peptide-conjugated nanoparticles to tumors, we performed in vivo biological studies of bombesin (BBN) peptide functionalized gold nanoparticles (AuNPs) in human prostate tumor bearing mice. Initially, we sought to compare AuNPs with thiol derivatives of acyclic and macrocyclic chelators of DTPA and DOTA types. The DTPA derivatives were unable to provide a stable coordination of (67)Ga, and therefore, the functionalization with the BBN analogues was pursued for the DOTA-containing AuNPs. The DOTA-coated AuNPs were functionalized with BBN[7-14] using a unidentate cysteine group or a bidentate thioctic group to attach the peptide. AuNPs functionalized with thioctic-BBN displayed the highest in vitro cellular internalization (≈ 25%, 15 min) in gastrin releasing peptide (GRP) receptor expressing cancer cells. However, these results fail to translate to in vivo tumor uptake. Biodistribution studies following intravenous (IV) and intraperitoneal (IP) administration of nanoconjugates in tumor bearing mice indicated that the presence of BBN influences to some degree the biological profile of the nanoconstructs. For IV administration, the receptor-mediated pathway appears to be outweighed by the EPR effect. By contrast, in IP administration, it is reasoned that the GRPr-mediated mechanism plays a role in pancreas uptake. PMID:27003101

  6. Source, transport and fate of soil organic matter inferred from microbial biomarker lipids on the East Siberian Arctic Shelf

    Science.gov (United States)

    Bischoff, Juliane; Sparkes, Robert B.; Doğrul Selver, Ayça; Spencer, Robert G. M.; Gustafsson, Örjan; Semiletov, Igor P.; Dudarev, Oleg V.; Wagner, Dirk; Rivkina, Elizaveta; van Dongen, Bart E.; Talbot, Helen M.

    2016-09-01

    The Siberian Arctic contains a globally significant pool of organic carbon (OC) vulnerable to enhanced warming and subsequent release by both fluvial and coastal erosion processes. However, the rate of release, its behaviour in the Arctic Ocean and vulnerability to remineralisation is poorly understood. Here we combine new measurements of microbial biohopanoids including adenosylhopane, a lipid associated with soil microbial communities, with published glycerol dialkyl glycerol tetraethers (GDGTs) and bulk δ13C measurements to improve knowledge of the fate of OC transported to the East Siberian Arctic Shelf (ESAS). The microbial hopanoid-based soil OC proxy R'soil ranges from 0.0 to 0.8 across the ESAS, with highest values nearshore and decreases offshore. Across the shelf R'soil displays a negative linear correlation with bulk δ13C measurements (r2 = -0.73, p = < 0.001). When compared to the GDGT-based OC proxy, the branched and isoprenoid tetraether (BIT) index, a decoupled (non-linear) behaviour on the shelf was observed, particularly in the Buor-Khaya Bay, where the R'soil shows limited variation, whereas the BIT index shows a rapid decline moving away from the Lena River outflow channels. This reflects a balance between delivery and removal of OC from different sources. The good correlation between the hopanoid and bulk terrestrial signal suggests a broad range of hopanoid sources, both fluvial and via coastal erosion, whilst GDGTs appear to be primarily sourced via fluvial transport. Analysis of ice complex deposits (ICDs) revealed an average R'soil of 0.5 for the Lena Delta, equivalent to that of the Buor-Khaya Bay sediments, whilst ICDs from further east showed higher values (0.6-0.85). Although R'soil correlates more closely with bulk OC than the BIT, our understanding of the endmembers of this system is clearly still incomplete, with variations between the different East Siberian Arctic regions potentially reflecting differences in environmental

  7. Theoretical Analysis of the Influence of Process Parameters on Pathogen Transport and Fate in a Recreational Beach

    Science.gov (United States)

    Liu, L.; Fu, X.

    2010-12-01

    The US has very long shorelines (95,471 miles) contributing remarkable yearly revenue to the country by providing numerous recreational beaches. The beaches of both inland lakes and marine regions must be closed when the level of waterborne pathogens indicated by fecal indicator bacteria (FIB) including total coliform (TC), fecal coli form (FC, or Escherichia coli, E. coli) and Enterococcus exceed microbial water quality standards. Beach closures are of mounting concern to beach managers and the public due to the increasing risk to human health from waterborne pathogens. Monitoring FIB with laboratory analysis usually takes at least 18 hours during which beach goers may have been unintentionally exposed to the contaminated water. Therefore a water quality model to quickly and precisely forecast FIB has been a very effective tool for beach management to help beach managers in making decisions if beaches are safe enough to open to the public. The fate and transport of pathogens in the surf-zone of a beach area is a complex process involving various factors of hydrodynamics, hydrology, chemistry, microbiology. These factors including dispersion coefficient, wind velocity, particle settling velocity, fraction of bacteria attached, solar insolation, discharges to the beach, geometry of the beach, etc, are the essential components for a mechanistic model to describe the inactivation of FIB. To better understand the importance of these factors and their roles in impacting inactivation, transport and removal of FIB is extremely important to enhance the effectiveness and preciseness of a predictive model. The aim of this paper is to report the sensitivity analysis results of these factors in the surf zone of a creational beach using a verified water quality model system. The relative importance of these parameters is being ranked. For instance, the current sensitivity analysis shows that sunlight insolation has greater impact on pathogen inactivation than water temperature

  8. A review of oil, dispersed oil and sediment interactions in the aquatic environment: influence on the fate, transport and remediation of oil spills.

    Science.gov (United States)

    Gong, Yanyan; Zhao, Xiao; Cai, Zhengqing; O'Reilly, S E; Hao, Xiaodi; Zhao, Dongye

    2014-02-15

    The 2010 Deepwater Horizon oil spill has spurred significant amounts of researches on fate, transport, and environmental impacts of oil and oil dispersants. This review critically summarizes what is understood to date about the interactions between oil, oil dispersants and sediments, their roles in developing oil spill countermeasures, and how these interactions may change in deepwater environments. Effects of controlling parameters, such as sediment particle size and concentration, organic matter content, oil properties, and salinity on oil-sediment interactions are described in detail. Special attention is placed to the application and effects of oil dispersants on the rate and extent of the interactions between oil and sediment or suspended particulate materials. Various analytical methods are discussed for characterization of oil-sediment interactions. Current knowledge gaps are identified and further research needs are proposed to facilitate sounder assessment of fate and impacts of oil spills in the marine environment.

  9. Impacts of biological diversity on sediment transport in streams

    Science.gov (United States)

    Albertson, L. K.; Cardinale, B. J.; Sklar, L. S.

    2012-12-01

    Over the past decade, an increasing number of studies have shown that biological structures (e.g. plant roots) have large impacts on sediment transport, and that physical models that do not incorporate these biological impacts can produce qualitatively incorrect predictions. But while it is now recognized that biological structures influence sediment transport, work to date has focused primarily on the impacts of individual, usually dominant, species. Here, we ask whether competitive interactions cause multi-species communities to have fundamentally different impacts on sediment mobility than single-species systems. We use a model system with caddisfly larvae, which are insects that live in the benthic habitat of streams where they construct silken catchnets across pore spaces between rocks to filter food particles. Because caddisflies can reach densities of 1,000s per m2 with each larva spinning hundreds of silken threads between rocks, studies have shown that caddisflies reduce the probability of bed movement during high discharge events. To test whether streams with multiple species of caddisfly are stabilized any differently than single-species streams, we manipulated the presence or absence of two common species (Ceratopsyche oslari, Arctopsyche californica) in substrate patches (0.15 m2) in experimental stream channels (50-m long x 1-m wide) with fully controlled hydrology at the Sierra Nevada Aquatic Research Laboratory. This experiment was designed to extend the scale of previous laboratory mesocosm studies, which showed that critical shear stress is 31% higher in a multi-species flume mesocosm compared to a single-species mesocosm. Under these more realistic field conditions, we found that critical shear stress was, on average, 30% higher in streams with caddisflies vs. controls with no caddisflies. However, no differences were detected between treatments with 2 vs. 1 species. We hypothesize that the minimal effect of diversity on critical shear stress

  10. Biological degradation of triclocarban and triclosan in a soil under aerobic and anaerobic conditions and comparison with environmental fate modelling

    International Nuclear Information System (INIS)

    Triclocarban and triclosan are two antimicrobial agents widely used in many personal care products. Their biodegradation behaviour in soil was investigated by laboratory degradation experiments and environmental fate modelling. Quantitative structure-activity relationship (QSAR) analyses showed that triclocarban and triclosan had a tendency to partition into soil or sediment in the environment. Fate modelling suggests that either triclocarban or triclosan 'does not degrade fast' with its primary biodegradation half-life of 'weeks' and ultimate biodegradation half-life of 'months'. Laboratory experiments showed that triclocarban and triclosan were degraded in the aerobic soil with half-life of 108 days and 18 days, respectively. No negative effect of these two antimicrobial agents on soil microbial activity was observed in the aerobic soil samples during the experiments. But these two compounds persisted in the anaerobic soil within 70 days of the experimental period. - Triclocarban and triclosan can be degraded by microbial processes in aerobic soil, but will persist in anaerobic soil

  11. Gasoline ether oxygenate occurrence in Europe, and a review of their fate and transport characteristics in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Stupp, D.; Gass, M.; Leiteritz, H. [Dr. Stupp Consulting DSC, Tauw, Bergisch Gladbach (Germany); Pijls, C. [TAUW, Apeldoorn (Netherlands); Thornton, S. [University of Sheffield, Sheffield (United Kingdom); Smith, J.; Dunk, M.; Grosjean, T.; Den Haan, K. [CONCAWE, Brussels (Belgium)

    2012-06-15

    Ether oxygenates are added to certain gasoline (petrol) formulations to improve combustion efficiency and to increase the octane rating. In this report the term gasoline ether oxygenates (GEO) refers collectively to methyl tertiary butyl ether (MTBE), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME), diisopropyl ether (DIPE), tertiary amyl ethyl ether (TAEE), tertiary hexyl methyl ether (THxME), and tertiary hexyl ethyl ether (THxEE), as well as the associated tertiary butyl alcohol (TBA). This report presents newly collated data on the production capacities and use of MTBE, ETBE, TAME, DIPE and TBA in 30 countries (27 EU countries and Croatia, Norway and Switzerland) to inform continued and effective environmental management practices for GEO by CONCAWE members. The report comprises data on gasoline use in Europe that were provided by CONCAWE and obtained from the European Commission. Furthermore Societe Generale de Surveillance (SGS) provided detailed analytical data (more than 1,200 sampling campaigns) on the GEO composition of gasoline in European countries in the period 2000-2010. Another major aspect of this report is the investigation of GEO distribution in groundwater, drinking water, surface water, runoff water, precipitation (rain/snow) and air in the European environment. Apart from the general sources of literature for the study, local environmental authorities and institutes in the 30 European countries have been contacted for additional information. Finally, a review of the international literature on GEO natural attenuation processes was undertaken with a focus on international reports and peer-reviewed scientific publications to give an overview on the known fate, transport and degradation mechanisms of GEO in the subsurface, to inform risk-management strategies that may rely on natural attenuation processes. The literature reveals that all GEO compounds used in fuels are highly water soluble and weakly retarded by aquifer

  12. Sediment transport modelling in the Gulf of Lion with the perspective of studying the fate of radionuclides originated by the Rhone River

    International Nuclear Information System (INIS)

    Among the various contaminants introduced in the environment, artificial radionuclides appear particularly important to consider because of their chemical toxicity and / or of their radio-toxicity. Some radionuclides present a high affinity with particles so that the study of the sediment dynamics is a useful preliminary to the study of their dispersion on the open sea. This thesis is focused on the fate of sediments in the Gulf of Lion (NW Mediterranean sea) and in particular on the impact of the Rhone River, which is the main source of particulate matter in the Gulf of Lion. In order to study the sediment transport mechanisms on various space and time scales, this thesis is based on mathematical modelling. The hydro-sedimentary model set up in the Gulf of Lion, which takes into account the gathered effect of waves and currents, was supported by recent hydro-sedimentary data analyses. CARMA (winter 2006/2007) and SCOPE (winter 2007/2008) experiments were used to better understand the physical processes which control the sediment transport on the Rhone pro-delta and to validate the model. The period of the centennial Rhone River flood of December 2003 was also simulated in order to determine the impact of such extreme events on the fate of sediments. Both observations and simulations of the studied periods highlight the high capacity of erosion and transport induced by south-eastern storms on the pro-delta

  13. Task 23 - field studies of the occurrence, transport, and fate of mercury at natural gas industry sites. Topical report, May 1, 1992--December 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Sorensen, J.A.; Harju, J.A.; Kuehnel, V.; Charlton, D.S.

    1998-12-31

    The objective of this research project is to define the occurrence, transport, and fate of mercury in air, water, and soil at natural gas production sites that had been instrumented with mercury-based gas flowmeters in the past. The primary focus of this research was initially on determining the potential for mercury contamination in groundwater at these sites. The scope was later broadened to include determinations of the spatial distribution of mercury in soil. Air concentrations were determined solely as a health and safety routine.

  14. Processes influencing the transport and fate of contaminated sediments in the coastal ocean: Boston Harbor and Massachusetts Bay

    Science.gov (United States)

    Bothner, Michael H.; Butman, Bradford

    2007-01-01

    Most of the major urban centers of the United States including Boston, New York, Washington, Chicago, New Orleans, Miami, Los Angeles, San Francisco, and Seattle—are on a coast (fig. 1.1). All of these cities discharge treated sewage effluent into adjacent waters. In 2000, 74 percent of the U.S. population lived within 200 kilometers (km) of the coast. Between 1980 and 2002, the population density in coastal communities increased approximately 4.5 times faster than in noncoastal areas of the U.S. (Perkins, 2004). More people generate larger volumes of wastes, increase the demands on wastewater treatment, expand the area of impervious land surfaces, and use more vehicles that contribute contaminants to street runoff. According to the National Coastal Condition Report II (U.S. Environmental Protection Agency, 2005a), on the basis of coastal habitat, water and sediment quality, benthic index, and fish tissue, the overall national coastal condition is only poor to fair and the overall coastal condition in the highly populated Northeast is poor. Scientific information helps managers to prioritize and regulate coastal-ocean uses that include recreation, commercial fishing, transportation, waste disposal, and critical habitat for marine organisms. These uses are often in conflict with each other and with environmental concerns. Developing a strategy for managing competing uses while maintaining sustainability of coastal resources requires scientific understanding of how the coastal ocean system behaves and how it responds to anthropogenic influences. This report provides a summary of a multidisciplinary research program designed to improve our understanding of the transport and fate of contaminants in Massachusetts coastal waters. Massachusetts Bay and Boston Harbor have been a focus of U.S. Geological Survey (USGS) research because they provide a diverse geographic setting for developing a scientific understanding of the geology, geochemistry, and oceanography of

  15. Biological degradation of triclocarban and triclosan in a soil under aerobic and anaerobic conditions and comparison with environmental fate modelling

    Energy Technology Data Exchange (ETDEWEB)

    Ying Guangguo [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); CSIRO Land and Water, Adelaide Laboratory, PMB2, Glen Osmond SA 5064 (Australia)], E-mail: guang-guo.ying@gig.ac.cn; Yu Xiangyang [CSIRO Land and Water, Adelaide Laboratory, PMB2, Glen Osmond SA 5064 (Australia); Food Safety Research Institute, Jiangsu Academy of Agricultural Sciences, Nanjing 210014 (China); Kookana, Rai S. [CSIRO Land and Water, Adelaide Laboratory, PMB2, Glen Osmond SA 5064 (Australia)

    2007-12-15

    Triclocarban and triclosan are two antimicrobial agents widely used in many personal care products. Their biodegradation behaviour in soil was investigated by laboratory degradation experiments and environmental fate modelling. Quantitative structure-activity relationship (QSAR) analyses showed that triclocarban and triclosan had a tendency to partition into soil or sediment in the environment. Fate modelling suggests that either triclocarban or triclosan 'does not degrade fast' with its primary biodegradation half-life of 'weeks' and ultimate biodegradation half-life of 'months'. Laboratory experiments showed that triclocarban and triclosan were degraded in the aerobic soil with half-life of 108 days and 18 days, respectively. No negative effect of these two antimicrobial agents on soil microbial activity was observed in the aerobic soil samples during the experiments. But these two compounds persisted in the anaerobic soil within 70 days of the experimental period. - Triclocarban and triclosan can be degraded by microbial processes in aerobic soil, but will persist in anaerobic soil.

  16. Fate and transport of planar and mono-ortho polychlorinated biphenyls and polychlorinated naphthalenes in Southern California sediments

    OpenAIRE

    Venkatesan, M. Indira

    2003-01-01

    Polychlorinated biphenyls (PCBs) are an important class of industrial pollutants that areubiquitous in the marine and freshwater environments (NAS, 1979). Although the “planar” or“non-ortho” PCB congeners are present in much lower concentrations than other PCBcongeners, they can be responsible for much of the dioxin-like (TCDD) toxicity in the marineecosystem. Further, their environmental fate may be different from other PCBs. Theirdetermination is, therefore, crucial for assessment of contam...

  17. Future trends in transport and fate of diffuse contaminants in catchments, with special emphasis on stable isotope applications

    Science.gov (United States)

    Turner, J.; Albrechtsen, H.-J.; Bonell, M.; Duguet, J.-P.; Harris, B.; Meckenstock, R.; McGuire, K.; Moussa, R.; Peters, N.; Richnow, H.H.; Sherwood-Lollar, B.; Uhlenbrook, S.; van, Lanen H.

    2006-01-01

    A summary is provided of the first of a series of proposed Integrated Science Initiative workshops supported by the UNESCO International Hydrological Programme. The workshop brought together hydrologists, environmental chemists, microbiologists, stable isotope specialists and natural resource managers with the purpose of communicating new ideas on ways to assess microbial degradation processes and reactive transport at catchment scales. The focus was on diffuse contamination at catchment scales and the application of compound-specific isotope analysis (CSIA) in the assessment of biological degradation processes of agrochemicals. Major outcomes were identifying the linkage between water residence time distribution and rates of contaminant degradation, identifying the need for better information on compound specific microbial degradation isotope fractionation factors and the potential of CSIA in identifying key degradative processes. In the natural resource management context, a framework was developed where CSIA techniques were identified as practically unique in their capacity to serve as distributed integrating indicators of process across a range of scales (micro to diffuse) of relevance to the problem of diffuse pollution assessment. Copyright ?? 2006 John Wiley & Sons, Ltd.

  18. Subsurface Uranium Fate and Transport: Integrated Experiments and Modeling of Coupled Biogeochemical Mechanisms of Nanocrystalline Uraninite Oxidation by Fe(III)-(hydr)oxides - Project Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Peyton, Brent M. [Montana State Univ., Bozeman, MT (United States); Timothy, Ginn R. [Univ. of California, Davis, CA (United States); Sani, Rajesh K. [South Dakota School of Mines and Technology, Rapid City, SD (United States)

    2013-08-14

    citrate. To complement to these laboratory studies, we collected U-bearing samples from a surface seep at the Rifle field site and have measured elevated U concentrations in oxic iron-rich sediments. To translate experimental results into numerical analysis of U fate and transport, a reaction network was developed based on Sani et al. (2004) to simulate U(VI) bioreduction with concomitant UO2 reoxidation in the presence of hematite or ferrihydrite. The reduction phase considers SRB reduction (using lactate) with the reductive dissolution of Fe(III) solids, which is set to be microbially mediated as well as abiotically driven by sulfide. Model results show the oxidation of HS– by Fe(III) directly competes with UO2 reoxidation as Fe(III) oxidizes HS– preferentially over UO2. The majority of Fe reduction is predicted to be abiotic, with ferrihydrite becoming fully consumed by reaction with sulfide. Predicted total dissolved carbonate concentrations from the degradation of lactate are elevated (log(pCO2) ~ –1) and, in the hematite system, yield close to two orders-of-magnitude higher U(VI) concentrations than under initial carbonate concentrations of 3 mM. Modeling of U(VI) bioreduction with concomitant reoxidation of UO2 in the presence of ferrihydrite was also extended to a two-dimensional field-scale groundwater flow and biogeochemically reactive transport model for the South Oyster site in eastern Virginia. This model was developed to simulate the field-scale immobilization and subsequent reoxidation of U by a biologically mediated reaction network.

  19. Spatially-distributed influence of agro-environmental factors governing nitrate fate and transport in an irrigated stream-aquifer system

    Science.gov (United States)

    Bailey, R. T.; Ahmadi, M.; Gates, T. K.; Arabi, M.

    2015-02-01

    Elevated levels of nitrate (NO3) in groundwater systems pose a serious risk to human populations and natural ecosystems. As part of an effort to remediate NO3 contamination in irrigated stream-aquifer systems, this study elucidates agricultural and environmental parameters and processes that govern NO3 fate and transport at the regional (500 km2), local (50 km2), and field scales (< 1 km2). Specifically, the revised Morris sensitivity analysis method was applied to a finite-difference nitrogen cycling and reactive transport model of a regional-scale study site in the Lower Arkansas River Valley in southeastern Colorado. The method was used to rank the influence of anthropogenic activities and natural chemical processes on NO3 groundwater concentration, NO3 mass leaching, and NO3 mass loading to the Arkansas River from the aquifer. Sensitivity indices were computed for the entire study area in aggregate as well as each canal command area, crop type, and individual grid cells. Results suggest that fertilizer loading, crop uptake, and heterotrophic denitrification govern NO3 fate and transport for the majority of the study area, while canal NO3 concentration and rates of autotrophic denitrification, nitrification, and humus decomposition dominate or partially dominate in several canal command areas. Also, NO3 leaching and groundwater concentration in adjacent cultivated fields often are governed by different processes and mass inputs/outputs. Results can be used to determine critical processes and key management actions for future data collection and remediation strategies, with efforts able to be focused on localized areas.

  20. Spatially-distributed influence of agro-environmental factors governing nitrate fate and transport in an irrigated stream-aquifer system

    Directory of Open Access Journals (Sweden)

    R. T. Bailey

    2015-02-01

    Full Text Available Elevated levels of nitrate (NO3 in groundwater systems pose a serious risk to human populations and natural ecosystems. As part of an effort to remediate NO3 contamination in irrigated stream-aquifer systems, this study elucidates agricultural and environmental parameters and processes that govern NO3 fate and transport at the regional (500 km2, local (50 km2, and field scales (2. Specifically, the revised Morris sensitivity analysis method was applied to a finite-difference nitrogen cycling and reactive transport model of a regional-scale study site in the Lower Arkansas River Valley in southeastern Colorado. The method was used to rank the influence of anthropogenic activities and natural chemical processes on NO3 groundwater concentration, NO3 mass leaching, and NO3 mass loading to the Arkansas River from the aquifer. Sensitivity indices were computed for the entire study area in aggregate as well as each canal command area, crop type, and individual grid cells. Results suggest that fertilizer loading, crop uptake, and heterotrophic denitrification govern NO3 fate and transport for the majority of the study area, while canal NO3 concentration and rates of autotrophic denitrification, nitrification, and humus decomposition dominate or partially dominate in several canal command areas. Also, NO3 leaching and groundwater concentration in adjacent cultivated fields often are governed by different processes and mass inputs/outputs. Results can be used to determine critical processes and key management actions for future data collection and remediation strategies, with efforts able to be focused on localized areas.

  1. The influence of a non-aqueous phase liquid (NAPL) and chemical oxidant application on perfluoroalkyl acid (PFAA) fate and transport.

    Science.gov (United States)

    McKenzie, Erica R; Siegrist, Robert L; McCray, John E; Higgins, Christopher P

    2016-04-01

    One dimensional column experiments were conducted using saturated porous media containing residual trichloroethylene (TCE) to understand the effects of non-aqueous phase liquids (NAPLs) and chemical oxidation on perfluoroalkyl acid (PFAA) fate and transport. Observed retardation factors and data from supporting batch studies suggested that TCE provides additional sorption capacity that can increase PFAA retardation (i.e., decreased mobility), though the mechanisms remain unclear. Treatment with persulfate activated with FeCl2 and citric acid, catalyzed hydrogen peroxide (CHP), or permanganate did not result in oxidative transformations of PFAAs. However, impacts on PFAA sorption were apparent, and enhanced sorption was substantial in the persulfate-treated columns. In contrast, PFAA transport was accelerated in permanganate- and CHP-treated columns. Ultimately, PFAA transport in NAPL contaminated groundwater is likely influenced by porous media properties, NAPL characteristics, and water quality properties, each of which can change due to chemical oxidant treatment. For contaminated sites for which ISCO is a viable treatment option, changes to PFAA transport and the implications thereof should be included as a component of the remediation evaluation and selection process. PMID:26854608

  2. Processes influencing the transport and fate of contaminated sediments in the coastal ocean: Boston Harbor and Massachusetts Bay

    Science.gov (United States)

    Bothner, Michael H.; Butman, Bradford

    2007-01-01

    Most of the major urban centers of the United States including Boston, New York, Washington, Chicago, New Orleans, Miami, Los Angeles, San Francisco, and Seattle—are on a coast (fig. 1.1). All of these cities discharge treated sewage effluent into adjacent waters. In 2000, 74 percent of the U.S. population lived within 200 kilometers (km) of the coast. Between 1980 and 2002, the population density in coastal communities increased approximately 4.5 times faster than in noncoastal areas of the U.S. (Perkins, 2004). More people generate larger volumes of wastes, increase the demands on wastewater treatment, expand the area of impervious land surfaces, and use more vehicles that contribute contaminants to street runoff. According to the National Coastal Condition Report II (U.S. Environmental Protection Agency, 2005a), on the basis of coastal habitat, water and sediment quality, benthic index, and fish tissue, the overall national coastal condition is only poor to fair and the overall coastal condition in the highly populated Northeast is poor. Scientific information helps managers to prioritize and regulate coastal-ocean uses that include recreation, commercial fishing, transportation, waste disposal, and critical habitat for marine organisms. These uses are often in conflict with each other and with environmental concerns. Developing a strategy for managing competing uses while maintaining sustainability of coastal resources requires scientific understanding of how the coastal ocean system behaves and how it responds to anthropogenic influences. This report provides a summary of a multidisciplinary research program designed to improve our understanding of the transport and fate of contaminants in Massachusetts coastal waters. Massachusetts Bay and Boston Harbor have been a focus of U.S. Geological Survey (USGS) research because they provide a diverse geographic setting for developing a scientific understanding of the geology, geochemistry, and oceanography of

  3. Hydrogeochemical processes governing the origin, transport and fate of major and trace elements from mine wastes and mineralized rock to surface waters

    Science.gov (United States)

    Nordstrom, D. Kirk

    2011-01-01

    The formation of acid mine drainage from metals extraction or natural acid rock drainage and its mixing with surface waters is a complex process that depends on petrology and mineralogy, structural geology, geomorphology, surface-water hydrology, hydrogeology, climatology, microbiology, chemistry, and mining and mineral processing history. The concentrations of metals, metalloids, acidity, alkalinity, Cl-, F- and SO42- found in receiving streams, rivers, and lakes are affected by all of these factors and their interactions. Remediation of mine sites is an engineering concern but to design a remediation plan without understanding the hydrogeochemical processes of contaminant mobilization can lead to ineffective and excessively costly remediation. Furthermore, remediation needs a goal commensurate with natural background conditions rather than water-quality standards that might bear little relation to conditions of a highly mineralized terrain. This paper reviews hydrogeochemical generalizations, primarily from US Geological Survey research, that enhance our understanding of the origin, transport, and fate of contaminants released from mined and mineralized areas.

  4. Pathogens and fecal indicators in waste stabilization pond systems with direct reuse for irrigation: Fate and transport in water, soil and crops.

    Science.gov (United States)

    Verbyla, M E; Iriarte, M M; Mercado Guzmán, A; Coronado, O; Almanza, M; Mihelcic, J R

    2016-05-01

    Wastewater use for irrigation is expanding globally, and information about the fate and transport of pathogens in wastewater systems is needed to complete microbial risk assessments and develop policies to protect public health. The lack of maintenance for wastewater treatment facilities in low-income areas and developing countries results in sludge accumulation and compromised performance over time, creating uncertainty about the contamination of soil and crops. The fate and transport of pathogens and fecal indicators was evaluated in waste stabilization ponds with direct reuse for irrigation, using two systems in Bolivia as case studies. Results were compared with models from the literature that have been recommended for design. The removal of Escherichia coli in both systems was adequately predicted by a previously-published dispersed flow model, despite more than 10years of sludge accumulation. However, a design equation for helminth egg removal overestimated the observed removal, suggesting that this equation may not be appropriate for systems with accumulated sludge. To assess the contamination of soil and crops, ratios were calculated of the pathogen and fecal indicator concentrations in soil or on crops to their respective concentrations in irrigation water (termed soil-water and crop-water ratios). Ratios were similar within each group of microorganisms but differed between microorganism groups, and were generally below 0.1mLg(-1) for coliphage, between 1 and 100mLg(-1) for Giardia and Cryptosporidium, and between 100 and 1000mLg(-1) for helminth eggs. This information can be used for microbial risk assessments to develop safe water reuse policies in support of the United Nations' 2030 Sustainable Development Agenda. PMID:26881733

  5. Development of a multimedia model (POPsLTEA) to assess the influence of climate change on the fate and transport of polycyclic aromatic hydrocarbons in East Asia.

    Science.gov (United States)

    Song, Jee Hey; Lee, Yunah; Lee, Dong Soo

    2016-11-01

    A dynamic multimedia model (POPsLTEA) for an East Asia region was developed and evaluated to quantitatively assess how climate change (CC) alters the environmental fate and transport dynamics of 16 polycyclic aromatic hydrocarbons (PAHs) in air, water, soil, and sediment. To cover the entire model domain (25°N-50°N and 98°E-148°E) where China, Japan, and South and North Koreas are of primary concern, a total of 5000 main cells of 50km×50km size were used while 1008 cells of a finer spatial resolution (12.5km×12.5km) was nested for South Korea (33°N-38°N and 126°E-132°E). Most of the predicted concentrations agreed with the observed values within one order of magnitude with a tendency of overestimation for air and sediment. Prediction of the atmospheric concentration was statistically significant in both coincidence and association, suggesting the model's potential to successfully predict the fate and transport of the PAHs as influenced by CC. An example study of benzo(a)pyrene demonstrates that direction and strength of the CC influence on the pollution levels vary with the location and environmental media. As compared to the five year period of 2011 to 2015, the changes across the model domain in the annual geometric mean concentration over the years of 2021 through 2100 were predicted to range from 88% to 304%, from 84% to 109%, from 32% to 362%, and from 49% to 303%, in air, soil, surface water, and sea water, respectively, under the scenario of RCP8.5. PMID:27380393

  6. Development of a multimedia model (POPsLTEA) to assess the influence of climate change on the fate and transport of polycyclic aromatic hydrocarbons in East Asia.

    Science.gov (United States)

    Song, Jee Hey; Lee, Yunah; Lee, Dong Soo

    2016-11-01

    A dynamic multimedia model (POPsLTEA) for an East Asia region was developed and evaluated to quantitatively assess how climate change (CC) alters the environmental fate and transport dynamics of 16 polycyclic aromatic hydrocarbons (PAHs) in air, water, soil, and sediment. To cover the entire model domain (25°N-50°N and 98°E-148°E) where China, Japan, and South and North Koreas are of primary concern, a total of 5000 main cells of 50km×50km size were used while 1008 cells of a finer spatial resolution (12.5km×12.5km) was nested for South Korea (33°N-38°N and 126°E-132°E). Most of the predicted concentrations agreed with the observed values within one order of magnitude with a tendency of overestimation for air and sediment. Prediction of the atmospheric concentration was statistically significant in both coincidence and association, suggesting the model's potential to successfully predict the fate and transport of the PAHs as influenced by CC. An example study of benzo(a)pyrene demonstrates that direction and strength of the CC influence on the pollution levels vary with the location and environmental media. As compared to the five year period of 2011 to 2015, the changes across the model domain in the annual geometric mean concentration over the years of 2021 through 2100 were predicted to range from 88% to 304%, from 84% to 109%, from 32% to 362%, and from 49% to 303%, in air, soil, surface water, and sea water, respectively, under the scenario of RCP8.5.

  7. Pathogens and fecal indicators in waste stabilization pond systems with direct reuse for irrigation: Fate and transport in water, soil and crops.

    Science.gov (United States)

    Verbyla, M E; Iriarte, M M; Mercado Guzmán, A; Coronado, O; Almanza, M; Mihelcic, J R

    2016-05-01

    Wastewater use for irrigation is expanding globally, and information about the fate and transport of pathogens in wastewater systems is needed to complete microbial risk assessments and develop policies to protect public health. The lack of maintenance for wastewater treatment facilities in low-income areas and developing countries results in sludge accumulation and compromised performance over time, creating uncertainty about the contamination of soil and crops. The fate and transport of pathogens and fecal indicators was evaluated in waste stabilization ponds with direct reuse for irrigation, using two systems in Bolivia as case studies. Results were compared with models from the literature that have been recommended for design. The removal of Escherichia coli in both systems was adequately predicted by a previously-published dispersed flow model, despite more than 10years of sludge accumulation. However, a design equation for helminth egg removal overestimated the observed removal, suggesting that this equation may not be appropriate for systems with accumulated sludge. To assess the contamination of soil and crops, ratios were calculated of the pathogen and fecal indicator concentrations in soil or on crops to their respective concentrations in irrigation water (termed soil-water and crop-water ratios). Ratios were similar within each group of microorganisms but differed between microorganism groups, and were generally below 0.1mLg(-1) for coliphage, between 1 and 100mLg(-1) for Giardia and Cryptosporidium, and between 100 and 1000mLg(-1) for helminth eggs. This information can be used for microbial risk assessments to develop safe water reuse policies in support of the United Nations' 2030 Sustainable Development Agenda.

  8. A 3D hydrodynamic fate and transport model for herbicides in Sacca di Goro coastal lagoon (Northern Adriatic).

    Science.gov (United States)

    Carafa, R; Marinov, D; Dueri, S; Wollgast, J; Ligthart, J; Canuti, E; Viaroli, P; Zaldívar, J M

    2006-10-01

    Sacca di Goro is a shallow coastal microtidal lagoon with a surface area of 26 km2, and an average depth of about 1.5m. Fresh water pollutant loads from Po River branches and several drainage canals lead to anthropogenic eutrophication, frequent summer anoxia crises and chemical contamination. Such events not only affect the lagoon ecosystem but also cause serious economic losses, the lagoon being the second largest producer of clams in Italy. The present work aims at using a fate model coupled with COHERENS 3D hydrodynamic model to simulate and to explain the spatial distribution and temporal variations of s-triazines herbicides in the Sacca di Goro lagoon. The simulation results of spatial and temporal dynamic behaviour of atrazine, simazine and terbuthylazine have been compared with experimental data obtained during an annual monitoring programme. PMID:16643962

  9. Molecular motor traffic: From biological nanomachines to macroscopic transport

    Science.gov (United States)

    Lipowsky, Reinhard; Chai, Yan; Klumpp, Stefan; Liepelt, Steffen; Müller, Melanie J. I.

    2006-12-01

    All cells of animals and plants contain complex transport systems based on molecular motors which walk along cytoskeletal filaments. These motors are rather small and have a size of 20-100 nm but are able to pull vesicles, organelles and other types of cargo over large distances, from micrometers up to meters. There are several families of motors: kinesins, dyneins, and myosins. Most of these motors have two heads which are used as legs and perform discrete steps along the filaments. Several aspects of the motor behavior will be discussed: motor cycles of two-headed motors; walks of single motors or cargo particles which consist of directed movements interrupted by random, diffusive motion; cargo transport through tube-like compartments; active diffusion of cargo particles in slab-like compartments; cooperative transport of cargo by several motors which may be uni- or bi-directional; and systems with many interacting motors that exhibit traffic jams, self-organized density and flux patterns, and traffic phase transitions far from equilibrium. It is necessary to understand these traffic phenomena in a quantitative manner in order to construct and optimize biomimetic transport systems based on motors and filaments with many possible applications in bioengineering, pharmacology, and medicine.

  10. Factors affecting the fate and transport of glyphosate and AMPA into surface waters of agricultural watersheds in the United States and Europe

    Science.gov (United States)

    Coupe, R.; Kalkhoff, S.; Capel, P.; Gregoire, C.

    2012-04-01

    Glyphosate [N-(phosphonomethyl)glycine] is a herbicide used extensively in almost all agricultural and urban areas of the United States and Europe. Although, glyphosate is used widely throughout the world in the production of many crops, it is predominately used in the United States on soybeans, corn, potatoes, and cotton that have been genetically modified to be tolerant to glyphosate. From 1992 to 2007, the agricultural use of glyphosate has increased from less than 10,000 Mg to more than 80,000 Mg, respectively. The greatest areal use is in the midwestern United States where glyphosate is applied on transgenic corn and soybeans. Because of the difficulty and expense in analyzing for glyphosate and AMPA (aminomethylphosphonic acid, a primary glyphosate degradate) in water, there have been only small scale studies on the fate and transport of glyphosate. The characterization of the transport of glyphosate and AMPA on a watershed scale is lacking. Glyphosate and AMPA were frequently detected in the surface waters of 4 agricultural watersheds in studies conducted by the U.S. Geological Survey in the United States and at the Laboratory of Hydrology and Geochemistry of Strasbourg. Two of these basins were located in the midwestern United States where the major crops are corn and soybean, the third is located the lower Mississippi River Basin where the major crops are soybean, corn, rice, and cotton, and the fourth was located near Strasbourg, France where the use of glyphosate was on a vineyard. The load as a percent of use ranged from 0.009 to 0.86 percent and could be related to 3 factors: source strength, hydrology, and flowpath. Glyphosate use in a watershed results in some occurrence in surface water at the part per billion level; however, those watersheds most at risk for the offsite transport of glyphosate are those with high application rates, rainfall that results in overland runoff, and a flowpath that does not include transport through the soil.

  11. Variations in the fate and biological effects of sulfamethoxazole, norfloxacin and doxycycline in different vegetable-soil systems following manure application.

    Science.gov (United States)

    Wang, Jianmei; Lin, Hui; Sun, Wanchun; Xia, Yun; Ma, Junwei; Fu, Jianrong; Zhang, Zulin; Wu, Huizhen; Qian, Mingrong

    2016-03-01

    The fate of sulfamethoxazole (SMZ), norfloxacin (NOR) and doxycycline (DOX) and their biological effects in radish and pakchoi culture systems were investigated. DOX dissipated more rapidly than SMZ and NOR, while radish and pakchoi cultivation increased the removal of residual DOX in soils. Dissipation of NOR was accelerated in radish soils but was slowed down slightly in pakchoi soils. Vegetable cultivation exerted an insignificant effect on SMZ removal. Investigation of antibiotic bioaccumulation showed that the uptake of DOX by radish and pakchoi was undetectable, but the radish accumulated more SMZ and NOR than pakchoi. Among the three antibiotics, only SMZ use exhibited an apparent suspension of plant seed germination, up-ground plant growth and soil microbial diversity. Pakchoi responded more sensitively to SMZ than did the radish. Principal component analysis (PCA) based on MicroRESP™ indicated that the sampling time and antibiotic treatments could influence the soil microbial community. Only in the pakchoi soils did antibiotic application exert a more robust effect on the microbial community than the sampling time; SMZ treatments and DOX treatments could be clearly discriminated from the control treatments. These results are crucial for an assessment of the potential risks of antibiotics to culture system practices and suggest that good agricultural practices help to limit or even reduce antibiotic pollution. PMID:26546703

  12. Linking carbon and iron cycles by investigating transport, fate and mineralogy of iron-bearing colloids from peat-draining rivers - Scotland as model for high-latitude rivers

    Science.gov (United States)

    Wood, Deborah; Crocket, Kirsty; Brand, Tim; Stutter, Marc; Wilson, Clare; Schröder, Christian

    2016-04-01

    Linking carbon and iron cycles by investigating transport, fate and mineralogy of iron-bearing colloids from peat-draining rivers - Scotland as model for high-latitude rivers Wood, D.A¹, Crocket, K², Brand, T², Stutter, M³, Wilson, C¹ & Schröder, C¹ ¹Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA ²Scottish Association for Marine Science, University of the Highlands and Islands, Dunbeg, Oban, PA37 1QA ³James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH The biogeochemical iron cycle exerts significant control on the carbon cycle¹. Iron is a limiting nutrient in large areas of the world's oceans and its bioavailability controls CO2 uptake by marine photosynthesizing microorganisms. While atmospheric iron inputs to the open ocean have been extensively measured, global river inputs have likely been underestimated because most major world rivers exhibit extensive iron removal by flocculation and sedimentation during seawater mixing. Iron minerals and organic matter mutually stabilise each other², which results in a 'rusty carbon sink' in sediments³ on the one hand but may also enhance transport beyond the salinity gradient on the other. Humic-rich, high latitude rivers have a higher iron-carrying capacity⁴-⁶ but are underrepresented in iron flux calculations. The West Coast sea lochs in Scotland are fed by predominantly peatland drainage catchments, and the rivers entering the sea lochs carry a high load of organic matter. The short distance between many of these catchments and the coastal ocean facilitates source-to-sea research investigating transport, fate and mineralogy of iron-bearing colloids providing a good analogue for similar high latitude fjordic systems. We use SeaFAST+ICP-MS and Mössbauer spectroscopy to survey trace metal concentrations, with emphasis on iron concentrations, speciation and mineralogy, across salinity gradients. In combination with ultra-filtration techniques, this allows

  13. Development, calibration, and predictive results of a simulator for subsurface pathway fate and transport of aqueous- and gaseous-phase contaminants in the Subsurface Disposal Area at the Idaho National Engineering and Environmental Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Magnuson, S.O.; Sondrup, A.J.

    1998-07-01

    This document presents the development, calibration, and predictive results of a simulation study of fate and transport of waste buried in the Subsurface Disposal Area (SDA) (which is hereafter referred to as the SDA simulation study). This report builds on incorporates a previous report that dealt only with the calibration of a flow model for simulation of water movement beneath the SDA (Magnuson and Sondrup 1996). The primary purpose of the SDA simulation study was to perform fate and transport calculations to support the IRA. A secondary purpose of the SDA simulation study was to be able to use the model to evaluate possible remediation strategies and their effects on flow and transport in the OU 7-13/14 feasibility study.

  14. Divalent metal transporter 1 regulates iron-mediated ROS and pancreatic ß cell fate in response to cytokines

    DEFF Research Database (Denmark)

    Hansen, Jakob Bondo; Tonnesen, Morten Fog; Madsen, Andreas Nygaard;

    2012-01-01

    Reactive oxygen species (ROS) contribute to target-cell damage in inflammatory and iron-overload diseases. Little is known about iron transport regulation during inflammatory attack. Through a combination of in vitro and in vivo studies, we show that the proinflammatory cytokine IL-1ß induces...... divalent metal transporter 1 (DMT1) expression correlating with increased ß cell iron content and ROS production. Iron chelation and siRNA and genetic knockdown of DMT1 expression reduce cytokine-induced ROS formation and cell death. Glucose-stimulated insulin secretion in the absence of cytokines in Dmt1...

  15. Water transport mechanism through open capillaries analyzed by direct surface modifications on biological surfaces

    Science.gov (United States)

    Ishii, Daisuke; Horiguchi, Hiroko; Hirai, Yuji; Yabu, Hiroshi; Matsuo, Yasutaka; Ijiro, Kuniharu; Tsujii, Kaoru; Shimozawa, Tateo; Hariyama, Takahiko; Shimomura, Masatsugu

    2013-10-01

    Some small animals only use water transport mechanisms passively driven by surface energies. However, little is known about passive water transport mechanisms because it is difficult to measure the wettability of microstructures in small areas and determine the chemistry of biological surfaces. Herein, we developed to directly analyse the structural effects of wettability of chemically modified biological surfaces by using a nanoliter volume water droplet and a hi-speed video system. The wharf roach Ligia exotica transports water only by using open capillaries in its legs containing hair- and paddle-like microstructures. The structural effects of legs chemically modified with a self-assembled monolayer were analysed, so that the wharf roach has a smart water transport system passively driven by differences of wettability between the microstructures. We anticipate that this passive water transport mechanism may inspire novel biomimetic fluid manipulations with or without a gravitational field.

  16. Ion transport through biological membranes an integrated theoretical approach

    CERN Document Server

    Mackey, Michael C

    1975-01-01

    This book illustrates some of the ways physics and mathematics have been, and are being, used to elucidate the underlying mechan­ isms of passive ion movement through biological membranes in general, and the membranes of excltable cells in particular. I have made no effort to be comprehensive in my introduction of biological material and the reader interested in a brief account of single cell electro­ physlology from a physically-oriented biologists viewpoint will find the chapters by Woodbury (1965) an excellent introduction. Part I is introductory in nature, exploring the basic electrical properties of inexcitable and excitable cell plasma membranes. Cable theory is utilized to illustrate the function of the non-decrementing action potential as a signaling mechanism for the long range trans­ mission of information in the nervous system, and to gain some in­ sight into the gross behaviour of neurons. The detailed analysis of Hodgkin and Huxley on the squid giant axon membrane ionic conductance properties...

  17. CranSLIK v1.0: stochastic prediction of oil spill transport and fate using approximation methods

    OpenAIRE

    Snow, B J; I. Moulitsas; Kolios, A. J.; De Dominicis, M.

    2014-01-01

    This paper investigates the development of a model, called CranSLIK, to predict the transport and transformations of a point mass oil spill via a stochastic approach. Initially the various effects on destination are considered and key parameters are chosen which are expected to dominate the displacement. The variables considered are: wind velocity, surface water velocity, spill size, and spill age. For a point mass oil spill, it is found that the centre of m...

  18. Characterization of crushed tuff for the evaluation of the fate of tracers in transport studies in the unsaturated zone

    International Nuclear Information System (INIS)

    Results of field-scale (caisson) transport studies under unsaturated moisture and steady and nonsteady flow conditions indicate variability and a lack of conservation of mass in solute transport. The tuff materials used in that study were analyzed for the presence of tracers and of freshly precipitated material to help explain the variability and lack of conservation of mass. Selected tuff samples were characterized by neutron activation analysis for tracer identification, by x-ray diffraction for mineral identification, by petrographic analysis for identification of freshly precipitated material, and by x-ray fluorescence analysis for identification of major and trace elements. The results of these analyses indicate no obvious presence of freshly precipitated material that would retard tracer movement. The presence of the nonsorbing tracers (bromide and iodide) suggest the retention of these tracers in immobile water. The presence of the nonsorbing tracers (bromide and iodide) suggest the retention of these tracers in immobile water. The presence of sorbing and nonsorbing tracers on the tuff at some locations (even cesium at the 415-cm depth) and not at others suggests variability in transport. 15 refs., 14 figs., 9 tabs

  19. Transport, fate, and stimulating impact of silver nanoparticles on the removal of Cd(II) by Phanerochaete chrysosporium in aqueous solutions

    International Nuclear Information System (INIS)

    Highlights: • Appropriate concentration of AgNPs can stimulate the biological removal of Cd(II). • Added AgNPs were oxidatively dissolved and transported to the surface of fungus. • AgNPs have undergone coarsening in the process of transport. • Amino, carboxyl, hydroxyl, and other reducing groups were involved in transportion. - Abstract: Despite the knowledge about increasing discharge of silver nanoparticles (AgNPs) into wastewater and its potential toxicity to microorganisms, the interaction of AgNPs with heavy metals in the biological removal process remains poorly understood. This study focused on the effect of AgNPs (hydrodynamic diameter about 24.3 ± 0.37 nm) on the removal of cadmium (Cd(II)) by using a model white rot fungus species, Phanerochaete chrysosporium. Results showed that the biological removal capacity of Cd(II) increased with the concentration of AgNPs increasing from 0.1 mg/L to 1 mg/L. The maximum removal capacity (4.67 mg/g) was located at 1 mg/L AgNPs, and then decreased with further increasing AgNPs concentration, suggesting that an appropriate concentration of AgNPs has a stimulating effect on the removal of Cd(II) by P. chrysosporium instead of an inhibitory effect. Results of Ag+ and total Ag concentrations in the solutions together with those of SEM and XRD demonstrated that added AgNPs had undergone oxidative dissolution and transported from the solution to the surface of fungal mycelia (up to 94%). FTIR spectra confirmed that amino, carboxyl, hydroxyl, and other reducing functional groups were involved in Cd(II) removal, AgNPs transportation, and the reduction of Ag+ to AgNPs

  20. Transport, fate, and stimulating impact of silver nanoparticles on the removal of Cd(II) by Phanerochaete chrysosporium in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Yanan [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Chen, Guiqiu, E-mail: gqchen@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Zeng, Guangming, E-mail: zgming@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Li, Zhongwu; Yan, Ming [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Chen, Anwei [College of Resources and Environment, Hunan Agricultural University, Changsha 410128 (China); Guo, Zhi; Huang, Zhenzhen; Tan, Qiong [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China)

    2015-03-21

    Highlights: • Appropriate concentration of AgNPs can stimulate the biological removal of Cd(II). • Added AgNPs were oxidatively dissolved and transported to the surface of fungus. • AgNPs have undergone coarsening in the process of transport. • Amino, carboxyl, hydroxyl, and other reducing groups were involved in transportion. - Abstract: Despite the knowledge about increasing discharge of silver nanoparticles (AgNPs) into wastewater and its potential toxicity to microorganisms, the interaction of AgNPs with heavy metals in the biological removal process remains poorly understood. This study focused on the effect of AgNPs (hydrodynamic diameter about 24.3 ± 0.37 nm) on the removal of cadmium (Cd(II)) by using a model white rot fungus species, Phanerochaete chrysosporium. Results showed that the biological removal capacity of Cd(II) increased with the concentration of AgNPs increasing from 0.1 mg/L to 1 mg/L. The maximum removal capacity (4.67 mg/g) was located at 1 mg/L AgNPs, and then decreased with further increasing AgNPs concentration, suggesting that an appropriate concentration of AgNPs has a stimulating effect on the removal of Cd(II) by P. chrysosporium instead of an inhibitory effect. Results of Ag{sup +} and total Ag concentrations in the solutions together with those of SEM and XRD demonstrated that added AgNPs had undergone oxidative dissolution and transported from the solution to the surface of fungal mycelia (up to 94%). FTIR spectra confirmed that amino, carboxyl, hydroxyl, and other reducing functional groups were involved in Cd(II) removal, AgNPs transportation, and the reduction of Ag{sup +} to AgNPs.

  1. Development and application of a catchment scale pesticide fate and transport model for use in drinking water risk assessment.

    Science.gov (United States)

    Pullan, S P; Whelan, M J; Rettino, J; Filby, K; Eyre, S; Holman, I P

    2016-09-01

    This paper describes the development and application of IMPT (Integrated Model for Pesticide Transport), a parameter-efficient tool for predicting diffuse-source pesticide concentrations in surface waters used for drinking water supply. The model was applied to a small UK headwater catchment with high frequency (8h) pesticide monitoring data and to five larger catchments (479-1653km(2)) with sampling approximately every 14days. Model performance was good for predictions of both flow (Nash Sutcliffe Efficiency generally >0.59 and PBIAS operational and strategic risk assessments. PMID:27151500

  2. Transport and fate of ammonium and its impact on uranium and other trace elements at a former uranium mill tailing site

    International Nuclear Information System (INIS)

    Highlights: • Nitrification of ammonium evidenced by stable isotopes of nitrate at a mining site. • Concentrations of uranium and other trace elements related to ammonium conc. • Observed impact of ammonium on redox, pH, and possibly complexation. • Proposed impact of transformation of NO3 and NH4 on trace elements. - Abstract: The remediation of ammonium-containing groundwater discharged from uranium mill tailing sites is a difficult problem facing the mining industry. The Monument Valley site is a former uranium mining site in the southwest US with both ammonium and nitrate contamination of groundwater. In this study, samples collected from 14 selected wells were analyzed for major cations and anions, trace elements, and isotopic composition of ammonium and nitrate. In addition, geochemical data from the U.S. Department of Energy (DOE) database were analyzed. Results showing oxic redox conditions and correspondence of isotopic compositions of ammonium and nitrate confirmed the natural attenuation of ammonium via nitrification. Moreover, it was observed that ammonium concentration within the plume area is closely related to concentrations of uranium and a series of other trace elements including chromium, selenium, vanadium, iron, and manganese. It is hypothesized that ammonium–nitrate transformation processes influence the disposition of the trace elements through mediation of redox potential, pH, and possibly aqueous complexation and solid-phase sorption. Despite the generally relatively low concentrations of trace elements present in groundwater, their transport and fate may be influenced by remediation of ammonium or nitrate at the site

  3. Molecular cell biology and physiology of solute transport

    Science.gov (United States)

    Caplan, Michael J.; Seo-Mayer, Patricia; Zhang, Li

    2010-01-01

    Purpose of review An enormous body of research has been focused on exploring the mechanisms through which epithelial cells establish their characteristic polarity. It is clear that under normal circumstances cell–cell contacts mediated by the calcium-dependent adhesion proteins of the intercellular adhesion junctions are required to initiate complete polarization. Furthermore, formation of the tight, or occluding, junctions that limit paracellular permeability has long been thought to help to establish polarity by preventing the diffusion of membrane proteins between the two plasmalemmal domains. This review will discuss several selected kinases and protein complexes and highlight their relevance to transporting epithelial cell polarization. Recent findings Recent work has shed new light on the roles of junctional complexes in establishing and maintaining epithelial cell polarity. In addition, work from several laboratories, suggests that the formation of these junctions is tied to processes that regulate cellular energy metabolism. Summary Junctional complexes and energy sensing kinases constitute a novel class of machinery whose capacity to generate and modulate epithelial cell polarity is likely to have wide ranging and important physiological ramifications. PMID:18695392

  4. Innovation in biological production and upgrading of methane and hydrogen for use as gaseous transport biofuel.

    Science.gov (United States)

    Xia, Ao; Cheng, Jun; Murphy, Jerry D

    2016-01-01

    Biofuels derived from biomass will play a major role in future renewable energy supplies in transport. Gaseous biofuels have superior energy balances, offer greater greenhouse gas emission reductions and produce lower pollutant emissions than liquid biofuels. Biogas derived through fermentation of wet organic substrates will play a major role in future transport systems. Biogas (which is composed of approximately 60% methane/hydrogen and 40% carbon dioxide) requires an upgrading process to reduce the carbon dioxide content to less than 3% before it is used as compressed gas in transport. This paper reviews recent developments in fermentative biogas production and upgrading as a transport fuel. Third generation gaseous biofuels may be generated using marine-based algae via two-stage fermentation, cogenerating hydrogen and methane. Alternative biological upgrading techniques, such as biological methanation and microalgal biogas upgrading, have the potential to simultaneously upgrade biogas, increase gaseous biofuel yield and reduce carbon dioxide emission. PMID:26724182

  5. Mobility of Source Zone Heavy Metals and Radionuclides: The Mixed Roles of Fermentative Activity on Fate and Transport of U and Cr. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Gerlach, Robin [Montana State Univ., Bozeman, MT (United States); Peyton, Brent M. [Montana State Univ., Bozeman, MT (United States); Apel, William A. [Idaho National Lab., Idaho Falls, ID (United States)

    2014-01-29

    Various U. S. Department of Energy (DOE) low and medium-level radioactive waste sites contain mixtures of heavy metals, radionuclides and assorted organic materials. In addition, there are numerous sites around the world that are contaminated with a mixture of organic and inorganic contaminants. In most sites, over time, water infiltrates the wastes, and releases metals, radionuclides and other contaminants causing transport into the surrounding environment. We investigated the role of fermentative microorganisms in such sites that may control metal, radionuclide and organics migration from source zones. The project was initiated based on the following overarching hypothesis: Metals, radionuclides and other contaminants can be mobilized by infiltration of water into waste storage sites. Microbial communities of lignocellulose degrading and fermenting microorganisms present in the subsurface of contaminated DOE sites can significantly impact migration by directly reducing and immobilizing metals and radionuclides while degrading complex organic matter to low molecular weight organic compounds. These low molecular weight organic acids and alcohols can increase metal and radionuclide mobility by chelation (i.e., certain organic acids) or decrease mobility by stimulating respiratory metal reducing microorganisms. We demonstrated that fermentative organisms capable of affecting the fate of Cr6+, U6+ and trinitrotoluene can be isolated from organic-rich low level waste sites as well as from less organic rich subsurface environments. The mechanisms, pathways and extent of contaminant transformation depend on a variety of factors related to the type of organisms present, the aqueous chemistry as well as the geochemistry and mineralogy. This work provides observations and quantitative data across multiple scales that identify and predict the coupled effects of fermentative carbon and electron flow on the transport of radionuclides, heavy metals and organic contaminants in

  6. Thermo-fluidic devices and materials inspired from mass and energy transport phenomena in biological system

    Institute of Scientific and Technical Information of China (English)

    Jian XIAO; Jing LIU

    2009-01-01

    Mass and energy transport consists of one of the most significant physiological processes in nature, which guarantees many amazing biological phenomena and activ-ities. Borrowing such idea, many state-of-the-art thermo-fluidic devices and materials such as artificial kidneys, carrier erythrocyte, blood substitutes and so on have been successfully invented. Besides, new emerging technologies are still being developed. This paper is dedicated to present-ing a relatively complete review of the typical devices and materials in clinical use inspired by biological mass and energy transport mechanisms. Particularly, these artificial thermo-fluidic devices and materials will be categorized into organ transplantation, drug delivery, nutrient transport, micro operation, and power supply. Potential approaches for innovating conventional technologies were discussed, corresponding biological phenomena and physical mechan-isms were interpreted, future promising mass-and-energy-transport-based bionic devices were suggested, and prospects along this direction were pointed out. It is expected that many artificial devices based on biological mass and energy transport principle will appear to better improve vari-ous fields related to human life in the near future.

  7. Research plan: geochemical, hydrological and biological cycling of energy residuals. Subsurface Transport Program

    International Nuclear Information System (INIS)

    Energy development and production, particularly the generation of various waste products, have resulted in a need for long term scientific information on the geochemical transformations, transport rates, and potential for bioaccumulation or biotransformation of contaminants in subsurface environments. This plan describes proposed research goals and specific research directions intended to address these scientific questions. Research needs are grouped into three areas: (1) biogeo-chemical mobilization; (2) hydrological transport in subsurface systems; and (3) biological uptake and food chain transfer

  8. Geochemical, hydrological and biological cycling of energy residuals. Research plan: Subsurface Transport Program. Revision

    International Nuclear Information System (INIS)

    Energy development and production, particularly the generation of various waste products, have resulted in a need for long-term scientific information on the geochemical transformations, transport rates, and potential for bioaccumulation or biotransformation of contaminants in subsurface environments. This plan describes proposed research goals and specific research directions intended to address these scientific questions. Research needs are grouped into three areas: (1) biogeochemical mobilization; (2) hydrological transport in subsurface systems; and (3) biological uptake and food chain transfer

  9. A new multimedia contaminant fate model for China: how important are environmental parameters in influencing chemical persistence and long-range transport potential?

    Science.gov (United States)

    Zhu, Ying; Price, Oliver R; Tao, Shu; Jones, Kevin C; Sweetman, Andy J

    2014-08-01

    We present a new multimedia chemical fate model (SESAMe) which was developed to assess chemical fate and behaviour across China. We apply the model to quantify the influence of environmental parameters on chemical overall persistence (POV) and long-range transport potential (LRTP) in China, which has extreme diversity in environmental conditions. Sobol sensitivity analysis was used to identify the relative importance of input parameters. Physicochemical properties were identified as more influential than environmental parameters on model output. Interactive effects of environmental parameters on POV and LRTP occur mainly in combination with chemical properties. Hypothetical chemicals and emission data were used to model POV and LRTP for neutral and acidic chemicals with different KOW/DOW, vapour pressure and pKa under different precipitation, wind speed, temperature and soil organic carbon contents (fOC). Generally for POV, precipitation was more influential than the other environmental parameters, whilst temperature and wind speed did not contribute significantly to POV variation; for LRTP, wind speed was more influential than the other environmental parameters, whilst the effects of other environmental parameters relied on specific chemical properties. fOC had a slight effect on POV and LRTP, and higher fOC always increased POV and decreased LRTP. Example case studies were performed on real test chemicals using SESAMe to explore the spatial variability of model output and how environmental properties affect POV and LRTP. Dibenzofuran released to multiple media had higher POV in northwest of Xinjiang, part of Gansu, northeast of Inner Mongolia, Heilongjiang and Jilin. Benzo[a]pyrene released to the air had higher LRTP in south Xinjiang and west Inner Mongolia, whilst acenaphthene had higher LRTP in Tibet and west Inner Mongolia. TCS released into water had higher LRTP in Yellow River and Yangtze River catchments. The initial case studies demonstrated that SESAMe

  10. Final Report Coupling in silico microbial models with reactive transport models to predict the fate of contaminants in the subsurface.

    Energy Technology Data Exchange (ETDEWEB)

    Lovley, Derek R.

    2012-10-31

    This project successfully accomplished its goal of coupling genome-scale metabolic models with hydrological and geochemical models to predict the activity of subsurface microorganisms during uranium bioremediation. Furthermore, it was demonstrated how this modeling approach can be used to develop new strategies to optimize bioremediation. The approach of coupling genome-scale metabolic models with reactive transport modeling is now well enough established that it has been adopted by other DOE investigators studying uranium bioremediation. Furthermore, the basic principles developed during our studies will be applicable to much broader investigations of microbial activities, not only for other types of bioremediation, but microbial metabolism in diversity of environments. This approach has the potential to make an important contribution to predicting the impact of environmental perturbations on the cycling of carbon and other biogeochemical cycles.

  11. Treatment of large bone defects with a novel biological transport disc in non-vascular transport distraction osteogenesis.

    Science.gov (United States)

    Zeng, J J; Guo, P; Zhou, N; Xie, Q T; Liao, F C

    2016-05-01

    The aim of this study was to investigate a potential novel biological transport disc that avoids secondary injury to the body and facilitates bone healing. Twenty-seven dogs were divided randomly into three groups: group A were treated with human bone morphogenetic protein 2 (BMP-2) modified bone mesenchymal stem cell (BMSC) sheets combined with freeze-dried bone allograft as biological transport disc; group B were treated with BMSC sheets combined with freeze-dried bone allograft as transport disc (control); and group C were treated with direct extension only (blank). There were nine dogs in each group. Non-vascular transport distraction osteogenesis was performed in groups A and B to repair the mandibular bone defects, and in group C only mandibular truncation surgery was performed. The regeneration of bone was evaluated through X-ray, haematoxylin and eosin assay, and immunohistochemistry. After 2, 4, and 8 weeks of distraction, new bone density values in group A were 49.00±1.16, 66.63±2.62, and 72.78±2.67, respectively, and these were significantly different to values in groups B (P=0.0005, P=0.0004, P=0.0012) and C (Pdistraction osteogenesis.

  12. Estimation of light transport parameters in biological media using coherent backscattering

    Indian Academy of Sciences (India)

    S Anantha Ramakrishna; K Divakara Rao

    2000-02-01

    The suitability of using the angular peak shape of the coherent backscattered light for estimating the light transport parameters of biological media has been investigated. Milk and methylene blue doped milk were used as tissue phantoms for the measurements carried out with a He–Ne laser (632.8 nm). Results indicate that while the technique accurately estimates the transport length, it can determine the absorption coefficient only when the absorption is moderately high ( > 1 cm-1) for the long transport lengths typical of tissues. Further, the possibility of determining the anisotropy factor by estimating the single scattering contribution to the diffuse background is examined.

  13. CranSLIK v1.0: stochastic prediction of oil spill transport and fate using approximation methods

    Science.gov (United States)

    Snow, B. J.; Moulitsas, I.; Kolios, A. J.; De Dominicis, M.

    2014-07-01

    This paper investigates the development of a model, called CranSLIK, to predict the transport and transformations of a point mass oil spill via a stochastic approach. Initially the various effects on destination are considered and key parameters are chosen which are expected to dominate the displacement. The variables considered are: wind velocity, surface water velocity, spill size, and spill age. For a point mass oil spill, it is found that the centre of mass can be determined by the wind and current data only, and the spill size and age can then be used to reconstruct the surface of the spill. These variables are sampled and simulations are performed using an open-source Lagrangian approach-based code, MEDSLIK II. Regression modelling is applied to create two sets of polynomials: one for the centre of mass, and one for the spill size. Simulations performed for a real oil spill case show that a minimum of approximately 80% of the oil is captured by CranSLIK. Finally, Monte Carlo simulation is implemented to allow for consideration of the most likely destination for the oil spill, when the distributions for the oceanographic conditions are known.

  14. CranSLIK v1.0: stochastic prediction of oil spill transport and fate using approximation methods

    Directory of Open Access Journals (Sweden)

    B. J. Snow

    2014-07-01

    Full Text Available This paper investigates the development of a model, called CranSLIK, to predict the transport and transformations of a point mass oil spill via a stochastic approach. Initially the various effects on destination are considered and key parameters are chosen which are expected to dominate the displacement. The variables considered are: wind velocity, surface water velocity, spill size, and spill age. For a point mass oil spill, it is found that the centre of mass can be determined by the wind and current data only, and the spill size and age can then be used to reconstruct the surface of the spill. These variables are sampled and simulations are performed using an open-source Lagrangian approach-based code, MEDSLIK II. Regression modelling is applied to create two sets of polynomials: one for the centre of mass, and one for the spill size. Simulations performed for a real oil spill case show that a minimum of approximately 80% of the oil is captured by CranSLIK. Finally, Monte Carlo simulation is implemented to allow for consideration of the most likely destination for the oil spill, when the distributions for the oceanographic conditions are known.

  15. INEEL Subregional Conceptual Model Report Volume 2: Summary of Existing Knowledge of Geochemical Influences on the Fate and Transport of Contaminants in the Subsurface at the INEEL

    Energy Technology Data Exchange (ETDEWEB)

    Paul L. Wichlacz; Robert C. Starr; Brennon Orr

    2003-09-01

    . The documents that appeared to be the most pertinent were selected from further review. These documents are tabulated in the citation list. This report summarizes existing geochemical conceptual models, but does not attempt to generate a new conceptual model or select the ''right'' model. This document is organized as follows. Geochemical models are described in general in Section 2. Geochemical processes that control the transport and fate of contaminants introduced into groundwater are described in Section 3. The natural geochemistry of the Eastern Snake River Plain Aquifer (SRPA) is described in Section 4. The effect of waste disposal on the INEEL subsurface is described in Section 5. The geochemical behavior of the major contaminants is described in Section 6. Section 7 describes the site-specific geochemical models developed for various INEEL facilities.

  16. Evaluation of the fate and transport of chlorinated ethenes in a complex groundwater system discharging to a stream in Wonju, Korea

    Science.gov (United States)

    Lee, Seong-Sun; Kaown, Dugin; Lee, Kang-Kun

    2015-11-01

    Chlorinated ethenes such as trichloroethylene (TCE) are common and persistent groundwater contaminants. If contaminated groundwater discharges to a stream, then stream water pollution near the contamination site also becomes a problem. In this respect, the fate and transport of chlorinated ethenes around a stream in an industrial complex were evaluated using the concentration of each component, and hydrogeochemical, microbial, and compound-specific carbon isotope data. Temporal and spatial monitoring reveal that a TCE plume originating from main and local source zones continues to be discharged to a stream. Groundwater geochemical data indicate that aerobic conditions prevail in the upgradient area of the studied aquifer, whereas conditions become anaerobic in the downgradient. The TCE molar fraction is high at the main and local source zones, ranging from 87.4 to 99.2% of the total volatile organic compounds (VOCs). An increasing trend in the molar fraction of cis-1, 2-Dichloroethene (cis-DCE) and vinyl chloride (VC) was observed in the downgradient zone of the study area. The enriched δ13C values of TCE and depleted values of cis-DCE in the stream zone, compared to those of the source zone, also suggest biodegradation of VOCs. Microbial community structures in monitoring wells adjacent to the stream zone in the downgradient area were analyzed using 16S rRNA gene-based pyrosequencing to identify the microorganisms responsible for biodegradation. This was attributed to the high relative abundance of dechlorinating bacteria in monitoring wells under anaerobic conditions farthest from the stream in the downgradient area. The multilateral approaches adopted in this study, combining hydrogeochemical and biomolecular methods with compound-specific analyses, indicate that contaminants around the stream were naturally attenuated by active anaerobic biotransformation processes.

  17. REDUCING UNCERTAINTIES IN MODEL PREDICTIONS VIA HISTORY MATCHING OF CO2 MIGRATION AND REACTIVE TRANSPORT MODELING OF CO2 FATE AT THE SLEIPNER PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Chen

    2015-03-31

    An important question for the Carbon Capture, Storage, and Utility program is “can we adequately predict the CO2 plume migration?” For tracking CO2 plume development, the Sleipner project in the Norwegian North Sea provides more time-lapse seismic monitoring data than any other sites, but significant uncertainties still exist for some of the reservoir parameters. In Part I, we assessed model uncertainties by applying two multi-phase compositional simulators to the Sleipner Benchmark model for the uppermost layer (Layer 9) of the Utsira Sand and calibrated our model against the time-lapsed seismic monitoring data for the site from 1999 to 2010. Approximate match with the observed plume was achieved by introducing lateral permeability anisotropy, adding CH4 into the CO2 stream, and adjusting the reservoir temperatures. Model-predicted gas saturation, CO2 accumulation thickness, and CO2 solubility in brine—none were used as calibration metrics—were all comparable with the interpretations of the seismic data in the literature. In Part II & III, we evaluated the uncertainties of predicted long-term CO2 fate up to 10,000 years, due to uncertain reaction kinetics. Under four scenarios of the kinetic rate laws, the temporal and spatial evolution of CO2 partitioning into the four trapping mechanisms (hydrodynamic/structural, solubility, residual/capillary, and mineral) was simulated with ToughReact, taking into account the CO2-brine-rock reactions and the multi-phase reactive flow and mass transport. Modeling results show that different rate laws for mineral dissolution and precipitation reactions resulted in different predicted amounts of trapped CO2 by carbonate minerals, with scenarios of the conventional linear rate law for feldspar dissolution having twice as much mineral trapping (21% of the injected CO2) as scenarios with a Burch-type or Alekseyev et al.–type rate law for feldspar dissolution (11%). So far, most reactive transport modeling (RTM) studies for

  18. Geochemical evidence of groundwater flow paths and the fate and transport of constituents of concern in the alluvial aquifer at Fort Wingate Depot Activity, New Mexico, 2009

    Science.gov (United States)

    Robertson, Andrew J.; Henry, David W.; Langman, Jeffery B.

    2013-01-01

    As part of an environmental investigation at Fort Wingate Depot Activity, New Mexico, the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, interpreted aqueous geochemical concentrations to better understand the groundwater flow paths and the fate and transport of constituents of concern in the alluvial aquifer underlying the study area. The fine-grained nature of the alluvial matrix creates a highly heterogeneous environment, which adds to the difficulty of characterizing the flow of groundwater and the fate of aqueous constituents of concern. The analysis of the groundwater geochemical data collected in October 2009 provides evidence that is used to identify four groundwater flow paths and their extent in the aquifer and indicates the dominant attenuation processes for the constituents of concern. The extent and interaction of groundwater flow paths were delineated by the major ion concentrations and their relations to each other. Four areas of groundwater recharge to the study area were identified based on groundwater elevations, hydrogeologic characteristics, and geochemical and isotopic evidence. One source of recharge enters the study area from the saturated alluvial deposits underlying the South Fork of the Puerco River to the north of the study area. A second source of recharge is shown to originate from a leaky cistern containing production water from the San Andres-Glorieta aquifer. The other two sources of recharge are shown to enter the study area from the south: one from an arroyo valley draining an area to the south and one from hill-front recharge that passes under the reported release of perchlorate and explosive constituents. The spatial extent and interaction of groundwater originating from these various sources along identified flow paths affect the persistence and attenuation of constituents of concern. It was determined that groundwater originating in the area of a former explosives’ wash-out operation and an

  19. Bioinformatics for transporter pharmacogenomics and systems biology: data integration and modeling with UML.

    Science.gov (United States)

    Yan, Qing

    2010-01-01

    Bioinformatics is the rational study at an abstract level that can influence the way we understand biomedical facts and the way we apply the biomedical knowledge. Bioinformatics is facing challenges in helping with finding the relationships between genetic structures and functions, analyzing genotype-phenotype associations, and understanding gene-environment interactions at the systems level. One of the most important issues in bioinformatics is data integration. The data integration methods introduced here can be used to organize and integrate both public and in-house data. With the volume of data and the high complexity, computational decision support is essential for integrative transporter studies in pharmacogenomics, nutrigenomics, epigenetics, and systems biology. For the development of such a decision support system, object-oriented (OO) models can be constructed using the Unified Modeling Language (UML). A methodology is developed to build biomedical models at different system levels and construct corresponding UML diagrams, including use case diagrams, class diagrams, and sequence diagrams. By OO modeling using UML, the problems of transporter pharmacogenomics and systems biology can be approached from different angles with a more complete view, which may greatly enhance the efforts in effective drug discovery and development. Bioinformatics resources of membrane transporters and general bioinformatics databases and tools that are frequently used in transporter studies are also collected here. An informatics decision support system based on the models presented here is available at http://www.pharmtao.com/transporter . The methodology developed here can also be used for other biomedical fields.

  20. Electronic and Transport Properties of Quasi-1D Wires of Biological Molecules

    Science.gov (United States)

    Oetzel, Björn; Matthes, Lars; Tandetzky, Falk; Ortmann, Frank; Bechstedt, Friedhelm; Hannewald, Karsten

    2010-03-01

    In the search for organic materials with good charge-transport properties, artificial stacks of biological molecules are considered attractive candidates [1,2]. In this spirit, we present ab-initio DFT calculations of the structural, electronic, and quantum-transport properties of quasi-1D wires based on guanine and eumelanin molecules [3]. Hereby, a special focus is put on the results for the electronic bandwidths and the consequences for potential applications. [4pt] [1] R. di Felice et al., Phys. Rev. B 65, 045104 (2001) [0pt] [2] P. Meredith et al., Pigment Cell Res. 19, 572 (2006) [0pt] [3] B. Oetzel et al. (unpublished)

  1. Nonequilibrium thermodynamics transport and rate processes in physical, chemical and biological systems

    CERN Document Server

    Demirel, Yasar

    2014-01-01

    Natural phenomena consist of simultaneously occurring transport processes and chemical reactions. These processes may interact with each other and may lead to self-organized structures, fluctuations, instabilities, and evolutionary systems. Nonequilibrium Thermodynamics, 3rd edition emphasizes the unifying role of thermodynamics in analyzing the natural phenomena. This third edition updates and expands on the first and second editions by focusing on the general balance equations for coupled processes of physical, chemical, and biological systems. The new edition contains a new chapte

  2. Fate and transport of cyanobacteria and associated toxins and taste-and-odor compounds from upstream reservoir releases in the Kansas River, Kansas, September and October 2011

    Science.gov (United States)

    Graham, Jennifer L.; Ziegler, Andrew C.; Loving, Brian L.; Loftin, Keith A.

    2012-01-01

    Cyanobacteria cause a multitude of water-quality concerns, including the potential to produce toxins and taste-and-odor compounds. Toxins and taste-and-odor compounds may cause substantial economic and public health concerns and are of particular interest in lakes, reservoirs, and rivers that are used for drinking-water supply, recreation, or aquaculture. The Kansas River is a primary source of drinking water for about 800,000 people in northeastern Kansas. Water released from Milford Lake to the Kansas River during a toxic cyanobacterial bloom in late August 2011 prompted concerns about cyanobacteria and associated toxins and taste-and-odor compounds in downstream drinking-water supplies. During September and October 2011 water-quality samples were collected to characterize the transport of cyanobacteria and associated compounds from upstream reservoirs to the Kansas River. This study is one of the first to quantitatively document the transport of cyanobacteria and associated compounds during reservoir releases and improves understanding of the fate and transport of cyanotoxins and taste-and-odor compounds downstream from reservoirs. Milford Lake was the only reservoir in the study area with an ongoing cyanobacterial bloom during reservoir releases. Concentrations of cyanobacteria and associated toxins and taste-and-odor compounds in Milford Lake (upstream from the dam) were not necessarily indicative of outflow conditions (below the dam). Total microcystin concentrations, one of the most commonly occurring cyanobacterial toxins, in Milford Lake were 650 to 7,500 times higher than the Kansas Department of Health and Environment guidance level for a public health warning (20 micrograms per liter) for most of September 2011. By comparison, total microcystin concentrations in the Milford Lake outflow generally were less than 10 percent of the concentrations in surface accumulations, and never exceeded 20 micrograms per liter. The Republican River, downstream from

  3. Stochastic and deterministic multiscale models for systems biology: an auxin-transport case study

    Directory of Open Access Journals (Sweden)

    King John R

    2010-03-01

    Full Text Available Abstract Background Stochastic and asymptotic methods are powerful tools in developing multiscale systems biology models; however, little has been done in this context to compare the efficacy of these methods. The majority of current systems biology modelling research, including that of auxin transport, uses numerical simulations to study the behaviour of large systems of deterministic ordinary differential equations, with little consideration of alternative modelling frameworks. Results In this case study, we solve an auxin-transport model using analytical methods, deterministic numerical simulations and stochastic numerical simulations. Although the three approaches in general predict the same behaviour, the approaches provide different information that we use to gain distinct insights into the modelled biological system. We show in particular that the analytical approach readily provides straightforward mathematical expressions for the concentrations and transport speeds, while the stochastic simulations naturally provide information on the variability of the system. Conclusions Our study provides a constructive comparison which highlights the advantages and disadvantages of each of the considered modelling approaches. This will prove helpful to researchers when weighing up which modelling approach to select. In addition, the paper goes some way to bridging the gap between these approaches, which in the future we hope will lead to integrative hybrid models.

  4. A transport and fate model of C-14 in a bay of the Baltic Sea at SFR. Today and in future

    International Nuclear Information System (INIS)

    The environmental transport and fate of a hypothetical release of radioactive carbon-14 from SFR-1 (the final repository for radioactive operational waste) was investigated using an ecosystem modelling approach. The approach involved identification, quantification and dynamic modelling of the main flows and storages of carbon both in the physical environment and in the food web. Carbon-14 was in the model introduced into the food web via photosynthesising organisms. Contamination of the aquatic ecosystem above SFR-1 was then assessed assuming a release of 5.13 x 107 Bq/year for 1,000 years. Modelling results were used to estimate steady-state C-14 concentrations in biota, exposure (Gy) of biota and dose (Sv) to humans consuming contaminated organisms both if the discharge occurred today (2000 AD)and if it occurred in the future (4000 AD). Since the modelled area is characterised by a fast water exchange, most of the discharged C-14 was flushed out of the system more or less immediately (99.8% and 98.4% at 2000 AD and 4000 AD, respectively). However, a small fraction of the discharge was assimilated by primary producers (0.18% and 2.11%), which enabled subsequent transfer of C-14 to organisms at higher trophic levels (e.g. fish, seals and humans). The exported C-14 from the area was diluted to very low concentrations in the large recipient outside. Estimated exposures were very low, and differed significantly among the studied biota (17.2 x 10-12 to 2.3 x 10-6 Gy). In general the highest exposures were observed in benthic plants and benthic grazers followed by fish and benthos. Humans consuming large quantities of locally produced food (e.g.fish, mussels and algae) will receive an exposure in case of C-14 contamination. Estimated doses to humans were approximately 10-100 nSv per year, which is significantly lower than restrictions by the authorities. The developed model was also used to evaluate implications of various assumptions concerning the route of C-14 entry

  5. A transport and fate model of C-14 in a bay of the Baltic Sea at SFR. Today and in future

    Energy Technology Data Exchange (ETDEWEB)

    Kumblad, L. [Stockholm Univ. (Sweden). Dept. of Systems Ecology

    2001-06-01

    The environmental transport and fate of a hypothetical release of radioactive carbon-14 from SFR-1 (the final repository for radioactive operational waste) was investigated using an ecosystem modelling approach. The approach involved identification, quantification and dynamic modelling of the main flows and storages of carbon both in the physical environment and in the food web. Carbon-14 was in the model introduced into the food web via photosynthesising organisms. Contamination of the aquatic ecosystem above SFR-1 was then assessed assuming a release of 5.13 x 10{sup 7} Bq/year for 1,000 years. Modelling results were used to estimate steady-state C-14 concentrations in biota, exposure (Gy) of biota and dose (Sv) to humans consuming contaminated organisms both if the discharge occurred today (2000 AD)and if it occurred in the future (4000 AD). Since the modelled area is characterised by a fast water exchange, most of the discharged C-14 was flushed out of the system more or less immediately (99.8% and 98.4% at 2000 AD and 4000 AD, respectively). However, a small fraction of the discharge was assimilated by primary producers (0.18% and 2.11%), which enabled subsequent transfer of C-14 to organisms at higher trophic levels (e.g. fish, seals and humans). The exported C-14 from the area was diluted to very low concentrations in the large recipient outside. Estimated exposures were very low, and differed significantly among the studied biota (17.2 x 10{sup -12} to 2.3 x 10{sup -6} Gy). In general the highest exposures were observed in benthic plants and benthic grazers followed by fish and benthos. Humans consuming large quantities of locally produced food (e.g.fish, mussels and algae) will receive an exposure in case of C-14 contamination. Estimated doses to humans were approximately 10-100 nSv per year, which is significantly lower than restrictions by the authorities. The developed model was also used to evaluate implications of various assumptions concerning the

  6. Factors Effecting the Fate and Transport of CL-20 in the Vadose Zone and Groundwater: Final Report 2002 - 2004 SERDP Project CP-1255

    Energy Technology Data Exchange (ETDEWEB)

    Szecsody, James E.; Riley, Robert G.; Devary, Brooks J.; Girvin, Donald C.; Resch, Charles T.; Campbell, James A.; Fredrickson, Herbert L.; Thompson, Karen T.; Crocker, Fiona H.; Qasim, Mohammad M.; Gamerdinger, Amy P.; Lemond, Luke A.

    2005-06-01

    This SERDP-funded project was initiated to investigate the fate of CL-20 in the subsurface environment, with a focus on identification and quantification of geochemical and microbial reactions of CL-20. CL-20 can be released to the surface and subsurface terrestrial environment by: a) manufacturing processes, b) munition storage, and c) use with low order detonation or unexploded ordnance. The risk of far-field subsurface migration was assessed through labora-tory experiments with a variety of sediments and subsurface materials to quantify processes that control CL-20 sorption-limited migration and degradation. Results of this study show that CL-20 will exhibit differing behavior in the subsurface terrestrial environment: 1. CL-20 on the sediment surface will photodegrade and interact with plants/animals (described in other SERDP projects CU 1254, 1256). CL-20 will exhibit greater sorption in humid sediments to organic matter. Transport will be solubility limited (i.e., low CL-20 aqueous solubility). 2. CL-20 infiltration into soils (<2 m) from spills will be subject to sorption to soil organic matter (if present), and low to high biodegradation rates (weeks to years) depending on the microbial population (greater in humid environment). 3. CL-20 in the vadose zone (>2 m) will be, in most cases, subject to low sorption and low degradation rates, so would persist in the subsurface environment and be at risk for deep migration. Low water content in arid regions will result in a decrease in both sorption and the degradation rate. Measured degradation rates in unsaturated sediments of years would result in significant subsurface migration distances. 4. CL-20 in groundwater will be subject to some sorption but likely very slow degradation rates. CL-20 sorption will be greater than RDX. Most CL-20 degradation will be abiotic (ferrous iron and other transition metals), because most deep subsurface systems have extremely low natural microbial populations. Degradation rates

  7. Virus fate and transport during recharge using recycled water at a research field site in the Montebello Forebay, Los Angeles County, California, 1997-2000

    Science.gov (United States)

    Anders, Robert; Yanko, William A.; Schroeder, Roy A.; Jackson, James L.

    2004-01-01

    Total and fecal coliform bacteria distributions in subsurface water samples collected at a research field site in Los Angeles County were found to increase from nondetectable levels immediately before artificial recharge using tertiary-treated municipal wastewater (recycled water). This rapid increase indicates that bacteria can move through the soil with the percolating recycled water over intervals of a few days and vertical and horizontal distances of about 3 meters. This conclusion formed the basis for three field-scale experiments using bacterial viruses (bacteriophage) MS2 and PRD1 as surrogates for human enteric viruses and bromide as a conservative tracer to determine the fate and transport of viruses in recycled water during subsurface transport under actual recharge conditions. The research field site consists of a test basin constructed adjacent to a large recharge facility (spreading grounds) located in the Montebello Forebay of Los Angeles County, California. The soil beneath the test basin is predominantly medium to coarse, moderately sorted, grayish-brown sand. The three tracer experiments were conducted during August 1997, August-September 1998, and August 2000. For each experiment, prepared solutions of bacteriophage and bromide were sprayed on the surface of the water in the test basin and injected, using peristaltic pumps, directly into the feed pipe delivering the recycled water to the test basin. Extensive data were obtained for water samples collected from the test basin itself and from depths of 0.3, 0.6, 1.0, 1.5, 3.0, and 7.6 meters below the bottom of the test basin. The rate of bacteriophage inactivation in the recycled water, independent of any processes occurring in the subsurface, was determined from measurements on water samples from the test basin. Regression analysis of the ratios of bacteriophage to bromide was used to determine the attenuation rates for MS2 and PRD1, defined as the logarithmic reduction in the ratio during each

  8. Fate of Environmental Pollutants.

    Science.gov (United States)

    Padhye, Lokesh P

    2016-10-01

    This annual review covers the literature published in 2015 on topics related to the occurrence and fate of emerging environmental pollutants in wastewater. Due to the vast amount of literature published on this topic, I have discussed only a fraction of the quality research publications, up to maximum 20 relevant articles per section, due to limitation of space. The abstract search was carried out using Web of Science, and the abstracts were selected based on their relevance. In few cases, full-text articles were referred to better understand new findings. This review is divided into the following sections: biological agents, disinfection by-products (DBPs), halogenated compounds, pharmaceuticals and personal care products (PPCPs), and other emerging contaminants. PMID:27620105

  9. Fate and transport of cyanobacteria and associated toxins and taste-and-odor compounds from upstream reservoir releases in the Kansas River, Kansas, September and October 2011

    Science.gov (United States)

    Graham, Jennifer L.; Ziegler, Andrew C.; Loving, Brian L.; Loftin, Keith A.

    2012-01-01

    Cyanobacteria cause a multitude of water-quality concerns, including the potential to produce toxins and taste-and-odor compounds. Toxins and taste-and-odor compounds may cause substantial economic and public health concerns and are of particular interest in lakes, reservoirs, and rivers that are used for drinking-water supply, recreation, or aquaculture. The Kansas River is a primary source of drinking water for about 800,000 people in northeastern Kansas. Water released from Milford Lake to the Kansas River during a toxic cyanobacterial bloom in late August 2011 prompted concerns about cyanobacteria and associated toxins and taste-and-odor compounds in downstream drinking-water supplies. During September and October 2011 water-quality samples were collected to characterize the transport of cyanobacteria and associated compounds from upstream reservoirs to the Kansas River. This study is one of the first to quantitatively document the transport of cyanobacteria and associated compounds during reservoir releases and improves understanding of the fate and transport of cyanotoxins and taste-and-odor compounds downstream from reservoirs. Milford Lake was the only reservoir in the study area with an ongoing cyanobacterial bloom during reservoir releases. Concentrations of cyanobacteria and associated toxins and taste-and-odor compounds in Milford Lake (upstream from the dam) were not necessarily indicative of outflow conditions (below the dam). Total microcystin concentrations, one of the most commonly occurring cyanobacterial toxins, in Milford Lake were 650 to 7,500 times higher than the Kansas Department of Health and Environment guidance level for a public health warning (20 micrograms per liter) for most of September 2011. By comparison, total microcystin concentrations in the Milford Lake outflow generally were less than 10 percent of the concentrations in surface accumulations, and never exceeded 20 micrograms per liter. The Republican River, downstream from

  10. Experimental terrestrial soil-core microcosm test protocol. A method for measuring the potential ecological effects, fate, and transport of chemicals in terrestrial ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Van Voris, P.; Tolle, D.A.; Arthur, M.F.

    1985-06-01

    In order to protect the environment properly and have a realistic appraisal of how a chemical will act in the environment, tests of ecological effects and chemical fate must be performed on complex assemblages of biotic and abiotic components (i.e., microcosms) as well as single species. This protocol is one which could be added to a series of tests recently developed as guidelines for Section 4 of the Toxic Substances Control Act (P.L. 94-469; U.S.C., Section 2601-2629). The terrestrial soil-core microcosm is designed to supply site-specific and possibly regional information on the probable chemical fate and ecological effects resulting from release of a chemical substance to a terrestrial ecosystem. The EPA will use the data resulting from this test system to compare the potential hazards of a chemical with others that have been previously evaluated.

  11. Fate and transport of petroleum hydrocarbons in soil and ground water at Big South Fork National River and Recreation Area, Tennessee and Kentucky, 2002-2003

    Science.gov (United States)

    Williams, Shannon D.; Ladd, David E.; Farmer, James

    2006-01-01

    In 2002 and 2003, the U.S. Geological Survey (USGS), by agreement with the National Park Service (NPS), investigated the effects of oil and gas production operations on ground-water quality at Big South Fork National River and Recreation Area (BISO) with particular emphasis on the fate and transport of petroleum hydrocarbons in soils and ground water. During a reconnaissance of ground-water-quality conditions, samples were collected from 24 different locations (17 springs, 5 water-supply wells, 1 small stream, and 1 spring-fed pond) in and near BISO. Benzene, toluene, ethylbenzene, and xylene (BTEX) compounds were not detected in any of the water samples, indicating that no widespread contamination of ground-water resources by dissolved petroleum hydrocarbons probably exists at BISO. Additional water-quality samples were collected from three springs and two wells for more detailed analyses to obtain additional information on ambient water-quality conditions at BISO. Soil gas, soil, water, and crude oil samples were collected at three study sites in or near BISO where crude oil had been spilled or released (before 1993). Diesel range organics (DRO) were detected in soil samples from all three of the sites at concentrations greater than 2,000 milligrams per kilogram. Low concentrations (less than 10 micrograms per kilogram) of BTEX compounds were detected in lab-analyzed soil samples from two of the sites. Hydrocarbon-degrading bacteria counts in soil samples from the most contaminated areas of the sites were not greater than counts for soil samples from uncontaminated (background) sites. The elevated DRO concentrations, the presence of BTEX compounds, and the low number of -hydrocarbon-degrading bacteria in contaminated soils indicate that biodegradation of petroleum hydrocarbons in soils at these sites is incomplete. Water samples collected from the three study sites were analyzed for BTEX and DRO. Ground-water samples were collected from three small springs at the

  12. Suitability of Commercial Transport Media for Biological Pathogens under Nonideal Conditions

    Directory of Open Access Journals (Sweden)

    Kyle Hubbard

    2011-01-01

    Full Text Available There is extensive data to support the use of commercial transport media as a stabilizer for known clinical samples; however, there is little information to support their use outside of controlled conditions specified by the manufacturer. Furthermore, there is no data to determine the suitability of said media for biological pathogens, specifically those of interest to the US military. This study evaluates commercial off-the-shelf (COTS transport media based on sample recovery, viability, and quality of nucleic acids and peptides for nonpathogenic strains of Bacillus anthracis, Yersinia pestis, and Venezuelan equine encephalitis virus, in addition to ricin toxin. Samples were stored in COTS, PBST, or no media at various temperatures over an extended test period. The results demonstrate that COTS media, although sufficient for the preservation of nucleic acid and proteinaceous material, are not capable of maintaining an accurate representation of biothreat agents at the time of collection.

  13. Reactive transport in aquatic ecosystems: Rapid model prototyping in the open source software R

    NARCIS (Netherlands)

    Soetaert, K.; Meysman, F.

    2012-01-01

    The concentrations of many natural compounds are altered by chemical and biological transformations, and physical processes such as adsorption and transport. Their fate can be predicted using reactive transport models that describe reaction and advective and dispersive movement of these components i

  14. Constructing Soliton and Kink Solutions of PDE Models in Transport and Biology

    Directory of Open Access Journals (Sweden)

    Vsevolod A. Vladimirov

    2006-06-01

    Full Text Available We present a review of our recent works directed towards discovery of a periodic, kink-like and soliton-like travelling wave solutions within the models of transport phenomena and the mathematical biology. Analytical description of these wave patterns is carried out by means of our modification of the direct algebraic balance method. In the case when the analytical description fails, we propose to approximate invariant travelling wave solutions by means of an infinite series of exponential functions. The effectiveness of the method of approximation is demonstrated on a hyperbolic modification of Burgers equation.

  15. Multi-functionalized single-walled carbon nanotubes as tumor cell targeting biological transporters

    International Nuclear Information System (INIS)

    Multi-functionalized single walled carbon nanotubes (SWNTs) were prepared and applied as tumor cell targeting biological transporters. A positive charge was introduced on SWNTs to get high loading efficiency of fluorescein (FAM) labeled short double strands DNA (20 base pairs). The SWNTs were encapsulated with the folic acid modified phospholipids for active targeting into tumor cell. The tumor cell-targeting properties of these multi-functionalized SWNTs were investigated by active targeting into mouse ovarian surface epithelial cells. The experimental results show that these multi-functionalized SWNTs have good tumor cell targeting property

  16. Proton transport in biological systems can be probed by two-dimensional infrared spectroscopy

    Science.gov (United States)

    Liang, Chungwen; Jansen, Thomas L. C.; Knoester, Jasper

    2011-01-01

    We propose a new method to determine the proton transfer (PT) rate in channel proteins by two-dimensional infrared (2DIR) spectroscopy. Proton transport processes in biological systems, such as proton channels, trigger numerous fundamental biochemical reactions. Due to the limitation in both spatial and time resolution of the traditional experimental approaches, describing the whole proton transport process and identifying the rate limiting steps at the molecular level is challenging. In the present paper, we focus on proton transport through the Gramicidin A channel. Using a kinetic PT model derived from all-atom molecular dynamics simulations, we model the amide I region of the 2DIR spectrum of the channel protein to examine its sensitivity to the proton transport process. We demonstrate that the 2DIR spectrum of the isotope-labeled channel contain information on the PT rate, which may be extracted by analyzing the antidiagonal linewidth of the spectral feature related to the labeled site. Such experiments in combination with detailed numerical simulations should allow the extraction of site dependent PT rates, providing a method for identifying possible rate limiting steps for proton channel transfer.

  17. Characterization of the Hanford 300 area burial grounds. Task IV. Biological transport

    International Nuclear Information System (INIS)

    The characteristics of radioactive waste burial sites at the 300 area burial grounds on the Department of Energy's Hanford Site, southeastern Washington were studied. The potential vectors of radionuclide transport studied were vegetation and animals. The overall results showed a low potential for uptake and transport of radionuclides from the 300 area sites. However, additional methods to control physical and biological mechanisms may contribute to the effectiveness of waste burial practices. From the results, the Biological Transport task recommended field studies which include reduction of soil erosion and addition of biobarriers to plants and animals. Vegetation plays a major role in reducing soil erosion, and thereby maintaining the backfill over the burial sites. Of the several species found on the 300 area sites, cheatgrass (Bromus tectorum) appears to be the most desirable as a cover. Besides retarding erosion, it has a shallow root system (does not easily penetrate buried material); it has a low affinity for radionuclide uptake; and its tissues are not easily blown away. Small mammals (specifically, mice) appear to have the most potential for radionuclide exposure and uptake. Small mammals were live-trapped within 10 x 10-meter trap grids. Each animal trapped was surgically implanted with a thermoluminescent dosimeter. When the animal was recaptured, the dosimeter was removed and read for exposure. Exposures were reported in milli-Roentgens. The most consistently trapped small mammals were the Great Basin pocket mouse (Perognathus parvus) and the deer mouse (Peromyscus maniculatus). Results from the dosimeter readings showed that some of those animals had higher than background exposures. Biobarriers to animals could be considered as a mechanism to reduce the potential for radionuclide transport

  18. Characterization of the Hanford 300 area burial grounds. Task IV. Biological transport

    Energy Technology Data Exchange (ETDEWEB)

    Fitzner, R.E.; Gano, K.A.; Rickard, W.H.; Rogers, L.E.

    1979-10-01

    The characteristics of radioactive waste burial sites at the 300 area burial grounds on the Department of Energy's Hanford Site, southeastern Washington were studied. The potential vectors of radionuclide transport studied were vegetation and animals. The overall results showed a low potential for uptake and transport of radionuclides from the 300 area sites. However, additional methods to control physical and biological mechanisms may contribute to the effectiveness of waste burial practices. From the results, the Biological Transport task recommended field studies which include reduction of soil erosion and addition of biobarriers to plants and animals. Vegetation plays a major role in reducing soil erosion, and thereby maintaining the backfill over the burial sites. Of the several species found on the 300 area sites, cheatgrass (Bromus tectorum) appears to be the most desirable as a cover. Besides retarding erosion, it has a shallow root system (does not easily penetrate buried material); it has a low affinity for radionuclide uptake; and its tissues are not easily blown away. Small mammals (specifically, mice) appear to have the most potential for radionuclide exposure and uptake. Small mammals were live-trapped within 10 x 10-meter trap grids. Each animal trapped was surgically implanted with a thermoluminescent dosimeter. When the animal was recaptured, the dosimeter was removed and read for exposure. Exposures were reported in milli-Roentgens. The most consistently trapped small mammals were the Great Basin pocket mouse (Perognathus parvus) and the deer mouse (Peromyscus maniculatus). Results from the dosimeter readings showed that some of those animals had higher than background exposures. Biobarriers to animals could be considered as a mechanism to reduce the potential for radionuclide transport.

  19. Characterization and simulation of fate and transport of selected volatile organic compounds in the vicinities of the Hadnot Point Industrial Area and landfill: Chapter A Supplement 6 in Analyses and historical reconstruction of groundwater flow, contaminant fate and transport, and distribution of drinking water within the service areas of the Hadnot Point and Holcomb Boulevard Water Treatment Plants and vicinities, U.S. Marine Corps Base Camp Lejeune, North Carolina

    Science.gov (United States)

    Jones, L. Elliott; Suárez-Soto, René J.; Anderson, Barbara A.; Maslia, Morris L.

    2013-01-01

    This supplement of Chapter A (Supplement 6) describes the reconstruction (i.e. simulation) of historical concentrations of tetrachloroethylene (PCE), trichloroethylene (TCE), and benzene3 in production wells supplying water to the Hadnot Base (USMCB) Camp Lejeune, North Carolina (Figure S6.1). A fate and transport model (i.e., MT3DMS [Zheng and Wang 1999]) was used to simulate contaminant migration from source locations through the groundwater system and to estimate mean contaminant concentrations in water withdrawn from water-supply wells in the vicinity of the Hadnot Point Industrial Area (HPIA) and the Hadnot Point landfill (HPLF) area.4 The reconstructed contaminant concentrations were subsequently input into a flow-weighted, materials mass balance (mixing) model (Masters 1998) to estimate monthly mean concentrations of the contaminant in finished water 5 at the HPWTP (Maslia et al. 2013). The calibrated fate and transport models described herein were based on and used groundwater velocities derived from groundwater-flow models that are described in Suárez-Soto et al. (2013). Information data pertinent to historical operations of water-supply wells are described in Sautner et al. (2013) and Telci et al. (2013).

  20. Biological transport of persistent organic pollutants (POPs) to Lake Ellasjoeen, Bjoernoeya (Bear Island), Norway

    Energy Technology Data Exchange (ETDEWEB)

    Evenset, A.; Christensen, G. [Akvaplan-niva, Tromso (Norway); Kallenborn, R. [Norwegian Inst. for Air Research, Kjeller (Norway); Herzke, D. [Norwegian Inst. for Air Research, Tromso (Norway)

    2004-09-15

    During recent years, multidisciplinary studies have been carried out on Bjoernoeya (Bear Island, Norway), elucidating the fate and the presence of persistent organic pollutants (POPs) in this pristine Arctic environment. High concentrations of POPs, like polychlorinated biphenyls (PCBs), dichloro-diphenyl-dichlorethane (DDE) and polybrominated diphenyl ethers (PBDEs) have been measured in sediment and biota from Ellasjoeen, a lake located in the southern, mountainous part of Bjoernoeya. In Lake Oeyangen, located only 6 km north of Ellasjoeen on the central plains of the island, levels of POPs are several times lower than in Ellasjoeen. One reason for the different POP contamination levels in Ellasjoeen and Oeyangen is probably differences in precipitation regime between the southern mountainous part of the island and the central plains further north, leading to differences in the deposition of air transported contaminants. Another possible source for contaminants to Ellasjoeen is the large colonies of seabirds (mainly kittiwake (Rissa tridactyla), little auk (Alle alle) and glaucous gull (Larus hyperboreus)), which are situated close to the lake during the ice-free period (early June - October). These seabirds feed in the marine environment, and deposit large amounts of guano (excrements) directly into the lake or in the catchment area of the lake. Oeyangen is not influenced by seabirds. There are two ways in which input from seabirds can lead to higher levels of POPs in Ellasjoeen: direct input of POPs through allochthonous material (guano, bird remains) a change in trophic state of the lake as a result of nutrient loadings from the seabirds. The aim of the present study was to investigate the role of guano as a transport medium for POPs to Ellasjoeen. Two main approaches were followed: an investigation of the trophic status of Ellasjoeen, as well as the reference lake, Oeyangen, through analyses of stable isotopes of carbon and nitrogen, analyses of selected

  1. Hydrodynamics and convection enhanced macromolecular fluid transport in soft biological tissues: Application to solid tumor.

    Science.gov (United States)

    Dey, Bibaswan; Sekhar, G P Raja

    2016-04-21

    This work addresses a theoretical framework for transvascular exchange and extravascular transport of solute macromolecules through soft interstitial space inside a solid tumor. Most of the soft biological tissues show materialistic properties similar to deformable porous material. They exhibit mechanical behavior towards the fluid motion since the solid phase of the tumor tissue gets compressed by the drag force that is associated with the extracellular fluid flow. This paper presents a general view about the transvascular and interstitial transport of solute nutrients inside a tumor in the macroscopic level. Modified Starling׳s equation is used to describe transvascular nutrient transport. On the macroscopic level, motion of extracellular fluid within the tumor interstitium is modeled with the help of biphasic mixture theory and a spherical symmetry solution is given as a simpler case. This present model describes the average interstitial fluid pressure (IFP), extracellular fluid velocity (EFV) and flow rate of extracellular fluid, as well as the deformation of the solid phase of the tumor tissue as an immediate cause of extracellular fluid flow. When the interstitial transport is diffusion dominated, an analytical treatment of advection-diffusion-reaction equation finds the overall nutrient distribution. We propose suitable criteria for the formation of necrosis within the tumor interstitium. This study introduces some parameters that represent the nutrient supply from tumor blood vessels into the tumor extracellular space. These transport parameters compete with the reversible nutrient metabolism of the tumor cells present in the interstitium. The present study also shows that the effectiveness factor corresponding to a first order nutrient metabolism may reach beyond unity if the strength of the distributive solute source assumes positive non-zero values. PMID:26851443

  2. Reactive species in non-equilibrium atmospheric-pressure plasmas: Generation, transport, and biological effects

    Science.gov (United States)

    Lu, X.; Naidis, G. V.; Laroussi, M.; Reuter, S.; Graves, D. B.; Ostrikov, K.

    2016-05-01

    Non-equilibrium atmospheric-pressure plasmas have recently become a topical area of research owing to their diverse applications in health care and medicine, environmental remediation and pollution control, materials processing, electrochemistry, nanotechnology and other fields. This review focuses on the reactive electrons and ionic, atomic, molecular, and radical species that are produced in these plasmas and then transported from the point of generation to the point of interaction with the material, medium, living cells or tissues being processed. The most important mechanisms of generation and transport of the key species in the plasmas of atmospheric-pressure plasma jets and other non-equilibrium atmospheric-pressure plasmas are introduced and examined from the viewpoint of their applications in plasma hygiene and medicine and other relevant fields. Sophisticated high-precision, time-resolved plasma diagnostics approaches and techniques are presented and their applications to monitor the reactive species and plasma dynamics in the plasma jets and other discharges, both in the gas phase and during the plasma interaction with liquid media, are critically reviewed. The large amount of experimental data is supported by the theoretical models of reactive species generation and transport in the plasmas, surrounding gaseous environments, and plasma interaction with liquid media. These models are presented and their limitations are discussed. Special attention is paid to biological effects of the plasma-generated reactive oxygen and nitrogen (and some other) species in basic biological processes such as cell metabolism, proliferation, survival, etc. as well as plasma applications in bacterial inactivation, wound healing, cancer treatment and some others. Challenges and opportunities for theoretical and experimental research are discussed and the authors' vision for the emerging convergence trends across several disciplines and application domains is presented to

  3. Multidisciplinary investigation of the fate, transport, and remediation of chlorinated solvents in fractured rocks at the former Naval Air Warfare Center (NAWC): Scientific and management challenges, and strategies for a successful research program

    Science.gov (United States)

    Tiedeman, C. R.; Goode, D. J.; Shapiro, A. M.; Lacombe, P. J.; Chapelle, F. H.; Bradley, P. M.; Imbrigiotta, T. E.; Williams, J. H.; Curtis, G. P.; Hsieh, P. A.

    2008-12-01

    At the former Naval Air Warfare Center (NAWC) in West Trenton NJ, the U.S. Geological Survey, in cooperation with the U.S. Navy and under support from the Strategic Environmental Research and Development Program (SERDP), is investigating the fate, transport, and remediation of trichloroethylene (TCE) and its daughter products in dipping, fractured mudstones underlying the site. TCE concentrations in ground water are as high as ~100 mg/L. Objectives of multidisciplinary research at the NAWC include (1) understanding the physical, chemical, and microbiological processes and properties affecting the fate, transport, and removal of chlorinated solvents in fractured rocks, (2) assessing the efficiency of different remediation methods (pump and treat, natural and enhanced biodegradation), and (3) transferring the results to help remediate other contaminated fractured rock aquifers. There are numerous scientific and technical challenges to meeting these goals, including the extreme spatial variability of flow and transport properties at the NAWC and the complex distribution of contaminants, geochemical constituents, and microorganisms in fractures and the rock matrix. In addition, there are management challenges that are equally important to address in order to achieve a successful research program. These include balancing the requirements of the many parties involved at the site, including researchers, the site owner, and regulatory agencies; and ensuring that limited research funds are directed towards work that addresses the most important scientific questions as well as stakeholder concerns. Strategies for the scientific challenges at NAWC include developing a carefully planned program to characterize spatial variability in rock properties and groundwater constituents so that the data obtained are applicable to solving research questions focused on remediation. Strategies for the management challenges include fostering open lines of communication among all parties and

  4. [How do transport and metabolism affect the biological effects of polycyclic aromatic hydrocarbons?].

    Science.gov (United States)

    Bekki, Kanae; Toriba, Akira; Tang, Ning; Kameda, Takayuki; Takigami, Hidetaka; Suzuki, Go; Hayakawa, Kazuichi

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAHs), some of which are carcinogenic/mutagenic, are generated by combustion of fossil fuels and also released through tanker or oilfield accident to cause a large scale environmental pollution. PAHs concentration in China is especially high in East Asia because of many kinds of generation sources such as coal heating systems, vehicles and factories without exhaust gas/particulate treatment systems. So, the atmospheric pollution caused by PAHs in China has been seriously concerned from the view point of health effects. Like yellow sand and sulfur oxide, PAHs exhausted in China are also transported to Japan. Additionally, strongly mutagenic nitrated PAHs (NPAHs), estrogenic/antiestrogenic PAH hydroxides (PAHOHs) and reactive oxygen species-producing PAH quinones (PAHQs) are formed from PAHs by the chemical reaction during the transport. Furthermore these PAHOHs and PAHQs are produced by the metabolism in animal body. In the biological activities caused by the above PAH derivatives, the structure-activity relationship was observed. In this review, our recent results on the generation of PAH derivatives by atmospheric transport and metabolism are reported. Also, the existing condition of PAHs as atmospheric pollutants is considered. PMID:22382837

  5. The permeability and transport mechanism of graphene quantum dots (GQDs) across the biological barrier

    Science.gov (United States)

    Wang, Xin-Yi; Lei, Rong; Huang, Hong-Duang; Wang, Na; Yuan, Lan; Xiao, Ru-Yue; Bai, Li-Dan; Li, Xue; Li, Li-Mei; Yang, Xiao-Da

    2015-01-01

    As an emerging nanomaterial, graphene quantum dots (GQDs) have shown enormous potential in theranostic applications. However, many aspects of the biological properties of GQDs require further clarification. In the present work, we prepared two sizes of GQDs and for the first time investigated their membrane permeabilities, one of the key factors of all biomedical applications, and transport mechanisms on a Madin Darby Canine Kidney (MDCK) cell monolayer. The experimental results revealed that under ~300 mg L-1, GQDs were innoxious to MDCK and did not affect the morphology and integrity of the cell monolayer. The Papp values were determined to be 1-3 × 10-6 cm s-1 for the 12 nm GQDs and 0.5-1.5 × 10-5 cm s-1 for the 3 nm GQDs, indicating that the 3 nm GQDs are well-transported species while the 12 nm GQDs have a moderate membrane permeability. The transport and uptake of GQDs by MDCK cells were both time and concentration-dependent. Moreover, the incubation of cells with GQDs enhanced the formation of lipid rafts, while inhibition of lipid rafts with methyl-β-cyclodextrin almost eliminated the membrane transport of GQDs. Overall, the experimental results suggested that GQDs cross the MDCK cell monolayer mainly through a lipid raft-mediated transcytosis. The present work has indicated that GQDs are a novel, low-toxic, highly-efficient general carrier for drugs and/or diagnostic agents in biomedical applications.As an emerging nanomaterial, graphene quantum dots (GQDs) have shown enormous potential in theranostic applications. However, many aspects of the biological properties of GQDs require further clarification. In the present work, we prepared two sizes of GQDs and for the first time investigated their membrane permeabilities, one of the key factors of all biomedical applications, and transport mechanisms on a Madin Darby Canine Kidney (MDCK) cell monolayer. The experimental results revealed that under ~300 mg L-1, GQDs were innoxious to MDCK and did not affect

  6. Physics of Transport and Traffic Phenomena in Biology: from molecular motors and cells to organisms

    CERN Document Server

    Chowdhury, D; Nishinari, K; Chowdhury, Debashish; Schadschneider, Andreas; Nishinari, Katsuhiro

    2005-01-01

    Traffic-like collective movements are observed at almost all levels of biological systems. Molecular motor proteins like, for example, kinesin and dynein, which are the vehicles of almost all intra-cellular transport in eukayotic cells, sometimes encounter traffic jam that manifests as a disease of the organism. Similarly, traffic jam of collagenase MMP-1, which moves on the collagen fibrils of the extracellular matrix of vertebrates, has also been observed in recent experiments. Traffic-like movements of social insects like ants and termites on trails are, perhaps, more familiar in our everyday life. Experimental, theoretical and computational investigations in the last few years have led to a deeper understanding of the generic or common physical principles involved in these phenomena. In particular, some of the methods of non-equilibrium statistical mechanics, pioneered almost a hundred years ago by Einstein, Langevin and others, turned out to be powerful theoretical tools for quantitaive analysis of model...

  7. A multiscale analysis of nutrient transport and biological tissue growth in vitro

    KAUST Repository

    O'Dea, R. D.

    2014-10-15

    © The authors 2014. In this paper, we consider the derivation of macroscopic equations appropriate to describe the growth of biological tissue, employing a multiple-scale homogenization method to accommodate explicitly the influence of the underlying microscale structure of the material, and its evolution, on the macroscale dynamics. Such methods have been widely used to study porous and poroelastic materials; however, a distinguishing feature of biological tissue is its ability to remodel continuously in response to local environmental cues. Here, we present the derivation of a model broadly applicable to tissue engineering applications, characterized by cell proliferation and extracellular matrix deposition in porous scaffolds used within tissue culture systems, which we use to study coupling between fluid flow, nutrient transport, and microscale tissue growth. Attention is restricted to surface accretion within a rigid porous medium saturated with a Newtonian fluid; coupling between the various dynamics is achieved by specifying the rate of microscale growth to be dependent upon the uptake of a generic diffusible nutrient. The resulting macroscale model comprises a Darcy-type equation governing fluid flow, with flow characteristics dictated by the assumed periodic microstructure and surface growth rate of the porous medium, coupled to an advection-reaction equation specifying the nutrient concentration. Illustrative numerical simulations are presented to indicate the influence of microscale growth on macroscale dynamics, and to highlight the importance of including experimentally relevant microstructural information to correctly determine flow dynamics and nutrient delivery in tissue engineering applications.

  8. Cryptococcus neoformans dual GDP-mannose transporters and their role in biology and virulence.

    Science.gov (United States)

    Wang, Zhuo A; Griffith, Cara L; Skowyra, Michael L; Salinas, Nichole; Williams, Matthew; Maier, Ezekiel J; Gish, Stacey R; Liu, Hong; Brent, Michael R; Doering, Tamara L

    2014-06-01

    Cryptococcus neoformans is an opportunistic yeast responsible for lethal meningoencephalitis in humans. This pathogen elaborates a polysaccharide capsule, which is its major virulence factor. Mannose constitutes over one-half of the capsule mass and is also extensively utilized in cell wall synthesis and in glycosylation of proteins and lipids. The activated mannose donor for most biosynthetic reactions, GDP-mannose, is made in the cytosol, although it is primarily consumed in secretory organelles. This compartmentalization necessitates specific transmembrane transporters to make the donor available for glycan synthesis. We previously identified two cryptococcal GDP-mannose transporters, Gmt1 and Gmt2. Biochemical studies of each protein expressed in Saccharomyces cerevisiae showed that both are functional, with similar kinetics and substrate specificities in vitro. We have now examined these proteins in vivo and demonstrate that cells lacking Gmt1 show significant phenotypic differences from those lacking Gmt2 in terms of growth, colony morphology, protein glycosylation, and capsule phenotypes. Some of these observations may be explained by differential expression of the two genes, but others suggest that the two proteins play overlapping but nonidentical roles in cryptococcal biology. Furthermore, gmt1 gmt2 double mutant cells, which are unexpectedly viable, exhibit severe defects in capsule synthesis and protein glycosylation and are avirulent in mouse models of cryptococcosis.

  9. Effects of spray-irrigated treated effluent on water quantity and quality, and the fate and transport of nitrogen in a small watershed, New Garden Township, Chester County, Pennsylvania

    Science.gov (United States)

    Schreffler, Curtis L.; Galeone, Daniel G.; Veneziale, John M.; Olson, Leif E.; O'Brien, David L.

    2005-01-01

    An increasing number of communities in Pennsylvania are implementing land-treatment systems to dispose of treated sewage effluent. Disposal of treated effluent by spraying onto the land surface, instead of discharging to streams, may recharge the ground-water system and reduce degradation of stream-water quality. The U.S. Geological Survey (USGS), in cooperation with the Pennsylvania Department of Environmental Protection (PaDEP) and the Chester County Water Resources Authority (CCWRA) and with assistance from the New Garden Township Sewer Authority, conducted a study from October 1997 through December 2001 to assess the effects of spray irrigation of secondary treated sewage effluent on the water quantity and quality and the fate and transport of nitrogen in a 38-acre watershed in New Garden Township, Chester County, Pa. On an annual basis, the spray irrigation increased the recharge to the watershed. Compared to the annual recharge determined for the Red Clay Creek watershed above the USGS streamflow-gaging station (01479820) near Kennett Square, Pa., the spray irrigation increased annual recharge in the study watershed by approximately 8.8 in. (inches) in 2000 and 4.3 in. in 2001. For 2000 and 2001, the spray irrigation increased recharge 65-70 percent more than the recharge estimates determined for the Red Clay Creek watershed. The increased recharge was equal to 30-39 percent of the applied effluent. The spray-irrigated effluent increased base flow in the watershed. The magnitude of the increase appeared to be related to the time of year when the application rates increased. During the late fall through winter and into the early spring period, when application rates were low, base flow increased by approximately 50 percent over the period prior to effluent application. During the early spring through summer to the late fall period, when application rates were high, base flow increased by approximately 200 percent over the period prior to effluent application

  10. Biological restoration of major transportation facilities domestic demonstration and application project (DDAP): technology development at Sandia National Laboratories.

    Energy Technology Data Exchange (ETDEWEB)

    Ramsey, James L., Jr. (.,; .); Melton, Brad; Finley, Patrick; Brockman, John; Peyton, Chad E.; Tucker, Mark David; Einfeld, Wayne; Griffith, Richard O.; Brown, Gary Stephen; Lucero, Daniel A.; Betty, Rita G.; McKenna, Sean Andrew; Knowlton, Robert G.; Ho, Pauline

    2006-06-01

    The Bio-Restoration of Major Transportation Facilities Domestic Demonstration and Application Program (DDAP) is a designed to accelerate the restoration of transportation nodes following an attack with a biological warfare agent. This report documents the technology development work done at SNL for this DDAP, which include development of the BROOM tool, an investigation of surface sample collection efficiency, and a flow cytometry study of chlorine dioxide effects on Bacillus anthracis spore viability.

  11. Fate of pesticides in field ditches: the TOXSWA simulation model

    NARCIS (Netherlands)

    Adriaanse, P.I.

    1996-01-01

    The TOXSWA model describes the fate of pesticides entering field ditches by spray drift, atmospheric deposition, surface run-off, drainage or leaching. It considers four processes: transport, transformation, sorption and volatilization. Analytical andnumerical solutions corresponded well. A sample s

  12. The fate and importance of radionuclides produced in nuclear events

    International Nuclear Information System (INIS)

    Some of the major program at the Bio-Medical Division concerned with the fate and importance of the fission products, the radionuclides induced in the device materials, the radionuclides induced in the environment surrounding the device, and the tritium produced in Plowshare cratering events will be discussed. These programs include (1) critical unknowns in predicting organ and body burdens from radionuclides produced in cratering events; (2) the analysis with a high-resolution solid state gamma ray spectrometer of radionuclides in complex biological and environmental samples; (3) the characterization of radioactive particles from cratering detonation; (4) the biological availability to beagles, pigs and goats of radionuclides in Plowshare debris; (5) the biological availability to aquatic animals of radionuclides in Plowshare and other nuclear debris and the biological turnover of critical nuclides in specific aquatic animals; (6) the biological availability of Plowshare and other nuclear debris radionuclides to dairy cows and the transplacental transport of debris radionuclides in the dairy cow; (7) the persistence and behavior of radionuclides, particularly tritium, at sites of Plowshare and other nuclear detonations; and (8) somatic effects of Low Dose Radiation: Chromosome studies. (author)

  13. Nearshore transport processes affecting the dilution and fate of energy-related contaminants. Progress report, October 1, 1979-September 30, 1980

    International Nuclear Information System (INIS)

    Research was conducted on physical oceanograhic processes off the Georgia Coast. Spatral variations in momentum and salt flux were measured to determine their importance in generating flow and salt transport. Analyses of data are presently underway

  14. Nearshore transport processes affecting the dilution and fate of energy-related contaminants. Progress report, October 1, 1979-September 30, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Blanton, J. O.

    1980-07-15

    Research was conducted on physical oceanograhic processes off the Georgia Coast. Spatral variations in momentum and salt flux were measured to determine their importance in generating flow and salt transport. Analyses of data are presently underway.

  15. The Environmental Fate Simulator: A tool for predicting the degradation pathways of organic chemicals in groundwater aquifers

    Science.gov (United States)

    Development of the Environmental Fate Simulator (EFS): • High throughput computational system for providing molecular and environmental descriptors for consumption by EF&T models Requires:  Knowledge of the process science controlling chemical fate and transport  The abil...

  16. Report on the remedial investigation of Bear Creek Valley at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee. Volume 4: Appendix E -- Valley-wide fate and transport report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    This Remedial Investigation (RI) Report characterizes the nature and extent of contamination, evaluates the fate and transport of contaminants, and assesses risk to human health and the environment resulting from waste disposal and other US Department of Energy (DOE) operations in Bear Creek Valley (BCV). BCV, which is located within the DOE Oak Ridge Reservation (ORR) encompasses multiple waste units containing hazardous and radioactive wastes arising from operations at the adjacent Oak Ridge Y-12 Plant. The primary waste units discussed in this RI Report are the S-3 Site, Oil Landfarm (OLF), Boneyard/Burnyard (BYBY), Sanitary Landfill 1 (SL 1), and Bear Creek Burial Grounds (BCBG). These waste units, plus the contaminated media resulting from environmental transport of the wastes from these units, are the subject of this RI. This BCV RI Report represents the first major step in the decision-making process for the BCV watershed. The RI results, in concert with the follow-on FS will form the basis for the Proposed Plan and Record of Decision for all BCV sites. This comprehensive decision document process will meet the objectives of the watershed approach for BCV. Appendix E addresses contaminant releases and migration pathways from a valley-wide perspective and provides estimates of changes in contaminant fluxes in BCV.

  17. Report on the remedial investigation of Bear Creek Valley at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee. Volume 4: Appendix E -- Valley-wide fate and transport report

    International Nuclear Information System (INIS)

    This Remedial Investigation (RI) Report characterizes the nature and extent of contamination, evaluates the fate and transport of contaminants, and assesses risk to human health and the environment resulting from waste disposal and other US Department of Energy (DOE) operations in Bear Creek Valley (BCV). BCV, which is located within the DOE Oak Ridge Reservation (ORR) encompasses multiple waste units containing hazardous and radioactive wastes arising from operations at the adjacent Oak Ridge Y-12 Plant. The primary waste units discussed in this RI Report are the S-3 Site, Oil Landfarm (OLF), Boneyard/Burnyard (BYBY), Sanitary Landfill 1 (SL 1), and Bear Creek Burial Grounds (BCBG). These waste units, plus the contaminated media resulting from environmental transport of the wastes from these units, are the subject of this RI. This BCV RI Report represents the first major step in the decision-making process for the BCV watershed. The RI results, in concert with the follow-on FS will form the basis for the Proposed Plan and Record of Decision for all BCV sites. This comprehensive decision document process will meet the objectives of the watershed approach for BCV. Appendix E addresses contaminant releases and migration pathways from a valley-wide perspective and provides estimates of changes in contaminant fluxes in BCV

  18. Fate of pollutants

    International Nuclear Information System (INIS)

    A literature review is presented of the fate of pollutants in sediment and water systems. Topics of discussion include the following: modeling, observations, and general studies; chlorinated xenobiotic chemicals; nonchlorinated xenobiotic chemicals; pesticides; heavy metals; and radionuclides

  19. Atrazine dissipation in s-Triazine-adapted and Non-adapted soil from Coloroado and Mississippi: Implications of enhanced degradation on atrazine fate and transport parameters

    Science.gov (United States)

    Modelers and regulatory agencies typically use default atrazine half-life values of 60 to 120 d to predict the herbicide’s transport; however, if atrazine persistence is reduced in soils exhibiting enhanced degradation, but modelers continue to use historic atrazine persistence estimates, then accur...

  20. Coupling and Testing the Fate and Transport of Heavy Metals and Other Ionic Species in a Groundwater Setting at Oak Ridge, TN - 13498

    International Nuclear Information System (INIS)

    Historical data show that heavy metals (including mercury) were released from Y -12 National Security Complex (NSC) at Oak Ridge, Tennessee, to the surrounding environments during its operation in 1950's. Studies have also shown that metals accumulated in the soil, rock, and groundwater, and are, at the present time, sources of contamination to nearby rivers and creeks (e.g., East Fork Poplar Creek, Bear Creek). For instance, mercury (Hg), zinc (Zn), cadmium (Cd) and lead (Pb) have been found and reported on the site groundwater. The groundwater type at the site is Ca-Mg-HCO3. This paper presents a modeling application of PHREEQC, a model that simulates geochemical processes and couples them to flow and transport settings. The objective was to assess the capability of PHREEQC to simulate the transport of ionic species in groundwater at Oak Ridge, Tennessee; data were available from core holes and monitoring wells over a 736-m distance, within 60-300 m depths. First, predictions of the transport of major ionic species (i.e., Ca2+ and Mg2+) in the water were made between monitoring wells and for GW-131. Second, the model was used to assess hypotheses under two scenarios of transport for Zn, Cd, Pb and Hg, in Ca-Mg-HCO3 water, as influenced by the following solid-liquid interactions: a) the role of ion exchange and b) the role of both ion exchange and sorption, the latter via surface complexation with Fe(OH)3. The transport scenario with ion exchange suggests that significant ion exchange is expected to occur for Zn, Cd and Pb concentrations, with no significant impact on Hg, within the first 100 m. Predictions match the expected values of the exchange coefficients relative to Ca2+ and Mg2+ (e.g., KCa/Zn = KCa/Cd > KCa/Pb > KCa/Hg). The scenario with both ion exchange and sorption does affect the concentrations of Zn and Cd to a small extent within the first 100 m, but does more meaningfully reduce the concentration of Pb, within the same distance, and also decreases

  1. The Transport and Fate of Particulate Material in a Shallow, Turbid Estuary: Seasonal and Decadal Characteristics from 7-Be and 210-Pb Techniques

    Science.gov (United States)

    Booth, J. G.; McKee, Brent A.; Meriwether, John R.

    1999-01-01

    Seasonal and long-term sediment transport characteristics were examined using surficial sediment 7-Be inventories and the down core distribution of excess 210-Pb. Data were collected in the Barataria Basin, LA over the fifteen month period from September 1995 to January 1997. Seasonal sediment transport rates based on 7-Be inventories ranged from -1.6E3 to 1.42E4 g/m2/yr, whereas decadal sediment burial rates based on excess 210-Pb ranged from 3.83E2 to 2.00E3 g/m2/yr, respectively. Seasonal transport characteristics vary with location in the basin and appear to be largely controlled by seasonal weather patterns and the associated winds. It appears that, at less sheltered locations, long term rates of sediment burial are controlled by frontal passages and the associated strong northerly and southerly component winds; whereas at fetch limited locations burial rates are likely controlled by stronger weather events such as tropical storms and hurricanes.

  2. Fractional derivatives in the transport of drugs across biological materials and human skin

    Science.gov (United States)

    Caputo, Michele; Cametti, Cesare

    2016-11-01

    The diffusion of drugs across a composite structure such as a biological membrane is a rather complex phenomenon, because of its inhomogeneous nature, yielding a diffusion rate and a drug solubility strongly dependent on the local position across the membrane itself. These problems are particularly strengthened in composite structures of a considerable thickness like, for example, the human skin, where the high heterogeneity provokes the transport through different simultaneous pathways. In this note, we propose a generalization of the diffusion model based on Fick's 2nd equation by substituting a diffusion constant by means of the memory formalism approach (diffusion with memory). In particular, we employ two different definitions of the fractional derivative, i.e., the usual Caputo fractional derivative and a new definition recently proposed by Caputo and Fabrizio. The model predictions have been compared to experimental results concerning the permeation of two different compounds through human skin in vivo, such as piroxicam, an anti-inflammatory drug, and 4-cyanophenol, a test chemical model compound. Moreover, we have also considered water penetration across human stratum corneum and the diffusion of an antiviral agent employed as model drugs across the skin of male hairless rats. In all cases, a satisfactory good agreement based on the diffusion with memory has been found. However, the model based on the new definition of fractional derivative gives a better description of the experimental data, on the basis of the residuals analysis. The use of the new definition widens the applicability of the fractional derivative to diffusion processes in highly heterogeneous systems.

  3. Microscopic studies of the fate of charges in organic semiconductors: Scanning Kelvin probe measurements of charge trapping, transport, and electric fields in p- and n-type devices

    Science.gov (United States)

    Smieska, Louisa Marion

    Organic semiconductors could have wide-ranging applications in lightweight, efficient electronic circuits. However, several fundamental questions regarding organic electronic device behavior have not yet been fully addressed, including the nature of chemical charge traps, and robust models for injection and transport. Many studies focus on engineering devices through bulk transport measurements, but it is not always possible to infer the microscopic behavior leading to the observed measurements. In this thesis, we present scanning-probe microscope studies of organic semiconductor devices in an effort to connect local properties with local device behavior. First, we study the chemistry of charge trapping in pentacene transistors. Working devices are doped with known pentacene impurities and the extent of charge trap formation is mapped across the transistor channel. Trap-clearing spectroscopy is employed to measure an excitation of the pentacene charge trap species, enabling identification of the degradationrelated chemical trap in pentacene. Second, we examine transport and trapping in peryelene diimide (PDI) transistors. Local mobilities are extracted from surface potential profiles across a transistor channel, and charge injection kinetics are found to be highly sensitive to electrode cleanliness. Trap-clearing spectra generally resemble PDI absorption spectra, but one derivative yields evidence indicating variation in trap-clearing mechanisms for different surface chemistries. Trap formation rates are measured and found to be independent of surface chemistry, contradicting a proposed silanol trapping mechanism. Finally, we develop a variation of scanning Kelvin probe microscopy that enables measurement of electric fields through a position modulation. This method avoids taking a numeric derivative of potential, which can introduce high-frequency noise into the electric field signal. Preliminary data is presented, and the theoretical basis for electric field

  4. Inhibition of post-translational N-glycosylation by HRD1 that controls the fate of ABCG5/8 transporter

    OpenAIRE

    Suzuki, Shingo; Shuto, Tsuyoshi; Sato, Takashi; Kaneko, Masayuki; Takada, Tappei; Suico, Mary Ann; Cyr, Douglas M; Suzuki, Hiroshi; Kai, Hirofumi

    2014-01-01

    N-glycosylation of proteins in endoplasmic reticulum is critical for protein quality control. We showed here a post-translational N-glycosylation affected by the HRD1 E3 ubiquitin ligase. Both WT- and E3-defective C329S-HRD1 decreased the level of high mannose form of ABCG8, a protein that heterodimerizes with ABCG5 to control sterol balance. Meanwhile, HRD1 increased the non-glycosylated ABCG8 regardless of its E3 activity, thereby suppressing full maturation of ABCG5/8 transporter. Pulse ch...

  5. Biologic

    CERN Document Server

    Kauffman, L H

    2002-01-01

    In this paper we explore the boundary between biology and the study of formal systems (logic). In the end, we arrive at a summary formalism, a chapter in "boundary mathematics" where there are not only containers but also extainers ><, entities open to interaction and distinguishing the space that they are not. The boundary algebra of containers and extainers is to biologic what boolean algebra is to classical logic. We show how this formalism encompasses significant parts of the logic of DNA replication, the Dirac formalism for quantum mechanics, formalisms for protein folding and the basic structure of the Temperley Lieb algebra at the foundations of topological invariants of knots and links.

  6. Understanding the transport of Patagonian dust and its influence on marine biological activity in the South Atlantic Ocean

    OpenAIRE

    Johnson, M. S.; Meskhidze, N.; Kiliyanpilakkil, V. P.; Gassó, S.

    2010-01-01

    The supply of bioavailable iron to the high-nitrate low-chlorophyll (HNLC) waters of the Southern Ocean through atmospheric pathways could stimulate phytoplankton blooms and have major implications for the global carbon cycle. In this study, model results and remotely-sensed data are analyzed to examine the horizontal and vertical transport pathways of Patagonian dust and quantify the effect of iron-laden mineral dust deposition on marine biological productivity in the surface waters o...

  7. Understanding the transport of Patagonian dust and its influence on marine biological activity in the South Atlantic Ocean

    OpenAIRE

    Johnson, M. S.; Meskhidze, N.; Kiliyanpilakkil, V. P.; Gassó, S.

    2011-01-01

    The supply of bioavailable iron to the high-nitrate low-chlorophyll (HNLC) waters of the Southern Ocean through atmospheric pathways could stimulate phytoplankton blooms and have major implications for the global carbon cycle. In this study, model results and remotely-sensed data are analyzed to examine the horizontal and vertical transport pathways of Patagonian dust and quantify the effect of iron-laden mineral dust deposition on marine biological productivity in the surface waters of the S...

  8. Software for fitting and simulating fate and transport of dense colloids and biocolloids in one-dimensional porous media: Re-introducing ColloidFit.

    Science.gov (United States)

    Katzourakis, Vasileios; Chrysikopoulos, Constantinos

    2016-04-01

    The present work re-introduces ColloidFit, which is an autonomous, modular, multipurpose fitting software for dense colloid and biocolloid transport phenomena in porous media. The initial version of ColloidFit, introduced by Sim and Chrysikopoulos (1995), was substantially improved and combined with a relatively intuitive and easy to use graphical user interface. The re-introduced ColloidFit can simulate the migration of suspended colloid or biocolloid particles in one-dimensional, water saturated, homogeneous porous media with uniform flow, accounting for non-equilibrium attachment onto the solid matrix, as well as gravitational effects. Furthermore, the improved ColloidFit software employs a variety of non-equilibrium, linear and nonlinear models for the simulation of colloid attachment onto a solid matrix under batch experimental conditions. The re-introduced ColloidFit uses the state of the art fitting software "Pest" to estimate unknown model parameter values, together with their 95% confidence intervals. Pest is a model-independent parameter estimation software capable of adjusting model parameters, so that discrepancies between model-generated data and the corresponding experimental measurements are reduced to a user preselected minimum. The fitting process is graphed and displayed in real time. The user is allowed to overview every step of the fitting progress, and if needed to change the initial parameter values. The re-introduced ColloidFit software is expected to make the fitting process of colloid and biocolloid transport data, just a simple task.

  9. Estimates of direct biological transport of radioactive waste in the deep sea with special reference to organic carbon budgets

    International Nuclear Information System (INIS)

    Calculations can be made for the maximum theoretical transport of pollutants such as radionuclides by movement of organisms out of a deep-sea benthic boundary layer dump site based on a presumption of a steady state organic carbon budget and estimated biological concentration factors. A calculated flux rate depends on the difference between a limiting input of organic matter and that carbon used by the biota or accumulating in the sediment. On average, the potential biological mass transport is low compared to physical transport. Exceptions to this generalization are possible in the far field after spatial gradients are obliterated or if natural mass migrations or periodic spawning concentrations occur in the near field. Biologically mediated fluxes of contaminants due to mixing of sediments by bioturbation or vertical flux due to scavenging by sinking particles are significant for movements of pollutants to and from sediments. These pathways contribute to the direct input of contaminants into food webs which may contain harvestable species. These fluxes are unimportant for mass transfers in the ocean but they determine the exposure of critical groups to contaminants

  10. Denitrification-Coupled Iron(II) Oxidation: A Key Process Regulating the Fate and Transport of Nitrate, Phosphate, and Arsenic in a Wastewater-Contaminated Aquifer

    Science.gov (United States)

    Smith, R. L.; Kent, D. B.; Repert, D. A.; Hart, C. P.

    2007-12-01

    Denitrification in the subsurface is often viewed as a heterotrophic process. However, some denitrifiers can also utilize inorganic electron donors. In particular, Fe(II), which is common in many aquifers, could be an important reductant for contaminant nitrate. Anoxic iron oxidation would have additional consequences, including decreased mobility for species like arsenic and phosphate, which bind strongly to hydrous Fe(III) oxide. A study was conducted in a wastewater contaminant plume on Cape Cod to assess the potential for denitrification- coupled Fe(II) oxidation. Previous changes in wastewater disposal upgradient of the study area had resulted in nitrate being transported into a portion of the anoxic zone of the plume and decreased concentrations of Fe(II), phosphate, and arsenic. A series of anoxic tracers (groundwater + nitrate + bromide) were injected into the unaffected, Fe(II)-containing zone under natural gradient conditions. Denitrification was stimulated within 1 m of transport (4 days) for both low and high (100 & 1000 μM) nitrate additions, initially producing stiochiometric quantities of nitrous oxide (>300 μM N) and trace amounts of nitrite. Subsequent injections at the same site reduced nitrate even more rapidly and produced less nitrous oxide, especially over longer transport distances. Fe(II) and nitrate concentrations decreased together and this was accompanied by an increase in colloidal Fe(III) and decreases in pH, total arsenic, and phosphate concentrations. All plume constituents returned to background levels several weeks after the tracer tests were completed. Groundwater microorganisms collected on filters during the tracer test rapidly and immediately reduced nitrite and oxidized Fe(II) in 3-hr laboratory incubations. Several pure cultures of Fe(II)-oxidizing denitrifying bacteria were isolated from core material and subsequently characterized. All of the isolates were mixotrophic, simultaneously oxidizing organic carbon and Fe

  11. Multidisciplinary Studies of the Fate and Transport of Contaminants in Ground Water at the U.S. Geological Survey Cape Cod Toxic Substances Hydrology Program Research Site, Massachusetts

    Science.gov (United States)

    Leblanc, D. R.; Smith, R. L.; Kent, D. B.; Barber, L. B.; Harvey, R. W.

    2008-12-01

    The U.S. Geological Survey conducts multidisciplinary research on the physical, chemical, and microbiological processes affecting ground-water contaminants of global concern at its Cape Cod Toxic Substances Hydrology Program site in Massachusetts, USA. The work centers on a 6-kilometer-long plume of treated wastewater in a glacial sand and gravel aquifer. The plume is characterized by distinct geochemical zones caused by the biodegradation of organic materials in treated wastewater that was disposed to the aquifer by rapid infiltration during the period 1936-95. A core group of hydrogeologists, geochemists, microbiologists, and geophysicists has been involved in the research effort for more than two decades. The effort has been enhanced by stable funding, a readily accessible site, a relatively simple hydrologic setting, and logistical support from an adjacent military base. The research team uses a three-part approach to plan and conduct research at the site. First, detailed spatial and temporal monitoring of the plume since the late 1970s provides field evidence of important contaminant-transport processes and provides the basis for multidisciplinary, process-oriented studies. Second, ground-water tracer experiments are conducted in various geochemical zones in the plume to study factors that control the rate and extent of contaminant transport. Several arrays of multilevel sampling devices, including an array with more than 15,000 individual sampling points, are used to conduct these experiments. Plume-scale (kilometers) and tracer-test-scale (1- 100 meters) studies are complemented by laboratory experiments and mathematical modeling of flow and reactive transport. Third, results are applied to the treated-wastewater plume, other contaminant plumes at the military base, and other sites nationally to evaluate the applicability of the findings and to point toward further research. Examples of findings to date include that (1) macrodispersivity can be related to

  12. Two- and Three-Dimensional Depiction of Subsurface Geology Using Commercial Software for Support of Groundwater Contaminant Fate and Transport Analysis - 13345

    Energy Technology Data Exchange (ETDEWEB)

    Ivarson, Kristine A. [North Wind, Inc. Richland, Washington 99352 (United States); Miller, Charles W.; Arola, Craig C. [CH2M HILL Plateau Remediation Company, Richland, Washington 99352 (United States)

    2013-07-01

    Groundwater contamination by hexavalent chromium and other nuclear reactor operation-related contaminants has resulted in the need for groundwater remedial actions within the Hanford Site reactor areas (the Hanford Site 100 Area). The large geographic extent of the resultant contaminant plumes requires an extensive level of understanding of the aquifer structure, characteristics, and configuration to support assessment and design of remedial alternatives within the former 100-D, 100-H, and 100-K reactor areas. The authors have prepared two- and three-dimensional depictions of the key subsurface geologic structures at two Hanford Site reactor operable units (100-K and 100-D/H). These depictions, prepared using commercial-off-the-shelf (COTS) visualization software, provide a basis for expanding the understanding of groundwater contaminant migration pathways, including identification of geologically-defined preferential groundwater flow pathways. These identified preferential flow pathways support the conceptual site model and help explain both historical and current contaminant distribution and transport. (authors)

  13. A biomimetic DNA-based channel for the ligand-controlled transport of charged molecular cargo across a biological membrane

    Science.gov (United States)

    Burns, Jonathan R.; Seifert, Astrid; Fertig, Niels; Howorka, Stefan

    2016-02-01

    Biological ion channels are molecular gatekeepers that control transport across cell membranes. Recreating the functional principle of such systems and extending it beyond physiological ionic cargo is both scientifically exciting and technologically relevant to sensing or drug release. However, fabricating synthetic channels with a predictable structure remains a significant challenge. Here, we use DNA as a building material to create an atomistically determined molecular valve that can control when and which cargo is transported across a bilayer. The valve, which is made from seven concatenated DNA strands, can bind a specific ligand and, in response, undergo a nanomechanical change to open up the membrane-spanning channel. It is also able to distinguish with high selectivity the transport of small organic molecules that differ by the presence of a positively or negatively charged group. The DNA device could be used for controlled drug release and the building of synthetic cell-like or logic ionic networks.

  14. EMT and MET as paradigms for cell fate switching

    Institute of Scientific and Technical Information of China (English)

    Jiekai Chen; Qingkai Han; Duanqing Pei

    2012-01-01

    Cell fate determination is a major unsolved problem in cell and developmental biology,The discovery of reprogramming by pluripotent factors offers a rational system to investigate the molecular mechanisms associated with cell fate decisions.The idea that reprogramming of fibroblasts starts with a mesenchymal-epithelial transition (MET) suggests that the process is perhaps a reversal of epithelial to mesenchymal transition (EMT) found frequently during early embryogenesis,As such,we believe that investigations into MET-EMT may yield detailed molecular insights into cell fate decisions,not only for the switching between epithelial and mesenchymal cells,but also other cell types.

  15. Monitoring of Emerging and Legacy Contaminants in Groundwater and Tap Water of the Karst Region in Northern Puerto Rico for Assessment of Sources and Fate and Transport Processes

    Science.gov (United States)

    Padilla, I. Y.; Cotto, I.; Torres, P. M.

    2014-12-01

    tap water (30%). Results indicated that most CVOCs on tap water come from groundwater sources. Spatial-temporal analysis of CVOC data shows that transport through karst system is highly heterogeneous variable, and reflect high capacity of the system to store and slowly release contaminants through rate-limited mass transport process.

  16. Origin, transport and fate of the dissolved organic matter produced in the watershed of the Paraíba do Sul River, Brazil.

    Science.gov (United States)

    Marques da Silva Junior, Jomar; Soares Gonçalves Serafim, Tassiana; Gomes de Almeida, Marcelo; Dittmar, Thorsten; de Rezende, Carlos Eduardo

    2015-04-01

    The Paraíba do Sul River (PSR) is an important river from Southeastern Brazil that flows through the states of São Paulo, Minas Gerais and Rio de Janeiro. The PSR is responsible for the water supply of over 14 million of the habitants. Due the human occupation and anthropic pressure, only 8% of it is original forest cover remains in the form of small fragmented patches. The remaining of the basin is mostly covered by grasses, such as pasture and sugar cane. Isotopic studies allows the monitoring of ecosystem changes and promotes specific links between ecology, land use and biogeochemical processes. We investigated the isotopic composition of the dissolved organic matter (DOM) in PSR. Our objective was to identify how extensive land use changes, from forest (C3 Plants) to pasture and sugar cane (C4 Plants), have affected river biogeochemistry of organic matter transported by PSR. Water samples were collected at 24 sites along the main channel of the PSR, 14 sites samples at the tributaries and 21 sites samples in the estuarine and marine environmental until 35km of the coast. Sampling was performed in the wet season of the 2013 and the dry season of the 2013. The fluvial and estuarine samples were processed with conventional filtration and the marine samples were processed with the cross-flow filtration. The dissolved organic matter (DOM) was isolated by solid-phase extraction (SPE) with the PPL cartridges (Styrene divinyl benzene polymer). Isotope measurements, organic carbon and nitrogen concentration were performed with a isotope-ratio mass spectrometry (Thermo Finningan). The 13C and the 15N values ranged from -20.0‰ and -29.0‰, and from -0.80 to 4.59 respectively, while the (C/N)a ratio varied between 8 and 41. The 13C were depleted in 13C at the river samples from the wet season, and in the estuary and marine areas as well. The 13C average values observed during the wet season in the PSR and in the estuarine samples are close to those

  17. Land-cover effects on the fate and transport of surface-applied antibiotics and 17-beta-estradiol on a sandy outwash plain, Anoka County, Minnesota, 2008–09

    Science.gov (United States)

    Trost, Jared J.; Kiesling, Richard L.; Erickson, Melinda L.; Rose, Peter J.; Elliott, Sarah M.

    2013-01-01

    A plot-scale field experiment on a sandy outwash plain in Anoka County in east-central Minnesota was used to investigate the fate and transport of two antibiotics, sulfamethazine (SMZ) and sulfamethoxazole (SMX), and a hormone, 17-beta-estradiol (17BE), in four land-cover types: bare soil, corn, hay, and prairie. The SMZ, SMX, and 17BE were applied to the surface of five plots of each land-cover type in May 2008 and again in April 2009. The cumulative application rate was 16.8 milligrams per square meter (mg/m2) for each antibiotic and 0.6 mg/m2 for 17BE. Concentrations of each chemical in plant-tissue, soil, soil-water, and groundwater samples were determined by using enzyme-linked immunosorbent assay (ELISA) kits. Soil-water and groundwater sampling events were scheduled to capture the transport of SMZ, SMX, and 17BE during two growing seasons. Soil and plant-tissue sampling events were scheduled to identify the fate of the parent chemicals of SMZ, SMX, and 17BE in these matrices after two chemical applications. Areal concentrations (mg/m2) of SMZ and SMX in soil tended to decrease in prairie plots in the 8 weeks after the second chemical application, from April 2009 to June 2009, but not in other land-cover types. During these same 8 weeks, prairie plots produced more aboveground biomass and had extracted more water from the upper 125 centimeters of the soil profile compared to all other land-cover types. Areal concentrations of SMZ and SMX in prairie plant tissue did not explain the temporal changes in areal concentrations of these chemicals in soil. The areal concentrations of SMZ and SMX in the aboveground plant tissues in June 2009 and August 2009 were much lower, generally two to three orders of magnitude, than the areal concentrations of these chemicals in soil. Pooling all treatment plot data, the median areal concentration of SMZ and SMX in plant tissues was 0.01 and 0.10 percent of the applied chemical mass compared to 22 and 12 percent in soil

  18. Impact of the regional climate and substance properties on the fate and atmospheric long-range transport of persistent organic pollutants – examples of DDT and γ-HCH

    Directory of Open Access Journals (Sweden)

    J. Feichter

    2005-12-01

    Full Text Available A global multicompartment model which is based on a 3-D atmospheric general circulation model (ECHAM5 coupled to 2-D soil, vegetation and sea surface mixed layer reservoirs, is used to simulate the atmospheric transports and total environmental fate of dichlorodiphenyltrichloroethane (DDT and γ-hexachlorocyclohexane (γ-HCH, lindane. Emissions into the model world reflect the substance's agricultural usage in 1980 and 1990 and same amounts in sequential years are applied. Four scenarios of DDT usage and atmospheric decay and one scenario of γ-HCH are studied over a decade. The global environment is predicted to be contaminated by the substances within ca. 2 a (years. DDT reaches quasi-steady state within 3–4 a in the atmosphere and vegetation compartments, ca. 6 a in the sea surface mixed layer and near to or slightly more than 10 a in soil. Lindane reaches quasi-steady state in the atmosphere and vegetation within 2 a, in soils within 8 years and near to or slightly more than 10 a and in the sea surface mixed layer. The substances' differences in environmental behaviour translate into differences in the compartmental distribution and total environmental residence time, τoverall. τoverall≈0.8 a for γ-HCH's and ≈1.0–1.3 a for the various DDT scenarios. Both substances' distributions are predicted to migrate in northerly direction, 5–12° for DDT and 6.7° for lindane between the first and the tenth year in the environment. Cycling in various receptor regions is a complex superposition of influences of regional climate, advection, and the substance's physico-chemical properties. As a result of these processes the model simulations show that remote boreal regions are not necessarily less contaminated than tropical receptor regions. Although the atmosphere accounts for only 1% of the total contaminant burden, transport and transformation in the atmosphere is key for the distribution in other compartments. Hence, besides the physico

  19. The international transportation of zoo animals: conserving biological diversity and protecting animal welfare

    Directory of Open Access Journals (Sweden)

    Peter Linhart†

    2008-03-01

    Full Text Available Issues pertaining to the long distance transportation of animals are examined according to the aspirations of the world’s zoo community. Guidance comes from the World Association of Zoos and Aquariums (WAZA, the civil society organisation that provides ‘leadership and support for zoos, aquariums and partner organisations of the world in animal care and welfare, conservation of biodiversity, environmental education and global sustainability’. The authors describe why it is necessary to transport zoo animals over long distances and how animal welfare can be protected during the process. Transportation of animals among zoos is essential for the cooperative breeding programmes undertaken for the ex situ conservation of wildlife with the help of WAZA studbooks. The challenge is to satisfy the entwined ethical imperatives of safeguarding animal welfare and protecting biodiversity.

  20. Fate Mapping Mammalian Corneal Epithelia.

    Science.gov (United States)

    Richardson, Alexander; Wakefield, Denis; Di Girolamo, Nick

    2016-04-01

    The anterior aspect of the cornea consists of a stratified squamous epithelium, thought to be maintained by a rare population of stem cells (SCs) that reside in the limbal transition zone. Although migration of cells that replenish the corneal epithelium has been studied for over a century, the process is still poorly understood and not well characterized. Numerous techniques have been employed to examine corneal epithelial dynamics, including visualization by light microscopy, the incorporation of vital dyes and DNA labels, and transplantation of genetically marked cells that have acted as cell and lineage beacons. Modern-day lineage tracing utilizes molecular methods to determine the fate of a specific cell and its progeny over time. Classically employed in developmental biology, lineage tracing has been used more recently to track the progeny of adult SCs in a number of organs to pin-point their location and understand their movement and influence on tissue regeneration. This review highlights key discoveries that have led researchers to develop cutting-edge genetic tools to effectively and more accurately monitor turnover and displacement of cells within the mammalian corneal epithelium. Collating information on the basic biology of SCs will have clinical ramifications in furthering our knowledge of the processes that govern their role in homeostasis, wound-healing, transplantation, and how we can improve current unsatisfactory SC-based therapies for patients suffering blinding corneal disease. PMID:26774909

  1. Fate of 4-nonylphenol and 17β-estradiol in the Redwood River of Minnesota

    Science.gov (United States)

    Writer, Jeffrey; Ryan, Joseph N.; Keefe, Steffanie H.; Barber, Larry B.

    2012-01-01

    The majority of previous research investigating the fate of endocrine-disrupting compounds has focused on single processes generally in controlled laboratory experiments, and limited studies have directly evaluated their fate and transport in rivers. This study evaluated the fate and transport of 4-nonylphenol, 17β-estradiol, and estrone in a 10-km reach of the Redwood River in southwestern Minnesota. The same parcel of water was sampled as it moved downstream, integrating chemical transformation and hydrologic processes. The conservative tracer bromide was used to track the parcel of water being sampled, and the change in mass of the target compounds relative to bromide was determined at two locations downstream from a wastewater treatment plant effluent outfall. In-stream attenuation coefficients (kstream) were calculated by assuming first-order kinetics (negative values correspond to attenuation, whereas positive values indicate production). Attenuation of 17β-estradiol (kstream = −3.2 ± 1.0 day–1) was attributed primarily due to sorption and biodegradation by the stream biofilm and bed sediments. Estrone (kstream = 0.6 ± 0.8 day–1) and 4-nonylphenol (kstream = 1.4 ± 1.9 day–1) were produced in the evaluated 10-km reach, likely due to biochemical transformation from parent compounds (17β-estradiol, 4-nonylphenolpolyethoxylates, and 4-nonyphenolpolyethoxycarboxylates). Despite attenuation, these compounds were transported kilometers downstream, and thus additive concentrations from multiple sources and transformation of parent compounds into degradates having estrogenic activity can explain their environmental persistence and widespread observations of biological disruption in surface waters.

  2. Water transport across biological membranes: Overton, water channels, and peritoneal dialysis.

    Science.gov (United States)

    Devuyst, O

    2010-01-01

    Peritoneal dialysis involves diffusive and convective transports and osmosis through the highly vascularized peritoneal membrane. Several lines of evidence have demonstrated that the water channel aquaporin-1 (AQP1) corresponds to the ultrasmall pore predicted by the modelization of peritoneal transport. Proof-of-principle studies have shown that upregulation of the expression of AQP1 in peritoneal capillaries is reflected by increased water permeability and ultrafiltration, without affecting the osmotic gradient and the permeability for small solutes. Inversely, studies in Aqp1 mice have shown that haplo-insufficiency in AQP1 is reflected by significant attenuation of water transport. Recent studies have identified lead compounds that could act as agonists of aquaporins, as well as putative binding sites and potential mechanisms of gating the water channel. By modulating water transport, these pharmacological agents could have clinically relevant effects in targeting specific tissues or disease states. These studies on the peritoneal membrane also provide an experimental framework to investigate the role of water channels in the endothelium and various cell types.

  3. Simulation of a relativistic heavy ions beam transport in the matter: contribution of the fragmentation process and biological implications

    International Nuclear Information System (INIS)

    The study of relativistic heavy ion collisions permit an approach of the properties of dense and not hadronic matter, and an analysis of the reaction mechanisms. Such studies are also interesting on the biological point of view, since there exist now well defined projects concerning the radiotherapy with high LET particles as neutrons, protons, heavy ions. It is thus necessary to have a good understanding of the processes which occur in the propagation of a relativistic heavy ion beam (E≥ 100 A.MeV) in matter. We have elaborated a three dimensional transport code, using a Monte Carlo method, in order to describe the propagation of Ne and Ar ions in water. Violent nuclear collisions giving fragmentation process have been taken into account by use of the FREESCO program. We have tested the validity of our transport model and we show an important change of the energy deposition at the vicinity of the Bragg peak; such a distortion, due mainly to fragmentation reactions, is of a great interest for biological applications. (author)

  4. Simultaneous transport of two bacterial strains in intact cores from Oyster, Virginia: biological effects and numerical modeling.

    Science.gov (United States)

    Dong, Hailiang; Rothmel, Randi; Onstott, Tullis C; Fuller, Mark E; DeFlaun, Mary F; Streger, Sheryl H; Dunlap, Robb; Fletcher, Madilyn

    2002-05-01

    The transport characteristics of two adhesion-deficient, indigenous groundwater strains, Comamonas sp. strain DA001 and Erwinia herbicola OYS2-A, were studied by using intact sediment cores (7 by 50 cm) from Oyster, Va. Both strains are gram-negative rods (1.10 by 0.56 and 1.56 by 0.46 microm, respectively) with strongly hydrophilic membranes and a slightly negative surface charge. The two strains exhibited markedly different behaviors when they were transported through granular porous sediment. To eliminate any effects of physical and chemical heterogeneity on bacterial transport and thus isolate the biological effect, the two strains were simultaneously injected into the same core. DA001 cells were metabolically labeled with (35)S and tagged with a vital fluorescent stain, while OYS2-A cells were metabolically labeled with (14)C. The fast decay of (35)S allowed deconvolution of the two isotopes (and therefore the two strains). Dramatic differences in the transport behaviors were observed. The breakthrough of DA001 and the breakthrough of OYS2-A both occurred before the breakthrough of a conservative tracer (termed differential advection), with effluent recoveries of 55 and 30%, respectively. The retained bacterial concentration of OYS2-A in the sediment was twofold higher than that of DA001. Among the cell properties analyzed, the statistically significant differences between the two strains were cell length and diameter. The shorter, larger-diameter DA001 cells displayed a higher effluent recovery than the longer, smaller-diameter OYS2-A cells. CXTFIT modeling results indicated that compared to the DA001 cells, the OYS2-A cells experienced lower pore velocity, higher porosity, a higher attachment rate, and a lower detachment rate. All these factors may contribute to the observed differences in transport. PMID:11976080

  5. Determination of biological transport of oxygen-15 and carbon-11 generated in rats

    International Nuclear Information System (INIS)

    The distribution of induced 15O and 11C activity in live and dead rats was determined following local irradiation with a 32 MeV proton beam. Results indicate that rapid biological redistribution of some of the induced activity occurs within a minute following irradiation. Sufficient activity remains, bound in the intracellular water, to define the proton beam in tissue. Thus, mapping of the induced 15O activity proves to be a valid means of beam localization

  6. The international transportation of zoo animals: conserving biological diversity and protecting animal welfare

    OpenAIRE

    Peter Linhart†; Adams, David B.; Thomas Voracek

    2008-01-01

    Issues pertaining to the long distance transportation of animals are examined according to the aspirations of the world’s zoo community. Guidance comes from the World Association of Zoos and Aquariums (WAZA), the civil society organisation that provides ‘leadership and support for zoos, aquariums and partner organisations of the world in animal care and welfare, conservation of biodiversity, environmental education and global sustainability’. The authors describe why it is necessary to transp...

  7. Preparation, characterization, biological activity, and transport study of polystyrene based calcium–barium phosphate composite membrane

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Mohammad Mujahid Ali; Rafiuddin,, E-mail: rafi_amu@rediffmail.com

    2013-10-15

    Calcium–barium phosphate (CBP) composite membrane with 25% polystyrene was prepared by co-precipitation method. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transformed infrared (FTIR), and Thermogravimetric analysis (TGA) were used to characterize the membrane. The membrane was found to be crystalline in nature with consistent arrangement of particles and no indication of visible cracks. The electrical potentials measured across the composite membrane in contact with univalent electrolytes (KCl, NaCl and LiCl), have been found to increase with decrease in concentrations. Thus the membrane was found to be cation-selective. Transport properties of developed membranes may be utilized for the efficient desalination of saline water and more importantly demineralization process. The antibacterial study of this composite membrane shows good results for killing the disease causing bacteria along with waste water treatment. Highlights: • Transport properties of composite membrane are evaluated. • The composite membrane was found to be stable in all media. • TMS method is used for electrochemical characterization. • The membrane was found to be cation selective. • The order of surface charge density was found to be LiCl < NaCl < KCl.

  8. Ecological fate and effects of solvent-refined-coal (SRC) materials: a status report

    Energy Technology Data Exchange (ETDEWEB)

    Strand, J.A. III; Vaughan, B.E. (eds.)

    1981-10-01

    Non-occupational health effects associated with SRC operation will be determined by environmental factors governing the form, transport, and persistence of SRC materials and wastes - factors which also mediate exposure to man. Accordingly, the research described is an attempt to determine the fate of disposed solid wastes and spilled SRC materials, and it necessarily focuses on water soluble, persistent materials with greatest potential for mobility and incorporation into water and food supplies. Initially, aqueous equilibrations of SRC-II liquid material and SRC-I nongasified mineral residue were subjected to chemical characterization. Subsequently, laboratory studies were performed on the interaction of aqueous equilibrates of SRC-II liquid and SRC-I non-gasified mineral residue with soil materials isolated suspended sediments, and bottom sediments. These studies were designed to identify effects of specific sorption reactions ion or induced-ion exchange reactions, and toxicity of water soluble, biologically active materials derived from liquid and solid wastes. Results of these experiments have applicability to the environmental fate and effects of biologically active compounds released under different scenarios from product spills and solid waste disposal.

  9. Combined ion conductance and fluorescence confocal microscopy for biological cell membrane transport studies

    Science.gov (United States)

    Shevchuk, A. I.; Novak, P.; Velazquez, M. A.; Fleming, T. P.; Korchev, Y. E.

    2013-09-01

    Optical visualization of nanoscale morphological changes taking place in living biological cells during such important processes as endo- and exocytosis is challenging due to the low refractive index of lipid membranes. In this paper we summarize and discuss advances in the powerful combination of two complementary live imaging techniques, ion conductance and fluorescence confocal microscopy, that allows cell membrane topography to be related with molecular-specific fluorescence at high spatial and temporal resolution. We demonstrate the feasibility of the use of ion conductance microscopy to image apical plasma membrane of mouse embryo trophoblast outgrowth cells at a resolution sufficient to depict single endocytic pits. This opens the possibility to study individual endocytic events in embryo trophoblast outgrowth cells where endocytosis plays a crucial role during early stages of embryo development.

  10. Choice of pesticide fate models

    International Nuclear Information System (INIS)

    The choice of a pesticide fate model at field scale is linked to the available input data. The article describes the available pesticide fate models at a field scale and the guidelines for the choice of the suitable model as function of the data input requested

  11. Phylogenesis and Biological Characterization of a New Glucose Transporter in the Chicken (Gallus gallus, GLUT12.

    Directory of Open Access Journals (Sweden)

    Edouard Coudert

    Full Text Available In mammals, insulin-sensitive GLUTs, including GLUT4, are recruited to the plasma membrane of adipose and muscle tissues in response to insulin. The GLUT4 gene is absent from the chicken genome, and no functional insulin-sensitive GLUTs have been characterized in chicken tissues to date. A nucleotide sequence is predicted to encode a chicken GLUT12 ortholog and, interestingly, GLUT12 has been described to act as an insulin-sensitive GLUT in mammals. It encodes a 596 amino acid protein exhibiting 71% identity with human GLUT12. First, we present the results of a phylogenetic study showing the stability of this gene during evolution of vertebrates. Second, tissue distribution of chicken SLC2A12 mRNA was characterized by RT-PCR. It was predominantly expressed in skeletal muscle and heart. Protein distribution was analysed by Western blotting using an anti-human GLUT12 antibody directed against a highly conserved region (87% of identity. An immuno-reactive band of the expected size (75kDa was detected in the same tissues. Third a physiological characterization was performed: SLC2A12 mRNA levels were significantly lowered in fed chickens subjected to insulin immuno-neutralization. Finally, recruitment of immuno-reactive GLUT12 to the muscle plasma membrane was increased following 1h of intraperitoneal insulin administration (compared to a control fasted state. Thus insulin administration elicited membrane GLUT12 recruitment. In conclusion, these results suggest that the facilitative glucose transporter protein GLUT12 could act in chicken muscle as an insulin-sensitive transporter that is qualitatively similar to GLUT4 in mammals.

  12. Phylogenesis and Biological Characterization of a New Glucose Transporter in the Chicken (Gallus gallus), GLUT12.

    Science.gov (United States)

    Coudert, Edouard; Pascal, Géraldine; Dupont, Joëlle; Simon, Jean; Cailleau-Audouin, Estelle; Crochet, Sabine; Duclos, Michel Jacques; Tesseraud, Sophie; Métayer-Coustard, Sonia

    2015-01-01

    In mammals, insulin-sensitive GLUTs, including GLUT4, are recruited to the plasma membrane of adipose and muscle tissues in response to insulin. The GLUT4 gene is absent from the chicken genome, and no functional insulin-sensitive GLUTs have been characterized in chicken tissues to date. A nucleotide sequence is predicted to encode a chicken GLUT12 ortholog and, interestingly, GLUT12 has been described to act as an insulin-sensitive GLUT in mammals. It encodes a 596 amino acid protein exhibiting 71% identity with human GLUT12. First, we present the results of a phylogenetic study showing the stability of this gene during evolution of vertebrates. Second, tissue distribution of chicken SLC2A12 mRNA was characterized by RT-PCR. It was predominantly expressed in skeletal muscle and heart. Protein distribution was analysed by Western blotting using an anti-human GLUT12 antibody directed against a highly conserved region (87% of identity). An immuno-reactive band of the expected size (75kDa) was detected in the same tissues. Third a physiological characterization was performed: SLC2A12 mRNA levels were significantly lowered in fed chickens subjected to insulin immuno-neutralization. Finally, recruitment of immuno-reactive GLUT12 to the muscle plasma membrane was increased following 1h of intraperitoneal insulin administration (compared to a control fasted state). Thus insulin administration elicited membrane GLUT12 recruitment. In conclusion, these results suggest that the facilitative glucose transporter protein GLUT12 could act in chicken muscle as an insulin-sensitive transporter that is qualitatively similar to GLUT4 in mammals.

  13. Transport behavior of surrogate biological warfare agents in a simulated landfill: Effect of leachate recirculation and water infiltration

    KAUST Repository

    Saikaly, Pascal

    2010-11-15

    An understanding of the transport behavior of biological warfare (BW) agents in landfills is required to evaluate the suitability of landfills for the disposal of building decontamination residue (BDR) following a bioterrorist attack on a building. Surrogate BW agents, Bacillus atrophaeus spores and Serratia marcescens, were spiked into simulated landfill reactors that were filled with synthetic building debris (SBD) and operated for 4 months with leachate recirculation or water infiltration. Quantitative polymerase chain reaction (Q-PCR) was used to monitor surrogate transport. In the leachate recirculation reactors, <10% of spiked surrogates were eluted in leachate over 4 months. In contrast, 45% and 31% of spiked S. marcescens and B. atrophaeus spores were eluted in leachate in the water infiltration reactors. At the termination of the experiment, the number of retained cells and spores in SBD was measured over the depth of the reactor. Less than 3% of the total spiked S. marcescens cells and no B. atrophaeus spores were detected in SBD. These results suggest that significant fractions of the spiked surrogates were strongly attached to SBD. © 2010 American Chemical Society.

  14. An evaluation of mathematical models of the transport of biologically reacting solutes in saturated soils and aquifers

    Science.gov (United States)

    Baveye, Philippe; Valocchi, Albert

    1989-06-01

    Three different conceptual frameworks have been adopted in the past for the development of mathematical models of bacterial growth and biologically reacting solute transport in saturated porous media. Two schools of thought are based upon assuming that the pore scale geometrical configuration of the attached bacteria consists of biofilms or microcolonies; the third school of thought represents the traditional approach where pore scale processes are neglected and the bacteria are assumed to respond to the macroscopic bulk fluid substrate concentration. On the basis of a schematic block diagram representation of a saturated porous medium hosting a microbial population, it is shown that these frameworks share a common theoretical foundation, and that they differ only by the choice of particular constitutive equations for several transfer parameters. Using one possible option in this respect, we derive a mathematical model that involves no unwarranted assumption about the distribution of the microorganisms in the pore space. The governing equations of this latter model are shown to be formally identical to those obtained by F.J. Molz et al. (1986), using the concept of microcolony, and to those that would result from adopting a simple form of biofilm model to describe bacterial growth in the pore space. Some of the consequences of this formal similarity between macroscopic transport equations obtained in different conceptual frameworks are discussed from an operational standpoint and in terms of model validation.

  15. FOB-SH: Fragment orbital-based surface hopping for charge carrier transport in organic and biological molecules and materials

    Science.gov (United States)

    Spencer, J.; Gajdos, F.; Blumberger, J.

    2016-08-01

    We introduce a fragment orbital-based fewest switches surface hopping method, FOB-SH, designed to efficiently simulate charge carrier transport in strongly fluctuating condensed phase systems such as organic semiconductors and biomolecules. The charge carrier wavefunction is expanded and the electronic Hamiltonian constructed in a set of singly occupied molecular orbitals of the molecular sites that mediate the charge transfer. Diagonal elements of the electronic Hamiltonian (site energies) are obtained from a force field, whereas the off-diagonal or electronic coupling matrix elements are obtained using our recently developed analytic overlap method. We derive a general expression for the exact forces on the adiabatic ground and excited electronic state surfaces from the nuclear gradients of the charge localized electronic states. Applications to electron hole transfer in a model ethylene dimer and through a chain of ten model ethylenes validate our implementation and demonstrate its computational efficiency. On the larger system, we calculate the qualitative behaviour of charge mobility with change in temperature T for different regimes of the intermolecular electronic coupling. For small couplings, FOB-SH predicts a crossover from a thermally activated regime at low temperatures to a band-like transport regime at higher temperatures. For higher electronic couplings, the thermally activated regime disappears and the mobility decreases according to a power law. This is interpreted by a gradual loss in probability for resonance between the sites as the temperature increases. The polaron hopping model solved for the same system gives a qualitatively different result and underestimates the mobility decay at higher temperatures. Taken together, the FOB-SH methodology introduced here shows promise for a realistic investigation of charge carrier transport in complex organic, aqueous, and biological systems.

  16. BROMOC suite: Monte Carlo/Brownian dynamics suite for studies of ion permeation and DNA transport in biological and artificial pores with effective potentials.

    Science.gov (United States)

    De Biase, Pablo M; Markosyan, Suren; Noskov, Sergei

    2015-02-01

    The transport of ions and solutes by biological pores is central for cellular processes and has a variety of applications in modern biotechnology. The time scale involved in the polymer transport across a nanopore is beyond the accessibility of conventional MD simulations. Moreover, experimental studies lack sufficient resolution to provide details on the molecular underpinning of the transport mechanisms. BROMOC, the code presented herein, performs Brownian dynamics simulations, both serial and parallel, up to several milliseconds long. BROMOC can be used to model large biological systems. IMC-MACRO software allows for the development of effective potentials for solute-ion interactions based on radial distribution function from all-atom MD. BROMOC Suite also provides a versatile set of tools to do a wide variety of preprocessing and postsimulation analysis. We illustrate a potential application with ion and ssDNA transport in MspA nanopore. PMID:25503688

  17. Quantifying intrinsic and extrinsic control of single-cell fates in cancer and stem/progenitor cell pedigrees with competing risks analysis

    OpenAIRE

    J. A. Cornwell; Hallett, R. M.; S. Auf der Mauer; A. Motazedian; Schroeder, T.; J. S. Draper; Harvey, R. P.; R. E. Nordon

    2016-01-01

    The molecular control of cell fate and behaviour is a central theme in biology. Inherent heterogeneity within cell populations requires that control of cell fate is studied at the single-cell level. Time-lapse imaging and single-cell tracking are powerful technologies for acquiring cell lifetime data, allowing quantification of how cell-intrinsic and extrinsic factors control single-cell fates over time. However, cell lifetime data contain complex features. Competing cell fates, censoring, an...

  18. Understanding the transport of Patagonian dust and its influence on marine biological activity in the South Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    M. S. Johnson

    2011-03-01

    Full Text Available The supply of bioavailable iron to the high-nitrate low-chlorophyll (HNLC waters of the Southern Ocean through atmospheric pathways could stimulate phytoplankton blooms and have major implications for the global carbon cycle. In this study, model results and remotely-sensed data are analyzed to examine the horizontal and vertical transport pathways of Patagonian dust and quantify the effect of iron-laden mineral dust deposition on marine biological productivity in the surface waters of the South Atlantic Ocean (SAO. Model simulations for the atmospheric transport and deposition of mineral dust and bioavailable iron are carried out for two large dust outbreaks originated at the source regions of northern Patagonia during the austral summer of 2009. Model-simulated horizontal and vertical transport pathways of Patagonian dust plumes are in reasonable agreement with remotely-sensed data. Simulations indicate that the synoptic meteorological patterns of high and low pressure systems are largely accountable for dust transport trajectories over the SAO. According to model results and retrievals from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO, synoptic flows caused by opposing pressure systems (a high pressure system located to the east or north-east of a low pressure system elevate the South American dust plumes well above the marine boundary layer. Under such conditions, the bulk concentration of mineral dust can quickly be transported around the low pressure system in a clockwise manner, follow the southeasterly advection pathway, and reach the HNLC waters of the SAO and Antarctica in ~3–4 days after emission from the source regions of northern Patagonia. Two different mechanisms for dust-iron mobilization into a bioavailable form are considered in this study. A global 3-D chemical transport model (GEOS-Chem, implemented with an iron dissolution scheme, is employed to estimate the atmospheric fluxes of soluble

  19. Understanding the transport of Patagonian dust and its influence on marine biological activity in the South Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    M. S. Johnson

    2010-11-01

    Full Text Available The supply of bioavailable iron to the high-nitrate low-chlorophyll (HNLC waters of the Southern Ocean through atmospheric pathways could stimulate phytoplankton blooms and have major implications for the global carbon cycle. In this study, model results and remotely-sensed data are analyzed to examine the horizontal and vertical transport pathways of Patagonian dust and quantify the effect of iron-laden mineral dust deposition on marine biological productivity in the surface waters of the South Atlantic Ocean (SAO. Model simulations for the atmospheric transport and deposition of mineral dust and bioavailable iron are carried out for two large dust outbreaks originated at the source regions of Northern Patagonia during the austral summer of 2009. Model-simulated horizontal and vertical transport pathways of Patagonian dust plumes are in reasonable agreement with remotely-sensed data. Simulations indicate that the synoptic meteorological patterns of high and low pressure systems are largely accountable for dust transport trajectories over the SAO. According to model results and retrievals from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO, synoptic flows caused by opposing pressure systems (a high pressure system located to the east or north-east of a low pressure system elevate the South American dust plumes well above the marine boundary layer. Under such conditions, the bulk concentration of mineral dust can quickly be transported around the low pressure system in a clockwise manner, follow the southeasterly advection pathway, and reach the HNLC waters of the SAO and Antarctica in ~3–4 days after emission from the source regions of Northern Patagonia. Two different mechanisms for dust-iron mobilization into a bioavailable form are considered in this study. A global 3-D chemical transport model (GEOS-Chem, implemented with an iron dissolution scheme, is employed to estimate the atmospheric fluxes of soluble

  20. Wood retention and transport in tropical, headwater streams, La Selva Biological Station, Costa Rica

    Science.gov (United States)

    Cadol, Daniel; Wohl, Ellen

    2010-11-01

    Wood in tropical streams has the potential to be more mobile than wood in otherwise similar temperate streams because of the warm and humid conditions that promote decay and the more frequent and flashier floods of the tropics. To test this hypothesis, we monitored all large wood pieces for 2.3 years in 10 50-m-long reaches of old-growth headwater streams in La Selva Biological Station, Costa Rica. Annual wood retention rates for pieces ranged from 0.55 to 0.91 among the sites, and retention rates by volume ranged from 0.67 to 0.99. Assuming steady state wood load, which is reasonable for La Selva, these rates are equivalent to mean residence times of 2.2-10.6 years for pieces, and 3.0-83.2 years for a volume of wood. Calculating mean residence time from the weighted average of retention rates gives an average residence time of 4.9 years for a piece of wood and 6.9 years for a volume of wood. These values are less than those reported for old-growth temperate forests, supporting our hypothesis. Mobility of individual pieces was best predicted by piece length relative to stream width ( lr, higher lr led to lower mobility), channel gradient ( s, higher s led to higher mobility), and piece integration into the channel (unattached pieces were 2.6 times more mobile than attached, ramp, or bridge pieces). Temporal variation in retention rates was well explained by variation in peak flow. All four of these factors have also been observed to influence mobility in the temperate zone. The higher mobility of wood in our study site relative to the temperate rainforest of the Pacific Northwest may be explained by the flashy and frequent floods, the high decay rate, or the branching morphology of the native trees; but differentiating the role of these factors, particularly flow and decay, will be complicated by their covariation across climates.

  1. Formation and fate of marine snow : small-scale processes with large-scale implications

    DEFF Research Database (Denmark)

    Kiørboe, Thomas

    2001-01-01

    Marine snow aggregates are believed to be the main vehicles for vertical material transport in the ocean. However, aggregates are also sites of elevated heterotrophic activity, which may rather cause enhanced retention of aggregated material in the upper ocean. Small-scale biological-physical...... to the aggregate. Also, suspended bacteria may enjoy the elevated concentration of organic solutes in the plume. I explore these small-scale formation and degradation processes by means of models, experiments and field observations. The larger scale implications for the structure and functioning of pelagic food...... interactions govern the formation and fate of marine snow. Aggregates may form by physical coagulation: fluid motion causes collisions between small primary particles (e.g. phytoplankton) that may then stick together to form aggregates with enhanced sinking velocities. Bacteria may subsequently solubilise...

  2. Reconstruction of complex passageways for simulations of transport phenomena: development of a graphical user interface for biological applications.

    Science.gov (United States)

    Godo, M N; Morgan, K T; Richardson, R B; Kimbell, J S

    1995-07-01

    Flow of fluids, such as blood, lymph and air, plays a major role in the normal physiology of all living organisms. Within individual organ systems, flow fields may significantly influence the transport of solutes, including nutrients and chemical toxicants, to and from the confining vessel walls (epithelia and endothelia). Computational fluid dynamics (CFD) provides a potentially useful tool for biologists and toxicologists investigating solute disposition in these flow fields in both normal and disease states. Application of CFD is dependent upon generation of accurate representations of the geometry of the system of interest in the form of a computational reconstruction. The present investigations, which were based on studies of the toxicology of inhaled reactive gases in the respiratory tract of rodents, provide computer programs for the generation of finite element meshes from serial tissue cross-sections. These programs, which interface with a commercial finite element fluid dynamics simulation package (FIDAP 7.05, Fluid Dynamics International, Evanston, IL), permit simulation of fluid flow in the complex geometries and local solute mass flux to the vessel walls of biological systems. The use of these programs and their application to studies of respiratory tract toxicology are described.

  3. Wind forcing and fate of Sardinella aurita eggs and larvae in the Sicily Channel (Mediterranean Sea)

    Science.gov (United States)

    Torri, M.; Corrado, R.; Falcini, F.; Cuttitta, A.; Palatella, L.; Lacorata, G.; Patti, B.; Arculeo, M.; Mazzola, S.; Santoleri, R.

    2015-09-01

    Multidisciplinary studies are recently seeking to define diagnostic tools for fishery sustainability by coupling ichthyoplanktonic datasets, physical and bio-geochemical oceanographic measurements, and ocean modelling. The main goal of these efforts is the understanding of those processes that control fate and dispersion of fish larvae and eggs and thus tune the inter-annual variability of biomass of fish species. We here analyzed eggs and larvae distribution and biological features of Sardinella aurita in the northeast sector of the Sicily Channel (Mediterranean Sea) collected during the 2010 and 2011 summer cruises. We make use of satellite sea surface temperature, wind, and chlorophyll data to recognize the main oceanographic patterns that mark eggs and larvae transport processes and we pair these data with Lagrangian runs. To provide a physical explanation of the transport processes that we observe, we hire a potential vorticity (PV) model that takes into account the role of wind stress in generating those cold filaments responsible for the offshore delivery of eggs and larvae. Our results show that the strong offshore transport towards Malta occurring in 2010 is related to a persistent wind forcing along the southern Sicilian coast that generated an observable cold filament. Such a pattern is not found in the 2011 analysis, which indeed shows a more favorable condition for sardinella larvae recruiting with a weak offshore transport. Our results want to add some insights regarding operational oceanography for sustainable fishery.

  4. The Atmospheric Fate of Organic Nitrogen Compounds

    Science.gov (United States)

    Borduas, Nadine

    Organic nitrogen compounds are present in our atmosphere from biogenic and anthropogenic sources and have impacts on air quality and climate. Due to recent advances in instrumentation, these compounds are being detected in the gas and particle phases, raising questions as to their source, processing and sinks in the environment. With their recently identified role as contributors to aerosol formation and growth, their novel large scale use as solvents in carbon capture and storage (CCS) technology and their emissions from cigarette smoke, it is now important to address the gaps in our understanding of the fate of organic nitrogen. Experimentally and theoretically, I studied the chemical atmospheric fate of specific organic nitrogen compounds in the amine, amide and isocyanate families, yielding information that can be used in chemical transport models to assess the fate of this emerging class of atmospheric molecules. I performed kinetic laboratory studies in a smog chamber to measure the room temperature rate coefficient for reaction with the hydroxyl radical of monoethanolamine, nicotine, and five different amides. I employed online-mass spectrometry techniques to quantify the oxidation products. I found that amines react quickly with OH radicals with lifetimes of a few hours under sunlit conditions, producing amides as oxidation products. My studies on amides revealed that they have much longer lifetimes in the atmosphere, ranging from a few hours to a week. Photo-oxidation of amides produces isocyanates and I investigated these mechanisms in detail using ab initio calculations. Furthermore, I experimentally measured isocyanic acid's Henry's Law constant as well as its hydrolysis rate constants to better understand its sinks in the atmosphere. Finally, I re-examined the structure-activity relationship (SAR) of organic nitrogen molecules for improved model parameterizations.

  5. Fate of Pharmaceuticals and Personal Care Products (PPCPs) in Saturated Soil Under Various Redox Conditions

    Science.gov (United States)

    Dror, I.; Menahem, A.; Berkowitz, B.

    2014-12-01

    The growing use of PPCPs results in their increasing release to the aquatic environment. Consequently, understanding the fate of PPCPs under environmentally relevant conditions that account for dynamic flow and varying redox states is critical. In this study, the transport of two organometallic PPCPs, Gd-DTPA and Roxarsone (As complex) and their metal salts (Gd(NO3)3, AsNaO2), is investigated. The former is used widely as a contrasting agent for MRI, while the latter is applied extensively as a food additive in the broiler poultry industry. Both of these compounds are excreted from the body, almost unchanged chemically. Gadolinium complexes are not fully eliminated in wastewater treatment and can reach groundwater via irrigation with treated wastewater; Roxarsone can enter groundwater via leaching from manure used as fertilizer. Studies have shown that the transport of PPCPs in groundwater is affected by environmental conditions such as redox states, pH, and soil type. For this study, column experiments using sand or Mediterranean red sandy clay soil were performed under several redox conditions: aerobic, nitrate-reducing, iron-reducing, sulfate-reducing, methanogenic, and very strongly chemical reducing. Batch experiments to determine adsorption isotherms were also performed for the complexes and metal salts. We found that Gd-DTPA transport was affected by the soil type and was not affected by the redox conditions. In contrast, Roxarsone transport was affected mainly by the different redox conditions, showing delayed breakthrough curves as the conditions became more biologically reduced (strong chemical reducing conditions did not affect the transport). We also observed that the metal salts show essentially no transport while the organic complexes display much faster breakthrough. The results suggest that transport of these PPCPs through soil and groundwater is determined by the redox conditions, as well as by soil type and the form of the applied metal (as salt

  6. Cell fate regulation in early mammalian development

    Science.gov (United States)

    Oron, Efrat; Ivanova, Natalia

    2012-08-01

    Preimplantation development in mammals encompasses a period from fertilization to implantation and results in formation of a blastocyst composed of three distinct cell lineages: epiblast, trophectoderm and primitive endoderm. The epiblast gives rise to the organism, while the trophectoderm and the primitive endoderm contribute to extraembryonic tissues that support embryo development after implantation. In many vertebrates, such as frog or fish, maternally supplied lineage determinants are partitioned within the egg. Cell cleavage that follows fertilization results in polarization of these factors between the individual blastomeres, which become restricted in their developmental fate. In contrast, the mouse oocyte and zygote lack clear polarity and, until the eight-cell stage, individual blastomeres retain the potential to form all lineages. How are cell lineages specified in the absence of a maternally supplied blueprint? This is a fundamental question in the field of developmental biology. The answer to this question lies in understanding the cell-cell interactions and gene networks involved in embryonic development prior to implantation and using this knowledge to create testable models of the developmental processes that govern cell fates. We provide an overview of classic and contemporary models of early lineage development in the mouse and discuss the emerging body of work that highlights similarities and differences between blastocyst development in the mouse and other mammalian species.

  7. A GAMOS plug-in for GEANT4 based Monte Carlo simulation of radiation-induced light transport in biological media

    OpenAIRE

    Glaser, Adam K.; Kanick, Stephen C.; Zhang, Rongxiao; Arce, Pedro; Pogue, Brian W.

    2013-01-01

    We describe a tissue optics plug-in that interfaces with the GEANT4/GAMOS Monte Carlo (MC) architecture, providing a means of simulating radiation-induced light transport in biological media for the first time. Specifically, we focus on the simulation of light transport due to the Čerenkov effect (light emission from charged particle’s traveling faster than the local speed of light in a given medium), a phenomenon which requires accurate modeling of both the high energy particle and subsequen...

  8. Mass Transport within Soils

    Energy Technology Data Exchange (ETDEWEB)

    McKone, Thomas E.

    2009-03-01

    zone with three major horizons, the saturated zone can be further divided into other zones based on hydraulic and geologic conditions. Wetland soils are a special and important class in which near-saturation conditions exist most of the time. When a contaminant is added to or formed in a soil column, there are several mechanisms by which it can be dispersed, transported out of the soil column to other parts of the environment, destroyed, or transformed into some other species. Thus, to evaluate or manage any contaminant introduced to the soil column, one must determine whether and how that substance will (1) remain or accumulate within the soil column, (2) be transported by dispersion or advection within the soil column, (3) be physically, chemically, or biologically transformed within the soil (i.e., by hydrolysis, oxidation, etc.), or (4) be transported out of the soil column to another part of the environment through a cross-media transfer (i.e., volatilization, runoff, ground water infiltration, etc.). These competing processes impact the fate of physical, chemical, or biological contaminants found in soils. In order to capture these mechanisms in mass transfer models, we must develop mass-transfer coefficients (MTCs) specific to soil layers. That is the goal of this chapter. The reader is referred to other chapters in this Handbook that address related transport processes, namely Chapter 13 on bioturbation, Chapter 15 on transport in near-surface geological formations, and Chapter 17 on soil resuspention. This chapter addresses the following issues: the nature of soil pollution, composition of soil, transport processes and transport parameters in soil, transformation processes in soil, mass-balance models, and MTCs in soils. We show that to address vertical heterogeneity in soils in is necessary to define a characteristic scaling depth and use this to establish process-based expressions for soil MTCs. The scaling depth in soil and the corresponding MTCs depend

  9. Lower biological efficacy of 90Y-loaded glass microspheres results from microspheres transport in the arterial hepatic tree

    International Nuclear Information System (INIS)

    centred around 103 Gy (FWHM = 20 Gy). In the last simulation the dose distribution became significantly asymmetric with a shift of the maximum from 103 Gy to 30 Gy and about 35% of lobules got a dose lower than 40 Gy for the hepatocytes, the central vein and the portal tracts. Conclusions: the larger microspheres non-uniform trapping produced by their transport in the arterial tree seems to explain the lower biological efficacy of the glass microspheres. (authors)

  10. Power-Law Modeling of Cancer Cell Fates Driven by Signaling Data to Reveal Drug Effects

    Science.gov (United States)

    Zhang, Fan; Wu, Min; Kwoh, Chee Keong; Zheng, Jie

    2016-01-01

    Extracellular signals are captured and transmitted by signaling proteins inside a cell. An important type of cellular responses to the signals is the cell fate decision, e.g., apoptosis. However, the underlying mechanisms of cell fate regulation are still unclear, thus comprehensive and detailed kinetic models are not yet available. Alternatively, data-driven models are promising to bridge signaling data with the phenotypic measurements of cell fates. The traditional linear model for data-driven modeling of signaling pathways has its limitations because it assumes that the a cell fate is proportional to the activities of signaling proteins, which is unlikely in the complex biological systems. Therefore, we propose a power-law model to relate the activities of all the measured signaling proteins to the probabilities of cell fates. In our experiments, we compared our nonlinear power-law model with the linear model on three cancer datasets with phosphoproteomics and cell fate measurements, which demonstrated that the nonlinear model has superior performance on cell fates prediction. By in silico simulation of virtual protein knock-down, the proposed model is able to reveal drug effects which can complement traditional approaches such as binding affinity analysis. Moreover, our model is able to capture cell line specific information to distinguish one cell line from another in cell fate prediction. Our results show that the power-law data-driven model is able to perform better in cell fate prediction and provide more insights into the signaling pathways for cancer cell fates than the linear model. PMID:27764199

  11. Development of Quantitative Real-Time PCR Assays for Detection and Quantification of Surrogate Biological Warfare Agents in Building Debris and Leachate▿

    OpenAIRE

    Pascal E. Saikaly; Barlaz, Morton A.; de los Reyes, Francis L.

    2007-01-01

    Evaluation of the fate and transport of biological warfare (BW) agents in landfills requires the development of specific and sensitive detection assays. The objective of the current study was to develop and validate SYBR green quantitative real-time PCR (Q-PCR) assays for the specific detection and quantification of surrogate BW agents in synthetic building debris (SBD) and leachate. Bacillus atrophaeus (vegetative cells and spores) and Serratia marcescens were used as surrogates for Bacillus...

  12. Assessment of contaminant fate in catchments using a novel integrated hydrobiogeochemical-multimedia fate model.

    Science.gov (United States)

    Nizzetto, Luca; Butterfield, Dan; Futter, Martyn; Lin, Yan; Allan, Ian; Larssen, Thorjørn

    2016-02-15

    Models for pollution exposure assessment typically adopt an overly simplistic representation of geography, climate and biogeochemical processes. This strategy is unsatisfactory when high temporal resolution simulations for sub-regional spatial domains are performed, in which parameters defining scenarios can vary interdependently in space and time. This is, for example, the case when assessing the influence of biogeochemical processing on contaminant fate. Here we present INCA-Contaminants, the Integrated Catchments model for Contaminants; a new model that simultaneously and realistically solves mass balances of water, carbon, sediments and contaminants in the soil-stream-sediment system of catchments and their river networks as a function of climate, land use/management and contaminant properties. When forced with realistic climate and contaminant input data, the model was able to predict polychlorinated biphenyls (PCBs) concentrations in multiple segments of a river network in a complex landscape. We analyzed model output sensitivity to a number of hydro-biogeochemical parameters. The rate of soil organic matter mineralization was the most sensitive parameter controlling PCBs levels in river water, supporting the hypothesis that organic matter turnover rates will influence re-mobilization of previously deposited PCBs which had accumulated in soil organic matrix. The model was also used to project the long term fate of PCB 101 under two climate scenarios. Catchment diffuse run-off and riverine transport were the major pathways of contaminant re-mobilization. Simulations show that during the next decade the investigated boreal catchment will shift from being a net atmospheric PCB sink to a net source for air and water, with future climate perturbation having little influence on this trend. Our results highlight the importance of using credible hydro-biogeochemical simulations when modeling the fate of hydrophobic contaminants. PMID:26674684

  13. Subsurface transport program: Research summary

    International Nuclear Information System (INIS)

    DOE's research program in subsurface transport is designed to provide a base of fundamental scientific information so that the geochemical, hydrological, and biological mechanisms that contribute to the transport and long term fate of energy related contaminants in subsurface ecosystems can be understood. Understanding the physical and chemical mechanisms that control the transport of single and co-contaminants is the underlying concern of the program. Particular attention is given to interdisciplinary research and to geosphere-biosphere interactions. The scientific results of the program will contribute to resolving Departmental questions related to the disposal of energy-producing and defense wastes. The background papers prepared in support of this document contain additional information on the relevance of the research in the long term to energy-producing technologies. Detailed scientific plans and other research documents are available for high priority research areas, for example, in subsurface transport of organic chemicals and mixtures and in the microbiology of deep aquifers. 5 figs., 1 tab

  14. Understanding the Transport of Patagonian Dust and Its Influence on Marine Biological Activity in the South Atlantic Ocean

    Science.gov (United States)

    Johnson, Matthew; Meskhidze, Nicholas; Kiliyanpilakkil, Praju; Gasso, Santiago

    2010-01-01

    Modeling and remote sensing techniques were applied to examine the horizontal and vertical transport pathways of Patagonian dust and quantify the effect of soluble-iron- laden mineral dust deposition on marine primary productivity in the South Atlantic Ocean (SAO) surface waters. The global chemistry transport model GEOS-Chem, implemented with an iron dissolution scheme, was applied to evaluate the atmospheric transport and deposition of mineral dust and bioavailable iron during two dust outbreaks originating in the source regions of Patagonia. In addition to this "rapidly released" iron, offline calculations were also carried out to estimate the amount of bioavailable iron leached during the residence time of dust in the ocean mixed layer. Model simulations showed that the horizontal and vertical transport pathways of Patagonian dust plumes were largely influenced by the synoptic meteorological patterns of high and low pressure systems. Model-predicted horizontal and vertical transport pathways of Patagonian dust over the SAO were in reasonable agreement with remotely-sensed data. Comparison between remotely-sensed and offline calculated ocean surface chlorophyll-a concentrations indicated that, for the two dust outbreaks examined in this study, the deposition of bioavailable iron in the SAO through atmospheric pathways was insignificant. As the two dust transport episodes examined here represent typical outflows of mineral dust from South American sources, our study suggests that the atmospheric deposition of mineral dust is unlikely to induce large scale marine primary productivity and carbon sequestration in the South Atlantic sector of the Southern Ocean.

  15. Chemicals as the Sole Transformers of Cell Fate

    Science.gov (United States)

    Ebrahimi, Behnam

    2016-01-01

    Forced expression of lineage-specific transcription factors in somatic cells can result in the generation of different cell types in a process named direct reprogramming, bypassing the pluripotent state. However, the introduction of transgenes limits the therapeutic applications of the produced cells. Numerous small-molecules have been introduced in the field of stem cell biology capable of governing self-renewal, reprogramming, transdifferentiation and regeneration. These chemical compounds are versatile tools for cell fate conversion toward desired outcomes. Cell fate conversion using small-molecules alone (chemical reprogramming) has superiority over arduous traditional genetic techniques in several aspects. For instance, rapid, transient, and reversible effects in activation and inhibition of functions of specific proteins are of the profits of small-molecules. They are cost-effective, have a long half-life, diversity on structure and function, and allow for temporal and flexible regulation of signaling pathways. Additionally, their effects could be adjusted by fine-tuning concentrations and combinations of different small-molecules. Therefore, chemicals are powerful tools in cell fate conversion and study of stem cell and chemical biology in vitro and in vivo. Moreover, transgene-free and chemical-only transdifferentiation approaches provide alternative strategies for the generation of various cell types, disease modeling, drug screening, and regenerative medicine. The current review gives an overview of the recent findings concerning transdifferentiation by only small-molecules without the use of transgenes. PMID:27426081

  16. The effect of biological shielding on fast neutron and photon transport in the VVER-1000 mock-up model placed in the LR-0 reactor.

    Science.gov (United States)

    Košťál, Michal; Cvachovec, František; Milčák, Ján; Mravec, Filip

    2013-05-01

    The paper is intended to show the effect of a biological shielding simulator on fast neutron and photon transport in its vicinity. The fast neutron and photon fluxes were measured by means of scintillation spectroscopy using a 45×45 mm(2) and a 10×10 mm(2) cylindrical stilbene detector. The neutron spectrum was measured in the range of 0.6-10 MeV and the photon spectrum in 0.2-9 MeV. The results of the experiment are compared with calculations. The calculations were performed with various nuclear data libraries.

  17. Peptide Transporter 1 : Biological Characteristics and Functions%小肽转运载体1的生物学特性及其功能

    Institute of Scientific and Technical Information of China (English)

    朱宇旌; 王秉玉; 张勇; 李欣蔚; 邵彩梅

    2012-01-01

    Intestinal peptide transporter 1 (PepTl) is a transporter of H + /peptide coupling, which has a function to transport dipeptide and tripeptide by proton gradient from the intestinal cavity to the intestinal cells. PepTl plays an important role in the regulation of free amino acids and polypeptide transportation in the intestine of animals. This paper reviewed the classification, biological characteristics and functions of PepTl, and the factors that regulate its activity. [Chinese Journal of Animal Nutrition, 2012 , 24(10) : 1847-1853]%小肽转运载体1(PepT1)是H+/肽偶联的转运载体.该载体通过利用肠腔到肠细胞的质子梯度来转运二肽和三肽.PepT1对游离氨基酸、多肽在动物肠道内的转运调控具有重要作用.本文综述了PepT1的分类、生物学特征及功能,并探讨了影响PepT1活性调控的因素.

  18. [Logistics of collection and transportation of biological samples and the organization of the central laboratory in the ELSA-Brasil].

    Science.gov (United States)

    Fedeli, Ligia G; Vidigal, Pedro G; Leite, Claudia Mendes; Castilhos, Cristina D; Pimentel, Robércia Anjos; Maniero, Viviane C; Mill, Jose Geraldo; Lotufo, Paulo A; Pereira, Alexandre C; Bensenor, Isabela M

    2013-06-01

    The ELSA (Estudo Longitudinal de Saúde do Adulto - Brazilian Longitudinal Study for Adult Health) is a multicenter cohort study which aims at the identification of risk factors associated with type 2 diabetes and cardiovascular diseases in the Brazilian population. The paper describes the strategies for the collection, processing, transportation, and quality control of blood and urine tests in the ELSA. The study decided to centralize the tests at one single laboratory. The processing of the samples was performed at the local laboratories, reducing the weight of the material to be transported, and diminishing the costs of transportation to the central laboratory at the Universidade de São Paulo Hospital. The study included tests for the evaluation of diabetes, insulin resistance, dyslipidemia, electrolyte abnormalities, thyroid hormones, uric acid, hepatic enzyme abnormalities, inflammation, and total blood cell count. In addition, leukocyte DNA, urine, plasma and serum samples were stored. The central laboratory performed approximately 375,000 tests.

  19. Effect of antisense transfecting of monocarboxylate transporter gene on biological characteristics of lung adenocarcinoma A549 cells

    Institute of Scientific and Technical Information of China (English)

    ZHANG Gui-zhi; HUANG Gui-jun; GUO Xian-jian; QIAN Gui-sheng

    2002-01-01

    Objective: To study the influence of transfecting antisense expression vector of the first subtype of the monocarboxylate transporter (MCT1) gene into lung cancer cells on pHi regulation, lactate transportation and cell growth, Methods: MCT1 antisense gene recombinant vector was introduced into human lung cancer cell line A549 by electroporation. The transfected A549 cells resistant to G418 were selected. Positive clones were examined by using PCR. The changes of intracellular pH and lactate were examined with spectrophotometric method. Cell growth was studied with cell growth curve. Results: Intracellular pH and lactate were remarkably decreased in the cells transfected pLXSN-MCT1 in comparison with A549 cells without transfection (P<0. 001). The growth of A549 cells transfected pLXSN-MCT1 was also inhibited remarkably. Conclusion: MCT1 gene may play an important role in pHi regulation, lactate transportation and cell growth in tumor cells.

  20. Meta-ecosystems and biological energy transport from ocean to coast: the ecological importance of herring migration.

    Science.gov (United States)

    Varpe, Oystein; Fiksen, Oyvind; Slotte, Aril

    2005-12-01

    Ecosystems are not closed, but receive resource subsidies from other ecosystems. Energy, material and organisms are moved between systems by physical vectors, but migrating animals also transport resources between systems. We report on large scale energy transport from ocean to coast by a migrating fish population, the Norwegian spring-spawning (NSS) herring Clupea harengus. We observe a rapid body mass increase during parts of the annual, oceanic feeding migration and we use a bioenergetics model to quantify energy consumption. The model predicts strong seasonal variation in food consumption with a marked peak in late May to July. The copepod Calanus finmarchicus is the most important prey and 23 x 10(6) tones (wet weight) of C. finmarchicus is consumed annually. The annual consumption-biomass ratio is 5.2. During the feeding migration 17% of consumed energy is converted to body mass. The biomass transported to the coast and left as reproductive output is estimated from gonad weight and is about 1.3 x 10(6) tones for the current population. This transport is to our knowledge the world's largest flux of energy caused by a single population. We demonstrate marked temporal variation in transport during the last century and discuss the effects of NSS herring in the ocean, as a major consumer, and at the coast, where eggs and larvae are important for coastal predators. In particular, we suggest that the rapid decline of lobster Homarus gammarus landings in Western Norway during the 1960s was related to the collapse of NSS herring. We also discuss spatial variation in energy transport caused by changed migration patterns. Both climate and fisheries probably triggered historical changes in the migration patterns of NSS herring. New migration routes emerge at the level of individuals, which in turn determines where resources are gathered and delivered, and therefore, how meta-ecosystems function. PMID:16195881

  1. Changes of biological functions of dipeptide transporter (PepT1)and hormonal regulation in severe scald rats

    Institute of Scientific and Technical Information of China (English)

    Bing-Wei Sun; Xiao-Chen Zhao; Guang-Ji Wang; Ning Li; Jie-Shou Li

    2003-01-01

    AIM: To determine the regulatory effects of recombinant human growth hormone (rhGH) on dipeptide transport (PepT1) in normal and severe scald rats.METHODS: Male Sprague-Dawley rats with 30 % total body surface area (TBSA) Ⅲ degree scald were employed as the model. In this study rhGH was used at the dose of 2 IU.kg-1d-1. An everted sleeve of intestine 4 cm long obtained from mid-jejunum was securely incubated in Kreb's solution with radioactive dipeptide (3H-glycylsarcosine, 3H-Gly-Sar,10 μCi/ml) at 37 ℃ for 15 min to measure the effects of uptake and transport of PepT1 of small intestinal epithelial cells in normal and severe scald rats.RESULTS: Abundant blood supply to intestine and mesentery was observed in normal and scald rats administered rhGH,while less supply of blood to intestine and mesentery was observed in rats without rhGH. Compared with controls, the transport of dipeptide in normal rats with injection of rhGH was not significantly increased (P=0.1926), while the uptake was significantly increased (P=0.0253). The effects of transport and uptake of PepT1 in scald rats with injection of rhGH were significantly increased (P=0.0082, 0.0391).CONCLUSION: Blood supply to intestine and mesentery of rats was increased following injection of rhGH. The effects of uptake and transport of dipeptide transporters in small intestinal epithelial cells of rats with severe scald were markedly up-regulated by rhGH.

  2. Fate of nitrogen for subsurface drip dispersal of effluent from small wastewater systems

    Science.gov (United States)

    Beggs, R. A.; Hills, D. J.; Tchobanoglous, G.; Hopmans, J. W.

    2011-09-01

    Subsurface drip irrigation systems apply effluent from onsite wastewater systems in a more uniform manner at a lower rate than has been possible with other effluent dispersal methods. The effluent is dispersed in a biologically active part of the soil profile for optimal treatment and where the water and nutrients can be utilized by landscape plants. Container tests were performed to determine the fate of water and nitrogen compounds applied to packed loamy sand, sandy loam, and silt loam soils. Nitrogen removal rates measured in the container tests ranged from 63 to 95% despite relatively low levels of available carbon. A Hydrus 2D vadose zone model with nitrification and denitrification rate coefficients calculated as a function of soil moisture content fit the container test results reasonably well. Model results were sensitive to the denitrification rate moisture content function. Two-phase transport parameters were needed to model the preferential flow conditions in the finer soils. Applying the model to generic soil types, the greatest nitrogen losses (30 to 70%) were predicted for medium to fine texture soils and soils with restrictive layers or capillary breaks. The slow transport with subsurface drip irrigation enhanced total nitrogen losses and plant nitrogen uptake opportunity.

  3. Fate of nitrogen for subsurface drip dispersal of effluent from small wastewater systems.

    Science.gov (United States)

    Beggs, R A; Hills, D J; Tchobanoglous, G; Hopmans, J W

    2011-09-25

    Subsurface drip irrigation systems apply effluent from onsite wastewater systems in a more uniform manner at a lower rate than has been possible with other effluent dispersal methods. The effluent is dispersed in a biologically active part of the soil profile for optimal treatment and where the water and nutrients can be utilized by landscape plants. Container tests were performed to determine the fate of water and nitrogen compounds applied to packed loamy sand, sandy loam, and silt loam soils. Nitrogen removal rates measured in the container tests ranged from 63 to 95% despite relatively low levels of available carbon. A Hydrus 2D vadose zone model with nitrification and denitrification rate coefficients calculated as a function of soil moisture content fit the container test results reasonably well. Model results were sensitive to the denitrification rate moisture content function. Two-phase transport parameters were needed to model the preferential flow conditions in the finer soils. Applying the model to generic soil types, the greatest nitrogen losses (30 to 70%) were predicted for medium to fine texture soils and soils with restrictive layers or capillary breaks. The slow transport with subsurface drip irrigation enhanced total nitrogen losses and plant nitrogen uptake opportunity. PMID:21708414

  4. Simultaneous Transport of Two Bacterial Strains in Intact Cores from Oyster, Virginia: Biological Effects and Numerical Modeling

    OpenAIRE

    Dong, Hailiang; Rothmel, Randi; Onstott, Tullis C.; Fuller, Mark E.; DeFlaun, Mary F.; Streger, Sheryl H.; Dunlap, Robb; Fletcher, Madilyn

    2002-01-01

    The transport characteristics of two adhesion-deficient, indigenous groundwater strains, Comamonas sp. strain DA001 and Erwinia herbicola OYS2-A, were studied by using intact sediment cores (7 by 50 cm) from Oyster, Va. Both strains are gram-negative rods (1.10 by 0.56 and 1.56 by 0.46 μm, respectively) with strongly hydrophilic membranes and a slightly negative surface charge. The two strains exhibited markedly different behaviors when they were transported through granular porous sediment. ...

  5. BETR Global - A geographically explicit global-scale multimedia contaminant fate model

    Energy Technology Data Exchange (ETDEWEB)

    Macleod, M.; Waldow, H. von; Tay, P.; Armitage, J. M.; Wohrnschimmel, H.; Riley, W.; McKone, T. E.; Hungerbuhler, K.

    2011-04-01

    We present two new software implementations of the BETR Global multimedia contaminant fate model. The model uses steady-state or non-steady-state mass-balance calculations to describe the fate and transport of persistent organic pollutants using a desktop computer. The global environment is described using a database of long-term average monthly conditions on a 15{sup o} x 15{sup o} grid. We demonstrate BETR Global by modeling the global sources, transport, and removal of decamethylcyclopentasiloxane (D5).

  6. The Most Important Concept of Transport and Circulatory Systems: Turkish Biology Student Teachers' Cognitive Structure

    Science.gov (United States)

    Kurt, Hakan; Ekici, Gulay; Aksu, Ozlem; Aktas, Murat

    2013-01-01

    The purpose of this study is to determine biology student teachers' cognitive structure with regard to "Blood". Qualitative research method has been used. The free word association test and the draw-write technique have been used in collection of data. The data obtained have been evaluated and divided into categories based on…

  7. ASSESSMENT OF THE SUBSURFACE FATE OF MONOETHANOLAMINE

    Energy Technology Data Exchange (ETDEWEB)

    James A. Sorensen; John R. Gallagher; Lori G. Kays

    2000-05-01

    Burial of amine reclaimer unit sludges and system filters has resulted in contamination of soil at the CanOxy Okotoks decommissioned sour gas-processing plant with amines, amine byproducts, and salts. A three-phase research program was devised to investigate the natural attenuation process that controls the subsurface transport and fate of these contaminants and to apply the results toward the development of a strategy for the remediation of this type of contamination in soils. Phase I experimental activities examined interactions between monoethanolamine (MEA) and sediment, the biodegradability of MEA in soils at various concentrations and temperatures, and the biodegradability of MEA sludge contamination in a soil slurry bioreactor. The transport and fate of MEA in the subsurface was found to be highly dependant on the nature of the release, particularly MEA concentration and conditions of the subsurface environment, i.e., pH, temperature, and oxygen availability. Pure compound biodegradation experiments in soil demonstrated rapid biodegradation of MEA under aerobic conditions and moderate temperatures (>6 C). Phase II landfarming activities confirmed that these contaminants are readily biodegradable in soil under ideal laboratory conditions, yet considerable toxicity was observed in the remaining material. Examination of water extracts from the treated soil suggested that the toxicity is water-soluble. Phase II activities led to the conclusion that landfarming is not the most desirable bioremediation technique; however, an engineered biopile with a leachate collection system could remove the remaining toxic fraction from the soil. Phase III was initiated to conduct field-based experimental activities to examine the optimized remediation technology. A pilot-scale engineered biopile was constructed at a decommissioned gas-sweetening facility in Okotoks, Alberta, Canada. On the basis of a review of the analytical and performance data generated from soil and

  8. The Fated Death of Tess

    Institute of Scientific and Technical Information of China (English)

    李莉

    2012-01-01

      The theme of this essay is about the fated deaths of Tess.The emphasis is‘inevitability’. Tess’s Death is mainly due to the social influence and man-made factors. Because of the low social status and moral conceptions, there is no living room left for Tess. Her parents push her get closer to her tragedy as well. Alec and Angel are the two persons who directly and indirectly cause Tess’s death. In addition, there are also some subjective causes for her doom. The symbolic red in the novel intentionally indicates the’inevitability’of her death.

  9. Gated supramolecular chemistry in hybrid mesoporous silica nanoarchitectures: controlled delivery and molecular transport in response to chemical, physical and biological stimuli.

    Science.gov (United States)

    Alberti, Sebastián; Soler-Illia, Galo J A A; Azzaroni, Omar

    2015-04-11

    This review presents and discusses recent advances in the emerging field of "gated nanochemistry", outlining the substantial progress made so far. The development of hybrid mesoporous silica with complex tailored pore nanoarchitectures bridges the gap between molecular materials and the requirements of nanodevices for controlled nanoscale chemistry. In the last decade, membranes, particles and thin film porous architectures have been designed, synthesized and selectively modified by molecular, polymeric, organometallic or biologically active groups. The exquisite manipulation of mesopore morphology and interconnection combined with molecular or supramolecular functionalities, and the intrinsic biological compatibility of silica have made these materials a potential platform for selective sensing and drug delivery. The wide répertoire of these hard-soft architectures permit us to envisage sophisticated intelligent nano-systems that respond to a variety of external stimuli such as pH, redox potential, molecule concentration, temperature, or light. Transduction of these stimuli into a predefined response implies exploiting spatial and physico-chemical effects such as charge distribution, steric constraints, equilibria displacements, or local changes in ionic concentration, just to name a few examples. As expected, this "positional mesochemistry" can be only attained through the concerted control of assembly, surface tailoring and, confinement conditions, thus giving birth to a new class of stimuli-responsive materials with modulable transport properties. As a guiding framework the emerging field of "gated nanochemistry" offers methodologies and tools for building up stimuli-sensitive porous architectures equipped with switchable entities whose transport properties can be triggered at will. The gated nanoscopic hybrid materials discussed here not only herald a new era in the integrative design of "smart" drug delivery systems, but also give the reader a perspective of

  10. An evaluation of the environmental fate and behavior of munitions material (TNT, RDX) in soil and plant systems: Environmental fate and behavior of RDX

    Energy Technology Data Exchange (ETDEWEB)

    Cataldo, D.A.; Harvey, S.D.; Fellows, R.J.

    1990-08-01

    The objective of the present investigation was to elucidate the environmental behavior and fate of hexahydro-1,3,5-trinitro-1,3,5- triazine (RDX), particularly as related to its transport and chemical form in the food chain. To meet this goal, we needed to adapt and develop suitable analytical methodology to fractionate and characterize both RDX and RDX-derived residues in soil and plant matrices. Using the methodology that we developed, we assessed the chemical and physical fate of RDX in soils and plants. In general, the plant availability and plant mobility of RDX is substantially greater than that previously reported for TNT. 30 refs., 27 figs., 26 tabs.

  11. Characterization of the environmental fate of Bacillus thuringiensis var. kaurstaki (Btk) after pest eradication efforts in Seattle, WA and Fairfax county, VA

    Energy Technology Data Exchange (ETDEWEB)

    Ticknor, Lawrence [Los Alamos National Laboratory; Van Cuyk, Sheila M [Los Alamos National Laboratory; Deshpande, Alina [Los Alamos National Laboratory; Omberg, Kristin M [Los Alamos National Laboratory

    2008-01-01

    Understanding the fate of biological agents in the environment will be critical to recovery and restoration efforts after a biological attack. Los Alamos National Laboratory (LANL) is conducting experiments in the Seattle, WA and Fairfax County, VA areas to study agent fate in urban environments. As part of their gypsy moth suppression efforts, Washington State and Fairfax County have sprayed Bacillus thuringiensis var. kurstaki (Btk), a common organic pesticide for decades. Many of the spray zones have been in or near urban areas. LANL has collected surface and bulk samples from historical Seattle spray zones to characterize how long Btk persists at detectable levels in the environment, and how long it remains viable in different environmental matrices. This work will attempt to address three questions. First, how long does the agent remain viable at detectable levels? Second, what is the approximate magnitude and duration of resuspension? And third, does the agent transport into buildings? Data designed to address the first question will be presented. Preliminary results indicate Btk remains viable in the environment for at least two years.

  12. Neural Induction, Neural Fate Stabilization, and Neural Stem Cells

    Directory of Open Access Journals (Sweden)

    Sally A. Moody

    2002-01-01

    Full Text Available The promise of stem cell therapy is expected to greatly benefit the treatment of neurodegenerative diseases. An underlying biological reason for the progressive functional losses associated with these diseases is the extremely low natural rate of self-repair in the nervous system. Although the mature CNS harbors a limited number of self-renewing stem cells, these make a significant contribution to only a few areas of brain. Therefore, it is particularly important to understand how to manipulate embryonic stem cells and adult neural stem cells so their descendants can repopulate and functionally repair damaged brain regions. A large knowledge base has been gathered about the normal processes of neural development. The time has come for this information to be applied to the problems of obtaining sufficient, neurally committed stem cells for clinical use. In this article we review the process of neural induction, by which the embryonic ectodermal cells are directed to form the neural plate, and the process of neural�fate stabilization, by which neural plate cells expand in number and consolidate their neural fate. We will present the current knowledge of the transcription factors and signaling molecules that are known to be involved in these processes. We will discuss how these factors may be relevant to manipulating embryonic stem cells to express a neural fate and to produce large numbers of neurally committed, yet undifferentiated, stem cells for transplantation therapies.

  13. FY08 LDRD Final Report Stem Cell Fate Decisions

    Energy Technology Data Exchange (ETDEWEB)

    Hiddessen, A

    2009-03-02

    A detailed understanding of the biological control of fate decisions of stem and progenitor cells is needed to harness their full power for tissue repair and/or regeneration. Currently, internal and external factors that regulate stem cell fate are not fully understood. We aim to engineer biocompatible tools to facilitate the measurement and comparison of the roles and significance of immobilized factors such as extracellular matrix and signaling peptides, synergistic and opposing soluble factors and signals, and cell-to-cell communication, in stem cell fate decisions. Our approach is based on the development of cell microarrays to capture viable stem/progenitor cells individually or in small clusters onto substrate-bound signals (e.g. proteins), combined with conventional antibody and customized subcellular markers made in-house, to facilitate tracking of cell behavior during exposure to relevant signals. Below we describe our efforts, including methods to manipulate a model epithelial stem cell system using a custom subcellular reporter to track and measure cell signaling, arrays with surface chemistry that support viable cells and enable controlled presentation of immobilized signals to cells on the array and fluorescence-based measurement of cell response, and successful on-array tests via conventional immunofluorescence assays that indicate correct cell polarity, localization of junctional proteins, and phenotype, properties which are essential to measuring true cell responses.

  14. Caenorhabditis elegans vulval cell fate patterning

    Science.gov (United States)

    Félix, Marie-Anne

    2012-08-01

    The spatial patterning of three cell fates in a row of competent cells is exemplified by vulva development in the nematode Caenorhabditis elegans. The intercellular signaling network that underlies fate specification is well understood, yet quantitative aspects remain to be elucidated. Quantitative models of the network allow us to test the effect of parameter variation on the cell fate pattern output. Among the parameter sets that allow us to reach the wild-type pattern, two general developmental patterning mechanisms of the three fates can be found: sequential inductions and morphogen-based induction, the former being more robust to parameter variation. Experimentally, the vulval cell fate pattern is robust to stochastic and environmental challenges, and minor variants can be detected. The exception is the fate of the anterior cell, P3.p, which is sensitive to stochastic variation and spontaneous mutation, and is also evolving the fastest. Other vulval precursor cell fates can be affected by mutation, yet little natural variation can be found, suggesting stabilizing selection. Despite this fate pattern conservation, different Caenorhabditis species respond differently to perturbations of the system. In the quantitative models, different parameter sets can reconstitute their response to perturbation, suggesting that network variation among Caenorhabditis species may be quantitative. Network rewiring likely occurred at longer evolutionary scales.

  15. Environmental fate and behaviour of nanomaterials

    DEFF Research Database (Denmark)

    Hartmann, Nanna Isabella Bloch; Skjolding, Lars Michael; Hansen, Steffen Foss;

    In the current report, the existing knowledge on the fate of nanomaterials in the environment is reviewed and the major knowledge gaps are identified.......In the current report, the existing knowledge on the fate of nanomaterials in the environment is reviewed and the major knowledge gaps are identified....

  16. Environmental fate of tungsten from military use

    Energy Technology Data Exchange (ETDEWEB)

    Clausen, Jay L. [Research and Development Center, Cold Regions Research and Engineering Laboratory, 72 Lyme Road, Hanover, New Hampshire, 03755 (United States)], E-mail: Jay.L.Clausen@erdc.usace.army.mil; Korte, Nic [1946 Clover Ct., Grand Junction, Colorado, 81506 (United States)

    2009-04-01

    This manuscript describes the distribution, fate and transport of tungsten used in training rounds at three small arms ranges at Camp Edwards on the Massachusetts Military Reservation (MMR), USA. Practice with tungsten/nylon rounds began in 2000 subsequent to a 1997 US Environmental Protection Agency ban on training with lead. Training with the tungsten rounds was halted in 2005 because of concerns regarding tungsten's environmental mobility and potential toxicity. This study, therefore, examines how tungsten partitions in the environment when fired on a small arms training range. Soil sampling revealed surface soil concentrations, highest at the berm face, up to 2080 mg/kg. Concentrations decreased rapidly with depth-at least by an order of magnitude by 25 cm. Nonetheless, tungsten concentrations remained above background to at least 150 cm. Pore-water samples from lysimeters installed in berm areas revealed a range of concentrations (< 1-400 mg/L) elevated with respect to background although there was no discernable trend with depth. Groundwater monitoring well samples collected approximately 30 m below ground surface showed tungsten (0.001-0.56 mg/L) attributable to range use.

  17. Resolving the Impact of Biological Processes on Water Transport in Unsaturated Porous Media Through Nuclear Magnetic Resonance Micro-Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Seymour, Joseph D.

    2005-06-01

    The magnetic resonance microscopy (MRM) work at Montana State University has extended the imaging of a single biofilm in a 1 mm capillary reactor to correlate T2 magnetic relaxation maps displaying biofilm structure with the corresponding velocity patterns in three dimensions in a Staphylococcus epidermidis biofilm fouled square capillary. A square duct geometry is chosen to provide correlation with existing experiments and simulations, as research bioreactors tend to be of square or rectangular cross section for optical or microelectrode access. The spatially resolved velocity data provide details on the impact of biofilm induced advection on mass transport from the bulk fluid to the biofilm and through the capillary bioreactor.

  18. Fate of organochlorine 14C-dicofol in a lab-scale wastewater treatment

    OpenAIRE

    Jaime L. M. Oliveira; Langenbach, Tomaz; Dezotti, Márcia

    2008-01-01

    The fate of organochlorine 14C-dicofol in activated sludge process was investigated. Results showed that the major part of radioactivity remained adsorbed on biological sludge. Consequently, its final disposal deserves special attention. The small amounts of dicofol, biotransformed or not, which remained in the treated effluent could contaminate receiving bodies.

  19. Prediction of the Fate of Oxytetracycline and Oxolinic Acid in a Fish Pond Using Simulation Model -A Preliminary Study

    OpenAIRE

    Phong, Thai Khanh; Nhung, Dang Thi Tuyet; Hiramatsu, Kazuaki; Watanabe, Hirozumi

    2009-01-01

    The fate of two popular antibiotics, oxytetracycline and oxolinic acid, in a fish pond were simulated using a computational model. The VDC model, which is designed based on a model for predicting pesticide fate and transport in paddy fields, was modified to take into account the differences between the pond and the paddies as well as those between the fish and the rice plant behaviors. The pond conditions were set following the typical practice in South East Asia aquaculture. The two antibiot...

  20. The Fate of Dissolved Creosote Compounds in an Intact Fratured Clay Column

    DEFF Research Database (Denmark)

    Broholm, Kim; Arvin, Erik; Hansen, Asger;

    1995-01-01

    The fate of 16 different organics typical for creosote was studied under aerobic conditions in a large intact fractured clay column experiment. Some of the organics (benzene, toluene, o-xylene, phenol, and o-cresol) were transported at the same rate as bromide through the fractured clay, whereas ...

  1. Species-specific fate of bacteria in house flies and impact on vector potential for pathogens

    Science.gov (United States)

    House flies ingest bacteria during filth-feeding and consequently can transport microbes from septic environments to human habitats and food. Vector potential is influenced both by flies encountering pathogens and by the fate of bacteria in the fly alimentary canal. In order for pathogens to be tran...

  2. Gas transport processes in sea ice: How convection and diffusion processes might affect biological imprints, a challenge for modellers

    DEFF Research Database (Denmark)

    Tison, J.-L.; Zhou, Shaola J. G.; Thomas, D. N.;

    2012-01-01

    ice cover. These rates were however obtained surmising that neither convection, nor diffusion had affected the gas concentration profiles in the ice between discrete ice core collections. This paper discusses examples from three different field surveys (the above-mentioned Barrow experiment......, the INTERICE IV tank experiment in Hamburg and a short field survey close to the Kapisilit locality in the South-East Greenland fjords) where convection or diffusion processes have clearly affected the temporal evolution of the gas profiles in the ice, therefore potentially affecting biological signatures....... The INTERICE IV and Barrow experiment show that the initial equilibrium dissolved gas entrapment within the skeletal layer basically governs most of the profiles higher up in the sea ice cover during the active sea ice growth. However, as the ice layers age and cool down under the temperature gradient, bubble...

  3. New fluorinated ligands for the dopamine transporter. Synthesis and first biological evaluation in pig and rat brain

    Energy Technology Data Exchange (ETDEWEB)

    Krebs, B.; Sihver, W.; Coenen, H.H. [Forschungszentrum Juelich (Germany). Inst. fuer Nuklearchemie

    2004-07-01

    A change in the density of the dopamine transporter (DAT) is a widely accepted indicator for the integrity of the presynaptic nigrostriatal dopaminergic system. In spite of the advantageous properties of fluorine-18 for PET imaging up to now there is no suitable radiofluorinated DAT ligand available although numerous investigations have been performed by different working groups. Presently the SPECT ligand [{sup 123}I]FP-CIT known as DaTSCAN is the only commercially available DAT radiotracer for routine clinical use. The present study describes the syntheses of new fluorinated tropanes as potential DAT ligands (Figure) and their first in vitro evaluation in pig and rat brain. Several known DAT ligands are also synthesized and evaluated as standards for comparison. (orig.)

  4. Fate mapping of dendritic cells

    Directory of Open Access Journals (Sweden)

    Barbara Ursula Schraml

    2015-05-01

    Full Text Available Dendritic cells (DCs are a heterogeneous group of mononuclear phagocytes with versatile roles in immunity. They are classified predominantly based on phenotypic and functional properties, namely their stellate morphology, expression of the integrin CD11c and major histocompatibility class II molecules, as well as their superior capacity to migrate to secondary lymphoid organs and stimulate naïve T cells. However, these attributes are not exclusive to DCs and often change within inflammatory or infectious environments. This led to debates over cell identification and questioned even the mere existence of DCs as distinct leukocyte lineage. Here, we review experimental approaches taken to fate map DCs and discuss how these have shaped our understanding of DC ontogeny and lineage affiliation. Considering the ontogenetic properties of DCs will help to overcome the inherent shortcomings of purely phenotypic- and function-based approaches to cell definition and will yield a more robust way of DC classification.

  5. Vesicular monoamine transporter protein expression correlates with clinical features, tumor biology, and MIBG avidity in neuroblastoma: a report from the Children's Oncology Group

    Energy Technology Data Exchange (ETDEWEB)

    Temple, William; Mendelsohn, Lori; Nekritz, Erin; Gustafson, W.C.; Matthay, Katherine K. [UCSF School of Medicine, Department of Pediatrics, San Francisco, CA (United States); UCSF Benioff Children' s Hospital, San Francisco, CA (United States); Kim, Grace E. [UCSF School of Medicine, Department of Pathology, San Francisco, CA (United States); Lin, Lawrence; Giacomini, Kathy [UCSF School of Pharmacy, Department of Bioengineering and Therapeutic Sciences, San Francisco, CA (United States); Naranjo, Arlene; Van Ryn, Collin [University of Florida, Children' s Oncology Group Statistics and Data Center, Gainesville, FL (United States); Yanik, Gregory A. [University of Michigan, CS Mott Children' s Hospital, Ann Arbor, MI (United States); Kreissman, Susan G. [Duke University Medical Center, Durham, NC (United States); Hogarty, Michael [University of Pennsylvania, Children' s Hospital of Philadelphia and Perelman School of Medicine, Philadelphia, PA (United States); DuBois, Steven G. [UCSF School of Medicine, Department of Pediatrics, San Francisco, CA (United States); UCSF Benioff Children' s Hospital, San Francisco, CA (United States); UCSF School of Medicine, San Francisco, CA (United States)

    2016-03-15

    Vesicular monoamine transporters 1 and 2 (VMAT1 and VMAT2) are thought to mediate MIBG uptake in adult neuroendocrine tumors. In neuroblastoma, the norepinephrine transporter (NET) has been investigated as the principal MIBG uptake protein, though some tumors without NET expression concentrate MIBG. We investigated VMAT expression in neuroblastoma and correlated expression with MIBG uptake and clinical features. We evaluated VMAT1 and VMAT2 expression by immunohistochemistry (IHC) in neuroblastoma tumors from 76 patients with high-risk metastatic disease treated in a uniform cooperative group trial (COG A3973). All patients had baseline MIBG diagnostic scans centrally reviewed. IHC results were scored as the product of intensity grading (0 - 3+) and percent of tumor cells expressing the protein of interest. The association between VMAT1 and VMAT2 scores and clinical and biological features was tested using Wilcoxon rank-sum tests. Patient characteristics were typical of high-risk neuroblastoma, though the cohort was intentionally enriched in patients with MIBG-nonavid tumors (n = 20). VMAT1 and VMAT2 were expressed in 62 % and 75 % of neuroblastoma tumors, respectively. VMAT1 and VMAT2 scores were both significantly lower in MYCN amplified tumors and in tumors with high mitotic karyorrhectic index. MIBG-avid tumors had significantly higher VMAT2 scores than MIBG-nonavid tumors (median 216 vs. 45; p = 0.04). VMAT1 expression did not correlate with MIBG avidity. VMAT1 and VMAT2 are expressed in the majority of neuroblastomas. Expression correlates with other biological features. The expression level of VMAT2 but not that of VMAT1 correlates with avidity for MIBG. (orig.)

  6. A planar conducting micro-loop structure for transportation of magnetic beads: An approach towards rapid sensing and quantification of biological entities

    KAUST Repository

    Gooneratne, Chinthaka Pasan

    2012-03-01

    Magnetic beads are utilized effectively in a wide variety of medical applications due to their small size, biocompatibility and large surface to volume ratio. Microfluidic lab-on-a-chip (LOC) devices, which utilize magnetic beads, are promising tools for accurate and rapid cell sorting and counting. Effective manipulation of beads is a critical factor for the performance of LOC devices. In this paper we propose a planar conducting micro-loop structure to trap, manipulate and transport magnetic beads. Current through the micro-loops produces magnetic field gradients that are proportional to the force required to manipulate the beads. Numerical analyses were performed to study the magnetic forces and their spatial distributions. Experimental results showed that magnetic beads could not only be transported towards a target region, e.g., for sensing purposes, but also the trapping rate could be increased by switching current between the different loops in the micro-loop structure. This method could lead to rapid and accurate quantification of biological entities tagged with magnetic beads. Copyright © 2012 American Scientific Publishers. All rights reserved.

  7. Biological fate of butylated hydroxytoluene (BHT) in rats, (3)

    International Nuclear Information System (INIS)

    Butylated hydroxytoluene (BHT) is the chemical widely used not only as the antioxidant for food additives but also as that for containers. 14C-BHT was administered orally to rats, and the subcellular distribution and the change of existence mode in course of time in kidneys were investigated, also the separation and identification of the metabolites in urine were tested. Radioactivity was determined with a liquid scintillation counter. Subcellular fractions were separated by the gel-filtration with Sephadex, and thin layer autoradiography was performed, and radioactive parts were confirmed. The radioactivity in each fraction of the reference group showed the highest 6 hours after the administration, and then it decreased rapidly, but the radioactivity in microsome fraction was the highest at 12 hours after the administration. Only BHT acids was identified out of the metabolites in urine by the thin layer autoradiography, and further investigation will be made about other metabolites. (Kobatake, H.)

  8. Fate of estrogens in biological treatment of concentrated black water

    NARCIS (Netherlands)

    Mes, de T.Z.D.

    2007-01-01

    De Nederlandse anaerobe zuiveringsinstallaties kunnen onvoldoende oestrogenen afbreken, ontdekte De Mes. Daarnaast ontdekte de promovenda dat het probleem nog een graadje serieuzer was dan ze aanvankelijk had gedacht. Enkele tientallen procenten van de vrouwelijke hormonen verlaten het lichaam als e

  9. In vivo degeneration and the fate of inorganic nanoparticles.

    Science.gov (United States)

    Feliu, Neus; Docter, Dominic; Heine, Markus; Del Pino, Pablo; Ashraf, Sumaira; Kolosnjaj-Tabi, Jelena; Macchiarini, Paolo; Nielsen, Peter; Alloyeau, Damien; Gazeau, Florence; Stauber, Roland H; Parak, Wolfgang J

    2016-05-01

    What happens to inorganic nanoparticles (NPs), such as plasmonic gold or silver, superparamagnetic iron oxide, or fluorescent quantum dot NPs after they have been administrated to a living being? This review discusses the integrity, biodistribution, and fate of NPs after in vivo administration. The hybrid nature of the NPs is described, conceptually divided into the inorganic core, the engineered surface coating comprising of the ligand shell and optionally also bio-conjugates, and the corona of adsorbed biological molecules. Empirical evidence shows that all of these three compounds may degrade individually in vivo and can drastically modify the life cycle and biodistribution of the whole heterostructure. Thus, the NPs may be decomposed into different parts, whose biodistribution and fate would need to be analyzed individually. Multiple labeling and quantification strategies for such a purpose will be discussed. All reviewed data indicate that NPs in vivo should no longer be considered as homogeneous entities, but should be seen as inorganic/organic/biological nano-hybrids with complex and intricately linked distribution and degradation pathways. PMID:26862602

  10. Potential fate of SOC eroded from natural crusted soil surface under simulated wind driven storm

    Science.gov (United States)

    Xiao, Liangang; Fister, Wolfgang; Greenwood, Philip; Hu, Yaxian; Kuhn, Nikolaus J.

    2016-04-01

    Improving the assessment of the impact of soil erosion on carbon (C) cycling requires a better understanding of the redistribution of eroded sediment and associated soil organic carbon (SOC) across agricultural landscapes. Recent studies conducted on dry-sieved aggregates in the laboratory demonstrated that aggregation can profoundly skew SOC redistribution and its subsequent fate by accelerating settling velocities of aggregated sediment compared to mineral grains, which in turn can increase SOC mineralization into greenhouse gases. However, the erodibility of the soil in the field is more variable than in the laboratory due to tillage, crus formation, drying-wetting and freeze-thaw cycles, and biological effects. This study aimed to investigate the potential fate of the SOC eroded from naturally developed soil surface and to compare the observations with those made in the laboratory. Simulated, short, high intensity wind driven storms were conducted on a crusted loam in the field. The sediments were fractionated with a settling tube according to their potential transport distances. The soil mass, SOC concentration and cumulative 80-day CO2 emission of each fraction were identified. The results show: 1) 53% of eroded sediment and 62% of eroded SOC from the natural surface in the field would be deposited across landscapes, which is six times and three times higher compared to that implied by mineral grains, respectively; 2) the preferential deposition of SOC-rich fast-settling sediment potentially releases approximately 50% more CO2 than the same layer of the non-eroded soil; 3) the respiration of the slow-settling fraction that is potentially transported to the aquatic systems was much more active compared to the other fractions and the bulk soil. Our results confirm in general the conclusions drawn from laboratory and thus demonstrate that aggregation can affect the redistribution of sediment associated SOC under field conditions, including an increase in

  11. The fate of volatiles in mid-ocean ridge magmatism

    CERN Document Server

    Keller, Tobias; Hirschmann, Marc M

    2016-01-01

    Deep-Earth volatile cycles couple the mantle with near-surface reservoirs. Volatiles are emitted by volcanism and, in particular, from mid-ocean ridges, which are the most prolific source of basaltic volcanism. Estimates of volatile extraction from the asthenosphere beneath ridges typically rely on measurements of undegassed lavas combined with simple petrogenetic models of the mean degree of melting. Estimated volatile fluxes have large uncertainties; this is partly due to a poor understanding of how volatiles are transported by magma in the asthenosphere. Here, we assess the fate of mantle volatiles through numerical simulations of melting and melt transport at mid-ocean ridges. Our simulations are based on two-phase, magma/mantle dynamics theory coupled to an idealised thermodynamic model of mantle melting in the presence of water and carbon dioxide. We combine simulation results with catalogued observations of all ridge segments to estimate a range of likely volatile output from the global mid-ocean ridge...

  12. Environmental fate of natural radioactive contaminants in fertilizers and phosphogypsum

    Energy Technology Data Exchange (ETDEWEB)

    Batalha, Marcia Salamoni; Genuchten, Martinus Theodorus van, E-mail: msbatalha@oi.com.b, E-mail: rvangenuchten@yahoo.co [Federal University of Rio de Janeiro (LTTC/COPPE/UFRJ), RJ (Brazil). Dept. of Mechanical Engineering. Lab. de Transmissao e Tecnologia do Calor; Bezerra, Camila Rosa, E-mail: camila.rosabz@gmail.co [Federal University of Rio de Janeiro (COPPE/UFRJ), RJ (Brazil). Dept. of Civil Engineering; Pontedeiro, Elizabeth May, E-mail: bettymay@cnen.gov.b [Brazilian Nuclear Energy Commission (CNEN), Rio de Janeiro, RJ (Brazil)

    2010-07-01

    Agricultural soils often require the use of fertilizers and soil conditioners for optimal production. Phosphate fertilizers produced from igneous phosphate rock often contain small amounts of natural radionuclides (notably uranium and thorium), while the byproduct phosphogypsum (dihydrated calcium sulfate) is typically enriched in radium and lead. It is important to understand the long-term fate of these radionuclides when routinely applied via fertilizers ({sup 238}U and {sup 234}U) and phosphogypsum as an amendment ({sup 226}Ra and {sup 210}Pb) to agricultural lands. This study addresses the results of modeling their transport in a typical Cerrado soil profile. The HYDRUS-1D code was used to compare possible soil and groundwater pollution scenarios following the long term use of fertilizers and phosphogypsum in agricultural operations. Results using the equilibrium transport approach suggest that radionuclide concentrations originating from the use of phosphate fertilizers and phosphogypsum are relatively modest and will not pose a major risk to polluting underlying groundwater resources. (author)

  13. Environmental fate of natural radioactive contaminants in fertilizers and phosphogypsum

    International Nuclear Information System (INIS)

    Agricultural soils often require the use of fertilizers and soil conditioners for optimal production. Phosphate fertilizers produced from igneous phosphate rock often contain small amounts of natural radionuclides (notably uranium and thorium), while the byproduct phosphogypsum (dihydrated calcium sulfate) is typically enriched in radium and lead. It is important to understand the long-term fate of these radionuclides when routinely applied via fertilizers (238U and 234U) and phosphogypsum as an amendment (226Ra and 210Pb) to agricultural lands. This study addresses the results of modeling their transport in a typical Cerrado soil profile. The HYDRUS-1D code was used to compare possible soil and groundwater pollution scenarios following the long term use of fertilizers and phosphogypsum in agricultural operations. Results using the equilibrium transport approach suggest that radionuclide concentrations originating from the use of phosphate fertilizers and phosphogypsum are relatively modest and will not pose a major risk to polluting underlying groundwater resources. (author)

  14. Potency and fate specification in CNS stem cell populations in vitro.

    Science.gov (United States)

    Ravin, Rea; Hoeppner, Daniel J; Munno, David M; Carmel, Liran; Sullivan, Jim; Levitt, David L; Miller, Jennifer L; Athaide, Christopher; Panchision, David M; McKay, Ronald D G

    2008-12-01

    To realize the promise of stem cell biology, it is important to identify the precise time in the history of the cell when developmental potential is restricted. To achieve this goal, we developed a real-time imaging system that captures the transitions in fate, generating neurons, astrocytes, and oligodendrocytes from single CNS stem cells in vitro. In the presence of bFGF, tripotent cells normally produce specified progenitors through a bipotent intermediate cell type. Surprisingly, the tripotent state is reset at each passage. The cytokine CNTF is thought to instruct multipotent cells to an astrocytic fate. We demonstrate that CNTF both directs astrogliogenesis from tripotent cells, bypassing two of the three normal bipotent intermediates, and later promotes the expansion of specified astrocytic progenitors. These results show how discrete cell types emerge from a multipotent cell and provide a strong basis for future studies to determine the molecular basis of fate specification.

  15. Application of Multimedia Fugacity Model to Assess the Environmental Fate of Benzo (a Pyrene

    Directory of Open Access Journals (Sweden)

    Theoneste Ntakirutimana

    2012-07-01

    Full Text Available This study was undertaken in order to assess the environmental fate of Benzo (a pyrene. We have highlighted the behavior of Benzo (a pyrene in multimedia environment or biosphere of air, water, soil and sediments. Equilibrium Criterion (EQC model which is used to evaluate the environmental fate of Polycyclic Aromatic Hydrocarbons (PAHs is used as our tool. The structure of the model and the required input data are presented. By undertaking a sequence of level I, II and III calculations, increasing information is obtained about the chemical’s partitioning, environmental process and chemical characteristics that influence chemical fate, its susceptibility to transformation and transport from one media to another. Output data, consisting of diagrams, give a complete picture of Benzo (a pyrene’s fate in an evaluative environment. The role of this model as a tool for assessing the fate of Benzo (a pyrene is discussed. We suggested that this assessment can serve as a template which can be applied to other chemicals and groups of chemicals which are present in the environment.

  16. Biological transport of tetracycline hydrochloride by human periodontal ligament fibroblasts%人牙周膜成纤维细胞对四环素的跨膜转运

    Institute of Scientific and Technical Information of China (English)

    刘宇; 刘洪臣; 吴霞; 鄂玲玲; 冷斌

    2008-01-01

    Objective To investigate biological transport of tetracycline hydrochloride by human periodontal ligament fibmblasts(HPDLF) for verifying the hypothesis of delivering medicine to the periodonfium and whole bodv through the root canal.Methods HPDLF and MC3,13-E1 cells were ineubated in antibiotics solutions. The intracellulaF antibiotics contents were measured by high performance liquid chromatography(HPLC) and the cell total protein was measured by bradford protein assay.Results The intracellular contents increased with ineubation time. The extracellular medicine concentration had effect on the intracellular contents. Conclusions Tetracycline hydrochloride can be transported into HPDLF with incubation and this transport is time-dependent and concentration-dependent.%目的 研究人牙周膜成纤维细胞(human periodontal ligament fibroblasts,HPDLF)对四环素的跨膜转运,为通过根管局部或全身给药假说提供实验依据.方法 盐酸四环素溶液孵育HPDLF和MC3T3-E1细胞,超声破碎细胞后,高效液相色谱法测定胞内药物含量,考马斯亮蓝法测定细胞蛋白质量.结果 10 mg/L四环素孵育1、5、10 min后细胞内四环素含量与细胞蛋白质量的比值分别为(0.192±0.008)、(0.212±0.082)、(0.620±0.075)ng/μg.20 mg/L四环素孵育5 min后细胞内四环素含量与细胞蛋白质量的比值为(0.503±0.056)ng/μg.10 mg/L四环素孵育5 min后MC3T3-E1细胞内四环素含量与细胞蛋白质量的比值为(0.666±0.560)ng/μg.结论 HPDLF可跨膜转运四环素.转运与孵育时间及细胞外药物浓度相关.

  17. EMERGING CONTAMINANTS IN THE WATER CYCLE: FATE AND TRANSPORT

    Science.gov (United States)

    In the past decade, the scientific community and general public have become increasingly aware of the potential for the presence of unregulated, and generally unmonitored contaminants, found at low concentrations in surface, ground and drinking water. The most common pathway for...

  18. Chapter 2: Properties, sources, global fate and transport

    OpenAIRE

    Bidleman, Terry; Kurt-Karakus, Perihan; Armitage, James; Brown, Tanya; Danon Schaffer, Monica; Helm, Paul; Hung, Haley; Jantunen, Liisa; Kylin, Henrik; Li, Yi-Fan; Loock, Daniela; Luttmer, Carol; Ma, Jianmin; Macdonald, Robie; Mackay, Don

    2013-01-01

    Part II of the second Canadian Arctic Contaminants Assessment Report (CACAR-II) began with a section on “Physicochemical Properties of Persistent Organic Pollutants”, which identified key physicochemical (pchem) properties, provided the rationale for their measurement or prediction and tabulated literature citations for chemicals that are of concern to the NCP (Bidleman et al. 2003). The section also discussed temperature dependence of pchem properties and their applications to describing par...

  19. Plant Transporter Identification

    DEFF Research Database (Denmark)

    Larsen, Bo

    Membrane transport proteins (transporters) play a critical role for numerous biological processes, by controlling the movements of ions and molecules in and out of cells. In plants, transporters thus function as gatekeepers between the plant and its surrounding environment and between organs......, tissues, cells and intracellular compartments. Since plants are highly compartmentalized organisms with complex transportation infrastructures, they consequently have many transporters. However, the vast majority of predicted transporters have not yet been experimentally verified to have transport...... activity. This project contains a review of the implemented methods, which have led to plant transporter identification, and present our progress on creating a high-throughput functional genomics transporter identification platform....

  20. Fate of antibiotics during municipal water recycling treatment processes.

    Science.gov (United States)

    Le-Minh, N; Khan, S J; Drewes, J E; Stuetz, R M

    2010-08-01

    Municipal water recycling processes are potential human and environmental exposure routes for low concentrations of persistent antibiotics. While the implications of such exposure scenarios are unknown, concerns have been raised regarding the possibility that continuous discharge of antibiotics to the environment may facilitate the development or proliferation of resistant strains of bacteria. As potable and non-potable water recycling schemes are continuously developed, it is imperative to improve our understanding of the fate of antibiotics during conventional and advanced wastewater treatment processes leading to high-quality water reclamation. This review collates existing knowledge with the aim of providing new insight to the influence of a wide range of treatment processes to the ultimate fate of antibiotics during conventional and advanced wastewater treatment. Although conventional biological wastewater treatment processes are effective for the removal of some antibiotics, many have been reported to occur at 10-1000 ng L(-1) concentrations in secondary treated effluents. These include beta-lactams, sulfonamides, trimethoprim, macrolides, fluoroquinolones, and tetracyclines. Tertiary and advanced treatment processes may be required to fully manage environmental and human exposure to these contaminants in water recycling schemes. The effectiveness of a range of processes including tertiary media filtration, ozonation, chlorination, UV irradiation, activated carbon adsorption, and NF/RO filtration has been reviewed and, where possible, semi-quantitative estimations of antibiotics removals have been provided.

  1. Biological evaluation of a technetium-99m-labeled integrated tropane-BAT and its piperidine congener as potential dopamine transporter imaging agents

    Energy Technology Data Exchange (ETDEWEB)

    Kieffer, Davy M. [Laboratory of Radiopharmaceutical Chemistry, University of Leuven, UZ Gasthuisberg, B-3000 Leuven (Belgium); Vanbilloen, Hubert P. [Radiopharmacy, UZ Gasthuisberg, B-3000 Leuven (Belgium); Cleynhens, Bernard J. [Radiopharmacy, UZ Gasthuisberg, B-3000 Leuven (Belgium); Terwinghe, Christelle Y. [Radiopharmacy, UZ Gasthuisberg, B-3000 Leuven (Belgium); Mortelmans, Luc [Nuclear Medicine, UZ Gasthuisberg, B-3000 Leuven (Belgium); Bormans, Guy M. [Laboratory of Radiopharmaceutical Chemistry, University of Leuven, UZ Gasthuisberg, B-3000 Leuven (Belgium); Verbruggen, Alfons M. [Laboratory of Radiopharmaceutical Chemistry, University of Leuven, UZ Gasthuisberg, B-3000 Leuven (Belgium)]. E-mail: alfons.verbruggen@uz.kuleuven.ac.be

    2006-01-15

    Introduction: Recently, we have reported modification of {sup 99m}Tc-TRODAT-1 by integrating the N2S2 metal chelating unit and the tropane skeleton. Results of a preliminary biodistribution study in rats were promising with respect to brain uptake. The present report deals with the further biological characterization of the {sup 99m}Tc-labelled integrated TRODAT derivatives ({sup 99m}Tc-TropaBAT and {sup 99m}Tc-norchloro-TropaBAT) and with the synthesis and biological evaluation of a novel {sup 99m}Tc-labelled piperidine-based derivative ({sup 99m}Tc-PipBAT). Methods: Biodistribution of all radiolabelled complexes was studied in normal mice. A more detailed ex vivo intracerebral distribution study of the two {sup 99m}Tc-TropaBAT complexes was additionally performed in normal rats. Autoradiography of brain sections of normal mice (with or without pretreatment with FP-{beta}-CIT or haloperidol) and rats was performed. Affinity for the dopamine transporter (DAT) was also assessed in vitro in the presence or absence of cocaine. Results: Both {sup 99m}Tc-TropaBAT complexes show a slightly higher brain uptake than {sup 99m}Tc-TRODAT-1, but the striatum/cerebellum activity ratio is less favourable. Nevertheless, significant striatal uptake was detected after ex vivo autoradiography, but this uptake was also observed after pretreatment with FP-{beta}-CIT. Unexpectedly, no striatal uptake was detected after in vitro incubation of mouse brain sections with the tracer agents. For {sup 99m}Tc-PipBAT, neither brain uptake nor in vitro striatal uptake was found. Conclusion: Both {sup 99m}Tc-TropaBAT complexes exhibit similar diffusion into brain as {sup 99m}Tc-TRODAT-1, and ex vivo autoradiography shows significant striatal uptake. However, the inferior striatum/cerebellum activity ratio, the striatal uptake in mice pretreated with FP-{beta}-CIT or haloperidol, and the lack of striatal uptake during in vitro incubation prove that the DAT is not targeted. Brain uptake disappears

  2. Fate of Pyrethroids in Farmland Ponds

    DEFF Research Database (Denmark)

    Mogensen, B. B.; Sørensen, P. B.; Stuer-Lauridsen, F.;

    Pyrethroids constitute a group of widely used insecticides, which are toxic to aquatic organisms. This report presents the results from a 2-year study of the fate of pyrethroids in ponds, i.e. their distribution in the water column, the sediment and the surface microlayer respectively. The measur......Pyrethroids constitute a group of widely used insecticides, which are toxic to aquatic organisms. This report presents the results from a 2-year study of the fate of pyrethroids in ponds, i.e. their distribution in the water column, the sediment and the surface microlayer respectively...

  3. On the Formation of Tess’ Tragic Fate

    Institute of Scientific and Technical Information of China (English)

    张颖

    2014-01-01

    "Tess of the d’Urbervilles"is one of the most important books of Thomas Hardy.The heroine Tess is the most outstanding female image created by Hardy and also an idealized artistic model.Her fate moves the readers deeply and represents the beauty of the book.By analysing the special social conditions,we can see the typicalness and the inevitability of Tess’tragic fate.Tess naturally becomes the typical victim of the cruel social reality.Hardy’s realistic thought about the society and his progressive ideas to which oughts to be paid attention by us embodies in the novel.

  4. Quantifying intrinsic and extrinsic control of single-cell fates in cancer and stem/progenitor cell pedigrees with competing risks analysis.

    Science.gov (United States)

    Cornwell, J A; Hallett, R M; der Mauer, S Auf; Motazedian, A; Schroeder, T; Draper, J S; Harvey, R P; Nordon, R E

    2016-01-01

    The molecular control of cell fate and behaviour is a central theme in biology. Inherent heterogeneity within cell populations requires that control of cell fate is studied at the single-cell level. Time-lapse imaging and single-cell tracking are powerful technologies for acquiring cell lifetime data, allowing quantification of how cell-intrinsic and extrinsic factors control single-cell fates over time. However, cell lifetime data contain complex features. Competing cell fates, censoring, and the possible inter-dependence of competing fates, currently present challenges to modelling cell lifetime data. Thus far such features are largely ignored, resulting in loss of data and introducing a source of bias. Here we show that competing risks and concordance statistics, previously applied to clinical data and the study of genetic influences on life events in twins, respectively, can be used to quantify intrinsic and extrinsic control of single-cell fates. Using these statistics we demonstrate that 1) breast cancer cell fate after chemotherapy is dependent on p53 genotype; 2) granulocyte macrophage progenitors and their differentiated progeny have concordant fates; and 3) cytokines promote self-renewal of cardiac mesenchymal stem cells by symmetric divisions. Therefore, competing risks and concordance statistics provide a robust and unbiased approach for evaluating hypotheses at the single-cell level. PMID:27250534

  5. Control of Cell Fate in the Circulatory and Ventilatory Systems

    CERN Document Server

    Thiriet, Marc

    2012-01-01

    The volumes in this authoritative series present a multidisciplinary approach to modeling and simulation of flows in the cardiovascular and ventilatory systems, especially multiscale modeling and coupled simulations. The cardiovascular and respiratory systems are tightly coupled, as their primary function is to supply oxygen to and remove carbon dioxide from the body's cells. Because physiological conduits have deformable and reactive walls, macroscopic flow behavior and prediction must be coupled to nano- and microscopic events in a corrector scheme of regulated mechanisms. Therefore, investigation of flows of blood and air in physiological conduits requires an understanding of the biology, chemistry, and physics of these systems together with the mathematical tools to describe their functioning. Volumes 1 and 2 are devoted to cell organization and fate, as well as activities that are autoregulated and/or controlled by the cell environment. Volume 1 examined cellular features that allow adaptation to env...

  6. Organoarsenicals in poultry litter: detection, fate, and toxicity.

    Science.gov (United States)

    P Mangalgiri, Kiranmayi; Adak, Asok; Blaney, Lee

    2015-02-01

    Arsenic contamination in groundwater has endangered the health and safety of millions of people around the world. One less studied mechanism for arsenic introduction into the environment is the use of organoarsenicals in animal feed. Four organoarsenicals are commonly employed as feed additives: arsanilic acid, carbarsone, nitarsone, and roxarsone. Organoarsenicals are composed of a phenylarsonic acid molecule with substituted functional groups. This review documents the use of organoarsenicals in the poultry industry, reports analytical methods available for quantifying organic arsenic, discusses the fate and transport of organoarsenicals in environmental systems, and identifies toxicological concerns associated with these chemicals. In reviewing the literature on organoarsenicals, several research needs were highlighted: advanced analytical instrumentation that allows for identification and quantification of organoarsenical degradation products; a greater research emphasis on arsanilic acid, carbarsone, and nitarsone; identification of degradation pathways, products, and kinetics; and testing/development of agricultural wastewater and solid treatment technologies for organoarsenical-laden waste. PMID:25461415

  7. Medicinal Water? The occurrence and fate of pharmaceuticals in aquatic environments A short communication

    OpenAIRE

    Ricardo Sánchez-Murillo

    2016-01-01

    Although very little is known about the transport, fate and toxic effects of medical compounds in aquatic environments, the presence of these compounds in potable water sources can no longer be overlooked. We can argue that trace concentrations of drugs in the water is relatively a minor problem, however, the current and future demands on global potable freshwater supplies will probably lead to greater incidents of indirect and direct water-reuse situations at the local, regional, and cr...

  8. Use of column experiments to investigate the fate of organic micropollutants – a review

    OpenAIRE

    Banzhaf, Stefan; Hebig, Klaus H.

    2016-01-01

    Although column experiments are frequently used to investigate the transport of organic micropollutants, little guidance is available on what they can be used for, how they should be set up, and how the experiments should be carried out. This review covers the use of column experiments to investigate the fate of organic micropollutants. Alternative setups are discussed together with their respective advantages and limitations. An overview is presented of published column experiments investiga...

  9. Modelling the fate of organic micropollutants in stormwater ponds

    DEFF Research Database (Denmark)

    Vezzaro, Luca; Eriksson, Eva; Ledin, Anna;

    2011-01-01

    models. The fate of four different MP in a stormwater retention pond was simulated by applying two steady-state multimedia fate models (EPI Suite and SimpleBox) commonly applied in chemical risk assessment and a dynamic multimedia fate model (Stormwater Treatment Unit Model for Micro Pollutants — STUMP...

  10. Septic systems as hot-spots of pollutants in the environment: Fate and mass balance of micropollutants in septic drainfields

    Science.gov (United States)

    Effluent discharged from septic systems, also known as onsite wastewater treatment systems, can be an important source of micropollutants in the environment. We investigated the fate and transport of 17 micropollutants, including human excretion markers, hormones, pharmaceuticals and personal care p...

  11. SIMPLEBOX: a generic multimedia fate evaluation model

    NARCIS (Netherlands)

    van de Meent D

    1993-01-01

    This document describes the technical details of the multimedia fate model SimpleBox, version 1.0 (930801). SimpleBox is a multimedia box model of what is commonly referred to as a "Mackay-type" model ; it assumes spatially homogeneous environmental compartments (air, water, suspended m

  12. Remote sensing for water quality and biological measurements in coastal waters

    Science.gov (United States)

    Johnson, R. W.; Harriss, R. C.

    1980-01-01

    Recent remote sensing experiments in the United States' coastal waters indicate that certain biological and water quality parameters have distinctive spectral characteristics. Data outputs from remote sensors, to date, include: (1) high resolution measurements to determine concentrations and distributions of total suspended particulates, temperature, salinity, chlorophyll a, and phytoplankton color group associations from airborne and/or satellite platforms, and (2) low resolution measurements of total suspended solids, temperature, ocean color, and possibly chlorophyll from satellite platforms. A summary of platforms, sensors and parameters measured is given. Remote sensing, especially when combined with conventional oceanographic research methods, can be useful in such high priority research areas as estuarine and continental shelf sediment transport dynamics, transport and fate of marine pollutants, marine phytoplankton dynamics, and ocean fronts.

  13. Remote sensing for water quality and biological measurements in coastal waters

    International Nuclear Information System (INIS)

    Recent remote sensing experiments in the United States' coastal waters indicate that certain biological and water quality parameters have distinctive spectral characteristics. Data outputs from remote sensors, to date, include: (1) high resolution measurements to determine concentrations and distributions of total suspended particulates, temperature, salinity, chlorophyll a, and phytoplankton color group associations from airborne and/or satellite platforms, and (2) low resolution measurements of total suspended solids, temperature, ocean color, and possibly chlorophyll from satellite platforms. A summary of platforms, sensors and parameters measured is given. Remote sensing, especially when combined with conventional oceanographic research methods, can be useful in such high priority research areas as estuarine and continental shelf sediment transport dynamics, transport and fate of marine pollutants, marine phytoplankton dynamics, and ocean fronts

  14. Occurrence, fate, behavior and ecotoxicological state of phthalates in different environmental matrices.

    Science.gov (United States)

    Net, Sopheak; Sempéré, Richard; Delmont, Anne; Paluselli, Andrea; Ouddane, Baghdad

    2015-04-01

    Because of their large and widespread application, phthalates or phthalic acid esters (PAEs) are ubiquitous in all the environmental compartements. They have been widely detected throughout the worldwide environment. Indoor air where people spend 65-90% of their time is also highly contaminated by various PAEs released from plastics, consumer products as well as ambient suspended particulate matter. Because of their widespread application, PAEs are the most common chemicals that humans are in contact with daily. Based on various exposure mechanisms, including the ingestion of food, drinking water, dust/soil, air inhalation and dermal exposure the daily intake of PAEs may reach values as high as 70 μg/kg/day. PAEs are involved in endocrine disrupting effects, namely, upon reproductive physiology in different species of fish and mammals. They also present a variety of additional toxic effects for many other species including terrestrial and aquatic fauna and flora. Therefore, their presence in the environment has attracted considerable attention due to their potential impacts on ecosystem functioning and on public health. This paper is a synthesis of the extensive literature data on behavior, transport, fate and ecotoxicological state of PAEs in environmental matrices: air, water, sediment, sludge, wastewater, soil, and biota. First, the origins and physicochemical properties of PAEs that control the behavior, transport and fate in the environment are reviewed. Second, the compilation of data on transport and fate, adverse environmental and human health effects, legislation, restrictions, and ecotoxicological state of the environment based on PAEs is presented. PMID:25730609

  15. Occurrence, fate, behavior and ecotoxicological state of phthalates in different environmental matrices.

    Science.gov (United States)

    Net, Sopheak; Sempéré, Richard; Delmont, Anne; Paluselli, Andrea; Ouddane, Baghdad

    2015-04-01

    Because of their large and widespread application, phthalates or phthalic acid esters (PAEs) are ubiquitous in all the environmental compartements. They have been widely detected throughout the worldwide environment. Indoor air where people spend 65-90% of their time is also highly contaminated by various PAEs released from plastics, consumer products as well as ambient suspended particulate matter. Because of their widespread application, PAEs are the most common chemicals that humans are in contact with daily. Based on various exposure mechanisms, including the ingestion of food, drinking water, dust/soil, air inhalation and dermal exposure the daily intake of PAEs may reach values as high as 70 μg/kg/day. PAEs are involved in endocrine disrupting effects, namely, upon reproductive physiology in different species of fish and mammals. They also present a variety of additional toxic effects for many other species including terrestrial and aquatic fauna and flora. Therefore, their presence in the environment has attracted considerable attention due to their potential impacts on ecosystem functioning and on public health. This paper is a synthesis of the extensive literature data on behavior, transport, fate and ecotoxicological state of PAEs in environmental matrices: air, water, sediment, sludge, wastewater, soil, and biota. First, the origins and physicochemical properties of PAEs that control the behavior, transport and fate in the environment are reviewed. Second, the compilation of data on transport and fate, adverse environmental and human health effects, legislation, restrictions, and ecotoxicological state of the environment based on PAEs is presented.

  16. Apical versus Basal Neurogenesis Directs Cortical Interneuron Subclass Fate

    Directory of Open Access Journals (Sweden)

    Timothy J. Petros

    2015-11-01

    Full Text Available Fate determination in the mammalian telencephalon, with its diversity of neuronal subtypes and relevance to neuropsychiatric disease, remains a critical area of study in neuroscience. Most studies investigating this topic focus on the diversity of neural progenitors within spatial and temporal domains along the lateral ventricles. Often overlooked is whether the location of neurogenesis within a fate-restricted domain is associated with, or instructive for, distinct neuronal fates. Here, we use in vivo fate mapping and the manipulation of neurogenic location to demonstrate that apical versus basal neurogenesis influences the fate determination of major subgroups of cortical interneurons derived from the subcortical telencephalon. Somatostatin-expressing interneurons arise mainly from apical divisions along the ventricular surface, whereas parvalbumin-expressing interneurons originate predominantly from basal divisions in the subventricular zone. As manipulations that shift neurogenic location alter interneuron subclass fate, these results add an additional dimension to the spatial-temporal determinants of neuronal fate determination.

  17. The Fate of Intracluster Radio Plasma

    OpenAIRE

    Ensslin, Torsten A.

    2002-01-01

    Radio plasma injected by active radio galaxies into clusters of galaxies quickly becomes invisible due to radiative losses of the relativistic electrons. In this talk, the fate of radio plasma and its role for the galaxy cluster is discussed: buoyancy removes it from the central regions and allows to transfer its energy into the ambient gas. The remaining low energy electron populations are still able to emit a low luminosity glow of observable radiation via synchrotron-self Comptonized emiss...

  18. Chemical Dissolution Pathways of MoS2 Nanosheets in Biological and Environmental Media.

    Science.gov (United States)

    Wang, Zhongying; von dem Bussche, Annette; Qiu, Yang; Valentin, Thomas M; Gion, Kyle; Kane, Agnes B; Hurt, Robert H

    2016-07-01

    Material stability and dissolution in aqueous media are key issues to address in the development of a new nanomaterial intended for technological application. Dissolution phenomena affect biological and environmental persistence; fate, transport, and biokinetics; device and product stability; and toxicity pathways and mechanisms. This article shows that MoS2 nanosheets are thermodynamically and kinetically unstable to O2-oxidation under ambient conditions in a variety of aqueous media. The oxidation is accompanied by nanosheet degradation and release of soluble molybdenum and sulfur species, and generates protons that can colloidally destabilize the remaining sheets. The oxidation kinetics are pH-dependent, and a kinetic law is developed for use in biokinetic and environmental fate modeling. MoS2 nanosheets fabricated by chemical exfoliation with n-butyl-lithium are a mixture of 1T (primary) and 2H (secondary) phases and oxidize rapidly with a typical half-life of 1-30 days. Ultrasonically exfoliated sheets are in pure 2H phase, and oxidize much more slowly. Cytotoxicity experiments on MoS2 nanosheets and molybdate ion controls reveal the relative roles of the nanosheet and soluble fractions in the biological response. These results indicate that MoS2 nanosheets will not show long-term persistence in living systems and oxic natural waters, with important implications for biomedical applications and environmental risk. PMID:27267956

  19. Fate and effects of acrolein.

    Science.gov (United States)

    Ghilarducci, D P; Tjeerdema, R S

    1995-01-01

    ). Acrolein is highly reactive, and intercompartmental transport is limited. However, it is eliminated from aqueous environments by volatilization and hydration to beta-hydroxypropanal, after which biotransformation occurs, with a half-life of 7-10 d. The Koc for acrolein is 24, and it is not likely to be retained in soil; activated carbon adsorbs only 30% from solution. Thus, the aldehyde is either leached extensively in moist soil or volatilizes quickly from dry soil. It is eliminated from air by reaction with .OH (half-life, 0.5-1.2 d), NOx (half-life, 16 d), and O3 (half-life, 59 d), as well as by photolysis and wet deposition. As expected from its high water solubility, bioaccumulation is low. Acrolein is highly toxic by all routes of exposure. The respiratory system is the most common target: exposure causes localized irritation, respiratory distress, pulmonary edema, cellular necrosis, and increased susceptibility to microbial diseases. Additionally, acute inhalation studies verify that it is a severe respiratory irritant that affects respiratory rates. Respiratory rate depression may have a protective effect by minimizing vapor inhalation, thereby explaining the subadditive effect of acrolein when combined with the other toxic combustion by-products CO and HCHO. Liquid contact with the skin and eyes causes severe irritation, opaque or cloudy corneas, and localized epidermal necrosis, but no allergic contact dermatitis. The cardiovascular system is affected, resulting in increased blood pressure, platelet aggregation, and quick cessation of beating in perfused rat hearts. It may also inhibit mitochondrial oxidative phosphorylation in the myocardium. Acute LD50s and LC50s are low. Levels are 7-46 mg/kg and 18-750 mg/m3, respectively, in rats; aquatic organisms are affected above 11.4 micrograms/L.(ABSTRACT TRUNCATED) PMID:8599034

  20. Transporte de NO3- e NH4+ em agregados de Latossolo Vermelho com e sem atividade biológica NO3- and NH4+ transport in a typic Haplortox aggregates with and without biological activity

    Directory of Open Access Journals (Sweden)

    Fábio C. Coelho

    2007-08-01

    Full Text Available Objetivou-se, com este trabalho, avaliar a influência do tamanho dos agregados de um Latossolo Vermelho distrófico sobre as transformações e transporte do amônio e do nitrato em condições de presença e ausência de atividade biológica. Utilizou-se o fatorial 2³ x 4, com fatores e níveis: vegetação de cobertura do solo (cerrado e milho ; atividade biológica (com e sem esterilização do solo; fontes de N da solução com 10 mimol L-1 de N, para saturação das colunas (Ca(NO32 e NH4CI e classes de agregados (2,0 a 1,0; 1,0 a 0,5; 0,5 a 0,25 e 0,25 a 0,105 mm. Na primeira eluição, o efluente das colunas contendo microbiota ativa e saturação com Ca(NO32 apresentou teor de NO3- menor no efluente dos agregados de 0,25 a 0,105 mm; já em condições de esterilização, ocorreu o inverso: maior concentração do NO3- no efluente dos agregados de 0,25 a 0,105 mm. Para as colunas saturadas com NH4CI, na primeira eluição os teores do NH4+ foram maiores nos efluentes dos agregados de 0,25 a 0,105 mm para todas as combinações de cobertura de solo e esterilização, enquanto na presença da microbiota ativa o efluente dos agregados de 0,25 a 0,105 mm apresentou teor semelhante ao dos agregados de 0,5 a 0,25 mm.A laboratory experiment was carried out in a randomized block design with three replications, in which columns with aggregate classes 2.0-1.0; 1.0-0,5; 0.5-0.25 and 0.25-0.105 mm of a typic Haplortox were used. The treatments corresponded to a 2³ x 4 factorial, with soil covering vegetation (savannah and maize; biological activity (with and without soil sterilization with methyl bromide; sources of N with 10 mumol L-1 of N for saturation of the columns (Ca(NO32 and NH4CI; and aggregate classes (2.0-1.0; 1.0-0.5; 0.5-0.25 and 0.25-0.105 mm. After seven days of incubation of the columns with aggregates at maximum water retention, percolations were made with water, after two days under saturated condition, totaling six samples (0, 2

  1. JAK/STAT signaling regulates tissue outgrowth and male germline stem cell fate in Drosophila

    Institute of Scientific and Technical Information of China (English)

    Shree Ram SINGH; Xiu CHEN; Steven X.HOU

    2005-01-01

    In multicellular organisms, biological activities are regulated by cell signaling. The various signal transduction pathways regulate cell fate, proliferation, migration, and polarity. Miscoordination of the communicative signals will lead to disasters like cancer and other fatal diseases. The JAK/STAT signal transduction pathway is one of the pathways, which was first identified in vertebrates and is highly conserved throughout evolution. Studying the JAK/STAT signal transduction pathway in Drosophila provides an excellent opportunity to understand the molecular mechanism of the cell regulation during development and tumor formation. In this review, we discuss the general overview of JAK/STAT signaling in Drosophila with respect to its functions in the eye development and stem cell fate determination.

  2. Interrogating cellular fate decisions with high-throughput arrays of multiplexed cellular communities.

    Science.gov (United States)

    Chen, Sisi; Bremer, Andrew W; Scheideler, Olivia J; Na, Yun Suk; Todhunter, Michael E; Hsiao, Sonny; Bomdica, Prithvi R; Maharbiz, Michel M; Gartner, Zev J; Schaffer, David V

    2016-01-01

    Recreating heterotypic cell-cell interactions in vitro is key to dissecting the role of cellular communication during a variety of biological processes. This is especially relevant for stem cell niches, where neighbouring cells provide instructive inputs that govern cell fate decisions. To investigate the logic and dynamics of cell-cell signalling networks, we prepared heterotypic cell-cell interaction arrays using DNA-programmed adhesion. Our platform specifies the number and initial position of up to four distinct cell types within each array and offers tunable control over cell-contact time during long-term culture. Here, we use the platform to study the dynamics of single adult neural stem cell fate decisions in response to competing juxtacrine signals. Our results suggest a potential signalling hierarchy between Delta-like 1 and ephrin-B2 ligands, as neural stem cells adopt the Delta-like 1 phenotype of stem cell maintenance on simultaneous presentation of both signals. PMID:26754526

  3. Evaluation of terrestrial microcosms for detection, fate, and survival analysis of genetically engineered microorganisms and their recombinant genetic material

    Energy Technology Data Exchange (ETDEWEB)

    Fredrickson, J.K.; Seidler, R.J.

    1989-02-01

    The research included in this document represents the current scientific information available regarding the applicability of terrestrial microcosms and related methodologies for evaluating detection methods and the fate and survival of microorganisms in the environment. The three terrestrial microcosms described in this document were used to evaluate the survival and fate of recombinant bacteria in soils and in association with plant surfaces and insects and their transport through soil with percolating water and root systems, and to test new methods and procedures to improve detection and enumeration of bacteria in soil. Simple (potting soil composed of peat mix and perlite, lacking environmental control and monitoring) and complex microcosms (agricultural soil with partial control and monitoring of environmental conditions) were demonstrated to be useful tools for preliminary assessments of microbial viability in terrestrial ecosystems. These studies evaluated the survival patterns of Enterobacter cloacae (pBR322) in soil and on plant surfaces and the ingestion of this same microorganism by cutworms and survival in the foregut and frass. The Versacore microcosm design was used to monitor the fate and competitiveness of genetically engineered bacteria in soil. Both selective media and gene probes were used successfully to follow the fate of two recombinant Pseudomonas sp. introduced into Versacore microcosms. Intact soil-core microcosms were employed to evaluate the fate and transport of genetically altered Azospirillum sp. and Pseudomonas sp. in soil and the plant rhizosphere. The usefulness of these various microcosms as a tool for risk assessment is underscored by the ease in obtaining soil from a proposed field release site to evaluate subsequent GEM fate and survival.

  4. Effects of bioturbation on the fate of oil in coastal sandy sediments - An in situ experiment

    DEFF Research Database (Denmark)

    Timmermann, Karen; Banta, Gary T.; Klinge, Lars;

    2011-01-01

    Effects of bioturbation by the common lugworm Arenicola marina on the fate of oil hydrocarbons (alkanes and PAHs) were studied in situ during a simulated oil spill in a shallow coastal area of Roskilde fjord, Denmark. The fate of selected oil compounds was monitored during 120 d using GC......–MS and bioturbation activity (feces production and irrigation) was measured regularly during the experiment and used as input parameters in a mechanistic model describing the effects of A. marina on the transport and degradation of oil compounds in the sediment. The chemical analytical data and model results...... indicated that A. marina had profound and predictable effects on the distribution, degradation and preservation of oil and that the net effect depended on the initial distribution of oil. In sediment with an oil contaminated subsurface-layer A. marina buried the layer deeper in the sediment which clearly...

  5. The role of the global cryosphere in the fate of organic contaminants

    Directory of Open Access Journals (Sweden)

    A. M. Grannas

    2013-03-01

    Full Text Available The cryosphere is an important component of global organic contaminant cycles. Snow is an efficient scavenger of atmospheric organic pollutants while a seasonal snowpack, sea ice, glaciers and ice caps are contaminant reservoirs on time scales ranging from days to millennia. Important physical and chemical processes occurring in the various cryospheric compartments impact contaminant cycling and fate. A variety of interactions and feedbacks also occur within the cryospheric system, most of which are susceptible to perturbations due to climate change. In this article, we review the current state of knowledge regarding the transport and processing of organic contaminants in the global cryosphere with an emphasis on the role of a changing climate. Given the complexity of contaminant interactions with the cryosphere and limitations on resources and research capacity, interdisciplinary research and extended collaborations are essential to close identified knowledge gaps and to improve our understanding of contaminant fate under a changing climate.

  6. Fate, behavior, and bioavailability of metal and metal oxide nanomaterials in terrestrial ecosystems

    Science.gov (United States)

    Bertsch, P. M.; Unrine, J. M.; Judy, J.; Tsyusko, O.

    2012-12-01

    Despite the benefits that are currently being manifested and those transformative breakthroughs that will undoubtedly result from advances in nanotechnology, concerns surrounding the potential negative impacts to the environment and human health and welfare continue to emerge. Information on the transport and fate of manufactured nanomaterials (MNMs) in the environment and on their potential effects to human and ecological receptors is emerging at an increasing rate. Notwithstanding these developments, the research enterprise focused on the environmental implications of nanotechnology is in its infancy and few unifying principles have yet to emerge. This lack of unanimity is related to many factors including, the vast diversity in chemical composition, size, shape, and surface chemical properties of MNMs, as well as the range of receptor species and cell lines investigated. Additionally, the large variation in exposure methodologies employed by various investigators as well as the discrepancies in the amount and quality of characterization data collected to support specific conclusions, provide major challenges for developing unifying concepts and principles. As the utilization of MNMs for a large variety of applications is currently in an exponential growth phase, there is great urgency to develop information that can be used to identify priority areas for assessing risks to humans and the environment, as well as in developing potential mitigation strategies. We have been investigating the fate, behavior, and potential impacts of MNMs released into terrestrial ecosystems by examining the bioavailability and toxicity as well as the trophic transfer of a range of metal and metal oxide nanoparticles (Ag, Au, Cu, TiO2, ZnO, CeO2) to microorganisms, detritivores, and plants. Interdisciplinary studies include the characterization of the nanoparticles and aged nanoparticles in complex media, the distribution of nanoparticles in biological tissues, nanoparticle toxicity

  7. Transport and transformation of genetic information in the critical zone: The case of antibiotic resistance genes

    Science.gov (United States)

    Zhu, Y. G.

    2015-12-01

    In addition to material and energy flows, the dynamics and functions of the Earth's critical zone are intensively mediated by biological actions performed by diverse organisms. These biological actions are modulated by the expression of functional genes and their translation into enzymes that catalyze geochemical reactions, such as nutrient turnover and pollutant biodegradation. Although geobiology, as an interdisciplinary research area, is playing and vital role in linking biological and geochemical processes at different temporal and spatial scales, the distribution and transport of functional genes have rarely been investigated from the Earth's critical zone perspectives. To illustrate the framework of studies on the transport and transformation of genetic information in the critical zone, antibiotic resistance is taken as an example. Antibiotic resistance genes are considered as a group of emerging contaminants, and their emergence and spread within the critical zone on one hand are induced by anthropogenic activities, and on other hand are threatening human health worldwide. The transport and transformation of antibiotic resistance genes are controlled by both horizontal gene transfer between bacterial cells and the movement of bacteria harboring antibiotic resistance genes. In this paper, the fate and behavior of antibiotic resistance genes will be discussed in the following aspects: 1) general overview of environmental antibiotic resistance; 2) high through quantification of the resistome in various environmental media; 3) pathways of resistance gene flow within the critical zone; and 4) potential strategies in mitigating antibiotic resistance, particularly from the critical zone perspectives.

  8. Applications of contaminant fate and bioaccumulation models in assessing ecological risks of chemicals: A case study for gasoline hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    MacLeod, Matthew; McKone, Thomas E.; Foster, Karen L.; Maddalena, Randy L.; Parkerton, Thomas F.; Mackay, Don

    2004-02-01

    Mass balance models of chemical fate and transport can be applied in ecological risk assessments for quantitative estimation of concentrations in air, water, soil and sediment. These concentrations can, in turn, be used to estimate organism exposures and ultimately internal tissue concentrations that can be compared to mode-of-action-based critical body residues that correspond to toxic effects. From this comparison, risks to the exposed organism can be evaluated. To illustrate the practical utility of fate models in ecological risk assessments of commercial products, the EQC model and a simple screening level biouptake model including three organisms, (a bird, a mammal and a fish) is applied to gasoline. In this analysis, gasoline is divided into 24 components or ''blocks'' with similar environmental fate properties that are assumed to elicit ecotoxicity via a narcotic mode of action. Results demonstrate that differences in chemical properties and mode of entry into the environment lead to profound differences in the efficiency of transport from emission to target biota. We discuss the implications of these results and insights gained into the regional fate and ecological risks associated with gasoline. This approach is particularly suitable for assessing mixtures of components that have similar modes of action. We conclude that the model-based methodologies presented are widely applicable for screening level ecological risk assessments that support effective chemicals management.

  9. Using gridded multimedia model to simulate spatial fate of Benzo[α]pyrene on regional scale.

    Science.gov (United States)

    Liu, Shijie; Lu, Yonglong; Wang, Tieyu; Xie, Shuangwei; Jones, Kevin C; Sweetman, Andrew J

    2014-02-01

    Predicting the environmental multimedia fate is an essential step in the process of assessing the human exposure and health impacts of chemicals released into the environment. Multimedia fate models have been widely applied to calculate the fate and distribution of chemicals in the environment, which can serve as input to a human exposure model. In this study, a grid based multimedia fugacity model at regional scale was developed together with a case study modeling the fate and transfer of Benzo[α]pyrene (BaP) in Bohai coastal region, China. Based on the estimated emission and in-site survey in 2008, the BaP concentrations in air, vegetation, soil, fresh water, fresh water sediment and coastal water as well as the transfer fluxes were derived under the steady-state assumption. The model results were validated through comparison between the measured and modeled concentrations of BaP. The model results indicated that the predicted concentrations of BaP in air, fresh water, soil and sediment generally agreed with field observations. Model predictions suggest that soil was the dominant sink of BaP in terrestrial systems. Flow from air to soil, vegetation and costal water were three major pathways of BaP inter-media transport processes. Most of the BaP entering the sea was transferred by air flow, which was also the crucial driving force in the spatial distribution processes of BaP. The Yellow River, Liaohe River and Daliao River played an important role in the spatial transformation processes of BaP. Compared with advection outflow, degradation was more important in removal processes of BaP. Sensitivities of the model estimates to input parameters were tested. The result showed that emission rates, compartment dimensions, transport velocity and degradation rates of BaP were the most influential parameters for the model output. Monte Carlo simulation was carried out to determine parameter uncertainty, from which the coefficients of variation for the estimated Ba

  10. Mercury Contamination: Fate and Risk Minimization Strategies

    Science.gov (United States)

    Charlet, L.

    Two river basins have been studied in French Guyana, which are subject to heavy mercury contamination, due to illegal gold mining. Within the framework of an interdisciplinary European project, the fate of mercury in water, air, soil, sediment has been studied, as well as its bio-accumulation in the food chain. This bioaccumulation results in the contamination of amerindian populations, through fish consumption. This study has been done in close contact with the economic and political actors. The results of the scientific interdisciplinary study has been translated in terms of risk minimization strategies, which are analyzed in the framework of the European Water Framework Directive.

  11. Glucocorticoid dose determines osteocyte cell fate

    OpenAIRE

    Jia, Junjing; Yao, Wei; Guan, Min; Dai, WeiWei; Shahnazari, Mohammad; Kar, Rekha; Bonewald, Lynda; Jiang, Jean X.; Lane, Nancy E.

    2011-01-01

    In response to cellular insult, several pathways can be activated, including necrosis, apoptosis, and autophagy. Because glucocorticoids (GCs) have been shown to induce both osteocyte apoptosis and autophagy, we sought to determine whether osteocyte cell fate in the presence of GCs was dose dependent by performing in vivo and in vitro studies. Male Swiss-Webster mice were treated with slow-release prednisolone pellets at 1.4, 2.8, and 5.6 mg/kg/d for 28 d. An osteocyte cell line, MLO-Y4 cells...

  12. Microgravity Fluids for Biology, Workshop

    Science.gov (United States)

    Griffin, DeVon; Kohl, Fred; Massa, Gioia D.; Motil, Brian; Parsons-Wingerter, Patricia; Quincy, Charles; Sato, Kevin; Singh, Bhim; Smith, Jeffrey D.; Wheeler, Raymond M.

    2013-01-01

    Microgravity Fluids for Biology represents an intersection of biology and fluid physics that present exciting research challenges to the Space Life and Physical Sciences Division. Solving and managing the transport processes and fluid mechanics in physiological and biological systems and processes are essential for future space exploration and colonization of space by humans. Adequate understanding of the underlying fluid physics and transport mechanisms will provide new, necessary insights and technologies for analyzing and designing biological systems critical to NASAs mission. To enable this mission, the fluid physics discipline needs to work to enhance the understanding of the influence of gravity on the scales and types of fluids (i.e., non-Newtonian) important to biology and life sciences. In turn, biomimetic, bio-inspired and synthetic biology applications based on physiology and biology can enrich the fluid mechanics and transport phenomena capabilities of the microgravity fluid physics community.

  13. Design of Indium Arsenide nanowire sensors for pH and biological sensing and low temperature transport through p-doped Indium Arsenide nanowires

    DEFF Research Database (Denmark)

    Upadhyay, Shivendra

    With the goal of real time electrical detection of chemical and biological species, nanowires have shown great promise with high sensitivity due to their large surface to volume ratio. While the focus of such electrical detection has shifted to one dimensional semiconductor nanostuctures, Silicon...

  14. Structural Biology of The sequestration & Transport of Heavy Metal Toxins: NMR Structure Determination of Proteins Containing the CYS-X-Y-Metal Binding Motif

    Energy Technology Data Exchange (ETDEWEB)

    Stanley J. Opella

    2004-03-10

    The support from the Department of Energy enabled us to initiate research on several proteins from the bacterial mercury detoxification system; in particular, we were able to determine the structures of MerP and related metal binding sequences. We have also worked on the membrane transport proteins MerF and MerT.

  15. Development of Filter-Blower Unit for use in the Advanced Nuclear Biological Chemical Protection System (ANBCPS) Helicopter/Transport-aircraft version

    NARCIS (Netherlands)

    Sabel, R.; Reffeltrath, P.A.; Jonkman, A.; Post, T.

    2006-01-01

    As a participant in the three-nation partnership for development of the ANBCP-S for use in Helicopters, Transport Aircraft and Fast Jet, the Royal Netherlands Airforce (RNLAF) picked up the challenge to design a Filter- Blower-Unit (FBU). Major Command (MajCom) of the RNLAF set priority to develop a

  16. A role for tungsten in the biology of Campylobacter jejuni: tungstate stimulates formate dehydrogenase activity and is transported via an ultra-high affinity ABC system distinct from the molybdate transporter.

    Science.gov (United States)

    Smart, Jonathan P; Cliff, Matthew J; Kelly, David J

    2009-11-01

    The food-borne pathogen Campylobacter jejuni possesses no known tungstoenzymes, yet encodes two ABC transporters (Cj0300-0303 and Cj1538-1540) homologous to bacterial molybdate (ModABC) uptake systems and the tungstate transporter (TupABC) of Eubacterium acidaminophilum respectively. The actual substrates and physiological role of these transporters were investigated. Tryptophan fluorescence spectroscopy and isothermal titration calorimetry of the purified periplasmic binding proteins of each system revealed that while Cj0303 is unable to discriminate between molybdate and tungstate (K(D) values for both ligands of 4-8 nM), Cj1540 binds tungstate with a K(D) of 1.0 +/- 0.2 pM; 50 000-fold more tightly than molybdate. Induction-coupled plasma mass spectroscopy of single and double mutants showed that this large difference in affinity is reflected in a lower cellular tungsten content in a cj1540 (tupA) mutant compared with a cj0303c (modA) mutant. Surprisingly, formate dehydrogenase (FDH) activity was decreased approximately 50% in the tupA strain, and supplementation of the growth medium with tungstate significantly increased FDH activity in the wild type, while inhibiting known molybdoenzymes. Our data suggest that C. jejuni possesses a specific, ultra-high affinity tungstate transporter that supplies tungsten for incorporation into FDH. Furthermore, possession of two MoeA paralogues may explain the formation of both molybdopterin and tungstopterin in this bacterium. PMID:19818021

  17. Biological Threats

    Science.gov (United States)

    ... Workplace Plans School Emergency Plans Main Content Biological Threats Biological agents are organisms or toxins that can ... for Disease Control and Prevention . Before a Biological Threat Unlike an explosion, a biological attack may or ...

  18. Investigating Student Ideas About the Fate of the Universe

    Science.gov (United States)

    Conlon, Mallory; Coble, Kimberly A.; Bailey, Janelle M.; Cominsky, Lynn R.

    2015-01-01

    Data from recent surveys have enabled astronomers to precisely quantify the composition of the Universe, though the nature of its primary component, dark energy, remains a mystery. The evolution of dark energy and how it might impact the Universe in the future is an area of intense study. As astronomers further develop an understanding of the fate of the Universe, it is essential to study student ideas on this fate so that instructors can communicate the field's current status and its underpinnings more effectively to their students. In this study, we examine undergraduate students' pre-instruction ideas of the fate of the Universe in twelve semester-long courses at four institutions. We also examine ideas about the fate of the Universe as undergraduate students progress through an introductory or advanced astronomy course at two institutions. The data include pre-course surveys given during the first week of instruction [N=291], midterm and final exam questions [N=58], post-course surveys [N=26], and student interviews [N=7]. We find that, though the term was not necessarily used, students that respond tend to describe a 'big freeze' scenario in the pre-course surveys. Students mention the Universe's expansion when describing how we know the fate of the Universe but do not discuss how we know the Universe is expanding or the relationship between expansion and the fate of the Universe. We also find that students discuss the fate of the solar system or the galaxy in the pre-course surveys instead of the fate of the Universe, suggesting conflation of the Universe with the solar system or the galaxy. At the end of the course, we find that students continue to describe a 'big freeze' scenario and fail to explain how we determine the fate of the Universe. We also find that student tendency to discuss the fate of the solar system or galaxy instead of the fate of the Universe is diminished by the end of the course.

  19. Environmental Transformations of Engineered Nanoparticles: Implications for Nanoparticle Transport

    Science.gov (United States)

    Lowry, G. V.; Levard, C.; Reinsch, B.; Ma, R.; Kirschling, T.; Brown, G. E.; Tilton, R.

    2011-12-01

    Geochemical transformations that engineered nanomaterials (ENMs) may undergo in different environments very poorly characterized. Sulfidation of metallic nanoparticles (NPs), particularly class B soft metals such as Ag NPs, is expected in the environment. Transformation will alter the surface properties and fate of Ag NPs. ENMs are often coated with a polymeric coating to prevent aggregation or to provide specific functionality. These coatings dramatically impact their transport properties. The potential for biological processes to remove covalently bound polymeric coatings from nanoparticles, and the effect of coating loss on the particle's transport properties is not known. The objectives of this work were to 1) better understand the environmental conditions that would promote sufidation of class B soft metal nanoparticles (Ag NPs and ZnO NPs), and to determine the effect that this has on their surface properties and aggregation potential, and 2) to determine if microbes can access covalently bound polymeric coatings from an engineered NP, and the effect on their surface properties and aggregation potential. Ag and ZnO NPs were synthesized and characterized for size, shape, coating mass, charge, crystal structure, and chemical composition using a range of analytical methods (TEM, DLS, TGA, EPM, XAS). These particles were sulfidized in the laboratory, biosolids, and wetland soils and the transformed materials were characterized. Sulfidation was rapid in all cases and resulted in a mixed crystalline/amorphous Ag2S/Ag2O particle depending on the ratio of Ag to HS- in the system. Sulfidation decreased surface charge and displayed significant aggregation compared to the unsulfidized materials. Sulfidation also occurred in biosolids and in wetland soils. Polymer coatings covalently bound to ENMs are bioavailable. Model poly(ethylene oxide) (PEO) brush-coated nanoparticles (30 nm hydrodynamic radius) were synthesized to obtain a nanomaterial in which biodegradation was

  20. Fate of Silver Nanoparticles in Lake Mesocosms

    Science.gov (United States)

    Furtado, Lindsay

    The fate of silver nanoparticles (AgNPs) in surface waters determines the ecological risk of this emerging contaminant. In this research, the fate of AgNPs in lake mesocosms was studied using both a continuous (i.e. drip) and one-time (i.e. plug) dosing regime. AgNPs were persistent in the tested lake environment as there was accumulation in the water column over time in drip mesocosms and slow dissipation from the water column (half life of 20 days) in plug mesocosms. In drip mesocosms, AgNPs were found to accumulate in the water column, periphtyon, and sediment according to loading rate; and, AgNP coating (PVP vs. CT) had no effect on agglomeration and dissolution based on filtration analysis. In plug mesocosms, cloud point extraction (CPE), single-particle-inductively coupled mass spectroscopy (spICP-MS), and asymmetrical flow field-flow fractionation (AF4-ICP-MS) confirmed the temporal dissolution of AgNPs into Ag+ over time; however, complexation is expected to reduce the toxicity of Ag + in natural waters.

  1. Connecting Mitochondria, Metabolism, and Stem Cell Fate.

    Science.gov (United States)

    Wanet, Anaïs; Arnould, Thierry; Najimi, Mustapha; Renard, Patricia

    2015-09-01

    As sites of cellular respiration and energy production, mitochondria play a central role in cell metabolism. Cell differentiation is associated with an increase in mitochondrial content and activity and with a metabolic shift toward increased oxidative phosphorylation activity. The opposite occurs during reprogramming of somatic cells into induced pluripotent stem cells. Studies have provided evidence of mitochondrial and metabolic changes during the differentiation of both embryonic and somatic (or adult) stem cells (SSCs), such as hematopoietic stem cells, mesenchymal stem cells, and tissue-specific progenitor cells. We thus propose to consider those mitochondrial and metabolic changes as hallmarks of differentiation processes. We review how mitochondrial biogenesis, dynamics, and function are directly involved in embryonic and SSC differentiation and how metabolic and sensing pathways connect mitochondria and metabolism with cell fate and pluripotency. Understanding the basis of the crosstalk between mitochondria and cell fate is of critical importance, given the promising application of stem cells in regenerative medicine. In addition to the development of novel strategies to improve the in vitro lineage-directed differentiation of stem cells, understanding the molecular basis of this interplay could lead to the identification of novel targets to improve the treatment of degenerative diseases.

  2. Fate in the religion of the Lepchas

    Directory of Open Access Journals (Sweden)

    Halfdan Siiger

    1967-02-01

    Full Text Available The Lepchas are mountainous agriculturalists who live in the State of Sikkim in the Himalayas and in some adjacent Indian districts. To the Lepchas the supernatural world is divided into two groups, the rum, or the mainly benevolent supernatural beings, and the mung, or the malignant supernatural beings. Any evil occurrence is in the first instance ascribed to the malignant activities of the mung, but it may, under certain conditions, also be due to temporary on the part of some or other rum. If it is obvious that the evil occurrence is caused by a human being, this person is considered to be governed by some mung, or he may, which is much worse, be a mung in human disguise. At all events, any evil occurrence is experienced as the result of the evil will-power of some or other malignant supernatural being. Consequently, we cannot apply our technical term "Fate" to such occurrences, and Fate as an abstract concept cannot be used, when we speak of the Lepchas.

  3. Multi-Analytic Based Determination of Substrate Fate From in situ Stable Isotope Labeled Exposures of Natural Microbial Mats

    Science.gov (United States)

    Lipton, M. S.; Cory, A.; Riha, K. M.; Huang, E. L.; Boaro, A. A.; Metz, T. O.; Gritsenko, M. A.; Mobberley, J. M.; Nelson, W.; Kim, Y. M.; Moran, J.

    2015-12-01

    Microbial communities play impactful roles in almost every aspect of our society including the environment, climate, agriculture and human health, expanding the functional capacity of life on earth. The recent emergence of a suite of omics driven technologies offers powerful tools for investigating functionality of this community. However, these tools provide only a static snapshot of the community in space and time. The temporal nature of stable isotope probing (SIP) experiments expands the depth at which microbial communities can be investigated and understood. While selectively targeting only metabolically active organisms in a community, the labeled substrate can be tracked spatially, temporally and phylo-genetically and linked to active functions, organism interactions and exchanges. Single SIP technologies are limited in their ability to describe the biological system as a whole. However, integration of multiple SIP based analytics offers a more comprehensive description of substrate fate. The phototroph based microbial mat community resident in Hot Lake, a hypersaline lake located in Washington State, offers a tractable system for testing the multi analytic approach. We exposed the mat to three different 13C-labeled substrates (HCO3-, glucose and acetate) in situ at midday, and subsequently analyzed the mat 24 hours after incubation. The approach revealed different metabolic fates and organism specific uptake. When compared to acetate, glucose and HCO3- showed a greater incorporation into extracellular material, while acetate had a greater conversion to intracellular fatty acids, suggesting that HCO3- and glucose could be more readily shared as a community currency than acetate. All substrates were converted to amino acids and proteins, but while glucose and HCO3- demonstrated considerable incorporation into heterotrophic proteins, the conversion of acetate to these proteins was minimal, potentially implying that acetate derived intermediates are not a

  4. Transcriptional control of stem cell fate by E2Fs and Pocket Proteins

    Directory of Open Access Journals (Sweden)

    Lisa Marie Julian

    2015-04-01

    Full Text Available E2F transcription factors and their regulatory partners, the pocket proteins (PPs, have emerged as essential regulators of stem cell fate control in a number of lineages. In mammals, this role extends from both pluripotent stem cells to those encompassing all embryonic germ layers, as well as extra-embryonic lineages. E2F/PP-mediated regulation of stem cell decisions is highly evolutionarily conserved, and is likely a pivotal biological mechanism underlying stem cell homeostasis. This has immense implications for organismal development, tissue maintenance and regeneration. In this article, we discuss the roles of E2F factors and PPs in stem cell populations, focusing on mammalian systems. We discuss emerging findings that position the E2F and PP families as widespread and dynamic epigenetic regulators of cell fate decisions. Additionally, we focus on the ever expanding landscape of E2F/PP target genes, and explore the possibility that E2Fs are not simply regulators of general ‘multi-purpose’ cell fate genes but can execute tissue- and cell type-specific gene regulatory programs.

  5. Time-variant clustering model for understanding cell fate decisions.

    Science.gov (United States)

    Huang, Wei; Cao, Xiaoyi; Biase, Fernando H; Yu, Pengfei; Zhong, Sheng

    2014-11-01

    Both spatial characteristics and temporal features are often the subjects of concern in physical, social, and biological studies. This work tackles the clustering problems for time course data in which the cluster number and clustering structure change with respect to time, dubbed time-variant clustering. We developed a hierarchical model that simultaneously clusters the objects at every time point and describes the relationships of the clusters between time points. The hidden layer of this model is a generalized form of branching processes. A reversible-jump Markov Chain Monte Carlo method was implemented for model inference, and a feature selection procedure was developed. We applied this method to explore an open question in preimplantation embryonic development. Our analyses using single-cell gene expression data suggested that the earliest cell fate decision could start at the 4-cell stage in mice, earlier than the commonly thought 8- to 16-cell stage. These results together with independent experimental data from single-cell RNA-seq provided support against a prevailing hypothesis in mammalian development. PMID:25339442

  6. Cell fate determination in the Caenorhabditis elegans epidermal lineages

    NARCIS (Netherlands)

    Soete, G.A.J.

    2007-01-01

    The starting point for this work was to use the hypodermal seam of C. elegans as a model system to study cell fate determination. Even though the seam is a relatively simple developmental system, the mechanisms that control cell fate determination in the seam lineages are connected in a highly compl

  7. Fate and Bioavailability of Engineered Nanoparticles in Soils: A Review

    NARCIS (Netherlands)

    Cornelis, G.; Hund-Rinke, K.; Kuhlbusch, T.; Brink, van den N.W.; Nickel, C.

    2014-01-01

    Interactions within natural soils have often been neglected when assessing fate and bioavailability of engineered nanomaterials (ENM) in soils. This review combines patchwise ENM research using natural soils with the much wider literature on ENM performed in standard tests or on the fate of colloids

  8. Fate of geothermal mercury from Yellowstone National Park in the Madison and Missouri Rivers, USA.

    Science.gov (United States)

    Nimick, David A; Caldwell, Rodney R; Skaar, Donald R; Selch, Trevor M

    2013-01-15

    Mercury is a worldwide contaminant derived from natural and anthropogenic sources. River systems play a key role in the transport and fate of Hg because they drain widespread areas affected by aerial Hg deposition, transport Hg away from point sources, and are sites of Hg biogeochemical cycling and bioaccumulation. The Madison and Missouri Rivers provide a natural laboratory for studying the fate and transport of Hg contributed by geothermal discharge in Yellowstone National Park and from the atmosphere for a large drainage basin in Montana and Wyoming, United States of America (USA). Assessing Hg in these rivers also is important because they support fishery-based recreation and irrigated agriculture. During 2002 to 2006, Hg concentrations were measured in water, sediment, and fish from the main stem, 7 tributaries, and 6 lakes. Using these data, the geothermal Hg load to the Madison River and overall fate of Hg along 378 km of the Missouri River system were assessed. Geothermal Hg was the primary source of elevated total Hg concentrations in unfiltered water (6.2-31.2 ng/L), sediment (148-1100 ng/g), and brown and rainbow trout (0.12-1.23 μg total Hg/g wet weight skinless filet) upstream from Hebgen Lake (the uppermost impoundment). Approximately 7.0 kg/y of geothermal Hg was discharged from the park via the Madison River, and an estimated 87% of that load was lost to sedimentation in and volatilization from Hebgen Lake. Consequently, Hg concentrations in water, sediment, and fish from main-stem sites downstream from Hebgen Lake were not elevated and were comparable to concentrations reported for other areas affected solely by atmospheric Hg deposition. Some Hg was sequestered in sediment in the downstream lakes. Bioaccumulation of Hg in fish along the river system was strongly correlated (r(2)=0.76-0.86) with unfiltered total and methyl Hg concentrations in water and total Hg in sediment.

  9. Finding novel pharmaceuticals in the systems biology era using multiple effective drug targets, phenotypic screening and knowledge of transporters: where drug discovery went wrong and how to fix it.

    Science.gov (United States)

    Kell, Douglas B

    2013-12-01

    Despite the sequencing of the human genome, the rate of innovative and successful drug discovery in the pharmaceutical industry has continued to decrease. Leaving aside regulatory matters, the fundamental and interlinked intellectual issues proposed to be largely responsible for this are: (a) the move from 'function-first' to 'target-first' methods of screening and drug discovery; (b) the belief that successful drugs should and do interact solely with single, individual targets, despite natural evolution's selection for biochemical networks that are robust to individual parameter changes; (c) an over-reliance on the rule-of-5 to constrain biophysical and chemical properties of drug libraries; (d) the general abandoning of natural products that do not obey the rule-of-5; (e) an incorrect belief that drugs diffuse passively into (and presumably out of) cells across the bilayers portions of membranes, according to their lipophilicity; (f) a widespread failure to recognize the overwhelmingly important role of proteinaceous transporters, as well as their expression profiles, in determining drug distribution in and between different tissues and individual patients; and (g) the general failure to use engineering principles to model biology in parallel with performing 'wet' experiments, such that 'what if?' experiments can be performed in silico to assess the likely success of any strategy. These facts/ideas are illustrated with a reasonably extensive literature review. Success in turning round drug discovery consequently requires: (a) decent systems biology models of human biochemical networks; (b) the use of these (iteratively with experiments) to model how drugs need to interact with multiple targets to have substantive effects on the phenotype; (c) the adoption of polypharmacology and/or cocktails of drugs as a desirable goal in itself; (d) the incorporation of drug transporters into systems biology models, en route to full and multiscale systems biology models that

  10. Putting things in place for fertilization: discovering roles for importin proteins in cell fate and spermatogenesis

    Directory of Open Access Journals (Sweden)

    Kate L. Loveland

    2015-01-01

    Full Text Available Importin proteins were originally characterized for their central role in protein transport through the nuclear pores, the only intracellular entry to the nucleus. This vital function must be tightly regulated to control access by transcription factors and other nuclear proteins to genomic DNA, to achieve appropriate modulation of cellular behaviors affecting cell fate. Importin-mediated nucleocytoplasmic transport relies on their specific recognition of cargoes, with each importin binding to distinct and overlapping protein subsets. Knowledge of importin function has expanded substantially in regard to three key developmental systems: embryonic stem cells, muscle cells and the germ line. In the decade since the potential for regulated nucleocytoplasmic transport to contribute to spermatogenesis was proposed, we and others have shown that the importins that ferry transcription factors into the nucleus perform additional roles, which control cell fate. This review presents key findings from studies of mammalian spermatogenesis that reveal potential new pathways by which male fertility and infertility arise. These studies of germline genesis illuminate new ways in which importin proteins govern cellular differentiation, including via directing proteins to distinct intracellular compartments and by determining cellular stress responses.

  11. Modeling and measuring the fate of Methabenzthiazuron at the lysimeter scale

    Science.gov (United States)

    Herbst, M.; Pütz, T.; Ciocanaru, M.; Vereecken, H.

    2003-04-01

    For the modeling of pesticide fate at regional scales we try to scale up local scale process knowledge. The validation at the local scale can be seen as a prerequisite for large scale modeling of pesticide transport. The aim of this study is to evaluate the performance of the coupled multi-scale model system TRACE/3dLEWASTE to predict water flow, crop development and pesticide transport in a lysimeter for a two year simulation period. TRACE/3dLEWASTE is tested at the local scale and will be used at regional scale. The experimental setup consists of a 1.1 m undisturbed soil column (eutric Luvisol) with 1 m2 surface. Winter wheat, winter barley and oat was grown according to common farming practice. The measurement of evapotranspiration, drainage flow, soil moisture content and pesticide concentrations allows the validation of model output. TRACE is a finite element model based on a numerical solution of the Richards' equation. For solute transport we use 3dLEWASTE which applies a hybrid Eulerian-Lagrangian approach. Linear sorption and a first order decay was assumed. Sorption and degradation parameters are taken from laboratory experiments. The quantification of model performance reveals a good agreement between model prediction and measurements for the water flow, whereas a less accurate prediction of pesticide fate was detected. This can be seen as a result of uncertain sorption and degradation parameters or even as a result of an inadequate process description.

  12. Asymmetric cell division during T cell development controls downstream fate

    Science.gov (United States)

    Pham, Kim; Shimoni, Raz; Charnley, Mirren; Ludford-Menting, Mandy J.; Hawkins, Edwin D.; Ramsbottom, Kelly; Oliaro, Jane; Izon, David; Ting, Stephen B.; Reynolds, Joseph; Lythe, Grant; Molina-Paris, Carmen; Melichar, Heather; Robey, Ellen; Humbert, Patrick O.; Gu, Min

    2015-01-01

    During mammalian T cell development, the requirement for expansion of many individual T cell clones, rather than merely expansion of the entire T cell population, suggests a possible role for asymmetric cell division (ACD). We show that ACD of developing T cells controls cell fate through differential inheritance of cell fate determinants Numb and α-Adaptin. ACD occurs specifically during the β-selection stage of T cell development, and subsequent divisions are predominantly symmetric. ACD is controlled by interaction with stromal cells and chemokine receptor signaling and uses a conserved network of polarity regulators. The disruption of polarity by deletion of the polarity regulator, Scribble, or the altered inheritance of fate determinants impacts subsequent fate decisions to influence the numbers of DN4 cells arising after the β-selection checkpoint. These findings indicate that ACD enables the thymic microenvironment to orchestrate fate decisions related to differentiation and self-renewal. PMID:26370500

  13. The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

    DEFF Research Database (Denmark)

    Douglas, Thomas A.; Loseto, Lisa L.; MacDonald, Robie W.;

    2012-01-01

    into the Arctic by oceanic, atmospheric and terrestrial pathways. Our focus is on the movement, transformation and bioaccumulation of Hg in aquatic (marine and fresh water) and terrestrial ecosystems. The processes most relevant to biological Hg uptake and the potential risk associated with Hg exposure...... the fate of Hg in most ecosystems, and the role of trophic processes in controlling Hg in higher order animals are also included. Case studies on Eastern Beaufort Sea beluga (Delphinapterus leucas) and landlocked Arctic char (Salvelinus alpinus) are presented as examples of the relationship between...

  14. Sources, Fate and Distribution of Organic Matter on the Western Adriatic Continental Shelf, Italy

    Energy Technology Data Exchange (ETDEWEB)

    Tesi, Tommaso, E-mail: tommaso.tesi@bo.ismar.cnr.it; Miserocchi, Stefano; Langone, Leonardo [ISMAR-CNR, Sede di Bologna - Geologia Marina (Italy); Boni, Laurita; Guerrini, Franca [Universita di Bologna, Laboratorio di Biologia e Fisiologia Algale, Sc. Ambientali (Italy)

    2006-12-15

    In the framework of the EUROSTRATAFORM projects, a multidisciplinary research was focused on processes that involve transport and deposition of riverine material in the Adriatic Sea. The aim of our contribution was to increase a more complete understanding of organic matter deposition on the Adriatic shelf, also taking into account the role of Apennine rivers beyond the Po influence. In order to characterize origin, fate and variability of sedimentary organic carbon we utilized elemental and stable carbon isotope data in surficial sediments along shallow cross-shelf transects on the western Adriatic shelf.

  15. Aquatic pathways model to predict the fate of phenolic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Aaberg, R.L.; Peloquin, R.A.; Strenge, D.L.; Mellinger, P.J.

    1983-04-01

    Organic materials released from energy-related activities could affect human health and the environment. To better assess possible impacts, we developed a model to predict the fate of spills or discharges of pollutants into flowing or static bodies of fresh water. A computer code, Aquatic Pathways Model (APM), was written to implement the model. The computer programs use compartmental analysis to simulate aquatic ecosystems. The APM estimates the concentrations of chemicals in fish tissue, water and sediment, and is therefore useful for assessing exposure to humans through aquatic pathways. The APM will consider any aquatic pathway for which the user has transport data. Additionally, APM will estimate transport rates from physical and chemical properties of chemicals between several key compartments. The major pathways considered are biodegradation, fish and sediment uptake, photolysis, and evaporation. The model has been implemented with parameters for distribution of phenols, an important class of compounds found in the water-soluble fractions of coal liquids. Current modeling efforts show that, in comparison with many pesticides and polyaromatic hydrocarbons (PAH), the lighter phenolics (the cresols) are not persistent in the environment. The properties of heavier molecular weight phenolics (indanols, naphthols) are not well enough understood at this time to make similar judgements. For the twelve phenolics studied, biodegradation appears to be the major pathway for elimination from aquatic environments. A pond system simulation (using APM) of a spill of solvent refined coal (SRC-II) materials indicates that phenol, cresols, and other single cyclic phenolics are degraded to 16 to 25 percent of their original concentrations within 30 hours. Adsorption of these compounds into sediments and accumulation by fish was minor.

  16. Indoor Air Nuclear, Biological, and Chemical Health Modeling and Assessment System

    Energy Technology Data Exchange (ETDEWEB)

    Stenner, Robert D.; Hadley, Donald L.; Armstrong, Peter R.; Buck, John W.; Hoopes, Bonnie L.; Janus, Michael C.

    2001-03-01

    Indoor air quality effects on human health are of increasing concern to public health agencies and building owners. The prevention and treatment of 'sick building' syndrome and the spread of air-borne diseases in hospitals, for example, are well known priorities. However, increasing attention is being directed to the vulnerability of our public buildings/places, public security and national defense facilities to terrorist attack or the accidental release of air-borne biological pathogens, harmful chemicals, or radioactive contaminants. The Indoor Air Nuclear, Biological, and Chemical Health Modeling and Assessment System (IA-NBC-HMAS) was developed to serve as a health impact analysis tool for use in addressing these concerns. The overall goal was to develop a user-friendly fully functional prototype Health Modeling and Assessment system, which will operate under the PNNL FRAMES system for ease of use and to maximize its integration with other modeling and assessment capabilities accessible within the FRAMES system (e.g., ambient air fate and transport models, water borne fate and transport models, Physiologically Based Pharmacokinetic models, etc.). The prototype IA-NBC-HMAS is designed to serve as a functional Health Modeling and Assessment system that can be easily tailored to meet specific building analysis needs of a customer. The prototype system was developed and tested using an actual building (i.e., the Churchville Building located at the Aberdeen Proving Ground) and release scenario (i.e., the release and measurement of tracer materials within the building) to ensure realism and practicality in the design and development of the prototype system. A user-friendly "demo" accompanies this report to allow the reader the opportunity for a "hands on" review of the prototype system's capability.

  17. SCARECROW, SCR-LIKE 23 and SHORT-ROOT control bundle sheath cell fate and function in Arabidopsis thaliana.

    Science.gov (United States)

    Cui, Hongchang; Kong, Danyu; Liu, Xiuwen; Hao, Yueling

    2014-04-01

    Bundle sheath (BS) cells form a single cell layer surrounding the vascular tissue in leaves. In C3 plants, photosynthesis occurs in both the BS and mesophyll cells, but the BS cells are the major sites of photosynthesis in C4 plants, whereas the mesophyll cells are only involved in CO2 fixation. Because C4 plants are more efficient photosynthetically, introduction of the C4 mechanism into C3 plants is considered a key strategy to improve crop yield. One prerequisite for such C3-to-C4 engineering is the ability to manipulate the number and physiology of the BS cells, but the molecular basis of BS cell-fate specification remains unclear. Here we report that mutations in three GRAS family transcription factors, SHORT-ROOT (SHR), SCARECROW (SCR) and SCARECROW-LIKE 23 (SCL23), affect BS cell fate in Arabidopsis thaliana. SCR and SCL23 are expressed specifically in the BS cells and act redundantly in BS cell-fate specification, but their expression pattern and function diverge at later stages of leaf development. Using ChIP-chip experiments and sugar assays, we show that SCR is primarily involved in sugar transport whereas SCL23 functions in mineral transport. SHR is also essential for BS cell-fate specification, but it is expressed in the central vascular tissue. However, the SHR protein moves into the BS cells, where it directly regulates SCR and SCL23 expression. SHR, SCR and SCL23 homologs are present in many plant species, suggesting that this developmental pathway for BS cell-fate specification is likely to be evolutionarily conserved.

  18. Conceptual Site Model for Newark Bay—Hydrodynamics and Sediment Transport

    Directory of Open Access Journals (Sweden)

    Parmeshwar L. Shrestha

    2014-02-01

    Full Text Available A conceptual site model (CSM has been developed for the Newark Bay Study Area (NBSA as part of the Remedial Investigation/Feasibility Study (RI/FS for this New Jersey site. The CSM is an evolving document that describes the influence of physical, chemical and biological processes on contaminant fate and transport. The CSM is initiated at the start of a project, updated during site activities, and used to inform sampling and remediation planning. This paper describes the hydrodynamic and sediment transport components of the CSM for the NBSA. Hydrodynamic processes are influenced by freshwater inflows, astronomical forcing through two tidal straits, meteorological conditions, and anthropogenic activities such as navigational dredging. Sediment dynamics are driven by hydrodynamics, waves, sediment loading from freshwater sources and the tidal straits, sediment size gradation, sediment bed properties, and particle-to-particle interactions. Cohesive sediment transport is governed by advection, dispersion, aggregation, settling, consolidation, and erosion. Noncohesive sediment transport is governed by advection, dispersion, settling, armoring, and transport in suspension and along the bed. The CSM will inform the development and application of a numerical model that accounts for all key variables to adequately describe the NBSA’s historical, current, and future physical conditions.

  19. Phenomenological and Spectroscopic Analysis on the Effects of Sediment Ageing and Organic Carbon on the Fate of a PCB Congener Spiked to Sediment

    Science.gov (United States)

    This study assesses the full cycle transport and fate of a polychlorinated biphenyl (PCB) congener spiked to sediment to empirically and spectroscopically investigate the effects of sediment ageing and organic carbon on the adsorption, desorption, and reaction of the PCB. Caesar ...

  20. Biological and Clinical Study of 6-Deoxy-6-Iodo-D-Glucose: a iodinated tracer of glucose transport and of insulin-resistance in human

    International Nuclear Information System (INIS)

    Insulin resistance (IR), characterized by a depressed cellular sensitivity to insulin in insulin-sensitive organs, is a central feature to obesity, the metabolic syndrome, and diabetes mellitus and leads to increase cardiovascular diseases, particularly heart failure. All these events are today serious public health problems. But actually, there is no simple tool to measure insulin resistance. The gold standard technique remains the hyperinsulinemic euglycemic clamp. However, the complexity and length of this technique render it unsuitable for routine clinical use. Many methods or index have been proposed to assess insulin resistance in human, but none have shown enough relevance to be used in clinical use. The U1039 INSERM unit previously has validated a new tracer of glucose transport, radiolabelled with 123 iodine and has developed a fast and simple imaging protocol with a small animal gamma camera, which allows the obtaining of an IR index for each organ, showing more discriminating for the heart. The project of my thesis was the human transfer of this measurement technique, perfectly validated in animal. The first part of this thesis evaluated to tolerance, in vivo kinetics, distribution and dosimetry of novel tracer of glucose transport, the [123I]-6DIG. The safeties of new tracer and measurement technique were adequate. There were no adverse effects with excellent tolerance of the whole protocol. 6DIG eliminating was fast, primarily in the urine and complete within 72 h. The effective whole-body absorbed dose for a complete scan with injection of 92.5 * 2 MBq was between 3 to 4 mSv. The second part of this thesis evaluated in human feasibility and reproducibility of the measurement technique validated in animal. The third part showed techniques used to allow human transfer of this method. The study protocol was applied on 12 subjects (healthy volunteers (n=6) and type 2 diabetic patients (n=6)). With a method adapted to measure in humans, we determined an IR

  1. CBC bound proteins and RNA fate

    DEFF Research Database (Denmark)

    Giacometti, Simone

    2016-01-01

    ) complex (CBCN), were recently shown to target capped RNA either toward export or degradation, but the mechanisms by which they can discriminate between different RNA families and route them toward different metabolic pathways still remain unclear. A major question to be answered is how and when...... the different CBC subcomplexes are recruited to the RNP. Here, we used an individual nucleotide-resolution UV cross-linking and immunoprecipitation (iCLIP) approach to identify the transcriptome-wide targets for 5 different components of the CBCAP and CBCN complexes, and compared results to the previously......), while MTR4 is additionally present on mature RNAs. Although more experimental work is needed to fully support our model, we propose that CBCAP and CBCN bind overlapping sets of RNAs, indicating a competition between the proteins ZC3H18 and PHAX, and the lack of a strict RNA sorting mechanism. RNA fate...

  2. Fate of pesticides during beer brewing.

    Science.gov (United States)

    Inoue, Tomonori; Nagatomi, Yasushi; Suga, Keiko; Uyama, Atsuo; Mochizuki, Naoki

    2011-04-27

    The fates of more than 300 pesticide residues were investigated in the course of beer brewing. Ground malt artificially contaminated with pesticides was brewed via steps such as mashing, boiling, and fermentation. Analytical samples were taken from wort, spent grain, and beer produced at certain key points in the brewing process. The samples were extracted and purified with the QuEChERS (Quick Easy Cheap Effective Rugged and Safe) method and were then analyzed by LC-MS/MS using a multiresidue method. In the results, a majority of pesticides showed a reduction in the unhopped wort and were adsorbed onto the spent grain after mashing. In addition, some pesticides diminished during the boiling and fermentation. This suggests that the reduction was caused mainly by adsorption, pyrolysis, and hydrolysis. After the entire process of brewing, the risks of contaminating beer with pesticides were reduced remarkably, and only a few pesticides remained without being removed or resolved.

  3. A D Sakharov: personality and fate

    International Nuclear Information System (INIS)

    A D Sakharov was an amazingly gifted person for whom, with his combined talents as a physicist and inventor, ''physical laws and the relation among phenomena were directly visualized and tangible in all their inherent simplicity'' (I E Tamm). The author of the key ideas involved in the hydrogen weapons and fusion reactor programs, and well aware of his scientific and public status, Sakharov was, nevertheless, a modest and highly decent man, always trustful of people in discussing their or his problems. Although his greatest satisfaction lay in successfully solving fundamental problems in physics and cosmology, fate and duty made him turn to matters of universal human significance, particularly human rights, to the gruelling struggle to which he devoted many years of his life. (conferences and symposia)

  4. A D Sakharov: personality and fate

    Science.gov (United States)

    Ritus, Vladimir I.

    2012-02-01

    A D Sakharov was an amazingly gifted person for whom, with his combined talents as a physicist and inventor, "physical laws and the relation among phenomena were directly visualized and tangible in all their inherent simplicity" (I E Tamm). The author of the key ideas involved in the hydrogen weapons and fusion reactor programs, and well aware of his scientific and public status, Sakharov was, nevertheless, a modest and highly decent man, always trustful of people in discussing their or his problems. Although his greatest satisfaction lay in successfully solving fundamental problems in physics and cosmology, fate and duty made him turn to matters of universal human significance, particularly human rights, to the gruelling struggle to which he devoted many years of his life.

  5. Binary cell fate decisions and fate transformation in the Drosophila larval eye.

    Directory of Open Access Journals (Sweden)

    Abhishek Kumar Mishra

    Full Text Available The functionality of sensory neurons is defined by the expression of specific sensory receptor genes. During the development of the Drosophila larval eye, photoreceptor neurons (PRs make a binary choice to express either the blue-sensitive Rhodopsin 5 (Rh5 or the green-sensitive Rhodopsin 6 (Rh6. Later during metamorphosis, ecdysone signaling induces a cell fate and sensory receptor switch: Rh5-PRs are re-programmed to express Rh6 and become the eyelet, a small group of extraretinal PRs involved in circadian entrainment. However, the genetic and molecular mechanisms of how the binary cell fate decisions are made and switched remain poorly understood. We show that interplay of two transcription factors Senseless (Sens and Hazy control cell fate decisions, terminal differentiation of the larval eye and its transformation into eyelet. During initial differentiation, a pulse of Sens expression in primary precursors regulates their differentiation into Rh5-PRs and repression of an alternative Rh6-cell fate. Later, during the transformation of the larval eye into the adult eyelet, Sens serves as an anti-apoptotic factor in Rh5-PRs, which helps in promoting survival of Rh5-PRs during metamorphosis and is subsequently required for Rh6 expression. Comparably, during PR differentiation Hazy functions in initiation and maintenance of rhodopsin expression. Hazy represses Sens specifically in the Rh6-PRs, allowing them to die during metamorphosis. Our findings show that the same transcription factors regulate diverse aspects of larval and adult PR development at different stages and in a context-dependent manner.

  6. Using ANN to predict E. coli accumulation in coves based on interaction amongst various physical, chemical and biological factors

    Science.gov (United States)

    Dwivedi, D.; Mohanty, B. P.; Lesikar, B. J.

    2008-12-01

    The accumulation of Escherichia Coli (E. coli) in canals, coves and streams is the result of a number of interacting processes operating at multiple spatial and temporal scales. Fate and transport of E. coli in surface water systems is governed by different physical, chemical, and biological processes. Various models developed to quantify each of these processes occurring at different scales are not so far pooled into a single predictive model. At present, very little is known about the fate and transport of E. coli in the environment. We hypothesize that E. coli population heterogeneity in canals and coves is affected by physical factors (average stream width and/ depth, secchi depth, flow and flow severity, day since precipitation, aquatic vegetation, solar radiation, dissolved and total suspended solids etc.); chemical factors (basic water quality, nutrients, organic compounds, pH, and toxicity etc.); and biological factors (type of bacterial strain, predation, and antagonism etc.). The specific objectives of this study are to: (1) examine the interactions between E. coli and various coupled physical, chemical and biological factors; (2) examine the interactions between E. coli and toxic organic pollutants and other pathogens (viruses); and (3) evaluate qualitatively the removal efficiency of E. coli. We suggest that artificial neural networks (ANN) may be used to provide a possible solution to this problem. To demonstrate the application of the approach, we develop an ANN representing E. coli accumulation in two polluted sites at Lake Granbury in the upper part of the Brazos River in North Central Texas. The graphical structure of ANN explicitly represents cause- and-effect relationship between system variables. Each of these relationships can then be quantified independently using an approach suitable for the type and scale of information available. Preliminary results revealed that E. coli concentrations in canals show seasonal variations regardless of change

  7. Second report on the Oak Ridge National Laboratory Biological Monitoring and Abatement Program for White Oak Creek Watershed and the Clinch River

    Energy Technology Data Exchange (ETDEWEB)

    Loar, J.M. [ed.; Adams, S.M.; Bailey, R.D.; Blaylock, B.G.; Boston, H.L.; Cox, D.K.; Huston, M.A.; Kimmel, B.L.; Loar, J.M.; Olsen, C.R.; Ryon, M.G.; Shugart, L.R.; Smith, J.G.; Southworth, G.R.; Stewart, A.J.; Walton, B.T.; Talmage, S.S.; Murphy, J.B.; Valentine, C.K. [Oak Ridge National Lab., TN (United States); Appellanis, S.M.; Jimenez, B.D. [Puerto Rico Univ., San Juan (Puerto Rico); Huq, M.V. [Connecticut Dept. of Environmental Protection, Hamden, CT (United States); Meyers-Schone, L.J. [Frankfurter, Gross-Gerau (Germany); Mohrbacher, D.A. [Automated Sciences Group, Inc., Oak Ridge, TN (United States); Olsen, C.R. [USDOE Office of Energy Research, Washington, DC (United States). Environmental Sciences Div.; Stout, J.G. [Cincinnati Univ., OH (United States)

    1992-12-01

    As a condition of the National Pollutant Discharge Elimination System (NPDES) permit issued to Oak Ridge National Laboratory (ORNL) on April 1, 1986, a Biological Monitoring and Abatement Program (BMAP) was developed for White Oak Creek (WOC); selected tributaries of WOC, including Fifth Creek, First Creek, Melton Branch, and Northwest Tributary; and the Clinch River. BMAP consists of seven major tasks that address both radiological and nonradiological contaminants in the aquatic and terrestrial environs on-site and the aquatic environs off-site. These tasks are (1) toxicity monitoring; (2) bioaccumulation monitoring of nonradiological contaminants in aquatic biota; (3) biological indicator studies; (4) instream ecological monitoring; (5) assessment of contaminants in the terrestrial environment; (6) radioecology of WOC and White Oak Lake (WOL); and (7) contaminant transport, distribution, and fate in the WOC embayment-Clinch River-Watts Bar Reservoir system. This document, the second of a series of annual reports, described the results of BMAP studies conducted in 1987.

  8. Second report on the Oak Ridge National Laboratory Biological Monitoring and Abatement Program for White Oak Creek Watershed and the Clinch River

    International Nuclear Information System (INIS)

    As a condition of the National Pollutant Discharge Elimination System (NPDES) permit issued to Oak Ridge National Laboratory (ORNL) on April 1, 1986, a Biological Monitoring and Abatement Program (BMAP) was developed for White Oak Creek (WOC); selected tributaries of WOC, including Fifth Creek, First Creek, Melton Branch, and Northwest Tributary; and the Clinch River. BMAP consists of seven major tasks that address both radiological and nonradiological contaminants in the aquatic and terrestrial environs on-site and the aquatic environs off-site. These tasks are (1) toxicity monitoring; (2) bioaccumulation monitoring of nonradiological contaminants in aquatic biota; (3) biological indicator studies; (4) instream ecological monitoring; (5) assessment of contaminants in the terrestrial environment; (6) radioecology of WOC and White Oak Lake (WOL); and (7) contaminant transport, distribution, and fate in the WOC embayment-Clinch River-Watts Bar Reservoir system. This document, the second of a series of annual reports, described the results of BMAP studies conducted in 1987

  9. Chlorinated paraffins in the environment: A review on their production, fate, levels and trends between 2010 and 2015.

    Science.gov (United States)

    van Mourik, Louise M; Gaus, Caroline; Leonards, Pim E G; de Boer, Jacob

    2016-07-01

    This review provides an update on information regarding the production volumes, regulations, as well as the environmental levels, trends, fate and human exposure to chlorinated paraffin mixtures (CPs). CPs encompas thousands congeners with varying properties and environmental fate. Based on their carbon chain lengths, CPs are divided into short- (SCCPs; C10-13), medium- (MCCPs; C14-17) and long- (LCCPs; C ≥ 18) chained groups. They are high production volume and persistent chemicals, and their cumulative global production already surpasses that of other persistent anthropogenic chemicals (e.g. PCBs). However, international regulations are still curbed by insufficient information on their levels and fate, including bioaccumulation and toxicity potential. An increasing number of studies since 2010 demonstrate that CPs are detected in almost every compartment in the environment, including remote areas. Consensus on the long range transport and high bioaccumulation potential (BCF > 5000 & TMF > 1) has recently been reached for SCCPs, fulfilling criteria under the Stockholm Convention for designation as a persistent organic pollutant; information on their levels is, however, still sparse for many countries. M/LCCPs have received comparatively little attention in the past, but as replacement chemicals for SCCPs, MCCPs are now considered in an increasing number of studies. The limited data to date suggests MCCPs are widely used. Although data on their bioaccumulation and toxicity are still inconclusive, MCCPs and LCCPs with Cenvironment, a better understanding on the levels and fate of all CPs is needed. PMID:27135701

  10. Biological nitrate transport in sediments on the Peruvian margin mitigates benthic sulfide emissions and drives pelagic N loss during stagnation events

    Science.gov (United States)

    Dale, A. W.; Sommer, S.; Lomnitz, U.; Bourbonnais, A.; Wallmann, K.

    2016-06-01

    Benthic N cycling in the Peruvian oxygen minimum zone (OMZ) was investigated at ten stations along 12 °S from the middle shelf (74 m) to the upper slope (1024 m) using in situ flux measurements, sediment biogeochemistry and modeling. Middle shelf sediments were covered by mats of the filamentous bacteria Thioploca spp. and contained a large 'hidden' pool of nitrate that was not detectable in the porewater. This was attributed to a biological nitrate reservoir stored within the bacteria to oxidize sulfide during 'dissimilatory nitrate reduction to ammonium' (DNRA). The extremely high rates of DNRA on the shelf (15.6 mmol m-2 d-1 of N), determined using an empirical steady-state model, could easily supply all the ammonium requirements for anammox in the water column. The model further showed that denitrification by foraminifera may account for 90% of N2 production at the lower edge of the OMZ. At the time of sampling, dissolved oxygen was below detection limit down to 400 m and the water body overlying the shelf had stagnated, resulting in complete depletion of nitrate and nitrite. A decrease in the biological nitrate pool was observed on the shelf during fieldwork concomitant with a rise in porewater sulfide levels in surface sediments to 2 mM. Using a non-steady state model to simulate this natural anoxia experiment, these observations were shown to be consistent with Thioploca surviving on a dwindling intracellular nitrate reservoir to survive the stagnation period. The model shows that sediments hosting Thioploca are able to maintain high ammonium fluxes for many weeks following stagnation, potentially sustaining pelagic N loss by anammox. In contrast, sulfide emissions remain low, reducing the economic risk to the Peruvian fishery by toxic sulfide plume development.

  11. Fast Neutron Transport in the Biological Shielding Model and Other Regions of the VVER-1000 Mock-Up on the LR-0 Research Reactor

    Science.gov (United States)

    Košťál, Michal; Milčák, Ján; Cvachovec, František; Jánský, Bohumil; Rypar, Vojtěch; Juříček, Vlastimil; Novák, Evžen; Egorov, Alexander; Zaritskiy, Sergey

    2016-02-01

    A set of benchmark experiments was carried out in the full scale VVER-1000 mock-up on the reactor LR-0 in order to validate neutron transport calculation methodologies and to perform the optimization of the shape and locations of neutron flux operation monitors channels inside the shielding of the new VVER-1000 type reactors. Compared with previous experiments on the VVER-1000 mock-up on the reactor LR-0, the fast neutron spectra were measured in the extended neutron energy interval (0.1-10 MeV) and new calculations were carried out with the MCNPX code using various nuclear data libraries (ENDF/B VII.0, JEFF 3.1, JENDL 3.3, JENDL 4, ROSFOND 2009, and CENDL 3.1). Measurements and calculations were carried out at different points in the mock-up. The calculation and experimental data are compared.

  12. Fast Neutron Transport in the Biological Shielding Model and Other Regions of the VVER-1000 Mock-Up on the LR-0 Research Reactor

    Directory of Open Access Journals (Sweden)

    Košťál Michal

    2016-01-01

    Full Text Available A set of benchmark experiments was carried out in the full scale VVER-1000 mock-up on the reactor LR-0 in order to validate neutron transport calculation methodologies and to perform the optimization of the shape and locations of neutron flux operation monitors channels inside the shielding of the new VVER-1000 type reactors. Compared with previous experiments on the VVER-1000 mock-up on the reactor LR-0, the fast neutron spectra were measured in the extended neutron energy interval (0.1–10 MeV and new calculations were carried out with the MCNPX code using various nuclear data libraries (ENDF/B VII.0, JEFF 3.1, JENDL 3.3, JENDL 4, ROSFOND 2009, and CENDL 3.1. Measurements and calculations were carried out at different points in the mock-up. The calculation and experimental data are compared.

  13. Chemical approaches to studying stem cell biology

    Institute of Scientific and Technical Information of China (English)

    Wenlin Li; Kai Jiang; Wanguo Wei; Yan Shi; Sheng Ding

    2013-01-01

    Stem cells,including both pluripotent stem cells and multipotent somatic stem cells,hold great potential for interrogating the mechanisms of tissue development,homeostasis and pathology,and for treating numerous devastating diseases.Establishment of in vitro platforms to faithfully maintain and precisely manipulate stem cell fates is essential to understand the basic mechanisms of stem cell biology,and to translate stem cells into regenerative medicine.Chemical approaches have recently provided a number of small molecules that can be used to control cell selfrenewal,lineage differentiation,reprogramming and regeneration.These chemical modulators have been proven to be versatile tools for probing stem cell biology and manipulating cell fates toward desired outcomes.Ultimately,this strategy is promising to be a new frontier for drug development aimed at endogenous stem cell modulation.

  14. Surface transport in the Ria de Vigo - Transport barriers in a tidal estuary with a complex geometry

    Science.gov (United States)

    Huhn, F.; von Kameke, A.; Montero, P.; Allen-Perkins, S.; Venancio, A.; Pérez-Muñuzuri, V.

    2012-04-01

    We study the submesoscale surface transport in the Ria de Vigo, NW Spain, an estuary with tidal and wind-driven circulation, analyzing the output of the coastal model MOHID with state-of-the-art Lagrangian methods, and comparing the results to drifter experiments. We extract Lagrangian Coherent Structures (LCS) as ridges in fields of the Finite-Time Lyapunov Exponent (FTLE) that can be identified with transport barriers. The LCS reveal the fundamental structure of the modelled circulation in the estaury that is a superposition of the tidal inflow and outflow, the wind-driven currents and the long-term drift on the shelf. In the Ria de Vigo, LCS are attached to prominent coastal boundaries, as islands or capes, indicating that the geometry of the flow patterns is dominated by bathymetry. Although the vertical flow which is not represented in the horizontal surface flow can be important at the coast, the found transport patterns can be seen as the surface footprint of the 3D circulation in the estaury. Comparing the trajectories of real surface drifters from four deployments to the computed transport barriers in different typical meteorological sitiations, we find that the drifter trajectories are in agreement with the different coherent water masses predicted by the model. The knowledge of the global transport patterns of water masses in this highly populated coastal region is indispensable for the assessment of the fate of contaminations, like possible oil spills or released waste water, but also for biological studies that deal with the drift of eggs and larvae of fish and other marine species, or investigate plankton blooms.

  15. Simulation of a relativistic heavy ions beam transport in the matter: contribution of the fragmentation process and biological implications; Simulation du transport d`un faisceau d`ions lourds relativistes dans la matiere: contribution du processus de fragmentation et implication sur le plan biologique

    Energy Technology Data Exchange (ETDEWEB)

    Ibnouzahir, M.

    1995-03-01

    The study of relativistic heavy ion collisions permit an approach of the properties of dense and not hadronic matter, and an analysis of the reaction mechanisms. Such studies are also interesting on the biological point of view, since there exist now well defined projects concerning the radiotherapy with high LET particles as neutrons, protons, heavy ions. It is thus necessary to have a good understanding of the processes which occur in the propagation of a relativistic heavy ion beam (E{>=} 100 A.MeV) in matter. We have elaborated a three dimensional transport code, using a Monte Carlo method, in order to describe the propagation of Ne and Ar ions in water. Violent nuclear collisions giving fragmentation process have been taken into account by use of the FREESCO program. We have tested the validity of our transport model and we show an important change of the energy deposition at the vicinity of the Bragg peak; such a distortion, due mainly to fragmentation reactions, is of a great interest for biological applications. (author).

  16. Randomness and Criticality in Biological Interactions

    OpenAIRE

    Grilli, Jacopo

    2015-01-01

    In this thesis we study from a physics perspective two problems related to biological interactions. In the first part of this thesis we consider ecological interactions, that shape ecosystems and determine their fate, and their relation with stability of ecosystems. Using random matrix theory we are able to identify the key aspect, the order parameters, determining the stability of large ecosystems. We then consider the problem of determining the persistence of a population living in a random...

  17. FATE Unified Modeling Method for Spent Nuclear Fuel and Sludge Processing, Shipping and Storage - 13405

    International Nuclear Information System (INIS)

    A unified modeling method applicable to the processing, shipping, and storage of spent nuclear fuel and sludge has been incrementally developed, validated, and applied over a period of about 15 years at the US DOE Hanford site. The software, FATETM, provides a consistent framework for a wide dynamic range of common DOE and commercial fuel and waste applications. It has been used during the design phase, for safety and licensing calculations, and offers a graded approach to complex modeling problems encountered at DOE facilities and abroad (e.g., Sellafield). FATE has also been used for commercial power plant evaluations including reactor building fire modeling for fire PRA, evaluation of hydrogen release, transport, and flammability for post-Fukushima vulnerability assessment, and drying of commercial oxide fuel. FATE comprises an integrated set of models for fluid flow, aerosol and contamination release, transport, and deposition, thermal response including chemical reactions, and evaluation of fire and explosion hazards. It is one of few software tools that combine both source term and thermal-hydraulic capability. Practical examples are described below, with consideration of appropriate model complexity and validation. (authors)

  18. Regional long-term model of radioactivity dispersion and fate in the Northwestern Pacific and adjacent seas: application to the Fukushima Dai-ichi accident

    International Nuclear Information System (INIS)

    The compartment model POSEIDON-R was modified and applied to the Northwestern Pacific and adjacent seas to simulate the transport and fate of radioactivity in the period 1945–2010, and to perform a radiological assessment on the releases of radioactivity due to the Fukushima Dai-ichi accident for the period 2011–2040. The model predicts the dispersion of radioactivity in the water column and in sediments, the transfer of radionuclides throughout the marine food web, and subsequent doses to humans due to the consumption of marine products. A generic predictive dynamic food-chain model is used instead of the biological concentration factor (BCF) approach. The radionuclide uptake model for fish has as a central feature the accumulation of radionuclides in the target tissue. The three layer structure of the water column makes it possible to describe the vertical structure of radioactivity in deep waters. In total 175 compartments cover the Northwestern Pacific, the East China and Yellow Seas and the East/Japan Sea. The model was validated from 137Cs data for the period 1945–2010. Calculated concentrations of 137Cs in water, bottom sediments and marine organisms in the coastal compartment, before and after the accident, are in close agreement with measurements from the Japanese agencies. The agreement for water is achieved when an additional continuous flux of 3.6 TBq y−1 is used for underground leakage of contaminated water from the Fukushima Dai-ichi NPP, during the three years following the accident. The dynamic food web model predicts that due to the delay of the transfer throughout the food web, the concentration of 137Cs for piscivorous fishes returns to background level only in 2016. For the year 2011, the calculated individual dose rate for Fukushima Prefecture due to consumption of fishery products is 3.6 μSv y−1. Following the Fukushima Dai-ichi accident the collective dose due to ingestion of marine products for Japan increased in 2011 by a factor

  19. Investigating the Toxicity and Environmental Fate of Graphene Nanomaterials

    Science.gov (United States)

    The Hersam Laboratory at Northwestern University works with the Center for Environmental Implications of Nanotechnology and the United States Environmental Protection Agency to study the toxicity and environmental fate of emergent nanomaterials, specifically carbon-based nanomate...

  20. Origin and fate of surface drift in the oceanic convergence zones of the eastern Pacific

    Science.gov (United States)

    Maes, Christophe; Blanke, Bruno; Martinez, Elodie

    2016-04-01

    This study investigates the structure and intensity of the surface pathways connecting to and from the central areas of the large-scale convergence regions of the eastern Pacific Ocean. Surface waters are traced with numerical Lagrangian particles transported in the velocity field of three different ocean models with horizontal resolutions that range from ¼° to 1/32°. The connections resulting from the large-scale convergent Ekman dynamics agree qualitatively but are strongly modulated by eddy variability that introduces meridional asymmetry in the amplitude of transport. Lagrangian forward-in-time integrations are used to analyze the fate of particles originating from the central regions of the convergence zones and highlight specific outflows not yet reported for the southeastern Pacific when using the currents at the highest resolutions (1/12° and 1/32°). The meridional scales of these outflows are comparable to the characteristic width of the fine-scale striation of mean currents.

  1. Fate of virginiamycin through the fuel ethanol production process.

    Science.gov (United States)

    Bischoff, Kenneth M; Zhang, Yanhong; Rich, Joseph O

    2016-05-01

    Antibiotics are frequently used to prevent and treat bacterial contamination of commercial fuel ethanol fermentations, but there is concern that antibiotic residues may persist in the distillers grains coproducts. A study to evaluate the fate of virginiamycin during the ethanol production process was conducted in the pilot plant facilities at the National Corn to Ethanol Research Center, Edwardsville, IL. Three 15,000-liter fermentor runs were performed: one with no antibiotic (F1), one dosed with 2 parts per million (ppm) of a commercial virginiamycin product (F2), and one dosed at 20 ppm of virginiamycin product (F3). Fermentor samples, distillers dried grains with solubles (DDGS), and process intermediates (whole stillage, thin stillage, syrup, and wet cake) were collected from each run and analyzed for virginiamycin M and virginiamycin S using a liquid chromatography-mass spectrometry method. Virginiamycin M was detected in all process intermediates of the F3 run. On a dry-weight basis, virginiamycin M concentrations decreased approximately 97 %, from 41 μg/g in the fermentor to 1.4 μg/g in the DDGS. Using a disc plate bioassay, antibiotic activity was detected in DDGS from both the F2 and F3 runs, with values of 0.69 μg virginiamycin equivalent/g sample and 8.9 μg/g, respectively. No antibiotic activity (process intermediate samples from the F2 run. These results demonstrate that low concentrations of biologically active antibiotic may persist in distillers grains coproducts produced from fermentations treated with virginiamycin.

  2. Formation, fate and leaching of chloroform in coniferous forest soils

    International Nuclear Information System (INIS)

    Research highlights: → Chloroform may be formed in coniferous forest soil. → The formed chloroform may enter the groundwater in μg/L concentrations. → Clear seasonal patterns in chloroform formation in soil are observed. → Sorption and degradation affects the fate of chloroform in forest soil. - Abstract: Chloroform is a common groundwater pollutant but also a natural compound in forest ecosystems. Leaching of natural chloroform from forest soil to groundwater was followed by regular analysis of soil air and groundwater from multilevel wells at four different sites in Denmark for a period of up to 4 a. Significant seasonal variation in chloroform was observed in soil air 0.5 m below surface ranging at one site from 120 ppb by volume in summer to 20 ppb during winter. With depth, the seasonal variation diminished gradually, ranging from 30 ppb in summer to 20 ppb during winter, near the groundwater table. Chloroform in the shallowest groundwater ranged from 0.5-1.5 μg L-1 at one site to 2-5 μg L-1 at another site showing no clear correlation with season. Comparing changes in chloroform in soil air versus depth with on-site recorded meteorological data indicated that a clear relationship appears between rain events and leaching of chloroform. Chloroform in top soil air co-varied with CO2 given a delay of 3-4 weeks providing evidence for its biological origin. This was confirmed during laboratory incubation experiments which further located the fermentation layer as the most chloroform producing soil horizon. Sorption of chloroform to soils, examined using 14C-CHCl3, correlated with organic matter content, being high in the upper organic rich soils and low in the deeper more minerogenic soils. The marked decrease in chloroform in soil with depth may in part be due to microbial degradation which was shown to occur at all depths by laboratory tests using 14C-CHCl3.

  3. The aquatic fate of triclopyr in whole-pond treatments.

    Science.gov (United States)

    Petty, D G; Skogerboe, J G; Getsinger, K D; Foster, D R; Houtman, B A; Fairchild, J F; Anderson, L W

    2001-09-01

    The aquatic fate of the triethylamine salt formulation of triclopyr (3,5,6-trichloro-2-pyridinyloxyacetic acid) was determined in whole-pond applications in closed (no water exchange) systems in California, Missouri and Texas in two studies conducted in 1995 and 1996. These studies determined dissipation rates of triclopyr and its principal metabolites, 3,5,6-trichloropyridinol (TCP) and 3,5,6-trichloro-2-methoxypridine (TMP) in water, sediment and finfish. Ponds at each site containing a healthy biological community were treated at 2.5 mg AE litre-1 triclopyr. Water and sediment samples were collected through 12 weeks post-treatment, and non-target animals were collected through 4 weeks post-treatment. Dissipation rates for triclopyr, TCP and TMP were similar at each of the study sites, despite differences in weather, water quality, biotic community, light transmission and geographic location. Half-lives of triclopyr in water ranged from 5.9 to 7.5 days, while those of TCP and TMP ranged from 4 to 8.8 and 4 to 10 days, respectively. Levels of triclopyr and TCP declined in sediments at half-lives ranging from 2.8 to 4.6 days and 3.8 to 13.3 days, respectively. No TMP was detected in sediment. Triclopyr and TCP cleared from fish in relation to concentrations found in the water column. TMP levels in fish were generally an order of magnitude higher than levels of triclopyr and TCP, particularly in the visceral portion of the animals. No adverse effects on water quality or on the non-target biotic community were found following triclopyr applications. Results of these studies were comparable to those of triclopyr dissipation studies conducted in reservoirs, lakes and riverine systems in Georgia, Florida, Minnesota and Washington, indicating that the degradation and dissipation of triclopyr and its metabolites are similar in representative systems throughout the USA. PMID:11561400

  4. Modelling the fate of organic micropollutants in stormwater ponds

    OpenAIRE

    Vezzaro, Luca; Eriksson, Eva; Ledin, Anna; Mikkelsen, Peter Steen

    2011-01-01

    Urban water managers need to estimate the potential removal of organic micropollutants (MP) in stormwater treatment systems to support MP pollution control strategies. This study documents how the potential removal of organic MP in stormwater treatment systems can be quantified by using multimedia models. The fate of four different MP in a stormwater retention pond was simulated by applying two steady-state multimedia fate models (EPI Suite and SimpleBox) commonly applied in chemical risk ass...

  5. Fate of adsorbable micropollutants through sludge drying and composting processes

    OpenAIRE

    Besnault, S.; Martin Ruel, S.; Choubert, JM.; Budzinski, H.; Miege, C.; Esperanza, M.; Noyon, N.; Garnaud, S.; Coquery, M.

    2012-01-01

    The objective of the paper was to evaluate the fate of 79 adsorbed micropollutants through 9 sludge treatment processes. A specific sampling strategy was applied to follow a “batch” of sludge through the treatment (inlet and outlet sludge, intermediary mixture for some processes such as composting and condensates). Mass balances were established to calculate micropollutants removal efficiencies and the fate of the substances through these facilities was evaluated. In order to limi...

  6. Assessing the fate of radioactive nickel in cultivated soil cores

    International Nuclear Information System (INIS)

    Parameters regarding fate of 63Ni in the soil-plant system (soil: solution distribution coefficient, Kd and soil plant concentration ratio, CR) are mostly determined in controlled pot experiments or from simple models involving a limited set of soil parameters. However, as migration of pollutants in soil is strongly linked to the water migration, variation of soil structure in the field and seasonal variation of evapotranspiration will affect these two parameters. The aim of this work was to explore to what extent the downward transfer of 63Ni and its uptake by plants from surface-contaminated undisturbed soil cores under cultivation can be explained by isotopic dilution of this radionuclide in the pool of stable Ni of soils. Undisturbed soil cores (50 cm x 50 cm) were sampled from a brown rendzina (Rendzic Leptosol), a colluvial brown soil (Fluvic Cambisol) and an acidic brown soil (Dystric Cambisol) using PVC lysimeter tubes (three lysimeters sampled per soil type). Each core was equipped with a leachate collector. Cores were placed in a greenhouse and maize (DEA, Pioneer) was sown. After 44 days, an irrigation was simulated at the core surfaces to supply 10 000 Bq 63NiCl2. Maize was harvested 135 days after 63Ni input and radioactivity determined in both vegetal and water samples. Effective uptake of 63Ni by maize was calculated for leaves and kernels. Water drainage and leaching of 63Ni were monitored over the course of the experiment. Values of Kd in surface soil samples were calculated from measured parameters of isotopic exchange kinetics. Results confirmed that 63Ni was strongly retained at the soil surface. Prediction of the 63Ni downward transfer could not be reliably assessed using the Kd values, since the soil structure, which controls local water fluxes, also affected both water and Ni transport. In terms of 63Ni plant uptake, the effective uptake in undisturbed soil cores is controlled by isotope dilution as previously shown at the pot experiment

  7. Zinc fate in animal husbandry systems.

    Science.gov (United States)

    Romeo, A; Vacchina, V; Legros, S; Doelsch, E

    2014-11-01

    Zinc (Zn) is considered in animal production systems as both an essential nutrient and a possible pollutant. While it is generally supplemented at low levels in animal diets, with less than 200 mg kg(-1) in complete feeds, it is under scrutiny due to potential accumulation in the environment. This explains why international regulations limit maximum supplementation levels in animal feeds in a stricter way. This article gives an overview of the current knowledge on the fate of zinc in animal production systems, from animal diets to animal wastes. Some analytical methods can be used for the quantification and qualification of Zn chemical forms: X-ray crystallography, electrospray tandem mass spectrometry, separation techniques, hyphenated techniques… Analysis of chelated forms issued from complex matrices, like hydrolysed proteins, remains difficult, and the speciation of Zn in diluted carriers (premix and feed) is a challenge. Our understanding of Zn absorption has made progress with recent research on ZnT/Zip families and metallothioneins. However, fine-tuned approaches towards the nutritional and metabolic interactions for Zn supplementation in farm conditions still require further studies. The speciation of zinc in pig manure and poultry litter has been a priority as monogastric animals are usually raised under intensive conditions and fed with high quantities of trace minerals, leading to high animal density and elevated quantities of zinc from animal wastes.

  8. Proliferating cell nuclear antigen in neutrophil fate.

    Science.gov (United States)

    Witko-Sarsat, Véronique; Ohayon, Delphine

    2016-09-01

    The life span of a neutrophil is a tightly regulated process as extended survival is beneficial for pathogen elimination and cell death necessary to prevent cytotoxic content release from activated neutrophils at the inflammatory site. Therefore, the control between survival and death must be a dynamic process. We have previously described that proliferating cell nuclear antigen (PCNA) which is known as a nuclear protein pivotal in DNA synthesis, is a key element in controlling neutrophil survival through its association with procaspases. Contrary to the dogma which asserted that PCNA has a strictly nuclear function, in mature neutrophils, PCNA is present exclusively within the cytosol due to its nuclear export at the end of the granulocytic differentiation. More recent studies are consistent with the notion that the cytosolic scaffold of PCNA is aimed at modulating neutrophil fate rather than simply preventing death. Ultimately, targeting neutrophil survival might have important applications not just in the field of immunology and inflammation, but also in hematology and transfusion. The neutrophil emerges as a unique and powerful cellular model to unravel the basic mechanisms governing the cell cycle-independent functions of PCNA and should be considered as a leader of the pack. PMID:27558345

  9. The Fate of Unstable Gauge Flux Compactifications

    CERN Document Server

    Burgess, C P; Zavala, I

    2009-01-01

    Fluxes are widely used to stabilise extra dimensions, but if they arise within a non-abelian gauge sector they are often unstable. We seek the fate of this instability, focussing on the simplest examples: sphere-monopole compactifications in six dimensions. Without gravity most non-abelian monopoles are unstable, decaying into the unique stable monopole in the same topological class. We show that the same is true in Einstein-YM systems, with the geometry adjusting accordingly: a Mink(d)xS2 geometry supported by an unstable monopole relaxes to an AdS(d)xS2. For 6D supergravity, the dilaton obstructs this simple evolution, acquiring a gradient and thus breaking some of the spacetime symmetries. We argue that it is the 4D symmetries that break, and examine several endpoint candidates. Oxidising the supergravity system into a higher-dimensional Einstein-YM monopole, we use the latter to guide us to the corresponding endpoint. The result is a singular Kasner-like geometry conformal to Mink(4)xS2. The solution has ...

  10. The fate of the earth. 5. ed.

    International Nuclear Information System (INIS)

    As a result of thorough investigations and based upon the latest findings of scientific research work, this book ''Fate of the Earth'' quite drastically illustrates the manifold and horrible ways mankind and numberless other creatures will have to suffer before perishing in the wake of the pollution of nature and atmosphere for an unforeseeable time, should it happen one day that even only part of the existing nuclear weapons potential of 20.000 megatons of TNT be used at any spot of this world. In view of this global threat, every one of us has to do his bit in trying to safeguard the future of our world. The author discusses all important scientific, political and moral perspectives to be taken into account not only by the superpowers but literally by all states and all people in the face of a possible nuclear holocaust. Presenting his doubts whether the concept of deterrence will in future suffice to prevent a third world war, he implores us, the inhabitants of this planet, to wake up and act before it will be too late. (orig./HSCH)

  11. Evolution and fate of very massive stars

    CERN Document Server

    Yusof, Norhasliza; Meynet, Georges; Crowther, Paul A; Ekstrom, Sylvia; Frischknecht, Urs; Georgy, Cyril; Kassim, Hasan Abu; Schnurr, Olivier; 10.1093/mnras/stt794

    2013-01-01

    There is observational evidence that supports the existence of Very Massive Stars in the local universe. First, very massive stars (Mini<=320 M) have been observed in the Large Magellanic Cloud . Second, there are observed SNe that bear the characteristics of Pair Creation Supernovae which have very massive stars as progenitors. The most promising candidate to date is SN2007bi. In order to investigate the evolution and fate of nearby very massive stars, we calculated a new grid of models for such objects, for solar, LMC and SMC metallicities, which covers the initial mass range from 120 to 500M. Both rotating and non-rotating models were calculated using the Geneva stellar evolution code and evolved until at least the end of helium burning and for most models until oxygen burning. Since very massive stars have very large convective cores during the Main-Sequence phase, their evolution is not so much affected by rotational mixing, but more by mass loss through stellar winds. Their evolution is never far fro...

  12. Observations on the Chinese idea of fate

    Directory of Open Access Journals (Sweden)

    Gunnar Sjöholm

    1967-02-01

    Full Text Available Throughout the history of Chinese religion, ideas of fate are present. The earliest forms of Chinese writing occur on thousands of tortoise shells found 65 years ago in the province of Honan. At that time inscriptions on bronze vessels from the first millennium B.C. were already known. But the new material was more difficult to interpret. The amount of material has grown since then: there are now about 100 000 inscribed shells and bones, some hundreds of whole tortoise shields with inscriptions as well as other archaeological material. One third of the signs has been deciphered. The inscriptions are mostly quite brief and contain oracle formulas. The people of the Shang-Yin dynasty (1500-1028 B.C. knew the useful and the beautiful. What did the oracle stand for? Did it represent something necessary? An oracular technique had been developed, "which consisted in touching shells or bones on one side with a little red-hot rod and interpreting according to certain patterns the cracks that arose on the other side as the answers of the ancestral spirits to the questions of the kings. After the consultation of the oracle the questions and often the answers were inscribed beside the cracks. Often also pure memoranda concerning weather, war expeditions etc. were inscribed.

  13. Effects of Natural Organic Matter on Stability, Transport and Deposition of Engineered Nano-particles in Porous Media

    Science.gov (United States)

    The interaction of nano-particles and organic substances, like natural organic matter, could have significant influence on the fate, transport and bioavailability of toxic substances. Natural organic matter (NOM) is a mixture of chemically complex polyelectrolytes with varying m...

  14. A general model for binary cell fate decision gene circuits with degeneracy: indeterminacy and switch behavior in the absence of cooperativity.

    Directory of Open Access Journals (Sweden)

    Mircea Andrecut

    Full Text Available BACKGROUND: The gene regulatory circuit motif in which two opposing fate-determining transcription factors inhibit each other but activate themselves has been used in mathematical models of binary cell fate decisions in multipotent stem or progenitor cells. This simple circuit can generate multistability and explains the symmetric "poised" precursor state in which both factors are present in the cell at equal amounts as well as the resolution of this indeterminate state as the cell commits to either cell fate characterized by an asymmetric expression pattern of the two factors. This establishes the two alternative stable attractors that represent the two fate options. It has been debated whether cooperativity of molecular interactions is necessary to produce such multistability. PRINCIPAL FINDINGS: Here we take a general modeling approach and argue that this question is not relevant. We show that non-linearity can arise in two distinct models in which no explicit interaction between the two factors is assumed and that distinct chemical reaction kinetic formalisms can lead to the same (generic dynamical system form. Moreover, we describe a novel type of bifurcation that produces a degenerate steady state that can explain the metastable state of indeterminacy prior to cell fate decision-making and is consistent with biological observations. CONCLUSION: The general model presented here thus offers a novel principle for linking regulatory circuits with the state of indeterminacy characteristic of multipotent (stem cells.

  15. Integrated Biological Control

    International Nuclear Information System (INIS)

    Biological control is any activity taken to prevent, limit, clean up, or remediate potential environmental, health and safety, or workplace quality impacts from plants, animals, or microorganisms. At Hanford the principal emphasis of biological control is to prevent the transport of radioactive contamination by biological vectors (plants, animals, or microorganisms), and where necessary, control and clean up resulting contamination. Other aspects of biological control at Hanford include industrial weed control (e.g.; tumbleweeds), noxious weed control (invasive, non-native plant species), and pest control (undesirable animals such as rodents and stinging insects; and microorganisms such as molds that adversely affect the quality of the workplace environment). Biological control activities may be either preventive (apriori) or in response to existing contamination spread (aposteriori). Surveillance activities, including ground, vegetation, flying insect, and other surveys, and apriori control actions, such as herbicide spraying and placing biological barriers, are important in preventing radioactive contamination spread. If surveillance discovers that biological vectors have spread radioactive contamination, aposteriori control measures, such as fixing contamination, followed by cleanup and removal of the contamination to an approved disposal location are typical response functions. In some cases remediation following the contamination cleanup and removal is necessary. Biological control activities for industrial weeds, noxious weeds and pests have similar modes of prevention and response

  16. Biological computation

    CERN Document Server

    Lamm, Ehud

    2011-01-01

    Introduction and Biological BackgroundBiological ComputationThe Influence of Biology on Mathematics-Historical ExamplesBiological IntroductionModels and Simulations Cellular Automata Biological BackgroundThe Game of Life General Definition of Cellular Automata One-Dimensional AutomataExamples of Cellular AutomataComparison with a Continuous Mathematical Model Computational UniversalitySelf-Replication Pseudo Code Evolutionary ComputationEvolutionary Biology and Evolutionary ComputationGenetic AlgorithmsExample ApplicationsAnalysis of the Behavior of Genetic AlgorithmsLamarckian Evolution Genet

  17. The Transport and Impact of Metal Nanoparticles in Soil

    Science.gov (United States)

    Dror, Ishai; Berkowitz, Brian

    2014-05-01

    The fate, transport and mobility of nanoparticles in soil are strongly dependent on environmental conditions. In this study we present the effect of soil properties on the transport of silver nanoparticles (AgNPs) in a set of laboratory column experiments, using different combinations of size fractions of a Mediterranean sandy clay soil. AgNPs are shown to have high mobility in soil with outlet relative concentrations ranging from 30% to 70%, depending on experimental conditions. The AgNP mobility through the column decreases when the fraction of smaller soil aggregates is larger. An early breakthrough pattern was found for the AgNP but not observed for AgNPs in pure quartz columns nor for bromide tracer in soil columns, suggesting that early breakthrough is related to the nature of AgNP transport in natural soils. Micro-CT and image analysis used to investigate structural features of the soil, suggest that soil aggregate size strongly affects AgNP transport in natural soil. These findings point to the importance of AgNP-soil chemical interactions as a retention mechanism, and demonstrate the need to employ natural soils rather than glass beads or quartz in representative experimental investigations. It is further noted that little is known about the possible effects of nanoparticles on soil chemical, physical and biological properties. Here we show that although copper oxide nanoparticles (nCuO) had little impact on the macroscopic properties of the soil, they did cause changes to humic substance structure and affected the soil bacterial community composition. In particular, the nCuO was found to have a strong effect on bacterial hydrolytic activity, oxidative potential, community composition and size in Bet-Dagan soil. These results indicate that CuO NPs are potentially harmful to soil environments. Furthermore, the results suggest that the clay fraction and organic matter in different soils interact with the nCuO and reduce its toxicity.

  18. Glycan Engineering for Cell and Developmental Biology

    Science.gov (United States)

    Griffin, Matthew E.; Hsieh-Wilson, Linda C.

    2016-01-01

    Cell-surface glycans are a diverse class of macromolecules that participate in many key biological processes, including cell-cell communication, development, and disease progression. Thus, the ability to modulate the structures of glycans on cell surfaces provides a powerful means not only to understand fundamental processes but also to direct activity and elicit desired cellular responses. Here, we describe methods to sculpt glycans on cell surfaces and highlight recent successes in which artificially engineered glycans have been employed to control biological outcomes such as the immune response and stem cell fate. PMID:26933739

  19. Fate of manufactured nanoparticles in environmental systems

    Science.gov (United States)

    Gelabert, A.; Sivry, Y.; Siron, V.; Akrout, A.; Ferrari, R.; Juillot, F.; Menguy, N.; Benedetti, M. F.

    2009-12-01

    Because of their specific physico-chemical properties, engineered nanoparticles (NPs) have become largely widespread in numerous industrial fields such as biomedicine, cosmetics, and material sciences. However, their growing use could possibly result in the release of various NPs amounts in environmental settings. Thus, an accurate understanding of their behaviour in natural systems is required, and of first importance is an estimation of their persistence and/or physico-chemical modifications since they can greatly alter their fate and bioavailability in the biogeosphere. The present study focuses on dissolution rate estimations for commercial NPs ZnO and TiO2 in natural waters (i.e. filtered Seine river water and seawater). Both NPs were used uncoated and coated with an organic polymer. Native NPs size and shape were investigated using TEM, and appeared as 20-50 nm spheroids, with an associated specific surface area of 37.5 and 57.6 m2/g for ZnO and TiO2, respectivelly. NPs dissolution rates were determined using both ultrafiltration (UF) and Donnan Membrane Techniques (DMT, [1]). The latter method allows a direct in-situ measurement of the free metal ion concentration only (here Zn2+), while the UF membrane small nominal pore size (approx. 2 nm) results in the separation of small inorganic complexes in addition to free metal ions. After a fast dissolution step reaching 1% of total zinc within the first hour for uncoated ZnO NPs in Seine water, precipitation of new mineral phases occurred with the formation of smithonite and hydrozincite as observed by XRD and TEM and confirmed by thermodynamic calculations (Visual Minteq). Interestingly, the behaviour of the coated ZnO NPs is slightly different since the initial dissolution step takes place during the first 72 hours, to reach up to 10% of the total zinc in our system. However, despite this difference in dissolution kinetics, both systems evolve similarly after 3 days, and they reach a steady state after

  20. Geochemical fate of arsenic in swine litter

    Science.gov (United States)

    Quazi, S.; Makris, K.; Sarkar, D.; Datta, R.; Punamiya, P.

    2007-12-01

    Swine diet is often supplemented by organoarsenicals, such as roxarsone to treat diseases and to promote growth. Recent data reported roxarsone degradation under anaerobic conditions in poultry litter, but no such data exist for swine wastes typically stored in unprotected lagoons in concentrated animal feeding operations (CAFOs). However, serious environmental health risk may arise upon significant arsenic (As) release into solution. The problem may be exacerbated under certain environmental conditions where organoarsenicals, such as roxarsone transform into the more toxic inorganic As, posing serious health risk to the surrounding ecosystem. The objective of this study were to analyze swine wastes collected from 19 randomly selected CAFOs in the USA for As concentrations, and to determine the geochemical fate of As in the swine waste suspensions. Swine wastes were analyzed for total-recoverable, total soluble, and water-extractable As, which were measured by ICP-MS. Speciation of As was performed following a well-established hyphenated technique using HPLC- ICPMS. Swine waste suspensions differed in solids contents; thus, the particulate matters with varying As concentrations were spiked with roxarsone and incubated under dark/light and aerobic/anaerobic conditions. Findings show the prevalence of inorganic As [As(V)] in swine waste suspension solutions. Roxarsone underwent degradation to both organoarsenicals, such as p-ASA, as well as inorganic arsenate and to a number of unidentified metabolites. Roxarsone degradation kinetics was influenced by the solids content and the air conditions (anaerobic/aerobic) of the swine waste suspensions. Maximum degradation rates were observed under anaerobic conditions, in suspensions which were low in solids content. Roxarsone degradation was primarily microbially-mediated, but in certain cases abiotic degradation was also observed, which were significantly slower.

  1. Liposome reconstitution and transport assay for recombinant transporters.

    Science.gov (United States)

    Johnson, Zachary Lee; Lee, Seok-Yong

    2015-01-01

    Secondary active transporters are responsible for the cellular uptake of many biologically important molecules, including neurotransmitters, nutrients, and drugs. Because of their physiological and clinical importance, a method for assessing their transport activity in vitro is necessary to gain a better understanding of how these transporters function at the molecular level. In this chapter, we describe a protocol for reconstituting the concentrative nucleoside transporter from Vibrio cholerae into proteoliposomes. We then describe a radiolabeled substrate uptake assay that can be used to functionally characterize the transporter. These methods are relatively common and can be applied to other secondary active transporters, with or without some modification.

  2. A workshop model simulating fate and effect of drilling muds and cuttings on benthic communities

    Science.gov (United States)

    Auble, Gregor T.; Andrews, Austin K.; Hamilton, David B.; Roelle, James E.; Shoemaker, Thomas G.

    1984-01-01

    , such as might be encountered in the Gulf of Mexico; and (4) a very deep (1,000 m) environment, such as might be encountered on the Atlantic slope. The focus of the modeling effort was on the connection of a reasonable representation of physical fate to the biological responses of populations, rather than on highly detailed representations of individual processes. For example, the calculations of physical fate are not as detailed as those in the recently published model of Brandsma et al. (1983). The value of the model described herein is in the broad scope of processes that are explicitly represented and linked together. The model cannot be considered to produce reliable predictions of the quantitative impacts of discharged drilling fluids and cuttings on biological populations at a particular site. Limitations of the model in predicting integrated fate and effects can be traced to three general areas: level of refinement of the algorithms used in the model; lack of understanding of the processes determining fate and effects; and parameter and data values. Despite the limitations, several qualitative conclusions concerning both potential impacts and the importance of various remaining data gaps can be drawn from the modeling effort. These include: (1) Simple, unequivocal conclusions about fate and effects across geographical regions and drilling operations are difficult, if not misleading, due to the large amount of variability in characteristics of discharged materials (e.g., oil content and toxicity), discharge conditions (e.g., duration of drilling operations), physical environments (e.g., water depth, current direction, and sediment disturbance regimes), and biological communities (e.g., intrinsic growth rates). Different combinations of these characteristics can result in substantial differences in simulated environmental fate and biological effects. For examples, simulated recovery in some high-energy environments occurs within months after the cessation of

  3. Geochemical, hydrological, and biological cycling of energy residual. Research plan

    International Nuclear Information System (INIS)

    Proposed research goals and specific research areas designed to provide a base of fundamental scientific information so that the geochemical, hydrological, and biophysical mechanisms that contribute to the transport and long term fate of energy residuals in natural systems can be understood are described. Energy development and production have resulted in a need for advanced scientific information on the geochemical transformations, transport rates, and potential for bioaccumulation of contaminants in subsurface environments

  4. Fate of Carbamazepine during Water Treatment

    DEFF Research Database (Denmark)

    Kosjek, T.; Andersen, Henrik Rasmus; Kompare, Boris;

    2009-01-01

    of acridone, hydroxy-(9H,10H)-acridine-9-carbaldehyde, acridone-N-carbaldehyde, and 1-(2-benzaldehyde)-(1H,3H-quinazoline-2,4-dione, while biological breakdown of acridine yielded acridone. In parallel, the transformation product iminostilbene was observed during sample analysis. In addition,this study...

  5. Identification and Quantification of Processes Affecting the Fate of Ethanol-Blended Fuel in the Subsurface

    Science.gov (United States)

    Devries, J. M.; Mayer, K. U.

    2015-12-01

    At present, the oil and gas industry distributes gasoline with an ethanol content of up to 10% (E10) to the consumer. However, ethanol advocates are promoting gasoline blends with higher ethanol content to be introduced into the market (e.g., E20, corresponding to an ethanol content of 20%). The likelihood of unintended fuel releases with elevated ethanol concentrations through surficial spills or from underground storage systems will therefore increase. A particular concern is the increased rate of CH4 and CO2 production as the spill biodegrades, which is believed to be associated with the increased ethanol content in the fuel. Consequently, high gas generation rates associated with ethanol-blended fuels may amplify the risk of vapor intrusion of CH4 and BTEX into basements or other subsurface structures that may be nearby. A comprehensive and comparative study on the fate of higher concentration ethanol-blended fuels in the subsurface has not been conducted to date. The present study focuses on determining the fate of ethanol blended fuels in the subsurface through a series of controlled and instrumented laboratory column experiments. The experiments compare the behavior of pure gasoline with that of ethanol-blended fuels for different soil types (sand and silt) in columns 2 meters tall and 30cm in diameter. The column experiments focus on the quantification of gas generation by volatilization and biodegradation and 1-D vertical fate and transport of CO2, CH4, benzene and toluene through the vadose zone. The fuel blends have been injected into the lower third of the columns and gas composition and fluxes within the column are being monitored over time. The goal of this study is to contribute to the scientific foundation that will allow gauging the level of risk and the need for remediation at fuel spill sites with higher ethanol blends.

  6. Control of stem cell fate by engineering their micro andnanoenvironment

    Institute of Scientific and Technical Information of China (English)

    Michelle F Griffin; Peter E Butler; Alexander M Seifalian; Deepak M Kalaskar

    2015-01-01

    Stem cells are capable of long-term self-renewal anddifferentiation into specialised cell types, making theman ideal candidate for a cell source for regenerativemedicine. The control of stem cell fate has become amajor area of interest in the field of regenerative medicineand therapeutic intervention. Conventional methodsof chemically inducing stem cells into specific lineagesis being challenged by the advances in biomaterialtechnology, with evidence highlighting that materialproperties are capable of driving stem cell fate. Materialsare being designed to mimic the clues stem cells receivein their in vivo stem cell niche including topographicaland chemical instructions. Nanotopographical clues thatmimic the extracellular matrix (ECM) in vivo have shownto regulate stem cell differentiation. The delivery of ECMcomponents on biomaterials in the form of short peptidessequences has also proved successful in directing stem celllineage. Growth factors responsible for controlling stemcell fate in vivo have also been delivered via biomaterialsto provide clues to determine stem cell differentiation. Analternative approach to guide stem cells fate is to providegenetic clues including delivering DNA plasmids andsmall interfering RNAs via scaffolds. This review, aims toprovide an overview of the topographical, chemical andmolecular clues that biomaterials can provide to guidestem cell fate. The promising features and challenges ofsuch approaches will be highlighted, to provide directionsfor future advancements in this exciting area of stem celltranslation for regenerative medicine.

  7. Exploring guanidinoglycoside molecular transporters

    OpenAIRE

    Dix, Andrew Vincent

    2011-01-01

    Guanidinium-rich molecular transporters have been shown to deliver otherwise non-permeable biologically relevant cargo into cells. While many such transporters have been reported, the studies reported here focus on guanidinoglycosides, which have been shown to permeate the cell-membrane in a heparan sulfate-dependent manner. In attempt to promote a cooperative interaction with cell- surface heparan sulfate, dimeric guanidinoglycosides were synthesized and studied for their cellular uptake pro...

  8. Fate of Organic Micropollutants during Hydrothermal Carbonization

    Science.gov (United States)

    Weiner, B.; Baskyr, I.; Pörschmann, J.; Kopinke, F.-D.

    2012-04-01

    contaminated biomass. Chlorinated aromatic compounds are not fully degraded during HTC. Therefore, the addition of catalysts and reagents for a possible reduction has been studied. Zero-valent environmentally acceptable metals, such as Fe or Si, are presented as potential additives for the dechlorination of chloronaphthalene as a representative of chloroaromatics. Furthermore, when using municipal household waste, such as the 'organic' bin, or gardening greens as biomass educts, these materials often contain traces of synthetic plastics, which can lead to problems during waste incineration. Initial studies on the fate of synthetic polymers will also be presented.

  9. The final fate of planetary systems

    Science.gov (United States)

    Gaensicke, Boris

    2015-12-01

    The discovery of the first extra-solar planet around a main-sequence star in 1995 has changed the way we think about the Universe: our solar system is not unique. Twenty years later, we know that planetary systems are ubiquitous, orbit stars spanning a wide range in mass, and form in an astonishing variety of architectures. Yet, one fascinating aspect of planetary systems has received relatively little attention so far: their ultimate fate.Most planet hosts will eventually evolve into white dwarfs, Earth-sized stellar embers, and the outer parts of their planetary systems (in the solar system, Mars and beyond) can survive largely intact for billions of years. While scattered and tidally disrupted planetesimals are directly detected at a small number of white dwarfs in the form infrared excess, the most powerful probe for detecting evolved planetary systems is metal pollution of the otherwise pristine H/He atmospheres.I will present the results of a multi-cycle HST survey that has obtained COS observations of 136 white dwarfs. These ultraviolet spectra are exquisitely sensitive to the presence of metals contaminating the white atmosphere. Our sophisticated model atmosphere analysis demonstrates that at least 27% of all targets are currently accreting planetary debris, and an additional 29% have very likely done so in the past. These numbers suggest that planet formation around A-stars (the dominant progenitors of today's white dwarf population) is similarly efficient as around FGK stars.In addition to post-main sequence planetary system demographics, spectroscopy of the debris-polluted white dwarf atmospheres provides a direct window into the bulk composition of exo-planetesimals, analogous to the way we use of meteorites to determine solar-system abundances. Our ultraviolet spectroscopy is particularly sensitive to the detection of Si, a dominant rock-forming species, and we identify up to ten additional volatile and refractory elements in the most strongly

  10. UVCB substances: methodology for structural description and application to fate and hazard assessment.

    Science.gov (United States)

    Dimitrov, Sabcho D; Georgieva, Denitsa G; Pavlov, Todor S; Karakolev, Yordan H; Karamertzanis, Panagiotis G; Rasenberg, Mike; Mekenyan, Ovanes G

    2015-11-01

    Substances of unknown or variable composition, complex reaction products, or biological materials (UVCBs) have been conventionally described in generic terms. Commonly used substance identifiers are generic names of chemical classes, generic structural formulas, reaction steps, physical-chemical properties, or spectral data. Lack of well-defined structural information has significantly restricted in silico fate and hazard assessment of UVCB substances. A methodology for the structural description of UVCB substances has been developed that allows use of known identifiers for coding, generation, and selection of representative constituents. The developed formats, Generic Simplified Molecular-Input Line-Entry System (G SMILES) and Generic Graph (G Graph), address the need to code, generate, and select representative UVCB constituents; G SMILES is a SMILES-based single line notation coding fixed and variable structural features of UVCBs, whereas G Graph is based on a workflow paradigm that allows generation of constituents coded in G SMILES and end point-specific or nonspecific selection of representative constituents. Structural description of UVCB substances as afforded by the developed methodology is essential for in silico fate and hazard assessment. Data gap filling approaches such as read-across, trend analysis, or quantitative structure-activity relationship modeling can be applied to the generated constituents, and the results can be used to assess the substance as a whole. The methodology also advances the application of category-based data gap filling approaches to UVCB substances.

  11. Behaviour and fate of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in drinking water treatment: a review.

    Science.gov (United States)

    Rahman, Mohammad Feisal; Peldszus, Sigrid; Anderson, William B

    2014-03-01

    This article reviews perfluoroalkyl and polyfluoroalkyl substance (PFAS) characteristics, their occurrence in surface water, and their fate in drinking water treatment processes. PFASs have been detected globally in the aquatic environment including drinking water at trace concentrations and due, in part, to their persistence in human tissue some are being investigated for regulation. They are aliphatic compounds containing saturated carbon-fluorine bonds and are resistant to chemical, physical, and biological degradation. Functional groups, carbon chain length, and hydrophilicity/hydrophobicity are some of the important structural properties of PFASs that affect their fate during drinking water treatment. Full-scale drinking water treatment plant occurrence data indicate that PFASs, if present in raw water, are not substantially removed by most drinking water treatment processes including coagulation, flocculation, sedimentation, filtration, biofiltration, oxidation (chlorination, ozonation, AOPs), UV irradiation, and low pressure membranes. Early observations suggest that activated carbon adsorption, ion exchange, and high pressure membrane filtration may be effective in controlling these contaminants. However, branched isomers and the increasingly used shorter chain PFAS replacement products may be problematic as it pertains to the accurate assessment of PFAS behaviour through drinking water treatment processes since only limited information is available for these PFASs. PMID:24216232

  12. Cancer becomes wasteful: emerging roles of exosomes in cell-fate determination

    Directory of Open Access Journals (Sweden)

    Franz Wendler

    2013-09-01

    Full Text Available Extracellular vesicles (EVs, including exosomes, have been widely recognized for their role in intercellular communication of the immune response system. In the past few years, significance has been given to exosomes in the induction and modulation of cell-fate-inducing signalling pathways, such as the Hedgehog (Hh, Wnts, Notch, transforming growth factor (TGF-β, epidermal growth factor (EGF and fibroblast growth factor (FGF pathways, placing them in the wider context of development and also of cancer. These protein families induce signalling cascades responsible for tissue specification, homeostasis and maintenance. Exosomes contribute to cell-fate signal secretion, and vice versa exosome secretion can be induced by these proteins. Interestingly, exosomes can also transfer their mRNA to host cells or modulate the signalling pathways directly by the removal of downstream effector molecules from the cell. Surprisingly, much of what we know about the function of exosomes in cell determination is gathered from pathological transformed cancer cells and wound healing while data about their biogenesis and biology in normal developing and adult tissue lag behind. In this report, we will summarize some of the published literature and point to current advances and questions in this fast-developing topic. In a brief foray, we will also update and shortly discuss their potential in diagnosis and targeted cancer treatment.

  13. Behaviour and fate of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in drinking water treatment: a review.

    Science.gov (United States)

    Rahman, Mohammad Feisal; Peldszus, Sigrid; Anderson, William B

    2014-03-01

    This article reviews perfluoroalkyl and polyfluoroalkyl substance (PFAS) characteristics, their occurrence in surface water, and their fate in drinking water treatment processes. PFASs have been detected globally in the aquatic environment including drinking water at trace concentrations and due, in part, to their persistence in human tissue some are being investigated for regulation. They are aliphatic compounds containing saturated carbon-fluorine bonds and are resistant to chemical, physical, and biological degradation. Functional groups, carbon chain length, and hydrophilicity/hydrophobicity are some of the important structural properties of PFASs that affect their fate during drinking water treatment. Full-scale drinking water treatment plant occurrence data indicate that PFASs, if present in raw water, are not substantially removed by most drinking water treatment processes including coagulation, flocculation, sedimentation, filtration, biofiltration, oxidation (chlorination, ozonation, AOPs), UV irradiation, and low pressure membranes. Early observations suggest that activated carbon adsorption, ion exchange, and high pressure membrane filtration may be effective in controlling these contaminants. However, branched isomers and the increasingly used shorter chain PFAS replacement products may be problematic as it pertains to the accurate assessment of PFAS behaviour through drinking water treatment processes since only limited information is available for these PFASs.

  14. Cranial osteopathy: its fate seems clear

    OpenAIRE

    Hartman Steve E

    2006-01-01

    Abstract Background According to the original model of cranial osteopathy, intrinsic rhythmic movements of the human brain cause rhythmic fluctuations of cerebrospinal fluid and specific relational changes among dural membranes, cranial bones, and the sacrum. Practitioners believe they can palpably modify parameters of this mechanism to a patient's health advantage. Discussion This treatment regime lacks a biologically plausible mechanism, shows no diagnostic reliability, and offers little ho...

  15. Fate of mercury in the Arctic (FOMA)

    DEFF Research Database (Denmark)

    Skov, H.; Christensen, J.; Asmund, G.;

    This report is the final reporting of the project FONA, funded by the Danish Environmental Protection Agency with means from the MIKA/DANCEA funds for Environmental Support to the Arctic Region. The aim of the project is to study the intercompartment mercury transport chain in the arctic area. From...... atmospheric deposition of mercury on sea surfaces to uptake in marine organisms, bio-accumulation, and finally mercury levels in mammals. The studies in the project are focused on the behaviour of mercury during the spring period where special phenomena lead to an enhanced deposition of mercury in the Arctic...... environment, at a time where the marine ecosystem is particularly active. The studies also include a comprehensive time trend study of mercury in top carnivore species. Each of these studies contributes towards establishing the knowledge necessary to develop a general model for transport and uptake of mercury...

  16. Mathematical modeling of biological processes

    CERN Document Server

    Friedman, Avner

    2014-01-01

    This book on mathematical modeling of biological processes includes a wide selection of biological topics that demonstrate the power of mathematics and computational codes in setting up biological processes with a rigorous and predictive framework. Topics include: enzyme dynamics, spread of disease, harvesting bacteria, competition among live species, neuronal oscillations, transport of neurofilaments in axon, cancer and cancer therapy, and granulomas. Complete with a description of the biological background and biological question that requires the use of mathematics, this book is developed for graduate students and advanced undergraduate students with only basic knowledge of ordinary differential equations and partial differential equations; background in biology is not required. Students will gain knowledge on how to program with MATLAB without previous programming experience and how to use codes in order to test biological hypothesis.

  17. Cell fate control in the developing central nervous system

    Energy Technology Data Exchange (ETDEWEB)

    Guérout, Nicolas; Li, Xiaofei; Barnabé-Heider, Fanie, E-mail: Fanie.Barnabe-Heider@ki.se

    2014-02-01

    The principal neural cell types forming the mature central nervous system (CNS) are now understood to be diverse. This cellular subtype diversity originates to a large extent from the specification of the earlier proliferating progenitor populations during development. Here, we review the processes governing the differentiation of a common neuroepithelial cell progenitor pool into mature neurons, astrocytes, oligodendrocytes, ependymal cells and adult stem cells. We focus on studies performed in mice and involving two distinct CNS structures: the spinal cord and the cerebral cortex. Understanding the origin, specification and developmental regulators of neural cells will ultimately impact comprehension and treatments of neurological disorders and diseases. - Highlights: • Similar mechanisms regulate cell fate in different CNS cell types and structures. • Cell fate regulators operate in a spatial–temporal manner. • Different neural cell types rely on the generation of a diversity of progenitor cells. • Cell fate decision is dictated by the integration of intrinsic and extrinsic signals.

  18. Cell fate determination by ubiquitin-dependent regulation of translation

    Science.gov (United States)

    Werner, Achim; Iwasaki, Shintaro; McGourty, Colleen; Medina-Ruiz, Sofia; Teerikorpi, Nia; Fedrigo, Indro; Ingolia, Nicholas T.; Rape, Michael

    2015-01-01

    Metazoan development depends on accurate execution of differentiation programs that allow pluripotent stem cells to adopt specific fates 1. Differentiation requires changes to chromatin architecture and transcriptional networks, yet whether other regulatory events support cell fate determination is less well understood. Here, we have identified the vertebrate-specific ubiquitin ligase CUL3KBTBD8 as an essential regulator of neural crest specification. CUL3KBTBD8 monoubiquitylates NOLC1 and its paralog TCOF1, whose mutation underlies the neurocristopathy Treacher Collins Syndrome 2,3. Ubiquitylation drives formation of a TCOF1-NOLC1 platform that connects RNA polymerase I with ribosome modification enzymes and remodels the translational program of differentiating cells in favor of neural crest specification. We conclude that ubiquitin-dependent regulation of translation is an important feature of cell fate determination. PMID:26399832

  19. Assessing the Occurrence, Persistence, and Fate of Natural and Synthetic Steroid Estrogens in Vernal Pools

    Science.gov (United States)

    Mina, O.

    2015-12-01

    The presence of natural and synthetic estrogens in treated wastewater used for irrigation of agricultural fields poses a potential risk to surface water ecosystems. While a large number of recent studies have investigated the occurrence, fate, and transport of estrogens in the environment, the vast majority of these studies have focused on the fate of estrogens in streams and rivers. However, no studies have been conducted assessing the occurrence, persistence, and fate of estrogens in impacted sensitive aquatic ecosystems such as vernal pools. This is of particular importance because vernal pools serve as critical breeding habitat for amphibians, which are known to be sensitive to the presence of endocrine disrupting compounds. A spray irrigation system was implemented over 50 years ago at Penn State's "Living Filter" as an alternative to discharging treated wastewater to a high quality trout stream. This system introduces all of Penn State's treated wastewater onto approximately 250 ha of agricultural and forested land at a rate of ~5 cm/ha/week. More than a dozen vernal pools are impacted by this wastewater irrigation, with some ponds adjacent to irrigation laterals receiving direct inputs of the treated wastewater. The goal of this study was to assess the impact of these weekly irrigation activities on the occurrence, persistence, and fate of estrogens (17α- and 17β-estradiol, estrone, estriol, and ethinylestradiol) in 3 vernal pools during an 8-week field study. The spring 2015 study period coincided with wood frog breeding and metamorphosis. Irrigation wastewater was collected weekly and water samples near the sediment-water interface in each vernal pool were collected daily. Real-time monitoring stations continuously recorded the temperature, pH, redox potential, DO, EC, and water level at each pool. Nearly 100% of the daily samples (n>130) collected contained estrogens, and the concentrations were several times higher compared to the wastewater

  20. The Fate of Hydrocarbon Pollution in Kebnekaise, Arctic Sweden

    Science.gov (United States)

    Rosqvist, G. N.; Jarjso, J.; Clason, C.; Jansson, P.; Karlin, T.

    2013-12-01

    A C-130J-30 Super Hercules plane crashed into the west-facing wall of the Kebnekaise mountain (2103 m), Arctic Sweden, on March 15th 2012. When starting from Evenes, Narvik, Norway, the aircraft had 14100 l fuel, 50 l hydraulic oil and 170 l motor oil onboard. Best estimates are that at least 12 000 l of fuel was sprayed over the mountain most of which was buried together with the wreck in a huge snow avalanche that was triggered by the impact in a NW facing cirque on Rabots glacier between ca 1600 and 2000 m. Fuel decontamination was not possible because of the extreme impact site conditions. The Hercules airplane was fueled with JET A-1 which is a hydrocarbon product in the Kerosene/Jet Fuel category consisting of sweetened kerosene and hydrotreated light distillates. The major components of all 'kerosene's' are branched- and straight-chain paraffins and naphthenes (cycloparaffins or cycloalkanes), which normally account for 70% by volume. Aromatic hydrocarbons, such as alkyl benzenes (single ring) and alkylnaphthalenes (double ring) do not exceed 25 % by volume of kerosene. The fuel also contains polycyclic aromatic hydrocarbons (PAH), but in very small volumes compared to the major components. The physical and chemical properties of each component (or block) of the hydrocarbon mixture influence its migration rate and fate. Some components of the fuel will volatilize, some are soluble in water but the vast majority are non-soluble. Although the solubility of these so called Light Nonaqueous Phase Liquids (LNAPL) in water is small they are highly toxic. We need to consider transport of the soluble components of the LNAPL in the melt-water, and transport of the non-soluble components with the melt-water system. Transport and storage can occur through and in snow (or firn), crevasses, and cavities on, in or under the glacier. Storage in, and contamination of, basal sediments, located below the glacier, or pro-glacial sediments, in front of the glacier are also

  1. Proton Transport

    Science.gov (United States)

    Pohorille, Andrew; DeVincenzi, Donald L. (Technical Monitor)

    2001-01-01

    The transport of protons across membranes is an essential process for both bioenergetics of modern cells and the origins of cellular life. All living systems make use of proton gradients across cell walls to convert environmental energy into a high-energy chemical compound, adenosine triphosphate (ATP), synthesized from adenosine diphosphate. ATP, in turn, is used as a source of energy to drive many cellular reactions. The ubiquity of this process in biology suggests that even the earliest cellular systems were relying on proton gradient for harvesting environmental energy needed to support their survival and growth. In contemporary cells, proton transfer is assisted by large, complex proteins embedded in membranes. The issue addressed in this Study was: how the same process can be accomplished with the aid of similar but much simpler molecules that could have existed in the protobiological milieu? The model system used in the study contained a bilayer membrane made of phospholipid, dimyristoylphosphatidylcholine (DMPC) which is a good model of the biological membranes forming cellular boundaries. Both sides of the bilayer were surrounded by water which simulated the environment inside and outside the cell. Embedded in the membrane was a fragment of the Influenza-A M$_2$ protein and enough sodium counterions to maintain system neutrality. This protein has been shown to exhibit remarkably high rates of proton transport and, therefore, is an excellent model to study the formation of proton gradients across membranes. The Influenza M$_2$ protein is 97 amino acids in length, but a fragment 25 amino acids long. which contains a transmembrane domain of 19 amino acids flanked by three amino acids on each side. is sufficient to transport protons. Four identical protein fragments, each folded into a helix, aggregate to form small channels spanning the membrane. Protons are conducted through a narrow pore in the middle of the channel in response to applied voltage. This

  2. Formation, fate and leaching of chloroform in coniferous forest soils

    Energy Technology Data Exchange (ETDEWEB)

    Albers, Christian N., E-mail: calbers@ruc.dk [Dept. Geochemistry, Geological Survey of Denmark and Greenland, O. Voldgade 10, DK-1350, Copenhagen (Denmark); Laier, Troels; Jacobsen, Ole S. [Dept. Geochemistry, Geological Survey of Denmark and Greenland, O. Voldgade 10, DK-1350, Copenhagen (Denmark)

    2010-10-15

    Research highlights: {yields} Chloroform may be formed in coniferous forest soil. {yields} The formed chloroform may enter the groundwater in {mu}g/L concentrations. {yields} Clear seasonal patterns in chloroform formation in soil are observed. {yields} Sorption and degradation affects the fate of chloroform in forest soil. - Abstract: Chloroform is a common groundwater pollutant but also a natural compound in forest ecosystems. Leaching of natural chloroform from forest soil to groundwater was followed by regular analysis of soil air and groundwater from multilevel wells at four different sites in Denmark for a period of up to 4 a. Significant seasonal variation in chloroform was observed in soil air 0.5 m below surface ranging at one site from 120 ppb by volume in summer to 20 ppb during winter. With depth, the seasonal variation diminished gradually, ranging from 30 ppb in summer to 20 ppb during winter, near the groundwater table. Chloroform in the shallowest groundwater ranged from 0.5-1.5 {mu}g L{sup -1} at one site to 2-5 {mu}g L{sup -1} at another site showing no clear correlation with season. Comparing changes in chloroform in soil air versus depth with on-site recorded meteorological data indicated that a clear relationship appears between rain events and leaching of chloroform. Chloroform in top soil air co-varied with CO{sub 2} given a delay of 3-4 weeks providing evidence for its biological origin. This was confirmed during laboratory incubation experiments which further located the fermentation layer as the most chloroform producing soil horizon. Sorption of chloroform to soils, examined using {sup 14}C-CHCl{sub 3}, correlated with organic matter content, being high in the upper organic rich soils and low in the deeper more minerogenic soils. The marked decrease in chloroform in soil with depth may in part be due to microbial degradation which was shown to occur at all depths by laboratory tests using {sup 14}C-CHCl{sub 3}.

  3. Fate of Manuscripts Rejected From the Red Journal

    International Nuclear Information System (INIS)

    Purpose: To evaluate characteristics associated with higher rates of acceptance for original manuscripts submitted for publication to the International Journal of Radiation Oncology • Biology • Physics (IJROBP) and describe the fate of rejected manuscripts. Methods and Materials: Manuscripts submitted to the IJROBP from May 1, 2010, to August 31, 2010, and May 1, 2012, to August 31, 2012, were evaluated for author demographics and acceptance status. A PubMed search was performed for each IJROBP-rejected manuscript to ascertain whether the manuscript was ultimately published elsewhere. The Impact Factor of the accepting journal and the number of citations of the published manuscript were also collected. Results: Of the 500 included manuscripts, 172 (34.4%) were accepted and 328 (65.6%) were rejected. There was no significant difference in acceptance rates according to gender or degree of the submitting author, but there were significant differences seen based on the submitting author's country, rank, and h-index. On multivariate analysis, earlier year submitted (P<.0001) and higher author h-index (P=.006) remained significantly associated with acceptance into the IJROBP. Two hundred thirty-five IJROBP-rejected manuscripts (71.7%) were ultimately published in a PubMed-listed journal as of July 2014. There were no significant differences in any submitting author characteristics. Journals accepting IJROBP-rejected manuscripts had a lower median [interquartile range] 2013 impact factor compared with the IJROBP (2.45 [1.53-3.71] vs 4.176). The IJROBP-rejected manuscripts ultimately published elsewhere had a lower median [interquartile range] number of citations (1 [0-4] vs 6 [2-11]; P<.001), which persisted on multivariate analysis. Conclusions: The acceptance rate for manuscripts submitted to the IJROBP is approximately one-third, and approximately 70% of rejected manuscripts are ultimately published in other PubMed-listed journals, but these ultimate

  4. Fate of Manuscripts Rejected From the Red Journal

    Energy Technology Data Exchange (ETDEWEB)

    Holliday, Emma B., E-mail: emmaholliday@gmail.com [Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Yang, George [The University of South Florida Morsani College of Medicine, Tampa, Florida (United States); Jagsi, Reshma [Department of Radiation Oncology, The University of Michigan, Ann Arbor, Michigan (United States); Hoffman, Karen E. [Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Bennett, Katherine Egan; Grace, Calley [Scientific Publications, American Society for Radiation Oncology, Fairfax, Virginia (United States); Zietman, Anthony L. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States)

    2015-01-01

    Purpose: To evaluate characteristics associated with higher rates of acceptance for original manuscripts submitted for publication to the International Journal of Radiation Oncology • Biology • Physics (IJROBP) and describe the fate of rejected manuscripts. Methods and Materials: Manuscripts submitted to the IJROBP from May 1, 2010, to August 31, 2010, and May 1, 2012, to August 31, 2012, were evaluated for author demographics and acceptance status. A PubMed search was performed for each IJROBP-rejected manuscript to ascertain whether the manuscript was ultimately published elsewhere. The Impact Factor of the accepting journal and the number of citations of the published manuscript were also collected. Results: Of the 500 included manuscripts, 172 (34.4%) were accepted and 328 (65.6%) were rejected. There was no significant difference in acceptance rates according to gender or degree of the submitting author, but there were significant differences seen based on the submitting author's country, rank, and h-index. On multivariate analysis, earlier year submitted (P<.0001) and higher author h-index (P=.006) remained significantly associated with acceptance into the IJROBP. Two hundred thirty-five IJROBP-rejected manuscripts (71.7%) were ultimately published in a PubMed-listed journal as of July 2014. There were no significant differences in any submitting author characteristics. Journals accepting IJROBP-rejected manuscripts had a lower median [interquartile range] 2013 impact factor compared with the IJROBP (2.45 [1.53-3.71] vs 4.176). The IJROBP-rejected manuscripts ultimately published elsewhere had a lower median