WorldWideScience

Sample records for environmental fate modelling

  1. Environmental fate of rice paddy pesticides in a model ecosystem.

    Science.gov (United States)

    Tomizawa, C; Kazano, H

    1979-01-01

    The distribution and metabolic fate of several rice paddy pesticides were evaluated in a modified model ecosystem. Among the three BHC isomers, beta-isomer was the most stable and bioconcentrated in all of the organisms. Alpha- and gamma-isomers were moderately persistent and degraded to some extent during the 33 day period. Disulfoton was relatively persistent due to the transformation to its oxidation products. Pyridaphenthion was fairly biodegradable. N-Phenyl maleic hydrazide derived from the hydrolysis of pyridaphenthion was not detected in the organisms though it was found in the aquarium water after 33 days. Cartap and edifenphos were considerably biodegradable, and the ratio of the conversion to water soluble metabolites was very high. There was a distinct difference in the persistence of Kitazin P and edifenphos in the aquarium water. It appeared that the hydrolysis rate of the pesticides affected their fate in the organisms. PCP appeared to be moderately biodegradable. CNP was considerably stable and stored in the organisms though the concentration in the aquarium water was relatively low. The persistence and distribution of the pesticides in the model ecosystem were dependent on their chemical structures. In spite of the limitation derived from short experimental period, the model ecosystem may be applicable for predicting the environmental fate of pesticides.

  2. OPERA models for predicting physicochemical properties and environmental fate endpoints.

    Science.gov (United States)

    Mansouri, Kamel; Grulke, Chris M; Judson, Richard S; Williams, Antony J

    2018-03-08

    The collection of chemical structure information and associated experimental data for quantitative structure-activity/property relationship (QSAR/QSPR) modeling is facilitated by an increasing number of public databases containing large amounts of useful data. However, the performance of QSAR models highly depends on the quality of the data and modeling methodology used. This study aims to develop robust QSAR/QSPR models for chemical properties of environmental interest that can be used for regulatory purposes. This study primarily uses data from the publicly available PHYSPROP database consisting of a set of 13 common physicochemical and environmental fate properties. These datasets have undergone extensive curation using an automated workflow to select only high-quality data, and the chemical structures were standardized prior to calculation of the molecular descriptors. The modeling procedure was developed based on the five Organization for Economic Cooperation and Development (OECD) principles for QSAR models. A weighted k-nearest neighbor approach was adopted using a minimum number of required descriptors calculated using PaDEL, an open-source software. The genetic algorithms selected only the most pertinent and mechanistically interpretable descriptors (2-15, with an average of 11 descriptors). The sizes of the modeled datasets varied from 150 chemicals for biodegradability half-life to 14,050 chemicals for logP, with an average of 3222 chemicals across all endpoints. The optimal models were built on randomly selected training sets (75%) and validated using fivefold cross-validation (CV) and test sets (25%). The CV Q 2 of the models varied from 0.72 to 0.95, with an average of 0.86 and an R 2 test value from 0.71 to 0.96, with an average of 0.82. Modeling and performance details are described in QSAR model reporting format and were validated by the European Commission's Joint Research Center to be OECD compliant. All models are freely available as an open

  3. Addressing the complexity of water chemistry in environmental fate modeling for engineered nanoparticles.

    Science.gov (United States)

    Sani-Kast, Nicole; Scheringer, Martin; Slomberg, Danielle; Labille, Jérôme; Praetorius, Antonia; Ollivier, Patrick; Hungerbühler, Konrad

    2015-12-01

    Engineered nanoparticle (ENP) fate models developed to date - aimed at predicting ENP concentration in the aqueous environment - have limited applicability because they employ constant environmental conditions along the modeled system or a highly specific environmental representation; both approaches do not show the effects of spatial and/or temporal variability. To address this conceptual gap, we developed a novel modeling strategy that: 1) incorporates spatial variability in environmental conditions in an existing ENP fate model; and 2) analyzes the effect of a wide range of randomly sampled environmental conditions (representing variations in water chemistry). This approach was employed to investigate the transport of nano-TiO2 in the Lower Rhône River (France) under numerous sets of environmental conditions. The predicted spatial concentration profiles of nano-TiO2 were then grouped according to their similarity by using cluster analysis. The analysis resulted in a small number of clusters representing groups of spatial concentration profiles. All clusters show nano-TiO2 accumulation in the sediment layer, supporting results from previous studies. Analysis of the characteristic features of each cluster demonstrated a strong association between the water conditions in regions close to the ENP emission source and the cluster membership of the corresponding spatial concentration profiles. In particular, water compositions favoring heteroaggregation between the ENPs and suspended particulate matter resulted in clusters of low variability. These conditions are, therefore, reliable predictors of the eventual fate of the modeled ENPs. The conclusions from this study are also valid for ENP fate in other large river systems. Our results, therefore, shift the focus of future modeling and experimental research of ENP environmental fate to the water characteristic in regions near the expected ENP emission sources. Under conditions favoring heteroaggregation in these

  4. Illustrating sensitivity in environmental fate models using partitioning maps - application to selected contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, T.; Wania, F. [Univ. of Toronto at Scarborough - DPES, Toronto (Canada)

    2004-09-15

    Generic environmental multimedia fate models are important tools in the assessment of the impact of organic pollutants. Because of limited possibilities to evaluate generic models by comparison with measured data and the increasing regulatory use of such models, uncertainties of model input and output are of considerable concern. This led to a demand for sensitivity and uncertainty analyses for the outputs of environmental fate models. Usually, variations of model predictions of the environmental fate of organic contaminants are analyzed for only one or at most a few selected chemicals, even though parameter sensitivity and contribution to uncertainty are widely different for different chemicals. We recently presented a graphical method that allows for the comprehensive investigation of model sensitivity and uncertainty for all neutral organic chemicals simultaneously. This is achieved by defining a two-dimensional hypothetical ''chemical space'' as a function of the equilibrium partition coefficients between air, water, and octanol (K{sub OW}, K{sub AW}, K{sub OA}), and plotting sensitivity and/or uncertainty of a specific model result to each input parameter as function of this chemical space. Here we show how such sensitivity maps can be used to quickly identify the variables with the highest influence on the environmental fate of selected, chlorobenzenes, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), hexachlorocyclohexanes (HCHs) and brominated flame retardents (BFRs).

  5. Environmental fate and transport analysis with compartment modeling

    National Research Council Canada - National Science Library

    Little, Keith W

    2012-01-01

    .... Discussing various modeling issues in a single volume, this text provides an introduction to a specific numerical modeling technique called the compartment approach and offers a practical user's guide to the GEM...

  6. Evaluating the Environmental Fate of Short-Chain Chlorinated Paraffins (SCCPs) in the Nordic Environment Using a Dynamic Multimedia Model

    OpenAIRE

    Krogseth, Ingjerd Sunde; Breivik, Knut; Arnot, Jon A; Wania, Frank; Borgen, Anders; Schlabach, Martin

    2013-01-01

    Short chain chlorinated paraffins (SCCPs) raise concerns due to their potential for persistence, bioaccumulation, long-range transport and adverse effects. An understanding of their environmental fate remains limited, partly due to the complexity of the mixture. The purpose of this study was to evaluate whether a mechanistic, integrated, dynamic environmental fate and bioaccumulation multimedia model (CoZMoMAN) can reconcile what is known about environmental emissions and human exposure of SC...

  7. Environmental fate and exposure models: advances and challenges in 21st century chemical risk assessment.

    Science.gov (United States)

    Di Guardo, Antonio; Gouin, Todd; MacLeod, Matthew; Scheringer, Martin

    2018-01-24

    Environmental fate and exposure models are a powerful means to integrate information on chemicals, their partitioning and degradation behaviour, the environmental scenario and the emissions in order to compile a picture of chemical distribution and fluxes in the multimedia environment. A 1995 pioneering book, resulting from a series of workshops among model developers and users, reported the main advantages and identified needs for research in the field of multimedia fate models. Considerable efforts were devoted to their improvement in the past 25 years and many aspects were refined; notably the inclusion of nanomaterials among the modelled substances, the development of models at different spatial and temporal scales, the estimation of chemical properties and emission data, the incorporation of additional environmental media and processes, the integration of sensitivity and uncertainty analysis in the simulations. However, some challenging issues remain and require research efforts and attention: the need of methods to estimate partition coefficients for polar and ionizable chemical in the environment, a better description of bioavailability in different environments as well as the requirement of injecting more ecological realism in exposure predictions to account for the diversity of ecosystem structures and functions in risk assessment. Finally, to transfer new scientific developments into the realm of regulatory risk assessment, we propose the formation of expert groups that compare, discuss and recommend model modifications and updates and help develop practical tools for risk assessment.

  8. Assessment of the Environmental Fate of the Herbicides Flufenacet and Metazachlor with the SWAT Model.

    Science.gov (United States)

    Fohrer, Nicola; Dietrich, Antje; Kolychalow, Olga; Ulrich, Uta

    2014-01-01

    This study aims to assess the environmental fate of the commonly used herbicides flufenacet and metazachlor in the Northern German Lowlands with the ecohydrological Soil and Water Assessment Tool (SWAT model) and to test the sensitivity of pesticide-related input parameters on the modeled transport dynamics. The river discharge of the Kielstau watershed was calibrated (Nash-Sutcliffe efficiency [NSE], 0.83; = 0.84) and validated (NSE, 0.76; = 0.77) for a daily time step. The environmental fate of metazachlor (NSE, 0.68; = 0.62) and flufenacet (NSE, 0.13; = 0.51) was simulated adequately. In comparison to metazachlor, the simulated flufenacet concentration and loads show a lower model efficiency due to the weaker simulation of the stream flow. The in-stream herbicide loads were less than 0.01% of the applied amount in the observed time period and thus not in conflict with European Environmental Legislation. The sensitivity analysis showed that, besides the accurate simulation of stream flow, the parameterization of the temporal and spatial distribution of the herbicide application throughout the watershed is the key factor for appropriate modeling results, whereas the physicochemical properties of the pesticides play a minor role in the modeling process. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  9. Environmental fate and transport of chemical signatures from buried landmines -- Screening model formulation and initial simulations

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-06-01

    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, estimate the subsurface total concentration, and show the phase specific concentrations at the ground surface. 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.

  10. Model ecosystem determination of the metabolic and environmental fate of tetrachloro-DDT

    International Nuclear Information System (INIS)

    Cole, R.B.; Metcalf, R.L.

    1987-01-01

    A potential hazardous waste site investigation was conducted by the Environmental Protection Agency to determine whether ground water, surface water, or area soils and sediments were contaminated as a result of waster water discharges or improper solid waste disposal practices of a pesticide manufacturer. One of the compounds discharged into the environment was 1,1,1,2-tetrachloro-2,2-bis(p-chlorophenyl)ethane, commonly referred to as tetrachloro-DDT. Unlike a great many of the DDT analogs, tetrachloro-DDT has come under only limited scrutiny, mainly because it was dismissed as having poor insecticidal properties relative to DDT and other analogs. Its metabolism in ingesting organisms, and degradative pathways in the environment have consequently been left uncertain. This model ecosystem study was undertaken to examine the unanswered questions concerning the metabolic and environmental fate of tetrachloro-DDT. The relevance of this study pertains to disposal practices of pesticide manufacturers who use tetrachloro-DDT as a product precursor

  11. 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)

    Guangguo, Ying [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; Xiangyang, Yu [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.

  12. 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)

    Ying Guangguo; Yu Xiangyang; Kookana, Rai S.

    2007-01-01

    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

  13. Evaluating the environmental fate of short-chain chlorinated paraffins (SCCPs) in the Nordic environment using a dynamic multimedia model.

    Science.gov (United States)

    Krogseth, Ingjerd S; Breivik, Knut; Arnot, Jon A; Wania, Frank; Borgen, Anders R; Schlabach, Martin

    2013-12-01

    Short chain chlorinated paraffins (SCCPs) raise concerns due to their potential for persistence, bioaccumulation, long-range transport and adverse effects. An understanding of their environmental fate remains limited, partly due to the complexity of the mixture. The purpose of this study was to evaluate whether a mechanistic, integrated, dynamic environmental fate and bioaccumulation multimedia model (CoZMoMAN) can reconcile what is known about environmental emissions and human exposure of SCCPs in the Nordic environment. Realistic SCCP emission scenarios, resolved by formula group, were estimated and used to predict the composition and concentrations of SCCPs in the environment and the human food chain. Emissions at the upper end of the estimated range resulted in predicted total concentrations that were often within a factor of 6 of observations. Similar model performance for a complex group of organic contaminants as for the well-known polychlorinated biphenyls strengthens the confidence in the CoZMoMAN model and implies a relatively good mechanistic understanding of the environmental fate of SCCPs. However, the degree of chlorination predicted for SCCPs in sediments, fish, and humans was higher than observed and poorly established environmental half-lives and biotransformation rate constants contributed to the uncertainties in the predicted composition and ∑SCCP concentrations. Improving prediction of the SCCP composition will also require better constrained estimates of the composition of SCCP emissions. There is, however, also large uncertainty and lack of coherence in the existing observations, and better model-measurement agreement will require improved analytical methods and more strategic sampling. More measurements of SCCP levels and compositions in samples from background regions are particularly important.

  14. Exposure levels, environmental fate modelling and human health risk assessment of lindane in Ghana

    International Nuclear Information System (INIS)

    Adu-Kumi, S.

    2011-01-01

    -HCH which is a known environmental estrogen, was predominant contaminant measured (geometric mean concentrations 4.18 ng g -1 lipid wt. and 4.35 ng g -1 lipid wt. for pooled and individual samples respectively). The levels of Lindane, α-HCH and β-HCH in edible fish (catfish and tilapia) sourced from Lake Bosumtwi and the Weija Lake, were concurrently investigated using HRGC/HRMS. Concentrations of HCHs were found to be generally low (mainly limits of detection) probably reflecting the historical use of Lindane and technical HCH mixtures. Catfish sourced from Lake Volta (purchased from the Madina market) however contained appreciable amounts of Lindane (average concentration of 0.72 ng g -1 lipid wt). Measured values are lower than the maximum acceptable limit for human consumption established by the FAO/WHO (FAO/WHO, 1986). Hence there is no potential health risk from HCHs (Lindane, α-HCH and β-HCH) in fish for the general population of Ghana. Level III and level IV fugacity models were successfully applied to investigate the environmental fate of Lindane in the compartments of air, water, sediment, soil and biota (fish). Model estimates showed that air, water, soil and fish constitute important exposure pathways of Lindane for the general population of Ghana. The estimated total amount of Lindane accumulated in all media at steady-state was 136 tonnes, the soil compartment accounting for ore than 97% of the total accumulation. Time trends in concentration and fluxes simulated in for the period 1959-2020 predicted that less than 1% of the 2002 concentration levels of Lindane in air, water and soil, respectively, will be left in 2020. Finally, health risks associated with the exposure of the general population of Ghana to Lindane via the pathways of air, water, soil, food (or diet) were characterized using the combined field measurements and results of the multi-media environmental fate modelling. Diet (mainly vegetables), soil and to a lesser extent water constituted

  15. Choice of pesticide fate models

    International Nuclear Information System (INIS)

    Balderacchi, Matteo; Trevisan, Marco; Vischetti, Costantino

    2006-01-01

    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 [it

  16. Predictions by the multimedia environmental fate model SimpleBox compared to field data: Intermedia concentration ratios of two phthalate esters

    NARCIS (Netherlands)

    Struijs J; Peijnenburg WJGM; ECO

    2003-01-01

    The multimedia environmental fate model SimpleBox is applied to compute steady-state concentration ratios with the aim to harmonize environmetal quality objectives of air, water, sediment and soil. In 1995 the Dutch Health Council recommended validation of the model. Several activities were

  17. Evaluating the environmental fate of pharmaceuticals using a level III model based on poly-parameter linear free energy relationships

    International Nuclear Information System (INIS)

    Zukowska, Barbara; Breivik, Knut; Wania, Frank

    2006-01-01

    We recently proposed how to expand the applicability of multimedia models towards polar organic chemicals by expressing environmental phase partitioning with the help of poly-parameter linear free energy relationships (PP-LFERs). Here we elaborate on this approach by applying it to three pharmaceutical substances. A PP-LFER-based version of a Level III fugacity model calculates overall persistence, concentrations and intermedia fluxes of polar and non-polar organic chemicals between air, water, soil and sediments at steady-state. Illustrative modeling results for the pharmaceuticals within a defined coastal region are presented and discussed. The model results are highly sensitive to the degradation rate in water and the equilibrium partitioning between organic carbon and water, suggesting that an accurate description of this particular partitioning equilibrium is essential in order to obtain reliable predictions of environmental fate. The PP-LFER based modeling approach furthermore illustrates that the greatest mobility in aqueous phases may be experienced by pharmaceuticals that combines a small molecular size with strong H-acceptor properties

  18. Evaluating the environmental fate of pharmaceuticals using a level III model based on poly-parameter linear free energy relationships

    Energy Technology Data Exchange (ETDEWEB)

    Zukowska, Barbara [Department of Analytical Chemistry, Chemical Faculty, Gdansk University of Technology, 11/12 G. Narutowicza St., 80-952 Gdansk (Poland); Breivik, Knut [NILU- Norwegian Institute for Air Research, P.O. Box 100, NO-2027 Kjeller (Norway)]. E-mail: knut.breivik@nilu.no; Wania, Frank [Department of Physical and Environmental Sciences, University of Toronto at Scarborough, 1265 Military Trail, Scarborough, Ontario, M1C 1A4 (Canada)

    2006-04-15

    We recently proposed how to expand the applicability of multimedia models towards polar organic chemicals by expressing environmental phase partitioning with the help of poly-parameter linear free energy relationships (PP-LFERs). Here we elaborate on this approach by applying it to three pharmaceutical substances. A PP-LFER-based version of a Level III fugacity model calculates overall persistence, concentrations and intermedia fluxes of polar and non-polar organic chemicals between air, water, soil and sediments at steady-state. Illustrative modeling results for the pharmaceuticals within a defined coastal region are presented and discussed. The model results are highly sensitive to the degradation rate in water and the equilibrium partitioning between organic carbon and water, suggesting that an accurate description of this particular partitioning equilibrium is essential in order to obtain reliable predictions of environmental fate. The PP-LFER based modeling approach furthermore illustrates that the greatest mobility in aqueous phases may be experienced by pharmaceuticals that combines a small molecular size with strong H-acceptor properties.

  19. Environmental fate model for ultra-low-volume insecticide applications used for adult mosquito management

    Science.gov (United States)

    Schleier, Jerome J.; Peterson, Robert K.D.; Irvine, Kathryn M.; Marshall, Lucy M.; Weaver, David K.; Preftakes, Collin J.

    2012-01-01

    One of the more effective ways of managing high densities of adult mosquitoes that vector human and animal pathogens is ultra-low-volume (ULV) aerosol applications of insecticides. The U.S. Environmental Protection Agency uses models that are not validated for ULV insecticide applications and exposure assumptions to perform their human and ecological risk assessments. Currently, there is no validated model that can accurately predict deposition of insecticides applied using ULV technology for adult mosquito management. In addition, little is known about the deposition and drift of small droplets like those used under conditions encountered during ULV applications. The objective of this study was to perform field studies to measure environmental concentrations of insecticides and to develop a validated model to predict the deposition of ULV insecticides. The final regression model was selected by minimizing the Bayesian Information Criterion and its prediction performance was evaluated using k-fold cross validation. Density of the formulation and the density and CMD interaction coefficients were the largest in the model. The results showed that as density of the formulation decreases, deposition increases. The interaction of density and CMD showed that higher density formulations and larger droplets resulted in greater deposition. These results are supported by the aerosol physics literature. A k-fold cross validation demonstrated that the mean square error of the selected regression model is not biased, and the mean square error and mean square prediction error indicated good predictive ability.

  20. The environmental fate of polybrominated diphenyl ethers in the centre of Stockholm - Assessment using a multimedia fugacity model

    Energy Technology Data Exchange (ETDEWEB)

    Palm, Anna

    2001-01-01

    A local-scale assessment of the environmental fate of three congeners of polybrominated diphenyl ethers (PBDEs) has been performed for the centre of Stockholm. The partitioning properties and main transport processes of these congeners in Stockholm are identified using a site-specific multimedia fugacity model, called CeStoc, that was developed and parameterized for the area of interest. CeStoc was based on level III and IV fugacity models. Five compartments were included: air, water, soil, sediment and an organic film covering the impervious surfaces in the city. The model was satisfactory calibrated with the PAH fluoranthene, before it was run for the compounds of interest. Validation with environmental levels of PBDEs was made where possible, showing reasonable agreement with model results. According to the CeStoc results, the majority of the PBDEs emitted are transported out of the region through air advection, implying that Stockholm may act as a source for chemical release to other regions. The largest sink for PBDEs in Stockholm is soil, closely followed by sediment, the two compartments together accounting for about 98 % of the total amount remaining in the system. The degree of bromination does not seem to have a large impact on the environmental distribution in this area, but further research on e.g. physical-chemical properties is necessary before this can be finally concluded. Predicted concentrations of individual PBDE congeners in sediment and water lie in the same range as measured levels of individual PCB-congeners, indicating that PBDEs could have an environmental impact of about the same size as the PCBs.

  1. Environmental fate of pesticides applied on coffee crops in ...

    African Journals Online (AJOL)

    The aim of this paper was evaluate the environmental fate of pesticides applied in coffee crops in southeast of Brazil, using the level I fugacity model. Chemical and physical characteristics of the pesticides were considered in different environmental compartments and applied fugacity equations. The preliminary evaluation ...

  2. Development and application of the microbial fate and transport module for the Agricultural Policy/Environmental eXtender (APEX) model

    Science.gov (United States)

    Hong, E.; Park, Y.; Muirhead, R.; Jeong, J.; Pachepsky, Y. A.

    2017-12-01

    Pathogenic microorganisms in recreational and irrigation waters remain the subject of concern. Water quality models are used to estimate microbial quality of water sources, to evaluate microbial contamination-related risks, to guide the microbial water quality monitoring, and to evaluate the effect of agricultural management on the microbial water quality. The Agricultural Policy/Environmental eXtender (APEX) is the watershed-scale water quality model that includes highly detailed representation of agricultural management. The APEX currently does not have microbial fate and transport simulation capabilities. The objective of this work was to develop the first APEX microbial fate and transport module that could use the APEX conceptual model of manure removal together with recently introduced conceptualizations of the in-stream microbial fate and transport. The module utilizes manure erosion rates found in the APEX. Bacteria survival in soil-manure mixing layer was simulated with the two-stage survival model. Individual survival patterns were simulated for each manure application date. Simulated in-stream microbial fate and transport processes included the reach-scale passive release of bacteria with resuspended bottom sediment during high flow events, the transport of bacteria from bottom sediment due to the hyporheic exchange during low flow periods, the deposition with settling sediment, and the two-stage survival. Default parameter values were available from recently published databases. The APEX model with the newly developed microbial fate and transport module was applied to simulate seven years of monitoring data for the Toenepi watershed in New Zealand. Based on calibration and testing results, the APEX with the microbe module reproduced well the monitored pattern of E. coli concentrations at the watershed outlet. The APEX with the microbial fate and transport module will be utilized for predicting microbial quality of water under various agricultural

  3. Modeling Engineered Nanomaterials (ENMs) Fate and Transport in Aquatic Ecosystems

    Science.gov (United States)

    Under the Toxic Substances Control Act (TSCA), the Environmental Protection Agency (EPA) is required to perform new chemical reviews of engineered nanomaterials (ENMs) identified in pre-manufacture notices. However, environmental fate models developed for traditional contaminants...

  4. Development and evaluation of the bacterial fate and transport module for the Agricultural Policy/Environmental eXtender (APEX) model.

    Science.gov (United States)

    Hong, Eun-Mi; Park, Yongeun; Muirhead, Richard; Jeong, Jaehak; Pachepsky, Yakov A

    2018-02-15

    The Agricultural Policy/Environmental eXtender (APEX) is a watershed-scale water quality model that includes detailed representation of agricultural management. The objective of this work was to develop a process-based model for simulating the fate and transport of manure-borne bacteria on land and in streams with the APEX model. The bacteria model utilizes manure erosion rates to estimate the amount of edge-of-field bacteria export. Bacteria survival in manure is simulated as a two-stage process separately for each manure application event. In-stream microbial fate and transport processes include bacteria release from streambeds due to sediment resuspension during high flow events, active release from the streambed sediment during low flow periods, bacteria settling with sediment, and survival. Default parameter values were selected from published databases and evaluated based on field observations. The APEX model with the newly developed microbial fate and transport module was applied to simulate fate and transport of the fecal indicator bacterium Escherichia coli in the Toenepi watershed, New Zealand that was monitored for seven years. The stream network of the watershed ran through grazing lands with daily bovine waste deposition. Results show that the APEX with the bacteria module reproduced well the monitored pattern of E. coli concentrations at the watershed outlet. The APEX with the microbial fate and transport module will be utilized for predicting microbial quality of water as affected by various agricultural practices, evaluating monitoring protocols, and supporting the selection of management practices based on regulations that rely on fecal indicator bacteria concentrations. Published by Elsevier B.V.

  5. Development and evaluation of the microbial fate and transport module for the Agricultural Policy/Environmental eXtender (APEX) model

    Science.gov (United States)

    Hong, Eun-Mi; Park, Yongeun; Muirhead, Richard; Pachepsky, Yakov

    2017-04-01

    Pathogenic microorganisms in recreational and irrigation waters remain the subject of concern. Water quality models are used to estimate microbial quality of water sources, to evaluate microbial contamination-related risks, to guide the microbial water quality monitoring, and to evaluate the effect of agricultural management on the microbial water quality. The Agricultural Policy/Environmental eXtender (APEX) is the watershed-scale water quality model that includes highly detailed representation of agricultural management. The APEX currently does not have microbial fate and transport simulation capabilities. The objective of this work was to develop the first APEX microbial fate and transport module that could use the APEX conceptual model of manure removal together with recently introduced conceptualizations of the in-stream microbial fate and transport. The module utilizes manure erosion rates found in the APEX. The total number of removed bacteria was set to the concentrations of bacteria in soil-manure mixing layer and eroded manure amount. Bacteria survival in soil-manure mixing layer was simulated with the two-stage survival model. Individual survival patterns were simulated for each manure application date. Simulated in-stream microbial fate and transport processes included the reach-scale passive release of bacteria with resuspended bottom sediment during high flow events, the transport of bacteria from bottom sediment due to the hyporheic exchange during low flow periods, the deposition with settling sediment, and the two-stage survival. Default parameter values were available from recently published databases. The APEX model with the newly developed microbial fate and transport module was applied to simulate seven years of monitoring data for the Toenepi watershed in New Zealand. The stream network of the watershed ran through grazing lands with the daily bovine waste deposition. Based on calibration and testing results, the APEX with the microbe module

  6. 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...

  7. A multimedia fate model to evaluate the fate of PAHs in Songhua River, China

    International Nuclear Information System (INIS)

    Wang Ce; Feng Yujie; Sun Qingfang; Zhao Shanshan; Gao Peng; Li Bailian

    2012-01-01

    A multimedia fate model coupling dynamic water flow with a level IV fugacity model has been developed and applied to simulate the temporal and spatial fate of Polycyclic Aromatic Hydrocarbons (PAHs) in the Songhua River, China. The model has two components: in the first, the one-dimensional network kinematic wave equation is used to calculate varying water flow and depth. In the second, Fugacity IV equations are implemented to predict contaminant distributions in four environmental media. The estimated concentrations of eight PAHs in Songhua River are obtained, and all simulated results are in acceptable agreement with monitoring data, as verified with the Theil’s inequality coefficient test. The sensitivity of PAH concentration in each environmental phase to input parameters are also evaluated. Our results show the model predicts reasonably accurate contaminant concentrations in natural rivers, and that it can be used to supply necessary information for control and management of water pollution. - Highlights: ► The model used was developed based on kinematic wave equation and level IV fugacity principle. ► The model was applied to describe the fate and transport of organic chemicals in natural river. ► The concentrations of PAHs in water column were satisfactorily simulated when compared with monitoring data. ► Temporal and spatial variability of PAHs concentration among multimedia environmental phases was illustrated. - A dynamic water flow based multimedia fate model is developed to characterize the fate and transport of organic contaminant in natural rivers.

  8. Modeling Engineered Nanomaterials (ENMs) Fate and ...

    Science.gov (United States)

    Under the Toxic Substances Control Act (TSCA), the Environmental Protection Agency (EPA) is required to perform new chemical reviews of engineered nanomaterials (ENMs) identified in pre-manufacture notices. However, environmental fate models developed for traditional contaminants are limited in their ability to simulate the environmental behavior of nanomaterials due to incomplete understanding and representation of the processes governing nanomaterial distribution in the environment and by scarce empirical data quantifying the interaction of nanomaterials with environmental surfaces. We have updated the Water Quality Analysis Simulation Program (WASP), version S, to incorporate nanomaterials as an explicitly simulated state variable. WASPS now has the capability to simulate nanomaterial fate and transport in surface waters and sediments using heteroaggregation, the kinetic process governing the attachment of nanomaterials to particles and subsequently ENM distribution in the aqueous and sediment phases. Unlike dissolved chemicals which use equilibrium partition coefficients, heteroaggregation consists of a particle collision rate and an attachment efficiency ( lXhet) that generally acts as a one direction process. To demonstrate, we used a derived a het value from sediment attachment studies to parameterize WASP for simulation of multi walled carbon nanotube (MWCNT) transport in Brier Creek, a coastal plain river located in central eastern Georgia, USA and a tr

  9. Environmental fate of tungsten from military use

    International Nuclear Information System (INIS)

    Clausen, Jay L.; Korte, Nic

    2009-01-01

    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

  10. 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.

  11. Modelling the fate of organic micropollutants in stormwater ponds

    DEFF Research Database (Denmark)

    Vezzaro, Luca; Eriksson, Eva; Ledin, Anna

    2011-01-01

    ). The four simulated organic stormwater MP (iodopropynyl butylcarbamate — IPBC, benzene, glyphosate and pyrene) were selected according to their different urban sources and environmental fate. This ensures that the results can be extended to other relevant stormwater pollutants. All three models use......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 assessment and a dynamic multimedia fate model (Stormwater Treatment Unit Model for Micro Pollutants — STUMP...

  12. 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....

  13. 40 CFR 158.1300 - Environmental fate data requirements table.

    Science.gov (United States)

    2010-07-01

    ... transformation products. 7. Environmental chemistry methods used to generate data associated with this study must... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Environmental fate data requirements table. 158.1300 Section 158.1300 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED...

  14. Fate modelling of chemical compounds with incomplete data sets

    DEFF Research Database (Denmark)

    Birkved, Morten; Heijungs, Reinout

    2011-01-01

    Impact assessment of chemical compounds in Life Cycle Impact Assessment (LCIA) and Environmental Risk Assessment (ERA) requires a vast amount of data on the properties of the chemical compounds being assessed. These data are used in multi-media fate and exposure models, to calculate risk levels...... in an approximate way. The idea is that not all data needed in a multi-media fate and exposure model are completely independent and equally important, but that there are physical-chemical and biological relationships between sets of chemical properties. A statistical model is constructed to underpin this assumption...... and other indicators. ERA typically addresses one specific chemical, but in an LCIA, the number of chemicals encountered may be quite high, up to hundreds or thousands. This study explores the development of meta-models, which are supposed to reflect the “true”multi-media fate and exposure model...

  15. Assessing the environmental fate of selected polybrominated diphenyl ethers in the region surrounding the Zhuoshui River of Taiwan based on an Equilibrium Constant fugacity model

    Science.gov (United States)

    O'Driscoll, Kieran; Doherty, Rory; Robinson, Jill; Chiang, Wen-Son; Kao Kao, Ruey-Chy

    2015-04-01

    Polybrominated diphenyl ethers (PBDEs) are a group of flame retardants that have been in use since the 1970s. They are included in the list of hazardous substances known as persistent organic pollutants (POPs) because they are extremely hazardous to the environment and human health. PBDEs have been extensively used in industry and manufacturing in Taiwan, thus its citizens are at high risk of exposure to these chemicals. An assessment of the environmental fate of these compounds in the Zhuoshui river and Changhua County regions of western Taiwan, and also including the adjacent area of the Taiwan Strait, was conducted for three high risk congeners, BDE-47, -99 and -209, to obtain information regarding the partitioning, advection, transfer and long range transport potential of the PBDEs in order to identify the level of risk posed by the pollutants in this region. The results indicate that large amounts of PBDEs presently reside in all model compartments - air, soil, water, and sediment - with particularly high levels found in air and especially in sediment. The high levels found in sediment, particularly for BDE-209, are significant, since there is the threat of these pollutants entering the food chain, either directly through benthic feeding, or through resuspension and subsequent feeding in the pelagic region of the water column which is a distinct possibility in the strong currents found within the Taiwan Strait. Another important result is that a substantial portion of emissions leave the model domain directly through advection, particularly for BDE-47 (58%) and BDE-209 (75%), thus posing a risk to adjacent communities. Model results were generally in reasonable agreement with available measured concentrations. In air, model concentrations are in reasonably good agreement with available measured values. For both BDE-47 and -99, model concentrations are a factor of 2-3 higher and BDE-209 within the range of measured values. In soil, model results are somewhat

  16. The environmental release and fate of antibiotics.

    Science.gov (United States)

    Manzetti, Sergio; Ghisi, Rossella

    2014-02-15

    Antibiotics have been used as medical remedies for over 50 years and have recently emerged as new pollutants in the environment. This review encompasses the fate of several antibiotics in the environment, including sulfonamides, nitrofurans, terfenadines, cephalosporins and cyclosporins. It investigates the cycle of transfer from humans and animals including their metabolic transformation. The results show that antibiotic metabolites are of considerable persistence and are localized to ground-water and drinking water supplies. Furthermore, the results also show that several phases of the cycle of antibiotics in the environment are not well understood, such as how low concentrations of antibiotic metabolites in the diet affect humans and animals. This review also shows that improved wastewater decontamination processes are remediating factors for these emerging pollutants. The results obtained here may help legislators and authorities in understanding the fate and transformation of antibiotics in the environment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Degradation of Fluorotelomer-Based Polymers Contributes to the Global Occurrence of Fluorotelomer Alcohol and Perfluoroalkyl Carboxylates: A Combined Dynamic Substance Flow and Environmental Fate Modeling Analysis.

    Science.gov (United States)

    Li, Li; Liu, Jianguo; Hu, Jianxin; Wania, Frank

    2017-04-18

    Using coupled dynamic substance flow and environmental fate models, CiP-CAFE and BETR-Global, we investigated whether the degradation of side-chain fluorotelomer-based polymers (FTPs), mostly in waste stocks (i.e., landfills and dumps), serves as a long-term source of fluorotelomer alcohols (FTOHs) and perfluoroalkyl carboxylates (PFCAs) to the global environment. The modeling results indicate that, in the wake of the worldwide transition from long-chain to short-chain products, in-use stocks of C8 FTPs will peak and decline afterward, while the in-use stocks of C6 FTPs, and the waste stocks of both FTPs will generally grow. FTP degradation in waste stocks is making an increasing contribution to FTOH generation, the bulk of which readily migrates from waste stocks and degrades into PFCAs in the environment; the remaining part of the generated FTOHs degrade in waste stocks, which makes those stocks reservoirs that slowly release PFCAs into the environment over the long run because of the low leaching rate and extreme persistence of PFCAs. Short-chain FTPs have higher relative release rates of PFCAs from waste stocks than long-chain ones. Estimates of in-use and waste stocks of FTPs were more sensitive to the selected lifespan of finished products, while those of the emissions of FTOHs and PFCAs were more sensitive to the degradation half-life of FTPs in waste stocks. Our preliminary calculations highlight the need for environmentally sound management of obsolete FTP-containing products into the foreseeable future.

  18. Environmental fate and ecotoxicological risk of the antibiotic sulfamethoxazole across the Katari catchment (Bolivian Altiplano) : application of the GREAT-ER model

    OpenAIRE

    Archundia, D.; Boithias, Laurie; Duwig, Céline; Morel, M. C.; Aviles, G. F.; Martins, J. M. F.

    2018-01-01

    Antibiotics are emergent contaminants that can induce adverse effects in terrestrial and aquatic organisms. The surface water compartment is of particular concern as it receives direct waste water discharge. Modeling is highlighted as an essential tool to understand the fate and behavior of these compounds and to assess their eco-toxicological risk. This study aims at testing the ability of the GREAT-ER model in simulating sulfamethoxazole (SMX) concentrations in the surface waters of the ari...

  19. Do environmental dynamics matter in fate models? Exploring scenario dynamics for a terrestrial and an aquatic system.

    Science.gov (United States)

    Morselli, Melissa; Terzaghi, Elisa; Di Guardo, Antonio

    2018-01-24

    Nowadays, there is growing interest in inserting more ecological realism into risk assessment of chemicals. On the exposure evaluation side, this can be done by studying the complexity of exposure in the ecosystem, niche partitioning, e.g. variation of the exposure scenario. Current regulatory predictive approaches, to ensure simplicity and predictive ability, generally keep the scenario as static as possible. This could lead to under or overprediction of chemical exposure depending on the chemical and scenario simulated. To account for more realistic exposure conditions, varying temporally and spatially, additional scenario complexity should be included in currently used models to improve their predictive ability. This study presents two case studies (a terrestrial and an aquatic one) in which some polychlorinated biphenyls (PCBs) were simulated with the SoilPlusVeg and ChimERA models to show the importance of scenario variation in time (biotic and abiotic compartments). The results outlined the importance of accounting for planetary boundary layer variation and vegetation dynamics to accurately predict air concentration changes and the timing of chemical dispersion from the source in terrestrial systems. For the aquatic exercise, the results indicated the need to account for organic carbon forms (particulate and dissolved organic carbon) and vegetation biomass dynamics. In both cases the range of variation was up to two orders of magnitude depending on the congener and scenario, reinforcing the need for incorporating such knowledge into exposure assessment.

  20. Modeling the Environmental Fate of Graphene Oxide and Its Phototransformation Products in Brier Creek Watershed Using the Water Quality Analysis Simulation Program 8 (WASP8)

    Science.gov (United States)

    Han, Y.; Bouchard, D.; Chang, X.; Hsieh, H. S.; Knightes, C. D.; Spear, J.; Zepp, R. G.

    2017-12-01

    The production of graphene-family nanoparticles (GFNs) appreciably increased in recent years. Among GFNs, graphene oxide (GO) is one of the most highly studied members due to its inexpensive synthesis cost compared to graphene, its stability in aqueous media and its broad application. However, GO also has been found to be the most toxic among GFNs. Lab studies showed that GO undergoes phototransformation in surface waters, resulting in products that include reduced GO (rGO) and polycyclic aromatic hydrocarbons (PAHs). Due to technical and analytical limitations, it is still difficult to conduct in-situ measurement of GO and rGO concentrations released in the environment, and it is of utmost importance to establish a model that can predict their environmental exposure concentrations in the environment. In this study, we develop a fate and transport model to predict time-dependent environmental exposure concentrations of GO for the Brier Creek Watershed in the GA coastal plain. We investigate the influence of sunlight radiation on the distribution of GO and its phototransformation products in the watershed over a 20-year period using the most updated Water Quality Analysis Simulation Program (WASP8). Flow rate, sediment transport data and sunlight radiation data are input into WASP8, and WASP8 is used to internally calculate a GO phototransformation rate and productions of rGO and PAHs. Heteroaggregation coefficients of GO and rGO with suspended solids were measured in an EPA laboratory, and then input into WASP8. GO and rGO concentrations in the watershed are calculated by WASP8. Mass fraction results show that GO is the predominant species among GO derived species, which account for 99% of the mass throughout the whole watershed of interest, while rGO species, including free rGO and rGO heteroaggregated to suspended solids, only account for 1%. We also found that almost all free GO and rGO are present in water column due to their extremely low settling velocity. r

  1. 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...

  2. Human population intake fractions and environmental fate factors of toxic pollutants in life cycle impact assessment

    NARCIS (Netherlands)

    Huijbregts, M.A.J.; Struijs, Jaap; Goedkoop, Mark; Heijungs, Reinout; Jan Hendriks, A.; Van De Meent, Dik

    2005-01-01

    The present paper outlines an update of the fate and exposure part of the fate, exposure and effects model USES-LCA. The new fate and exposure module of USES-LCA was applied to calculate human population intake fractions and fate factors of the freshwater, marine and terrestrial environment for 3393

  3. Fate and transport of fragrance materials in principal environmental sinks.

    Science.gov (United States)

    Zhang, Xiaolei; Brar, Satinder Kaur; Yan, Song; Tyagi, Rajeshwar Dayal; Surampalli, Rao Y

    2013-10-01

    Fragrance materials are widely present in the environment, such as air, water, and soil. Concerns have been raised due to the increasing utilization and suspected impact on human health. The bioaccumulating property is considered as one of the causes of the toxicity to human beings. The removal of fragrance materials from environmental sinks has not been paid enough attention due to the lack of regulation and research on their toxicity. This paper provides systematic information on how fragrance materials are transferred to the environment, how do they affect human lives, and what is their fate in water, wastewater, wastewater sludge, and soil. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Regulatory relevant and reliable methods and data for determining the environmental fate of manufactured nanomaterials

    DEFF Research Database (Denmark)

    Baun, Anders; Sayre, Phil; Steinhäuser, Klaus Günter

    2017-01-01

    The widespread use of manufactured nanomaterials (MN) increases the need for describing and predicting their environmental fate and behaviour. A number of recent reviews have addressed the scientific challenges in disclosing the governing processes for the environmental fate and behaviour of MNs,...... data. Gaps do however exist in test methods for environmental fate, such as methods to estimate heteroagglomeration and the tendency for MNs to transform in the environment.......The widespread use of manufactured nanomaterials (MN) increases the need for describing and predicting their environmental fate and behaviour. A number of recent reviews have addressed the scientific challenges in disclosing the governing processes for the environmental fate and behaviour of MNs......, however there has been less focus on the regulatory adequacy of the data available for MN. The aim of this paper is therefore to review data, testing protocols and guidance papers which describe the environmental fate and behaviour of MN with a focus on their regulatory reliability and relevance. Given...

  5. Fate of triazoles in softwood upon environmental exposure.

    Science.gov (United States)

    Kukowski, Klara; Martinská, Veronika; Sedgeman, Carl A; Kuplic, Paige; Kozliak, Evguenii I; Fisher, Stephen; Kubátová, Alena

    2017-10-01

    Determining the fate of preservatives in commercial wood products is essential to minimize their losses and improve protective impregnation techniques. The fate of triazole fungicides in ponderosa pine wood was investigated in both outdoor and controlled-environment experiments using a representative triazole, tebuconazole (TAZ), which was accompanied by propiconazole (PAZ) in selected experiments. The study was designed to mimic industrial settings used in window frame manufacturing. To investigate the TAZ fate in detail, loosely and strongly bound fractions were differentiated using a multi-step extraction. The loosely bound TAZ fraction extracted through two sonications accounted for 85± 5% of the total TAZ, while the strongly bound TAZ was extracted only with an exhaustive Soxhlet extraction and corresponded to the remaining 15± 5%. A significant fraction (∼80%) of the original TAZ remained in the wood despite a six-month exposure to harsh environmental conditions, maintaining wood preservation and assuring minimal environmental impact. Depletion of loosely bound TAZ was observed from cross-sectional surfaces when exposed to rain, high humidity and sunlight. Water leaching was deemed to be the major route leading to triazole losses from wood. Leaching rate was found to be slightly higher for TAZ than for PAZ. The contribution of bio-, photo- and thermal degradation of triazoles was negligible as both PAZ and TAZ sorbed in wood remained intact. Triazole evaporation was also found to be minor at the moderate temperature (20-25 °C) recorded throughout the outdoor study. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Development and evaluation of the microbial fate and transport module for the Agricultural Policy/Environmental eXtender (APEX) model

    Science.gov (United States)

    Microbial contamination of waters in agricultural watershed is the critical public health issue. The watershed-scale model has been proven to be one of the candidate tools for predicting microbial water quality and evaluating management practices. The Agricultural Policy/Environmental eXtender (APEX...

  7. Modeling the fate and transport of bacteria in agricultural and pasture lands using APEX

    Science.gov (United States)

    The Agricultural Policy/Environmental eXtender (APEX) model is a whole farm to small watershed scale continuous simulation model developed for evaluating various land management strategies. The current version, APEX0806, does not have the modeling capacity for fecal indicator bacteria fate and trans...

  8. Controls on the Environmental Fate of Compounds Controlled by Coupled Hydrologic and Reactive Processes

    Science.gov (United States)

    Hixson, J.; Ward, A. S.; McConville, M.; Remucal, C.

    2017-12-01

    Current understanding of how compounds interact with hydrologic processes or reactive processes have been well established. However, the environmental fate for compounds that interact with hydrologic AND reactive processes is not well known, yet critical in evaluating environmental risk. Evaluations of risk are often simplified to homogenize processes in space and time and to assess processes independently of one another. However, we know spatial heterogeneity and time-variable reactivities complicate predictions of environmental transport and fate, and is further complicated by the interaction of these processes, limiting our ability to accurately predict risk. Compounds that interact with both systems, such as photolytic compounds, require that both components are fully understood in order to predict transport and fate. Release of photolytic compounds occurs through both unintentional releases and intentional loadings. Evaluating risks associated with unintentional releases and implementing best management practices for intentional releases requires an in-depth understanding of the sensitivity of photolytic compounds to external controls. Lampricides, such as 3-trifluoromethyl-4-nitrophenol (TFM), are broadly applied in the Great Lakes system to control the population of invasive sea lamprey. Over-dosing can yield fish kills and other detrimental impacts. Still, planning accounts for time of passage and dilution, but not the interaction of the physical and chemical systems (i.e., storage in the hyporheic zone and time-variable decay rates). In this study, we model a series of TFM applications to test the efficacy of dosing as a function of system characteristics. Overall, our results demonstrate the complexity associated with photo-sensitive compounds through stream-hyporheic systems, and highlight the need to better understand how physical and chemical systems interact to control transport and fate in the environment.

  9. GLOBOX : A spatially differentiated global fate, intake and effect model for toxicity assessment in LCA

    NARCIS (Netherlands)

    Wegener Sleeswijk, Anneke; Heijungs, Reinout

    GLOBOX is a model for the calculation of spatially differentiated LCA toxicity characterisation factors on a global scale. It can also be used for human and environmental risk assessment. The GLOBOX model contains equations for the calculation of fate, intake and effect factors, and equations for

  10. Environmental fate of natural radioactive contaminants in fertilizers and phosphogypsum

    International Nuclear Information System (INIS)

    Batalha, Marcia Salamoni; Genuchten, Martinus Theodorus van

    2010-01-01

    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 ( 238 U and 234 U) and phosphogypsum as an amendment ( 226 Ra and 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)

  11. 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)

  12. 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

  13. Environmental fate of TCDD and Agent Orange and bioavailability to troops in Vietnam

    Energy Technology Data Exchange (ETDEWEB)

    Karch, N.J.; Watkins, D.K.; Ginevan, M.E. [Exponent, Inc., Washington, DC (United States); Young, A.L. [Oklahoma Univ., Norman, OK (United States)

    2004-09-15

    This paper reviews the environmental fate of Agent Orange and the contaminant, 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD), and discusses how this affects the bioavailability of TCDD for ground troops in Vietnam.

  14. Review of nitrogen fate models applicable to forest landscapes in the Southern U.S.

    Science.gov (United States)

    D. M. Amatya; C. G. Rossi; A. Saleh; Z. Dai; M. A. Youssef; R. G. Williams; D. D. Bosch; G. M. Chescheir; G. Sun; R. W. Skaggs; C. C. Trettin; E. D. Vance; J. E. Nettles; S. Tian

    2013-01-01

    Assessing the environmental impacts of fertilizer nitrogen (N) used to increase productivity in managed forests is complex due to a wide range of abiotic and biotic factors affecting its forms and movement. Models developed to predict fertilizer N fate (e.g., cycling processes) and water quality impacts vary widely in their design, scope, and potential application. We...

  15. 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.…

  16. Predicting the environmental fate properties of petroleum hydrocarbon mixtures

    International Nuclear Information System (INIS)

    Pisigan, R.A. Jr.; Tucker, W.A.

    1995-01-01

    The environmental fate and transport of petroleum products for risk assessment can be evaluated based on the physico-chemical properties of an indicator chemical or a surrogate compound, or the whole mixture. A study was conducted to develop a simple representation of the hydrocarbon mixture as if it contained only few constituents, each of which represents a large number of compounds. The products considered are gasoline, diesel fuel, and jet fuel (JP4). Each petroleum hydrocarbon was characterized as a mixture of six constituents: short chain alkanes, long chain alkanes, short chain cycloalkanes and alkenes, long chain cycloalkanes and alkenes, BTEX, and other aromatics. The carbon number used as a cut-off between short and long chain alkanes, alkenes, and cycloalkanes varies with the type of product. Each mixture has different average molecular weight, water solubility, vapor pressure, organic carbon partition coefficient, and air diffusivity. The properties of each constituent of gasoline were derived from the weighted average of all compounds belonging to each constituent group. For diesel fuel and JP4, the properties of each constituent were generated from the properties of the component most representative of the group. Any property that is missing or not available from common literature sources was derived from regression equations developed from the data base for gasoline. These regression equations express the property as function of the number of carbon atoms. The R 2 values of the regression equations range from 0.82--0.92. Some case studies involving petroleum product contamination in which the estimated properties were applied are presented

  17. Modelling the fate of persistent organic pollutants in Europe: parameterisation of a gridded distribution model

    International Nuclear Information System (INIS)

    Prevedouros, Konstantinos; MacLeod, Matthew; Jones, Kevin C.; Sweetman, Andrew J.

    2004-01-01

    A regionally segmented multimedia fate model for the European continent is described together with an illustrative steady-state case study examining the fate of γ-HCH (lindane) based on 1998 emission data. The study builds on the regionally segmented BETR North America model structure and describes the regional segmentation and parameterisation for Europe. The European continent is described by a 5 deg. x 5 deg. grid, leading to 50 regions together with four perimetric boxes representing regions buffering the European environment. Each zone comprises seven compartments including; upper and lower atmosphere, soil, vegetation, fresh water and sediment and coastal water. Inter-regions flows of air and water are described, exploiting information originating from GIS databases and other georeferenced data. The model is primarily designed to describe the fate of Persistent Organic Pollutants (POPs) within the European environment by examining chemical partitioning and degradation in each region, and inter-region transport either under steady-state conditions or fully dynamically. A test case scenario is presented which examines the fate of estimated spatially resolved atmospheric emissions of lindane throughout Europe within the lower atmosphere and surface soil compartments. In accordance with the predominant wind direction in Europe, the model predicts high concentrations close to the major sources as well as towards Central and Northeast regions. Elevated soil concentrations in Scandinavian soils provide further evidence of the potential of increased scavenging by forests and subsequent accumulation by organic-rich terrestrial surfaces. Initial model predictions have revealed a factor of 5-10 underestimation of lindane concentrations in the atmosphere. This is explained by an underestimation of source strength and/or an underestimation of European background levels. The model presented can further be used to predict deposition fluxes and chemical inventories, and it

  18. Environmental Behavior and Fate of Explosives in Groundwater from the Milan Army Ammunition Plant in Aquatic and Wetland Plants. Fate of TNT and RDX

    National Research Council Canada - National Science Library

    Best, Elly

    1998-01-01

    The present study was performed to elucidate the environmental behavior and fate of TNT and RDX in aquatic and wetland plants collected from a field-scale wetland demonstration deployed at Milan Army...

  19. 40 CFR 158.2150 - Microbial pesticides nontarget organisms and environmental fate data requirements table.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Microbial pesticides nontarget... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR PESTICIDES Microbial Pesticides § 158.2150 Microbial pesticides nontarget organisms and environmental fate data...

  20. Environmental fate and effects of nicotine released during cigarette production.

    Science.gov (United States)

    Seckar, Joel A; Stavanja, Mari S; Harp, Paul R; Yi, Yongsheng; Garner, Charles D; Doi, Jon

    2008-07-01

    A variety of test methods were used to study the gradation, bioaccumulation, and toxicity of nicotine. Studies included determination of the octanol-water partition coefficient, conversion to CO2 in soil and activated sludge, and evaluation of the effects on microbiological and algal inhibition as well as plant germination and root elongation. The partitioning of nicotine between octanol and water indicated that nicotine will not bioaccumulate regardless of the pH of the medium. The aqueous and soil-based biodegradation studies indicated that nicotine is readily biodegradable in both types of media. The microbiological inhibition and aquatic and terrestrial toxicity tests indicated that nicotine has low toxicity. The U.S. Environmental Protection Agency Persistence, Bioaccumulation, and Toxicity Profiler model, based on the structure of nicotine and the predictive rates of hydroxyl radical and ozone reactions, estimated an atmospheric half-life of less than 5.0 h. Using this value in the Canadian Environmental Modeling Center level III model, the half-life of nicotine was estimated as 3.0 d in water and 0.5 d in soil. This model also estimated nicotine discharge into the environment; nicotine would be expected to be found predominantly in water (93%), followed by soil (4%), air (3%), and sediment (0.4%). Using the estimated nicotine concentrations in water, soil, and sediment and the proper median effective concentrations derived from the algal growth, biomass inhibition, and buttercrunch lettuce (Lactuca sativa) seed germination and root elongation studies, hazard quotients of between 10(-7) and 10(-8) were calculated, providing further support for the conclusion that the potential for nicotine toxicity to aquatic and terrestrial species in the environment is extremely low.

  1. Environmental Application, Fate, Effects, and Concerns of Ionic Liquids: A Review.

    Science.gov (United States)

    Amde, Meseret; Liu, Jing-Fu; Pang, Long

    2015-11-03

    Ionic liquids (ILs) comprise mostly of organic salts with negligible vapor pressure and low flammability that are proposed as replacements for volatile solvents. ILs have been promoted as "green" solvents and widely investigated for their various applications. Although the utility of these chemicals is unquestionable, their toxic effects have attracted great attention. In order to manage their potential hazards and design environmentally benign ILs, understanding their environmental behavior, fate and effects is important. In this review, environmentally relevant issues of ILs, including their environmental application, environmental behavior and toxicity are addressed. In addition, also presented are the influence of ILs on the environmental fate and toxicity of other coexisting contaminants, important routes for designing nontoxic ILs and the techniques that might be adopted for the removal of ILs.

  2. Environmental Fate and Analysis of Ptaquiloside from the Bracken Fern

    DEFF Research Database (Denmark)

    Clauson-Kaas, Frederik

    The naturally occurring phytotoxin ptaquiloside (PTA) has long been known to be both acute toxic and carcinogenic. Contents of more than 1% ptaquiloside on dry weight has been detected in bracken (Pteridium spp.), a fern distributed across the globe in often dense populations. This work focused...... on the fate of PTA in the soil-water system, from where it may leach to drinking water sources. PTA was detected in concentrations up to 2.2 µg/L in natural waters receiving drainage from bracken populations, and was found in both surface and groundwater. It was shown that ptaquiloside leached off bracken...... fronds (the leaves of ferns) in concentrations up to 169 µ/L during rainfall events. Rainfall further determined the concentration in a stream that drained a bracken-covered catchment, suggesting that this is a potent driver of ptaquiloside exposure in the environment. In both pure and natural waters, p...

  3. Surface Immobilization of Engineered Nanomaterials for in Situ Study of their Environmental Transformations and Fate

    Science.gov (United States)

    The transformation and environmental fate of engineered nanomaterials (ENMs) is the focus of intense research due to concerns about their potential impacts in the environment as a result of their uniquely engineered properties. Many approaches are being applied to investigate th...

  4. Environmental fate of hexabromocyclododecane from a new Canadian electronic recycling facility.

    Science.gov (United States)

    Tomko, Geoffrey; McDonald, Karen M

    2013-01-15

    An electronics recycling facility began operation at the municipal landfill site for the City of Edmonton, Canada in March 2008 with the goal of processing 30,000 tonnes of electronic wastes per year. Of the many by-products from the process, brominated fire retardants such as hexabromocyclododecane (HBCD) can evolve off of e-wastes and be released into the environmental media. HBCD has been identified by many countries and international bodies as a chemical of concern because of its ability to bioaccumulate in the ecosystem. An evaluation of the potential emission of HBCD indicates that up to 500 kg per year may be released from a landfill and recycling facility such as that operating in Edmonton. A multimedia fugacity model was used to evaluate the dispersion and fate of atmospherically emitted HBCD traveling into surrounding agricultural land and forested parkland. The model indicates that the three isomers of HBCD partitioned into environmental media similarly. Much of the HBCD is lost through atmospheric advection, but it is also found in soil and sediment. Modeled air concentrations are similar to those measured at locations with a history of e-waste recycling. Since HBCD has been shown to bioaccumulate, the HBCD released from this source has the long-term potential to affect agricultural food crops and the park ecosystem. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Developing climatic scenarios for pesticide fate modelling in Europe

    International Nuclear Information System (INIS)

    Blenkinsop, S.; Fowler, H.J.; Dubus, I.G.; Nolan, B.T.; Hollis, J.M.

    2008-01-01

    A climatic classification for Europe suitable for pesticide fate modelling was constructed using a 3-stage process involving the identification of key climatic variables, the extraction of the dominant modes of spatial variability in those variables and the use of k-means clustering to identify regions with similar climates. The procedure identified 16 coherent zones that reflect the variability of climate across Europe whilst maintaining a manageable number of zones for subsequent modelling studies. An analysis of basic climatic parameters for each zone demonstrates the success of the scheme in identifying distinct climatic regions. Objective criteria were used to identify one representative 26-year daily meteorological series from a European dataset for each zone. The representativeness of each series was then verified against the zonal classifications. These new FOOTPRINT climate zones provide a state-of-the-art objective classification of European climate complete with representative daily data that are suitable for use in pesticide fate modelling. - The FOOTPRINT climatic zones provide an objective climatic classification and daily climate series that may be used for the modelling of pesticide fate across Europe

  6. A fate model for nitrogen dynamics in the Scheldt basin

    Science.gov (United States)

    Haest, Pieter Jan; van der Kwast, Johannes; Broekx, Steven; Seuntjens, Piet

    2010-05-01

    The European Union (EU) adopted the Water Framework Directive (WFD) in 2000 ensuring that all aquatic ecosystems meet ‘good ecological status' by 2015. However, the large population density in combination with agricultural and industrial activities in some European river basins pose challenges for river basin managers in meeting this status. The EU financed AQUAREHAB project (FP7) specifically examines the ecological and economic impact of innovative rehabilitation technologies for multi-pressured degraded waters. For this purpose, a numerical spatio-temporal model is developed to evaluate innovative technologies versus conventional measures at the river basin scale. The numerical model describes the nitrogen dynamics in the Scheldt river basin. Nitrogen is examined since nitrate is of specific concern in Belgium, the country comprising the largest area of the Scheldt basin. The Scheldt basin encompasses 20000 km2 and houses over 10 million people. The governing factors describing nitrogen fluxes at this large scale differ from the field scale with a larger uncertainty on input data. As such, the environmental modeling language PCRaster was selected since it was found to provide a balance between process descriptions and necessary input data. The resulting GIS-based model simulates the nitrogen dynamics in the Scheldt basin with a yearly time step and a spatial resolution of 1 square kilometer. A smaller time step is being evaluated depending on the description of the hydrology. The model discerns 4 compartments in the Scheldt basin: the soil, shallow groundwater, deep groundwater and the river network. Runoff and water flow occurs along the steepest slope in all model compartments. Diffuse emissions and direct inputs are calculated from administrative and statistical data. These emissions are geographically defined or are distributed over the domain according to land use and connectivity to the sewer system. The reactive mass transport is described using

  7. Fate and transport modelling of uranium in Port Hope Harbour

    International Nuclear Information System (INIS)

    Pinilla, C.E.; Garisto, N.; Peters, R.

    2010-01-01

    Fate and transport modelling of contaminants in Port Hope Harbour and near-shore Lake Ontario was undertaken in support of an ecological and human health risk assessment. Uranium concentrations in the Harbour and near-shore Lake Ontario due to groundwater and storm water loadings were estimated with a state-of-the-art 3D hydrodynamic and contaminant transport model (ECOMSED). The hydrodynamic model was simplified to obtain a first estimate of the flow pattern in the Harbour. The model was verified with field data using a tracer (fluoride). The modelling results generally showed good agreement with the tracer field data. (author)

  8. Climate-based archetypes for the environmental fate assessment of chemicals.

    Science.gov (United States)

    Ciuffo, Biagio; Sala, Serenella

    2013-11-15

    Emissions of chemicals have been on the rise for years, and their impacts are greatly influenced by spatial differentiation. Chemicals are usually emitted locally but their impact can be felt both locally and globally, due to their chemical properties and persistence. The variability of environmental parameters in the emission compartment may affect the chemicals' fate and the exposure at different orders of magnitude. The assessment of the environmental fate of chemicals and the inherent spatial differentiation requires the use of multimedia models at various levels of complexity (from a simple box model to complex computational and high-spatial-resolution models). The objective of these models is to support ecological and human health risk assessment, by reducing the uncertainty of chemical impact assessments. The parameterisation of spatially resolved multimedia models is usually based on scenarios of evaluative environments, or on geographical resolutions related to administrative boundaries (e.g. countries/continents) or landscape areas (e.g. watersheds, eco-regions). The choice of the most appropriate scale and scenario is important from a management perspective, as a balance should be reached between a simplified approach and computationally intensive multimedia models. In this paper, which aims to go beyond the more traditional approach based on scale/resolution (cell, country, and basin), we propose and assess climate-based archetypes for the impact assessment of chemicals released in air. We define the archetypes based on the main drivers of spatial variability, which we systematically identify by adopting global sensitivity analysis techniques. A case study that uses the high resolution multimedia model MAPPE (Multimedia Assessment of Pollutant Pathways in the Environment) is presented. Results of the analysis showed that suitable archetypes should be both climate- and chemical-specific, as different chemicals (or groups of them) have different traits

  9. Challenges in assessing the environmental fate and exposure of nano silver

    International Nuclear Information System (INIS)

    Whiteley, Cherrie M; Jones, Kevin C; Sweetman, Andy J; Dalla Valle, Matteo

    2011-01-01

    There are significant challenges in assessing the fate and exposure of nano particles (NPs) owing to the lack of information on their use and potential pathways and sinks in the environment. This paper discusses these issues using nanosilver as a case study. The approach taken is to assess the production of nanosilver, the range of products that utilise its properties, potential environmental release pathways and subsequent fate. Estimates of UK nanosilver released into the environment have been made and sewage sludge identified as an important receiving compartment. This work aims to highlight the on-going challenges faced when assessing NPs in the environment. Using nanosilver as an example, difficulties in assessing production, use and release are discussed. The study also recommends a potential approach to assess the fate and behaviour assessment of nanosilver in the environment.

  10. Sources and fate of environmental radioactivity at the earth's surface

    International Nuclear Information System (INIS)

    El-Daoushy, F.

    2010-01-01

    Sources and fate of environmental radioactivity at the earth surface This is to link environmental radioactivity to RP in Africa? To describe the benefits of Africa from this field in terms of RP, safety and security policies. To create a mission and a vision to fulfil the needs of ONE PEOPLE, ONE GOAL, ONE FAITH. Sources, processes and fate of environmental radioactivity Previous experience helps setting up an African agenda.(1) Factors influencing cosmogenic radionuclides(2) Factors influencing artificial radionuclides: (a) nuclear weapon-tests (b) nuclear accidents (c) Energy, mining and industrial waste (3) Factors influencing the global Rn-222 and its daughters. (4) Dynamics of cycles of natural radioactivity, e.g. Pb-210. (5) Environmental radiotracers act as DIAGNOSTIC TOOLS to assess air and water quality and impacts of the atmospheric and hydrospheric compartments on ecosystems.6) Definition of base-lines for rehabilitation and protection. Climate influences sources/behaviour/fate of environmental radioactivity. Impacts on life forms in Africa would be severe. Assessing environmental radioactivity resolves these issue

  11. Monitoring fate and behaviour of Nanoceria under relevant environmental conditions

    CSIR Research Space (South Africa)

    Tancu, Y

    2014-11-01

    Full Text Available ). The results revealed significant tendency of nCeO¬2 to undergo aggregation, agglomeration and certain degree of deagglomeration processes under different environmental conditions. Moreover, the findings suggested that both electrostatic and steric interactions...

  12. The environmental fate of polybrominated diphenyl ethers in the Great Lakes Basin

    Science.gov (United States)

    Gouin, Todd William

    Semi-volatile organic compounds, such as the polybrominated diphenyl ethers (PBDEs) have the potential to undergo long-range atmospheric transport (LRAT) to remote locations, which can increase the exposure of sensitive ecosystems to potentially harmful substances. Regulatory instruments, such as the Stockholm Convention on persistent organic pollutants (POPs), have been implemented to limit and/or prevent this exposure. Through the acquisition of scientific data, knowledge can be gained about the environmental fate and human exposure of chemical substances, and the risks associated with using those substances assessed. PBDEs are a class of flame retardants that are used in a wide range of commercial products. In response to growing concern over the detection of PBDEs in remote regions, a number of regulatory bodies have implemented measures to restrict the use of PBDEs. Using a suite of environmental fate models it is shown that PBDEs will most likely partition to organic carbon in soil and sediment, and that their persistence in the environment will be strongly influenced by their reactivity in those compartments. The transport potential of the PBDEs is investigated using the transport and persistence level III model TaPL3, using model environments with and without vegetation. It is suggested that the LRAT potential of the PBDEs is likely to be greater for the more volatile lower brominated congeners than for the higher brominated congeners, and that the LRAT may be sensitive to seasonal changes in the environment, such as temperature, vegetation and changes in precipitation. Furthermore, model results suggest that the PBDEs may be subject to a "spring pulse" effect, whereby concentrations are elevated in air during the early spring. Field studies support the theory of a "spring pulse" effect, where concentrations were observed to be five times greater during the period between snowmelt and bud burst than the average concentration before and after, but conclude

  13. Study of the photodegradation of a fragrance ingredient for aquatic environmental fate assessment.

    Science.gov (United States)

    Lin, Jianming; Emberger, Matthew

    2017-04-01

    Photodegradation is an important abiotic degradation process to be taken into account for more accurate assessment of the fate of chemicals in the aquatic environment, especially those that are not readily biodegradable. Although the significant role of indirect photodegradation in the environmental fate of chemicals has been revealed in recent research, because of the many confounding factors affecting its kinetics, no straightforward approaches can be used to investigate this degradation process for environmental fate assessment. The indirect photodegradation of a fragrance ingredient named Pamplewood was studied in this work for its fate assessment. Indirect photodegradation rates under various indoor and outdoor conditions were measured by using an LC-MS method. Although the half-lives varied from 4 to 13 days, they collectively indicated that Pamplewood is intrinsically photolabile and can undergo rapid photodegradation. Results from quencher experiments revealed that ⋅OH was the main reactive intermediate responsible for indirect photodegradation, with a half-life of about 18 days in sunlit surface water, based on the experimentally determined second-order rate constant (8.48 ± 0.19 × 10 9  M -1  s -1 ). Photodegradation products of Pamplewood were also studied by GC-MS, LC-MS and total organic carbon content analyses. The results indicated that intermediates of Pamplewood photodegradation continued to photodegrade into smaller and more polar species. Complete mineralization of Pamplewood was observed when it was reacted with hydroxyl radicals in an aqueous solution. This novel approach can be applied for a more realistic environmental fate assessment of other non-readily biodegradable, hydrolysis-resistant, and non-sunlight-absorbing fragrance ingredients. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Aquatic Environmental Contamination: The fate of Asejire Lake in ...

    African Journals Online (AJOL)

    titi_aladesanmi

    In Nigeria major cities face serious water pollution crises, in which lack of environmental control of ... stocks are at the upper end of the food chains and are vital food supplies to local ... massive fish kills and loss of aquatic life and habitats in.

  15. 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.

  16. Building 235-F Goldsim Fate And Transport Model

    International Nuclear Information System (INIS)

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

    2012-01-01

    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 and 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 ρCi/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 ρCi/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

  17. Simplified fate modelling in respect to ecotoxicological and human toxicological characterisation of emissions of chemical compounds

    DEFF Research Database (Denmark)

    Birkved, Morten; Heijungs, Reinout

    2011-01-01

    The impact assessment of chemical compounds in Life Cycle Impact Assessment (LCIA) and Environmental Risk Assessment (ERA) requires a vast amount of data on the properties of the chemical compounds being assessed. The purpose of the present study is to explore statistical options for reduction...... of the data demand associated with characterisation of chemical emissions in LCIA and ERA.Based on a USEtox™ characterisation factor set consisting of 3,073 data records, multi-dimensional bilinear models for emission compartment specific fate characterisation of chemical emissions were derived by application...... the independent chemical input parameters from the minimum data set, needed for characterisation in USEtox™, according to general availability, importance and relevance for fate factor prediction.Each approach (63% and 75% of the minimum data set needed for characterisation in USEtox™) yielded 66 meta...

  18. Aqueous chemistry of chlorine: chemistry, analysis, and environmental fate of reactive oxidant species

    Energy Technology Data Exchange (ETDEWEB)

    Jolley, R.L.; Carpenter, J.H.

    1982-01-01

    This report reviews (1) the chemistry of chlorine relative to its reactions in fresh, estuarine, and marine waters and the formation of reactive oxidant species; (2) the current status of chemical analysis of reactive chlorine species and chlorine-produced oxidant species relative to analysis of low concentrations (microgram-per-liter range) and determination of accuracy and precision of methods; and (3) the environmental fate of chlorine and chlorine-produced oxidant species.

  19. Environmental Fate and Effects of Organotin Biocides: A Molecular and Microbiological Assessment.

    Science.gov (United States)

    1986-12-12

    and effects of the toxic tributyltin species, an active agent in new ship antifouling coatings. -44-4eiped- vltratrace’butyltin measurement’ ehdl c d...environments. However, the environmental occurrence, fate and effects of the highly toxic tributyltin species leached from the paints was virtually unexplored...biodegradation of tributyltin species; and 4) provided novel molecular topological correlations between molecular geometry and toxicity of organotin

  20. 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

  1. Fate and potential environmental effects of methylenediphenyl diisocyanate and toluene diisocyanate released into the atmosphere.

    Science.gov (United States)

    Tury, Bernard; Pemberton, Denis; Bailey, Robert E

    2003-01-01

    Information from a variety of sources has been collected and summarized to facilitate an overview of the atmospheric fate and potential environmental effects of emissions of methylenediphenyl diisocyanate (MDI) or toluene diisocyanate (TDI) to the atmosphere. Atmospheric emissions of both MDI and TDI are low, both in terms of concentration and mass, because of their low volatility and the need for careful control over all aspects of their lifecycle from manufacture through disposal. Typical emission losses for TDI are 25 g/t of TDI used in slabstock foam production. MDI emission losses are lower, often less than 1 g/t of MDI used. Dispersion modeling predicts that concentrations at the fenceline or beyond are very low for typical releases. Laboratory studies show that TDI (and by analogy MDI) does not react with water in the gas phase at a significant rate. The primary degradation reaction of these aromatic diisocyanates in the atmosphere is expected to be oxidation by OH radicals with an estimated half-life of one day. Laboratory studies also show that this reaction is not expected to result in increased ground-level ozone accumulation.

  2. Interaction of Physical and Chemical Processes Controlling the Environmental Fate and Transport of Lampricides Through Stream-Hyporheic Systems

    Science.gov (United States)

    Hixson, J.; Ward, A. S.; Schmadel, N.; McConville, M.; Remucal, C.

    2016-12-01

    The transport and fate of contaminants of emerging concern through the environment is complicated by the heterogeneity of natural systems and the unique reaction pathways of individual compounds. Our current evaluation of risk is often simplified to controls assumed to be homogeneous in space and time. However, we know spatial heterogeneity and time-variable reaction rates complicate predictions of environmental transport and fate, and therefore risk. These complications are the result of the interactions between the physical and chemical systems and the time-variable equilibrium that exists between the two. Compounds that interact with both systems, such as photolytic compounds, require that both components are fully understood in order to predict transport and fate. Release of photolytic compounds occurs through both unintentional releases and intentional loadings. Evaluating risks associated with unintentional releases and implementing best management practices for intentional releases requires an in-depth understanding of the sensitivity of photolytic compounds to external controls. Lampricides, such as 3-trifluoromethyl-4-nitrophenol (TFM), are broadly applied in the Great Lakes system to control the population of invasive sea lamprey. Over-dosing can yield fish kills and other detrimental impacts. Still, planning accounts for time of passage and dilution, but not the interaction of the physical and chemical systems (i.e., storage in the hyporheic zone and time-variable decay rates). In this study, we model a series of TFM applications to test the efficacy of dosing as a function of system characteristics. Overall, our results demonstrate the complexity associated with photo-sensitive compounds through stream-hyporheic systems, and highlight the need to better understand how physical and chemical systems interact to control transport and fate in the environment.

  3. Making fate and exposure models for freshwater ecotoxicity in life cycle assessment suitable for organic acids and bases.

    Science.gov (United States)

    van Zelm, Rosalie; Stam, Gea; Huijbregts, Mark A J; van de Meent, Dik

    2013-01-01

    Freshwater fate and exposure factors were determined for organic acids and bases, making use of the knowledge on electrical interaction of ionizing chemicals and their sorption to particles. The fate factor represents the residence time in the environment whereas exposure factors equal the dissolved fraction of a chemical. Multimedia fate, exposure, and effect model USES-LCA was updated to take into account the influence of ionization, based upon the acid dissociation constant (pK(a)) of a chemical, and the environmental pH. Freshwater fate (FF) and exposure (XF) factors were determined for 415 acids and 496 bases emitted to freshwater, air, and soil. The relevance of taking account of the degree of ionization of chemicals was tested by determining the ratio (R) of the new vs. fate and exposure factors determined with USES-LCA suitable for neutral chemicals only. Our results show that the majority of freshwater fate and exposure factors of chemicals that are largely ionized in the environment are larger with the ionics model compared to the factors determined with the neutrals model version. R(FF) ranged from 2.4×10(-1) to 1.6×10(1) for freshwater emissions, from 1.2×10(-2) to 2.0×10(4) for soil emissions and from 5.8×10(-2) to 6.0×10(3) for air emissions, and R(XF) from 5.3×10(-1) to 2.2×10(1). Prediction of changed solid-water partitioning, implying a change in runoff and in removal via sedimentation, and prediction of negligible air-water partition coefficient, leading to negligible volatilization were the main contributors to the changes in freshwater fate factors. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Agrochemical fate models applied in agricultural areas from Colombia

    Science.gov (United States)

    Garcia-Santos, Glenda; Yang, Jing; Andreoli, Romano; Binder, Claudia

    2010-05-01

    The misuse application of pesticides in mainly agricultural catchments can lead to severe problems for humans and environment. Especially in developing countries where there is often found overuse of agrochemicals and incipient or lack of water quality monitoring at local and regional levels, models are needed for decision making and hot spots identification. However, the complexity of the water cycle contrasts strongly with the scarce data availability, limiting the number of analysis, techniques, and models available to researchers. Therefore there is a strong need for model simplification able to appropriate model complexity and still represent the processes. We have developed a new model so-called Westpa-Pest to improve water quality management of an agricultural catchment located in the highlands of Colombia. Westpa-Pest is based on the fully distributed hydrologic model Wetspa and a fate pesticide module. We have applied a multi-criteria analysis for model selection under the conditions and data availability found in the region and compared with the new developed Westpa-Pest model. Furthermore, both models were empirically calibrated and validated. The following questions were addressed i) what are the strengths and weaknesses of the models?, ii) which are the most sensitive parameters of each model?, iii) what happens with uncertainties in soil parameters?, and iv) how sensitive are the transfer coefficients?

  5. [Environmental behavior of graphene and its effect on the transport and fate of pollutants in environment].

    Science.gov (United States)

    Ren, Wen-Jie; Teng, Ying

    2014-09-01

    Graphene is one of the most popular research topics in carbon nanomaterials. Because of its special physical and chemical properties, graphene will have wide applications. As the production and application amount is increasing, graphene will be inevitably released to the environment, resulting in risks of ecological environment and human health. It is of very vital significance for evaluating environmental risks of graphene scientifically and objectively to understand its environmental behavior and fate and explore its effect on the environmental behaviors of pollutants. This paper reviewed the environmental behavior of graphene, such as colloid properties and its stability in the aqueous environment and its transport through porous media. Additionally, the paper reviewed the effect of graphene on the transport and fate of pollutants. The interactions between graphene and heavy metals or organic compounds were especially discussed. Important topics should be explored including sorption mechanisms, interactions between graphene and soil components, influence of graphene on the transport and bioavailability of pollutants in environment, as well as approaches to quantifying graphene. The review might identify potential new ideas for further research in applications of graphene.

  6. 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

  7. Using integrated environmental modeling to automate a process-based Quantitative Microbial Risk Assessment

    Science.gov (United States)

    Integrated Environmental Modeling (IEM) organizes multidisciplinary knowledge that explains and predicts environmental-system response to stressors. A Quantitative Microbial Risk Assessment (QMRA) is an approach integrating a range of disparate data (fate/transport, exposure, an...

  8. Using Integrated Environmental Modeling to Automate a Process-Based Quantitative Microbial Risk Assessment (presentation)

    Science.gov (United States)

    Integrated Environmental Modeling (IEM) organizes multidisciplinary knowledge that explains and predicts environmental-system response to stressors. A Quantitative Microbial Risk Assessment (QMRA) is an approach integrating a range of disparate data (fate/transport, exposure, and...

  9. A review of the environmental corrosion, fate and bioavailability of munitions grade depleted uranium

    Energy Technology Data Exchange (ETDEWEB)

    Handley-Sidhu, Stephanie, E-mail: s.handley-sidhu@bham.ac.uk [Water Sciences Research Group, School of Geography, Earth, Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Keith-Roach, Miranda J. [Biogeochemistry and Environmental Analytical Chemistry Research Group, and School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Lloyd, Jonathan R.; Vaughan, David J. [Williamson Research Centre for Molecular Environmental Science, and School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester M13 9PL (United Kingdom)

    2010-11-01

    Depleted uranium (DU) is a by-product of nuclear fuel enrichment and is used in antitank penetrators due to its high density, self-sharpening, and pyrophoric properties. Military activities have left a legacy of DU waste in terrestrial and marine environments, and there have been only limited attempts to clean up affected environments. Ten years ago, very little information was available on the dispersion of DU as penetrators hit their targets or the fate of DU penetrators left behind in environmental systems. However, the marked increase in research since then has improved our knowledge of the environmental impact of firing DU and the factors that control the corrosion of DU and its subsequent migration through the environment. In this paper, the literature is reviewed and consolidated to provide a detailed overview of the current understanding of the environmental behaviour of DU and to highlight areas that need further consideration.

  10. 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.

  11. Fate modeling of mercury species and fluxes estimation in an urban river

    International Nuclear Information System (INIS)

    Tong, Yindong; Zhang, Wei; Chen, Cen; Chen, Long; Wang, Wentao; Hu, Xindi; Wang, Huanhuan; Hu, Dan; Ou, Langbo; Wang, Xuejun; Wang, Qiguang

    2014-01-01

    The fate and transfer of mercury in urban river is an important environmental concern. In this study, QWASI (Quantitative Water–Air–Sediment Interaction) model was selected to estimate the levels of total mercury and three mercury species in water and sediment, and was used to quantify the fluxes of mercury at water/air and sediment/water interfaces of an urban river. The predicted mercury levels in water and sediments were closed to the measured values. Water inflow, re-suspension of sediment and diffusion from sediment to water are major input sources of mercury in water. The net mercury transfer flux from water to air was 0.16 ng/(m 2 h). At the sediment/water interface, a net total mercury transfer of 1.32 ng/(m 2 h) from water to sediment was seen. In addition to the existing dynamic flux chambers measurement, this model method could provide a new perspective to identify the distribution and transfer of mercury in the urban river. -- Highlights: • QWASI could be a good tool to quantify transfer and fate of mercury in environment. • Distribution and flux of mercury species in an urban river was modeled. • Mercury in water mainly came from water inflow, sediment re-suspension and diffusion. • Net mercury transfer from water to air and sediment were 0.16 and 1.32 ng/(m 2 h). -- Quantitative Water–Air–Sediment Interaction model was used to quantify the transfer and fate of mercury in an urban river

  12. Evaluating the usefulness of dynamic pollutant fate models for implementing the EU Water Framework Directive.

    Science.gov (United States)

    Gevaert, Veerle; Verdonck, Frederik; Benedetti, Lorenzo; De Keyser, Webbey; De Baets, Bernard

    2009-06-01

    The European Water Framework Directive (WFD) aims at achieving a good ecological and chemical status of surface waters in river basins by 2015. The chemical status is considered good if the Environmental Quality Standards (EQSs) are met for all substances listed on the priority list and eight additional specific emerging substances. To check compliance with these standards, the WFD requires the establishment of monitoring programmes. The minimum measuring frequency for priority substances is currently set at once per month. This can result in non-representative sampling and increased probability of misinterpretation of the surface water quality status. To assist in the classification of the water body, the combined use of monitoring data and pollutant fate models is recommended. More specifically, dynamic models are suggested, as possible exceedance of the quality standards can be predicted by such models. In the presented work, four realistic scenarios are designed and discussed to illustrate the usefulness of dynamic pollutant fate models for implementing the WFD. They comprise a combination of two priority substances and two rivers, representative for Western Europe.

  13. Linking the environmental loads to the fate of PPCPs in Beijing: Considering both the treated and untreated wastewater sources

    International Nuclear Information System (INIS)

    Wang, Bin; Dai, Guohua; Deng, Shubo; Huang, Jun; Wang, Yujue; Yu, Gang

    2015-01-01

    The environmental loads of pharmaceutical and personal care products (PPCPs) in Beijing were estimated from direct discharge of untreated wastewater and WWTP treated effluent. The annual environmental loads of 15 PPCP components ranged from 16.3 kg (propranolol) to 9.85 tons (caffeine). A fugacity model was developed to successfully estimate the PPCP pollution based on the estimated environmental load. The modeled results approximated the observed PPCP concentrations in Beijing. The untreated wastewater contributed significantly to PPCP pollution in Beijing, ranging from 46% (propranolol) to 99% (caffeine). The total environmental burden of target PPCPs ranged from 0.90 kg (propranolol) to 536 kg (caffeine). Water is the most important media for the fate of PPCPs. Monte Carlo-based concentration distributions of PPCPs are consistent with the observed results. The most important way to reduce the PPCP pollution is to both improve wastewater collection rate and adopt deep treatment technologies. - Highlights: • Annual environmental loads of PPCPs ranged from 16.3 kg to 9.85 tons in Beijing. • The environmental loads can be linked to PPCP pollution by fugacity model. • Untreated wastewater significantly contributed to PPCP pollution in Beijing. • The environmental burden of 15 PPCPs in Beijing ranged from 0.90 kg to 536 kg. • Uncertainty simulation successfully generated PPCP concentration distribution. - The environmental loads from both the treated and untreated wastewater sources contribute to PPCPs pollution in the surface water in Beijing, China

  14. Modeling the fate transport of cesium in crushed granite

    International Nuclear Information System (INIS)

    Lee, C.B.; Kuo, Y.M.; Hsu, C.N.; Li, M.H.; Cheng, H.P.; Teng, S.P.

    2005-01-01

    Full text of publication follows: In order to assess the safety of a underground radwaste repository, reactive transport models suitable for evaluating the fate and transport of radionuclides need to be established based on experimental observation and analysis. The goal of this study is to construct adequate models simulating the reactive transport of cesium (Cs) in crushed granite through a systematic analysis, where synthetic groundwater (SGW) and synthetic seawater (SSW) were employed as the liquid phase. To build such models, this study applied N 2 -BET, x-ray diffraction (XRD), polar-microscopy/ auto-radiography, and solid-phase digestion for the analysis of granite, kinetic batch tests for the characterization of sorption/desorption of Cs, and multi-stage advection-dispersion column tests for the determination of major transport processes and the calibration/validation of hypothesized reactive transport models. Based on the results of solid phase analysis and batch tests, a two-site Langmuir kinetic model has been determined capable of appropriately describing Cs sorption/desorption under test conditions. From the results of non-reactive HTO column tests, a mobile/immobile transport model was proposed to capture the major transport processes in our column system. However, the combination of the two-site Langmuir model and the mobile/immobile transport model failed to provide numerical breakthrough curves matching the Cs experimental breakthroughs. It implied that our model needs to be further refined. To achieve this, the setup of our column test needs to be modified first to reduce the volume of column connecting space, so that the effect of extra diffusion/dispersion on breakthroughs would be minimized and major transport characteristics can be clearly revealed. Moreover, more investigations on the reaction mechanisms and transport processes of the reactive transport system must be conducted. (authors)

  15. Modelling the fate of the Tijuana River discharge plume

    Science.gov (United States)

    van Ormondt, M.; Terrill, E.; Hibler, L. F.; van Dongeren, A. R.

    2010-12-01

    After rainfall events, the Tijuana River discharges excess runoff into the ocean in a highly turbid plume. The runoff waters contain large suspended solids concentrations, as well as high levels of toxic contaminants, bacteria, and hepatitis and enteroviruses. Public health hazards posed by the effluent often result in beach closures for several kilometers northward along the U.S. shoreline. A Delft3D model has been set up to predict the fate of the Tijuana River plume. The model takes into account the effects of tides, wind, waves, salinity, and temperature stratification. Heat exchange with the atmosphere is also included. The model consists of a relatively coarse outer domain and a high-resolution surf zone domain that are coupled with Domain Decomposition. The offshore boundary conditions are obtained from the larger NCOM SoCal model (operated by the US Navy) that spans the entire Southern California Bight. A number of discharge events are investigated, in which model results are validated against a wide range of field measurements in the San Diego Bight. These include HF Radar surface currents, REMUS tracks, drifter deployments, satellite imagery, as well as current and temperature profile measurements at a number of locations. The model is able to reproduce the observed current and temperature patterns reasonably well. Under calm conditions, the model results suggest that the hydrodynamics in the San Diego Bight are largely governed by internal waves. During rainfall events, which are typically accompanied by strong winds and high waves, wind and wave driven currents become dominant. An analysis will be made of what conditions determine the trapping and mixing of the plume inside the surfzone and/or the propagation of the plume through the breakers and onto the coastal shelf. The model is now also running in operational mode. Three day forecasts are made every 24 hours. This study was funded by the Office of Naval Research.

  16. A review of ecological effects and environmental fate of illicit drugs in aquatic ecosystems.

    Science.gov (United States)

    Rosi-Marshall, E J; Snow, D; Bartelt-Hunt, S L; Paspalof, A; Tank, J L

    2015-01-23

    Although illicit drugs are detected in surface waters throughout the world, their environmental fate and ecological effects are not well understood. Many illicit drugs and their breakdown products have been detected in surface waters and temporal and spatial variability in use translates into "hot spots and hot moments" of occurrence. Illicit drug occurrence in regions of production and use and areas with insufficient wastewater treatment are not well studied and should be targeted for further study. Evidence suggests that illicit drugs may not be persistent, as their half-lives are relatively short, but may exhibit "pseudo-persistence" wherein continual use results in persistent occurrence. We reviewed the literature on the ecological effects of these compounds on aquatic organisms and although research is limited, a wide array of aquatic organisms, including bacteria, algae, invertebrates, and fishes, have receptors that make them potentially sensitive to these compounds. In summary, illicit drugs occur in surface waters and aquatic organisms may be affected by these compounds; research is needed that focuses on concentrations of illicit drugs in areas of production and high use, environmental fate of these compounds, and effects of these compounds on aquatic ecosystems at the concentrations that typically occur in the environment. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    International Nuclear Information System (INIS)

    Sullivan, T.M.; Chehata, M.

    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. 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

    Oil and gas exploration and production at marine sites has generated concern over potential environmental impacts resulting from the discharge of spent drilling muds and cuttings. This concern has led to a broad array of publicly and privately sponsored research. This report described a cooperative modeling effort designed to focus information resulting from this research through construction of explicit equations that simulate the potential impacts of discharge drilling fluids (muds) and cuttings on marine communities. The model is the result of collaboration among more than 30 scientists. The principal cooperating organizations were the E.S. Environmental Protection Agency, the U.S. Minerals Management Service, the Offshore Operators Committee, and the Alaska Oil and Gas Association. The overall simulation model can be conceptualized as three connected submodels: Discharge and Plume Fate, Sediment Redistribution, and Benthic Community Effects. On each day of simulation, these submodels are executed in sequence, with flows of information between submodels. The Benthic Community Effects submodel can be further divided into sections that calculate mortality due to burial, mortality due to toxicity, mortality due to resuspension disturbance, and growth of the community. The model represents a series of seven discrete 1-m2 plots at specified distances along a transect in one direction away from a discharge point. It consists of coupled difference equations for which parameter values can easily be set to evaluate different conditions or to examine the sensitivity of output to various assumptions. Sets of parameter values were developed to represent four general cases or scenarios: (1) a shallow (5 m), cold environment with ice cover during a substantial fraction of the year, such as might be encountered in the Beaufort Sea, Alaska; (2) a shallow (20 m), temperate environment, such as might be encountered in the Gulf of Mexico; (3) a deeper (80 m), temperate environment

  19. An evaluation of the environmental fate and behavior of munitions materiel (Tetryl and polar metabolites of TNT) in soil and plant systems. Environmental fate and behavior of tetryl

    Energy Technology Data Exchange (ETDEWEB)

    Fellows, R.J.; Harvey, S.D.; Cataldo, D.A.

    1993-09-01

    The objective of the present studies was to elucidate the environmental behavior and fate of 2,4,6trintrophenylmethylnitramine (tetryl) in the soil/plant system in three different types of soils incubated for 60 days. No tetryl was detectable after 11 days; most of the radiolabel was associated with non-extractable soil components and four transformation products appeared rapidly, of which two were identified as N-methyl-2,4,6-trintroaniline and N-methyl-aminodinitroaniline isomer. Short-term hydroponic studies indicated no significant difference in uptake rates for the three plant species employed. Kinetic studies indicated that plants have a high affinity and capacity for absorbing tetryl. Partitioning patterns indicated that the root is the major accumulation site for tetryl. Chemical fractionation and analyses of tissues showed rapid metabolism of tetryl in tissues of all species, which proceeded toward more polar metabolic products. Plant maturity studies indicated significant differences in the total relative uptake of tetryl by all three plant species based on soil type.

  20. Modelling the Fate of Xenobiotic Trace Chemicals via Wastewater Treatment and Agricultural Resource Reuse

    DEFF Research Database (Denmark)

    Polesel, Fabio

    the comprehension of XTC fate, and thus the predictive capabilities of fate models: (i) at process scale, with a focus on sorption and biological transformation of XTCs in biological treatment systems; (ii) in full-scale WWTPs, assessing the impact of retransformation and WWTP operation on XTC elimination; and (iii......) in integrated WWTP-agricultural systems. Different modelling tools, suiting the specific purposes of our investigations, were developed, extended and/or innovatively applied. Fate models used as reference in this thesis include: the Activated Sludge Modelling framework for Xenobiotics (ASM-X); the generic WWTP...... model SimpleTreat Activity; and the dynamic soil-plant model for fate prediction in agricultural systems. Experimental and model-based observations were combined to assess sorption of ionizable XTCs onto activated sludge and XTC biotransformation in moving bed biofilm reactors (MBBRs). Most XTCs...

  1. 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.

  2. Effects of pH upon the environmental fate of [14C]fenitrothion in an aquatic microcosm

    International Nuclear Information System (INIS)

    Fisher, S.W.

    1985-01-01

    The environmental fate of [ 14 C]fenitrothion was evaluated in aquatic microcosms held at pH 8.3 or 6.7. No general effect attributable to pH was observed; however, several significant interactions were identified. Of these, the findings that statistically higher amounts of radioactivity were present in water held at pH 6.7 and that significantly less metabolism of the parent compound occurred in the organisms at pH 8.3 were preeminent. These differences seen in metabolism and environmental fate between pH values are relatively minor and do not compromise the safety of the compound

  3. Environmental Modeling Center

    Data.gov (United States)

    Federal Laboratory Consortium — The Environmental Modeling Center provides the computational tools to perform geostatistical analysis, to model ground water and atmospheric releases for comparison...

  4. Effects of nanoplastics and microplastics on toxicity, bioaccumulation, and environmental fate of phenanthrene in fresh water.

    Science.gov (United States)

    Ma, Yini; Huang, Anna; Cao, Siqi; Sun, Feifei; Wang, Lianhong; Guo, Hongyan; Ji, Rong

    2016-12-01

    Contamination of fine plastic particles (FPs), including micrometer to millimeter plastics (MPs) and nanometer plastics (NPs), in the environment has caught great concerns. FPs are strong adsorbents for hydrophobic toxic pollutants and may affect their fate and toxicity in the environment; however, such information is still rare. We studied joint toxicity of FPs with phenanthrene to Daphnia magna and effects of FPs on the environmental fate and bioaccumulation of 14 C-phenanthrene in fresh water. Within the five sizes particles we tested (from 50 nm to 10 μm), 50-nm NPs showed significant toxicity and physical damage to D. magna. The joint toxicity of 50-nm NPs and phenanthrene to D. magna showed an additive effect. During a 14-days incubation, the presence of NPs significantly enhanced bioaccumulation of phenanthrene-derived residues in daphnid body and inhibited the dissipation and transformation of phenanthrene in the medium, while 10-μm MPs did not show significant effects on the bioaccumulation, dissipation, and transformation of phenanthrene. The differences may be attributed to higher adsorption of phenanthrene on 50-nm NPs than 10-μm MPs. Our findings underlined the high potential ecological risks of FPs, and suggested that NPs should be given more concerns, in terms of their interaction with hydrophobic pollutants in the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. BETR global - A geographically-explicit global-scale multimedia contaminant fate model

    International Nuclear Information System (INIS)

    MacLeod, Matthew; Waldow, Harald von; Tay, Pascal; Armitage, James M.; Woehrnschimmel, Henry; Riley, William J.; McKone, Thomas E.; Hungerbuhler, Konrad

    2011-01-01

    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 o x 15 o grid. We demonstrate BETR Global by modeling the global sources, transport, and removal of decamethylcyclopentasiloxane (D5). - Two new software implementations of the Berkeley-Trent Global Contaminant Fate Model are available. The new model software is illustrated using a case study of the global fate of decamethylcyclopentasiloxane (D5).

  6. SIMAP oil and Orimulsion fate and effects model

    International Nuclear Information System (INIS)

    French, D.P.; Mendelsohn, D.; Rines, H.

    1995-01-01

    SIMAP, ASA's Spill Impact MAPping model system, simulates the physical fates and biological effects of spilled oils and fuels in 3-dimensional space, allow evaluation of the effectiveness of spill response activities, and evaluate probabilities of trajectories and resulting impacts. It may be used for real-time spill simulation, contingency planning, and ecological risk assessments. SIMAP has been verified for oil spills using data from the Exxon Valdez, the August 1993 No. 6 fuel spill in Tampa Bay, the North Cape No. 2 oil spill in RI January 1996, and others. SIMAP has been extended to apply to the alternative fuel Orimulsion trademark by development of algorithms describing the characteristics of this fuel and mechanisms of dispersion if it is spilled. Orimulsion is a mixture of approximately70% bitumen, surfactant, and water (about 30%). This emulsion readily mixes into the water column when it is spilled, as opposed to remaining as a surface slick as do oils. Thus, Orimulsion is tracked in the model as two fractions dispersed in an initial water volume: (1) fuel (bitumen) droplets with attached surfactant, and (2) dissolved low molecular weight aromatics. The toxicity of each component is considered separately and as additive. The model evaluates exposure, toxicity, mortality, and sublethal losses of biota resulting from the spill. Toxic effects are a function of time and temperature of exposure to concentrations, exposure to surface slicks and shoreline oil, and physiological response based on biological classifications. Losses of fish, shellfish, and wildlife are evaluated in the context of natural and harvest mortality rates in the absence of the spill

  7. 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.

  8. Multiphase CFD modeling of nearfield fate of sediment plumes

    DEFF Research Database (Denmark)

    Saremi, Sina; Hjelmager Jensen, Jacob

    2014-01-01

    Disposal of dredged material and the overflow discharge during the dredging activities is a matter of concern due to the potential risks imposed by the plumes on surrounding marine environment. This gives rise to accurately prediction of the fate of the sediment plumes released in ambient waters...

  9. Erratum: Probabilistic application of a fugacity model to predict triclosan fate during wastewater treatment.

    Science.gov (United States)

    Bock, Michael; Lyndall, Jennifer; Barber, Timothy; Fuchsman, Phyllis; Perruchon, Elyse; Capdevielle, Marie

    2010-10-01

    The fate and partitioning of the antimicrobial compound, triclosan, in wastewater treatment plants (WWTPs) is evaluated using a probabilistic fugacity model to predict the range of triclosan concentrations in effluent and secondary biosolids. The WWTP model predicts 84% to 92% triclosan removal, which is within the range of measured removal efficiencies (typically 70% to 98%). Triclosan is predominantly removed by sorption and subsequent settling of organic particulates during primary treatment and by aerobic biodegradation during secondary treatment. Median modeled removal efficiency due to sorption is 40% for all treatment phases and 31% in the primary treatment phase. Median modeled removal efficiency due to biodegradation is 48% for all treatment phases and 44% in the secondary treatment phase. Important factors contributing to variation in predicted triclosan concentrations in effluent and biosolids include influent concentrations, solids concentrations in settling tanks, and factors related to solids retention time. Measured triclosan concentrations in biosolids and non-United States (US) effluent are consistent with model predictions. However, median concentrations in US effluent are over-predicted with this model, suggesting that differences in some aspect of treatment practices not incorporated in the model (e.g., disinfection methods) may affect triclosan removal from effluent. Model applications include predicting changes in environmental loadings associated with new triclosan applications and supporting risk analyses for biosolids-amended land and effluent receiving waters. © 2010 SETAC.

  10. Probabilistic application of a fugacity model to predict triclosan fate during wastewater treatment.

    Science.gov (United States)

    Bock, Michael; Lyndall, Jennifer; Barber, Timothy; Fuchsman, Phyllis; Perruchon, Elyse; Capdevielle, Marie

    2010-07-01

    The fate and partitioning of the antimicrobial compound, triclosan, in wastewater treatment plants (WWTPs) is evaluated using a probabilistic fugacity model to predict the range of triclosan concentrations in effluent and secondary biosolids. The WWTP model predicts 84% to 92% triclosan removal, which is within the range of measured removal efficiencies (typically 70% to 98%). Triclosan is predominantly removed by sorption and subsequent settling of organic particulates during primary treatment and by aerobic biodegradation during secondary treatment. Median modeled removal efficiency due to sorption is 40% for all treatment phases and 31% in the primary treatment phase. Median modeled removal efficiency due to biodegradation is 48% for all treatment phases and 44% in the secondary treatment phase. Important factors contributing to variation in predicted triclosan concentrations in effluent and biosolids include influent concentrations, solids concentrations in settling tanks, and factors related to solids retention time. Measured triclosan concentrations in biosolids and non-United States (US) effluent are consistent with model predictions. However, median concentrations in US effluent are over-predicted with this model, suggesting that differences in some aspect of treatment practices not incorporated in the model (e.g., disinfection methods) may affect triclosan removal from effluent. Model applications include predicting changes in environmental loadings associated with new triclosan applications and supporting risk analyses for biosolids-amended land and effluent receiving waters. (c) 2010 SETAC.

  11. A polynomial based model for cell fate prediction in human diseases.

    Science.gov (United States)

    Ma, Lichun; Zheng, Jie

    2017-12-21

    Cell fate regulation directly affects tissue homeostasis and human health. Research on cell fate decision sheds light on key regulators, facilitates understanding the mechanisms, and suggests novel strategies to treat human diseases that are related to abnormal cell development. In this study, we proposed a polynomial based model to predict cell fate. This model was derived from Taylor series. As a case study, gene expression data of pancreatic cells were adopted to test and verify the model. As numerous features (genes) are available, we employed two kinds of feature selection methods, i.e. correlation based and apoptosis pathway based. Then polynomials of different degrees were used to refine the cell fate prediction function. 10-fold cross-validation was carried out to evaluate the performance of our model. In addition, we analyzed the stability of the resultant cell fate prediction model by evaluating the ranges of the parameters, as well as assessing the variances of the predicted values at randomly selected points. Results show that, within both the two considered gene selection methods, the prediction accuracies of polynomials of different degrees show little differences. Interestingly, the linear polynomial (degree 1 polynomial) is more stable than others. When comparing the linear polynomials based on the two gene selection methods, it shows that although the accuracy of the linear polynomial that uses correlation analysis outcomes is a little higher (achieves 86.62%), the one within genes of the apoptosis pathway is much more stable. Considering both the prediction accuracy and the stability of polynomial models of different degrees, the linear model is a preferred choice for cell fate prediction with gene expression data of pancreatic cells. The presented cell fate prediction model can be extended to other cells, which may be important for basic research as well as clinical study of cell development related diseases.

  12. The fate of cyanide in leach wastes at gold mines: An environmental perspective

    International Nuclear Information System (INIS)

    Johnson, Craig A.

    2015-01-01

    Highlights: • This paper reviews the fate of cyanide in mineral processing wastes at gold mines. • Ore leaching produces numerous cyanide-containing species besides the gold complex. • Many cyanide species are eliminated or sequestered naturally over time. • Sequestered cyanide can be remobilized if conditions change. • Toxicity of released solutions can be reduced by photolytic reactions or offgassing. - Abstract: This paper reviews the basic chemistry of cyanide, methods by which cyanide can be analyzed, and aspects of cyanide behavior that are most relevant to environmental considerations at mineral processing operations associated with gold mines. The emphasis is on research results reported since 1999 and on data gathered for a series of U.S. Geological Survey studies that began in the late 1990s. Cyanide is added to process solutions as the CN − anion, but ore leaching produces numerous other cyanide-containing and cyanide-related species in addition to the desired cyanocomplex of gold. These can include hydrogen cyanide (HCN); cyanometallic complexes of iron, copper, zinc, nickel, and many other metals; cyanate (CNO − ); and thiocyanate (SCN − ). The fate of these species in solid wastes and residual process solutions that remain once gold recovery activities are terminated and in any water that moves beyond the ore processing facility dictates the degree to which cyanide poses a risk to aquatic organisms and aquatic-dependent organisms in the local environment. Cyanide-containing and cyanide-related species are subject to attenuation mechanisms that lead to dispersal to the atmosphere, chemical transformation to other carbon and nitrogen species, or sequestration as cyanometallic precipitates or adsorbed species on mineral surfaces. Dispersal to the atmosphere and chemical transformation amount to permanent elimination of cyanide, whereas sequestration amounts to storage of cyanide in locations from which it can potentially be remobilized by

  13. Metals fate and transport modelling in streams and watersheds: state of the science and USEPA workshop review

    Science.gov (United States)

    Caruso, B.S.; Cox, T.J.; Runkel, Robert L.; Velleux, M.L.; Bencala, Kenneth E.; Nordstrom, D. Kirk; Julien, P.Y.; Butler, B.A.; Alpers, Charles N.; Marion, A.; Smith, Kathleen S.

    2008-01-01

    Metals pollution in surface waters from point and non-point sources (NPS) is a widespread problem in the United States and worldwide (Lofts et al., 2007; USEPA, 2007). In the western United States, metals associated with acid mine drainage (AMD) from hardrock mines in mountainous areas impact aquatic ecosystems and human health (USEPA, 1997a; Caruso and Ward, 1998; Church et al., 2007). Metals fate and transport modelling in streams and watersheds is sometimes needed for assessment and restoration of surface waters, including mining-impacted streams (Runkel and Kimball, 2002; Caruso, 2003; Velleux et al., 2006). The Water Quality Analysis Simulation Program (WASP; Wool et al., 2001), developed by the US Environmental Protection Agency (USEPA), is an example of a model used for such analyses. Other approaches exist and appropriate model selection depends on site characteristics, data availability and modelling objectives. However, there are a wide range of assumptions, input parameters, data requirements and gaps, and calibration and validation issues that must be addressed by model developers, users and decision makers. Despite substantial work on model development, their successful application has been more limited because they are not often used by decision makers for stream and watershed assessment and restoration. Bringing together scientists, model developers, users and decision makers should stimulate the development of appropriate models and improve the applicability of their results. To address these issues, the USEPA Office of Research and Development and Region 8 (Colorado, Montana, North Dakota, South Dakota, Utah and Wyoming) hosted a workshop in Denver, Colorado on February 13–14, 2007. The workshop brought together approximately 35 experts from government, academia and consulting to address the state of the art for modelling metals fate and transport, knowledge gaps and future directions in metals modelling. It focused on modelling metals in high

  14. A Review of Environmental Occurrence, Fate, Exposure, and Toxicity of Benzothiazoles.

    Science.gov (United States)

    Liao, Chunyang; Kim, Un-Jung; Kannan, Kurunthachalam

    2018-05-01

    Benzothiazole and its derivatives (BTs) are high production volume chemicals that have been used for several decades in a large number of industrial and consumer products, including vulcanization accelerators, corrosion inhibitors, fungicides, herbicides, algicides, and ultraviolet (UV) light stabilizers. Several benzothiazole derivatives are used commercially, and widespread use of these chemicals has led to ubiquitous occurrence in diverse environmental compartments. BTs have been reported to be dermal sensitizers, respiratory tract irritants, endocrine disruptors, carcinogens, and genotoxicants. This article reviews occurrence and fate of a select group of BTs in the environment, as well as human exposure and toxicity. BTs have frequently been found in various environmental matrices at concentrations ranging from sub-ng/L (surface water) to several tens of μg/g (indoor dust). The use of BTs in a number of consumer products, especially in rubber products, has resulted in widespread human exposure. BTs undergo chemical, biological, and photolytic degradation in the environment, creating several transformation products. Of these, 2-thiocyanomethylthio-benzothiazole (2-SCNMeS-BTH) has been shown to be the most toxic. Epidemiological studies have shown excess risks of cancers, including bladder cancer, lung cancer, and leukemia, among rubber factory workers, particularly those exposed to 2-mercapto-benzothiazole (2-SH-BTH). Human exposure to BTs continues to be a concern.

  15. Environmental properties of long chain alcohols. Part 1: Physicochemical, environmental fate and acute aquatic toxicity properties

    DEFF Research Database (Denmark)

    Fisk, Peter; Sanderson, Hans; Wildey, Ross

    2009-01-01

    )SARs). This allows predictions of data relating to human and environmental safety profiles and patterns. These alcohols have been shown to be rapidly degradable under standard conditions up to C18. Furthermore, evidence suggests that longer chain lengths are also rapidly biodegradable. While log Kow values suggest...

  16. Modelling the fate of oxidisable organic contaminants in groundwater

    DEFF Research Database (Denmark)

    Barry, D.A.; Prommer, H.; Miller, C.T.

    2002-01-01

    modelling framework is illustrated by pertinent examples, showing the degradation of dissolved organics by microbial activity limited by the availability of nutrients or electron acceptors (i.e., changing redox states), as well as concomitant secondary reactions. Two field-scale modelling examples......Subsurface contamination by organic chemicals is a pervasive environmental problem, susceptible to remediation by natural or enhanced attenuation approaches or more highly engineered methods such as pump-and-treat, amongst others. Such remediation approaches, along with risk assessment...... are discussed, the Vejen landfill (Denmark) and an example where metal contamination is remediated by redox changes wrought by injection of a dissolved organic compound. A summary is provided of current and likely future challenges to modelling of oxidisable organics in the subsurface. (C) 2002 Elsevier Science...

  17. Modeling environmental policy

    International Nuclear Information System (INIS)

    Martin, W.E.; McDonald, L.A.

    1997-01-01

    The eight book chapters demonstrate the link between the physical models of the environment and the policy analysis in support of policy making. Each chapter addresses an environmental policy issue using a quantitative modeling approach. The volume addresses three general areas of environmental policy - non-point source pollution in the agricultural sector, pollution generated in the extractive industries, and transboundary pollutants from burning fossil fuels. The book concludes by discussing the modeling efforts and the use of mathematical models in general. Chapters are entitled: modeling environmental policy: an introduction; modeling nonpoint source pollution in an integrated system (agri-ecological); modeling environmental and trade policy linkages: the case of EU and US agriculture; modeling ecosystem constraints in the Clean Water Act: a case study in Clearwater National Forest (subject to discharge from metal mining waste); costs and benefits of coke oven emission controls; modeling equilibria and risk under global environmental constraints (discussing energy and environmental interrelations); relative contribution of the enhanced greenhouse effect on the coastal changes in Louisiana; and the use of mathematical models in policy evaluations: comments. The paper on coke area emission controls has been abstracted separately for the IEA Coal Research CD-ROM

  18. Environmental properties of long chain alcohols. Part 1: Physicochemical, environmental fate and acute aquatic toxicity properties

    DEFF Research Database (Denmark)

    Fisk, Peter; Sanderson, Hans; Wildey, Ross

    2009-01-01

    )SARs). This allows predictions of data relating to human and environmental safety profiles and patterns. These alcohols have been shown to be rapidly degradable under standard conditions up to C18. Furthermore, evidence suggests that longer chain lengths are also rapidly biodegradable. While log Kow values suggest......This paper summarises the physicochemical, biodegradation and acute aquatic ecotoxicity properties of long chain aliphatic alcohols. Properties of pure compounds are shown to follow somewhat predictable trends, which are amenable to estimation by quantitative structure-activity relationships ((Q...

  19. An Evaluation of the Environmental Fate and Behavior of Munitions Material (TNT, RDX) in Soil and Plant Systems. Environmental Fate and Behavior of RDX

    Science.gov (United States)

    1990-08-01

    2.2 2.2 SOIL CHARACTERIZATION AND SAMPLING ............................................. 2.7 2.3 PLANT CULTIVATION ...cycle. 2.3 Plant Cultivation and Samoling The chemical fate of RDX in plants was evaluated using bush beans K (Phaseolus vulgaris), wheat (Triticum...particularly in light of the high tissue concentrations observed, may be important from the standpoint of food-chain transfer and ecotoxicology

  20. 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).

  1. Fate and Transport of Mercury in Environmental Media and Human Exposure

    Science.gov (United States)

    Kim, Moon-Kyung

    2012-01-01

    Mercury is emitted to the atmosphere from various natural and anthropogenic sources, and degrades with difficulty in the environment. Mercury exists as various species, mainly elemental (Hg0) and divalent (Hg2+) mercury depending on its oxidation states in air and water. Mercury emitted to the atmosphere can be deposited into aqueous environments by wet and dry depositions, and some can be re-emitted into the atmosphere. The deposited mercury species, mainly Hg2+, can react with various organic compounds in water and sediment by biotic reactions mediated by sulfur-reducing bacteria, and abiotic reactions mediated by sunlight photolysis, resulting in conversion into organic mercury such as methylmercury (MeHg). MeHg can be bioaccumulated through the food web in the ecosystem, finally exposing humans who consume fish. For a better understanding of how humans are exposed to mercury in the environment, this review paper summarizes the mechanisms of emission, fate and transport, speciation chemistry, bioaccumulation, levels of contamination in environmental media, and finally exposure assessment of humans. PMID:23230463

  2. Environmental effect and fate of selected phenols in aquatic ecosystems using microcosm approaches

    International Nuclear Information System (INIS)

    Portier, R.J.; Chen, H.M.; Meyers, S.P.

    1983-01-01

    Microbiological studies, together with physicochemical analyses of selected industrial source phenols of environmental significance, were conducted in continuous flow and carbon metabolism microcosms to determine the behavior of these priority pollutants in soil and sediment-water systems typical of coastal wetlands. Phenols used included 4- nitrophenol, 2,4,6-trichlorophenol, 2-chlorophenol, and phenol. The organophosphate, 14 C-UL-Methyl Parathion, was used as a benchmark toxicant control while 14 C-Ring-Phenol was employed for all phenolic compound additions. Microbial diversity, ATP, and specific enzyme systems (i.e., phosphatase, dehydrogenase) were continuously monitored along with 14 CO 2 expiration and 14 C assimilation by the cellular component. Residual analysis of all microcosm tests employed procedures using combined gas chromatography/high-performance liquid chromatography. Statistical analyses were conducted of variations of testing criteria, along with a ranking profile of relative biotransformation and biodegradation potential. Data presented confirm the validity of microcosm approaches and related correlation analysis in toxic substance fate investigations. 17 references, 6 figures, 1 table

  3. The fate of cyanide in leach wastes at gold mines: an environmental perspective

    Science.gov (United States)

    Johnson, Craig A.

    2015-01-01

    This paper reviews the basic chemistry of cyanide, methods by which cyanide can be analyzed, and aspects of cyanide behavior that are most relevant to environmental considerations at mineral processing operations associated with gold mines. The emphasis is on research results reported since 1999 and on data gathered for a series of U.S. Geological Survey studies that began in the late 1990s. Cyanide is added to process solutions as the CN− anion, but ore leaching produces numerous other cyanide-containing and cyanide-related species in addition to the desired cyanocomplex of gold. These can include hydrogen cyanide (HCN); cyanometallic complexes of iron, copper, zinc, nickel, and many other metals; cyanate (CNO−); and thiocyanate (SCN−). The fate of these species in solid wastes and residual process solutions that remain once gold recovery activities are terminated and in any water that moves beyond the ore processing facility dictates the degree to which cyanide poses a risk to aquatic organisms and aquatic-dependent organisms in the local environment.

  4. Large-scale modeling on the fate and transport of polycyclic aromatic hydrocarbons (PAHs) in multimedia over China

    Science.gov (United States)

    Huang, Y.; Liu, M.; Wada, Y.; He, X.; Sun, X.

    2017-12-01

    In recent decades, with rapid economic growth, industrial development and urbanization, expanding pollution of polycyclic aromatic hydrocarbons (PAHs) has become a diversified and complicated phenomenon in China. However, the availability of sufficient monitoring activities for PAHs in multi-compartment and the corresponding multi-interface migration processes are still limited, especially at a large geographic area. In this study, we couple the Multimedia Fate Model (MFM) to the Community Multi-Scale Air Quality (CMAQ) model in order to consider the fugacity and the transient contamination processes. This coupled dynamic contaminant model can evaluate the detailed local variations and mass fluxes of PAHs in different environmental media (e.g., air, surface film, soil, sediment, water and vegetation) across different spatial (a county to country) and temporal (days to years) scales. This model has been applied to a large geographical domain of China at a 36 km by 36 km grid resolution. The model considers response characteristics of typical environmental medium to complex underlying surface. Results suggest that direct emission is the main input pathway of PAHs entering the atmosphere, while advection is the main outward flow of pollutants from the environment. In addition, both soil and sediment act as the main sink of PAHs and have the longest retention time. Importantly, the highest PAHs loadings are found in urbanized and densely populated regions of China, such as Yangtze River Delta and Pearl River Delta. This model can provide a good scientific basis towards a better understanding of the large-scale dynamics of environmental pollutants for land conservation and sustainable development. In a next step, the dynamic contaminant model will be integrated with the continental-scale hydrological and water resources model (i.e., Community Water Model, CWatM) to quantify a more accurate representation and feedbacks between the hydrological cycle and water quality at

  5. Multimedia fate modeling and risk assessment of a commonly used azole fungicide climbazole at the river basin scale in China.

    Science.gov (United States)

    Zhang, Qian-Qian; Ying, Guang-Guo; Chen, Zhi-Feng; Liu, You-Sheng; Liu, Wang-Rong; Zhao, Jian-Liang

    2015-07-01

    Climbazole is an antidandruff active ingredient commonly used in personal care products, but little is known about its environmental fate. The aim of this study was to evaluate the fate of climbazole in water, sediment, soil and air compartments of the whole China by using a level III multimedia fugacity model. The usage of climbazole was calculated to be 345 t in the whole China according to the market research data, and after wastewater treatment a total emission of 245 t was discharged into the receiving environment with approximately 93% into the water compartment and 7% into the soil compartment. The developed fugacity model was successfully applied to estimate the contamination levels and mass inventories of climbazole in various environmental compartments of the river basins in China. The predicted environmental concentration ranges of climbazole were: 0.20-367 ng/L in water, and 0.009-25.2 ng/g dry weight in sediment. The highest concentration was mainly found in Haihe River basin and the lowest was in basins of Tibet and Xinjiang regions. The mass inventory of climbazole in the whole China was estimated to be 294 t, with 6.79% in water, 83.7% in sediment, 9.49% in soil, and 0.002% in air. Preliminary risk assessment showed high risks in sediment posed by climbazole in 2 out of 58 basins in China. The medium risks in water and sediment were mostly concentrated in north China. To the best of our knowledge, it is the first report on the emissions and multimedia fate of climbazole in the river basins of the whole China. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Modelling micro-pollutant fate in wastewater collection and treatment systems: status and challenges

    DEFF Research Database (Denmark)

    Plósz, Benedek G.; Benedetti, L.; Daigger, G. T.

    2013-01-01

    of such models. In brief, we conclude that, in order to predict the contaminant removal in centralised treatment works, considering the dramatic improvement in monitoring and detecting MPs in wastewater, more mechanistic approaches should be used to complement conventional, heuristic and other fate models...

  7. 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...... approach; and, iii) future pathways to improve the overall modelling of micropollutants...

  8. Uncertainty quantification for environmental models

    Science.gov (United States)

    Hill, Mary C.; Lu, Dan; Kavetski, Dmitri; Clark, Martyn P.; Ye, Ming

    2012-01-01

    Environmental models are used to evaluate the fate of fertilizers in agricultural settings (including soil denitrification), the degradation of hydrocarbons at spill sites, and water supply for people and ecosystems in small to large basins and cities—to mention but a few applications of these models. They also play a role in understanding and diagnosing potential environmental impacts of global climate change. The models are typically mildly to extremely nonlinear. The persistent demand for enhanced dynamics and resolution to improve model realism [17] means that lengthy individual model execution times will remain common, notwithstanding continued enhancements in computer power. In addition, high-dimensional parameter spaces are often defined, which increases the number of model runs required to quantify uncertainty [2]. Some environmental modeling projects have access to extensive funding and computational resources; many do not. The many recent studies of uncertainty quantification in environmental model predictions have focused on uncertainties related to data error and sparsity of data, expert judgment expressed mathematically through prior information, poorly known parameter values, and model structure (see, for example, [1,7,9,10,13,18]). Approaches for quantifying uncertainty include frequentist (potentially with prior information [7,9]), Bayesian [13,18,19], and likelihood-based. A few of the numerous methods, including some sensitivity and inverse methods with consequences for understanding and quantifying uncertainty, are as follows: Bayesian hierarchical modeling and Bayesian model averaging; single-objective optimization with error-based weighting [7] and multi-objective optimization [3]; methods based on local derivatives [2,7,10]; screening methods like OAT (one at a time) and the method of Morris [14]; FAST (Fourier amplitude sensitivity testing) [14]; the Sobol' method [14]; randomized maximum likelihood [10]; Markov chain Monte Carlo (MCMC) [10

  9. From consumption to harvest: Environmental fate prediction of excreted ionizable trace organic chemicals

    DEFF Research Database (Denmark)

    Polesel, Fabio; Plósz, Benedek G.; Trapp, Stefan

    2015-01-01

    Excreted trace organic chemicals, e.g., pharmaceuticals and biocides, typically undergo incomplete elimination in municipal wastewater treatment plants (WWTPs) and are released to surface water via treated effluents and to agricultural soils through sludge amendment and/or irrigation with freshwa......Excreted trace organic chemicals, e.g., pharmaceuticals and biocides, typically undergo incomplete elimination in municipal wastewater treatment plants (WWTPs) and are released to surface water via treated effluents and to agricultural soils through sludge amendment and/or irrigation...... with freshwater or reclaimed wastewater. Recent research has shown the tendency for these substances to accumulate in food crops. In this study, we developed and applied a simulation tool to predict the fate of three ionizable trace chemicals (triclosan-TCS, furosemide-FUR, ciprofloxacin-CIP) from human...... and a recently developed dynamic soil-plant uptake model. The simulation tool was tested using country-specific (e.g., consumption/emission rates, precipitation and temperature) input data. A Monte Carlo-based approach was adopted to account for the uncertainty associated to physico-chemical and biokinetic model...

  10. Environmental fate and transport of nitroglycerin from propellant residues at firing positions in the unsaturated zone

    Energy Technology Data Exchange (ETDEWEB)

    Bellavance-Godin, A. [Institut National de la Recherche Scientifique, Quebec, PQ (Canada). Eau, Terre et Environnement; Martel, R. [Institut National de la Recherche Scientifique, Varennes, PQ (Canada). Eau, Terre et Environnement, Earth Sciences

    2008-07-01

    In response to environmental concerns, the Canadian Forces Base (CFB) have initiated studies to better evaluate the impact of various military activities. This paper presented the results of a study in which the fate of propellant residues on large soil columns was investigated. The sites selected for the study were the antitank ranges at Garrison Valcartier, Quebec and those at the CFB Petawawa, Ontario. The shoulder rockets fired on those ranges were propelled by solid propellants based on a nitrocellulose matrix in which nitroglycerine and ammonium perchlorate were dispersed as oxidizer and energetic materials. Propellant residues accumulated in the surface soils because the combustion processes in the rockets was incomplete. This study evaluated the contaminants transport through the unsaturated zone. Sampling was conducted in 2 steps. The first involved collecting uncontaminated soil samples representative of the geological formations of the 2 sites. The second step involved collecting soils containing high levels of propellant residues behind antitank firing positions, which was later spread across the surface of the uncontaminated soil columns and which were representative of the contaminated zone. The soils were watered in the laboratory following the precipitation patterns of the respective regions and interstitial water output of the columns was also sampled. The compounds of interest were nitroglycerine and its degradation metabolites, dinitroglycerine, mononitroglycerine and nitrates as well as perchlorate and bromides. Results presented high concentrations of nitrites, nitrates and perchlorates. Both the NG and its degradation products were monitored using a newly developed analytical method that provides for a better understanding of NG degradation pathways in anaerobic conditions. 12 refs., 3 tabs., 12 figs.

  11. Source apportionment and environmental fate of lead chromates in atmospheric dust in arid environments.

    Science.gov (United States)

    Meza-Figueroa, Diana; González-Grijalva, Belem; Romero, Francisco; Ruiz, Joaquin; Pedroza-Montero, Martín; Rivero, Carlos Ibañez-Del; Acosta-Elías, Mónica; Ochoa-Landin, Lucas; Navarro-Espinoza, Sofía

    2018-03-07

    The environmental fate of lead derived from traffic paint has been poorly studied in developing countries, mainly in arid zones. For this purpose, a developing city located in the Sonoran desert (Hermosillo, Mexico), was chosen to conduct a study. In this paper the lead chromate (crocoite) sources in atmospheric dust were addressed using a combination of Raman microspectroscopy, X-ray diffraction, scanning electron microscopy (SEM), and Pb isotope measurements. A high concentration of Pb and Cr as micro- and nanostructured pigments of crocoite is reported in yellow traffic paint (n=80), road dust (n=146), settled dust in roofs (n=21), and atmospheric dust (n=20) from a developing city located in the Sonoran Desert. 10 samples of peri-urban soils were collected for local geochemical background. The paint photodegradation and erosion of the asphaltic cover are enhanced by the climate, and the presence of the mineral crocoite (PbCrO 4 ) in road dust with an aerodynamic diameter ranging from 100nm to 2μm suggests its integration into the atmosphere by wind resuspension processes. A positive PbCr correlation (R 2 =0.977) was found for all studied samples, suggesting a common source. The Pb-isotope data show signatures in atmospheric dust as a product of the mixing of two end members: i) local soils and ii) crocoite crystals as pigments in paint. The presence of lead chromates in atmospheric dust has not been previously documented in Latin America, and it represents an unknown health risk to the exposed population because the identified size of crystals can reach the deepest part of lungs. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Assessment of the environmental fate of cycloxaprid in flooded and anaerobic soils by radioisotopic tracing

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xuanqi; Xu, Xiaoyong; Li, Chao [Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China, University of Science and Technology, Shanghai 200237 (China); Zhang, Hanxue; Fu, Qiuguo [Institute of Nuclear Agricultural Sciences, Zhejiang University, Hangzhou 310029 (China); Shao, Xusheng [Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China, University of Science and Technology, Shanghai 200237 (China); Ye, Qingfu, E-mail: qfye@zju.edu.cn [Institute of Nuclear Agricultural Sciences, Zhejiang University, Hangzhou 310029 (China); Li, Zhong, E-mail: lizhong@ecust.edu.cn [Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China, University of Science and Technology, Shanghai 200237 (China)

    2016-02-01

    Cycloxaprid (CYC) is a novel broad-spectrum neonicotinoid insecticide that has been developed for agricultural pest control. The fate of the {sup 14}C-labeled racemic and enantio-pure CYC isomers in flooded and anaerobic soil was investigated using radioisotope tracing techniques. After 100 d of incubation, only a minor portion (< 1%) of the applied CYC isomers is mineralized by each of the four tested soil types. The fraction of initially applied radioactive CYC dissipated into the bound or non-extractable residues (BR) increases with increase in the length of the incubation period, reaching up to 53.0–81.6%. The dissipation of the CYC through mineralization or formation of BR is strongly influenced by soil properties, such as humic content, pH value, and retained microbial activity. Amongst the soils studied, the fluvio-marine yellow loamy soil displayed the highest tendency to mineralize CYC while the coastal saline soil exhibited the strongest tendency to form BR. The observation that the water phase retained the large portion(> 60%) of the radioactivity attributed to the total extractable residue suggested that under the experimental condition, the initially applied {sup 14}C-labeled CYC residues were readily available for leaching or offsite transport. Additionally, no enantiomer-specific behaviors are observed. The results from this study provide a framework for assessing the environmental impact resulting from the use of this pesticide. - Highlights: • Only a minor portion (<1%) of the applied CYC was mineralized. • The bound residue increased over time, reaching up to 53.0-81.6%. • CYC residues were readily available for leaching. • No enantiomer-specific behaviors were observed.

  13. Modeling bistable cell-fate choices in the Drosophila eye: qualitative and quantitative perspectives

    Science.gov (United States)

    Graham, Thomas G. W.; Tabei, S. M. Ali; Dinner, Aaron R.; Rebay, Ilaria

    2010-01-01

    A major goal of developmental biology is to understand the molecular mechanisms whereby genetic signaling networks establish and maintain distinct cell types within multicellular organisms. Here, we review cell-fate decisions in the developing eye of Drosophila melanogaster and the experimental results that have revealed the topology of the underlying signaling circuitries. We then propose that switch-like network motifs based on positive feedback play a central role in cell-fate choice, and discuss how mathematical modeling can be used to understand and predict the bistable or multistable behavior of such networks. PMID:20570936

  14. The role of direct photolysis and indirect photochemistry in the environmental fate of ethylhexyl methoxy cinnamate (EHMC) in surface waters.

    Science.gov (United States)

    Vione, D; Calza, P; Galli, F; Fabbri, D; Santoro, V; Medana, C

    2015-12-15

    The aquatic environmental fate of ethylhexyl methoxy cinnamate (EHMC), one of the most used UVB filters worldwide, was studied by assessing its environmental persistence and photoinduced transformations. The role of direct and indirect photolysis was evaluated. Direct photolysis was shown to play a key role, and this process is expected to be the main attenuation route of EHMC in sunlit surface waters. In contrast, the reaction with OH radicals would be negligible and that with (3)CDOM* would at most be a secondary process. The measurement of the quantum yield of direct photolysis and of the rate constants of reaction with photogenerated transient species (or, sometimes, the use of reasonable values for the latter) allowed the prediction of the EHMC half-life time in surface waters, by means of a validated photochemical model. The predicted EHMC lifetime is of the order of hours to a few days in fair-weather summertime, and the main factors controlling the EHMC phototransformation in sunlit surface waters would be the water depth and the dissolved organic carbon (DOC) content. The formation of transformation products (TPs) was followed as well via HPLC/HRMS. Three TPs were detected in the samples exposed to UVA radiation, while one additional TP was detected in the samples exposed to UVB radiation. The detected TPs comprised 4-methoxybenzaldehyde, a hydroxylated derivative and dimeric species. Through the use of heterogeneous photocatalysis with TiO2, seven additional TPs were identified, most of them resulting from the further degradation of primary TPs formed through direct photolysis and that might be detected in aquatic systems as well. The photodegradation of EHMC in the presence of TiO2 yielded more toxic TPs than the parent compound (as determined with the Vibrio fischeri Microtox assay). The increased toxicity is partially accounted for by the formation of 4-methoxybenzaldehyde. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Multimedia fate modeling of perfluorooctanoic acid (PFOA) and perfluorooctane sulphonate (PFOS) in the shallow lake Chaohu, China.

    Science.gov (United States)

    Kong, Xiangzhen; Liu, Wenxiu; He, Wei; Xu, Fuliu; Koelmans, Albert A; Mooij, Wolf M

    2018-06-01

    Freshwater shallow lake ecosystems provide valuable ecological services to human beings. However, these systems are subject to severe contamination from anthropogenic sources. Per- and polyfluoroalkyl substances (PFASs), including perfluorooctanoic acid (PFOA) and perfluorooctane sulphonate (PFOS), are among the contaminants that have received substantial attention, primarily due to abundant applications, environment persistence, and potential threats to ecological and human health. Understanding the environmental behavior of these contaminants in shallow freshwater lake environments using a modeling approach is therefore critical. Here, we characterize the fate, transport and transformation of both PFOA and PFOS in the fifth largest freshwater lake in China (Chaohu) during a two-year period (2013-2015) using a fugacity-based multimedia fate model. A reasonable agreement between the measured and modeled concentrations in various compartments confirms the model's reliability. The model successfully quantifies the environmental processes and identifies the major sources and input pathways of PFOA and PFOS to the Chaohu water body. Sensitivity analysis reveals the critical role of nonlinear Freundlich sorption, which contributes to a variable fraction of the model true uncertainty in different compartments (8.1%-93.6%). Through additional model scenario analyses, we further elucidate the importance of nonlinear Freundlich sorption that is essential for the reliable model performance. We also reveal the distinct composition of emission sources for the two contaminants, as the major sources are indirect soil volatilization and direct release from human activities for PFOA and PFOS, respectively. The present study is expected to provide implications for local management of PFASs pollution in Lake Chaohu and to contribute to developing a general model framework for the evaluation of PFASs in shallow lakes. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Prediction of overall persistence and long-range transport potential with multimedia fate models: robustness and sensitivity of results

    International Nuclear Information System (INIS)

    Fenner, Kathrin; Scheringer, Martin; Hungerbuehler, Konrad

    2004-01-01

    The hazard indicators persistence (P) and long-range transport potential (LRTP) are used in chemicals assessment to characterize chemicals with regard to the temporal and spatial extent of their environmental exposure. They are often calculated based on the results of multimedia fate models. The environmental and substance-specific input parameters of such models are subject to a range of methodological uncertainties and also influenced by natural variability. We employed probabilistic uncertainty analysis to quantify variance in P and LRTP predictions for chemicals with different partitioning and transport behavior. Variance found in the results is so large that it prevents a clear distinction between chemicals. Additionally, only small improvements are observed when evaluating the results relative to a benchmark chemical. This can be explained by the dominance of substance-specific parameters and the only small direct influence of environmental parameters on P and LRTP as model outcomes. The findings underline the importance of learning how environmental conditions cause variability in substance behavior for improved substance ranking and classification. - Environmental conditions cause variability in substance behavior which need to be considered in chemical ranking schemes

  17. 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

  18. 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, ...

  19. Parameters for the Evaluation of the Fate, Transport, and Environmental Impacts of Chemical Agents in Marine Environments

    Science.gov (United States)

    2007-07-01

    Anal. Bering/Chukchi, accessed 3 January 2007, http://www.osdpd.noaa.gov/PSB/EPS/SST/data/beringst.c.gif. RE-2 15 Brewer , P. G.; Glover, D. M...Highly Purified Mustard Gas and its Action on Yeast , ” J. Am. Chem. Soc., 1947, 69(7), 1808-1809. 135 Redemann, C. E.; Chaikin, S. W.; Fearing, R. B...171 MacNaughton, M. G.; Brewer , J. H., Environmental Chemistry and Fate of Chemical Warfare Agents, Southwest Research Institute, San Antonio TX, 1994

  20. Estimating demographic parameters using a combination of known-fate and open N-mixture models.

    Science.gov (United States)

    Schmidt, Joshua H; Johnson, Devin S; Lindberg, Mark S; Adams, Layne G

    2015-10-01

    Accurate estimates of demographic parameters are required to infer appropriate ecological relationships and inform management actions. Known-fate data from marked individuals are commonly used to estimate survival rates, whereas N-mixture models use count data from unmarked individuals to estimate multiple demographic parameters. However, a joint approach combining the strengths of both analytical tools has not been developed. Here we develop an integrated model combining known-fate and open N-mixture models, allowing the estimation of detection probability, recruitment, and the joint estimation of survival. We demonstrate our approach through both simulations and an applied example using four years of known-fate and pack count data for wolves (Canis lupus). Simulation results indicated that the integrated model reliably recovered parameters with no evidence of bias, and survival estimates were more precise under the joint model. Results from the applied example indicated that the marked sample of wolves was biased toward individuals with higher apparent survival rates than the unmarked pack mates, suggesting that joint estimates may be more representative of the overall population. Our integrated model is a practical approach for reducing bias while increasing precision and the amount of information gained from mark-resight data sets. We provide implementations in both the BUGS language and an R package.

  1. Characterization of the Flow Field and Wind Speed Profiles in Microbalance Wind Tunnels for Measurement of Agent Fate

    National Research Council Canada - National Science Library

    Weber, Daniel J; Molnar, John W; Scudder, Mary K; Shuely, Wendel

    2005-01-01

    An important goal is to model chemical warfare agent fate on environmental and interior surfaces and therefore, rigorously measured evaporation and desorption rates are required to develop equations...

  2. Enantioselective stable isotope analysis (ESIA) — A new concept to evaluate the environmental fate of chiral organic contaminants

    International Nuclear Information System (INIS)

    Badea, Silviu-Laurentiu; Danet, Andrei-Florin

    2015-01-01

    Since 2011, the enantiospecific stable carbon isotope analysis (ESIA) has emerged as an innovative technique to assess the environmental fate of chiral emerging compounds by combining in one experimental technique both compound specific isotope analysis (CSIA) and enantioselective analysis. To date, the ESIA was applied for four classes of compounds: α-hexachlorocyclohexane (α-HCH), polar herbicides (phenoxy acids), synthetic polycyclic musk galaxolide (HHCB), and phenoxyalkanoic methyl herbicides. From an analytical point of view there are factors that are hindering the application of ESIA methods for the field samples: (i.e. amounts of target analyte, matrix effects, GC resolution) and overcoming these factors is challenging. While ESIA was shown as a mature technique for the first three abovementioned class of compounds, no isotope analysis of individual enantiomers could be performed for phenoxyalkanoic methyl herbicides. With respect to field studies, one study showed that ESIA might be a promising tool to distinguish between biotic and abiotic transformation pathways of chiral organic contaminants and even to differentiate between their aerobic and anaerobic biotransformation pathways. The development of ESIA methods for new chiral emerging contaminants in combination with development of multi-element isotope analysis will contribute to a better characterization of transformation pathways of chiral organic contaminants. - Highlights: • ESIA is an innovative technique to assess the environmental fate of chiral pollutants • Overcoming the analytical limitations of ESIA is challenging • Development of ESIA methods for new chiral emerging contaminants is needed

  3. Enantioselective stable isotope analysis (ESIA) — A new concept to evaluate the environmental fate of chiral organic contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Badea, Silviu-Laurentiu, E-mail: badeasilviu@gmail.com [Department of Chemistry, Umeå University, SE-901 87 Umeå (Sweden); Danet, Andrei-Florin [Department of Analytical Chemistry, University of Bucharest, Faculty of Chemistry, 90-92 Panduri Str., Bucharest 050657 (Romania)

    2015-05-01

    Since 2011, the enantiospecific stable carbon isotope analysis (ESIA) has emerged as an innovative technique to assess the environmental fate of chiral emerging compounds by combining in one experimental technique both compound specific isotope analysis (CSIA) and enantioselective analysis. To date, the ESIA was applied for four classes of compounds: α-hexachlorocyclohexane (α-HCH), polar herbicides (phenoxy acids), synthetic polycyclic musk galaxolide (HHCB), and phenoxyalkanoic methyl herbicides. From an analytical point of view there are factors that are hindering the application of ESIA methods for the field samples: (i.e. amounts of target analyte, matrix effects, GC resolution) and overcoming these factors is challenging. While ESIA was shown as a mature technique for the first three abovementioned class of compounds, no isotope analysis of individual enantiomers could be performed for phenoxyalkanoic methyl herbicides. With respect to field studies, one study showed that ESIA might be a promising tool to distinguish between biotic and abiotic transformation pathways of chiral organic contaminants and even to differentiate between their aerobic and anaerobic biotransformation pathways. The development of ESIA methods for new chiral emerging contaminants in combination with development of multi-element isotope analysis will contribute to a better characterization of transformation pathways of chiral organic contaminants. - Highlights: • ESIA is an innovative technique to assess the environmental fate of chiral pollutants • Overcoming the analytical limitations of ESIA is challenging • Development of ESIA methods for new chiral emerging contaminants is needed.

  4. Polycyclic aromatic hydrocarbons - fate and long-range atmospheric transport studied using a global model, EMAC-SVOC

    Science.gov (United States)

    Octaviani, Mega; Tost, Holger; Lammel, Gerhard

    2017-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are emitted by incomplete combustion from fossil fuel, vehicles, and biomass burning. They may persist in environmental compartments, pose a health hazard and may bio accumulate along food chains. The ECHAM/MESSy Atmospheric Chemistry (EMAC) model had been used to simulate global tropospheric, stratospheric chemistry and climate. In this study, we improve the model to include simulations of the transport and fate of semi-volatile organic compounds (SVOC). The EMAC-SVOC model takes into account essential environmental processes including gas-particle partitioning, dry and wet deposition, chemical and bio-degradation, and volatilization from sea surface, soils, vegetation, and snow. The model was evaluated against observational data in the Arctic, mid-latitudes, and tropics, and further applied to study total environmental lifetime and long-range transport potential (LRTP) of PAHs. We selected four compounds for study, spanning a wide range of volatility, i.e., phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene. Several LRTP indicators were investigated, including the Arctic contamination potential, meridional spreading, and zonal and meridional fluxes to remote regions.

  5. The role of direct photolysis and indirect photochemistry in the environmental fate of ethylhexyl methoxy cinnamate (EHMC) in surface waters

    International Nuclear Information System (INIS)

    Vione, D.; Calza, P.; Galli, F.; Fabbri, D.; Santoro, V.; Medana, C.

    2015-01-01

    The aquatic environmental fate of ethylhexyl methoxy cinnamate (EHMC), one of the most used UVB filters worldwide, was studied by assessing its environmental persistence and photoinduced transformations. The role of direct and indirect photolysis was evaluated. Direct photolysis was shown to play a key role, and this process is expected to be the main attenuation route of EHMC in sunlit surface waters. In contrast, the reaction with ·OH radicals would be negligible and that with "3CDOM* would at most be a secondary process. The measurement of the quantum yield of direct photolysis and of the rate constants of reaction with photogenerated transient species (or, sometimes, the use of reasonable values for the latter) allowed the prediction of the EHMC half-life time in surface waters, by means of a validated photochemical model. The predicted EHMC lifetime is of the order of hours to a few days in fair-weather summertime, and the main factors controlling the EHMC phototransformation in sunlit surface waters would be the water depth and the dissolved organic carbon (DOC) content. The formation of transformation products (TPs) was followed as well via HPLC/HRMS. Three TPs were detected in the samples exposed to UVA radiation, while one additional TP was detected in the samples exposed to UVB radiation. The detected TPs comprised 4-methoxybenzaldehyde, a hydroxylated derivative and dimeric species. Through the use of heterogeneous photocatalysis with TiO_2, seven additional TPs were identified, most of them resulting from the further degradation of primary TPs formed through direct photolysis and that might be detected in aquatic systems as well. The photodegradation of EHMC in the presence of TiO_2 yielded more toxic TPs than the parent compound (as determined with the Vibrio fischeri Microtox assay). The increased toxicity is partially accounted for by the formation of 4-methoxybenzaldehyde. - Highlights: • Study of the photolytic and photocatalytic transformation

  6. The role of direct photolysis and indirect photochemistry in the environmental fate of ethylhexyl methoxy cinnamate (EHMC) in surface waters

    Energy Technology Data Exchange (ETDEWEB)

    Vione, D. [Department of Chemistry, University of Torino, via P. Giuria 5, 10125 Torino (Italy); Calza, P., E-mail: paola.calza@unito.it [Department of Chemistry, University of Torino, via P. Giuria 5, 10125 Torino (Italy); Galli, F.; Fabbri, D. [Department of Chemistry, University of Torino, via P. Giuria 5, 10125 Torino (Italy); Santoro, V.; Medana, C. [Department of Molecular Biotechnology and Health Sciences, University of Torino, via P. Giuria 5, 10125 Torino (Italy)

    2015-12-15

    The aquatic environmental fate of ethylhexyl methoxy cinnamate (EHMC), one of the most used UVB filters worldwide, was studied by assessing its environmental persistence and photoinduced transformations. The role of direct and indirect photolysis was evaluated. Direct photolysis was shown to play a key role, and this process is expected to be the main attenuation route of EHMC in sunlit surface waters. In contrast, the reaction with ·OH radicals would be negligible and that with {sup 3}CDOM* would at most be a secondary process. The measurement of the quantum yield of direct photolysis and of the rate constants of reaction with photogenerated transient species (or, sometimes, the use of reasonable values for the latter) allowed the prediction of the EHMC half-life time in surface waters, by means of a validated photochemical model. The predicted EHMC lifetime is of the order of hours to a few days in fair-weather summertime, and the main factors controlling the EHMC phototransformation in sunlit surface waters would be the water depth and the dissolved organic carbon (DOC) content. The formation of transformation products (TPs) was followed as well via HPLC/HRMS. Three TPs were detected in the samples exposed to UVA radiation, while one additional TP was detected in the samples exposed to UVB radiation. The detected TPs comprised 4-methoxybenzaldehyde, a hydroxylated derivative and dimeric species. Through the use of heterogeneous photocatalysis with TiO{sub 2}, seven additional TPs were identified, most of them resulting from the further degradation of primary TPs formed through direct photolysis and that might be detected in aquatic systems as well. The photodegradation of EHMC in the presence of TiO{sub 2} yielded more toxic TPs than the parent compound (as determined with the Vibrio fischeri Microtox assay). The increased toxicity is partially accounted for by the formation of 4-methoxybenzaldehyde. - Highlights: • Study of the photolytic and photocatalytic

  7. Exploring the fate, transport and risk of Perfluorooctane Sulfonate (PFOS) in a coastal region of China using a multimedia model.

    Science.gov (United States)

    Liu, Shijie; Lu, Yonglong; Xie, Shuangwei; Wang, Tieyu; Jones, Kevin C; Sweetman, Andrew J

    2015-12-01

    Perfluorooctane Sulfonate (PFOS) and related substances have been widely applied in both industrial processes and domestic products in China. Exploring the environmental fate and transport of PFOS using modeling methods provides an important link between emission and multimedia diffusion which forms a vital part in the human health risk assessment and chemical management for these substances. In this study, the gridded fugacity based BETR model was modified to make it more suitable to model transfer processes of PFOS in a coastal region, including changes to PFOS partition coefficients to reflect the influence of water salinity on its sorption behavior. The fate and transport of PFOS in the Bohai coastal region of China were simulated under steady state with the modified version of the model. Spatially distributed emissions of PFOS and related substances in 2010 were estimated and used in these simulations. Four different emission scenarios were investigated, in which a range of half-lives for PFOS related substances were considered. Concentrations of PFOS in air, vegetation, soil, fresh water, fresh water sediment and coastal water were derived from the model under the steady-state assumption. The median modeled PFOS concentrations in fresh water, fresh water sediment and soil were 7.20ng/L, 0.39ng/g and 0.21ng/g, respectively, under Emission Scenario 2 (which assumed all PFOS related substances immediately degrade to PFOS) for the whole region, while the maximum concentrations were 47.10ng/L, 4.98ng/g and 2.49ng/g, respectively. Measured concentration data for PFOS in the Bohai coastal region around the year of 2010 were collected from the literature. The reliability of the model results was evaluated by comparing the range of modeled concentrations with the measured data, which generally matched well for the main compartments. Fate and transfer fluxes were derived from the model based on the calculated inventory within the compartments, transfer fluxes between

  8. Modeling the fate of polynuclear aromatic hydrocarbons in the rhizosphere

    International Nuclear Information System (INIS)

    Santharam, S.K.; Erickson, L.E.; Fan, L.T.

    1994-01-01

    Polynuclear aromatic hydrocarbons (PAHs) are major contaminants associated with wastes from manufactured gas plants, wood treating operations, and petroleum refining; they are potentially carcinogenic and mutagenic. It has been known that vegetation can enhance the rate and extent of degradation of PAHs in contaminated soil. Plant roots release exudates capable of supplying carbon and energy to microflora for degrading PAHs. It has also been well established that the population of microorganisms in the rhizosphere is significantly greater than that in the non-vegetated soil; these microorganisms are apparently responsible for the enhanced biodegradation of PAHs. A model has been derived for describing the rate of disappearance of a non-aqueous phase contaminant in the rhizosphere, which takes into account dissolution, adsorption, desorption and biodegradation of the contaminant, without neglecting the size distribution of the organic-phase droplets; the rate of biodegradation is expressed in terms of the Monod kinetics. The model is validated with the available experimental data for pyrene

  9. Mitochondrial metabolism in early neural fate and its relevance for neuronal disease modeling.

    Science.gov (United States)

    Lorenz, Carmen; Prigione, Alessandro

    2017-12-01

    Modulation of energy metabolism is emerging as a key aspect associated with cell fate transition. The establishment of a correct metabolic program is particularly relevant for neural cells given their high bioenergetic requirements. Accordingly, diseases of the nervous system commonly involve mitochondrial impairment. Recent studies in animals and in neural derivatives of human pluripotent stem cells (PSCs) highlighted the importance of mitochondrial metabolism for neural fate decisions in health and disease. The mitochondria-based metabolic program of early neurogenesis suggests that PSC-derived neural stem cells (NSCs) may be used for modeling neurological disorders. Understanding how metabolic programming is orchestrated during neural commitment may provide important information for the development of therapies against conditions affecting neural functions, including aging and mitochondrial disorders. Copyright © 2017. Published by Elsevier Ltd.

  10. Georeferenced fate modelling of LAS in the itter stream

    DEFF Research Database (Denmark)

    Schulze, C:; Matthies, M.; Trapp, S.

    1999-01-01

    For the simulation of spatial concentration patterns of 'down-the-drain' chemicals mathematical models were coupled with a Geographic Information System (GIS) to predict concentrations in the receiving surface waters, using the detergent chemicals Linear Alkylbenzenesulfonate (LAS) and Boron and ...... in the riverine water and the water quality parameters TOC and ammonium, This study is closely linked to the ongoing project GREAT-ER. (C) 1999 Elsevier Science Ltd. All rights reserved....

  11. Analysis of TCE Fate and Transport in Karst Groundwater Systems Using Statistical Mixed Models

    Science.gov (United States)

    Anaya, A. A.; Padilla, I. Y.

    2012-12-01

    Karst groundwater systems are highly productive and provide an important fresh water resource for human development and ecological integrity. Their high productivity is often associated with conduit flow and high matrix permeability. The same characteristics that make these aquifers productive also make them highly vulnerable to contamination and a likely for contaminant exposure. Of particular interest are trichloroethylene, (TCE) and Di-(2-Ethylhexyl) phthalate (DEHP). These chemicals have been identified as potential precursors of pre-term birth, a leading cause of neonatal complications with a significant health and societal cost. Both of these contaminants have been found in the karst groundwater formations in this area of the island. The general objectives of this work are to: (1) develop fundamental knowledge and determine the processes controlling the release, mobility, persistence, and possible pathways of contaminants in karst groundwater systems, and (2) characterize transport processes in conduit and diffusion-dominated flow under base flow and storm flow conditions. The work presented herein focuses on the use of geo-hydro statistical tools to characterize flow and transport processes under different flow regimes, and their application in the analysis of fate and transport of TCE. Multidimensional, laboratory-scale Geo-Hydrobed models (GHM) were used for this purpose. The models consist of stainless-steel tanks containing karstified limestone blocks collected from the karst aquifer formation of northern Puerto Rico. The models integrates a network of sampling wells to monitor flow, pressure, and solute concentrations temporally and spatially. Experimental work entails injecting dissolved CaCl2 tracers and TCE in the upstream boundary of the GHM while monitoring TCE and tracer concentrations spatially and temporally in the limestone under different groundwater flow regimes. Analysis of the temporal and spatial concentration distributions of solutes

  12. On the fate of the Standard Model at finite temperature

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Luigi Delle; Marzo, Carlo [Università del Salento, Dipartimento di Matematica e Fisica “Ennio De Giorgi' ,Via Arnesano, 73100 Lecce (Italy); INFN - Sezione di Lecce,via Arnesano, 73100 Lecce (Italy); Urbano, Alfredo [SISSA - International School for Advanced Studies,via Bonomea 256, 34136 Trieste (Italy)

    2016-05-10

    In this paper we revisit and update the computation of thermal corrections to the stability of the electroweak vacuum in the Standard Model. At zero temperature, we make use of the full two-loop effective potential, improved by three-loop beta functions with two-loop matching conditions. At finite temperature, we include one-loop thermal corrections together with resummation of daisy diagrams. We solve numerically — both at zero and finite temperature — the bounce equation, thus providing an accurate description of the thermal tunneling. Assuming a maximum temperature in the early Universe of the order of 10{sup 18} GeV, we find that the instability bound excludes values of the top mass M{sub t}≳173.6 GeV, with M{sub h}≃125 GeV and including uncertainties on the strong coupling. We discuss the validity and temperature-dependence of this bound in the early Universe, with a special focus on the reheating phase after inflation.

  13. Sequential use of the STICS crop model and of the MACRO pesticide fate model to simulate pesticides leaching in cropping systems.

    Science.gov (United States)

    Lammoglia, Sabine-Karen; Moeys, Julien; Barriuso, Enrique; Larsbo, Mats; Marín-Benito, Jesús-María; Justes, Eric; Alletto, Lionel; Ubertosi, Marjorie; Nicolardot, Bernard; Munier-Jolain, Nicolas; Mamy, Laure

    2017-03-01

    The current challenge in sustainable agriculture is to introduce new cropping systems to reduce pesticides use in order to reduce ground and surface water contamination. However, it is difficult to carry out in situ experiments to assess the environmental impacts of pesticide use for all possible combinations of climate, crop, and soils; therefore, in silico tools are necessary. The objective of this work was to assess pesticides leaching in cropping systems coupling the performances of a crop model (STICS) and of a pesticide fate model (MACRO). STICS-MACRO has the advantage of being able to simulate pesticides fate in complex cropping systems and to consider some agricultural practices such as fertilization, mulch, or crop residues management, which cannot be accounted for with MACRO. The performance of STICS-MACRO was tested, without calibration, from measurements done in two French experimental sites with contrasted soil and climate properties. The prediction of water percolation and pesticides concentrations with STICS-MACRO was satisfactory, but it varied with the pedoclimatic context. The performance of STICS-MACRO was shown to be similar or better than that of MACRO. The improvement of the simulation of crop growth allowed better estimate of crop transpiration therefore of water balance. It also allowed better estimate of pesticide interception by the crop which was found to be crucial for the prediction of pesticides concentrations in water. STICS-MACRO is a new promising tool to improve the assessment of the environmental risks of pesticides used in cropping systems.

  14. Environmental Measurements and Modeling

    Science.gov (United States)

    Environmental measurement is any data collection activity involving the assessment of chemical, physical, or biological factors in the environment which affect human health. Learn more about these programs and tools that aid in environmental decisions

  15. Environmental fate of fungicides and other current-use pesticides in a central California estuary

    Science.gov (United States)

    Smalling, Kelly L.; Kuivila, Kathryn; Orlando, James L.; Phillips, Bryn M.; Anderson, Brian S.; Siegler, Katie; Hunt, John W.; Hamilton, Mary

    2013-01-01

    The current study documents the fate of current-use pesticides in an agriculturally-dominated central California coastal estuary by focusing on the occurrence in water, sediment and tissue of resident aquatic organisms. Three fungicides (azoxystrobin, boscalid, and pyraclostrobin), one herbicide (propyzamide) and two organophosphate insecticides (chlorpyrifos and diazinon) were detected frequently. Dissolved pesticide concentrations in the estuary corresponded to the timing of application while bed sediment pesticide concentrations correlated with the distance from potential sources. Fungicides and insecticides were detected frequently in fish and invertebrates collected near the mouth of the estuary and the contaminant profiles differed from the sediment and water collected. This is the first study to document the occurrence of many current-use pesticides, including fungicides, in tissue. Limited information is available on the uptake, accumulation and effects of current-use pesticides on non-target organisms. Additional data are needed to understand the impacts of pesticides, especially in small agriculturally-dominated estuaries.

  16. Environmental Fate of the Herbicide Fluazifop-P-butyl and Its Degradation Products in Two Loamy Agricultural Soils: A Combined Laboratory and Field Study

    DEFF Research Database (Denmark)

    Badawi, Nora; Rosenbom, Anette E.; Olsen, Preben

    2015-01-01

    The herbicide fluazifop-P-butyl (FPB) is used against grasses in agricultural crops such as potato, oilseed rape and sugar beet. Limited information is available in Scientific literature on its environmental fate, therefore extensive monitoring at two agricultural test fields was combined...

  17. Monod kinetics rather than a first-order degradation model explains atrazine fate in soil mini-columns: Implications for pesticide fate modelling

    International Nuclear Information System (INIS)

    Cheyns, K.; Mertens, J.; Diels, J.; Smolders, E.; Springael, D.

    2010-01-01

    Pesticide transport models commonly assume first-order pesticide degradation kinetics for describing reactive transport in soil. This assumption was assessed in mini-column studies with associated batch degradation tests. Soil mini-columns were irrigated with atrazine in two intermittent steps of about 30 days separated by 161 days application of artificial rain water. Atrazine concentration in the effluent peaked to that of the influent concentration after initial break-through but sharply decreased while influx was sustained, suggesting a degradation lag phase. The same pattern was displayed in the second step but peak height and percentage of atrazine recovered in the effluent were lower. A Monod model with biomass decay was successfully calibrated to this data. The model was successfully evaluated against batch degradation data and mini-column experiments at lower flow rate. The study suggested that first-order degradation models may underestimate risk of pesticide leaching if the pesticide degradation potential needs amplification during degradation. - Population dynamics of pesticide degrading population should be taken into account when predictions of pesticide fate are made to avoid underestimation of pesticide break-through towards groundwater.

  18. Integrative modelling of the influence of MAPK network on cancer cell fate decision.

    Directory of Open Access Journals (Sweden)

    Luca Grieco

    2013-10-01

    Full Text Available The Mitogen-Activated Protein Kinase (MAPK network consists of tightly interconnected signalling pathways involved in diverse cellular processes, such as cell cycle, survival, apoptosis and differentiation. Although several studies reported the involvement of these signalling cascades in cancer deregulations, the precise mechanisms underlying their influence on the balance between cell proliferation and cell death (cell fate decision in pathological circumstances remain elusive. Based on an extensive analysis of published data, we have built a comprehensive and generic reaction map for the MAPK signalling network, using CellDesigner software. In order to explore the MAPK responses to different stimuli and better understand their contributions to cell fate decision, we have considered the most crucial components and interactions and encoded them into a logical model, using the software GINsim. Our logical model analysis particularly focuses on urinary bladder cancer, where MAPK network deregulations have often been associated with specific phenotypes. To cope with the combinatorial explosion of the number of states, we have applied novel algorithms for model reduction and for the compression of state transition graphs, both implemented into the software GINsim. The results of systematic simulations for different signal combinations and network perturbations were found globally coherent with published data. In silico experiments further enabled us to delineate the roles of specific components, cross-talks and regulatory feedbacks in cell fate decision. Finally, tentative proliferative or anti-proliferative mechanisms can be connected with established bladder cancer deregulations, namely Epidermal Growth Factor Receptor (EGFR over-expression and Fibroblast Growth Factor Receptor 3 (FGFR3 activating mutations.

  19. Sediment carbon fate in phreatic karst (Part 1): Conceptual model development

    Science.gov (United States)

    Husic, A.; Fox, J.; Agouridis, C.; Currens, J.; Ford, W.; Taylor, C.

    2017-06-01

    Recent research has paid increased attention to quantifying the fate of carbon pools within fluvial networks, but few, if any, studies consider the fate of sediment organic carbon in fluviokarst systems despite that karst landscapes cover 12% of the earth's land surface. The authors develop a conceptual model of sediment carbon fate in karst terrain with specific emphasis upon phreatic karst conduits, i.e., those located below the groundwater table that have the potential to trap surface-derived sediment and turnover carbon. To assist with their conceptual model development, the authors study a phreatic system and apply a mixture of methods traditional and novel to karst studies, including electrical resistivity imaging, well drilling, instantaneous velocimetry, dye tracing, stage recording, discrete and continuous sediment and water quality sampling, and elemental and stable carbon isotope fingerprinting. Results show that the sediment transport carrying capacity of the phreatic karst water is orders of magnitude less than surface streams during storm-activated periods promoting deposition of fine sediments in the phreatic karst. However, the sediment transport carrying capacity is sustained long after the hydrologic event has ended leading to sediment resuspension and prolonged transport. The surficial fine grained laminae occurs in the subsurface karst system; but unlike surface streams, the light-limited conditions of the subsurface karst promotes constant heterotrophy leading to carbon turnover. The coupling of the hydrological processes leads to a conceptual model that frames phreatic karst as a biologically active conveyor of sediment carbon that recharges degraded organic carbon back to surface streams. For example, fluvial sediment is estimated to lose 30% of its organic carbon by mass during a one year temporary residence within the phreatic karst. It is recommended that scientists consider karst pathways when attempting to estimate organic matter stocks

  20. Sensitivity analysis of the noble gas transport and fate model: CASCADR9

    International Nuclear Information System (INIS)

    Lindstrom, F.T.; Cawlfield, D.E.; Barker, L.E.

    1994-03-01

    CASCADR9 is a desert alluvial soil site-specific noble gas transport and fate model. Input parameters for CASCADR9 are: man-made source term, background concentration of radionuclides, radon half-life, soil porosity, period of barometric pressure wave, amplitude of barometric pressure wave, and effective eddy diffusivity. Using average flux, total flow, and radon concentration at the 40 day mark as output parameters, a sensitivity analysis for CASCADR9 is carried out, under a variety of scenarios. For each scenario, the parameter to which output parameters are most sensitive are identified

  1. Modeling the fate and end-of-life phase of engineered nanomaterials in the Japanese construction sector.

    Science.gov (United States)

    Suzuki, Shinya; Part, Florian; Matsufuji, Yasushi; Huber-Humer, Marion

    2018-02-01

    To date construction materials that contain engineered nanomaterials (ENMs) are available at the markets, but at the same time very little is known about their environmental fate. Therefore, this study aimed at modeling the potential fate of ENMs by using the example of the Japanese construction sector and by conducting a dynamic material flow analysis. Expert interviews and national reports revealed that about 3920-4660 tons of ENMs are annually used for construction materials in Japan. Nanoscale TiO 2 , SiO 2 , Al 2 O 3 and carbon black have already been applied for decades to wall paints, road markings or concrete. The dynamic material flow model indicates that in 2016 about 95% of ENMs, which have been used since their year of market penetration, remained in buildings, whereas only 5% ended up in the Japanese waste management system or were diffusely released into the environment. Considering the current Japanese waste management system, ENMs were predicted to end up in recycled materials (40-47%) or in landfills (36-41%). It was estimated that only a small proportion was used in agriculture (5-7%, as ENM-containing sewage sludges) or was diffusely released into soils, surface waters or the atmosphere (5-19%). The results indicate that ENM release predominantly depend on their specific applications and characteristics. The model also highlights the importance of adequate collection and treatment of ENM-containing wastes. In future, similar dynamic flow models for other countries should consider, inasmuch as available, historical data on ENM production (e.g. like declaration reports that are annually published by relevant public authorities or associations), as such input data is very important regarding data reliability in order to decrease uncertainties and to continuously improve model accuracy. In addition, more environmental monitoring studies that aim at the quantification of ENM release and inadvertent transfer, particularly triggered by waste treatment

  2. Environmental fate of roxarsone in poultry litter. I. Degradation of roxarsone during composting

    Science.gov (United States)

    Garbarino, J.R.; Bednar, A.J.; Rutherford, D.W.; Beyer, R.S.; Wershaw, R. L.

    2003-01-01

    Roxarsone, 3-nitro-4-hydroxyphenylarsonic acid, is an organoarsenic compound that is used extensively in the feed of broiler poultryto control coccidial intestinal parasites, improve feed efficiency, and promote rapid growth. Nearly all the roxarsone in the feed is excreted unchanged in the manure. Poultry litter composed of the manure and bedding material has a high nutrient content and is used routinely as a fertilizer on cropland and pasture. Investigations were conducted to determine the fate of poultrylitter roxarsone in the environment. Experiments indicated that roxarsone was stable in fresh dried litter; the primary arsenic species extracted with water from dried litter was roxarsone. However, when water was added to litter at about 50 wt % and the mixture was allowed to compost at 40oC, the speciation of arsenic shifted from roxarsone to primarily arsenate in about 30 days. Increasing the amount of water increased the rate of degradation. Experiments also suggested that the degradation process most likely was biotic in nature. The rate of degradation was directly proportional to the incubation temperature; heat sterilization eliminated the degradation. Biotic degradation also was supported by results from enterobacteriaceae growth media that were inoculated with litter slurry to enhance the biotic processes and to reduce the concomitant abiotic effects from the complex litter solution. Samples collected from a variety of litter windrows in Arkansas, Oklahoma, and Maryland also showed that roxarsone originally present had been converted to arsenate.

  3. Phytoaccumulation of antimicrobials from biosolids: impacts on environmental fate and relevance to human exposure.

    Science.gov (United States)

    Aryal, Niroj; Reinhold, Dawn M

    2011-11-01

    Triclocarban and triclosan, two antimicrobials widely used in consumer products, can adversely affect ecosystems and potentially impact human health. The application of biosolids to agricultural fields introduces triclocarban and triclosan to soil and water resources. This research examined the phytoaccumulation of antimicrobials, effects of plant growth on migration of antimicrobials to water resources, and relevance of phytoaccumulation in human exposure to antimicrobials. Pumpkin, zucchini, and switch grass were grown in soil columns to which biosolids were applied. Leachate from soil columns was assessed every other week for triclocarban and triclosan. At the end of the trial, concentrations of triclocarban and triclosan were determined for soil, roots, stems, and leaves. Results indicated that plants can reduce leaching of antimicrobials to water resources. Pumpkin and zucchini growth significantly reduced soil concentrations of triclosan to less than 0.001 mg/kg, while zucchini significantly reduced soil concentrations of triclocarban to 0.04 mg/kg. Pumpkin, zucchini, and switch grass accumulated triclocarban and triclosan in mg per kg (dry) concentrations. Potential human exposure to triclocarban from consumption of pumpkin or zucchini was substantially less than exposure from product use, but was greater than exposure from drinking water consumption. Consequently, research indicated that pumpkin and zucchini may beneficially impact the fate of antimicrobials in agricultural fields, while presenting minimal acute risk to human health. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Impact of surface coating and environmental conditions on the fate and transport of silver nanoparticles in the aquatic environment

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, Laura-Jayne A.; Valsami-Jones, Eugenia [School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Lead, Jamie R., E-mail: Jlead@mailbox.sc.edu [School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Center for Environmental Nanoscience and Risk (CENR), Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia 29208 (United States); Baalousha, Mohammed, E-mail: Mbaalous@mailbox.sc.edu [Center for Environmental Nanoscience and Risk (CENR), Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia 29208 (United States)

    2016-10-15

    The role of surface coating (polyvinylpyrrolidone (PVP) and citrate) and water chemistry on the fate and behavior of AgNPs in aquatic microcosms is reported in this study. The migration and transformation of the AgNPs was examined in low (ultrapure water-UPW) and high ionic strength (moderately hard water – MHW) preparations, and in the presence of modeled natural organic matter (NOM) of Suwannee River Fulvic Acid (SRFA). The migration and fate of the AgNPs in the microcosms was validated using a sedimentation-diffusion model and the aggregation behavior was monitored by UV–visible spectrometry (UV–vis). Dissolved and particulate Ag concentrations (% Ag) were analyzed by ultrafiltration methods. Imaging of the AgNPs was captured using transmission electron microscopy (TEM). Results indicate that PVP-coated AgNPs (PVP-AgNPs) remained stable for 28 days with similarly distributed concentrations of the PVP-AgNPs throughout the columns in each of the water conditions after approximately 96 h (4 days). The sedimentation-diffusion model confirmed PVP-AgNP stability in each condition, by showing diffusion dominated transport by using the original unaltered AgNP sizes to fit the parameters. In comparison, citrate AgNPs were largely unstable in the more complex water preparations (MHW). In MHW, aggregation dominated behavior followed by sedimentation/dissolution controlled transport was observed. The addition of SRFA to MHW resulted in small stabilizing effects, to the citrate coated AgNPs, producing smaller sized AgNPs (TEM) and mixed sedimentation and diffusion migration compared the studies absent of SRFA. The results suggest that surface coating and solution chemistry has a major impact on AgNP stability, furthermore the corresponding modeling will support the experimental understanding of the overall fate of AgNPs in the environment. - Highlights: • Aquatic microcosms were used to study the transport and behavior of AgNPs • Experiments were conducted in low

  5. Impact of surface coating and environmental conditions on the fate and transport of silver nanoparticles in the aquatic environment

    International Nuclear Information System (INIS)

    Ellis, Laura-Jayne A.; Valsami-Jones, Eugenia; Lead, Jamie R.; Baalousha, Mohammed

    2016-01-01

    The role of surface coating (polyvinylpyrrolidone (PVP) and citrate) and water chemistry on the fate and behavior of AgNPs in aquatic microcosms is reported in this study. The migration and transformation of the AgNPs was examined in low (ultrapure water-UPW) and high ionic strength (moderately hard water – MHW) preparations, and in the presence of modeled natural organic matter (NOM) of Suwannee River Fulvic Acid (SRFA). The migration and fate of the AgNPs in the microcosms was validated using a sedimentation-diffusion model and the aggregation behavior was monitored by UV–visible spectrometry (UV–vis). Dissolved and particulate Ag concentrations (% Ag) were analyzed by ultrafiltration methods. Imaging of the AgNPs was captured using transmission electron microscopy (TEM). Results indicate that PVP-coated AgNPs (PVP-AgNPs) remained stable for 28 days with similarly distributed concentrations of the PVP-AgNPs throughout the columns in each of the water conditions after approximately 96 h (4 days). The sedimentation-diffusion model confirmed PVP-AgNP stability in each condition, by showing diffusion dominated transport by using the original unaltered AgNP sizes to fit the parameters. In comparison, citrate AgNPs were largely unstable in the more complex water preparations (MHW). In MHW, aggregation dominated behavior followed by sedimentation/dissolution controlled transport was observed. The addition of SRFA to MHW resulted in small stabilizing effects, to the citrate coated AgNPs, producing smaller sized AgNPs (TEM) and mixed sedimentation and diffusion migration compared the studies absent of SRFA. The results suggest that surface coating and solution chemistry has a major impact on AgNP stability, furthermore the corresponding modeling will support the experimental understanding of the overall fate of AgNPs in the environment. - Highlights: • Aquatic microcosms were used to study the transport and behavior of AgNPs • Experiments were conducted in low

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

    Science.gov (United States)

    Hansen, K. M.; Christensen, J. H.; Geels, C.; Silver, J. D.; Brandt, J.

    2015-06-01

    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 Arctic and their environmental fate within the Arctic. Three sets of simulations were performed, one with present day emissions and initial environmental concentrations from a 20-year spin-up simulation, one with present day emissions and with initial environmental concentrations set to zero and one without emissions but with initial environmental concentrations from the 20-year spin-up simulation. Each set of simulations consisted of two 10-year time slices representing the present (1990-2000) and future (2090-2100) climate conditions. DEHM was driven using meteorological input from the global circulation model, ECHAM/MPI-OM, simulating the SRES (Special Report on Emissions Scenarios) A1B climate scenario. Under the applied climate and emission scenarios, the total mass of all compounds was predicted to be up to 55 % lower across the Northern Hemisphere at the end of the 2090s than in the 1990s. The mass of HCHs within the Arctic was predicted to be up to 38 % higher, whereas the change in mass of the PCBs was predicted to range from 38 % 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 depends on the physical-chemical properties of the compounds. Previous model

  7. 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.

  8. Transformation of triphenyltin by Eubacteria: Fate and effects in environmental system

    Digital Repository Service at National Institute of Oceanography (India)

    Jadhav, S.

    and organisms. Knowledge about the environmental concentrations of any chemical compound is required to understand its effects on the system. Presence of such compounds in the environment is a serious threat and danger for human health and aquatic organisms...

  9. Macro-economic environmental models

    International Nuclear Information System (INIS)

    Wier, M.

    1993-01-01

    In the present report, an introduction to macro-economic environmental models is given. The role of the models as a tool for policy analysis is discussed. Future applications, as well as the limitations given by the data, are brought into focus. The economic-ecological system is described. A set of guidelines for implementation of the system in a traditional economic macro-model is proposed. The characteristics of empirical national and international environmental macro-economic models so far are highlighted. Special attention is paid to main economic causalities and their consequences for the environmental policy recommendations sat by the models. (au) (41 refs.)

  10. Environmental fate of depleted uranium at three sites contaminated during the balkan conflict

    International Nuclear Information System (INIS)

    Radenkovic, M.; Joksic, J.; Todorovic, D.; Kovacevic, M.

    2006-01-01

    A study on depleted uranium fate in the sites contaminated during the 1999 war conflict in Serbia was conducted in phases until the clean up activities were completed. The ammunition remains found at the locations in the surface soil were collected in the first phase during the radiation survey of the affected areas. The most of depleted uranium penetrators left buried deep into the ground exposed to the weathering and corrosion processes. The contamination level in the air, water, soil and bio -indicators was controlled all the time by routine gamma and alpha spectrometry measurements. Depleted uranium migration was studied through the soil profile surrounding the penetrator during the 2001 at the Bratoselce location showing the contamination level fall to the 1% of its value at approximately 15 cm distance to the source. The samples taken from the soil layers at different distances in the profile are subjected to a modified Tessiers five-step sequential extraction procedure. The uranium and heavy metals contents were determined in the obtained fractions. Results have specified carbonates and iron hydrous-oxides as the most probable substrates for uranium physical/chemical associations formed in the soil for the time elapsed. A very strong dependence of substrate onto contamination level was found. The correlation of uranium and other heavy metals was obtained. The 234 U/ 238 U and 235 U/ 238 U ratios are determined in extracts by alpha spectrometry after appropriate radiochemical separation procedure and thin alpha sources electroplating. The analysis has shown the share of depleted in total uranium content in exchangeable, carbonate, hydrous or crystalline iron/manganese, organic and residue phases indicating the bioavailability of depleted uranium present in the soil. The results are discussed related to detailed geochemical analysis of the particular soil type common for this region. Depleted uranium content in soil samples taken at the locations after the

  11. US Geological Survey research on the environmental fate of uranium mining and milling wastes

    International Nuclear Information System (INIS)

    Landa, E.R.; Gray, J.R.

    1995-01-01

    Studies by the US Geological Survey (USGS) of uranium mill tailings (UMT) have focused on characterizing the forms in which radionuclides are retained and identifying factors influencing the release of radionuclides to air and water. Selective extraction studies and studies of radionuclide sorption by and reaching from components of UMT showed alkaline earth sulfate and hydrous ferric oxides to be important hosts of radium-226 ( 226 Ra) in UMT. Extrapolating from studies of barite dissolution in anerobic lake sediments, the leaching of 226 Ra from UMT by sulfate-reducing bacteria was investigated; a marked increase in 226 Ra release to aqueous solution as compared to sterile controls was demonstrated. A similar action of iron(III)-reducing bacteria was later shown. Ion exchangers such as clay minerals can also promote the dissolution of host-phase minerals and thereby influence the fate of radionuclides such as 226 Ra. Radon release studies examined particle size and ore composition as variables. Aggregation of UMT particles was shown to mask the higher emanating fraction of finer particles. Studies of various ores and ore components showed that UMT cannot be assumed to have the same radon-release characteristics as their precursor ores, nor can 226 Ra retained by various substrates be assumed to emanate the same fraction of radon. Over the last decade, USGS research directed at offsite mobility of radionuclides form uranium mining and milling processes has focused on six areas: the Midnite Mine in Washington; Ralston Creek and Reservoir, Colorado; sites near Canon City, Colorado; the Monument Valley District of Arizona and Utah; the Cameron District of Arizona; and the Puerco River basin of Arizona and New Mexico. 48 refs., 6 figs., 4 tabs

  12. Characterising performance of environmental models

    NARCIS (Netherlands)

    Bennett, N.D.; Croke, B.F.W.; Guariso, G.; Guillaume, J.H.A.; Hamilton, S.H.; Jakeman, A.J.; Marsili-Libelli, S.; Newham, L.T.H.; Norton, J.; Perrin, C.; Pierce, S.; Robson, B.; Seppelt, R.; Voinov, A.; Fath, B.D.; Andreassian, V.

    2013-01-01

    In order to use environmental models effectively for management and decision-making, it is vital to establish an appropriate level of confidence in their performance. This paper reviews techniques available across various fields for characterising the performance of environmental models with focus

  13. Validation of an orimulsion spill fates model using observations from field test spills

    International Nuclear Information System (INIS)

    French, D. P.; Rines, H.; Masciangioli, P.

    1997-01-01

    The SIMAP Spill Impact Model system was developed to simulate fates and effects of spilled oil and other fuels in 3-D and time. Orimulsion is a Venezuelan product consisting of 70 per cent bitumen and 30 per cent water which has been shipped to many parts of the world for some time without an accidental spill into coastal or marine waters. In July 1966 two intentional spills of Orimulsion into Carribean waters were made and sampled in detail in order to verify the SIMAP model. Data on physical dispersion was collected at the same time. Data collected in the field was compared with model simulations. Results confirmed SIMAP's ability to predict the increasing dispersion and shearing of the bitumen plume as wind speed increases, as well as the actual field distribution of subsurface and surface bitumen. 17 refs., 7 tabs., 26 figs

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

    International Nuclear Information System (INIS)

    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

  15. Environmental Satellite Models for a Macroeconomic Model

    International Nuclear Information System (INIS)

    Moeller, F.; Grinderslev, D.; Werner, M.

    2003-01-01

    To support national environmental policy, it is desirable to forecast and analyse environmental indicators consistently with economic variables. However, environmental indicators are physical measures linked to physical activities that are not specified in economic models. One way to deal with this is to develop environmental satellite models linked to economic models. The system of models presented gives a frame of reference where emissions of greenhouse gases, acid gases, and leaching of nutrients to the aquatic environment are analysed in line with - and consistently with - macroeconomic variables. This paper gives an overview of the data and the satellite models. Finally, the results of applying the model system to calculate the impacts on emissions and the economy are reviewed in a few illustrative examples. The models have been developed for Denmark; however, most of the environmental data used are from the CORINAIR system implemented in numerous countries

  16. Emissions and fate of brominated flame retardants in the indoor environment: A critical review of modelling approaches

    Energy Technology Data Exchange (ETDEWEB)

    Liagkouridis, Ioannis, E-mail: ioannis.liagkouridis@ivl.se [IVL Swedish Environmental Research Institute, P.O. Box 21060, SE 100 31 Stockholm (Sweden); ITM Department of Applied Environmental Science, Stockholm University, SE 106 91 Stockholm (Sweden); Cousins, Ian T. [ITM Department of Applied Environmental Science, Stockholm University, SE 106 91 Stockholm (Sweden); Cousins, Anna Palm [IVL Swedish Environmental Research Institute, P.O. Box 21060, SE 100 31 Stockholm (Sweden)

    2014-09-01

    This review explores the existing understanding and the available approaches to estimating the emissions and fate of semi-volatile organic compounds (SVOCs) and in particular focuses on the brominated flame retardants (BFRs). Volatilisation, an important emission mechanism for the more volatile compounds can be well described using current emission models. More research is needed, however, to better characterise alternative release mechanisms such as direct material–particle partitioning and material abrasion. These two particle-mediated emissions are likely to result in an increased chemical release from the source than can be accounted for by volatilisation, especially for low volatile compounds, and emission models need to be updated in order to account for these. Air–surface partitioning is an important fate process for SVOCs such as BFRs however it is still not well characterised indoors. In addition, the assumption of an instantaneous air–particle equilibrium adopted by current indoor fate models might not be valid for high-molecular weight, strongly sorbing compounds. A better description of indoor particle dynamics is required to assess the effect of particle-associated transport as this will control the fate of low volatile BFRs. We suggest further research steps that will improve modelling precision and increase our understanding of the factors that govern the indoor fate of a wide range of SVOCs. It is also considered that the appropriateness of the selected model for a given study relies on the individual characteristics of the study environment and scope of the study. - Highlights: • Current emission models likely underestimate the release of low volatile BFRs from products. • Material abrasion and direct material–dust partitioning are important, yet understudied emission mechanisms. • Indoor surfaces can be significant sinks, but the mechanism is poorly understood. • Indoor fate of low volatile BFRs is strongly associated with particle

  17. The influence of global climate change on the environmental fate of persistent organic pollutants: A review with emphasis on the Northern Hemisphere and the Arctic as a receptor

    Science.gov (United States)

    Ma, Jianmin; Hung, Hayley; Macdonald, Robie W.

    2016-11-01

    Following worldwide bans and restrictions on the use of many persistent organic pollutants (POPs) from the late 1970s, their regional and global distributions have become governed increasingly by phase partitioning between environmental reservoirs, such as air, water, soil, vegetation and ice, where POPs accumulated during the original applications. Presently, further transport occurs within the atmospheric and aquatic reservoirs. Increasing temperatures provide thermodynamic forcing to drive these chemicals out of reservoirs, like soil, vegetation, water and ice, and into the atmosphere where they can be transported rapidly by winds and then recycled among environmental media to reach locations where lower temperatures prevail (e.g., polar regions and high elevations). Global climate change, widely considered as global warming, is also manifested by changes in hydrological systems and in the cryosphere; with the latter now exhibiting widespread loss of ice cover on the Arctic Ocean and thawing of permafrost. All of these changes alter the cycling and fate of POPs. There is abundant evidence from observations and modeling showing that climate variation has an effect on POPs levels in biotic and abiotic environments. This article reviews recent progress in research on the effects of climate change on POPs with the intention of promoting awareness of the importance of interactions between climate and POPs in the geophysical and ecological systems.

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

    Science.gov (United States)

    Hansen, K. M.; Christensen, J. H.; Geels, C.; Silver, J. D.; Brandt, J.

    2015-03-01

    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 a changed climate on

  19. 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 ...

  20. 40 CFR 158.2174 - Experimental use permit microbial pesticides nontarget organisms and environmental fate data...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Experimental use permit microbial... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS DATA REQUIREMENTS... controls the target insect pest by a mechanism of infectivity; i.e., may create an epizootic condition in...

  1. Modelling the fate of sulphur-35 in crops. 1. Calibration data

    International Nuclear Information System (INIS)

    Collins, Chris; Cunningham, Nathan

    2005-01-01

    Gas-cooled nuclear power plants in the UK release sulphur-35 during their routine operation. The gas is in the form of COS which can be readily assimilated by vegetation. It is therefore necessary to be able to model the uptake of such releases in order to quantify any potential contamination of the food chain. To develop such models experimental data are required. A series of experiments was undertaken to determine the rate of deposition, the partition and subsequent loss of sulphur-35 in crops exposed to CO 35 S. The mass normalised deposition rate was similar for the range of crops tested, while the partition of the 35 S paralleled the growth of crop components. There was no significant loss of radioactivity other than that expected from radioactive decay. - The deposition, fate and loss of 35 S in crops were quantified following exposure to COS

  2. Metabolic fate of 14-C-fenitrothion in a rice field model ecosystem

    International Nuclear Information System (INIS)

    Nashriyah binti Mat; Nambu, K.; Miyashita, T.; Sakata, S.; Ohshima, M.

    1991-01-01

    Pesticide fenitrothion (Sumithion sup R)is widely used to control rice stem borer and other pests. Its metabolic fate and degradation was studied using the sup 14 C-ring labelled fenitrothion in a model ecosystem consisting of Takarazuka paddy field soil, rice plant (Oryza sativa var. nihonbare), carp fish (Cyprinus carpio L.) and dechlorinated water. Radioactive fenitrothion was applied at a normal rate as used by Japanese farmers and samples of rice plant, fish soil and water were analysed after ten days of application. Fenitrothion was readily metabolized in rice plant and fish and also readily degraded to a number of metabolites in water and flooded soil. Most of the radioactivity applied was found in the soil component of the ecosystem. A trace amount of fenitrooxon, the activated metabolite of fenitrothion was detected only in soil and water. A possible metabolic pathway of fenitrothion in the rice model ecosystem was proposed

  3. OPERA: A free and open source QSAR tool for predicting physicochemical properties and environmental fate endpoints

    Science.gov (United States)

    Collecting the chemical structures and data for necessary QSAR modeling is facilitated by available public databases and open data. However, QSAR model performance is dependent on the quality of data and modeling methodology used. This study developed robust QSAR models for physi...

  4. A reactive transport model for mercury fate in soil--application to different anthropogenic pollution sources.

    Science.gov (United States)

    Leterme, Bertrand; Blanc, Philippe; Jacques, Diederik

    2014-11-01

    Soil systems are a common receptor of anthropogenic mercury (Hg) contamination. Soils play an important role in the containment or dispersion of pollution to surface water, groundwater or the atmosphere. A one-dimensional model for simulating Hg fate and transport for variably saturated and transient flow conditions is presented. The model is developed using the HP1 code, which couples HYDRUS-1D for the water flow and solute transport to PHREEQC for geochemical reactions. The main processes included are Hg aqueous speciation and complexation, sorption to soil organic matter, dissolution of cinnabar and liquid Hg, and Hg reduction and volatilization. Processes such as atmospheric wet and dry deposition, vegetation litter fall and uptake are neglected because they are less relevant in the case of high Hg concentrations resulting from anthropogenic activities. A test case is presented, assuming a hypothetical sandy soil profile and a simulation time frame of 50 years of daily atmospheric inputs. Mercury fate and transport are simulated for three different sources of Hg (cinnabar, residual liquid mercury or aqueous mercuric chloride), as well as for combinations of these sources. Results are presented and discussed with focus on Hg volatilization to the atmosphere, Hg leaching at the bottom of the soil profile and the remaining Hg in or below the initially contaminated soil layer. In the test case, Hg volatilization was negligible because the reduction of Hg(2+) to Hg(0) was inhibited by the low concentration of dissolved Hg. Hg leaching was mainly caused by complexation of Hg(2+) with thiol groups of dissolved organic matter, because in the geochemical model used, this reaction only had a higher equilibrium constant than the sorption reactions. Immobilization of Hg in the initially polluted horizon was enhanced by Hg(2+) sorption onto humic and fulvic acids (which are more abundant than thiols). Potential benefits of the model for risk management and remediation of

  5. Chemical Transformation System: Cloud Based Cheminformatic Services to Support Integrated Environmental Modeling

    Science.gov (United States)

    Integrated Environmental Modeling (IEM) systems that account for the fate/transport of organics frequently require physicochemical properties as well as transformation products. A myriad of chemical property databases exist but these can be difficult to access and often do not co...

  6. Chemical Transformation System: Cloud Based Cheminformatic Services to Support Integrated Environmental Modeling (proceedings)

    Science.gov (United States)

    Integrated Environmental Modeling (IEM) systems that account for the fate/transport of organics frequently require physicochemical properties as well as transformation products. A myriad of chemical property databases exist but these can be difficult to access and often do not co...

  7. Regional Persistent Organic Pollutants' Environmental Impact Assessment and Control Model

    Directory of Open Access Journals (Sweden)

    Jurgis Staniskis

    2008-10-01

    Full Text Available The sources of formation, environmental distribution and fate of persistent organic pollutants (POPs are increasingly seen as topics to be addressed and solved at the global scale. Therefore, there are already two international agreements concerning persistent organic pollutants: the Protocol of 1998 to the 1979 Convention on the Long-Range Transboundary Air Pollution on Persistent Organic Pollutants (Aarhus Protocol; and the Stockholm Convention on Persistent Organic Pollutants. For the assessment of environmental pollution of POPs, for the risk assessment, for the evaluation of new pollutants as potential candidates to be included in the POPs list of the Stokholmo or/and Aarhus Protocol, a set of different models are developed or under development. Multimedia models help describe and understand environmental processes leading to global contamination through POPs and actual risk to the environment and human health. However, there is a lack of the tools based on a systematic and integrated approach to POPs management difficulties in the region.

  8. Environmental fate and behaviour of the biocontrol agent Bacillus amyloliquefaciens CPA-8 after preharvest application to stone fruit.

    Science.gov (United States)

    Vilanova, Laura; Teixidó, Neus; Usall, Josep; Balsells-Llauradó, Marta; Gotor-Vila, Amparo; Torres, Rosario

    2018-02-01

    Bacillus amyloliquefaciens strain CPA-8 has been described as an effective biocontrol agent to control brown rot in stone fruit for both preharvest and postharvest applications. However, no information about the environmental fate and behaviour of this strain under field conditions is available. The dispersion of the CPA-8 application was evaluated using water-sensitive papers, and complete coverage was observed on the leaves of treated trees, while treatment. On non-treated trees, CPA-8 was detected on leaves until 180 days after treatment, and on weeds, the CPA-8 population was dependent on the distance from the treated trees. A high persistence of CPA-8 was detected on inert materials, such as clothes and gloves worn by handlers and plastic harvesting boxes. More than 99% of the samples with a CPA-8 phenotype were confirmed as CPA-8 using polymerase chain reaction (PCR). This work demonstrated a good distribution, persistence and adaptation of the CPA-8 strain to field and postharvest conditions. Monitoring of dispersion and persistence is an excellent tool to determine the time of application and provides valuable information for registering issues. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  9. Role of environmental factors and microorganisms in determining the fate of polycyclic aromatic hydrocarbons in the marine environment

    Science.gov (United States)

    Duran, Robert; Cravo-Laureau, Cristiana

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are widespread in marine ecosystems and originate from natural sources and anthropogenic activities. PAHs enter the marine environment in two main ways, corresponding to chronic pollution or acute pollution by oil spills. The global PAH fluxes in marine environments are controlled by the microbial degradation and the biological pump, which plays a role in particle settling and in sequestration through bioaccumulation. Due to their low water solubility and hydrophobic nature, PAHs tightly adhere to sediments leading to accumulation in coastal and deep sediments. Microbial assemblages play an important role in determining the fate of PAHs in water and sediments, supporting the functioning of biogeochemical cycles and the microbial loop. This review summarises the knowledge recently acquired in terms of both chronic and acute PAH pollution. The importance of the microbial ecology in PAH-polluted marine ecosystems is highlighted as well as the importance of gaining further in-depth knowledge of the environmental services provided by microorganisms. PMID:28201512

  10. Sorption of lipophilic organic compunds to wood and implications for their environmental fate

    DEFF Research Database (Denmark)

    Trapp, Stefan; Miglioranza, S.B.; Mosbæk, Hans

    2001-01-01

    The sorption from water to wood (KWood) of 10 organic chemicals (logKOW, 1.48-6.20) was experimentally determined for oak (Quercus robur) and basket willow (Salix viminalis). Linear regression yielded log KWood ) -0.27 (( 0.25) + 0.632 (( 0.063)log KOW for oak (r ) 0.90, n ) 27) and log KWood ) -...... time. If metabolism inside the stem occurs, wood can serve as a “safe sink” for environmental chemicals. This might be of use in phytoremediation....

  11. Fate, behaviour and toxicity of engineered nanomaterials in the environmental systems

    CSIR Research Space (South Africa)

    Musee, N

    2012-04-01

    Full Text Available ? Environmental risks of ENMs to biological organisms in the environment MUST satisfy two conditions: Hazard & Exposure ? Hazard (toxic effect): due to nano/bio interface ?interactions of ENMs with: Biomolecules, cell membranes, the cellular interior...., Langmuir, 2011, Effect of surface coating A: Unmodified AgNPs B: Modified SDS AgNPs Steric effects due to EDL, increased zeta potential and enhanced AgNPs stability DLS size measurements B: Modified Tween 80 AgNPs A: Unmodified AgNPs A: 0 ?L...

  12. Fate of linear alkylbenzenes and benzothiazoles of anthropogenic origin and their potential as environmental molecular markers in the Pearl River Delta, South China

    International Nuclear Information System (INIS)

    Ni Honggang; Shen Rulang; Zeng Hui; Zeng, Eddy Y.

    2009-01-01

    The mass emissions of linear alkylbenzenes (LABs), benzothiazole (BT), and 2-[4-morpholinyl]benzothiazole (24MoBT) from anthropogenic activities within one year were estimated according to the population and the number of automobiles in the Pearl River Delta (PRD), South China. Based on the estimation, the distribution of these compounds among various environmental media was simulated with a mass balance box model established in the present study. The results showed that 79% of LABs generated in the PRD was stored in sediment while only 1.3% of LABs was presumably transported to the adjacent South China Sea (SCS). On the contrary, 47% of BT and 77% of 24MoBT generated in the region were carried with riverine runoff to the coastal ocean. The results from the present study suggest that hydrophobic compounds tend to stay in the watershed of the PRD, whereas hydrophilic ones mainly outflow to the coastal ocean. - A simple mass balance box model examines the fate of linear alkylbenzenes and benzothiazoles in the Pearl River Delta, South China.

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

    International Nuclear Information System (INIS)

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

    2011-01-01

    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.

  14. Risk assessment framework of fate and transport models applied to hazardous waste sites

    International Nuclear Information System (INIS)

    Hwang, S.T.

    1993-06-01

    Risk assessment is an increasingly important part of the decision-making process in the cleanup of hazardous waste sites. Despite guidelines from regulatory agencies and considerable research efforts to reduce uncertainties in risk assessments, there are still many issues unanswered. This paper presents new research results pertaining to fate and transport models, which will be useful in estimating exposure concentrations and will help reduce uncertainties in risk assessment. These developments include an approach for (1) estimating the degree of emissions and concentration levels of volatile pollutants during the use of contaminated water, (2) absorption of organic chemicals in the soil matrix through the skin, and (3) steady state, near-field, contaminant concentrations in the aquifer within a waste boundary

  15. Fate of acetone in an outdoor model stream in southern Mississippi, U.S.A.

    Science.gov (United States)

    Rathbun, R.E.; Stephens, D.W.; Shultz, D.J.; Tai, D.Y.

    1988-01-01

    The fate of acetone in water was investigated in an outdoor model stream located in southern Mississippi, U.S.A. Acetone was injected continuously for 32 days resulting in small milligram-perliter concentrations in the stream. Rhodamine-WT dye was injected at the beginning and at the end of the study to determine the time-of-travel and dispersion characteristics of the stream. A 12-h injection of t-butyl alcohol (TBA) was used to determine the volatilization characteristics of the stream. Volatilization controlled the acetone concentration in the stream. Significant bacterial degradation of acetone did not occur, contrary to expectations based on previous laboratory studies. Attempts to induce degradation of the acetone by injecting glucose and a nutrient solution containing bacteria acclimated to acetone were unsuccessful. Possible explanations for the lack of bacterial degradation included a nitrate limitation and a limited residence time in the stream system. ?? 1988.

  16. BETR-World: a geographically explicit model of chemical fate: application to transport of α-HCH to the Arctic

    International Nuclear Information System (INIS)

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

    2004-01-01

    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 α-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 α-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 α-HCH to the Arctic, showing Europe and the Orient are key sources

  17. Environmental fate and quantitative analysis of oilsands naphthenic acids : a review

    Energy Technology Data Exchange (ETDEWEB)

    McMartin, D. [Regina Univ., SK (Canada). Faculty of Engineering; Peru, K.M.; Headley, J. [Environment Canada, Saskatoon, SK (Canada). National Water Research Inst.

    2006-07-01

    Naphthenic acids (NA) are toxic to aquatic species and mammals. Significant concentrations of NA are found in oil sands tailings ponds. This presentation reviewed some of the analytical tools used by industry and environmentalists to remediate NA. Environmental persistence results were presented, as well as detailed information regarding the origin of NA in tailings ponds. Chemistry and toxicological considerations were examined, and current analytical methods for aquatic sampling were reviewed. Issues concerning photodegradation and phytoremediation were discussed. Details of the environmental effects of NA exposure were presented. Studies investigating the microbial populations required to degrade NA in water were discussed, as well as recent research investigating the phytoremediation of wetlands exposed to NA. It was noted that research is currently being conducted to optimize algae culture for use in phytoremediation methods. However, many of the components of NA are resistant to the biodegradation, photodegradation and phytoremediation methods currently used. It was concluded that further research is needed to complete mass balance studies in riverine systems and to evaluate the cellular level toxicity of NA in plants. refs., tabs., figs.

  18. Photodegradation of antibiotics under simulated solar radiation: implications for their environmental fate.

    Science.gov (United States)

    Batchu, Sudha Rani; Panditi, Venkata R; O'Shea, Kevin E; Gardinali, Piero R

    2014-02-01

    Roxithromycin, erythromycin, ciprofloxacin and sulfamethoxazole are frequently detected antibiotics in environmental waters. Direct and indirect photolysis of these problematic antibiotics were investigated in pure and natural waters (fresh and salt water) under irradiation of different light sources. Fundamental photolysis parameters such as molar absorption coefficient, quantum yield and first order rate constants are reported and discussed. The antibiotics are degraded fastest under ultraviolet 254 nm, followed by 350 nm and simulated solar radiation. The composition of the matrix (pH, dissolved organic content, chloride ion concentration) played a significant role in the observed photodegradation. Under simulated solar radiation, ciprofloxacin and sulfamethoxazole degrade relatively quickly with half-lives of 0.5 and 1.5h, respectively. However, roxithromycin and erythromycin, macrolides are persistent (half-life: 2.4-10 days) under solar simulation. The transformation products (15) of the targeted antibiotics produced under irradiation experiments were identified using high resolution mass spectrometry and degradation pathways were proposed. © 2013.

  19. Development of Cortical GABAergic Neurons: Interplay of progenitor diversity and environmental factors on fate specification

    Directory of Open Access Journals (Sweden)

    Juliana Alves Brandão

    2015-04-01

    Full Text Available Cortical GABAergic interneurons constitute an extremely diverse population of cells organized in a well-defined topology of precisely interconnected cells. They play a crucial role regulating inhibitory-excitatory balance in brain circuits, gating sensory perception and regulating spike timing to brain oscillations during distinct behaviors. Dysfunctions in the establishment of proper inhibitory circuits have been associated to several brain disorders such as autism, epilepsy and schizophrenia. In the rodent adult cortex, inhibitory neurons are generated during the second gestational week from distinct progenitor lineages located in restricted domains of the ventral telencephalon. However, only recently, studies have revealed some of the mechanisms generating the heterogeneity of neuronal subtypes and their modes of integration in brain networks. Here we will discuss some the events involved in the production of cortical GABAergic neuron diversity with focus on the interaction between intrinsically driven genetic programs and environmental signals during development.

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

    Science.gov (United States)

    Natural waters provide habitats for various groups of fecal indicator organisms (FIOs) and pathogenic microorganisms originating from animal manures and animal waste. A number of watershed modeling works have been carried out to have a better understanding to the fate and transport of fecal indicato...

  1. Fate of nano- and microplastic in freshwater systems: A modeling study

    NARCIS (Netherlands)

    Besseling, Ellen; Quik, Joris T.K.; Sun, Muzhi; Koelmans, Bart

    2017-01-01

    Riverine transport to the marine environment is an important pathway for microplastic. However, information on fate and transport of nano- and microplastic in freshwater systems is lacking. Here we present scenario studies on the fate and transport of nano-to millimetre sized spherical particles

  2. Application of SELECT and SWAT models to simulate source load, fate, and transport of fecal bacteria in watersheds.

    Science.gov (United States)

    Ranatunga, T.

    2017-12-01

    Modeling of fate and transport of fecal bacteria in a watershed is a processed based approach that considers releases from manure, point sources, and septic systems. Overland transport with water and sediments, infiltration into soils, transport in the vadose zone and groundwater, die-off and growth processes, and in-stream transport are considered as the other major processes in bacteria simulation. This presentation will discuss a simulation of fecal indicator bacteria source loading and in-stream conditions of a non-tidal watershed (Cedar Bayou Watershed) in South Central Texas using two models; Spatially Explicit Load Enrichment Calculation Tool (SELECT) and Soil and Water Assessment Tool (SWAT). Furthermore, it will discuss a probable approach of bacteria source load reduction in order to meet the water quality standards in the streams. The selected watershed is listed as having levels of fecal indicator bacteria that posed a risk for contact recreation and wading by the Texas Commission of Environmental Quality (TCEQ). The SELECT modeling approach was used in estimating the bacteria source loading from land categories. Major bacteria sources considered were, failing septic systems, discharges from wastewater treatment facilities, excreta from livestock (Cattle, Horses, Sheep and Goat), excreta from Wildlife (Feral Hogs, and Deer), Pet waste (mainly from Dogs), and runoff from urban surfaces. The estimated source loads from SELECT model were input to the SWAT model, and simulate the bacteria transport through the land and in-stream. The calibrated SWAT model was then used to estimate the indicator bacteria in-stream concentrations for future years based on regional land use, population and household forecast (up to 2040). Based on the reductions required to meet the water quality standards in-stream, the corresponding required source load reductions were estimated.

  3. A modified QWASI model for fate and transport modeling of mercury between the water-ice-sediment in Lake Ulansuhai.

    Science.gov (United States)

    Liu, Yu; Li, Changyou; Anderson, Bruce; Zhang, Sheng; Shi, Xiaohong; Zhao, Shengnan

    2017-06-01

    Mercury contamination from industrial and agricultural drainage into lakes and rivers is a growing concern in Northern China. Lake Ulansuhai, located in Hetao irrigation district in Inner Mongolia, is the only sink for the all industrial and agricultural drainage and sole outlet for this district to the Yellow River, which is one of the main source of drinking water for the numerous cities and towns downstream. Because Ulansuahi is ice-covered during winter, the QWASI model was modified by adding an ice equation to get a more accurate understanding of the fate and transport of mercury within the lake. Both laboratory and field tests were carried out during the ice growth period. The aquivalence and mass balance approaches were used to develop the modified QWASI + ice model. The margins of error between the modelled and the measured average concentrations of Hg in ice, water, and sediment were 30%, 26.2%, and 19.8% respectively. These results suggest that the new QWASI + ice model could be used to more accurately represent the fate and transport of mercury in the seasonally ice-covered lakes, during the ice growth period. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Fate of pollutants

    International Nuclear Information System (INIS)

    Chapta, S.C.; Boyer, J.M.

    1990-01-01

    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

  5. Environmentally Persistent Free Radical (EPFRs) - Ambient Air Particulates, Soils and Fate of Some Pollutants

    Science.gov (United States)

    Lomnicki, S. M.

    2017-12-01

    Environmentally Persistent Free Radicals (EPFRs) are relatively recently discovered species that are present on ambient air particulates. Their origin is typically associated with the combustion borne PM, where in the cool zone of the combustion process aromatic precursors react with the metal centers of particulates forming surface-organic complex with radical characteristics. EPFRs have been found to be sufficiently resistant to be emitted from the combustion sources and persist in the ambient air on particulates. Their inhalation has been associated with severe health effects, and potentially are one of the major agents contributing the epidemiological risks of PM exposure. Interestingly, EPFRs can be formed not only at the elevated temperatures but also in ambient conditions, where the contact of precursor molecules with transition metal (but not only) domains can result in adsorbate complexes. In fact, EPFRs have been detected in the contaminated soils, or during the oil spill incidents. It is very likely, that the interaction of some molecules released to the air can result in the formation of EPFRs on the ambient air particulates in atmospheric conditions. These species can be a natural degradation by-products that lead to the formation of oxygenated organics in ambient atmosphere.

  6. Occurrence, control and fate of contaminants of emerging concern in environmental compartments in Brazil.

    Science.gov (United States)

    Starling, Maria Clara V M; Amorim, Camila C; Leão, Mônica Maria D

    2018-04-22

    This is the first review to present data obtained in Brazil over the years regarding contaminants of emerging concern (CEC) and to contrast it with contamination in other countries. Data gathered indicated that caffeine, paracetamol, atenolol, ibuprofen, cephalexin and bisphenol A occur in the μg L -1 range in streams near urban areas. While endocrine disruptors are frequently detected in surface waters, highest concentrations account for 17α-ethynylestradiol and 17β-estradiol. Organochlorine pesticides are the most frequently found and persistent in sediments in agricultural regions. Moreover, in tropical agricultural fields, pesticide volatilization and its implications to ecosystem protection must be better investigated. The reality represented here for Brazil may be transposed to other developing countries due to similarities related to primitive basic sanitation infrastructure and economic and social contexts, which contribute to continuous environmental contamination by CEC. Municipal wastewater treatment facilities in Brazil, treat up to the secondary stage and lead to limited CEC removal. This is also true for other nations in Latin America, such as Argentina, Colombia and Mexico. Therefore, it is an urgent priority to improve sanitation infrastructure and, then, the implementation of tertiary treatment shall be imposed. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. A reactive transport model for mercury fate in contaminated soil--sensitivity analysis.

    Science.gov (United States)

    Leterme, Bertrand; Jacques, Diederik

    2015-11-01

    We present a sensitivity analysis of a reactive transport model of mercury (Hg) fate in contaminated soil systems. The one-dimensional model, presented in Leterme et al. (2014), couples water flow in variably saturated conditions with Hg physico-chemical reactions. The sensitivity of Hg leaching and volatilisation to parameter uncertainty is examined using the elementary effect method. A test case is built using a hypothetical 1-m depth sandy soil and a 50-year time series of daily precipitation and evapotranspiration. Hg anthropogenic contamination is simulated in the topsoil by separately considering three different sources: cinnabar, non-aqueous phase liquid and aqueous mercuric chloride. The model sensitivity to a set of 13 input parameters is assessed, using three different model outputs (volatilized Hg, leached Hg, Hg still present in the contaminated soil horizon). Results show that dissolved organic matter (DOM) concentration in soil solution and the binding constant to DOM thiol groups are critical parameters, as well as parameters related to Hg sorption to humic and fulvic acids in solid organic matter. Initial Hg concentration is also identified as a sensitive parameter. The sensitivity analysis also brings out non-monotonic model behaviour for certain parameters.

  8. A coupled reaction and transport model for assessing the injection, migration and fate of waste fluids

    International Nuclear Information System (INIS)

    Liu, X.; Ortoleva, P.

    1996-01-01

    The use of reaction-transport modeling for reservoir assessment and management in the context of deep well waste injection is evaluated. The study is based on CIRF.A (Chemical Interaction of Rock and Fluid), a fully coupled multiphase flow, contaminant transport, and fluid and mineral reaction model. Although SWIFT (Sandia Waste-Isolation Flow and Transport Model) is often the numerical model of choice, it can not account for chemical reactions involving rock, wastes, and formation fluids and their effects on contaminant transport, rock permeability and porosity, and the integrity of the reservoir and confining units. CIRF.A can simulate all these processes. Two field cases of waste injection were simulated by CIRF.A. Both observation data and simulation results show mineral precipitation in one case and rock dissolution in another case. Precipitation and dissolution change rock porosity and permeability, and hence the pattern of fluid migration. The model is shown to be invaluable in analyzing near borehole and reservoir-scale effects during waste injection and predicting the 10,000 year fate of the waste plume. The benefits of using underpressured compartments as waste repositories were also demonstrated by CIRF.A simulations

  9. Watershed-scale modeling on the fate and transport of polycyclic aromatic hydrocarbons (PAHs)

    International Nuclear Information System (INIS)

    Ligaray, Mayzonee; Baek, Sang Soo; Kwon, Hye-Ok; Choi, Sung-Deuk; Cho, Kyung Hwa

    2016-01-01

    PAHs are potentially carcinogenic substances that are persistent in the environment. Increasing concentrations of PAHs were observed due to rapid urbanization, thus; monitoring PAHs concentrations is necessary. However, it is expensive to conduct intensive monitoring activities of a large number of PAHs. This study addressed this issue by developing a multimedia model coupled with a hydrological model (i.e., Soil and Water Assessment Tool (SWAT)) for Taehwa River (TR) watershed in Ulsan, the industrial capital of South Korea. The hydrologic module of the SWAT was calibrated, and further used to simulate the fate and transport of PAHs in soil and waterbody. The model demonstrated that the temporal or seasonal variation of PAHs in soil and waterbody can be well reproduced. Meanwhile, the spatial distribution of PAHs showed that urban areas in TR watershed have the highest PAH loadings compared to rural areas. Sensitivity analyses of the PAH soil and PAH water parameters were also able to determine the critical processes in TR watershed: degradation, deposition, volatilization, and wash off mechanism. We hope that this model will be able to aid the stakeholders in: regulating PAH concentrations emitted by various sources; and also apply the model to other Persistent Organic Pollutants (POPs).

  10. Watershed-scale modeling on the fate and transport of polycyclic aromatic hydrocarbons (PAHs)

    Energy Technology Data Exchange (ETDEWEB)

    Ligaray, Mayzonee; Baek, Sang Soo [School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Ulsan 44919 (Korea, Republic of); Kwon, Hye-Ok [Disaster Scientific Investigation Division, National Disaster Management Research Institute, 365 Jongga-ro Jung-gu, Ulsan 44538 (Korea, Republic of); Choi, Sung-Deuk, E-mail: sdchoi@unist.ac.kr [School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Ulsan 44919 (Korea, Republic of); Cho, Kyung Hwa, E-mail: khcho@unist.ac.kr [School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Ulsan 44919 (Korea, Republic of)

    2016-12-15

    PAHs are potentially carcinogenic substances that are persistent in the environment. Increasing concentrations of PAHs were observed due to rapid urbanization, thus; monitoring PAHs concentrations is necessary. However, it is expensive to conduct intensive monitoring activities of a large number of PAHs. This study addressed this issue by developing a multimedia model coupled with a hydrological model (i.e., Soil and Water Assessment Tool (SWAT)) for Taehwa River (TR) watershed in Ulsan, the industrial capital of South Korea. The hydrologic module of the SWAT was calibrated, and further used to simulate the fate and transport of PAHs in soil and waterbody. The model demonstrated that the temporal or seasonal variation of PAHs in soil and waterbody can be well reproduced. Meanwhile, the spatial distribution of PAHs showed that urban areas in TR watershed have the highest PAH loadings compared to rural areas. Sensitivity analyses of the PAH soil and PAH water parameters were also able to determine the critical processes in TR watershed: degradation, deposition, volatilization, and wash off mechanism. We hope that this model will be able to aid the stakeholders in: regulating PAH concentrations emitted by various sources; and also apply the model to other Persistent Organic Pollutants (POPs).

  11. Integrated Environmental Assessment Modelling

    Energy Technology Data Exchange (ETDEWEB)

    Guardanz, R; Gimeno, B S; Bermejo, V; Elvira, S; Martin, F; Palacios, M; Rodriguez, E; Donaire, I [Ciemat, Madrid (Spain)

    2000-07-01

    This report describes the results of the Spanish participation in the project Coupling CORINAIR data to cost-effect emission reduction strategies based on critical threshold. (EU/LIFE97/ENV/FIN/336). The subproject has focused on three tasks. Develop tools to improve knowledge on the spatial and temporal details of emissions of air pollutants in Spain. Exploit existing experimental information on plant response to air pollutants in temperate ecosystem and Integrate these findings in a modelling framework that can asses with more accuracy the impact of air pollutants to temperate ecosystems. The results obtained during the execution of this project have significantly improved the models of the impact of alternative emission control strategies on ecosystems and crops in the Iberian Peninsula. (Author) 375 refs.

  12. Antimicrobial resistant Escherichia coli in the municipal wastewater system: effect of hospital effluent and environmental fate.

    Science.gov (United States)

    Harris, Suvi; Morris, Carol; Morris, Dearbhaile; Cormican, Martin; Cummins, Enda

    2014-01-15

    The prevalence of antimicrobial resistant (AMR) bacteria is increasing worldwide and remains a significant medical challenge which may lead to antimicrobial redundancy. The contribution of hospital effluent to the prevalence of resistance in wastewater treatment plant (WWTP) effluents is not fully understood. AMR bacteria contained in hospital effluent may be released into the aquatic and soil environments after WWTP processing. Hence, the objective of this study is to identify the extent hospital effluent contributes to contamination of these environments by comparing two WWTPs, one which receives hospital effluent and one which does not. AMR Escherichia coli were monitored in the two WWTPs. A model was developed using these monitored values to predict the effect of hospital effluent within a WWTP. The model predicted levels of AMR E. coli in the aquatic environment and potential bather exposure to AMR E. coli. The model results were highly variable. WWTP influent containing hospital effluent had a higher mean percentage of AMR E. coli; although, there appeared to be no within treatment plant effect on the prevalence of AMR E. coli. Examination of WWTP sludge showed a similar variation. There appeared to be no consistent effect from the presence of hospital effluent. The human exposure assessment model predicted swimmer intake of AMR E. coli between 6 and 193CFU/100ml sea water. It appears that hospital effluent is not the main contributing factor behind the development and persistence of AMR E. coli within WWTPs, although resistance may be too well-developed to identify an influence from hospital effluent. Mitigation needs to focus on the removal of already present resistant bacteria but for new or hospital specific antimicrobials focus needs to be on their limited release within effluents or separate treatment. © 2013.

  13. Modeling the transport and fate of radioactive noble gases in very dry desert alluvium: Realistic scenarios

    International Nuclear Information System (INIS)

    Lindstrom, F.T.; Cawlfield, D.E.; Donahue, M.E.; Emer, D.F.; Shott, G.J.

    1992-01-01

    US DOE Order 5820.2A (1988) requires that a performance assessment of all new and existing low-level radioactive waste management sites be made. An integral part of every performance assessment is the mathematical modeling of the transport and fate of noble gas radionuclides in the gas phase. Current in depth site characterization of the high desert alluvium in Area 5 of the Nevada Test Site (NTS) is showing that the alluvium is very very dry all the way to the water table (240 meters below land surface). The potential for radioactive noble gas (e.g. Rn-220 and Rn-222) transport to the atmosphere from shallow land burial of Thorium and Uranium waste is very high. Objectives of this modeling effort include: Construct a physics based sits specific noble gas transport model; Include induced advection due to barometric pressure changes at the atmospheric boundary layer (thin) - dry desert alluvium interface; User selected option for use of NOAA barometric pressure or a ''home brewed'' barometric pressure wave made up of up to 15 sinusoids and cosinusoids; Use the model to help make engineering decisions on the design of the burial pits and associated closure caps

  14. Pesticide Environmental Fate Research for the 21st Century: Building Bridges Between Laboratory and Field Studies at Varying Scales

    Science.gov (United States)

    Accurate determination of predicted environmental concentrations (PECs) is a continuing and often elusive goal of pesticide risk assessment. PECs are typically derived using simulation models that depend on laboratory generated data for key input parameters (t1/2, Koc, etc.). Model flexibility in ...

  15. A model assessment of polychlorinated dibenzo-p-dioxin and dibenzofuran sources and fate in the Baltic Sea.

    Science.gov (United States)

    Armitage, James M; McLachlan, Michael S; Wiberg, Karin; Jonsson, Per

    2009-06-01

    The contamination of the Baltic Sea with polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) has resulted in restrictions on the marketing and consumption of Baltic Sea fish, making this a priority environmental issue in the European Union. To date there is no consensus on the relative importance of different sources of PCDD/Fs to the Baltic Sea, and hence no consensus on how to address this issue. In this work we synthesized the available information to create a PCDD/F budget for the Baltic Sea, focusing on the two largest basins, the Bothnian Sea and the Baltic Proper. The non-steady state multimedia fate and transport model POPCYCLING-Baltic was employed, using recent data for PCDD/F concentrations in air and sediment as boundary conditions. The PCDD/F concentrations in water predicted by the model were in good agreement with recent measurements. The budget demonstrated that atmospheric deposition was the dominant source of PCDD/Fs to the basins as a whole. This conclusion was supported by a statistical comparison of the PCDD/F congener patterns in surface sediments from accumulation bottoms with the patterns in ambient air, bulk atmospheric deposition, and a range of potential industrial sources. Prospective model simulations indicated that the PCDD/F concentrations in the water column will continue to decrease in the coming years due to the slow response of the Baltic Sea system to falling PCDD/F inputs in the last decades, but that the decrease would be more pronounced if ambient air concentrations were to drop further in the future, for instance as a result of reduced emissions. The study illustrates the usefulness of using monitoring data and multimedia models in an integrated fashion to address complex organic contaminant issues.

  16. Pesticide fate on catchment scale: conceptual modelling of stream CSIA data

    Science.gov (United States)

    Lutz, Stefanie R.; van der Velde, Ype; Elsayed, Omniea F.; Imfeld, Gwenaël; Lefrancq, Marie; Payraudeau, Sylvain; van Breukelen, Boris M.

    2017-10-01

    Compound-specific stable isotope analysis (CSIA) has proven beneficial in the characterization of contaminant degradation in groundwater, but it has never been used to assess pesticide transformation on catchment scale. This study presents concentration and carbon CSIA data of the herbicides S-metolachlor and acetochlor from three locations (plot, drain, and catchment outlets) in a 47 ha agricultural catchment (Bas-Rhin, France). Herbicide concentrations at the catchment outlet were highest (62 µg L-1) in response to an intense rainfall event following herbicide application. Increasing δ13C values of S-metolachlor and acetochlor by more than 2 ‰ during the study period indicated herbicide degradation. To assist the interpretation of these data, discharge, concentrations, and δ13C values of S-metolachlor were modelled with a conceptual mathematical model using the transport formulation by travel-time distributions. Testing of different model setups supported the assumption that degradation half-lives (DT50) increase with increasing soil depth, which can be straightforwardly implemented in conceptual models using travel-time distributions. Moreover, model calibration yielded an estimate of a field-integrated isotopic enrichment factor as opposed to laboratory-based assessments of enrichment factors in closed systems. Thirdly, the Rayleigh equation commonly applied in groundwater studies was tested by our model for its potential to quantify degradation on catchment scale. It provided conservative estimates on the extent of degradation as occurred in stream samples. However, largely exceeding the simulated degradation within the entire catchment, these estimates were not representative of overall degradation on catchment scale. The conceptual modelling approach thus enabled us to upscale sample-based CSIA information on degradation to the catchment scale. Overall, this study demonstrates the benefit of combining monitoring and conceptual modelling of concentration

  17. CASCADER: An M-chain gas-phase radionuclide transport and fate model

    International Nuclear Information System (INIS)

    Lindstrom, F.T.; Cawlfield, D.E.; Emer, D.F.; Shott, G.J.; Donahue, M.E.

    1993-02-01

    Chemicals and radionuclides move either in the gas-phase, liquid-phase, or both phases in soils. They may be acted upon by either biological or abiotic processes through advection and diffusion. Furthermore, parent and daughter radionuclides may decay as they are transported in the soil. CASCADER is a gas-phase, one-space dimensional transport and fate model for M-chain radionuclides in very dry homogeneous or heterogeneous soil. This model contains barometric pressure-induced advection and diffusion together with linear irreversible and linear reversible sorption for each radionuclide. The advection velocity is derived from an embedded air-pumping submodel. The air-pumping submodel is based on an assumption of isothermal conditions, which is driven by barometric pressure. CASCADER allows the concentration of source radionuclides to decay via the classical Bateman chain of simple, first-order kinetic processes. The transported radionuclides also decay via first-order processes while in the soil. A mass conserving, flux-type inlet and exit set of boundary conditions are used. The user must supply the initial distribution for the parent radionuclide in the soil. The initial daughter distribution is found using equilibrium rules. The model is user friendly as it uses a prompt-driven, free-form input. The code is ANSI standard Fortran 77

  18. CASCADER: An m-chain gas-phase radionuclide transport and fate model

    International Nuclear Information System (INIS)

    Lindstrom, F.T.; Cawlfield, D.E.; Emer, D.F.; Shott, G.J.; Donahue, M.E.

    1992-06-01

    Chemicals and radionuclides move either in the gas-phase, liquid-phase, or both phases in soils. They may be acted upon by either biological or abiotic processes as they are advected and/or dispersed. Furthermore, parent and daughter radionuclides may decay as they are transported in the soil. CASCADER is a gas-phase, one space dimensional transport and fate model for an m-chain of radionuclides in very dry soil. This model contains barometric pressure-induced advection and diffusion together with linear irreversible and linear reversible sorption for each radionuclide. The advocation velocity is derived from an embedded air-pumping submodel. The airpumping submodel is based on an assumption of isothermal conditions and is barometric pressure driven. CASCADER allows the concentration of source radionuclides to decay via the classical Bateman chain of simple, first-order kinetic processes. The transported radionuclides also decay via first-order processes while in the soil. A mass conserving, flux-type inlet and exit set of boundary conditions is used. The user must supply the initial distribution for the parent radionuclide in the soil. The initial daughter distribution is found using equilibrium rules. The model is user friendly as it uses a prompt-driven, free-form input. The code is ANSI standard Fortran 77

  19. Evaluating officially reported polycyclic aromatic hydrocarbon emissions in the Athabasca oil sands region with a multimedia fate model

    Science.gov (United States)

    Parajulee, Abha; Wania, Frank

    2014-01-01

    Emissions of organic substances with potential toxicity to humans and the environment are a major concern surrounding the rapid industrial development in the Athabasca oil sands region (AOSR). Although concentrations of polycyclic aromatic hydrocarbons (PAHs) in some environmental samples have been reported, a comprehensive picture of organic contaminant sources, pathways, and sinks within the AOSR has yet to be elucidated. We sought to use a dynamic multimedia environmental fate model to reconcile the emissions and residue levels reported for three representative PAHs in the AOSR. Data describing emissions to air compiled from two official sources result in simulated concentrations in air, soil, water, and foliage that tend to fall close to or below the minimum measured concentrations of phenanthrene, pyrene, and benzo(a)pyrene in the environment. Accounting for evaporative emissions (e.g., from tailings pond disposal) provides a more realistic representation of PAH distribution in the AOSR. Such indirect emissions to air were found to be a greater contributor of PAHs to the AOSR atmosphere relative to reported direct emissions to air. The indirect pathway transporting uncontrolled releases of PAHs to aquatic systems via the atmosphere may be as significant a contributor of PAHs to aquatic systems as other supply pathways. Emission density estimates for the three PAHs that account for tailings pond disposal are much closer to estimated global averages than estimates based on the available emissions datasets, which fall close to the global minima. Our results highlight the need for improved accounting of PAH emissions from oil sands operations, especially in light of continued expansion of these operations. PMID:24596429

  20. Nitrogen Fate in a Phreatic Fluviokarst Watershed: a Stable Isotope, Sediment Tracing, and Numerical Modeling Approach

    Science.gov (United States)

    Husic, A.; Fox, J.; Ford, W. I., III; Agouridis, C.; Currens, J. C.; Taylor, C. J.

    2017-12-01

    Sediment tracing tools provide an insight into provenance, fate, and transport of sediment and, when coupled to stable isotopes, can elucidate in-stream biogeochemical processes. Particulate nitrogen fate in fluviokarst systems is a relatively unexplored area of research partially due to the complex hydrodynamics at play in karst systems. Karst topography includes turbulent conduits that transport groundwater and contaminants at speeds more typical of open channel flows than laminar Darcian flows. While it is accepted that karst hydro-geomorphology represents a hybrid surface-subsurface system for fluid, further investigation is needed to determine whether, and to what extent, karst systems behave like surface agricultural streams or porous media aquifers with respect to their role in nitrogen cycling. Our objective is to gain an understanding of in-conduit nitrogen processes and their effect on net nitrogen-exports from karst springs to larger waterbodies. The authors apply water, sediment, carbon, and nitrogen tracing techniques to analyze water for nitrate, sediment carbon and nitrogen, and stable sediment nitrogen isotope (δ15N). Thereafter, a new numerical model is formulated that: simulates dissolved inorganic nitrogen and sediment nitrogen transformations in the phreatic karst conduit; couples carbon turnover and nitrogen transformations in the model structure; and simulates the nitrogen stable isotope mass balance for the dissolved and sediment phases. Nitrogen tracing data results show a significant increase in δ15N of sediment nitrogen at the spring outlet relative to karst inputs indicating the potential for isotope fractionation during dissolved N uptake by bed sediments in the conduit and during denitrification within bed sediments. The new numerical modeling structure is then used to reproduce the data results and provide an estimate of the relative dominance of N uptake and denitrification within the surficial sediments of the karst conduit system

  1. Communication models in environmental health.

    Science.gov (United States)

    Guidotti, Tee L

    2013-01-01

    Communication models common in environmental health are not well represented in the literature on health communication. Risk communication is a systematic approach to conveying essential information about a specific environmental issue and a framework for thinking about community risk and the alternatives for dealing with it. Crisis communication is intended to provide essential information to people facing an emergency in order to mitigate its effects and to enable them to make appropriate decisions, and it is primarily used in emergency management. Corporate communication is intended to achieve a change in attitude or perception of an organization, and its role in environmental health is usually public relations or to rehabilitate a damaged reputation. Environmental health education is a more didactic approach to science education with respect to health and the environment. Social marketing uses conventional marketing methods to achieve a socially desirable purpose but is more heavily used in health promotion generally. Communication models and styles in environmental health are specialized to serve the needs of the field in communicating with the community. They are highly structured and executed in different ways but have in common a relative lack of emphasis on changing personal or lifestyle behavior compared with health promotion and public health in general and a tendency to emphasize content on specific environmental issues and decision frameworks for protecting oneself or the community through collective action.

  2. Indirect human exposure assessment of airborne lead deposited on soil via a simplified fate and speciation modelling approach.

    Science.gov (United States)

    Pizzol, Massimo; Bulle, Cécile; Thomsen, Marianne

    2012-04-01

    In order to estimate the total exposure to the lead emissions from a municipal waste combustion plant in Denmark, the indirect pathway via ingestion of lead deposited on soil has to be quantified. Multi-media fate models developed for both Risk Assessment (RA) and Life Cycle Assessment (LCA) can be used for this purpose, but present high uncertainties in the assessment of metal's fate. More sophisticated and metal-specific geochemical models exist, that could lower the uncertainties by e.g. accounting for metal speciation, but they require a large amount of data and are unpractical to combine broadly with other fate and dispersion models. In this study, a Simplified Fate & Speciation Model (SFSM) is presented, that is based on the parsimony principle: "as simple as possible, as complex as needed", and that can be used for indirect human exposure assessment in different context like RA and regionalized LCA. SFSM couples traditional multi-media mass balances with empirical speciation models in a tool that has a simple theoretical framework and that is not data-intensive. The model calculates total concentration, dissolved concentration, and free ion activity of Cd, Cu, Ni, Pb and Zn in different soil layers, after accounting for metal deposition and dispersion. The model is tested for these five metals by using data from peer reviewed literature. Results show good accordance between measured and calculated values (factor of 3). The model is used to predict the human exposure via soil to lead initially emitted into air by the waste combustion plant and both the lead cumulative exposure and intake fraction are calculated. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Transcriptional regulation of lineage commitment--a stochastic model of cell fate decisions.

    Directory of Open Access Journals (Sweden)

    Jose Teles

    Full Text Available Molecular mechanisms employed by individual multipotent cells at the point of lineage commitment remain largely uncharacterized. Current paradigms span from instructive to noise-driven mechanisms. Of considerable interest is also whether commitment involves a limited set of genes or the entire transcriptional program, and to what extent gene expression configures multiple trajectories into commitment. Importantly, the transient nature of the commitment transition confounds the experimental capture of committing cells. We develop a computational framework that simulates stochastic commitment events, and affords mechanistic exploration of the fate transition. We use a combined modeling approach guided by gene expression classifier methods that infers a time-series of stochastic commitment events from experimental growth characteristics and gene expression profiling of individual hematopoietic cells captured immediately before and after commitment. We define putative regulators of commitment and probabilistic rules of transition through machine learning methods, and employ clustering and correlation analyses to interrogate gene regulatory interactions in multipotent cells. Against this background, we develop a Monte Carlo time-series stochastic model of transcription where the parameters governing promoter status, mRNA production and mRNA decay in multipotent cells are fitted to experimental static gene expression distributions. Monte Carlo time is converted to physical time using cell culture kinetic data. Probability of commitment in time is a function of gene expression as defined by a logistic regression model obtained from experimental single-cell expression data. Our approach should be applicable to similar differentiating systems where single cell data is available. Within our system, we identify robust model solutions for the multipotent population within physiologically reasonable values and explore model predictions with regard to

  4. Modeling seasonal redox dynamics and the corresponding fate of the pharmaceutical residue phenazone during artificial recharge of groundwater.

    Science.gov (United States)

    Greskowiak, Janek; Prommer, Henning; Massmann, Gudrun; Nützmann, Gunnar

    2006-11-01

    Reactive multicomponent transport modeling was used to investigate and quantify the factors that affect redox zonation and the fate of the pharmaceutical residue phenazone during artificial recharge of groundwater at an infiltration site in Berlin, Germany. The calibrated model and the corresponding sensitivity analysis demonstrated thattemporal and spatial redox zonation at the study site was driven by seasonally changing, temperature-dependent organic matter degradation rates. Breakthrough of phenazone at monitoring wells occurred primarily during the warmer summer months, when anaerobic conditions developed. Assuming a redox-sensitive phenazone degradation behavior the model results provided an excellent agreement between simulated and measured phenazone concentrations. Therefore, the fate of phenazone was shown to be indirectly controlled by the infiltration water temperature through its effect on the aquifer's redox conditions. Other factors such as variable residence times appeared to be of less importance.

  5. Arms race between selfishness and policing: two-trait quantitative genetic model for caste fate conflict in eusocial Hymenoptera.

    Science.gov (United States)

    Dobata, Shigeto

    2012-12-01

    Policing against selfishness is now regarded as the main force maintaining cooperation, by reducing costly conflict in complex social systems. Although policing has been studied extensively in social insect colonies, its coevolution against selfishness has not been fully captured by previous theories. In this study, I developed a two-trait quantitative genetic model of the conflict between selfish immature females (usually larvae) and policing workers in eusocial Hymenoptera over the immatures' propensity to develop into new queens. This model allows for the analysis of coevolution between genomes expressed in immatures and workers that collectively determine the immatures' queen caste fate. The main prediction of the model is that a higher level of polyandry leads to a smaller fraction of queens produced among new females through caste fate policing. The other main prediction of the present model is that, as a result of arms race, caste fate policing by workers coevolves with exaggerated selfishness of the immatures achieving maximum potential to develop into queens. Moreover, the model can incorporate genetic correlation between traits, which has been largely unexplored in social evolution theory. This study highlights the importance of understanding social traits as influenced by the coevolution of conflicting genomes. © 2012 The Author. Evolution© 2012 The Society for the Study of Evolution.

  6. Uncertainty analysis of environmental models

    International Nuclear Information System (INIS)

    Monte, L.

    1990-01-01

    In the present paper an evaluation of the output uncertainty of an environmental model for assessing the transfer of 137 Cs and 131 I in the human food chain are carried out on the basis of a statistical analysis of data reported by the literature. The uncertainty analysis offers the oppotunity of obtaining some remarkable information about the uncertainty of models predicting the migration of non radioactive substances in the environment mainly in relation to the dry and wet deposition

  7. Modeling Environmental Literacy of University Students

    Science.gov (United States)

    Teksoz, Gaye; Sahin, Elvan; Tekkaya-Oztekin, Ceren

    2012-01-01

    The present study proposed an Environmental Literacy Components Model to explain how environmental attitudes, environmental responsibility, environmental concern, and environmental knowledge as well as outdoor activities related to each other. A total of 1,345 university students responded to an environmental literacy survey (Kaplowitz and Levine…

  8. Modelling the geochemical fate and transport of wastewater-derived phosphorus in contrasting groundwater systems

    Science.gov (United States)

    Spiteri, Claudette; Slomp, Caroline P.; Regnier, Pierre; Meile, Christof; Van Cappellen, Philippe

    2007-06-01

    A 1D reactive transport model (RTM) is used to obtain a mechanistic understanding of the fate of phosphorus (P) in the saturated zone of two contrasting aquifer systems. We use the field data from two oxic, electron donor-poor, wastewater-impacted, sandy Canadian aquifers, (Cambridge and Muskoka sites) as an example of a calcareous and non-calcareous groundwater system, respectively, to validate our reaction network. After approximately 10 years of wastewater infiltration, P is effectively attenuated within the first 10 m downgradient of the source mainly through fast sorption onto calcite and Fe oxides. Slow, kinetic sorption contributes further to P removal, while precipitation of phosphate minerals (strengite, hydroxyapatite) is quantitatively unimportant in the saturated zone. Nitrogen (N) dynamics are also considered, but nitrate behaves essentially as a conservative tracer in both systems. The model-predicted advancement of the P plume upon continued wastewater discharge at the calcareous site is in line with field observations. Model results suggest that, upon removal of the wastewater source, the P plume at both sites will persist for at least 20 years, owing to desorption of P from aquifer solids and the slow rate of P mineral precipitation. Sensitivity analyses for the non-calcareous scenario (Muskoka) illustrate the importance of the sorption capacity of the aquifer solids for P in modulating groundwater N:P ratios in oxic groundwater. The model simulations predict the breakthrough of groundwater with high P concentrations and low N:P ratios after 17 years at 20 m from the source for an aquifer with low sorption capacity (< 0.02% w/w Fe(OH) 3). In this type of system, denitrification plays a minor role in lowering the N:P ratios because it is limited by the availability of labile dissolved organic matter.

  9. Oceanographic and behavioural assumptions in models of the fate of coral and coral reef fish larvae.

    Science.gov (United States)

    Wolanski, Eric; Kingsford, Michael J

    2014-09-06

    A predictive model of the fate of coral reef fish larvae in a reef system is proposed that combines the oceanographic processes of advection and turbulent diffusion with the biological process of horizontal swimming controlled by olfactory and auditory cues within the timescales of larval development. In the model, auditory cues resulted in swimming towards the reefs when within hearing distance of the reef, whereas olfactory cues resulted in the larvae swimming towards the natal reef in open waters by swimming against the concentration gradients in the smell plume emanating from the natal reef. The model suggested that the self-seeding rate may be quite large, at least 20% for the larvae of rapidly developing reef fish species, which contrasted with a self-seeding rate less than 2% for non-swimming coral larvae. The predicted self-recruitment rate of reefs was sensitive to a number of parameters, such as the time at which the fish larvae reach post-flexion, the pelagic larval duration of the larvae, the horizontal turbulent diffusion coefficient in reefal waters and the horizontal swimming behaviour of the fish larvae in response to auditory and olfactory cues, for which better field data are needed. Thus, the model suggested that high self-seeding rates for reef fish are possible, even in areas where the 'sticky water' effect is minimal and in the absence of long-term trapping in oceanic fronts and/or large-scale oceanic eddies or filaments that are often argued to facilitate the return of the larvae after long periods of drifting at sea. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  10. Fate of challenge schistosomula in the murine anti-schistosome vaccine model

    International Nuclear Information System (INIS)

    Von Lichtenberg, F.; Correa-Oliveira, R.; Sher, A.

    1985-01-01

    Mice exposed to irradiated cercariae of Schistosoma mansoni develop a partial resistance to subsequent parasite challenge. In this study the authors utilized histopathologic methods to investigate the fate of both the immunizing and challenge cercariae in C57BL/6J mice. After immunization by percutaneous infection, a large number of the 50 Kr irradiated organisms could be detected in tissue sections of lung. However, as early as 2 weeks after immunization, the majority of these schistosomula apparently had died, leaving residual inflammatory foci. The numbers of these foci then gradually declined during the next 4 weeks of examination. Cercarial challenge of mice vaccinated 4 weeks previously provoked an intense eosinophil-enriched inflammatory response in percutaneously exposed ear pinnae. Despite these pronounced tissue reactions, no evidence of significant parasite damage or attrition was detected in this migration site. In contrast, schistosomula arriving in the lungs of vaccinated mice produced a greater number of residual inflammatory foci than did larvae appearing in the lungs of normal mice. In addition, challenge schistosomula were cleared from the lungs of vaccinated mice at a slower rate than they were from the lungs of control mice. These observations suggest that the lung is a major site of parasite attrition for both immunizing and challenge infections in the mouse irradiated vaccine model

  11. Contaminant fate and transport in the Venice Lagoon: results from a multi-segment multimedia model.

    Science.gov (United States)

    Sommerfreund, J K; Gandhi, N; Diamond, M L; Mugnai, C; Frignani, M; Capodaglio, G; Gerino, M; Bellucci, L G; Giuliani, S

    2010-03-01

    Contaminant loadings to the Venice Lagoon peaked from 1950s-1980s and although they have since declined, contaminant concentrations remain elevated in sediment and seafood. In order to identify the relative importance of contaminant sources, inter-media exchange and removal pathways, a modified 10-segment fugacity/aquivalence-based model was developed for octachlorodibenzodioxin/furan (OCDD/F), PCB-180, Pb and Cu in the Venice Lagoon. Results showed that in-place pollution nearby the industrial area, current industrial discharges, and tributary loadings were the main sources of contaminants to the lagoon, with negligible contributions from the atmosphere. The fate of these contaminants was governed by sediment-water exchange with simultaneous advective transport by water circulation. Contaminants circulated amongst the northern and central basins with a small fraction reaching the far southern basin and the Chioggia inlet. As a consequence, we estimated limited contaminant transfer to the Adriatic Sea, trapping the majority of contaminants in the sediment in this "average" circulation scenario which does not account for periodic flooding events. (c) 2009 Elsevier Inc. All rights reserved.

  12. Nitrogen fate model for gas-phase ammonia-enhanced in situ bioventing

    International Nuclear Information System (INIS)

    Marshall, T.R.

    1995-01-01

    Subsurface bioremediation of contaminants is sometimes limited by the availability of nitrogen. Introduction of gaseous ammonia to the subsurface is a feasible and economical approach to enhance biodegradation in some environments. A gaseous nutrient source may be a practical option for sites where surface application of liquid nutrients is not possible, such as sites with shallow groundwater or sites with surface operations. A conceptual nitrogen fate model was developed to provide remediation scientists and engineers with some practical guidelines in the use of ammonia-enhanced bioventing. Ammonia supplied to the subsurface dissolves readily in soil moisture and sorbs strongly to soil particles. The ammonium ion is the preferred nutrient form of many microorganisms. Some of the ammonia will be converted to nitrate by ammonia-oxidizing organisms. Field monitoring data from an operating ammonia-enhanced bioventing remediation site for diesel fuel contamination are presented. Conservative additions of ammonia promoted appreciable increases in evolved carbon dioxide and rate of oxygen utilization. An overabundance of added ammonia promoted formation of methane from likely anaerobic hydrocarbon degradation in the presence of nitrate as the electron acceptor

  13. 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

  14. Sources, fate, and transport of nitrogen and phosphorus in the Chesapeake Bay watershed-An empirical model

    Science.gov (United States)

    Ator, Scott W.; Brakebill, John W.; Blomquist, Joel D.

    2011-01-01

    Spatially Referenced Regression on Watershed Attributes (SPARROW) was used to provide empirical estimates of the sources, fate, and transport of total nitrogen (TN) and total phosphorus (TP) in the Chesapeake Bay watershed, and the mean annual TN and TP flux to the bay and in each of 80,579 nontidal tributary stream reaches. Restoration efforts in recent decades have been insufficient to meet established standards for water quality and ecological conditions in Chesapeake Bay. The bay watershed includes 166,000 square kilometers of mixed land uses, multiple nutrient sources, and variable hydrogeologic, soil, and weather conditions, and bay restoration is complicated by the multitude of nutrient sources and complex interacting factors affecting the occurrence, fate, and transport of nitrogen and phosphorus from source areas to streams and the estuary. Effective and efficient nutrient management at the regional scale in support of Chesapeake Bay restoration requires a comprehensive understanding of the sources, fate, and transport of nitrogen and phosphorus in the watershed, which is only available through regional models. The current models, Chesapeake Bay nutrient SPARROW models, version 4 (CBTN_v4 and CBTP_v4), were constructed at a finer spatial resolution than previous SPARROW models for the Chesapeake Bay watershed (versions 1, 2, and 3), and include an updated timeframe and modified sources and other explantory terms.

  15. Modeling Quantum Dot Nanoparticle Fate and Transport in Saturated Porous Media under Varying Flow Conditions

    Science.gov (United States)

    Becker, M. D.; Wang, Y.; Englehart, J.; Pennell, K. D.; Abriola, L. M.

    2010-12-01

    As manufactured nanomaterials become more prevalent in commercial and industrial applications, the development of mathematical models capable of predicting nanomaterial transport and retention in subsurface systems is crucial to assessing their fate and distribution in the environment. A systematic modeling approach based on a modification of clean-bed filtration theory was undertaken to elucidate mechanisms governing the transport and deposition behavior of quantum dots in saturated quartz sand as a function of grain size and flow velocity. The traditional deposition governing equation, which assumes irreversible attachment by a first-order rate (katt), was modified to include a maximum or limiting retention capacity (Smax) and first-order detachment of particles from the solid phase (kdet). Quantum dot mobility experiments were performed in columns packed with three size fractions of Ottawa sand (d50 = 125, 165, and 335 μm) at two different pore-water velocities (0.8 m/d and 7.6 m/d). The CdSe quantum dots in a CdZnS shell and polyacrylic acid coating were negatively charged (zeta potential measured ca. -35 mV) with a hydrodynamic diameter of approximately 30 nm. Fitted values of katt, Smax, and kdet were obtained for each transport and deposition experiment through the implementation of a nonlinear least-squares routine developed to fit the model to experimental breakthrough and retention data via multivariate optimization. Fitted attachment rates and retention capacities increased exponentially with decreasing grain size at both flow rates, while no discernable trend was apparent for the fitted detachment rates. Maximum retention capacity values were plotted against a normalized mass flux expression, which accounts for flow conditions and grain size. A power function fit to the data yielded a dependence that was consistent with a previous study undertaken with fullerene nanoparticles.

  16. The OECD expert meeting on ecotoxicology and environmental fate — Towards the development of improved OECD guidelines for the testing of nanomaterials

    International Nuclear Information System (INIS)

    Kühnel, Dana; Nickel, Carmen

    2014-01-01

    On behalf of the OECD Working Party on Manufactured Nanomaterials (WPMN) an expert meeting on ecotoxicology and environmental fate of nanomaterials (NMs) took place in January 2013 in Berlin. At this meeting experts from science, industry and regulatory bodies discussed the applicability of OECD test guidelines (TGs) for chemicals to nanomaterials. The objective was to discuss the current state of the relevant science and provide recommendations to the OECD WPMN on (1) the need for updating current OECD TGs and the need for developing new ones specific to nanomaterials; and (2) guidance needed for the appropriate and valid testing of environmental fate and ecotoxicity endpoints for NMs. Experts at the workshop agreed that the majority of the OECD TG for chemicals were generally applicable for the testing of NM, with the exception of TG 105 (water solubility) and 106 (adsorption-desorption). Additionally, the workshop also highlighted considerations when conducting OECD chemical TG on nanomaterials (e.g., sample preparation, dispersion, analysis, dosimetry and characterisation). These considerations will lead to the future development of proposals for new TG and guidance documents (GDs) to ensure that OECD TG give meaningful, repeatable, and accurate results when used for nanomaterials. This report provides a short overview of topics discussed during the meeting and the main outcomes. A more detailed report of the workshop will become available through the OECD, however, due to the urgency of having OECD TG relevant for nanomaterials, this brief report is being shared with the scientific community through this communication. - Highlights: • OECD test guidelines (TGs) were developed for the testing of conventional chemicals. • Need for discussion on applicability of current TGs to nanomaterials • An expert meeting addressing this issue was held. • The focus was on TGs covering ecotoxicology and environmental fate. • Recommendations for updating current OECD

  17. Modeling of geo-material durability and contaminant fate in recycling or disposal of industrial and radioactive waste

    International Nuclear Information System (INIS)

    De Windt, L.

    2011-01-01

    This report deals with the HYTEC model, coupling chemical and hydrodynamic processes, and its application to the recycling of inorganic wastes and the disposal of hazardous and radioactive wastes. A common feature is the assessment of geo-material durability while submitted to chemical disturbances by their industrial or natural environment and, reciprocally, the quantification of contaminant fate in soils and aquifers. Research papers in a first section numerically oriented, HYTEC is validated by means of an intercomparison exercise based on oxidative UO 2 dissolution and the subsequent migration of U species in subsurface environments. A numerical approach of leaching tests is also discussed. Several researches based on HYTEC follows. The evolution of the cement/clay interface is simulated in the framework of the multi-barrier system of radioactive waste disposal and the Tournemire engineering analog; discriminating between the physical and chemical key processes. The physico-chemical processes of cement biodegradation by fungi are investigated with a focus on acidic hydrolysis and complexation by biogenic carboxylic acids. Modeling of source-terms and ageing with respect to contaminant migration is discussed in the case of the chemical alteration of spent fuel pellets under disposal conditions by considering radiolytic dissolution, inhibiting effect and radioactive decay, and by analyzing the effect of fractures on the containment properties of subsurface disposal facilities of stabilized/solidified waste. Leaching lab experiments applied to steel slag and the chemical evolution of leachate from MSWI sub-bases of two pilot roads over 10 years are eventually modelled to better estimate the environmental impact of such recycling scenarios. On-going research In the straight lines of the modeling of radioactive waste disposal, a first perspective is to investigate the transient states driven by thermal gradient and water re-saturation of the near-field barriers and

  18. A pollution fate and transport model application in a semi-arid region: Is some number better than no number?

    Science.gov (United States)

    Özcan, Zeynep; Başkan, Oğuz; Düzgün, H Şebnem; Kentel, Elçin; Alp, Emre

    2017-10-01

    Fate and transport models are powerful tools that aid authorities in making unbiased decisions for developing sustainable management strategies. Application of pollution fate and transport models in semi-arid regions has been challenging because of unique hydrological characteristics and limited data availability. Significant temporal and spatial variability in rainfall events, complex interactions between soil, vegetation and topography, and limited water quality and hydrological data due to insufficient monitoring network make it a difficult task to develop reliable models in semi-arid regions. The performances of these models govern the final use of the outcomes such as policy implementation, screening, economical analysis, etc. In this study, a deterministic distributed fate and transport model, SWAT, is applied in Lake Mogan Watershed, a semi-arid region dominated by dry agricultural practices, to estimate nutrient loads and to develop the water budget of the watershed. To minimize the discrepancy due to limited availability of historical water quality data extensive efforts were placed in collecting site-specific data for model inputs such as soil properties, agricultural practice information and land use. Moreover, calibration parameter ranges suggested in the literature are utilized during calibration in order to obtain more realistic representation of Lake Mogan Watershed in the model. Model performance is evaluated using comparisons of the measured data with 95%CI for the simulated data and comparison of unit pollution load estimations with those provided in the literature for similar catchments, in addition to commonly used evaluation criteria such as Nash-Sutcliffe simulation efficiency, coefficient of determination and percent bias. These evaluations demonstrated that even though the model prediction power is not high according to the commonly used model performance criteria, the calibrated model may provide useful information in the comparison of the

  19. Ocean Dredged Material Disposal Site (ODMDS) Authorization and Short-Term FATE (STFATE) Model Analysis: 2014-2015 Working Group Findings Report

    Science.gov (United States)

    2016-03-01

    fractions A grain size or sieve analysis typically yields the mass fraction of each particle size class after dispersing all of the material. However...ER D C TR -1 6- 2 Ocean Dredged Material Disposal Site (ODMDS) Authorization and Short-Term FATE (STFATE) Model Analysis 2014 – 2015...Term FATE (STFATE) Model Analysis 2014 – 2015 Working Group Findings Report Jase D. Ousley Coastal and Hydraulics Laboratory U.S. Army Engineer

  20. Modelling the fate of sulphur-35 in crops. 2. Development and validation of the CROPS-35 model

    International Nuclear Information System (INIS)

    Collins, Chris; Cunningham, Nathan

    2005-01-01

    Gas-cooled nuclear power plants in the UK release sulphur-35 during their routine operation, which can be readily assimilated by vegetation. It is therefore necessary to be able to model the uptake of such releases in order to quantify any potential contamination of the food chain. A model is described which predicts the concentration of 35 S in crop components following an aerial gaseous release. Following deposition the allocation to crop components is determined by an export function from a labile pool, the leaves, to those components growing most actively post exposure. The growth rates are determined by crop growth data, which is also used to determine the concentration. The loss of activity is controlled by radioactive decay only. The paper describes the calibration and the validation of the model. To improve the model, further experimental work is required particularly on the export kinetics of 35 S. It may be possible to adapt such a modelling approach to the prediction of crop content for gaseous releases of 3 H and 14 C from nuclear facilities. - The calibration and validation of a model for the prediction of the fate of 35 S in vegetation is described

  1. Modeling the Transport and Fate of Fecal Pollution and Nutrients of Miyun Reservoir

    Science.gov (United States)

    Liu, L.; Fu, X.; Wang, G.

    2009-12-01

    Miyun Reservoir, a mountain valley reservoir, is located 100 km northeast of Beijing City. Besides the functions of flood control, irrigation and fishery for Beijing area, Miyun Reservoir is the main drinking water storage for Beijing city. The water quality is therefore of great importance. Recently, the concentration of fecal pollution and nutrients in the reservoir are constantly rising to arrest the attention of Beijing municipality. Fecal pollution from sewage is a significant public health concern due to the known presence of human viruses and parasites in these discharges. To investigate the transport and fate of the fecal pollution and nutrients at Miyun reservoir and the health risks associated with drinking and fishery, the reservoir and two tributaries, Chaohe river and Baihe river discharging into it are being examined for bacterial, nutrients and other routine pollution. To understand the relative importance of different processes influencing pollution transport and inactivation, a finite-element model of surf-zone hydrodynamics (coupled with models for temperature, fecal pollution, nutrients and other routine contaminants) is used. The developed models are being verified by the observed water quality data including water temperature, conductivities and dissolved oxygen from the reservoir and its tributaries. Different factors impacting the inactivation of fecal pollution and the transport of nutrients such as water temperature, sedimentation, sunlight insolation are evaluated for Miyun reservoir by a sensitivity analysis analogized from the previous research of Lake Michigan (figure 1, indicating that solar insolation dominates the inactivation of E. Coli, an indicator of fecal pollution, Liu et al. 2006). The calibrated modeling system can be used to temporally and spatially simulate and predict the variation of the concentration of fecal pollution and nutrients of Miyun reservoir. Therefore this research can provide a forecasting tool for the

  2. Modeling the fate of organic micropollutants during river bank filtration (Berlin, Germany).

    Science.gov (United States)

    Henzler, Aline F; Greskowiak, Janek; Massmann, Gudrun

    2014-01-01

    Emerging organic contaminants (EOCs) are frequently detected in urban surface water and the adjacent groundwater and are therefore an increasing problem for potable water quality. River bank filtration (RBF) is a beneficial pretreatment step to improve surface water quality for potable use. Removal is mainly caused by microbial degradation of micropollutants, while sorption retards the transport. The quantification of biodegradation and adsorption parameters for EOCs at field scale is still scarce. In this study, the fate and behavior of a range of organic compounds during RBF were investigated using a two dimensional numerical flow- and transport model. The data base used emanated from a project conducted in Berlin, Germany (NASRI: Natural and Artificial Systems for Recharge and Infiltration). Oxygen isotope signatures and hydraulic head data were used for model calibration. Afterwards, twelve organic micropollutants were simulated with a reactive transport model. Three compounds (primidone, EDTA, and AMDOPH) showed conservative behavior (no biodegradation or sorption). For the nine remaining compounds (1.5 NDSA, AOX, AOI, MTBE, carbamazepine, clindamycin, phenazone, diclofenac and sulfamethoxazole), degradation and/or sorption was observed. 1.5 NDSA and AOX were not sorbed, but slightly degraded with model results for λ=2.25e(-3) 1/d and 2.4e(-3) 1/d. For AOI a λ=0.0106 1/d and R=1 were identified. MTBE could be characterized well assuming R=1 and a low 1st order degradation rate constant (λ=0.0085 1/d). Carbamazepine degraded with a half life time of about 66 days after a threshold value of 0.2-0.3 μg/L was exceeded and retarded slightly (R=1.7). Breakthrough curves of clindamycin, phenazone, diclofenac and sulfamethoxazole could be fitted less well, probably due to the dependency of degradation on temperature and redox conditions, which are highly transient at the RBF site. Conditions range from oxic to anoxic (up to iron-reducing), with the oxic and

  3. Investigating Particle Transport and Fate in the Sacramento–San Joaquin Delta Using a Particle-Tracking Model

    Directory of Open Access Journals (Sweden)

    Wim J. Kimmerer

    2008-02-01

    Full Text Available Movements of pelagic organisms in the tidal freshwater regions of estuaries are sensitive to the movements of water. In the Sacramento-San Joaquin Delta—the tidal freshwater reach of the San Francisco Estuary—such movements are key to losses of fish and other organisms to entrainment in large water-export facilities. We used the Delta Simulation Model-2 hydrodynamic model and its particle tracking model to examine the principal determinants of entrainment losses to the export facilities and how movement of fish through the Delta may be influenced by flow. We modeled 936 scenarios for 74 different conditions of flow, diversions, tides, and removable barriers to address seven questions regarding hydrodynamics and entrainment risk in the Delta. Tide had relatively small effects on fate and residence time of particles. Release location and hydrology interacted to control particle fate and residence time. The ratio of flow into the export facilities to freshwater flow into the Delta (export:inflow or EI ratio was a useful predictor of entrainment probability if the model were allowed to run long enough to resolve particles’ ultimate fate. Agricultural diversions within the Delta increased total entrainment losses and altered local movement patterns. Removable barriers in channels of the southern Delta and gates in the Delta Cross Channel in the northern Delta had minor effects on particles released in the rivers above these channels. A simulation of losses of larval delta smelt showed substantial cumulative losses depending on both inflow and export flow. A simulation mimicking mark–recapture experiments on Chinook salmon smolts suggested that both inflow and export flow may be important factors determining survival of salmon in the upper estuary. To the extent that fish behave passively, this model is probably suitable for describing Delta-wide movement, but it is less suitable for smaller scales or alternative configurations of the Delta.

  4. What determines PCB concentrations in soils in rural and urban areas? Insights from a multi-media fate model for Switzerland as a case study.

    Science.gov (United States)

    Glüge, Juliane; Bogdal, Christian; Scheringer, Martin; Hungerbühler, Konrad

    2016-04-15

    Polychlorinated biphenyls (PCBs) are banned worldwide under the Stockholm Convention on Persistent Organic Pollutants. However, PCBs are still emitted in appreciable amounts from remaining primary sources in urban areas or landfills and are ubiquitous environmental contaminants, inter alia in soil and air. Concentrations of PCBs have been measured in various media by numerous studies worldwide. However, monitoring data do not always provide quantitative information about transport processes between different media, deposition fluxes to ground, or distribution of PCBs between environmental compartments. Also future trends in environmental contamination by PCBs cannot be predicted from monitoring data, but such information is highly relevant for decision-makers. Here, we present a new regionally resolved dynamic multimedia mass balance model for Switzerland to investigate the origin of PCBs in air and to investigate their long-term fate and mass balance in the environment. The model was validated with existing field data for PCBs. We find that advective inflow of PCBs from outside Switzerland into the atmospheric boundary layer is responsible for 80% of PCBs present in air in Switzerland, whereas Swiss emissions cause the remaining 20%. Furthermore, we show that the atmospheric deposition of the higher-chlorinated PCBs is dominated by particle-bound deposition, whereas the deposition of the lower-chlorinated PCBs is a combination of particle-bound and gaseous deposition. The volume fraction of particles in air is in both cases an important factor driving the deposition of PCBs to ground and, thus, contributing to the higher concentrations of PCBs generally observed in populated and polluted areas. Regional emissions influence the deposition fluxes only to a limited extent. We also find that secondary emissions from environmental reservoirs do not exceed primary emissions for all PCB congeners until at least 2036. Finally, we use our model to evaluate the effect of

  5. Chloride ion transport and fate in oilfield wastewater reuse by interval dynamic multimedia aquivalence model.

    Science.gov (United States)

    Hu, Y; Zhang, C; Wang, D Z; Wen, J Y; Chen, M H; Li, Y

    2013-01-01

    A surface flow constructed wetland was built up to dispose of oilfield wastewater with a high level of inorganic salt ions. Chlorine ion (Cl(-)) was selected as an indicator of soil secondary salinization, and an interval dynamic multimedia aquivalence (IDMA) model was developed to investigate the dynamic multimedia environmental (air, water, soil, flora, and groundwater) effects of Cl(-) in the wastewater irrigation process between 2002 and 2020. The modeled Cl(-) concentrations were in good agreement with the measured ones, as indicated by the interval average logarithmic residual errors (IALREs) being generally lower than 0.5 logarithmic units. The model results showed that the temporal trends of Cl(-) concentrations in the multimedia environments represented a relatively steady state. More than 97.00% of the mass exchange was finished between soil and groundwater compartments, and Cl(-) finally outputted the environmental system by the pathways of advection outflows in the water (71.03%) and groundwater (24.02%). Soil (59.17%) was the dominant sink of Cl(-). It was revealed that the high level of Cl(-) in oilfield wastewater was well treated by the constructed wetland, and there was not a significant environmental effect of soil secondary salinization in the oilfield wastewater reused for the constructed wetland irrigation.

  6. Modeling the Fate of Expiratory Aerosols and the Associated Infection Risk in an Aircraft Cabin Environment

    DEFF Research Database (Denmark)

    Wan, M.P.; To, G.N.S.; Chao, C.Y.H.

    2009-01-01

    to estimate the risk of infection by contact. The environmental control system (ECS) in a cabin creates air circulation mainly in the lateral direction, making lateral dispersions of aerosols much faster than longitudinal dispersions. Aerosols with initial sizes under 28 m in diameter can stay airborne......The transport and deposition of polydispersed expiratory aerosols in an aircraft cabin were simulated using a Lagrangian-based model validated by experiments conducted in an aircraft cabin mockup. Infection risk by inhalation was estimated using the aerosol dispersion data and a model was developed...

  7. In silico environmental chemical science: properties and processes from statistical and computational modelling

    Energy Technology Data Exchange (ETDEWEB)

    Tratnyek, P. G.; Bylaska, Eric J.; Weber, Eric J.

    2017-01-01

    Quantitative structure–activity relationships (QSARs) have long been used in the environmental sciences. More recently, molecular modeling and chemoinformatic methods have become widespread. These methods have the potential to expand and accelerate advances in environmental chemistry because they complement observational and experimental data with “in silico” results and analysis. The opportunities and challenges that arise at the intersection between statistical and theoretical in silico methods are most apparent in the context of properties that determine the environmental fate and effects of chemical contaminants (degradation rate constants, partition coefficients, toxicities, etc.). The main example of this is the calibration of QSARs using descriptor variable data calculated from molecular modeling, which can make QSARs more useful for predicting property data that are unavailable, but also can make them more powerful tools for diagnosis of fate determining pathways and mechanisms. Emerging opportunities for “in silico environmental chemical science” are to move beyond the calculation of specific chemical properties using statistical models and toward more fully in silico models, prediction of transformation pathways and products, incorporation of environmental factors into model predictions, integration of databases and predictive models into more comprehensive and efficient tools for exposure assessment, and extending the applicability of all the above from chemicals to biologicals and materials.

  8. In silico environmental chemical science: properties and processes from statistical and computational modelling.

    Science.gov (United States)

    Tratnyek, Paul G; Bylaska, Eric J; Weber, Eric J

    2017-03-22

    Quantitative structure-activity relationships (QSARs) have long been used in the environmental sciences. More recently, molecular modeling and chemoinformatic methods have become widespread. These methods have the potential to expand and accelerate advances in environmental chemistry because they complement observational and experimental data with "in silico" results and analysis. The opportunities and challenges that arise at the intersection between statistical and theoretical in silico methods are most apparent in the context of properties that determine the environmental fate and effects of chemical contaminants (degradation rate constants, partition coefficients, toxicities, etc.). The main example of this is the calibration of QSARs using descriptor variable data calculated from molecular modeling, which can make QSARs more useful for predicting property data that are unavailable, but also can make them more powerful tools for diagnosis of fate determining pathways and mechanisms. Emerging opportunities for "in silico environmental chemical science" are to move beyond the calculation of specific chemical properties using statistical models and toward more fully in silico models, prediction of transformation pathways and products, incorporation of environmental factors into model predictions, integration of databases and predictive models into more comprehensive and efficient tools for exposure assessment, and extending the applicability of all the above from chemicals to biologicals and materials.

  9. A dynamic contaminant fate model of organic compound: a case study of Nitrobenzene pollution in Songhua River, China.

    Science.gov (United States)

    Wang, Ce; Feng, Yujie; Zhao, Shanshan; Li, Bai-Lian

    2012-06-01

    A one-dimensional dynamic contaminant fate model, coupling kinematic wave flow option with advection-dispersion-reaction equation, has been applied to predict Nitrobenzene pollution emergency in Songhua River, China that occurred on November 13, 2005. The model includes kinetic processes including volatilization, photolysis and biodegradation, and diffusive mass exchange between water column and sediment layer as a function of particles settling and resuspension. Four kinds of quantitative statistical tests, namely Nash-Sutcliffe efficiency, percent bias, ratio of root-mean-square to the standard deviation of monitoring data and Theil's inequality coefficient, are adopted to evaluate model performance. The results generally show that the modeled and detected concentrations exhibit good consistency. Flow velocity in the river is most sensitive parameter to Nitrobenzene concentration in water column based on sensitivity analysis of input parameters. It indicates flow velocity has important impact on both distribution and variance of contaminant concentration. The model performs satisfactory for prediction of organic pollutant fate in Songhua River, with the ability to supply necessary information for pollution event control and early warning, which could be applied to similar long natural rivers. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Simulation of the fate of faecal bacteria in estuarine and coastal waters based on a fractionated sediment transport model

    Science.gov (United States)

    Yang, Chen; Liu, Ying

    2017-08-01

    A two-dimensional depth-integrated numerical model is refined in this paper to simulate the hydrodynamics, graded sediment transport process and the fate of faecal bacteria in estuarine and coastal waters. The sediment mixture is divided into several fractions according to the grain size. A bed evolution model is adopted to simulate the processes of the bed elevation change and sediment grain size sorting. The faecal bacteria transport equation includes enhanced source and sink terms to represent bacterial kinetic transformation and disappearance or reappearance due to sediment deposition or re-suspension. A novel partition ratio and dynamic decay rates of faecal bacteria are adopted in the numerical model. The model has been applied to the turbid water environment in the Bristol Channel and Severn estuary, UK. The predictions by the present model are compared with field data and those by non-fractionated model.

  11. Environmental model for a capital city

    Directory of Open Access Journals (Sweden)

    Claudia Eugenia Toca Torres

    2013-06-01

    Full Text Available From a review of the various options for modeling a sustainable development in its environmental dimension, this research proposes a model of environmental impact for Bogota, using the Vensim PLE software to model the pollution, the pollution load and soil contamination. The model includes a limited number of endogenous variables, as well as a greater number of exogenous variables. This modeling allows us to anticipate the environmental situation in the capital, in order to support public policies for addressing issues such as economic sanctions and moral regulations on emissions, discharges and waste, environmental measures and environmentally friendly practices

  12. Review and assessment of models used to predict the fate of radionuclides in lakes

    International Nuclear Information System (INIS)

    Monte, Luigi; Brittain, John E.; Haakanson, Lars; Heling, Rudie; Smith, Jim T.; Zheleznyak, Mark

    2003-01-01

    A variety of models for predicting the behaviour of radionuclides in fresh water ecosystems have been developed and tested during recent decades within the framework of many international research projects. These models have been implemented in Computerised Decision Support Systems (CDSS) for assisting the appropriate management of fresh water bodies contaminated by radionuclides. The assessment of the state-of-the-art and the consolidation of these CDSSs has been envisaged, by the scientific community, as a primary necessity for the rationalisation of the sector. The classification of the approaches of the various models, the determination of their essential features, the identification of similarities and differences among them and the definition of their application domains are all essential for the harmonisation of the existing CDSSs and for the possible development and improvement of reference models that can be widely applied in different environmental conditions. The present paper summarises the results of the assessment and evaluation of models for predicting the behaviour of radionuclides in lacustrine ecosystems. Such models were developed and tested within major projects financed by the European Commission during its 4th Framework Programme (1994-1998). The work done during the recent decades by many modellers at an international level has produced some consolidated results that are widely accepted by most experts. Nevertheless, some new results have arisen from recent studies and certain model improvements are still necessary

  13. A hybrid mathematical modeling approach of the metabolic fate of a fluorescent sphingolipid analogue to predict cancer chemosensitivity.

    Science.gov (United States)

    Molina-Mora, J A; Kop-Montero, M; Quirós-Fernández, I; Quiros, S; Crespo-Mariño, J L; Mora-Rodríguez, R A

    2018-04-13

    Sphingolipid (SL) metabolism is a complex biological system that produces and transforms ceramides and other molecules able to modulate other cellular processes, including survival or death pathways key to cell fate decisions. This signaling pathway integrates several types of stress signals, including chemotherapy, into changes in the activity of its metabolic enzymes, altering thereby the cellular composition of bioactive SLs. Therefore, the SL pathway is a promising sensor of chemosensitivity in cancer and a target hub to overcome resistance. However, there is still a gap in our understanding of how chemotherapeutic drugs can disturb the SL pathway in order to control cellular fate. We propose to bridge this gap by a systems biology approach to integrate i) a dynamic model of SL analogue (BODIPY-FL fluorescent-sphingomyelin analogue, SM-BOD) metabolism, ii) a Gaussian mixture model (GMM) of the fluorescence features to identify how the SL pathway senses the effect of chemotherapy and iii) a fuzzy logic model (FLM) to associate SL composition with cell viability by semi-quantitative rules. Altogether, this hybrid model approach was able to predict the cell viability of double experimental perturbations with chemotherapy, indicating that the SL pathway is a promising sensor to design strategies to overcome drug resistance in cancer. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Fate of acetone in an outdoor model stream with a nitrate supplement, southern Mississippi, U.S.A.

    Science.gov (United States)

    Rathbun, R.E.; Stephens, D.W.; Tai, D.Y.

    1991-01-01

    The fate of acetone in an outdoor model stream to which nitrate was added as a nutrient supplement was determined. The stream, in southern Mississippi, U.S.A. was 234 m long. Water was supplied to the stream by an artesian well at about 1.21 s-1, resulting in a mean water velocity of about 0.5 m min-1. Acetone was injected continuously for 26 days resulting in concentrations of 20-40 mg l-1. A nitrate solution was injected for 21 days resulting in an instream concentration of about 1.7 mg l-1 at the upstream end of the stream. Rhodamine-WT dye was used to determine the travel time and dispersion characteristics of the stream, and t-butyl alcohol was used to determine the volatilization characteristics. Volatilization controlled the fate of acetone in the model stream. The lack of substantial bacterial degradation of acetone was contrary to expectations based on the results of laboratory degradation studies using model stream water enriched with nitrate. A possible explanation for the lack of significant degradation in the model stream may be the limited 6-h residence time of the acetone in the stream. ?? 1991.

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

    International Nuclear Information System (INIS)

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

    2011-01-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Li Rong; Yang Fuquan; Sloan, James J [Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, ON N2L 3G1 (Canada); Scholtz, M Trevor, E-mail: sloanj@connect.uwaterloo.ca [ORTECH Environmental, 2395 Speakman Drive, Mississauga, ON L5K 1B3 (Canada)

    2011-07-15

    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.

  17. 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.

  18. Cell fate determination dynamics in bacteria

    Science.gov (United States)

    Kuchina, Anna; Espinar, Lorena; Cagatay, Tolga; Garcia-Ojalvo, Jordi; Suel, Gurol

    2010-03-01

    The fitness of an organism depends on many processes that serve the purpose to adapt to changing environment in a robust and coordinated fashion. One example of such process is cellular fate determination. In the presence of a variety of alternative responses each cell adopting a particular fate represents a ``choice'' that must be tightly regulated to ensure the best survival strategy for the population taking into account the broad range of possible environmental challenges. We investigated this problem in the model organism B.Subtilis which under stress conditions differentiates terminally into highly resistant spores or initiates an alternative transient state of competence. The dynamics underlying cell fate choice remains largely unknown. We utilize quantitative fluorescent microscopy to track the activities of genes involved in these responses on a single-cell level. We explored the importance of temporal interactions between competing cell fates by re- engineering the differentiation programs. I will discuss how the precise dynamics of cellular ``decision-making'' governed by the corresponding biological circuits may enable cells to adjust to diverse environments and determine survival.

  19. 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

    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......The increasing efforts in reducing the emission of micropollutants (MP) into the natural aquatic environment require the development of modelling tools to support the decision making process. This article presents a library of dynamic modelling tools for estimating MP fluxes within Integrated Urban...... Wastewater and Stormwater system (IUWS – including drainage network, stormwater treatment units, wastewater treatment plants, sludge treatment, and the receiving water body). The models are developed by considering the high temporal variability of the processes taking place in the IUWS, providing a basis...

  20. A coupled modelling effort to study the fate of contaminated sediments downstream of the Coles Hill deposit, Virginia, USA

    Directory of Open Access Journals (Sweden)

    C. F. Castro-Bolinaga

    2015-03-01

    Full Text Available This paper presents the preliminary results of a coupled modelling effort to study the fate of tailings (radioactive waste-by product downstream of the Coles Hill uranium deposit located in Virginia, USA. The implementation of the overall modelling process includes a one-dimensional hydraulic model to qualitatively characterize the sediment transport process under severe flooding conditions downstream of the potential mining site, a two-dimensional ANSYS Fluent model to simulate the release of tailings from a containment cell located partially above the local ground surface into the nearby streams, and a one-dimensional finite-volume sediment transport model to examine the propagation of a tailings sediment pulse in the river network located downstream. The findings of this investigation aim to assist in estimating the potential impacts that tailings would have if they were transported into rivers and reservoirs located downstream of the Coles Hill deposit that serve as municipal drinking water supplies.

  1. Pathogen Transport and Fate Modeling in the Upper Salem River Watershed Using SWAT Model

    Science.gov (United States)

    SWAT (Soil and Water Assessment Tool) is a dynamic watershed model that is applied to simulate the impact of land management practices on water quality over a continuous period. The Upper Salem River, located in Salem County New Jersey, is listed by the New Jersey Department of ...

  2. 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.

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

    International Nuclear Information System (INIS)

    Kumblad, Linda

    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

  4. Simulation-based model checking approach to cell fate specification during Caenorhabditis elegans vulval development by hybrid functional Petri net with extension

    Directory of Open Access Journals (Sweden)

    Ueno Kazuko

    2009-04-01

    Full Text Available Abstract Background Model checking approaches were applied to biological pathway validations around 2003. Recently, Fisher et al. have proved the importance of model checking approach by inferring new regulation of signaling crosstalk in C. elegans and confirming the regulation with biological experiments. They took a discrete and state-based approach to explore all possible states of the system underlying vulval precursor cell (VPC fate specification for desired properties. However, since both discrete and continuous features appear to be an indispensable part of biological processes, it is more appropriate to use quantitative models to capture the dynamics of biological systems. Our key motivation of this paper is to establish a quantitative methodology to model and analyze in silico models incorporating the use of model checking approach. Results A novel method of modeling and simulating biological systems with the use of model checking approach is proposed based on hybrid functional Petri net with extension (HFPNe as the framework dealing with both discrete and continuous events. Firstly, we construct a quantitative VPC fate model with 1761 components by using HFPNe. Secondly, we employ two major biological fate determination rules – Rule I and Rule II – to VPC fate model. We then conduct 10,000 simulations for each of 48 sets of different genotypes, investigate variations of cell fate patterns under each genotype, and validate the two rules by comparing three simulation targets consisting of fate patterns obtained from in silico and in vivo experiments. In particular, an evaluation was successfully done by using our VPC fate model to investigate one target derived from biological experiments involving hybrid lineage observations. However, the understandings of hybrid lineages are hard to make on a discrete model because the hybrid lineage occurs when the system comes close to certain thresholds as discussed by Sternberg and Horvitz in

  5. The OECD expert meeting on ecotoxicology and environmental fate--towards the development of improved OECD guidelines for the testing of nanomaterials.

    Science.gov (United States)

    Kühnel, Dana; Nickel, Carmen

    2014-02-15

    On behalf of the OECD Working Party on Manufactured Nanomaterials (WPMN) an expert meeting on ecotoxicology and environmental fate of nanomaterials (NMs) took place in January 2013 in Berlin. At this meeting experts from science, industry and regulatory bodies discussed the applicability of OECD test guidelines (TGs) for chemicals to nanomaterials. The objective was to discuss the current state of the relevant science and provide recommendations to the OECD WPMN on (1) the need for updating current OECD TGs and the need for developing new ones specific to nanomaterials; and (2) guidance needed for the appropriate and valid testing of environmental fate and ecotoxicity endpoints for NMs. Experts at the workshop agreed that the majority of the OECD TG for chemicals were generally applicable for the testing of NM, with the exception of TG 105 (water solubility) and 106 (adsorption-desorption). Additionally, the workshop also highlighted considerations when conducting OECD chemical TG on nanomaterials (e.g., sample preparation, dispersion, analysis, dosimetry and characterisation). These considerations will lead to the future development of proposals for new TG and guidance documents (GDs) to ensure that OECD TG give meaningful, repeatable, and accurate results when used for nanomaterials. This report provides a short overview of topics discussed during the meeting and the main outcomes. A more detailed report of the workshop will become available through the OECD, however, due to the urgency of having OECD TG relevant for nanomaterials, this brief report is being shared with the scientific community through this communication. Copyright © 2013. Published by Elsevier B.V.

  6. Modelling the Fate of Ionizable Trace Organic Chemicals from Consumption to Food Crops

    DEFF Research Database (Denmark)

    Polesel, Fabio; Plósz, Benedek G.; Trapp, Stefan

    In this study, we developed and applied a simulation tool to comprehensively predict the fate of three ionizable trace chemicals (triclosan—TCS, furosemide—FUR, ciprofloxacin—CIP) from human consumption/excretion up to the accumulation in wheat, following application of sewage sludge or irrigation...... with river water. Highest translocation to wheat (4.3 μg kgDW-1 in grain) was calculated for FUR, being more significant with irrigation (>45% of emission to soil) than with sludge application (

  7. Fate of polycyclic aromatic hydrocarbons from the North Pacific to the Arctic: Field measurements and fugacity model simulation.

    Science.gov (United States)

    Ke, Hongwei; Chen, Mian; Liu, Mengyang; Chen, Meng; Duan, Mengshan; Huang, Peng; Hong, Jiajun; Lin, Yan; Cheng, Shayen; Wang, Xuran; Huang, Mengxue; Cai, Minggang

    2017-10-01

    Polycyclic aromatic hydrocarbons (PAHs) have accumulated ubiquitously inArctic environments, where re-volatilization of certain organic pollutants as a result of climate change has been observed. To investigate the fate of semivolatile organic compounds in the Arctic, dissolved PAHs in the surface seawaters from the temperate Pacific Ocean to the Arctic Ocean, as well as a water column in the Arctic Ocean, were collected during the 4th Chinese National Arctic Research Expedition in summer 2010. The total concentrations of seven dissolved PAHs in surface water ranged from 1.0 to 5.1 ng L -1 , decreasing with increasing latitude. The vertical profile of PAHs in the Arctic Ocean was generally characteristic of surface enrichment and depth depletion, which emphasized the role of vertical water stratification and particle settling processes. A level III fugacity model was developed in the Bering Sea under steady state assumption. Model results quantitatively simulated the transfer processes and fate of PAHs in the air and water compartments, and highlighted a summer air-to-sea flux of PAHs in the Bering Sea, which meant that the ocean served as a sink for PAHs, at least in summer. Acenaphthylene and acenaphthene reached equilibrium in air-water diffusive exchange, and any perturbation, such as a rise in temperature, might lead to disequilibrium and remobilize these compounds from their Arctic reservoirs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. A first European scale multimedia fate modelling of BDE-209 from 1970 to 2020.

    Science.gov (United States)

    Earnshaw, Mark R; Jones, Kevin C; Sweetman, Andy J

    2015-01-01

    The European Variant Berkeley Trent (EVn-BETR) multimedia fugacity model is used to test the validity of previously derived emission estimates and predict environmental concentrations of the main decabromodiphenyl ether congener, BDE-209. The results are presented here and compared with measured environmental data from the literature. Future multimedia concentration trends are predicted using three emission scenarios (Low, Realistic and High) in the dynamic unsteady state mode covering the period 1970-2020. The spatial and temporal distributions of emissions are evaluated. It is predicted that BDE-209 atmospheric concentrations peaked in 2004 and will decline to negligible levels by 2025. Freshwater concentrations should have peaked in 2011, one year after the emissions peak with sediment concentrations peaking in 2013. Predicted atmospheric concentrations are in good agreement with measured data for the Realistic (best estimate of emissions) and High (worst case scenario) emission scenarios. The Low emission scenario consistently underestimates measured data. The German unilateral ban on the use of DecaBDE in the textile industry is simulated in an additional scenario, the effects of which are mainly observed within Germany with only a small effect on the surrounding areas. Overall, the EVn-BTER model predicts atmospheric concentrations reasonably well, within a factor of 5 and 1.2 for the Realistic and High emission scenarios respectively, providing partial validation for the original emission estimate. Total mean MEC:PEC shows the High emission scenario predicts the best fit between air, freshwater and sediment data. An alternative spatial distribution of emissions is tested, based on higher consumption in EBFRIP member states, resulting in improved agreement between MECs and PECs in comparison with the Uniform spatial distribution based on population density. Despite good agreement between modelled and measured point data, more long-term monitoring datasets are

  9. Proceedings of the international symposium on environmental modeling and radioecology

    International Nuclear Information System (INIS)

    Hisamatsu, Shun'ichi; Ueda, Shinji; Kakiuchi, Hideki; Akata, Naofumi

    2007-03-01

    Environmental models using radioecological parameters are essential for predicting the behavior of radionuclides in the environment. Due to the complex behaviors of radionuclides in the environment, simplified models and parameters with ample margins are used for the safety assessment of nuclear facilities to ensure the safety of people in the surrounding area. As a consequence, radiation exposure doses from the radionuclides have generally been overestimated. Information with more precise predictions of the fate of the radionuclides in the environment and realistic radiation dose estimates are necessary for the public acceptance of nuclear facilities. Realistic dose estimates require continuous improvement of the models and their parameters as well as using state of the art modeling techniques and radioecological knowledge. The first commercial nuclear fuel reprocessing plant in Japan has been built in Rokkasho, Aomori, and the Institute for Environmental Sciences was established for the purpose of assessing the effects of radionuclides released from the plant. Test runs by the plant using actual spent nuclear fuel began in March 2006. With commercial operation soon to begin, there is increasing concern regarding the behavior of radionuclides in the environment. This was a good time to hold a symposium here in Rokkasho to discuss recent progress in the field of environmental modeling and studies of the behaviors of radionuclides in the environment. The exchange of up-to-date information between modelers and experiments was an important aspect of the symposium. The symposium featured 26 oral lectures and 32 poster presentations. The 57 of the presented papers are indexed individually. (J.P.N.)

  10. Modelling the fate of marine debris along a complex shoreline: Lessons from the Great Barrier Reef

    Science.gov (United States)

    Critchell, K.; Grech, A.; Schlaefer, J.; Andutta, F. P.; Lambrechts, J.; Wolanski, E.; Hamann, M.

    2015-12-01

    The accumulation of floating anthropogenic debris in marine and coastal areas has environmental, economic, aesthetic, and human health impacts. Until now, modelling the transport of such debris has largely been restricted to the large-scales of open seas. We used oceanographic modelling to identify potential sites of debris accumulation along a rugged coastline with headlands, islands, rocky coasts and beaches. Our study site was the Great Barrier Reef World Heritage Area that has an emerging problem with debris accumulation. We found that the classical techniques of modelling the transport of floating debris models are only moderately successful due to a number of unknowns or assumptions, such as the value of the wind drift coefficient, the variability of the oceanic forcing and of the wind, the resuspension of some floating debris by waves, and the poorly known relative contribution of floating debris from urban rivers and commercial and recreational shipping. Nevertheless the model was successful in reproducing a number of observations such as the existence of hot spots of accumulation. The orientation of beaches to the prevailing wind direction affected the accumulation rate of debris. The wind drift coefficient and the exact timing of the release of the debris at sea affected little the movement of debris originating from rivers but it affected measurably that of debris originating from ships. It was thus possible to produce local hotspot maps for floating debris, especially those originating from rivers. Such modelling can be used to inform local management decisions, and it also identifies likely priority research areas to more reliably predict the trajectory and landing points of floating debris.

  11. 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.

  12. 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

  13. Behaviour and fate radionuclides in soils. Mathematical modelling and experimental investigations

    International Nuclear Information System (INIS)

    Rovdan, E.N.

    2003-01-01

    The uncontrolled release of radionuclides as result of Chernobyl accident has led to contamination of 23% of territory of Republic of Belarus. Soil has high capacity to adsorb radionuclides and their intensive sorption provides the creation of a long-lived radionuclide source in a terrestrial environment. In the management of the contaminated areas and application of a countermeasure strategy it is extremely important to know the environmental mechanisms governing the behaviour of radionuclides in soils. Basic attention in the work is paid to the study of 137 Cs and 90 Sr because they are the main radionuclides from the view point of radioactive danger in polluted areas. The main features and processes that control radionuclide behaviour in soil have been analysed. On the basis of natural researches, lab test and mathematical modelling the impact of physical-chemical factors and the soil component composition changes upon the radionuclides migration and sorption in natural dispersed systems (peat, sand, bentonite, kaolin, sapropel) has been investigated. The investigations done allowed to substantiate the mathematical models of the radionuclides migration in the regions of positive and negative temperatures, to develop methods of experimental identification of main transfer characteristics and to compile a data base for these models. (orig.)

  14. SimpleTreat: a spreadsheet-based box model to predict the fate of xenobiotics in a municipal waste water treatment plant

    NARCIS (Netherlands)

    Struijs J; van de Meent D; Stoltenkamp J

    1991-01-01

    A non-equilibrium steady state box model is reported, that predicts the fate of new chemicals in a conventional sewage treatment plant from a minimal input data set. The model, written in an electronic spreadsheet (Lotus TM 123), requires a minimum input: some basic properties of the chemical, its

  15. Comparative modeling analyses of Cs-137 fate in the rivers impacted by Chernobyl and Fukushima accidents

    Energy Technology Data Exchange (ETDEWEB)

    Zheleznyak, M.; Kivva, S. [Institute of Environmental Radioactivity, Fukushima University (Japan)

    2014-07-01

    The consequences of two largest nuclear accidents of the last decades - at Chernobyl Nuclear Power Plant (ChNPP) (1986) and at Fukushima Daiichi NPP (FDNPP) (2011) clearly demonstrated that radioactive contamination of water bodies in vicinity of NPP and on the waterways from it, e.g., river- reservoir water after Chernobyl accident and rivers and coastal marine waters after Fukushima accident, in the both cases have been one of the main sources of the public concerns on the accident consequences. The higher weight of water contamination in public perception of the accidents consequences in comparison with the real fraction of doses via aquatic pathways in comparison with other dose components is a specificity of public perception of environmental contamination. This psychological phenomenon that was confirmed after these accidents provides supplementary arguments that the reliable simulation and prediction of the radionuclide dynamics in water and sediments is important part of the post-accidental radioecological research. The purpose of the research is to use the experience of the modeling activities f conducted for the past more than 25 years within the Chernobyl affected Pripyat River and Dnieper River watershed as also data of the new monitoring studies in Japan of Abukuma River (largest in the region - the watershed area is 5400 km{sup 2}), Kuchibuto River, Uta River, Niita River, Natsui River, Same River, as also of the studies on the specific of the 'water-sediment' {sup 137}Cs exchanges in this area to refine the 1-D model RIVTOX and 2-D model COASTOX for the increasing of the predictive power of the modeling technologies. The results of the modeling studies are applied for more accurate prediction of water/sediment radionuclide contamination of rivers and reservoirs in the Fukushima Prefecture and for the comparative analyses of the efficiency of the of the post -accidental measures to diminish the contamination of the water bodies. Document

  16. PATHOGEN TRANSPORT AND FATE MODELING IN THE UPPER SALEM RIVER WATERSHED USING SWAT MODEL - PEER-REVIEWED JOURNAL ARTICLE

    Science.gov (United States)

    Simulation of the fate and transport of pathogen contamination was conducted with SWAT for the Upper Salem River Watershed, located in Salem County, New Jersey. This watershed is 37 km2 and land uses are predominantly agricultural. The watershed drains to a 32 km str...

  17. Environmental Fate and Transport of Poly- and Perfluoroalkyl Substances at Aqueous Film-Forming Foam Impacted Sites

    Science.gov (United States)

    Higgins, C.

    2017-12-01

    Poly and perfluoroalkyl substances (PFASs) are constituents in aqueous film-forming foam (AFFF) used to extinguish fuel fires. Substantially elevated PFAS groundwater concentrations have been observed at firefighter protection training areas, where co-contaminants such as chlorinated solvents and fuel hydrocarbons are also commonly present. Research into the fate and transport potential of PFASs at AFFF-impacted sites will be presented, with a particular focus on how co-contaminants and co-contaminant remediation technologies may alter the composition and transport behavior of PFASs at these sites. A detailed analysis of data collected from a U.S. Air Force site (Ellsworth Air Force Base, South Dakota) indicates that that conversion of polyfluoroalkyl chemicals to perfluoroalkyl acids (PFAAs) in situ due to natural and enhanced remediation of petroleum hydrocarbons. In addition, bench-scale studies examining the effects of various chemical oxidants, typically employed via in situ chemical oxidation (ISCO), indicates that oxidation-based remediation technologies have the potential to alter the release and composition of PFASs in AFFF-impacted source zones. Future challenges in addressing PFAS contamination will be discussed, particularly with respect to closing the mass balance on PFAAs and their precursors at AFFF-impacted sites.

  18. Fate of polybrominated diphenyl ethers during cooking of fish in a new model cooking apparatus and a household microwave.

    Science.gov (United States)

    Bendig, Paul; Hägele, Florian; Blumenstein, Marina; Schmidt, Jasmin; Vetter, Walter

    2013-07-10

    Fish is a major source of human exposure to polybrominated diphenyl ethers (PBDEs). Because fish is mainly consumed after cooking, this measure may alter the pattern and amounts of PBDEs that are finally consumed. To investigate this issue, we developed a model cooking apparatus consisting of a small glass bowl and a beaker glass with an exhaust fitted with a polyurethane foam filter connected to a water jet pump. In this model cooking apparatus, fish (1 g) and/or sunflower oil (0.2/0.4 g) spiked with three PBDE congeners was cooked for 30 min. Small amounts of the semi-volatile PBDEs were evaporated from the fish (BDE-47 cooking apparatus proved to be well-suited to study the fate of polyhalogenated compounds in fish during cooking.

  19. Modelling of migration and fate of selected persistent organic pollutants in the Gulf of Gdansk and the Vistula catchment (Poland): selected results from the EU ELOISE EuroCat project

    Science.gov (United States)

    Zukowska, Barbara; Pacyna, Jozef; Namiesnik, Jacek

    2005-02-01

    The ELOISE EU EuroCat project integrated natural and social sciences to link the impacts affecting the coastal sea to the human activities developed along the catchments. In EuroCat project river catchments' changes and their impact on the inflow area were analysed. The information was linked with environmental models. The part of the EU ELOISE EuroCat project focusing on the Vistula River catchment and the Baltic Sea costal zone was named VisCat. Within the framework of the EU ELOISE EuroCat - VisCat project, CoZMo-POP (Coastal Zone Model for Persistent Organic Pollutants), a non-steady-state multicompartmental mass balance model of long-term chemical fate in the coastal environment or the drainage basin of a large lake environment was used. The model is parameterised and tested herein to simulate the long-term fate and distribution of selected HCHs (hexachlorocyclohexanes) and PCBs (polychlorinated biphenyls) in the Gulf of Gdansk and the Vistula River drainage basin environment. The model can also be used in the future to predict future concentrations in relation to various emission scenarios and in management of economic development and regulations of substance-emission to this environment. However, this would require more extensive efforts in the future on model parameterisation and validation in order to increase the confidence in current model outputs.

  20. Differential local tissue permissiveness influences the final fate of GPR17-expressing oligodendrocyte precursors in two distinct models of demyelination.

    Science.gov (United States)

    Coppolino, Giusy T; Marangon, Davide; Negri, Camilla; Menichetti, Gianluca; Fumagalli, Marta; Gelosa, Paolo; Dimou, Leda; Furlan, Roberto; Lecca, Davide; Abbracchio, Maria P

    2018-05-01

    Promoting remyelination is recognized as a novel strategy to foster repair in neurodegenerative demyelinating diseases, such as multiple sclerosis. In this respect, the receptor GPR17, recently emerged as a new target for remyelination, is expressed by early oligodendrocyte precursors (OPCs) and after a certain differentiation stage it has to be downregulated to allow progression to mature myelinating oligodendrocytes. Here, we took advantage of the first inducible GPR17 reporter mouse line (GPR17-iCreER T2 xCAG-eGFP mice) allowing to follow the final fate of GPR17 + cells by tamoxifen-induced GFP-labeling to unveil the destiny of these cells in two demyelination models: experimental autoimmune encephalomyelitis (EAE), characterized by marked immune cell activation and inflammation, and cuprizone induced demyelination, where myelin dysfunction is achieved by a toxic insult. In both models, demyelination induced a strong increase of fluorescent GFP + cells at damaged areas. However, only in the cuprizone model reacting GFP + cells terminally differentiated to mature oligodendrocytes, thus contributing to remyelination. In EAE, GFP + cells were blocked at immature stages and never became myelinating oligodendrocytes. We suggest these strikingly distinct fates be due to different permissiveness of the local CNS environment. Based on previously reported GPR17 activation by emergency signals (e.g., Stromal Derived Factor-1), we propose that a marked inflammatory milieu, such as that reproduced in EAE, induces GPR17 overactivation resulting in impaired downregulation, untimely and prolonged permanence in OPCs, leading, in turn, to differentiation blockade. Combined treatments with remyelinating agents and anti-inflammatory drugs may represent new potential adequate strategies to halt neurodegeneration and foster recovery. © 2018 The Authors GLIA Published by Wiley Periodicals, Inc.

  1. Modeling fates and impacts for bio-economic analysis of hypothetical oil spill scenarios in San Francisco Bay

    International Nuclear Information System (INIS)

    French McCay, D.; Whittier, N.; Sankaranarayanan, S.; Jennings, J.; Etkin, D.S.

    2002-01-01

    The oil spill risks associated with four submerged rock pinnacles near Alcatraz Island in San Francisco Bay are being evaluated by the United States Army Corps of Engineers. Oil spill modeling has been conducted for a hypothetical oil spill to determine biological impacts, damages to natural resources and response costs. The scenarios are hypothetical vessel grounding on the pinnacles. The SIMAP modeling software by the Applied Science Associates was used to model 3 spill sizes (20, 50 and 95 percentile by volume) and 4 types of oil (gasoline, diesel, heavy fuel oil, and crude oil). The frequency distribution of oil fates and impacts was determined by first running each scenario in stochastic mode. The oil fates and biological effects of the spills were the focus of this paper. It was shown that diesel and crude oil spills would have greater impacts in the water column than heavy fuel or gasoline because gasoline is more volatile and less toxic and because heavy oil spills would be small in volume. It was determined that the major impacts and damage to birds would be low due to the high dilution potential of the bay. It was also noted that dispersants would be very effective in reducing impacts on wildlife and the shoreline. These results are being used to evaluate the cost-benefit analysis of removing the rocks versus the risk of an oil spill. The work demonstrates a statistically quantifiable method to estimate potential impacts that could be used in ecological risk assessment and cost-benefit analysis. 15 refs., 13 tabs., 11 figs

  2. Energy and externality environmental regional model

    International Nuclear Information System (INIS)

    Baldi, L.; Bianchi, A.; Peri, M.

    2000-01-01

    The use of environmental externalities in both territorial management and the direction of energy and environment, faces the difficulties arising from their calculation. The so-called MACBET regional model, which has been constructed for Lombardy, is a first brand new attempt to overcome them. MACBET is a calculation model to assess environmental and employment externalities connected to energy use [it

  3. 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.

  4. Tracing the fate of sulfamethoxazole and its metabolites in subsurface: conceptualization and modelling

    Science.gov (United States)

    Rodriguez-Escales, Paula; Sanchez-Vila, Xavier

    2016-04-01

    The degradation of low adsorptive SMX in subsurface porous media is spatially and temporally variable. It depends on various environmental factors such as in situ redox potential, availability of nutrients, local soil characteristics, and temperature. Its degradation is better under anoxic conditions and by co-metabolism processes. In this work, we first develop a conceptual model of degradation of SMX under different redox conditions (denitrification and iron reducing conditions), characterizing the metabolite formation in each condition, and second, we construct a mathematical model that allows reproducing different experiments of SMX degradation reported in the literature. The model was validated using the experimental data from Barbieri et al. (2012), Nödler et al. (2012) and Mohatt et al. (2011). The model reproduces the reversible degradation of SMX under the presence of nitrous acid as an intermediate product of denitrification (it is the conjugate acid of nitrite), as well as, the metabolite formation (4-nitro-SMX and desamino SMX). In those experiments degradation was mediated by the transient formation of a diazonium cation, which was considered responsible of the substitution of the amine radical by a nitro radical, forming the 4-nitro-SMX. On the other hand, both the diazonium compound and the methanol present in the experiment produced a deamination in the SMX, producing desamino-SMX. The formation of these metabolites was unstable and they were retransformed to SMX. Concerning the iron conditions, SMX was degraded due to the oxidation of iron (Fe2+), which was previously oxidized from goethite due to the degradation of a pool of labile organic carbon. As the oxidation of iron occurred on the goethite surface, the best model to reproduce the SMX reduction was a power law rate. Our work is an attempt to properly formulate the degradation process of an emerging compound considering the real degradation mechanisms, rather than using an upscaled black

  5. A Model Study of the Photochemical Fate of As(III in Paddy-Water

    Directory of Open Access Journals (Sweden)

    Luca Carena

    2017-03-01

    Full Text Available The APEX (Aqueous Photochemistry of Environmentally-occurring Xenobiotics software previously developed by one of us was used to model the photochemistry of As(III in paddy-field water, allowing a comparison with biotic processes. The model included key paddy-water variables, such as the shielding effect of the rice canopy on incident sunlight and its monthly variations, water pH, and the photochemical parameters of the chromophoric dissolved organic matter (CDOM occurring in paddy fields. The half-life times (t1/2 of As(III photooxidation to As(V would be ~20–30 days in May. In contrast, the photochemical oxidation of As(III would be much slower in June and July due to rice-canopy shading of radiation because of plant growth, despite higher sunlight irradiance. At pH < 8 the photooxidation of As(III would mainly be accounted for by reaction with transient species produced by irradiated CDOM (here represented by the excited triplet states 3CDOM*, neglecting the possibly more important reactions with poorly known species such as the phenoxy radicals and, to a lesser extent, with the hydroxyl radicals (HO•. However, the carbonate radicals (CO3•− could be key photooxidants at pH > 8.5 provided that the paddy-water 3CDOM* is sufficiently reactive toward the oxidation of CO32−. In particular, if paddy-water 3CDOM* oxidizes the carbonate anion with a second-order reaction rate constant near (or higher than 106 M−1·s−1, the photooxidation of As(III could be quite fast at pH > 8.5. Such pH conditions can be produced by elevated photosynthetic activity that consumes dissolved CO2.

  6. Single-cell RNA-seq and computational analysis using temporal mixture modelling resolves Th1/Tfh fate bifurcation in malaria.

    Science.gov (United States)

    Lönnberg, Tapio; Svensson, Valentine; James, Kylie R; Fernandez-Ruiz, Daniel; Sebina, Ismail; Montandon, Ruddy; Soon, Megan S F; Fogg, Lily G; Nair, Arya Sheela; Liligeto, Urijah; Stubbington, Michael J T; Ly, Lam-Ha; Bagger, Frederik Otzen; Zwiessele, Max; Lawrence, Neil D; Souza-Fonseca-Guimaraes, Fernando; Bunn, Patrick T; Engwerda, Christian R; Heath, William R; Billker, Oliver; Stegle, Oliver; Haque, Ashraful; Teichmann, Sarah A

    2017-03-03

    Differentiation of naïve CD4 + T cells into functionally distinct T helper subsets is crucial for the orchestration of immune responses. Due to extensive heterogeneity and multiple overlapping transcriptional programs in differentiating T cell populations, this process has remained a challenge for systematic dissection in vivo . By using single-cell transcriptomics and computational analysis using a temporal mixtures of Gaussian processes model, termed GPfates, we reconstructed the developmental trajectories of Th1 and Tfh cells during blood-stage Plasmodium infection in mice. By tracking clonality using endogenous TCR sequences, we first demonstrated that Th1/Tfh bifurcation had occurred at both population and single-clone levels. Next, we identified genes whose expression was associated with Th1 or Tfh fates, and demonstrated a T-cell intrinsic role for Galectin-1 in supporting a Th1 differentiation. We also revealed the close molecular relationship between Th1 and IL-10-producing Tr1 cells in this infection. Th1 and Tfh fates emerged from a highly proliferative precursor that upregulated aerobic glycolysis and accelerated cell cycling as cytokine expression began. Dynamic gene expression of chemokine receptors around bifurcation predicted roles for cell-cell in driving Th1/Tfh fates. In particular, we found that precursor Th cells were coached towards a Th1 but not a Tfh fate by inflammatory monocytes. Thus, by integrating genomic and computational approaches, our study has provided two unique resources, a database www.PlasmoTH.org, which facilitates discovery of novel factors controlling Th1/Tfh fate commitment, and more generally, GPfates, a modelling framework for characterizing cell differentiation towards multiple fates.

  7. Modelling of uranium inputs and its fate in soil; Modellierung von Uraneintraegen aus Duengern und ihr Verbleib im Boden

    Energy Technology Data Exchange (ETDEWEB)

    Achatz, M. [Bundesamt fuer Strahlenschutz, Berlin (Germany); Urso, L. [Bundesamt fuer Strahlenschutz, Oberschleissheim (Germany)

    2016-07-01

    87 % of mineral phosphate fertilizers are produced of sedimentary rock phosphate, which generally contains heavy metals, like uranium. The solution and migration behavior of uranium is apart from its redox ratio, determined by its pH conditions as well as its ligand quality and quantity. A further important role in sorption is played by soil components like clay minerals, pedogenic oxides and soil organic matter. To provide a preferably detailed speciation model of U in soil several physical and chemical components have to be included to be able to state distribution coefficients (k{sub D}) and sorption processes. The model of Hormann and Fischer served as the basis of modelling uranium mobility in soil by using the program PhreeqC. The usage of real soil and soil water measurements may contribute to identify factors and processes influencing the mobility of uranium under preferably realistic conditions. Additionally, the assessment of further predictions towards uranium migration in soil can be made based on a modelling with PhreeqC. The modelling of uranium inputs and its fate in soil can help to elucidate the human caused occurrence or geogenic origin of uranium in soil.

  8. Summer nitrogenous nutrient transport and its fate in the Taiwan Strait: A coupled physical-biological modeling approach

    Science.gov (United States)

    Wang, Jia; Hong, Huasheng; Jiang, Yuwu; Chai, Fei; Yan, Xiao-Hai

    2013-09-01

    In order to understand the fate of nutrients in the Taiwan Strait during summer, we built a coupled physical-biological numerical ocean model, which can capture the basic hydrographic and biological features within the strait. The nutrient that we chose to model is dissolved inorganic nitrogen (DIN). The model includes individual reservoirs for nitrate (NO3) and ammonium (NH4). Both the observational evidence and model results show that NO3 in the strait originates primarily from the upwelling subsurface water in the northern South China Sea (SCS) that enters the strait via the eastern and western routes separated by the Taiwan Bank. The coupled physical and biological effects on the NO3 transport at these two routes are highlighted in the study. For the western route, the shallow topography and the coastal upwelling intensify the biological uptake of NO3 in the whole water column. Consequently, the nitrogenous contribution by this route is mainly in form of the particulate organic nitrogen (PON). In contrast, NO3 is transported conservatively below the nitricline at the deep eastern route, contributing the whole NO3 supply in the TWS. The model estimates the fluxes of DIN and PON into the TWS, from the northern SCS, are 1.8 and 4 kmol s-1, respectively. Over half (˜1 kmol s-1) of the DIN is synthesized into PON by the phytoplankton in the strait. Overall, this study estimates the physical and biological effects on the nutrient transport in the TWS during summer.

  9. Organochlorine pesticides and polychlorinated biphenyls in riverine runoff of the Pearl River Delta, China: Assessment of mass loading, input source and environmental fate

    International Nuclear Information System (INIS)

    Guan Yufeng; Wang Jizhong; Ni Honggang; Zeng, Eddy Y.

    2009-01-01

    A large-scale sampling program was conducted to simultaneously collect water samples at the eight major riverine runoff outlets of the Pearl River Delta (PRD), South China to assess the importance of riverine runoff in transporting anthropogenic pollutants from terrestrial sources to the coastal ocean. The concentrations of Σ 21 OCPs (sum of 21 OCP components) and Σ 20 PCBs (sum of 20 PCB congeners) were 2.57-41.2 and 0.12-1.47 ng/L, respectively. Compositional distributions of DDTs suggested the possibility of new input sources in the study area, but contributions from dicofol seemed considerably low. The annual inputs of Σ 21 OCPs and Σ 20 PCBs were 3090 and 215 kg, with those of total HCHs and DDTs being 1110 and 1020 kg, respectively. A mass balance consideration indicated that riverine runoff is the major mode carrying OCPs from the PRD to the coastal ocean, and the majority of OCPs is further dissipated to open seas. - Mass loadings, input sources and environmental fate of organochlorine pesticides and polychlorinated biphenyls in riverine runoff of the Pearl River Delta, China are assessed

  10. Models in environmental regulatory decision making

    National Research Council Canada - National Science Library

    Committee on Models in the Regulatory Decision Process, National Research Council

    2007-01-01

    .... Models help EPA explain environmental phenomena in settings where direct observations are limited or unavailable, and anticipate the effects of agency policies on the environment, human health and the economy...

  11. Hydrological models for environmental management

    National Research Council Canada - National Science Library

    Bolgov, Mikhail V

    2002-01-01

    .... Stochastic modelling and forecasting cannot at present adequately represent the characteristics of hydrological regimes, nor analyze the influence of water on processes that arise in biological...

  12. Modeling Fate and Transport of Fecal Coliform Bacteria Using SWAT 2005 (Case Study: Jajrood River Watershed, Iran)

    Science.gov (United States)

    Maghrebi, M.; Tajrishy, M.

    2010-12-01

    Jajrood River watershed is one of the main drinking water resources of the capital city of Tehran, Iran. In addition it has been available as many recreational usages especially in the warm months. As a result of being located near one of the crowded cities of the world, a variety of microbial pollutions is commonly perceived in the Jajrood River. Among them, there are strong concerns about fecal coliform bacteria concentration. This article aimed to model fate and transport of fecal coliform bacteria in Jajrood River watershed using Soil and Water Assessment Tool (SWAT) model version 2005. Potential pollutant sources in the study area were detected and quantified for modeling purposes. In spite of being lack of knowledge about bacteria die-off rate in small river bodies, as well as in other watershed-based forms, fecal coliform bacteria die-off rates were estimated using both laboratory and field data investigations with some simplifications. The SWAT model was calibrated over an extended time period (1997-2002) for this watershed. The river flow calibrated using SUFI-2 software and resulted in a very good outputs (R2=0.82, E=0.81). Furthermore SWAT model was validated over January 2003 to September 2005 in the study area and has resulted in good outputs (R2=0.61, E=0.57). This research illustrates SWAT 2005 capability to model fecal coliform bacteria in a populated watershed, and deals with most of watershed microbial pollution sources that are usually observed in developing countries. Fecal coliform concentration simulation results were mostly in the same order in comparison with real data. However, Differences were judged to be related to lack of input data. In this article different aspects of SWAT capabilities for modeling of fecal coliform bacteria concentration will be reviewed and it will present new insights in bacteria modeling procedures especially for mountainous, high populated and small sized watersheds.

  13. Modeling reveals bistability and low-pass filtering in the network module determining blood stem cell fate.

    Directory of Open Access Journals (Sweden)

    Jatin Narula

    2010-05-01

    Full Text Available Combinatorial regulation of gene expression is ubiquitous in eukaryotes with multiple inputs converging on regulatory control elements. The dynamic properties of these elements determine the functionality of genetic networks regulating differentiation and development. Here we propose a method to quantitatively characterize the regulatory output of distant enhancers with a biophysical approach that recursively determines free energies of protein-protein and protein-DNA interactions from experimental analysis of transcriptional reporter libraries. We apply this method to model the Scl-Gata2-Fli1 triad-a network module important for cell fate specification of hematopoietic stem cells. We show that this triad module is inherently bistable with irreversible transitions in response to physiologically relevant signals such as Notch, Bmp4 and Gata1 and we use the model to predict the sensitivity of the network to mutations. We also show that the triad acts as a low-pass filter by switching between steady states only in response to signals that persist for longer than a minimum duration threshold. We have found that the auto-regulation loops connecting the slow-degrading Scl to Gata2 and Fli1 are crucial for this low-pass filtering property. Taken together our analysis not only reveals new insights into hematopoietic stem cell regulatory network functionality but also provides a novel and widely applicable strategy to incorporate experimental measurements into dynamical network models.

  14. The environmental behavior and chemical fate of energetic compounds (TNT, RDX, tetryl) in soil and plant systems

    International Nuclear Information System (INIS)

    Cataldo, D.A.; Harvey, S.D.; Fellows, R.J.

    1993-06-01

    Munitions materials can accumulate or cycle in terrestrial environs at production and manufacturing facilities and thus pose potential heath and environmental concerns. To address questions related to food chain accumulation, the environmental behavior of energetic compounds (2,4,6-trinitrotoluene,TNT; hexahydro-1,3,5-trinitro-1,3,5-triazine, RDX; 2,4,6-trinitrophenylmethylnitramine, tetryl) was evaluated. Emphasis was placed on determining the potential for soil/plant transfer of munitions residues, translocation and distribution within the plant, the extent to which compounds were metabolized following accumulation, and the chemical nature and form of accumulated residues. Both TNT and tetryl undergo extensive chemical transformation in soil, forming aminodinitrotoluene isomers and N-methyl-2,4,6-trinitroaniline residues, respectively, along with a series of unknowns. After 60 days, only 30% of the amended TNT and 8% of the amended tetryl remained unchanged in the soil. In contrast, 78% of the soil-amended RDX remained unchanged after 60 days. After 60 days, plants grown in soils containing 10 ppm residues contained from 5 μg TNT/g to 600 μg RDX/G fresh wt. tissue. TNT and tetryl residues were primarily accumulated in roots (75%), while RDX was concentrated in leaves and seed. The principal transport form for TNT (root to shoot) was an acid labile conjugate of aminodinitrotoluene; RDX was transported unchanged. On accumulation in roots and leaves, highly polar and non-extractable TNT metabolites dominated, with the aminodinitrotoluene isomers accounting for less than 20% of the residues present. Only a few percent were present as the parent TNT. RDX was partitioned similarly to TNT, with 8 to 30% of the RDX appearing as polar metabolites, 20--50% as parent RDX, and the balance as non-extractable residues. Tetryl was metabolized to N-methyl-2,4,6-trinitroaniline and a variety of polar metabolites

  15. Environmental risk assessment of selected organic chemicals based on TOC test and QSAR estimation models.

    Science.gov (United States)

    Chi, Yulang; Zhang, Huanteng; Huang, Qiansheng; Lin, Yi; Ye, Guozhu; Zhu, Huimin; Dong, Sijun

    2018-02-01

    Environmental risks of organic chemicals have been greatly determined by their persistence, bioaccumulation, and toxicity (PBT) and physicochemical properties. Major regulations in different countries and regions identify chemicals according to their bioconcentration factor (BCF) and octanol-water partition coefficient (Kow), which frequently displays a substantial correlation with the sediment sorption coefficient (Koc). Half-life or degradability is crucial for the persistence evaluation of chemicals. Quantitative structure activity relationship (QSAR) estimation models are indispensable for predicting environmental fate and health effects in the absence of field- or laboratory-based data. In this study, 39 chemicals of high concern were chosen for half-life testing based on total organic carbon (TOC) degradation, and two widely accepted and highly used QSAR estimation models (i.e., EPI Suite and PBT Profiler) were adopted for environmental risk evaluation. The experimental results and estimated data, as well as the two model-based results were compared, based on the water solubility, Kow, Koc, BCF and half-life. Environmental risk assessment of the selected compounds was achieved by combining experimental data and estimation models. It was concluded that both EPI Suite and PBT Profiler were fairly accurate in measuring the physicochemical properties and degradation half-lives for water, soil, and sediment. However, the half-lives between the experimental and the estimated results were still not absolutely consistent. This suggests deficiencies of the prediction models in some ways, and the necessity to combine the experimental data and predicted results for the evaluation of environmental fate and risks of pollutants. Copyright © 2016. Published by Elsevier B.V.

  16. Groundwater Impacts of Radioactive Wastes and Associated Environmental Modeling Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Rui; Zheng, Chunmiao; Liu, Chongxuan

    2012-11-01

    This article provides a review of the major sources of radioactive wastes and their impacts on groundwater contamination. The review discusses the major biogeochemical processes that control the transport and fate of radionuclide contaminants in groundwater, and describe the evolution of mathematical models designed to simulate and assess the transport and transformation of radionuclides in groundwater.

  17. The potential use of Chernobyl fallout data to test and evaluate the predictions of environmental radiological assessment models

    International Nuclear Information System (INIS)

    Richmond, C.R.; Hoffman, F.O.; Blaylock, B.G.; Eckerman, K.F.; Lesslie, P.A.; Miller, C.W.; Ng, Y.C.; Till, J.E.

    1988-06-01

    The objectives of the Model Validation Committee were to collaborate with US and foreign scientists to collect, manage, and evaluate data for identifying critical research issues and data needs to support an integrated assessment of the Chernobyl nuclear accident; test environmental transport, human dosimetric, and health effects models against measured data to determine their efficacy in guiding decisions on protective actions and in estimating exposures to populations and individuals following a nuclear accident; and apply Chernobyl data to quantifications of key processes governing the environmental transport, fate and effects of radionuclides and other trace substances. 55 refs

  18. Modelling environmental dynamics. Advances in goematic solutions

    Energy Technology Data Exchange (ETDEWEB)

    Paegelow, Martin [Toulouse-2 Univ., 31 (France). GEODE UMR 5602 CNRS; Camacho Olmedo, Maria Teresa (eds.) [Granada Univ (Spain). Dpto. de Analisis Geografico Regional y Geografia Fisica

    2008-07-01

    Modelling environmental dynamics is critical to understanding and predicting the evolution of the environment in response to the large number of influences including urbanisation, climate change and deforestation. Simulation and modelling provide support for decision making in environmental management. The first chapter introduces terminology and provides an overview of methodological modelling approaches which may be applied to environmental and complex dynamics. Based on this introduction this book illustrates various models applied to a large variety of themes: deforestation in tropical regions, fire risk, natural reforestation in European mountains, agriculture, biodiversity, urbanism, climate change and land management for decision support, etc. These case studies, provided by a large international spectrum of researchers and presented in a uniform structure, focus particularly on methods and model validation so that this book is not only aimed at researchers and graduates but also at professionals. (orig.)

  19. A unified framework for modelling sediment fate from source to sink and its interactions with reef systems over geological times.

    Science.gov (United States)

    Salles, Tristan; Ding, Xuesong; Webster, Jody M; Vila-Concejo, Ana; Brocard, Gilles; Pall, Jodie

    2018-03-27

    Understanding the effects of climatic variability on sediment dynamics is hindered by limited ability of current models to simulate long-term evolution of sediment transfer from source to sink and associated morphological changes. We present a new approach based on a reduced-complexity model which computes over geological time: sediment transport from landmasses to coasts, reworking of marine sediments by longshore currents, and development of coral reef systems. Our framework links together the main sedimentary processes driving mixed siliciclastic-carbonate system dynamics. It offers a methodology for objective and quantitative sediment fate estimations over regional and millennial time-scales. A simulation of the Holocene evolution of the Great Barrier Reef shows: (1) how high sediment loads from catchments erosion prevented coral growth during the early transgression phase and favoured sediment gravity-flows in the deepest parts of the northern region basin floor (prior to 8 ka before present (BP)); (2) how the fine balance between climate, sea-level, and margin physiography enabled coral reefs to thrive under limited shelf sedimentation rates after ~6 ka BP; and, (3) how since 3 ka BP, with the decrease of accommodation space, reduced of vertical growth led to the lateral extension of reefs consistent with available observational data.

  20. Impact of multi-layer soil model on the simulation of persistent organic pollutant fate at european scale

    International Nuclear Information System (INIS)

    Loizeau, Vincent

    2014-01-01

    Persistent Organic Pollutants (POPs) are toxic substances that bio-accumulate in the food chain. Once emitted in the atmosphere, they are transported by the wind and deposited on soil. Since they are persistent, they can be re-emitted from soil to atmosphere by volatilization and travel over very long distances. This process is called grasshopper effect. Thus, POPs may be found at significant levels far from their emission source. It is necessary to understand the transport and fate of these pollutants in order to support the decision making process and reduce human exposure to POPs. Regulations over the last decades lead to a decrease of anthropogenic emissions and subsequent decrease of atmospheric concentration. In this context, the soil is no longer a sink of POPs but can be a source to the atmosphere. Many numeric models aim to study the behavior of POPs in the environment. Most of them consider soil compartment as a homogeneous box, leading to an underestimation of re-emissions. Then, it appears of great importance to develop more realistic soil models. The objective of my thesis was to develop such a model, with vertical transport within the soil. This model was evaluated against measured concentration soil profile. We also conducted a sensitivity analysis to identify the key parameters involved in the process of re-emissions. Then, the soil model was coupled with an atmospheric transport model. A case study was finally undertaken to estimate the impacts of re-emissions on global-mass balance of POPs at European scale. (author) [fr

  1. The integrated environmental control model

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, E.S.; Berkenpas, M.B.; Kalagnanam, J.R. [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    1995-11-01

    The capability to estimate the performance and cost of emission control systems is critical to a variety of planning and analysis requirements faced by utilities, regulators, researchers and analysts in the public and private sectors. The computer model described in this paper has been developed for DOe to provide an up-to-date capability for analyzing a variety of pre-combustion, combustion, and post-combustion options in an integrated framework. A unique capability allows performance and costs to be modeled probabilistically, which allows explicit characterization of uncertainties and risks.

  2. Polybrominated diphenyl ethers fate in China: a review with an emphasis on environmental contamination levels, human exposure and regulation.

    Science.gov (United States)

    Chen, Yuan; Li, Jinhui; Liu, Lili; Zhao, Nana

    2012-12-30

    Because of their highly effective flame-retardant capability, polybrominated diphenyl ethers (PBDEs) have been extensively used as flame retardants in consumer goods. However, compelling evidence shows that many congeners of PBDEs have been accumulating in the environment, in biota and in human populations worldwide. In China, although octabrominated diphenyl ether (octaBDE) has never been produced or used, pentabrominated diphenyl ether (pentaBDE) and decabrominated diphenyl ether (decaBDE) have been produced and used in large quantities. In the face of increasing evidence about PBDE pollution and the adoption of international conventions, there is a growing push for China to develop more stringent methods of managing PBDE waste. This paper summarizes the information about PBDE production and application, describes the flame-retarding mechanism, and then reviews the toxicity and levels of PBDEs in China's environmental media and human tissues. Based on international regulations on PBDEs, the paper finally puts forward some suggestions for Chinese policy making and for self-regulation within the flame retardant industry. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. An overview of chemical additives present in plastics: Migration, release, fate and environmental impact during their use, disposal and recycling.

    Science.gov (United States)

    Hahladakis, John N; Velis, Costas A; Weber, Roland; Iacovidou, Eleni; Purnell, Phil

    2018-02-15

    Over the last 60 years plastics production has increased manifold, owing to their inexpensive, multipurpose, durable and lightweight nature. These characteristics have raised the demand for plastic materials that will continue to grow over the coming years. However, with increased plastic materials production, comes increased plastic material wastage creating a number of challenges, as well as opportunities to the waste management industry. The present overview highlights the waste management and pollution challenges, emphasising on the various chemical substances (known as "additives") contained in all plastic products for enhancing polymer properties and prolonging their life. Despite how useful these additives are in the functionality of polymer products, their potential to contaminate soil, air, water and food is widely documented in literature and described herein. These additives can potentially migrate and undesirably lead to human exposure via e.g. food contact materials, such as packaging. They can, also, be released from plastics during the various recycling and recovery processes and from the products produced from recyclates. Thus, sound recycling has to be performed in such a way as to ensure that emission of substances of high concern and contamination of recycled products is avoided, ensuring environmental and human health protection, at all times. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  4. Predictions of models for environmental radiological assessment

    International Nuclear Information System (INIS)

    Peres, Sueli da Silva; Lauria, Dejanira da Costa; Mahler, Claudio Fernando

    2011-01-01

    In the field of environmental impact assessment, models are used for estimating source term, environmental dispersion and transfer of radionuclides, exposure pathway, radiation dose and the risk for human beings Although it is recognized that the specific information of local data are important to improve the quality of the dose assessment results, in fact obtaining it can be very difficult and expensive. Sources of uncertainties are numerous, among which we can cite: the subjectivity of modelers, exposure scenarios and pathways, used codes and general parameters. The various models available utilize different mathematical approaches with different complexities that can result in different predictions. Thus, for the same inputs different models can produce very different outputs. This paper presents briefly the main advances in the field of environmental radiological assessment that aim to improve the reliability of the models used in the assessment of environmental radiological impact. The intercomparison exercise of model supplied incompatible results for 137 Cs and 60 Co, enhancing the need for developing reference methodologies for environmental radiological assessment that allow to confront dose estimations in a common comparison base. The results of the intercomparison exercise are present briefly. (author)

  5. Toxicological Impacts of Pharmaceuticals and Personal Care Products on Water Quality: Environmental Fate, Transformation and Health Effects

    Science.gov (United States)

    Rubasinghege, G. R. S.; Rijal, H.; Gurung, R.; Maldonado-Torres, S.; Rogelj, S.; Piyasena, M.

    2016-12-01

    The growing medical and personal needs of the human population have escalated release of pharmaceuticals and personal care products (PPCPs) to the nature. The current work investigated abiotic degradation pathways of selected PPCPs in the presence of major mineral components of soil and the acute health effects of degraded PPCPs. Degradation of selected PPCPs (ibuprofen and clofibric acid) was carried out using custom-built glass reactors in batch studies. The secondary products of PPCPs were analyzed and identified using modified HPLC and LC-MS methods. Results from these studies showed that the extent of degradation depends on the type of the clay or mineral oxide, and solar radiation. In the absence of solar radiation (night time chemistry), the dominant reaction mechanism was observed to be the adsorption of PPCPs on to clay particles where surface functional groups and particle size play a key role. In contrast, under solar radiation, PPCPs break down to several fractions in the presence of clay particles. The decay rates were at least 3-fold higher for irradiated samples compared to that of dark conditions. Acute toxicity of selected PPCPs and their degradation products were tested on three microorganisms: gram-positive soil bacteria, Bacillus megaterium; gram-negative marine bacteria, Pseudoaltermonas atlantica; and algae from the Chlorella genus. Growth inhibition was measured using optical density measurements, MTT viability assay, and flow cytometer. The results suggest that the concentrations of primary compounds, Ibuprofen and Clofibric Acid, found in the environment that ranges from μg/L to ng/L are not sufficient to inhibit growth of either three microorganisms. However, selected organisms showed significant differences in sensitivity to degraded products. Results from current work advance our knowledge and understanding in the fields of environmental toxicology, chemistry in aqueous phases, and geochemistry.

  6. Source-Flux-Fate Modelling of Priority Pollutants in Stormwater Systems

    DEFF Research Database (Denmark)

    Vezzaro, Luca

    quality management. The thesis provides a framework for the trustworthy application of models to estimate PP fluxes from their sources, and through stormwater drainage systems, and to the sink. This fills a knowledge gap regarding stormwater PP and it supplies urban water managers with modelling tools......The increasing focus on management of stormwater Priority Pollutants (PP) enhances the role of mathematical models as support for the assessment of stormwater quality control strategies. This thesis investigates and presents modelling approaches that are suitable to simulate PP fluxes across...... stormwater systems, supporting the development of pollution control strategies. This is obtained by analyzing four study areas: (i) catchment characterization, (ii) pollutant release and transport models, (iii) stormwater treatment models, and (iv) combination of the above into an integrated model. Given...

  7. Using model-based screening to help discover unknown environmental contaminants.

    Science.gov (United States)

    McLachlan, Michael S; Kierkegaard, Amelie; Radke, Michael; Sobek, Anna; Malmvärn, Anna; Alsberg, Tomas; Arnot, Jon A; Brown, Trevor N; Wania, Frank; Breivik, Knut; Xu, Shihe

    2014-07-01

    Of the tens of thousands of chemicals in use, only a small fraction have been analyzed in environmental samples. To effectively identify environmental contaminants, methods to prioritize chemicals for analytical method development are required. We used a high-throughput model of chemical emissions, fate, and bioaccumulation to identify chemicals likely to have high concentrations in specific environmental media, and we prioritized these for target analysis. This model-based screening was applied to 215 organosilicon chemicals culled from industrial chemical production statistics. The model-based screening prioritized several recognized organosilicon contaminants and generated hypotheses leading to the selection of three chemicals that have not previously been identified as potential environmental contaminants for target analysis. Trace analytical methods were developed, and the chemicals were analyzed in air, sewage sludge, and sediment. All three substances were found to be environmental contaminants. Phenyl-tris(trimethylsiloxy)silane was present in all samples analyzed, with concentrations of ∼50 pg m(-3) in Stockholm air and ∼0.5 ng g(-1) dw in sediment from the Stockholm archipelago. Tris(trifluoropropyl)trimethyl-cyclotrisiloxane and tetrakis(trifluoropropyl)tetramethyl-cyclotetrasiloxane were found in sediments from Lake Mjøsa at ∼1 ng g(-1) dw. The discovery of three novel environmental contaminants shows that models can be useful for prioritizing chemicals for exploratory assessment.

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

    International Nuclear Information System (INIS)

    Erichsen, Anders Christian; Moehlenberg, Flemming; Closter, Rikke Margrethe; Sandberg, Johannes

    2010-06-01

    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

  9. 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 quasi

  10. Continuous-time modeling of cell fate determination in Arabidopsis flowers

    Directory of Open Access Journals (Sweden)

    Angenent Gerco C

    2010-07-01

    Full Text Available Abstract Background The genetic control of floral organ specification is currently being investigated by various approaches, both experimentally and through modeling. Models and simulations have mostly involved boolean or related methods, and so far a quantitative, continuous-time approach has not been explored. Results We propose an ordinary differential equation (ODE model that describes the gene expression dynamics of a gene regulatory network that controls floral organ formation in the model plant Arabidopsis thaliana. In this model, the dimerization of MADS-box transcription factors is incorporated explicitly. The unknown parameters are estimated from (known experimental expression data. The model is validated by simulation studies of known mutant plants. Conclusions The proposed model gives realistic predictions with respect to independent mutation data. A simulation study is carried out to predict the effects of a new type of mutation that has so far not been made in Arabidopsis, but that could be used as a severe test of the validity of the model. According to our predictions, the role of dimers is surprisingly important. Moreover, the functional loss of any dimer leads to one or more phenotypic alterations.

  11. A model based on soil structural aspects describing the fate of genetically modified bacteria in soil

    NARCIS (Netherlands)

    Hoeven, van der N.; Elsas, van J.D.; Heijnen, C.E.

    1996-01-01

    A computer simulation model was developed which describes growth and competition of bacteria in the soil environment. In the model, soil was assumed to contain millions of pores of a few different size classes. An introduced bacterial strain, e.g. a genetically modified micro-organism (GEMMO), was

  12. Pesticide fate at regional scale: Development of an integrated model approach and application

    Science.gov (United States)

    Herbst, M.; Hardelauf, H.; Harms, R.; Vanderborght, J.; Vereecken, H.

    As a result of agricultural practice many soils and aquifers are contaminated with pesticides. In order to quantify the side-effects of these anthropogenic impacts on groundwater quality at regional scale, a process-based, integrated model approach was developed. The Richards’ equation based numerical model TRACE calculates the three-dimensional saturated/unsaturated water flow. For the modeling of regional scale pesticide transport we linked TRACE with the plant module SUCROS and with 3DLEWASTE, a hybrid Lagrangian/Eulerian approach to solve the convection/dispersion equation. We used measurements, standard methods like pedotransfer-functions or parameters from literature to derive the model input for the process model. A first-step application of TRACE/3DLEWASTE to the 20 km 2 test area ‘Zwischenscholle’ for the period 1983-1993 reveals the behaviour of the pesticide isoproturon. The selected test area is characterised by an intense agricultural use and shallow groundwater, resulting in a high vulnerability of the groundwater to pesticide contamination. The model results stress the importance of the unsaturated zone for the occurrence of pesticides in groundwater. Remarkable isoproturon concentrations in groundwater are predicted for locations with thin layered and permeable soils. For four selected locations we used measured piezometric heads to validate predicted groundwater levels. In general, the model results are consistent and reasonable. Thus the developed integrated model approach is seen as a promising tool for the quantification of the agricultural practice impact on groundwater quality.

  13. Monitoring and modeling the fate of commonly used pesticides in surface water of the Lower Mekong Delta

    Science.gov (United States)

    van Toan, Pham; Sebesvari, Zita; Loan, Vo Phuong Hong; Renaud, Fabrice

    2010-05-01

    Introduction: The Lower Mekong Delta, one of the largest agricultural areas in Southeast Asia, has been reported to be increasingly polluted by agrochemicals since the beginning of the transformation processes in Vietnamese economy and specifically in the agricultural sector in 1986 (MRCS, 2007; Dasgupta et al., 2005; Dung, 2003; Phuong, 2003). Although pesticides have contributed significantly to enhancing agricultural productivity, these agrochemicals also have created risks to human health and environment (Margni, 2001; Phuong, 2003; Dasgupta et al., 2005) and lead to value loss of water resources (Phuong, 2003). While prohibited persistent organic pollutants such as HCHs and DDTs, were monitored and still detected in the Lower Mekong Delta in recent studies (Minh et al., 2007, Carvalho et al., 2008) little data exist on water pollution by recently used pesticides in the Delta. Aiming to fill this information gap, a study comprising three components was set up at two study sites of the Delta. Pesticide use and management was investigated through surveys and participatory rural appraisals with farmers; pesticide residue concentrations were determined in field outflows, connected irrigation canals and in drinking water and finally pesticide fate was predicted by using a coupled MIKE 11/ MIKE SHE model. This abstract focuses on the work done in the field of pesticide monitoring. The western study site (An Long Commune, Dong Thap province) represented an agricultural pattern with two intensive paddy rice crops per year and was heavily affected by flood in the rainy season. The second site located in the central part of the Delta (Ba Lang ward, Can Tho City) was characterized by a mix of paddy rice, vegetables and fruit trees. Fifteen pesticide compounds (buprofezin, butachlor, cypermethrin, difenozonazol, α-endosulfan, β-endosulfan, endosulfan-sulfate, fenobucarb, fipronil, hexaconazol, isoprothiolane, pretilachlor, profenofos, propanil, and propiconazol) were

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

    Science.gov (United States)

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

    2016-12-01

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

  15. Fully in Silico Calibration of Empirical Predictive Models for Environmental Fate Properties of Novel Munitions Compounds

    Science.gov (United States)

    2016-04-01

    constants using several IMC related aromatic amines. To develop QSARs with these data, many possible descriptors were evaluated , ranging from simple to...converted to approximate half-lives to give. The blue symbols are experimental data, obtained with IMC related amino compounds...calibrated “in silico” that predict the hydrolysis behavior of the diverse range of energetic NACs. However, new experimental and computational

  16. 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

  17. Modelling the fate of hydrophobic organic contaminants in a boreal forest catchment: A cross disciplinary approach to assessing diffuse pollution to surface waters

    International Nuclear Information System (INIS)

    Bergknut, Magnus; Meijer, Sandra; Halsall, Crispin; Agren, Anneli; Laudon, Hjalmar; Koehler, Stephan; Jones, Kevin C.; Tysklind, Mats; Wiberg, Karin

    2010-01-01

    The fate of hydrophobic organic compounds (HOCs) in soils and waters in a northern boreal catchment was explored through the development of a chemical fate model in a well-characterised catchment system dominated by two land types: forest and mire. Input was based solely on atmospheric deposition, dominated by accumulation in the winter snowpack. Release from soils was governed by the HOC concentration in soil, the soil organic carbon fraction and soil-water DOC content. The modelled export of selected HOCs in surface waters ranged between 11 and 250 ng day -1 during the snow covered period, compared to 200 and 9600 ng/d during snow-melt; highlighting the importance of the snow pack as a source of these chemicals. The predicted levels of HOCs in surface water were in reasonable agreement to a limited set of measured values, although the model tended to over predict concentrations of HOCs for the forested sub-catchment, by over an order of magnitude in the case of hexachlorobenzene and PCB 180. This possibly reflects both the heterogeneity of the forest soils and the complicated and changing hydrology experienced between the different seasons. - The fate of hydrophobic organic contaminants in a boreal forest catchment is connected to the flux of dissolved organic carbon and seasonal deposition.

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

    NARCIS (Netherlands)

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

    2016-01-01

    There is a growing need for good environmental risk assessment of engineered nanoparticles (ENPs). Environmental risk assessment of ENPs has been hampered by lack of data and knowledge about ENPs, their environmental fate, and their toxicity. This leads to uncertainty in the risk assessment. To

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

    NARCIS (Netherlands)

    Jacobs, R.; Meesters, J.A.J.; Ter Braak, C.J.; Meent, D. van de; van der Voet, H.

    2016-01-01

    There is a growing need for good environmental risk assessment of engineered nanoparticles (ENPs). Environmental risk assessment of ENPs has been hampered by lack of data and knowledge about ENPs, their environmental fate, and their toxicity. This leads to uncertainty in the risk assessment. To deal

  20. Modelling Illicit Drug Fate in Sewers for Wastewater-Based Epidemiology

    DEFF Research Database (Denmark)

    Ramin, Pedram

    was found during festival period as compared to normal weekdays. Wastewater-based epidemiology is a truly interdisciplinary approach in which engineering tools, including models developed and tested in this thesis, can be beneficial for the accurate estimation of drug consumption in urban areas........ Sewer systems can be considered as biological reactors, in which the concentration of organic chemicals present in wastewater can be impacted by in-sewer processes during hydraulic residence time. Illicit drug biomarkers, as trace organic chemicals in the range of nanograms to micrograms per liter...... on sorption and transformation of drug biomarkers in raw wastewater and sewer biofilms; and (ii) developing modelling tools – by combining and extending existing modelling frameworks – to predict such processes. To achieve this goal, a substantial part of this thesis was dedicated to the experimental...

  1. Comparison of three pesticide fate models for two herbicides leaching under field conditions in a maize cropping system

    Science.gov (United States)

    Marin-Benito, Jesus Maria; Pot, Valérie; Alletto, Lionel; Mamy, Laure; Bedos, Carole; van den Berg, Erik; Barriuso, Enrique; Benoit, Pierre

    2014-05-01

    Losses of pesticides from agricultural soils may influence the quality of groundwater. Therefore, numerous models were developed to assess the transfer of pesticides from the soil surface to groundwater after their application to an agricultural field. Our objective was thus to compare the ability of three pesticide fate models to describe the behavior of water, and S-metolachlor (SMOC) and mesotrione (MES) herbicides as observed under field conditions in a maize monoculture system. Simulations were based on field experimentations set up in Toulouse area (France). The tested scenario focused on a conventional maize monoculture and included two irrigated cropping periods with a fallow period managed with bare soil. SMOC was sprayed annually at 1.25 and 1.52 kg a.i./ha in 2011 and 2012, respectively, while MES was only applied in 2012 but twice, at 0.150 kg a.i./ha. Simulations were performed with the PRZM, PEARL and MACRO models parameterized with field, laboratory, and literature data, and pedotransfer functions. The results of simulations were compared with soil tension, water content and percolation data monitored at different depths in 2011-2012. The comparison of the results obtained by the three models indicated that PRZM was not able to simulate properly the water dynamic in the soil profile and for example, it predicted that microporosity was always saturated at 1 m-depth. On the contrary, PEARL and MACRO simulated quite well the observed water behavior (water pressure head and volumetric water content) at 20 and 50 cm-depth during the irrigated cropping period of 2012. However, simulated soil moisture and water pressure were overestimated before the rainfall event of 20 May 2012. MACRO and PEARL simulations generally showed similar water flow dynamics for the whole period at the three depths. Neither the dynamic nor the total amount of percolated water was correctly simulated by any model. The three models overestimated the total water volume leached at 1 m

  2. Mathematical Modeling of Fate and Transport of Aqueous Species in Stormflow Entering Infiltration Basin.

    Science.gov (United States)

    Massoudieh, A.; Sengor, S. S.; Meyer, S.; Ginn, T. R.

    2004-12-01

    The State of California is evaluating the role of passive stormwater detention facilities for the purpose of attenuating potential dissolved and suspended chemical species that may originate in roadway runoff of rainfall. The engineering design of such infiltration basins requires tools to quantify their performance as recipients of stormwater runoff from roadways, and as filters of aqueous chemical species. For this purpose a one-dimensional unsaturated flow and transport model is developed to estimate the efficiency of storm-water infiltration basins in treating roadway generated metallic and organic pollutants. Kinematic wave approximation is used along with van Genuchten water retention model to simulate water percolation thorough the infiltration basin. For metals a Langmuir type nonlinear competitive sorption isotherm is used for transport of chemicals and a kinetic reversible linear sorption model is considered for organics. The model is applied to known roadway born metallic contaminations such as copper, zinc, lead, chromium, nickel and cadmium, as well as organic species such as diazinon, diuron, ghlyphosate and pyrene, for several representative soil and precipitation condition for California within a period of five years. Representative soil parameters and precipitation patterns are extracted from frequency distributions extracted from a recent study. In addition sensitivity analysis has been done to evaluate the effect of soil property values on the performance of infiltration basins. The results can be used to evaluate the performance of infiltration basins in improving the water quality as well as being used in providing guidelines in design and maintenance of infiltration basins.

  3. 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)

    Kumblad, L.

    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 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 -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

  4. 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

  5. Community Environmental Education as a Model for Effective Environmental Programmes

    Science.gov (United States)

    Blair, Morag

    2008-01-01

    The benefits of community environmental education outlined in environmental education literature are supported by the findings and implications of a research study undertaken in New Zealand. Evidence from a two-case case study suggests that environmental programmes guided by the key principles and practices of community environmental education,…

  6. International Summit on Integrated Environmental Modeling

    Science.gov (United States)

    This report describes the International Summit on Integrated Environmental Modeling (IEM), held in Washington, DC 7th-9th December 2010. The meeting brought together 57 scientists and managers from leading US and European government and non-governmental organizations, universitie...

  7. Model comparisons and genetic and environmental parameter ...

    African Journals Online (AJOL)

    arc

    Model comparisons and genetic and environmental parameter estimates of growth and the ... breeding strategies and for accurate breeding value estimation. The objectives ...... Sci. 23, 72-76. Van Wyk, J.B., Fair, M.D. & Cloete, S.W.P., 2003.

  8. Fate of bone marrow mesenchymal stromal cells following autologous transplantation in a rabbit model of osteonecrosis.

    Science.gov (United States)

    Sugaya, Hisashi; Mishima, Hajime; Gao, Ran; Kaul, Sunil C; Wadhwa, Renu; Aoto, Katsuya; Li, Meihua; Yoshioka, Tomokazu; Ogawa, Takeshi; Ochiai, Naoyuki; Yamazaki, Masashi

    2016-02-01

    Internalizing quantum dots (i-QDs) are a useful tool for tracking cells in vivo in models of tissue regeneration. We previously synthesized i-QDs by conjugating QDs with a unique internalizing antibody against a heat shock protein 70 family stress chaperone. In the present study, i-QDs were used to label rabbit mesenchymal stromal cells (MSCs) that were then transplanted into rabbits to assess differentiation potential in an osteonecrosis model. The i-QDs were taken up by bone marrow-derived MSCs collected from the iliac of 12-week-old Japanese white rabbits that were positive for cluster of differentiation (CD)81 and negative for CD34 and human leukocyte antigen DR. The average rate of i-QD internalization was 93.3%. At 4, 8, 12, and 24 weeks after transplantation, tissue repair was evaluated histologically and by epifluorescence and electron microscopy. The i-QDs were detected at the margins of the drill holes and in the necrotized bone trabecular. There was significant colocalization of the i-QD signal in transplanted cells and markers of osteoblast and mineralization at 4, 8, and 12 weeks post-transplantation, while i-QDs were detected in areas of mineralization at 12 and 24 weeks post-transplantation. Moreover, i-QDs were observed in osteoblasts in regenerated tissue by electron microscopy, demonstrating that the tissue was derived from transplanted cells. These results indicate that transplanted MSCs can differentiate into osteoblasts and induce tissue repair in an osteonecrosis model and can be tracked over the long term by i-QD labeling. Copyright © 2015 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  9. CASCADER: An m-chain gas-phase radionuclide transport and fate model

    International Nuclear Information System (INIS)

    Cawlfield, D.E.; Been, K.B.; Emer, D.F.; Lindstrom, F.T.; Shott, G.J.

    1993-06-01

    Chemicals and radionuclides move either in the gas-phase, liquid-phase, or both phases in soils. They may be acted upon by either biological or abiotic processes through advection and/or diffusion. Furthermore, parent and daughter radionuclides may decay as they are transported in the soil. This is volume two to the CASCADER series, titled CASCADR8. It embodies the concepts presented in volume one of this series. To properly understand how the CASCADR8 model works, the reader should read volume one first. This volume presents the input and output file structure for CASCADR8, and a set of realistic scenarios for buried sources of radon gas

  10. CASCADER: An M-chain gas-phase radionuclide transport and fate model

    International Nuclear Information System (INIS)

    Cawlfield, D.E.; Emer, D.F.; Lindstrom, F.T.; Shott, G.J.

    1993-09-01

    Chemicals and radionuclides move either in the gas-phase, liquid-phase, or both phases in soils. They may be acted upon by either biological or abiotic processes through advection and/or dispersion. Additionally during the transport of parent and daughter radionuclides in soil, radionuclide decay may occur. This version of CASCADER called CASCADR9 starts with the concepts presented in volumes one and three of this series. For a proper understanding of how the model works, the reader should read volume one first. Also presented in this volume is a set of realistic scenarios for buried sources of radon gas, and the input and output file structure for CASCADER9

  11. Streamlining environmental product declarations: a stage model

    Science.gov (United States)

    Lefebvre, Elisabeth; Lefebvre, Louis A.; Talbot, Stephane; Le Hen, Gael

    2001-02-01

    General public environmental awareness and education is increasing, therefore stimulating the demand for reliable, objective and comparable information about products' environmental performances. The recently published standard series ISO 14040 and ISO 14025 are normalizing the preparation of Environmental Product Declarations (EPDs) containing comprehensive information relevant to a product's environmental impact during its life cycle. So far, only a few environmentally leading manufacturing organizations have experimented the preparation of EPDs (mostly from Europe), demonstrating its great potential as a marketing weapon. However the preparation of EPDs is a complex process, requiring collection and analysis of massive amounts of information coming from disparate sources (suppliers, sub-contractors, etc.). In a foreseeable future, the streamlining of the EPD preparation process will require product manufacturers to adapt their information systems (ERP, MES, SCADA) in order to make them capable of gathering, and transmitting the appropriate environmental information. It also requires strong functional integration all along the product supply chain in order to ensure that all the information is made available in a standardized and timely manner. The goal of the present paper is two fold: first to propose a transitional model towards green supply chain management and EPD preparation; second to identify key technologies and methodologies allowing to streamline the EPD process and subsequently the transition toward sustainable product development

  12. Fate of bone marrow stromal cells in a syngenic model of bone formation.

    Science.gov (United States)

    Boukhechba, Florian; Balaguer, Thierry; Bouvet-Gerbettaz, Sébastien; Michiels, Jean-François; Bouler, Jean-Michel; Carle, Georges F; Scimeca, Jean-Claude; Rochet, Nathalie

    2011-09-01

    Bone marrow stromal cells (BMSCs) have been demonstrated to induce bone formation when associated to osteoconductive biomaterials and implanted in vivo. Nevertheless, their role in bone reconstruction is not fully understood and rare studies have been conducted to follow their destiny after implantation in syngenic models. The aim of the present work was to use sensitive and quantitative methods to track donor and recipient cells after implantation of BMSCs in a syngenic model of ectopic bone formation. Using polymerase chain reaction (PCR) amplification of the Sex determining Region Y (Sry) gene and in situ hybridization of the Y chromosome in parallel to histological analysis, we have quantified within the implants the survival of the donor cells and the colonization by the recipient cells. The putative migration of the BMSCs in peripheral organs was also analyzed. We show here that grafted cells do not survive more than 3 weeks after implantation and might migrate in peripheral lymphoid organs. These cells are responsible for the attraction of host cells within the implants, leading to the centripetal colonization of the biomaterial by new bone.

  13. The role of pesticide fate modelling in a prevention-led approach to potable water quality management

    Science.gov (United States)

    Dolan, Tom; Pullan, Stephanie; Whelan, Mick; Parsons, David

    2013-04-01

    Diffuse inputs from agriculture are commonly the main source of pesticide contamination in surface water and may have implications for the quality of treated drinking water. After privatisation in 1991, UK water companies primarily focused on the provision of sufficient water treatment to reduce the risk of non-compliance with the European Drinking Water Directive (DWD), under which all pesticide concentrations must be below 0.1µg/l and UK Water Supply Regulations for the potable water they supply. Since 2000, Article 7 of the Water Framework Directive (WFD) has begun to drive a prevention-led approach to compliance with the DWD. As a consequence water companies are now more interested in the quality of 'raw' (untreated) water at the point of abstraction. Modelling (based upon best available estimates of cropping, pesticide use, weather conditions, pesticide characteristics, and catchment characteristics) and monitoring of raw water quality can both help to determine the compliance risks associated with the quality of this 'raw' water resource. This knowledge allows water companies to prioritise active substances for action in their catchments, and is currently used in many cases to support the design of monitoring programmes for pesticide active substances. Additional value can be provided if models are able to help to identify the type and scale of catchment management interventions required to achieve DWD compliance for pesticide active substances through pollution prevention at source or along transport pathways. These questions were explored using a simple catchment-scale pesticide fate and transport model. The model employs a daily time-step and is semi-lumped with calculations performed for soil type and crop combinations, weighted by their proportions within the catchment. Soil properties are derived from the national soil database and the model can, therefore, be applied to any catchment in England and Wales. Various realistic catchment management

  14. Fecal bacteria in the rivers of the Seine drainage network (France): sources, fate and modelling.

    Science.gov (United States)

    Servais, Pierre; Garcia-Armisen, Tamara; George, Isabelle; Billen, Gilles

    2007-04-01

    in different types of rivers within the watershed showing, in summer conditions, no major difference in the mortality rates in small and large rivers. As a result of these studies, a module describing the dynamics of fecal bacteria has been developed and embedded within a hydro-ecological model describing the functioning of the rivers of the whole watershed (the SENEQUE model). Once validated, such a model can be used for testing predictive scenarios and thus can be a very useful tool for the management of microbiological water quality at the scale of the whole basin.

  15. Frozen into stripes: fate of the critical Ising model after a quench.

    Science.gov (United States)

    Blanchard, T; Picco, M

    2013-09-01

    In this article we study numerically the final state of the two-dimensional ferromagnetic critical Ising model after a quench to zero temperature. Beginning from equilibrium at T_{c}, the system can be blocked in a variety of infinitely long lived stripe states in addition to the ground state. Similar results have already been obtained for an infinite temperature initial condition and an interesting connection to exact percolation crossing probabilities has emerged. Here we complete this picture by providing an example of stripe states precisely related to initial crossing probabilities for various boundary conditions. We thus show that this is not specific to percolation but rather that it depends on the properties of spanning clusters in the initial state.

  16. Fate of Staphylococcus aureus in radiation sterilized model food systems simulating dairy products

    International Nuclear Information System (INIS)

    Sulebele, G.A.; Kamat, M.Y.

    1976-01-01

    Gamma irradiation was successfully employed for the development of sterile model food systems simulating dairy products such as pedha and cottage cheese which were inoculated with enterotoxigenic S.aureus S-6 and FR1-100 either individually or in association with S.epidermids and other mixed flora comprising of gram-positive, gram-negative and lactic bacteria and stored at 4 and 35 degC for 6-8 weeks. Pedha failed to support growth of S.aureus while cottage cheese favoured profuse growth of the pathogen. S.epidermidis exhibited a synergistic effect on the growth of S.aureus in cottage cheese. Baired-Parker's medium showed very poor recovery of S.aureus which necessitated the development of a new selective medium for the enumeration of staphylococci in processed foods. (author)

  17. Qualitatively Modeling solute fate and transport across scales in an agricultural catchment with diverse lithology

    Science.gov (United States)

    Wayman, C. R.; Russo, T. A.; Li, L.; Forsythe, B.; Hoagland, B.

    2017-12-01

    As part of the Susquehanna Shale Hills Critical Zone Observatory (SSHCZO) project, we have collected geochemical and hydrological data from several subcatchments and four monitoring sites on the main stem of Shaver's Creek, in Huntingon county, Pennsylvania. One subcatchment (0.43 km2) is under agricultural land use, and the monitoring locations on the larger Shaver's Creek (up to 163 km2) drain watersheds with 0 to 25% agricultural area. These two scales of investigation, coupled with advances made across the SSHCZO on multiple lithologies allow us to extrapolate from the subcatchment to the larger watershed. We use geochemical surface and groundwater data to estimate the solute and water transport regimes within the catchment, and to show how lithology and land use are major controls on ground and surface water quality. One area of investigation includes the transport of nutrients between interflow and regional groundwater, and how that connectivity may be reflected in local surface waters. Water and nutrient (Nitrogen) isotopes, will be used to better understand the relative contributions of local and regional groundwater and interflow fluxes into nearby streams. Following initial qualitative modeling, multiple hydrologic and nutrient transport models (e.g. SWAT and CYCLES/PIHM) will be evaluated from the subcatchment to large watershed scales. We will evaluate the ability to simulate the contributions of regional groundwater versus local groundwater, and also impacts of agricultural land management on surface water quality. Improving estimations of groundwater contributions to stream discharge will provide insight into how much agricultural development can impact stream quality and nutrient loading.

  18. Fate of As(V)-treated nano zero-valent iron: determination of arsenic desorption potential under varying environmental conditions by phosphate extraction.

    Science.gov (United States)

    Dong, Haoran; Guan, Xiaohong; Lo, Irene M C

    2012-09-01

    Nano zero-valent iron (NZVI) offers a promising approach for arsenic remediation, but the spent NZVI with elevated arsenic content could arouse safety concerns. This study investigated the fate of As(V)-treated NZVI (As-NZVI), by examining the desorption potential of As under varying conditions. The desorption kinetics of As from As-NZVI as induced by phosphate was well described by a biphasic rate model. The effects of As(V)/NZVI mass ratio, pH, and aging time on arsenic desorption from As-NZVI by phosphate were investigated. Less arsenic desorption was observed at lower pH or higher As(V)/NZVI mass ratio, where stronger complexes (bidentate) formed between As(V) and NZVI corrosion products as indicated by FTIR analysis. Compared with the fresh As-NZVI, the amount of phosphate-extractable As significantly decreased in As-NZVI aged for 30 or 60 days. The results of the sequential extraction experiments demonstrated that a larger fraction of As was sorbed in the crystalline phases after aging, making it less susceptible to phosphate displacement. However, at pH 9, a slightly higher proportion of phosphate-extractable As was observed in the 60-day sample than in the 30-day sample. XPS results revealed the transformation of As(V) to more easily desorbed As(III) during aging and a higher As(III)/As(V) ratio in the 60-day sample at pH 9, which might have resulted in the higher desorption. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. The energy-environmental profile of building bio-materials. A decision-making model

    International Nuclear Information System (INIS)

    Beccali, G.; Cellura, M.; Lo Cicero

    2000-01-01

    In this article it is presented a reckoning model used for comparing concrete blocks made with recycled aggregates with blocks realised with quarry inerts. Both algorithm and procedural passages are easily transferable to handmade products having different characteristics. From the results one can infer how an open circuit recycling process allows to improve energy-environmental performances of the handmade product even when the technological performances of the blocks are essentially similar. This underlines the importance of a procedural approach taking into account environmental design right from the start of the planning process, also as far as the final fate of the building material at the end of its useful life is concerned [it

  20. Integrated fate modeling for exposure assessment of produced water on the Sable Island Bank (Scotian shelf, Canada).

    Science.gov (United States)

    Berry, Jody A; Wells, Peter G

    2004-10-01

    Produced water is the largest waste discharge from the production phase of oil and gas wells. Produced water is a mixture of reservoir formation water and production chemicals from the separation process. This creates a chemical mixture that has several components of toxic concern, ranging from heavy metals to soluble hydrocarbons. Analysis of potential environmental effects from produced water in the Sable Island Bank region (NS, Canada) was conducted using an integrated modeling approach according to the ecological risk assessment framework. A hydrodynamic dispersion model was used to describe the wastewater plume. A second fugacity-based model was used to describe the likely plume partitioning in the local environmental media of water, suspended sediment, biota, and sediment. Results from the integrated modeling showed that the soluble benzene and naphthalene components reach chronic no-effect concentration levels at a distance of 1.0 m from the discharge point. The partition modeling indicated that low persistence was expected because of advection forces caused by tidal currents for the Sable Island Bank system. The exposure assessment for the two soluble hydrocarbon components suggests that the risks of adverse environmental effects from produced water on Sable Island Bank are low.

  1. Theoretically exploring direct and indirect chemical effects across ecological and exposure scenarios using mechanistic fate and effects modelling

    NARCIS (Netherlands)

    Laender, de F.; Morselli, M.; Baveco, H.; Brink, van den P.J.; Guardo, Di A.

    2015-01-01

    Predicting ecosystem response to chemicals is a complex problem in ecotoxicology and a challenge for risk assessors. The variables potentially influencing chemical fate and exposure define the exposure scenario while the variables determining effects at the ecosystem level define the ecological

  2. Modeling The Fate of Sumatran Elephants in Bukit Tigapuluh Indonesia: Research Needs & Implications for Population Management

    Directory of Open Access Journals (Sweden)

    Alexander Markus Moßbrucker

    2016-01-01

    Full Text Available The critically endangered Sumatran elephant persists in mainly small and isolated populations that may require intensive management to be viable in the long term. Population Viability Analysis (PVA provides the opportunity to evaluate conservation strategies and objectives prior to implementation, which can be very valuable for site managers by supporting their decision making process. This study applies PVA to a local population of Sumatran elephants roaming the Bukit Tigapuluh landscape, Sumatra, with the main goal to explore the impact of pre-selected conservation measures and population scenarios on both population growth rate and extinction probability. Sensitivity testing revealed considerable parameter uncertainties that should be addressed by targeted research projects in order to improve the predictive power of the baseline population model. Given that further habitat destruction can be prevented, containing illegal killings appears to be of highest priority among the tested conservation measures and represents a mandatory pre-condition for activities addressing inbreeding depression such as elephant translocation or the establishment of a conservation corridor.

  3. Epigenetics of cell fate reprogramming and its implications for neurological disorders modelling.

    Science.gov (United States)

    Grzybek, Maciej; Golonko, Aleksandra; Walczak, Marta; Lisowski, Pawel

    2017-03-01

    The reprogramming of human induced pluripotent stem cells (hiPSCs) proceeds in a stepwise manner with reprogramming factors binding and epigenetic composition changes during transition to maintain the epigenetic landscape, important for pluripotency. There arises a question as to whether the aberrant epigenetic state after reprogramming leads to epigenetic defects in induced stem cells causing unpredictable long term effects in differentiated cells. In this review, we present a comprehensive view of epigenetic alterations accompanying reprogramming, cell maintenance and differentiation as factors that influence applications of hiPSCs in stem cell based technologies. We conclude that sample heterogeneity masks DNA methylation signatures in subpopulations of cells and thus believe that beside a genetic evaluation, extensive epigenomic screening should become a standard procedure to ensure hiPSCs state before they are used for genome editing and differentiation into neurons of interest. In particular, we suggest that exploitation of the single-cell composition of the epigenome will provide important insights into heterogeneity within hiPSCs subpopulations to fast forward development of reliable hiPSC-based analytical platforms in neurological disorders modelling and before completed hiPSC technology will be implemented in clinical approaches. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. A motivational model for environmentally responsible behavior.

    Science.gov (United States)

    Tabernero, Carmen; Hernández, Bernardo

    2012-07-01

    This paper presents a study examining whether self-efficacy and intrinsic motivation are related to environmentally responsible behavior (ERB). The study analysed past environmental behavior, self-regulatory mechanisms (self-efficacy, satisfaction, goals), and intrinsic and extrinsic motivation in relation to ERBs in a sample of 156 university students. Results show that all the motivational variables studied are linked to ERB. The effects of self-efficacy on ERB are mediated by the intrinsic motivation responses of the participants. A theoretical model was created by means of path analysis, revealing the power of motivational variables to predict ERB. Structural equation modeling was used to test and fit the research model. The role of motivational variables is discussed with a view to creating adequate learning contexts and experiences to generate interest and new sensations in which self-efficacy and affective reactions play an important role.

  5. It is the economy, stupid! Projecting the fate of fish populations using ecological-economic modeling.

    Science.gov (United States)

    Quaas, Martin F; Reusch, Thorsten B H; Schmidt, Jörn O; Tahvonen, Olli; Voss, Rudi

    2016-01-01

    Four marine fish species are among the most important on the world market: cod, salmon, tuna, and sea bass. While the supply of North American and European markets for two of these species - Atlantic salmon and European sea bass - mainly comes from fish farming, Atlantic cod and tunas are mainly caught from wild stocks. We address the question what will be the status of these wild stocks in the midterm future, in the year 2048, to be specific. Whereas the effects of climate change and ecological driving forces on fish stocks have already gained much attention, our prime interest is in studying the effects of changing economic drivers, as well as the impact of variable management effectiveness. Using a process-based ecological-economic multispecies optimization model, we assess the future stock status under different scenarios of change. We simulate (i) technological progress in fishing, (ii) increasing demand for fish, and (iii) increasing supply of farmed fish, as well as the interplay of these driving forces under different scenarios of (limited) fishery management effectiveness. We find that economic change has a substantial effect on fish populations. Increasing aquaculture production can dampen the fishing pressure on wild stocks, but this effect is likely to be overwhelmed by increasing demand and technological progress, both increasing fishing pressure. The only solution to avoid collapse of the majority of stocks is institutional change to improve management effectiveness significantly above the current state. We conclude that full recognition of economic drivers of change will be needed to successfully develop an integrated ecosystem management and to sustain the wild fish stocks until 2048 and beyond. © 2015 John Wiley & Sons Ltd.

  6. Fate of Lactococcus lactis starter cultures during late ripening in cheese models.

    Science.gov (United States)

    Ruggirello, Marianna; Cocolin, Luca; Dolci, Paola

    2016-10-01

    The presence of Lactococcus lactis, commonly employed as starter culture, was, recently, highlighted and investigated during late cheese ripening. Thus, the main goal of the present study was to assess the persistence and viability of this microorganism throughout manufacturing and ripening of model cheeses. Eight commercial starters, constituted of L. lactis subsp. lactis and L. lactis subsp. cremoris, were inoculated in pasteurized milk in order to manufacture miniature cheeses, ripened for six months. Samples were analysed at different steps (milk after inoculum, curd after cutting, curd after pressing and draining, cheese immediately after salting and cheese at 7, 15, 30, 60, 90, 120, 150 and 180 days of ripening) and submitted to both culture-dependent (traditional plating on M17) and -independent analysis (reverse transcription-quantitative PCR). On the basis of direct RNA analysis, L. lactis populations were detected in all miniature cheeses up to the sixth month of ripening, confirming the presence of viable cells during the whole ripening process, including late stages. Noteworthy, L. lactis was detected by RT-qPCR in cheese samples also when traditional plating failed to indicate its presence. This discrepancy could be explain with the fact that lactococci, during ripening process, enter in a stressed physiological state (viable not culturable, VNC), which might cause their inability to grow on synthetic medium despite their viability in cheese matrix. Preliminary results obtained by "resuscitation" assays corroborated this hypothesis and 2.5% glucose enrichment was effective to recover L. lactis cells in VNC state. The capability of L. lactis to persist in late ripening, and the presence of VNC cells which are known to shift their catabolism to peptides and amino acids consumption, suggests a possible technological role of this microorganism in cheese ripening with a possible impact on flavour formation. Copyright © 2016 Elsevier Ltd. All rights

  7. Modeling climate diversity, tidal dynamics and the fate of volatiles on TRAPPIST-1 planets

    Science.gov (United States)

    Turbet, Martin; Bolmont, Emeline; Leconte, Jeremy; Forget, François; Selsis, Franck; Tobie, Gabriel; Caldas, Anthony; Naar, Joseph; Gillon, Michaël

    2018-05-01

    TRAPPIST-1 planets are invaluable for the study of comparative planetary science outside our solar system and possibly habitability. Both transit timing variations (TTV) of the planets and the compact, resonant architecture of the system suggest that TRAPPIST-1 planets could be endowed with various volatiles today. First, we derived from N-body simulations possible planetary evolution scenarios, and show that all the planets are likely in synchronous rotation. We then used a versatile 3D global climate model (GCM) to explore the possible climates of cool planets around cool stars, with a focus on the TRAPPIST-1 system. We investigated the conditions required for cool planets to prevent possible volatile species to be lost permanently by surface condensation, irreversible burying or photochemical destruction. We also explored the resilience of the same volatiles (when in condensed phase) to a runaway greenhouse process. We find that background atmospheres made of N2, CO, or O2 are rather resistant to atmospheric collapse. However, even if TRAPPIST-1 planets were able to sustain a thick background atmosphere by surviving early X/EUV radiation and stellar wind atmospheric erosion, it is difficult for them to accumulate significant greenhouse gases like CO2, CH4, or NH3. CO2 can easily condense on the permanent nightside, forming CO2 ice glaciers that would flow toward the substellar region. A complete CO2 ice surface cover is theoretically possible on TRAPPIST-1g and h only, but CO2 ices should be gravitationally unstable and get buried beneath the water ice shell in geologically short timescales. Given TRAPPIST-1 planets large EUV irradiation (at least 103 × Titan's flux), CH4 and NH3 are photodissociated rapidly and are thus hard to accumulate in the atmosphere. Photochemical hazes could then sedimentate and form a surface layer of tholins that would progressively thicken over the age of the TRAPPIST-1 system. Regarding habitability, we confirm that few bars of CO2

  8. Environmental Governance as a Model of Environmental Management

    Directory of Open Access Journals (Sweden)

    Budi Kristianto

    2016-02-01

    Full Text Available The concept of environmental governance does not promise practical solutions and provides short guidance in solving intertwined environmental problems in Indonesia. But at least environmental concept is useful when we try to realize environmental management in Indonesia currently. The worst is that the mistake has become routine manifesting in pragmatism in environmental management. Before it all too late, it is better that we keep in mind a German proverb in the beginning of this writing, which more or less, means “ we do not know what the future brings, but we know that we should act.”

  9. Atmospheric dispersion models for environmental pollution applications

    International Nuclear Information System (INIS)

    Gifford, F.A.

    1976-01-01

    Pollutants are introduced into the air by many of man's activities. The potentially harmful effects these can cause are, broadly speaking, of two kinds: long-term, possibly large-scale and wide-spread chronic effects, including long-term effects on the earth's climate; and acute, short-term effects such as those associated with urban air pollution. This section is concerned with mathematical cloud or plume models describing the role of the atmosphere, primarily in relation to the second of these, the acute effects of air pollution, i.e., those arising from comparatively high concentration levels. The need for such air pollution modeling studies has increased spectacularly as a result of the National Environmental Policy Act of 1968 and, especially, two key court decisions; the Calvert Cliffs decision, and the Sierra Club ruling on environmental non-degradation

  10. Uncertainty associated with selected environmental transport models

    International Nuclear Information System (INIS)

    Little, C.A.; Miller, C.W.

    1979-11-01

    A description is given of the capabilities of several models to predict accurately either pollutant concentrations in environmental media or radiological dose to human organs. The models are discussed in three sections: aquatic or surface water transport models, atmospheric transport models, and terrestrial and aquatic food chain models. Using data published primarily by model users, model predictions are compared to observations. This procedure is infeasible for food chain models and, therefore, the uncertainty embodied in the models input parameters, rather than the model output, is estimated. Aquatic transport models are divided into one-dimensional, longitudinal-vertical, and longitudinal-horizontal models. Several conclusions were made about the ability of the Gaussian plume atmospheric dispersion model to predict accurately downwind air concentrations from releases under several sets of conditions. It is concluded that no validation study has been conducted to test the predictions of either aquatic or terrestrial food chain models. Using the aquatic pathway from water to fish to an adult for 137 Cs as an example, a 95% one-tailed confidence limit interval for the predicted exposure is calculated by examining the distributions of the input parameters. Such an interval is found to be 16 times the value of the median exposure. A similar one-tailed limit for the air-grass-cow-milk-thyroid for 131 I and infants was 5.6 times the median dose. Of the three model types discussed in this report,the aquatic transport models appear to do the best job of predicting observed concentrations. However, this conclusion is based on many fewer aquatic validation data than were availaable for atmospheric model validation

  11. Scandinavian belief in fate

    Directory of Open Access Journals (Sweden)

    Åke Ström

    1967-02-01

    Full Text Available In point of principle, Christianity does not give room for any belief in fate. Astrology, horoscopes, divination, etc., are strictly rejected. Belief in fate never disappeared in Christian countries, nor did it in Scandinavia in Christian times. Especially in folklore we can find it at any period: People believed in an implacable fate. All folklore is filled up with this belief in destiny. Nobody can escape his fate. The future lies in the hands of fate, and the time to come takes its form according to inscrutable laws. The pre-Christian period in Scandinavia, dominated by pagan Norse religion, and the secularized epoch of the 20th century, however, show more distinctive and more widespread beliefs in fate than does the Christian period. The present paper makes a comparison between these forms of belief.

  12. Environmental Models as a Service: Enabling Interoperability ...

    Science.gov (United States)

    Achieving interoperability in environmental modeling has evolved as software technology has progressed. The recent rise of cloud computing and proliferation of web services initiated a new stage for creating interoperable systems. Scientific programmers increasingly take advantage of streamlined deployment processes and affordable cloud access to move algorithms and data to the web for discoverability and consumption. In these deployments, environmental models can become available to end users through RESTful web services and consistent application program interfaces (APIs) that consume, manipulate, and store modeling data. RESTful modeling APIs also promote discoverability and guide usability through self-documentation. Embracing the RESTful paradigm allows models to be accessible via a web standard, and the resulting endpoints are platform- and implementation-agnostic while simultaneously presenting significant computational capabilities for spatial and temporal scaling. RESTful APIs present data in a simple verb-noun web request interface: the verb dictates how a resource is consumed using HTTP methods (e.g., GET, POST, and PUT) and the noun represents the URL reference of the resource on which the verb will act. The RESTful API can self-document in both the HTTP response and an interactive web page using the Open API standard. This lets models function as an interoperable service that promotes sharing, documentation, and discoverability. Here, we discuss the

  13. Transformation and distribution processes governing the fate and behaviour of nanomaterials in the environment: an overview

    DEFF Research Database (Denmark)

    Hansen, Steffen Foss; Hartmann, Nanna B.; Baun, Anders

    2015-01-01

    assessment. Chemical fate modelling is one approach to fill this gap within a short time frame. To ensure the reliability of predicted environmental concentrations informed choices are needed during model formulation and development. A major knowledge gap, hampering the further development of such model...... present in the environment. Specific nanomaterials are used as case studies to illustrate these processes. Key environmental processes are identified and ranked and key knowledge gaps are identified, feeding into the longer-term goal of improving the existing models for predicted environmental...

  14. Towards policy relevant environmental modeling: contextual validity and pragmatic models

    Science.gov (United States)

    Miles, Scott B.

    2000-01-01

    "What makes for a good model?" In various forms, this question is a question that, undoubtedly, many people, businesses, and institutions ponder with regards to their particular domain of modeling. One particular domain that is wrestling with this question is the multidisciplinary field of environmental modeling. Examples of environmental models range from models of contaminated ground water flow to the economic impact of natural disasters, such as earthquakes. One of the distinguishing claims of the field is the relevancy of environmental modeling to policy and environment-related decision-making in general. A pervasive view by both scientists and decision-makers is that a "good" model is one that is an accurate predictor. Thus, determining whether a model is "accurate" or "correct" is done by comparing model output to empirical observations. The expected outcome of this process, usually referred to as "validation" or "ground truthing," is a stamp on the model in question of "valid" or "not valid" that serves to indicate whether or not the model will be reliable before it is put into service in a decision-making context. In this paper, I begin by elaborating on the prevailing view of model validation and why this view must change. Drawing from concepts coming out of the studies of science and technology, I go on to propose a contextual view of validity that can overcome the problems associated with "ground truthing" models as an indicator of model goodness. The problem of how we talk about and determine model validity has much to do about how we perceive the utility of environmental models. In the remainder of the paper, I argue that we should adopt ideas of pragmatism in judging what makes for a good model and, in turn, developing good models. From such a perspective of model goodness, good environmental models should facilitate communication, convey—not bury or "eliminate"—uncertainties, and, thus, afford the active building of consensus decisions, instead

  15. Developing and applying a site-specific multimedia fate model to address ecological risk of oxytetracycline discharged with aquaculture effluent in coastal waters off Jangheung, Korea.

    Science.gov (United States)

    Kim, Woojung; Lee, Yunho; Kim, Sang Don

    2017-11-01

    The overuse of oxytetracycline (OTC) in aquaculture has become a problem because of its chronic toxic effects on marine ecosystems. The present study assessed the ecological risk of OTC in the coastal waters near the Jangheung Flatfish Farm using a site-specific multimedia fate model to analyze exposure. Before the model was applied, its performance was validated by comparing it with field data. The coastal waters in the testbed were sampled and analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) followed by solid-phase extraction (SPE). The concentrations of OTC measured varied from 7.05 to 95.39ng/L. The results of validating the models showed that the site-specific multimedia fate model performed better (root mean square error (RMSE): 24.217, index of agreement (IOA): 0.739) than conventional fugacity approaches. This result demonstrated the utility of this model in supporting effective future management of aquaculture effluent. The results of probabilistic risk assessment indicated that OTC from aquaculture effluent did not cause adverse effects, even in a maximum-use scenario. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Model evaluation methodology applicable to environmental assessment models

    International Nuclear Information System (INIS)

    Shaeffer, D.L.

    1979-08-01

    A model evaluation methodology is presented to provide a systematic framework within which the adequacy of environmental assessment models might be examined. The necessity for such a tool is motivated by the widespread use of models for predicting the environmental consequences of various human activities and by the reliance on these model predictions for deciding whether a particular activity requires the deployment of costly control measures. Consequently, the uncertainty associated with prediction must be established for the use of such models. The methodology presented here consists of six major tasks: model examination, algorithm examination, data evaluation, sensitivity analyses, validation studies, and code comparison. This methodology is presented in the form of a flowchart to show the logical interrelatedness of the various tasks. Emphasis has been placed on identifying those parameters which are most important in determining the predictive outputs of a model. Importance has been attached to the process of collecting quality data. A method has been developed for analyzing multiplicative chain models when the input parameters are statistically independent and lognormally distributed. Latin hypercube sampling has been offered as a promising candidate for doing sensitivity analyses. Several different ways of viewing the validity of a model have been presented. Criteria are presented for selecting models for environmental assessment purposes

  17. Models and parameters for environmental radiological assessments

    International Nuclear Information System (INIS)

    Miller, C.W.

    1983-01-01

    This article reviews the forthcoming book Models and Parameters for Environmental Radiological Assessments, which presents a unified compilation of models and parameters for assessing the impact on man of radioactive discharges, both routine and accidental, into the environment. Models presented in this book include those developed for the prediction of atmospheric and hydrologic transport and deposition, for terrestrial and aquatic food-chain bioaccumulation, and for internal and external dosimetry. Summaries are presented for each of the transport and dosimetry areas previously for each of the transport and dosimetry areas previously mentioned, and details are available in the literature cited. A chapter of example problems illustrates many of the methodologies presented throughout the text. Models and parameters presented are based on the results of extensive literature reviews and evaluations performed primarily by the staff of the Health and Safety Research Division of Oak Ridge National Laboratory

  18. Underwater noise modelling for environmental impact assessment

    Energy Technology Data Exchange (ETDEWEB)

    Farcas, Adrian [Centre for Environment, Fisheries and Aquaculture Science (Cefas), Pakefield Road, Lowestoft, NR33 0HT (United Kingdom); Thompson, Paul M. [Lighthouse Field Station, Institute of Biological and Environmental Sciences, University of Aberdeen, Cromarty IV11 8YL (United Kingdom); Merchant, Nathan D., E-mail: nathan.merchant@cefas.co.uk [Centre for Environment, Fisheries and Aquaculture Science (Cefas), Pakefield Road, Lowestoft, NR33 0HT (United Kingdom)

    2016-02-15

    Assessment of underwater noise is increasingly required by regulators of development projects in marine and freshwater habitats, and noise pollution can be a constraining factor in the consenting process. Noise levels arising from the proposed activity are modelled and the potential impact on species of interest within the affected area is then evaluated. Although there is considerable uncertainty in the relationship between noise levels and impacts on aquatic species, the science underlying noise modelling is well understood. Nevertheless, many environmental impact assessments (EIAs) do not reflect best practice, and stakeholders and decision makers in the EIA process are often unfamiliar with the concepts and terminology that are integral to interpreting noise exposure predictions. In this paper, we review the process of underwater noise modelling and explore the factors affecting predictions of noise exposure. Finally, we illustrate the consequences of errors and uncertainties in noise modelling, and discuss future research needs to reduce uncertainty in noise assessments.

  19. Underwater noise modelling for environmental impact assessment

    International Nuclear Information System (INIS)

    Farcas, Adrian; Thompson, Paul M.; Merchant, Nathan D.

    2016-01-01

    Assessment of underwater noise is increasingly required by regulators of development projects in marine and freshwater habitats, and noise pollution can be a constraining factor in the consenting process. Noise levels arising from the proposed activity are modelled and the potential impact on species of interest within the affected area is then evaluated. Although there is considerable uncertainty in the relationship between noise levels and impacts on aquatic species, the science underlying noise modelling is well understood. Nevertheless, many environmental impact assessments (EIAs) do not reflect best practice, and stakeholders and decision makers in the EIA process are often unfamiliar with the concepts and terminology that are integral to interpreting noise exposure predictions. In this paper, we review the process of underwater noise modelling and explore the factors affecting predictions of noise exposure. Finally, we illustrate the consequences of errors and uncertainties in noise modelling, and discuss future research needs to reduce uncertainty in noise assessments.

  20. Knowledge-Based Environmental Context Modeling

    Science.gov (United States)

    Pukite, P. R.; Challou, D. J.

    2017-12-01

    As we move from the oil-age to an energy infrastructure based on renewables, the need arises for new educational tools to support the analysis of geophysical phenomena and their behavior and properties. Our objective is to present models of these phenomena to make them amenable for incorporation into more comprehensive analysis contexts. Starting at the level of a college-level computer science course, the intent is to keep the models tractable and therefore practical for student use. Based on research performed via an open-source investigation managed by DARPA and funded by the Department of Interior [1], we have adapted a variety of physics-based environmental models for a computer-science curriculum. The original research described a semantic web architecture based on patterns and logical archetypal building-blocks (see figure) well suited for a comprehensive environmental modeling framework. The patterns span a range of features that cover specific land, atmospheric and aquatic domains intended for engineering modeling within a virtual environment. The modeling engine contained within the server relied on knowledge-based inferencing capable of supporting formal terminology (through NASA JPL's Semantic Web for Earth and Environmental Technology (SWEET) ontology and a domain-specific language) and levels of abstraction via integrated reasoning modules. One of the key goals of the research was to simplify models that were ordinarily computationally intensive to keep them lightweight enough for interactive or virtual environment contexts. The breadth of the elements incorporated is well-suited for learning as the trend toward ontologies and applying semantic information is vital for advancing an open knowledge infrastructure. As examples of modeling, we have covered such geophysics topics as fossil-fuel depletion, wind statistics, tidal analysis, and terrain modeling, among others. Techniques from the world of computer science will be necessary to promote efficient

  1. Global Environmental Change: An integrated modelling approach

    International Nuclear Information System (INIS)

    Den Elzen, M.

    1993-01-01

    Two major global environmental problems are dealt with: climate change and stratospheric ozone depletion (and their mutual interactions), briefly surveyed in part 1. In Part 2 a brief description of the integrated modelling framework IMAGE 1.6 is given. Some specific parts of the model are described in more detail in other Chapters, e.g. the carbon cycle model, the atmospheric chemistry model, the halocarbon model, and the UV-B impact model. In Part 3 an uncertainty analysis of climate change and stratospheric ozone depletion is presented (Chapter 4). Chapter 5 briefly reviews the social and economic uncertainties implied by future greenhouse gas emissions. Chapters 6 and 7 describe a model and sensitivity analysis pertaining to the scientific uncertainties and/or lacunae in the sources and sinks of methane and carbon dioxide, and their biogeochemical feedback processes. Chapter 8 presents an uncertainty and sensitivity analysis of the carbon cycle model, the halocarbon model, and the IMAGE model 1.6 as a whole. Part 4 presents the risk assessment methodology as applied to the problems of climate change and stratospheric ozone depletion more specifically. In Chapter 10, this methodology is used as a means with which to asses current ozone policy and a wide range of halocarbon policies. Chapter 11 presents and evaluates the simulated globally-averaged temperature and sea level rise (indicators) for the IPCC-1990 and 1992 scenarios, concluding with a Low Risk scenario, which would meet the climate targets. Chapter 12 discusses the impact of sea level rise on the frequency of the Dutch coastal defence system (indicator) for the IPCC-1990 scenarios. Chapter 13 presents projections of mortality rates due to stratospheric ozone depletion based on model simulations employing the UV-B chain model for a number of halocarbon policies. Chapter 14 presents an approach for allocating future emissions of CO 2 among regions. (Abstract Truncated)

  2. Examination of the uncertainty in contaminant fate and transport modeling: a case study in the Venice Lagoon.

    Science.gov (United States)

    Sommerfreund, J; Arhonditsis, G B; Diamond, M L; Frignani, M; Capodaglio, G; Gerino, M; Bellucci, L; Giuliani, S; Mugnai, C

    2010-03-01

    A Monte Carlo analysis is used to quantify environmental parametric uncertainty in a multi-segment, multi-chemical model of the Venice Lagoon. Scientific knowledge, expert judgment and observational data are used to formulate prior probability distributions that characterize the uncertainty pertaining to 43 environmental system parameters. The propagation of this uncertainty through the model is then assessed by a comparative analysis of the moments (central tendency, dispersion) of the model output distributions. We also apply principal component analysis in combination with correlation analysis to identify the most influential parameters, thereby gaining mechanistic insights into the ecosystem functioning. We found that modeled concentrations of Cu, Pb, OCDD/F and PCB-180 varied by up to an order of magnitude, exhibiting both contaminant- and site-specific variability. These distributions generally overlapped with the measured concentration ranges. We also found that the uncertainty of the contaminant concentrations in the Venice Lagoon was characterized by two modes of spatial variability, mainly driven by the local hydrodynamic regime, which separate the northern and central parts of the lagoon and the more isolated southern basin. While spatial contaminant gradients in the lagoon were primarily shaped by hydrology, our analysis also shows that the interplay amongst the in-place historical pollution in the central lagoon, the local suspended sediment concentrations and the sediment burial rates exerts significant control on the variability of the contaminant concentrations. We conclude that the probabilistic analysis presented herein is valuable for quantifying uncertainty and probing its cause in over-parameterized models, while some of our results can be used to dictate where additional data collection efforts should focus on and the directions that future model refinement should follow. (c) 2009 Elsevier Inc. All rights reserved.

  3. ENM fate in freshwater through adaption of USEtox

    DEFF Research Database (Denmark)

    Miseljic, Mirko; Birkved, Morten; Olsen, Stig Irving

    Engineered nanomaterials (ENMs) have in recent time received substantial attention, both in scientific and consumer circles, as these materials are introduced to a steadily increasing number of consumer products. This has led to environmental concerns on how this new material class behaves...... in the environment, at which concentrations organisms are exposed to the materials and what effects these materials may have on the environment. In relation to metal-oxide engineered nanomaterials (ENMs), as is the general case for ENMs, many environmental aspects are still unknown and/or hence not properly...... scientifically mapped. One approach that has not been given much attention in relation to environmental assessment of ENM, more precisely the fate, exposure and effect modelling of metal-oxide ENMs is the application of adapted characterization modelling (ACM) and hence application of characterisation models...

  4. "Fate: The short film"

    OpenAIRE

    Maya Quintana, Jennifer

    2014-01-01

    "Fate: The Short Film" is a four minute short film which reflects the idea that nobody can escape from the fate. It has a good picture and sound quality with an understandable message for all public and with the collaboration of actors, filmmaker, stylist, script advisor and media technician.

  5. Innovative mathematical modeling in environmental remediation

    International Nuclear Information System (INIS)

    Yeh, Gour T.; Gwo, Jin Ping; Siegel, Malcolm D.; Li, Ming-Hsu; Fang, Yilin; Zhang, Fan; Luo, Wensui; Yabusaki, Steven B.

    2013-01-01

    There are two different ways to model reactive transport: ad hoc and innovative reaction-based approaches. The former, such as the Kd simplification of adsorption, has been widely employed by practitioners, while the latter has been mainly used in scientific communities for elucidating mechanisms of biogeochemical transport processes. It is believed that innovative mechanistic-based models could serve as protocols for environmental remediation as well. This paper reviews the development of a mechanistically coupled fluid flow, thermal transport, hydrologic transport, and reactive biogeochemical model and example-applications to environmental remediation problems. Theoretical bases are sufficiently described. Four example problems previously carried out are used to demonstrate how numerical experimentation can be used to evaluate the feasibility of different remediation approaches. The first one involved the application of a 56-species uranium tailing problem to the Melton Branch Subwatershed at Oak Ridge National Laboratory (ORNL) using the parallel version of the model. Simulations were made to demonstrate the potential mobilization of uranium and other chelating agents in the proposed waste disposal site. The second problem simulated laboratory-scale system to investigate the role of natural attenuation in potential off-site migration of uranium from uranium mill tailings after restoration. It showed inadequacy of using a single Kd even for a homogeneous medium. The third example simulated laboratory experiments involving extremely high concentrations of uranium, technetium, aluminum, nitrate, and toxic metals (e.g.,Ni, Cr, Co). The fourth example modeled microbially-mediated immobilization of uranium in an unconfined aquifer using acetate amendment in a field-scale experiment. The purposes of these modeling studies were to simulate various mechanisms of mobilization and immobilization of radioactive wastes and to illustrate how to apply reactive transport models

  6. Innovative mathematical modeling in environmental remediation

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, Gour T. [Taiwan Typhoon and Flood Research Institute (Taiwan); National Central Univ. (Taiwan); Univ. of Central Florida (United States); Gwo, Jin Ping [Nuclear Regulatory Commission (NRC), Rockville, MD (United States); Siegel, Malcolm D. [Sandia National Laboratories, Albuquerque, NM (United States); Li, Ming-Hsu [National Central Univ. (Taiwan); ; Fang, Yilin [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Zhang, Fan [Inst. of Tibetan Plateau Research, Chinese Academy of Sciences (China); Luo, Wensui [Inst. of Tibetan Plateau Research, Chinese Academy of Sciences (China); Yabusaki, Steven B. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

    2013-05-01

    There are two different ways to model reactive transport: ad hoc and innovative reaction-based approaches. The former, such as the Kd simplification of adsorption, has been widely employed by practitioners, while the latter has been mainly used in scientific communities for elucidating mechanisms of biogeochemical transport processes. It is believed that innovative mechanistic-based models could serve as protocols for environmental remediation as well. This paper reviews the development of a mechanistically coupled fluid flow, thermal transport, hydrologic transport, and reactive biogeochemical model and example-applications to environmental remediation problems. Theoretical bases are sufficiently described. Four example problems previously carried out are used to demonstrate how numerical experimentation can be used to evaluate the feasibility of different remediation approaches. The first one involved the application of a 56-species uranium tailing problem to the Melton Branch Subwatershed at Oak Ridge National Laboratory (ORNL) using the parallel version of the model. Simulations were made to demonstrate the potential mobilization of uranium and other chelating agents in the proposed waste disposal site. The second problem simulated laboratory-scale system to investigate the role of natural attenuation in potential off-site migration of uranium from uranium mill tailings after restoration. It showed inadequacy of using a single Kd even for a homogeneous medium. The third example simulated laboratory experiments involving extremely high concentrations of uranium, technetium, aluminum, nitrate, and toxic metals (e.g.,Ni, Cr, Co).The fourth example modeled microbially-mediated immobilization of uranium in an unconfined aquifer using acetate amendment in a field-scale experiment. The purposes of these modeling studies were to simulate various mechanisms of mobilization and immobilization of radioactive wastes and to illustrate how to apply reactive transport models

  7. 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)

    Dufois, Francois

    2008-01-01

    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

  8. Development of Dynamic Environmental Effect Calculation Model

    International Nuclear Information System (INIS)

    Jeong, Chang Joon; Ko, Won Il

    2010-01-01

    The short-term, long-term decay heat, and radioactivity are considered as main environmental parameters of SF and HLA. In this study, the dynamic calculation models for radioactivity, short-term decay heat, and long-term heat load of the SF are developed and incorporated into the Doneness code. The spent fuel accumulation has become a major issue for sustainable operation of nuclear power plants. If a once-through fuel cycle is selected, the SF will be disposed into the repository. Otherwise, in case of fast reactor or reuse cycle, the SF will be reprocessed and the high level waste will be disposed

  9. Data for developing metamodels to assess the fate, transport, and bioaccumulation of organic chemicals in rivers. Chemicals have log Kow ranging from 3 to 14, and rivers have mean annual discharges ranging from 1.09 to 3240 m3/s.

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset was developed to demonstrate how metamodels of high resolution, process-based models that simulate the fate, transport, and bioaccumulation of organic...

  10. Data worth and prediction uncertainty for pesticide transport and fate models in Nebraska and Maryland, United States

    Science.gov (United States)

    Nolan, Bernard T.; Malone, Robert W.; Doherty, John E.; Barbash, Jack E.; Ma, Liwang; Shaner, Dale L.

    2015-01-01

    BACKGROUND Complex environmental models are frequently extrapolated to overcome data limitations in space and time, but quantifying data worth to such models is rarely attempted. The authors determined which field observations most informed the parameters of agricultural system models applied to field sites in Nebraska (NE) and Maryland (MD), and identified parameters and observations that most influenced prediction uncertainty. RESULTS The standard error of regression of the calibrated models was about the same at both NE (0.59) and MD (0.58), and overall reductions in prediction uncertainties of metolachlor and metolachlor ethane sulfonic acid concentrations were 98.0 and 98.6% respectively. Observation data groups reduced the prediction uncertainty by 55–90% at NE and by 28–96% at MD. Soil hydraulic parameters were well informed by the observed data at both sites, but pesticide and macropore properties had comparatively larger contributions after model calibration. CONCLUSIONS Although the observed data were sparse, they substantially reduced prediction uncertainty in unsampled regions of pesticide breakthrough curves. Nitrate evidently functioned as a surrogate for soil hydraulic data in well-drained loam soils conducive to conservative transport of nitrogen. Pesticide properties and macropore parameters could most benefit from improved characterization further to reduce model misfit and prediction uncertainty.   

  11. Validated predictive modelling of the environmental resistome.

    Science.gov (United States)

    Amos, Gregory C A; Gozzard, Emma; Carter, Charlotte E; Mead, Andrew; Bowes, Mike J; Hawkey, Peter M; Zhang, Lihong; Singer, Andrew C; Gaze, William H; Wellington, Elizabeth M H

    2015-06-01

    Multi-drug-resistant bacteria pose a significant threat to public health. The role of the environment in the overall rise in antibiotic-resistant infections and risk to humans is largely unknown. This study aimed to evaluate drivers of antibiotic-resistance levels across the River Thames catchment, model key biotic, spatial and chemical variables and produce predictive models for future risk assessment. Sediment samples from 13 sites across the River Thames basin were taken at four time points across 2011 and 2012. Samples were analysed for class 1 integron prevalence and enumeration of third-generation cephalosporin-resistant bacteria. Class 1 integron prevalence was validated as a molecular marker of antibiotic resistance; levels of resistance showed significant geospatial and temporal variation. The main explanatory variables of resistance levels at each sample site were the number, proximity, size and type of surrounding wastewater-treatment plants. Model 1 revealed treatment plants accounted for 49.5% of the variance in resistance levels. Other contributing factors were extent of different surrounding land cover types (for example, Neutral Grassland), temporal patterns and prior rainfall; when modelling all variables the resulting model (Model 2) could explain 82.9% of variations in resistance levels in the whole catchment. Chemical analyses correlated with key indicators of treatment plant effluent and a model (Model 3) was generated based on water quality parameters (contaminant and macro- and micro-nutrient levels). Model 2 was beta tested on independent sites and explained over 78% of the variation in integron prevalence showing a significant predictive ability. We believe all models in this study are highly useful tools for informing and prioritising mitigation strategies to reduce the environmental resistome.

  12. Meta-modeling of the pesticide fate model MACRO for groundwater exposure assessments using artificial neural networks

    Science.gov (United States)

    Stenemo, Fredrik; Lindahl, Anna M. L.; Gärdenäs, Annemieke; Jarvis, Nicholas

    2007-08-01

    Several simple index methods that use easily accessible data have been developed and included in decision-support systems to estimate pesticide leaching across larger areas. However, these methods often lack important process descriptions (e.g. macropore flow), which brings into question their reliability. Descriptions of macropore flow have been included in simulation models, but these are too complex and demanding for spatial applications. To resolve this dilemma, a neural network simulation meta-model of the dual-permeability macropore flow model MACRO was created for pesticide groundwater exposure assessment. The model was parameterized using pedotransfer functions that require as input the clay and sand content of the topsoil and subsoil, and the topsoil organic carbon content. The meta-model also requires the topsoil pesticide half-life and the soil organic carbon sorption coefficient as input. A fully connected feed-forward multilayer perceptron classification network with two hidden layers, linked to fully connected feed-forward multilayer perceptron neural networks with one hidden layer, trained on sub-sets of the target variable, was shown to be a suitable meta-model for the intended purpose. A Fourier amplitude sensitivity test showed that the model output (the 80th percentile average yearly pesticide concentration at 1 m depth for a 20 year simulation period) was sensitive to all input parameters. The two input parameters related to pesticide characteristics (i.e. soil organic carbon sorption coefficient and topsoil pesticide half-life) were the most influential, but texture in the topsoil was also quite important since it was assumed to control the mass exchange coefficient that regulates the strength of macropore flow. This is in contrast to models based on the advection-dispersion equation where soil texture is relatively unimportant. The use of the meta-model is exemplified with a case-study where the spatial variability of pesticide leaching is

  13. Simplified fate, exposure and effect modelling of chemical compounds in the case of lacking complete assessment data sets

    DEFF Research Database (Denmark)

    Birkved, Morten; Heijungs, R; Olsen, Stig Irving

    2004-01-01

    availability limitations to select key parameters that explain much of the variance and at the same time are relatively easily available. Further, PLSR was used to derive linear SBM models. In further investigations multiple linear regression (MLR) will be used to derive predictive equations for SBM...... characterisation factors. The result of this will be tested on common sense and environmental knowledge and a mechanistically understandable SBM will be developed by rounding off the coefficients of the regression equations. Preliminary results including PLSR derived linear SBM’s of this work is presented........g. in terms of how the input parameters enter the regression equation. In the absence of a final OMNIITOX BM a model of similar complexity USES-LCA, has been used as surrogate BM. We have applied partial least square of latent structure regression (PLSR) and combined insights from this with knowledge on data...

  14. Experimental methodology for assessing the environmental fate of organic chemicals in polymer matrices using column leaching studies and OECD 308 water/sediment systems: Application to tire and road wear particles

    International Nuclear Information System (INIS)

    Unice, Kenneth M.; Bare, Jennifer L.; Kreider, Marisa L.; Panko, Julie M.

    2015-01-01

    Automobile tires require functional rubber additives including curing agents and antioxidants, which are potentially environmentally available from tire and road wear particles (TRWP) deposited in soil and sediment. A novel methodology was employed to evaluate the environmental fate of three commonly-used tire chemicals (N-cyclohexylbenzothiazole-2-sulfenamide (CBS), N-(1,3-dimethylbutyl)-N′-phenyl-1,4-phenylenediamine (6-PPD) and 1,3-diphenylguanidine (DPG)), using a road simulator, an artificial weathering chamber, column leaching tests, and OECD 308 sediment/water incubator studies. Environmental release factors were quantified for curing (f C ), tire wear (f W ), terrestrial weathering (f S ), leaching from TRWP (f L ), and environmental availability from TRWP (f A ) by liquid chromatography–tandem mass spectroscopy (LC/MS/MS) analyses. Cumulative fractions representing total environmental availability (F T ) and release to water (F R ) were calculated for the tire chemicals and 13 transformation products. F T for CBS, DPG and 6-PPD inclusive of transformation products for an accelerated terrestrial aging time in soil of 0.1 years was 0.08, 0.1, and 0.06, respectively (equivalent to 6 to 10% of formulated mass). In contrast, a wider range of 5.5 × 10 −4 (6-PPD) to 0.06 (CBS) was observed for F R at an accelerated age of 0.1 years, reflecting the importance of hydrophobicity and solubility for determining the release to the water phase. Significant differences (p < 0.05) in the weathering factor, f S , were observed when chemicals were categorized by boiling point or hydrolysis rate constant. A significant difference in the leaching factor, f L , and environmental availability factor, f A, was also observed when chemicals were categorized by log K ow . Our methodology should be useful for lifecycle analysis of other functional polymer chemicals. - Highlights: • Studied two vulcanization accelerators and an antioxidant additive used in tire tread

  15. Experimental methodology for assessing the environmental fate of organic chemicals in polymer matrices using column leaching studies and OECD 308 water/sediment systems: Application to tire and road wear particles

    Energy Technology Data Exchange (ETDEWEB)

    Unice, Kenneth M., E-mail: ken.unice@cardno.com; Bare, Jennifer L.; Kreider, Marisa L.; Panko, Julie M.

    2015-11-15

    Automobile tires require functional rubber additives including curing agents and antioxidants, which are potentially environmentally available from tire and road wear particles (TRWP) deposited in soil and sediment. A novel methodology was employed to evaluate the environmental fate of three commonly-used tire chemicals (N-cyclohexylbenzothiazole-2-sulfenamide (CBS), N-(1,3-dimethylbutyl)-N′-phenyl-1,4-phenylenediamine (6-PPD) and 1,3-diphenylguanidine (DPG)), using a road simulator, an artificial weathering chamber, column leaching tests, and OECD 308 sediment/water incubator studies. Environmental release factors were quantified for curing (f{sub C}), tire wear (f{sub W}), terrestrial weathering (f{sub S}), leaching from TRWP (f{sub L}), and environmental availability from TRWP (f{sub A}) by liquid chromatography–tandem mass spectroscopy (LC/MS/MS) analyses. Cumulative fractions representing total environmental availability (F{sub T}) and release to water (F{sub R}) were calculated for the tire chemicals and 13 transformation products. F{sub T} for CBS, DPG and 6-PPD inclusive of transformation products for an accelerated terrestrial aging time in soil of 0.1 years was 0.08, 0.1, and 0.06, respectively (equivalent to 6 to 10% of formulated mass). In contrast, a wider range of 5.5 × 10{sup −4} (6-PPD) to 0.06 (CBS) was observed for F{sub R} at an accelerated age of 0.1 years, reflecting the importance of hydrophobicity and solubility for determining the release to the water phase. Significant differences (p < 0.05) in the weathering factor, f{sub S}, were observed when chemicals were categorized by boiling point or hydrolysis rate constant. A significant difference in the leaching factor, f{sub L}, and environmental availability factor, f{sub A,} was also observed when chemicals were categorized by log K{sub ow}. Our methodology should be useful for lifecycle analysis of other functional polymer chemicals. - Highlights: • Studied two vulcanization

  16. A data model for environmental scientists

    Science.gov (United States)

    Kapeljushnik, O.; Beran, B.; Valentine, D.; van Ingen, C.; Zaslavsky, I.; Whitenack, T.

    2008-12-01

    Environmental science encompasses a wide range of disciplines from water chemistry to microbiology, ecology and atmospheric sciences. Studies often require working across disciplines which differ in their ways of describing and storing data such that it is not possible to devise a monolithic one-size-fits-all data solution. Based on our experiences with Consortium of the Universities for the Advancement of Hydrologic Science Inc. (CUAHSI) Observations Data Model, Berkeley Water Center FLUXNET carbon-climate work and by examining standards like EPA's Water Quality Exchange (WQX), we have developed a flexible data model that allows extensions without need to altering the schema such that scientists can define custom metadata elements to describe their data including observations, analysis methods as well as sensors and geographical features. The data model supports various types of observations including fixed point and moving sensors, bottled samples, rasters from remote sensors and models, and categorical descriptions (e.g. taxonomy) by employing user-defined-types when necessary. It leverages ADO .NET Entity Framework to provide the semantic data models for differing disciplines, while maintaining a common schema below the entity layer. This abstraction layer simplifies data retrieval and manipulation by hiding the logic and complexity of the relational schema from users thus allows programmers and scientists to deal directly with objects such as observations, sensors, watersheds, river reaches, channel cross-sections, laboratory analysis methods and samples as opposed to table joins, columns and rows.

  17. Coupling a continuous watershed-scale microbial fate and transport model with a stochastic dose-response model to estimate risk of illness in an urban watershed.

    Science.gov (United States)

    Liao, Hehuan; Krometis, Leigh-Anne H; Kline, Karen

    2016-05-01

    Within the United States, elevated levels of fecal indicator bacteria (FIB) remain the leading cause of surface water-quality impairments requiring formal remediation plans under the federal Clean Water Act's Total Maximum Daily Load (TMDL) program. The sufficiency of compliance with numerical FIB criteria as the targeted endpoint of TMDL remediation plans may be questionable given poor correlations between FIB and pathogenic microorganisms and varying degrees of risk associated with exposure to different fecal pollution sources (e.g. human vs animal). The present study linked a watershed-scale FIB fate and transport model with a dose-response model to continuously predict human health risks via quantitative microbial risk assessment (QMRA), for comparison to regulatory benchmarks. This process permitted comparison of risks associated with different fecal pollution sources in an impaired urban watershed in order to identify remediation priorities. Results indicate that total human illness risks were consistently higher than the regulatory benchmark of 36 illnesses/1000 people for the study watershed, even when the predicted FIB levels were in compliance with the Escherichia coli geometric mean standard of 126CFU/100mL. Sanitary sewer overflows were associated with the greatest risk of illness. This is of particular concern, given increasing indications that sewer leakage is ubiquitous in urban areas, yet not typically fully accounted for during TMDL development. Uncertainty analysis suggested the accuracy of risk estimates would be improved by more detailed knowledge of site-specific pathogen presence and densities. While previous applications of the QMRA process to impaired waterways have mostly focused on single storm events or hypothetical situations, the continuous modeling framework presented in this study could be integrated into long-term water quality management planning, especially the United States' TMDL program, providing greater clarity to watershed

  18. An electricity and environmental policy model

    International Nuclear Information System (INIS)

    Hanson, D.A.

    1993-01-01

    This paper describes work being done to simulate the 1990 Clean Air Act Amendments (CAAA), Title IV, Acidic Deposition Control, which introduced tradable, bankable SO 2 emission allowances. The Title IV simulations are compared with three other scenarios on a regional basis in order to calculate the following: the absolute cost savings of the tradable/ bankable approach, the relative cost savings of the tradable/ bankable approach derived from a baseline of no controls, the environmental improvement, measured in terms of SO 2 emission reduction, that will be achieved under Title IV compared with a more rigid command-and-control regulation with the same cost. Hence, the simulations illustrate the basic point that more efficient market-based regulation can either reduce costs or can provide enhanced environmental quality, or both. It is important for policy formation to get a handle on relative magnitudes. The National Acid Precipitation Assessment Program (NAPAP) 1990 Assessment suggested a 25% cost saving from tradable emission allowances relative to command-and-control. Both the relative savings potential and the absolute savings potential matter because a small relative savings in a large regulatory program may still be worth pursuing. Regional cost reductions and environmental improvements are of particular interest. However, this study goes further to characterize likely SO 2 emission trading patterns within and among utility operating systems. The study also characterizes the coal market and the induced sulfur premiums over time and the market price path for SO 2 emission allowances. It is shown that the sulfur premium is equivalent to the SO 2 allowance price. This paper focuses on the methodology and on the new electric utility planning and compliance model which was designed for the study

  19. Environmental flows in hydro-economic models

    Science.gov (United States)

    Pereau, Jean-Christophe; Pryet, Alexandre

    2018-03-01

    The protection of environmental flows, as a management objective for a regulating agency, needs to be consistent with the aquifer water balance and the degree of resource renewability. A stylized hydro-economic model is used where natural recharge, which sustains environmental flows, is considered both in the aquifer water budget and in the welfare function as ecosystem damage. Groundwater recharge and the associated natural drainage may be neglected for aquifers containing fossil water, where the groundwater is mined. However, when dealing with an aquifer that constitutes a renewable resource, for which recharge is not negligible, natural drainage should explicitly appear in the water budget. In doing so, the optimum path of net extraction rate does not necessarily converge to the recharge rate, but depends on the costs associated with ecosystem damages. The optimal paths and equilibrium values for the water volume and water extraction are analytically derived, and numerical simulations based on the Western La Mancha aquifer (southwest Spain) illustrate the theoretical results of the study.

  20. Ultimate fate of constrained voters

    International Nuclear Information System (INIS)

    Vazquez, F; Redner, S

    2004-01-01

    We examine the ultimate fate of individual opinions in a socially interacting population of leftists, centrists and rightists. In an elemental interaction between agents, a centrist and a leftist can both become centrists or both become leftists with equal rates (and similarly for a centrist and a rightist). However leftists and rightists do not interact. This interaction step between pairs of agents is applied repeatedly until the system can no longer evolve. In the mean-field limit, we determine the exact probability that the system reaches consensus (either leftist, rightist or centrist) or a frozen mixture of leftists and rightists as a function of the initial composition of the population. We also determine the mean time until the final state is reached. Some implications of our results for the ultimate fate in a limit of the Axelrod model are discussed

  1. Ultimate fate of constrained voters

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez, F [Department of Physics, Center for BioDynamics, Boston University, Boston, MA 02215 (United States); Redner, S [Department of Physics, Center for Polymer Studies, Boston University, Boston, MA 02215 (United States)

    2004-09-03

    We examine the ultimate fate of individual opinions in a socially interacting population of leftists, centrists and rightists. In an elemental interaction between agents, a centrist and a leftist can both become centrists or both become leftists with equal rates (and similarly for a centrist and a rightist). However leftists and rightists do not interact. This interaction step between pairs of agents is applied repeatedly until the system can no longer evolve. In the mean-field limit, we determine the exact probability that the system reaches consensus (either leftist, rightist or centrist) or a frozen mixture of leftists and rightists as a function of the initial composition of the population. We also determine the mean time until the final state is reached. Some implications of our results for the ultimate fate in a limit of the Axelrod model are discussed.

  2. 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

  3. CAirTOX: A compartment model for assessing the fate of and human exposure to toxic-chemical emissions to air

    Energy Technology Data Exchange (ETDEWEB)

    McKone, T.E.

    1993-10-01

    CAirTOX has been developed as a spreadsheet model to assist in making a risk assessment of toxic air emissions. With CAirTOX, one can address how contaminants released to an air basin can lead to contamination of soil, food, surface water, and sediments. The modeling effort includes a multimedia transport and transformation model, exposure scenario models, and efforts to quantify uncertainty in multimedia, multiple-pathway exposure assessments. The multimedia transport and transformation model is a steady-state, but non-equilibrium model that can be used to assess concentrations of contaminants released continuously to air. In Part 1, the authors describe the multimedia transport and transformation model used to determine the fate of air emissions. In Part 2, they describe inputs and data needs for CAirTOX and the development of a set of landscape factors, which can be used to represent regional air basin/water-shed systems in California. In Part 3, they describe the multiple-pathway exposure scenarios and exposure algorithms. In Part 4, they compare the HRA approach and results and the CAirTOX exposure equations. In Part 5, they consider model sensitivity and uncertainty to determine how variability and uncertainty in model inputs affects the precision, accuracy, and credibility of the model output.

  4. Imaging long-term fate of intramyocardially implanted mesenchymal stem cells in a porcine myocardial infarction model.

    Directory of Open Access Journals (Sweden)

    Emerson C Perin

    Full Text Available The long-term fate of stem cells after intramyocardial delivery is unknown. We used noninvasive, repetitive PET/CT imaging with [(18F]FEAU to monitor the long-term (up to 5 months spatial-temporal dynamics of MSCs retrovirally transduced with the sr39HSV1-tk gene (sr39HSV1-tk-MSC and implanted intramyocardially in pigs with induced acute myocardial infarction. Repetitive [(18F]FEAU PET/CT revealed a biphasic pattern of sr39HSV1-tk-MSC dynamics; cell proliferation peaked at 33-35 days after injection, in periinfarct regions and the major cardiac lymphatic vessels and lymph nodes. The sr39HSV1-tk-MSC-associated [(18F]FEAU signals gradually decreased thereafter. Cardiac lymphography studies using PG-Gd-NIRF813 contrast for MRI and near-infrared fluorescence imaging showed rapid clearance of the contrast from the site of intramyocardial injection through the subepicardial lymphatic network into the lymphatic vessels and periaortic lymph nodes. Immunohistochemical analysis of cardiac tissue obtained at 35 and 150 days demonstrated several types of sr39HSV1-tk expressing cells, including fibro-myoblasts, lymphovascular cells, and microvascular and arterial endothelium. In summary, this study demonstrated the feasibility and sensitivity of [(18F]FEAU PET/CT imaging for long-term, in-vivo monitoring (up to 5 months of the fate of intramyocardially injected sr39HSV1-tk-MSC cells. Intramyocardially transplanted MSCs appear to integrate into the lymphatic endothelium and may help improve myocardial lymphatic system function after MI.

  5. Characterising the fate of nitrogenous waste from the sea-cage aquaculture of spiny lobsters using numerical modelling.

    Science.gov (United States)

    Lee, Soxi; Hartstein, Neil D; Jeffs, Andrew

    2015-06-01

    Although the aquaculture of spiny lobsters has been expanding since the 1970s, very little is known about the potential environmental impacts on water quality of this activity. This study quantified the production of dissolved inorganic nitrogen (DIN) from Australasian red spiny lobsters, Jasus edwardsii, in the laboratory, and these data were then used in a numerical model to predict the dispersal pattern of DIN from a hypothetical commercial spiny lobster farm for a coastal site where such a farm would typically be located. Modelling scenarios were set up with combinations of two different stocking densities (3 and 5 kg m(-3)), two different diets (mussels and moist artificial diet) and three different feed conversion ratios (FCR = 3, 5 and 28). DIN excretion rate from unfed lobsters in the laboratory on average was 1.10 ± 0.12 μg N g(-1) h(-1) while feeding lobsters on mussels and artificial diet increased DIN excretion significantly by around eightfold and twofold, respectively. Ammonia was consistently the dominant contributor to measured DIN output from lobsters. Modelling results indicated that the mean elevated DIN from a hypothetical farm where the lobsters were fed with mussels ranged from 7 up to 20 μg N L(-1) with increasing stocking density and FCR and was 30-150 % higher than the mean elevated DIN resulting from lobsters fed with artificial diet. Overall, the results indicated that DIN output from the hypothetical spiny lobster sea-cage farming is unlikely to be problematic using the FCR, stocking density, and the number of cages modelled at the coastal site in this study. Furthermore, feeding lobsters with artificial diet can help maintain a lower DIN output than seafood, such as mussels or trash fish.

  6. Environmental fate of Ra in cation-exchange regeneration brine waste disposed to septic tanks, New Jersey Coastal Plain, USA: migration to the water table.

    Science.gov (United States)

    Szabo, Zoltan; Jacobsen, Eric; Kraemer, Thomas F; Parsa, Bahman

    2010-01-01

    Fate of radium (Ra) in liquid regeneration brine wastes from water softeners disposed to septic tanks in the New Jersey Coastal Plain was studied. Before treatment, combined Ra ((226)Ra plus (228)Ra) concentrations (maximum, 1.54 Bq L(-1)) exceeded the 0.185 Bq L(-1) Maximum Contaminant Level in 4 of 10 studied domestic-well waters (median pH, 4.90). At the water table downgradient from leachfields, combined Ra concentrations were low (commonly 5.3, indicating sequestration; when pH was septic-tank effluents (maximum, 0.243 Bq L(-1))), indicating Ra mobilization from leachfield sediments. Confidence in quantification of Ra mass balance was reduced by study design limitations, including synoptic sampling of effluents and ground waters, and large uncertainties associated with analytical methods. The trend of Ra mobilization in acidic environments does match observations from regional water-quality assessments.

  7. A software engineering perspective on environmental modeling framework design: The object modeling system

    Science.gov (United States)

    The environmental modeling community has historically been concerned with the proliferation of models and the effort associated with collective model development tasks (e.g., code generation, data provisioning and transformation, etc.). Environmental modeling frameworks (EMFs) have been developed to...

  8. Fate of 14C-labelled compounds in marine environment

    International Nuclear Information System (INIS)

    Kale, S.P.; Raghu, K.; Sherkhane, P.D.; Murthy, N.B.K.

    1999-01-01

    Model ecosystems have played an important role in predicting environmental behavior of agrochemicals. The microcosms used in these studies generally include soil units containing usual biotic components common for that ecosystem. In present studies, scope of two such ecosystems has been extended to study the fate of 14 C-labelled pesticides in marine environment. 14 C-labelled pesticides used in these studies were chlorpyrifos, DDT and HCH. Two systems were developed in laboratory simulating marine environment to study the fate of these pesticides. The first system was developed in an all glass aquarium tank with marine sediments, seawater, clams and algae and is referred to as marine ecosystem. The second system was developed to permit the total 14 C-mass balance studies. It contained marine sediments under moist (60% water holding capacity) or flooded conditions and it is referred to as continuous flow system. Fate of 14 C-DDT was studied in marine ecosystem while degradation of 14 C-chlorpyrifos and 14 C-HCH was studied in continuous flow system. 14 C-DDT did not bioaccumulate in clams while at the end of 60 days 50% of the applied 14 C-activity was present in sediment fraction of marine ecosystem. 14 C-HCH degradation showed about 22-26% mineralization while 45-55% of the applied activity was recovered as organic volatiles. No significant bound residues were formed. 14 C-chorpyrifos underwent considerable degradation in marine environment. TCP was the major degradation product. (author)

  9. Modeling approaches for characterizing and evaluating environmental exposure to engineered nanomaterials in support of risk-based decision making.

    Science.gov (United States)

    Hendren, Christine Ogilvie; Lowry, Michael; Grieger, Khara D; Money, Eric S; Johnston, John M; Wiesner, Mark R; Beaulieu, Stephen M

    2013-02-05

    As the use of engineered nanomaterials becomes more prevalent, the likelihood of unintended exposure to these materials also increases. Given the current scarcity of experimental data regarding fate, transport, and bioavailability, determining potential environmental exposure to these materials requires an in depth analysis of modeling techniques that can be used in both the near- and long-term. Here, we provide a critical review of traditional and emerging exposure modeling approaches to highlight the challenges that scientists and decision-makers face when developing environmental exposure and risk assessments for nanomaterials. We find that accounting for nanospecific properties, overcoming data gaps, realizing model limitations, and handling uncertainty are key to developing informative and reliable environmental exposure and risk assessments for engineered nanomaterials. We find methods suited to recognizing and addressing significant uncertainty to be most appropriate for near-term environmental exposure modeling, given the current state of information and the current insufficiency of established deterministic models to address environmental exposure to engineered nanomaterials.

  10. Predicting People's Environmental Behaviour: Theory of Planned Behaviour and Model of Responsible Environmental Behaviour

    Science.gov (United States)

    Chao, Yu-Long

    2012-01-01

    Using different measures of self-reported and other-reported environmental behaviour (EB), two important theoretical models explaining EB--Hines, Hungerford and Tomera's model of responsible environmental behaviour (REB) and Ajzen's theory of planned behaviour (TPB)--were compared regarding the fit between model and data, predictive ability,…

  11. Physical modelling and testing in environmental geotechnics

    International Nuclear Information System (INIS)

    Garnier, J.; Thorel, L.; Haza, E.

    2000-01-01

    The preservation of natural environment has become a major concern, which affects nowadays a wide range of professionals from local communities administrators to natural resources managers (water, wildlife, flora, etc) and, in the end, to the consumers that we all are. Although totally ignored some fifty years ago, environmental geotechnics has become an emergent area of study and research which borders on the traditional domains, with which the geo-technicians are confronted (soil and rock mechanics, engineering geology, natural and anthropogenic risk management). Dedicated to experimental approaches (in-situ investigations and tests, laboratory tests, small-scale model testing), the Symposium fits in with the geotechnical domains of environment and transport of soil pollutants. These proceedings report some progress of developments in measurement techniques and studies of transport of pollutants in saturated and unsaturated soils in order to improve our understanding of such phenomena within multiphase environments. Experimental investigations on decontamination and isolation methods for polluted soils are discussed. The intention is to assess the impact of in-situ and laboratory tests, as well as small-scale model testing, on engineering practice. One paper is analysed in INIS data base for its specific interest in nuclear industry. The other ones, concerning the energy, are analyzed in ETDE data base

  12. Integrated Environmental Modelling: Human decisions, human challenges

    Science.gov (United States)

    Glynn, Pierre D.

    2015-01-01

    Integrated Environmental Modelling (IEM) is an invaluable tool for understanding the complex, dynamic ecosystems that house our natural resources and control our environments. Human behaviour affects the ways in which the science of IEM is assembled and used for meaningful societal applications. In particular, human biases and heuristics reflect adaptation and experiential learning to issues with frequent, sharply distinguished, feedbacks. Unfortunately, human behaviour is not adapted to the more diffusely experienced problems that IEM typically seeks to address. Twelve biases are identified that affect IEM (and science in general). These biases are supported by personal observations and by the findings of behavioural scientists. A process for critical analysis is proposed that addresses some human challenges of IEM and solicits explicit description of (1) represented processes and information, (2) unrepresented processes and information, and (3) accounting for, and cognizance of, potential human biases. Several other suggestions are also made that generally complement maintaining attitudes of watchful humility, open-mindedness, honesty and transparent accountability. These suggestions include (1) creating a new area of study in the behavioural biogeosciences, (2) using structured processes for engaging the modelling and stakeholder communities in IEM, and (3) using ‘red teams’ to increase resilience of IEM constructs and use.

  13. Physical modelling and testing in environmental geotechnics

    Energy Technology Data Exchange (ETDEWEB)

    Garnier, J.; Thorel, L.; Haza, E. [Laboratoire Central des Ponts et Chaussees a Nantes, 44 - Nantes (France)

    2000-07-01

    The preservation of natural environment has become a major concern, which affects nowadays a wide range of professionals from local communities administrators to natural resources managers (water, wildlife, flora, etc) and, in the end, to the consumers that we all are. Although totally ignored some fifty years ago, environmental geotechnics has become an emergent area of study and research which borders on the traditional domains, with which the geo-technicians are confronted (soil and rock mechanics, engineering geology, natural and anthropogenic risk management). Dedicated to experimental approaches (in-situ investigations and tests, laboratory tests, small-scale model testing), the Symposium fits in with the geotechnical domains of environment and transport of soil pollutants. These proceedings report some progress of developments in measurement techniques and studies of transport of pollutants in saturated and unsaturated soils in order to improve our understanding of such phenomena within multiphase environments. Experimental investigations on decontamination and isolation methods for polluted soils are discussed. The intention is to assess the impact of in-situ and laboratory tests, as well as small-scale model testing, on engineering practice. One paper has been analyzed in INIS data base for its specific interest in nuclear industry.

  14. Differential local tissue permissiveness influences the final fate of GPR17‐expressing oligodendrocyte precursors in two distinct models of demyelination

    Science.gov (United States)

    Coppolino, Giusy T.; Marangon, Davide; Negri, Camilla; Menichetti, Gianluca; Fumagalli, Marta; Gelosa, Paolo; Dimou, Leda; Furlan, Roberto; Lecca, Davide

    2018-01-01

    Abstract Promoting remyelination is recognized as a novel strategy to foster repair in neurodegenerative demyelinating diseases, such as multiple sclerosis. In this respect, the receptor GPR17, recently emerged as a new target for remyelination, is expressed by early oligodendrocyte precursors (OPCs) and after a certain differentiation stage it has to be downregulated to allow progression to mature myelinating oligodendrocytes. Here, we took advantage of the first inducible GPR17 reporter mouse line (GPR17‐iCreERT2xCAG‐eGFP mice) allowing to follow the final fate of GPR17+ cells by tamoxifen‐induced GFP‐labeling to unveil the destiny of these cells in two demyelination models: experimental autoimmune encephalomyelitis (EAE), characterized by marked immune cell activation and inflammation, and cuprizone induced demyelination, where myelin dysfunction is achieved by a toxic insult. In both models, demyelination induced a strong increase of fluorescent GFP+ cells at damaged areas. However, only in the cuprizone model reacting GFP+ cells terminally differentiated to mature oligodendrocytes, thus contributing to remyelination. In EAE, GFP+ cells were blocked at immature stages and never became myelinating oligodendrocytes. We suggest these strikingly distinct fates be due to different permissiveness of the local CNS environment. Based on previously reported GPR17 activation by emergency signals (e.g., Stromal Derived Factor‐1), we propose that a marked inflammatory milieu, such as that reproduced in EAE, induces GPR17 overactivation resulting in impaired downregulation, untimely and prolonged permanence in OPCs, leading, in turn, to differentiation blockade. Combined treatments with remyelinating agents and anti‐inflammatory drugs may represent new potential adequate strategies to halt neurodegeneration and foster recovery. PMID:29424466

  15. Experimental methodology for assessing the environmental fate of organic chemicals in polymer matrices using column leaching studies and OECD 308 water/sediment systems: Application to tire and road wear particles.

    Science.gov (United States)

    Unice, Kenneth M; Bare, Jennifer L; Kreider, Marisa L; Panko, Julie M

    2015-11-15

    Automobile tires require functional rubber additives including curing agents and antioxidants, which are potentially environmentally available from tire and road wear particles (TRWP) deposited in soil and sediment. A novel methodology was employed to evaluate the environmental fate of three commonly-used tire chemicals (N-cyclohexylbenzothiazole-2-sulfenamide (CBS), N-(1,3-dimethylbutyl)-N'-phenyl-1,4-phenylenediamine (6-PPD) and 1,3-diphenylguanidine (DPG)), using a road simulator, an artificial weathering chamber, column leaching tests, and OECD 308 sediment/water incubator studies. Environmental release factors were quantified for curing (f(C)), tire wear (f(W)), terrestrial weathering (f(S)), leaching from TRWP (f(L)), and environmental availability from TRWP (f(A)) by liquid chromatography-tandem mass spectroscopy (LC/MS/MS) analyses. Cumulative fractions representing total environmental availability (F(T)) and release to water (FR) were calculated for the tire chemicals and 13 transformation products. F(T) for CBS, DPG and 6-PPD inclusive of transformation products for an accelerated terrestrial aging time in soil of 0.1 years was 0.08, 0.1, and 0.06, respectively (equivalent to 6 to 10% of formulated mass). In contrast, a wider range of 5.5×10(-4) (6-PPD) to 0.06 (CBS) was observed for F(R) at an accelerated age of 0.1 years, reflecting the importance of hydrophobicity and solubility for determining the release to the water phase. Significant differences (p<0.05) in the weathering factor, f(S), were observed when chemicals were categorized by boiling point or hydrolysis rate constant. A significant difference in the leaching factor, f(L), and environmental availability factor, f(A), was also observed when chemicals were categorized by log K(ow). Our methodology should be useful for lifecycle analysis of other functional polymer chemicals. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Model Fusion Tool - the Open Environmental Modelling Platform Concept

    Science.gov (United States)

    Kessler, H.; Giles, J. R.

    2010-12-01

    The vision of an Open Environmental Modelling Platform - seamlessly linking geoscience data, concepts and models to aid decision making in times of environmental change. Governments and their executive agencies across the world are facing increasing pressure to make decisions about the management of resources in light of population growth and environmental change. In the UK for example, groundwater is becoming a scarce resource for large parts of its most densely populated areas. At the same time river and groundwater flooding resulting from high rainfall events are increasing in scale and frequency and sea level rise is threatening the defences of coastal cities. There is also a need for affordable housing, improved transport infrastructure and waste disposal as well as sources of renewable energy and sustainable food production. These challenges can only be resolved if solutions are based on sound scientific evidence. Although we have knowledge and understanding of many individual processes in the natural sciences it is clear that a single science discipline is unable to answer the questions and their inter-relationships. Modern science increasingly employs computer models to simulate the natural, economic and human system. Management and planning requires scenario modelling, forecasts and ‘predictions’. Although the outputs are often impressive in terms of apparent accuracy and visualisation, they are inherently not suited to simulate the response to feedbacks from other models of the earth system, such as the impact of human actions. Geological Survey Organisations (GSO) are increasingly employing advances in Information Technology to visualise and improve their understanding of geological systems. Instead of 2 dimensional paper maps and reports many GSOs now produce 3 dimensional geological framework models and groundwater flow models as their standard output. Additionally the British Geological Survey have developed standard routines to link geological

  17. A Survey of Precipitation Data for Environmental Modeling

    Science.gov (United States)

    This report explores the types of precipitation data available for environmental modeling. Precipitation is the main driver in the hydrological cycle and modelers use this information to understand water quality and water availability. Models use observed precipitation informatio...

  18. Coupling a continuous watershed-scale microbial fate and transport model with a stochastic dose-response model to estimate risk of illness in an urban watershed

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Hehuan, E-mail: hehuan86@vt.edu [Department of Biological Systems Engineering, Virginia Tech, 155 Ag Quad Lane, Blacksburg, VA 24061 (United States); Krometis, Leigh-Anne H. [Department of Biological Systems Engineering, Virginia Tech, 155 Ag Quad Lane, Blacksburg, VA 24061 (United States); Kline, Karen [Department of Biological Systems Engineering, Virginia Tech, 155 Ag Quad Lane, Blacksburg, VA 24061 (United States); Center for Watershed Studies, Virginia Tech, 155 Ag Quad Lane, Blacksburg, VA 24061 (United States)

    2016-05-01

    Within the United States, elevated levels of fecal indicator bacteria (FIB) remain the leading cause of surface water-quality impairments requiring formal remediation plans under the federal Clean Water Act's Total Maximum Daily Load (TMDL) program. The sufficiency of compliance with numerical FIB criteria as the targeted endpoint of TMDL remediation plans may be questionable given poor correlations between FIB and pathogenic microorganisms and varying degrees of risk associated with exposure to different fecal pollution sources (e.g. human vs animal). The present study linked a watershed-scale FIB fate and transport model with a dose-response model to continuously predict human health risks via quantitative microbial risk assessment (QMRA), for comparison to regulatory benchmarks. This process permitted comparison of risks associated with different fecal pollution sources in an impaired urban watershed in order to identify remediation priorities. Results indicate that total human illness risks were consistently higher than the regulatory benchmark of 36 illnesses/1000 people for the study watershed, even when the predicted FIB levels were in compliance with the Escherichia coli geometric mean standard of 126 CFU/100 mL. Sanitary sewer overflows were associated with the greatest risk of illness. This is of particular concern, given increasing indications that sewer leakage is ubiquitous in urban areas, yet not typically fully accounted for during TMDL development. Uncertainty analysis suggested the accuracy of risk estimates would be improved by more detailed knowledge of site-specific pathogen presence and densities. While previous applications of the QMRA process to impaired waterways have mostly focused on single storm events or hypothetical situations, the continuous modeling framework presented in this study could be integrated into long-term water quality management planning, especially the United States' TMDL program, providing greater clarity to

  19. Coupling a continuous watershed-scale microbial fate and transport model with a stochastic dose-response model to estimate risk of illness in an urban watershed

    International Nuclear Information System (INIS)

    Liao, Hehuan; Krometis, Leigh-Anne H.; Kline, Karen

    2016-01-01

    Within the United States, elevated levels of fecal indicator bacteria (FIB) remain the leading cause of surface water-quality impairments requiring formal remediation plans under the federal Clean Water Act's Total Maximum Daily Load (TMDL) program. The sufficiency of compliance with numerical FIB criteria as the targeted endpoint of TMDL remediation plans may be questionable given poor correlations between FIB and pathogenic microorganisms and varying degrees of risk associated with exposure to different fecal pollution sources (e.g. human vs animal). The present study linked a watershed-scale FIB fate and transport model with a dose-response model to continuously predict human health risks via quantitative microbial risk assessment (QMRA), for comparison to regulatory benchmarks. This process permitted comparison of risks associated with different fecal pollution sources in an impaired urban watershed in order to identify remediation priorities. Results indicate that total human illness risks were consistently higher than the regulatory benchmark of 36 illnesses/1000 people for the study watershed, even when the predicted FIB levels were in compliance with the Escherichia coli geometric mean standard of 126 CFU/100 mL. Sanitary sewer overflows were associated with the greatest risk of illness. This is of particular concern, given increasing indications that sewer leakage is ubiquitous in urban areas, yet not typically fully accounted for during TMDL development. Uncertainty analysis suggested the accuracy of risk estimates would be improved by more detailed knowledge of site-specific pathogen presence and densities. While previous applications of the QMRA process to impaired waterways have mostly focused on single storm events or hypothetical situations, the continuous modeling framework presented in this study could be integrated into long-term water quality management planning, especially the United States' TMDL program, providing greater clarity to watershed

  20. Assessment of climate change impact on the fates of polycyclic aromatic hydrocarbons in the multimedia environment based on model prediction.

    Science.gov (United States)

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

    2014-02-01

    The objective was to quantitatively understand the impacts of climate change (CC) under the A1B scenario on the contamination levels of 11 polycyclic aromatic hydrocarbons (PAHs) from pyrogenic sources in the environmental media based on model prediction. To predict the impacts of CC in South Korea, a revised version of KoEFT-PBTs, a dynamic multimedia model for persistent organic pollutants in South Korea, was used. Simulations were conducted for the period from 2000 to 2049 under the A1B scenario with the emission data for 2009 and the results for Seoul and Kangwon were compared to those under no climate change (NCC) scenario. Due to CC, the average of annual or monthly average concentration changes within a factor of two for the PAHs in air, soil and water. Time dependent comparison indicates that the maximum increase induced by CC in the monthly average concentration ranges from 10 to 10(2) in air and water. Change in advective flux due to wind speed difference between A1B and NCC dictates the change of the atmospheric PAHs levels while wet particle deposition due to rain rate difference contributes to some extent to the change of 5 and 6 ring PAHs. Whether the concentration change is positive or not depends primarily on the emission strength of internal sources relative to those in surrounding areas. The CC induced changes in atmospheric depositions and degradation rate in soil play a leading role in the change of soil concentration. In water, runoff and degradation are the key processes to the CC induced concentration change. Both in soil and water, the relative importance of individual key processes varies with PAHs. The difference between the two scenarios in wind speed and in rain rate shows stronger correlations with the concentration change than the temperature change. © 2013 Elsevier B.V. All rights reserved.

  1. 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)

    Maderich, V.; Bezhenar, R.; Heling, R.; With, G. de; Jung, K.T.; Myoung, J.G.; Cho, Y.-K.; Qiao, F.; Robertson, L.

    2014-01-01

    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 137 Cs data for the period 1945–2010. Calculated concentrations of 137 Cs 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 137 Cs 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

  2. National Environmental Policy Act guidance: A model process

    International Nuclear Information System (INIS)

    Angle, B.M.; Lockhart, V.A.T.; Sema, B.; Tuott, L.C.; Irving, J.S.

    1995-04-01

    The ''Model National Environmental Policy Act (NEPA) Process'' includes: References to regulations, guidance documents, and plans; training programs; procedures; and computer databases. Legislative Acts and reference documents from Congress, US Department of Energy, and Lockheed Idaho Technologies Company provide the bases for conducting NEPA at the Idaho National Engineering Laboratory (INEL). Lockheed Idaho Technologies Company (LITCO) NEPA / Permitting Department, the Contractor Environmental Organization (CEO) is responsible for developing and maintaining LITCO NEPA and permitting policies, guidance, and procedures. The CEO develops procedures to conduct environmental evaluations based on NEPA, Council on Environmental Quality (CEQ) regulations, and DOE guidance. This procedure includes preparation or support of environmental checklists, categorical exclusion determinations, environmental assessment determinations, environmental assessments, and environmental impact statements. In addition, the CEO uses this information to train personnel conducting environmental evaluations at the INEL. Streamlining these procedures fosters efficient use of resources, quality documents, and better decisions on proposed actions

  3. Title: Elucidation of Environmental Fate of Artificial Sweeteners (Aspartame, Acesulfame K and Saccharin) by Determining Bimolecular Rate Constants with Hydroxyl Radical at Various pH and Temperature Conditions and Possible Reaction By-Products

    Science.gov (United States)

    Teraji, T.; Arakaki, T.; Suzuka, T.

    2012-12-01

    Use of artificial sweeteners in beverages and food has been rapidly increasing because of their non-calorie nature. In Japan, aspartame, acesulfame K and sucralose are among the most widely used artificial sweeteners. Because the artificial sweeteners are not metabolized in human bodies, they are directly excreted into the environment without chemical transformations. We initiated a study to better understand the fate of artificial sweeteners in the marine environment. The hydroxyl radical (OH), the most potent reactive oxygen species, reacts with various compounds and determines the environmental oxidation capacity and the life-time of many compounds. The steady-state OH concentration and the reaction rate constants between the compound and OH are used to estimate the life-time of the compound. In this study, we determine the bimolecular rate constants between aspartame, acefulfame K and saccharin and OH at various pH and temperature conditions using a competition kinetics technique. We use hydrogen peroxide as a photochemical source of OH. Bimolecular rate constant we obtained so far for aspartame was (2.6±1.2)×109 M-1 s-1 at pH = 3.0 and (4.9±2.3)×109 M-1 s-1 at pH = 5.5. Little effect was seen by changing the temperatures between 15 and 40 oC. Activation energy (Ea) was calculated to be -1.0 kJ mol-1 at pH = 3.0, +8.5 kJ mol-1 at pH = 5.5, which could be regarded as zero. We will report bimolecular rate constants at different pHs and temperatures for acesulfame K and saccharin, as well. Possible reaction by-products for aspartame will be also reported. We will further discuss the fate of aspartame in the coastal environment.

  4. Comparison of Atmospheric Travel Distances of Several PAHs Calculated by Two Fate and Transport Models (The Tool and ELPOS with Experimental Values Derived from a Peat Bog Transect

    Directory of Open Access Journals (Sweden)

    Sabine Thuens

    2014-05-01

    Full Text Available Multimedia fate and transport models are used to evaluate the long range transport potential (LRTP of organic pollutants, often by calculating their characteristic travel distance (CTD. We calculated the CTD of several polycyclic aromatic hydrocarbons (PAHs and metals using two models: the OECD POV& LRTP Screening Tool (The Tool, and ELPOS. The absolute CTDs of PAHs estimated with the two models agree reasonably well for predominantly particle-bound congeners, while discrepancies are observed for more volatile congeners. We test the performance of the models by comparing the relative ranking of CTDs with the one of experimentally determined travel distances (ETDs. ETDs were estimated from historical deposition rates of pollutants to peat bogs in Eastern Canada. CTDs and ETDs of PAHs indicate a low LRTP. To eliminate the high influence on specific model assumptions and to emphasize the difference between the travel distances of single PAHs, ETDs and CTDs were analyzed relative to the travel distances of particle-bound compounds. The ETDs determined for PAHs, Cu, and Zn ranged from 173 to 321 km with relative uncertainties between 26% and 46%. The ETDs of two metals were shorter than those of the PAHs. For particle-bound PAHs the relative ETDs and CTDs were similar, while they differed for Chrysene.

  5. Estimating fate and transport of multiple contaminants in the vadose zone using a multi-layered soil column and three-phase equilibrium partitioning model

    International Nuclear Information System (INIS)

    Rucker, Gregory G.

    2007-01-01

    Soils at waste sites must be evaluated for the potential of residual soil contamination to leach and migrate to the groundwater beneath the disposal area. If migration to the aquifer occurs, contaminants can travel vast distances and pollute drinking water wells, thus exposing human receptors to harmful levels of toxins and carcinogens. To prevent groundwater contamination, a contaminant fate and transport analysis is necessary to assess the migration potential of residual soil contaminants. This type of migration analysis is usually performed using a vadose zone model to account for complex geotechnical and chemical variables including: decay processes, infiltration rate, soil properties, vadose zone thickness, and chemical behavior. The distinct advantage of using a complex model is that less restrictive, but still protective, soil threshold levels may be determined avoiding the unnecessary and costly remediation of marginally contaminated soils. However, the disadvantage of such modeling is the additional cost for data collection and labor required to apply these models. In order to allay these higher costs and to achieve a less restrictive but still protective clean-up level, a multiple contaminant and multi layered soil column equilibrium partitioning model was developed which is faster, simpler and less expensive to use. (authors)

  6. Cellular Models for Environmental Toxicant Biomarker Discovery

    National Research Council Canada - National Science Library

    Halverson, Kelly M; Lewsis, John A; Jackson, David A; Dennis, William; Brennan, Linda; Krakaner, Teresa

    2006-01-01

    ...) is the development of biomarkers of exposure, effect, and susceptibility. As exposure monitoring using environmental sampling equipment can be impractical and doesn't account for differences in individual responses, new methodologies must be sought...

  7. Advanced aviation environmental modeling tools to inform policymakers

    Science.gov (United States)

    2012-08-19

    Aviation environmental models which conform to international guidance have advanced : over the past several decades. Enhancements to algorithms and databases have increasingly : shown these models to compare well with gold standard measured data. The...

  8. Modelling consumers' preferences for Novel Protein Foods and environmental quality

    NARCIS (Netherlands)

    Zhu, X.; Ierland, van E.C.

    2005-01-01

    We develop a theoretical Applied General Equilibrium (AGE) model that explicitly includes the environmental input in production functions and the consumers' preferences for environmental quality in utility functions. We empirically apply the model to provide some insights into the effects of the

  9. EASETECH – A LCA model for assessment of environmental technologies

    DEFF Research Database (Denmark)

    Damgaard, Anders; Baumeister, Hubert; Astrup, Thomas Fruergaard

    2014-01-01

    EASETECH is a new model for the environmental assessment of environmental technologies developed in collaboration between DTU Environment and DTU Compute. EASETECH is based on experience gained in the field of waste management modelling over the last decade and applies the same concepts to systems...

  10. Data Sources Available for Modeling Environmental Exposures in Older Adults

    Science.gov (United States)

    This report, “Data Sources Available for Modeling Environmental Exposures in Older Adults,” focuses on information sources and data available for modeling environmental exposures in the older U.S. population, defined here to be people 60 years and older, with an emphasis on those...

  11. Numerical modelling for quantitative environmental risk assessment for the disposal of drill cuttings and mud

    Science.gov (United States)

    Wahab, Mohd Amirul Faiz Abdul; Shaufi Sokiman, Mohamad; Parsberg Jakobsen, Kim

    2017-10-01

    To investigate the fate of drilling waste and their impacts towards surrounding environment, numerical models were generated using an environmental software; MIKE by DHI. These numerical models were used to study the transportation of suspended drill waste plumes in the water column and its deposition on seabed in South China Sea (SCS). A random disposal site with the model area of 50 km × 25 km was selected near the Madalene Shoal in SCS and the ambient currents as well as other meteorological conditions were simulated in details at the proposed location. This paper was focusing on sensitivity study of different drill waste particle characteristics on impacts towards marine receiving environment. The drilling scenarios were obtained and adapted from the oil producer well at offshore Sabah (Case 1) and data from actual exploration drilling case at Pumbaa location (PL 469) in the Norwegian Sea (Case 2). The two cases were compared to study the effect of different drilling particle characteristics and their behavior in marine receiving environment after discharged. Using the Hydrodynamic and Sediment Transport models simulated in MIKE by DHI, the variation of currents and the behavior of the drilling waste particles can be analyzed and evaluated in terms of multiple degree zones of impacts.

  12. Modeling the long-term fate of agricultural nitrate in groundwater in the San Joaquin Valley, California

    Science.gov (United States)

    Chapelle, Francis H.; Campbell, Bruce G.; Widdowson, Mark A.; Landon, Mathew K.

    2013-01-01

    Nitrate contamination of groundwater systems used for human water supplies is a major environmental problem in many parts of the world. Fertilizers containing a variety of reduced nitrogen compounds are commonly added to soils to increase agricultural yields. But the amount of nitrogen added during fertilization typically exceeds the amount of nitrogen taken up by crops. Oxidation of reduced nitrogen compounds present in residual fertilizers can produce substantial amounts of nitrate which can be transported to the underlying water table. Because nitrate concentrations exceeding 10 mg/L in drinking water can have a variety of deleterious effects for humans, agriculturally derived nitrate contamination of groundwater can be a serious public health issue. The Central Valley aquifer of California accounts for 13 percent of all the groundwater withdrawals in the United States. The Central Valley, which includes the San Joaquin Valley, is one of the most productive agricultural areas in the world and much of this groundwater is used for crop irrigation. However, rapid urbanization has led to increasing groundwater withdrawals for municipal public water supplies. That, in turn, has led to concern about how contaminants associated with agricultural practices will affect the chemical quality of groundwater in the San Joaquin Valley. Crop fertilization with various forms of nitrogen-containing compounds can greatly increase agricultural yields. However, leaching of nitrate from soils due to irrigation has led to substantial nitrate contamination of shallow groundwater. That shallow nitrate-contaminated groundwater has been moving deeper into the Central Valley aquifer since the 1960s. Denitrification can be an important process limiting the mobility of nitrate in groundwater systems. However, substantial denitrification requires adequate sources of electron donors in order to drive the process. In many cases, dissolved organic carbon (DOC) and particulate organic carbon

  13. A mathematical model for environmental risk assessment in manufacturing industry

    Institute of Scientific and Technical Information of China (English)

    何莉萍; 徐盛明; 陈大川; 党创寅

    2002-01-01

    Environmental conscious manufacturing has become an important issue in industry because of market pressure and environmental regulations. An environmental risk assessment model was developed based on the network analytic method and fuzzy set theory. The "interval analysis method" was applied to deal with the on-site monitoring data as basic information for assessment. In addition, the fuzzy set theory was employed to allow uncertain, interactive and dynamic information to be effectively incorporated into the environmental risk assessment. This model is a simple, practical and effective tool for evaluating the environmental risk of manufacturing industry and for analyzing the relative impacts of emission wastes, which are hazardous to both human and ecosystem health. Furthermore, the model is considered useful for design engineers and decision-maker to design and select processes when the costs, environmental impacts and performances of a product are taken into consideration.

  14. Environmental Parametric Cost Model in Oil and Gas EPC Contracts

    Directory of Open Access Journals (Sweden)

    Madjid Abbaspour

    2018-01-01

    Full Text Available This study aims at identifying the parameters that govern the environmental costs in oil and gas projects. An initial conceptual model was proposed. Next, the costs of environmental management work packages were estimated, separately and were applied in project control tools (WBS/CBS. Then, an environmental parametric cost model was designed to determine the environmental costs and relevant weighting factors. The suggested model can be considered as an innovative approach to designate the environmental indicators in oil and gas projects. The validity of variables was investigated based on Delphi method. The results indicated that the project environmental management’s weighting factor is 0.87% of total project’s weighting factor.

  15. A Knowledge-Based Representation Scheme for Environmental Science Models

    Science.gov (United States)

    Keller, Richard M.; Dungan, Jennifer L.; Lum, Henry, Jr. (Technical Monitor)

    1994-01-01

    One of the primary methods available for studying environmental phenomena is the construction and analysis of computational models. We have been studying how artificial intelligence techniques can be applied to assist in the development and use of environmental science models within the context of NASA-sponsored activities. We have identified several high-utility areas as potential targets for research and development: model development; data visualization, analysis, and interpretation; model publishing and reuse, training and education; and framing, posing, and answering questions. Central to progress on any of the above areas is a representation for environmental models that contains a great deal more information than is present in a traditional software implementation. In particular, a traditional software implementation is devoid of any semantic information that connects the code with the environmental context that forms the background for the modeling activity. Before we can build AI systems to assist in model development and usage, we must develop a representation for environmental models that adequately describes a model's semantics and explicitly represents the relationship between the code and the modeling task at hand. We have developed one such representation in conjunction with our work on the SIGMA (Scientists' Intelligent Graphical Modeling Assistant) environment. The key feature of the representation is that it provides a semantic grounding for the symbols in a set of modeling equations by linking those symbols to an explicit representation of the underlying environmental scenario.

  16. MODEL OF IMPROVING ENVIRONMENTAL MANAGEMENT SYSTEM BY MULTI - SOFTWARE

    Directory of Open Access Journals (Sweden)

    Jelena Jovanovic

    2009-03-01

    Full Text Available This paper is based on doctoral dissertation which is oriented on improving environmental management system using multi - software. In this doctoral dissertation will be used key results of master thesis which is oriented on quantification environmental aspects and impacts by artificial neural network in organizations. This paper recommend improving environmental management system in organization using Balanced scorecard model and MCDM method - AHP (Analytic hierarchy process based on group decision. BSC would be spread with elements of Environmental management system and used in area of strategic management system in organization and AHP would be used in area of checking results getting by quantification environmental aspects and impacts.

  17. 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

  18. Estimating emissions of PFOS and PFOA to the Danube River catchment and evaluating them using a catchment-scale chemical transport and fate model

    International Nuclear Information System (INIS)

    Lindim, C.; Cousins, I.T.; Gils, J. van

    2015-01-01

    Novel approaches for estimating the emissions of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) to surface waters are explored. The Danube River catchment is used to investigate emissions contributing to riverine loads of PFOS and PFOA and to verify the accuracy of estimates using a catchment-scale dynamic fugacity-based chemical transport and fate model (STREAM-EU; Spatially and Temporally Resolved Exposure Assessment Model for European basins). Model accuracy evaluation performed by comparing STREAM-EU predicted concentrations and monitoring data for the Danube and its tributaries shows that the best estimates for PFOS and PFOA emissions in the Danube region are obtained by considering the combined contributions of human population, wealth (based on local gross domestic product (GDP)) and wastewater treatment. Human population alone cannot explain the levels of PFOS and PFOA found in the Danube catchment waters. Introducing wealth distribution information in the form of local GDPs improves emission estimates markedly, likely by better representing emissions resulting from consumer trends, industrial and commercial sources. For compounds such as PFOS and PFOA, whose main sink and transport media is the aquatic compartment, a major source to freshwater are wastewater treatment plants. Introducing wastewater treatment information in the emission estimations also further improves emission estimates. - Highlights: • Novel approaches for estimating PFOS/PFOA emissions to surface waters are explored. • Human population alone cannot explain the levels of PFOS/PFOA found in the Danube. • Best estimates are obtained when considering population, wealth and WWTP together.

  19. A review of mathematical models in economic environmental problems

    DEFF Research Database (Denmark)

    Nahorski, Z.; Ravn, H.F.

    2000-01-01

    The paper presents a review of mathematical models used,in economic analysis of environmental problems. This area of research combines macroeconomic models of growth, as dependent on capital, labour, resources, etc., with environmental models describing such phenomena like natural resources...... exhaustion or pollution accumulation and degradation. In simpler cases the models can be treated analytically and the utility function can be optimized using, e.g., such tools as the maximum principle. In more complicated cases calculation of the optimal environmental policies requires a computer solution....

  20. Proposing an Environmental Excellence Self-Assessment Model

    DEFF Research Database (Denmark)

    Meulengracht Jensen, Peter; Johansen, John; Wæhrens, Brian Vejrum

    2013-01-01

    that the EEA model can be used in global organizations to differentiate environmental efforts depending on the maturity stage of the individual sites. Furthermore, the model can be used to support the decision-making process regarding when organizations should embark on more complex environmental efforts......This paper presents an Environmental Excellence Self-Assessment (EEA) model based on the structure of the European Foundation of Quality Management Business Excellence Framework. Four theoretical scenarios for deploying the model are presented as well as managerial implications, suggesting...

  1. Considerations on the modelling of environmental radiocarbon

    International Nuclear Information System (INIS)

    Scott, E.M.; McCartney, M.

    1991-01-01

    Modelling radionuclide transfer within the natural environment involves three general steps: model formulation, its fitting using appropriate experimental data and model validation. The last process typically involves a sensitivity analysis and is used to modify model formulation and to direct future experimental effort. A wide variety of models exists appropriate to a number of different applications. Recently, attention has been directed to the development of principles for establishing local, regional and global upper bounds to doses. Here important considerations in model choice are the spatial detail required within the model, the links between models of differing resolution and the availability of suitable experimental data. We illustrate the model-building stages and discuss the above considerations in transfer modelling using radiocarbon which is produced and released as part of the nuclear fuel cycle. Its long half life of 5730 years, its mobility in the environment and its incorporation into man via the food chain make it of some considerable radiological significance. We consider local modelling of 14 C transfer using a Gaussian plume model, while its global dispersal is modelled using a large globally-averaged compartmental model. The global analysis is used to make short term predictions of 14 C specific activities to 2050 and longer-term predictions over a period of 10,000 years. We discuss the validation of these models and attempt to quantify the sources and magnitudes of the uncertainties in the model predictions. (26 refs., 2 figs.)

  2. The use of models to assess environmental impacts

    International Nuclear Information System (INIS)

    Gustafson, P.F.

    1978-01-01

    Environmental impacts will include the effects on man as well as on other major segments of the natural or indigenous ecosystems. In their present state of development, the models used for environmental impact analysis give at least a semiquantitative estimate of the magnitude of such impacts. The methods used in the development of models are given, and their strengths and weaknesses are described. The relationship between predictive, before-the-fact models, and monitoring programs conducted during facility operation are also discussed

  3. The influence of vertical sorbed phase transport on the fate of organic chemicals in surface soils.

    Science.gov (United States)

    McLachlan, Michael S; Czub, Gertje; Wania, Frank

    2002-11-15

    Gaseous exchange between surface soil and the atmosphere is an important process in the environmental fate of many chemicals. It was hypothesized that this process is influenced by vertical transport of chemicals sorbed to soil particles. Vertical sorbed phase transport in surface soils occurs by many processes such as bioturbation, cryoturbation, and erosion into cracks formed by soil drying. The solution of the advection/diffusion equation proposed by Jury et al. to describe organic chemical fate in a uniformly contaminated surface soil was modified to include vertical sorbed phase transport This process was modeled using a sorbed phase diffusion coefficient, the value of which was derived from soil carbon mass balances in the literature. The effective diffusivity of the chemical in a typical soil was greater in the modified model than in the model without sorbed phase transport for compounds with log K(OW) > 2 and log K(OA) > 6. Within this chemical partitioning space, the rate of volatilization from the surface soil was larger in the modified model than in the original model by up to a factor of 65. The volatilization rate was insensitive to the value of the sorbed phase diffusion coefficient throughout much of this chemical partitioning space, indicating that the surface soil layer was essentially well-mixed and that the mass transfer coefficient was determined by diffusion through the atmospheric boundary layer only. When this process was included in a non-steady-state regional multimedia chemical fate model running with a generic emissions scenario to air, the predicted soil concentrations increased by upto a factor of 25,whilethe air concentrations decreased by as much as a factor of approximately 3. Vertical sorbed phase transport in the soil thus has a major impact on predicted air and soil concentrations, the state of equilibrium, and the direction and magnitude of the chemical flux between air and soil. It is a key process influencing the environmental

  4. The application of DEA model in enterprise environmental performance auditing

    Science.gov (United States)

    Li, F.; Zhu, L. Y.; Zhang, J. D.; Liu, C. Y.; Qu, Z. G.; Xiao, M. S.

    2017-01-01

    As a part of society, enterprises have an inescapable responsibility for environmental protection and governance. This article discusses the feasibility and necessity of enterprises environmental performance auditing and uses DEA model calculate the environmental performance of Haier for example. The most of reference data are selected and sorted from Haier’s environmental reportspublished in 2008, 2009, 2011 and 2015, and some of the data from some published articles and fieldwork. All the calculation results are calculated by DEAP software andhave a high credibility. The analysis results of this article can give corporate managements an idea about using environmental performance auditing to adjust their corporate environmental investments capital quota and change their company’s environmental strategies.

  5. Use of a watershed model to characterize the fate and transport of fluometuron, a soil-applied cotton herbicide, in surface water

    Science.gov (United States)

    Coupe, R.H.

    2007-01-01

    The Soil and Water Assessment Tool (SWAT) was used to characterize the fate and transport of fluometuron (a herbicide used on cotton) in the Bogue Phalia Basin in northwestern Mississippi, USA. SWAT is a basin-scale watershed model, able to simulate hydrological, chemical, and sediment transport processes. After adjustments to a few parameters (specifically the SURLAG variable, the runoff curve number, Manning's N for overland flow, soil available water capacity, and the base-flow alpha factor) the SWAT model fit the observed streamflow well (the Coefficient of Efficiency and R2 were greater than 60). The results from comparing observed fluometuron concentrations with simulated concentrations were reasonable. The simulated concentrations (which were daily averages) followed the pattern of observed concentrations (instantaneous values) closely, but could be off in magnitude at times. Further calibration might have improved the fit, but given the uncertainties in the input data, it was not clear that any improvement would be due to a better understanding of the input variables. ?? 2007 Taylor & Francis.

  6. The on scene command and control system (OSC2) : an integrated incident command system (ICS) forms-database management system and oil spill trajectory and fates model

    International Nuclear Information System (INIS)

    Anderson, E.; Galagan, C.; Howlett, E.

    1998-01-01

    The On Scene Command and Control (OSC 2 ) system is an oil spill modeling tool which was developed to combine Incident Command System (ICS) forms, an underlying database, an integrated geographical information system (GIS) and an oil spill trajectory and fate model. The first use of the prototype OSC 2 system was at a PREP drill conducted at the U.S. Coast Guard Marine Safety Office, San Diego, in April 1998. The goal of the drill was to simulate a real-time response over a 36-hour period using the Unified Command System. The simulated spill was the result of a collision between two vessels inside San Diego Bay that caused the release of 2,000 barrels of fuel oil. The hardware component of the system which was tested included three notebook computers, two laser printers, and a poster printer. The field test was a success but it was not a rigorous test of the system's capabilities. The map display was useful in quickly setting up the ICS divisions and groups and in deploying resources. 6 refs., 1 tab., 5 figs

  7. PCPF-M model for simulating the fate and transport of pesticides and their metabolites in rice paddy field.

    Science.gov (United States)

    Boulange, Julien; Malhat, Farag; Thuyet, Dang Quoc; Watanabe, Hirozumi

    2017-12-01

    The PCPF-1 model was improved for forecasting the fate and transport of metabolites in addition to parent compounds in rice paddies. In the new PCPF-M model, metabolites are generated from the dissipation of pesticide applied in rice paddies through hydrolysis, photolysis and biological degradations. The methodology to parameterize the model was illustrated using two scenarios for which uncertainty and sensitivity analyses were also conducted. In a batch degradation experiment, the hourly forecasted concentrations of fipronil and its metabolites in paddy water were very accurate. In a field-scale experiment, the hourly forecasted concentrations of fipronil in paddy water and paddy soil were accurate while the corresponding daily forecasted concentrations of metabolites were adequate. The major contributors to the variation of the forecasted metabolite concentrations in paddy water and paddy soil were the formation fractions of the metabolites. The influence of uncertainty included in input parameters on the forecasted metabolite concentration was high during the peak concentration of metabolite in paddy water. In contrast, in paddy soil, the metabolite concentrations forecasted several days after the initial pesticide application were sensitive to the uncertainty incorporated in the input parameters. The PCPF-M model simultaneously forecasts the concentrations of a parent pesticide and up to three metabolites. The model was validated using fipronil and two of its metabolites in paddy water and paddy soil. The model can be used in the early stage of the pesticide registration process and in risk assessment analysis for the evaluation of pesticide exposure. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  8. Environmental problems and economic development in an endogenous fertility model

    OpenAIRE

    Frank Joest; Martin Quaas; Johannes Schiller

    2006-01-01

    Population growth is often viewed as a most oppressive global problem with respect to environmental deterioration, but the relationships between population development, economic dynamics and environmental pollution are complex due to various feedback mechanisms. We analyze society’s economic decisions on birth rates, investment into human and physical capital, and polluting emissions within an optimal control model of the coupled demographic-economic-environmental system. We show that a long-...

  9. The fate of pharmaceuticals and personal care products (PPCPs), endocrine disrupting contaminants (EDCs), metabolites and illicit drugs in a WWTW and environmental waters.

    Science.gov (United States)

    Archer, Edward; Petrie, Bruce; Kasprzyk-Hordern, Barbara; Wolfaardt, Gideon M

    2017-05-01

    A large number of emerging contaminants (ECs) are known to persist in surface waters, and create pressure on wastewater treatment works (WWTW) for their effective removal. Although a large database for the levels of these pollutants in water systems exist globally, there is still a lack in the correlation of the levels of these pollutants with possible long-term adverse health effects in wildlife and humans, such as endocrine disruption. The current study detected a total of 55 ECs in WWTW influent surface water, 41 ECs in effluent, and 40 ECs in environmental waters located upstream and downstream of the plant. A list of ECs persisted through the WWTW process, with 28% of all detected ECs removed by less than 50%, and 18% of all ECs were removed by less than 25%. Negative mass balances of some pharmaceuticals and metabolites were observed within the WWTW, suggesting possible back-transformation of ECs during wastewater treatment. Three parental illicit drug compounds were detected within the influent of the WWTW, with concentrations ranging between 27.6 and 147.0 ng L -1 for cocaine, 35.6-120.6 ng L -1 for mephedrone, and 270.9-450.2 ng L -1 for methamphetamine. The related environmental risks are also discussed for some ECs, with particular reference to their ability to disrupt endocrine systems. The current study propose the potential of the pharmaceuticals carbamazepine, naproxen, diclofenac and ibuprofen to be regarded as priority ECs for environmental monitoring due to their regular detection and persistence in environmental waters and their possible contribution towards adverse health effects in humans and wildlife. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. 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

  11. Characteristics and environmental fate of the anionic surfactant sodium lauryl ether sulphate (SLES) used as the main component in foaming agents for mechanized tunnelling

    International Nuclear Information System (INIS)

    Barra Caracciolo, Anna; Cardoni, Martina; Pescatore, Tanita; Patrolecco, Luisa

    2017-01-01

    The anionic surfactant sodium lauryl ether sulphate (SLES) is the main component of most commercial products used for soil conditioning in the excavation industry, in particular as lubricants for mechanized tunnelling. Its use during the excavation processes can result in either the subsequent possible re-use of the huge amount of soil debris as by-products (e.g. land covering) or its discharge as waste. Currently, there are neither SLES soil threshold limits in European legislation, nor comprehensive studies on the environmental risk for soil ecosystems in these exposure scenarios. In this context, the present paper reviews the available data on the intrinsic characteristics of persistence and the ecotoxicological effects of the anionic surfactant SLES. Although SLES is generally reported to be biodegradable in standard tests, with degradation rates between 7 h and 30 days, depending on the initial conditions, data on its biodegradation in environmental studies are quite scarce. Consequently, assessing SLES biodegradation rates in field conditions is crucial for evaluating if in residual concentrations (typically in the range 40–500 mg/kg in excavated soils) it can or not be a potential hazard for terrestrial and water organisms. Laboratory ecotoxicological tests pointed out detrimental effects of SLES for aquatic organisms, while data on the terrestrial species are rather poor so far and further studies at the expected environmental concentrations are necessary. Finally, the review reports the main analytical methods available for detecting anionic surfactants in solid matrices and the future research needed to improve knowledge on the possible environmental risks posed by the use of SLES in foaming agents for mechanized tunnelling. - Highlights: • Tons of excavated soil containing SLES are reused posing an environmental risk. • SLES can have detrimental effects on aquatic organisms exposed in lab test. • There is a need to improve knowledge on SLES

  12. Environmental Management Model for Road Maintenance Operation Involving Community Participation

    Science.gov (United States)

    Triyono, A. R. H.; Setyawan, A.; Sobriyah; Setiono, P.

    2017-07-01

    Public expectations of Central Java, which is very high on demand fulfillment, especially road infrastructure as outlined in the number of complaints and community expectations tweeter, Short Mail Massage (SMS), e-mail and public reports from various media, Highways Department of Central Java province requires development model of environmental management in the implementation of a routine way by involving the community in order to fulfill the conditions of a representative, may serve road users safely and comfortably. This study used survey method with SEM analysis and SWOT with Latent Independent Variable (X), namely; Public Participation in the regulation, development, construction and supervision of road (PSM); Public behavior in the utilization of the road (PMJ) Provincial Road Service (PJP); Safety in the Provincial Road (KJP); Integrated Management System (SMT) and latent dependent variable (Y) routine maintenance of the provincial road that is integrated with the environmental management system and involve the participation of the community (MML). The result showed the implementation of routine maintenance of road conditions in Central Java province has yet to implement an environmental management by involving the community; Therefore developed environmental management model with the results of H1: Community Participation (PSM) has positive influence on the Model of Environmental Management (MML); H2: Behavior Society in Jalan Utilization (PMJ) positive effect on Model Environmental Management (MML); H3: Provincial Road Service (PJP) positive effect on Model Environmental Management (MML); H4: Safety in the Provincial Road (KJP) positive effect on Model Environmental Management (MML); H5: Integrated Management System (SMT) has positive influence on the Model of Environmental Management (MML). From the analysis obtained formulation model describing the relationship / influence of the independent variables PSM, PMJ, PJP, KJP, and SMT on the dependent variable

  13. PEEX Modelling Platform for Seamless Environmental Prediction

    Science.gov (United States)

    Baklanov, Alexander; Mahura, Alexander; Arnold, Stephen; Makkonen, Risto; Petäjä, Tuukka; Kerminen, Veli-Matti; Lappalainen, Hanna K.; Ezau, Igor; Nuterman, Roman; Zhang, Wen; Penenko, Alexey; Gordov, Evgeny; Zilitinkevich, Sergej; Kulmala, Markku

    2017-04-01

    The Pan-Eurasian EXperiment (PEEX) is a multidisciplinary, multi-scale research programme stared in 2012 and aimed at resolving the major uncertainties in Earth System Science and global sustainability issues concerning the Arctic and boreal Northern Eurasian regions and in China. Such challenges include climate change, air quality, biodiversity loss, chemicalization, food supply, and the use of natural resources by mining, industry, energy production and transport. The research infrastructure introduces the current state of the art modeling platform and observation systems in the Pan-Eurasian region and presents the future baselines for the coherent and coordinated research infrastructures in the PEEX domain. The PEEX modeling Platform is characterized by a complex seamless integrated Earth System Modeling (ESM) approach, in combination with specific models of different processes and elements of the system, acting on different temporal and spatial scales. The ensemble approach is taken to the integration of modeling results from different models, participants and countries. PEEX utilizes the full potential of a hierarchy of models: scenario analysis, inverse modeling, and modeling based on measurement needs and processes. The models are validated and constrained by available in-situ and remote sensing data of various spatial and temporal scales using data assimilation and top-down modeling. The analyses of the anticipated large volumes of data produced by available models and sensors will be supported by a dedicated virtual research environment developed for these purposes.

  14. 1987 Oak Ridge model conference: Proceedings: Volume 2, Environmental protection

    International Nuclear Information System (INIS)

    1987-01-01

    See the abstract for Volume I for general information on the conference. Topics discussed in Volume II include data management techiques for environmental protection efforts, the use of models in environmental auditing, in emergency plans, chemical accident emergency response, risk assessment, monitoring of waste sites, air and water monitoring of waste sites, and in training programs

  15. 1987 Oak Ridge model conference: Proceedings: Volume 2, Environmental protection

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    See the abstract for Volume I for general information on the conference. Topics discussed in Volume II include data management techiques for environmental protection efforts, the use of models in environmental auditing, in emergency plans, chemical accident emergency response, risk assessment, monitoring of waste sites, air and water monitoring of waste sites, and in training programs. (TEM)

  16. LOUISIANA ENVIRONMENTAL MODELING SYSTEM FOR HYPOXIA RELATED ISSUES

    Science.gov (United States)

    An environmental assessment tool to evaluate the impacts of nonpoint source (NPS) pollutants discharged from Mississippi River basins into the Gulf of Mexico and to assess their effects on receiving water quality will be described. This system (Louisiana Environmental Modeling S...

  17. Modeling Environmental Literacy of Malaysian Pre-University Students

    Science.gov (United States)

    Shamuganathan, Sheila; Karpudewan, Mageswary

    2015-01-01

    In this study attempt was made to model the environmental literacy of Malaysian pre-university students enrolled in a matriculation college. Students enrolled in the matriculation colleges in Malaysia are the top notch students in the country. Environmental literacy of this group is perceived important because in the future these students will be…

  18. Frontier models for evaluating environmental efficiency: an overview

    NARCIS (Netherlands)

    Oude Lansink, A.G.J.M.; Wall, A.

    2014-01-01

    Our aim in this paper is to provide a succinct overview of frontier-based models used to evaluate environmental efficiency, with a special emphasis on agricultural activity. We begin by providing a brief, up-to-date review of the main approaches used to measure environmental efficiency, with

  19. USEtox fate and ecotoxicity factors for comparative assessment of toxic emissions in Life Cycle Analysis

    DEFF Research Database (Denmark)

    Andrew D, Henderson; Hauschild, Michael Zwicky; Van de Meent, Dik

    2011-01-01

    orders of magnitude. However, for an emission to air or soil, differences in chemical properties may decrease the CF by up to 10 orders of magnitude, as a result of intermedia transfer and degradation. This result brings new clarity to the relative contributions of fate and freshwater ecotoxicity...... with characteristic properties, this work provides understanding of the basis for calculations of CFs in USEtox. In addition, it offers insight into the chemical properties and critical mechanisms covering the continuum from chemical emission to freshwater ecosystem toxicity. For an emission directly to water......The USEtox model was developed in a scientific consensus process involving comparison of and harmonization between existing environmental multimedia fate models. For freshwater ecosystem toxicity, it covers the entire impact pathway, i.e., transforming a chemical emission into potential impacts...

  20. Radionuclide fate and effects

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    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

  1. Multiwalled Carbon Nanotube Deposition on Model Environmental Surfaces

    Science.gov (United States)

    Deposition of multiwalled carbon nanotubes (MWNTs) on model environmental surfaces was investigated using a quartz crystal microbalance with dissipation monitoring (QCM-D). Deposition behaviors of MWNTs on positively and negatively charged surfaces were in good agreement with Der...

  2. Assaying environmental nickel toxicity using model nematodes.

    Directory of Open Access Journals (Sweden)

    David Rudel

    Full Text Available Although nickel exposure results in allergic reactions, respiratory conditions, and cancer in humans and rodents, the ramifications of excess nickel in the environment for animal and human health remain largely undescribed. Nickel and other cationic metals travel through waterways and bind to soils and sediments. To evaluate the potential toxic effects of nickel at environmental contaminant levels (8.9-7,600 µg Ni/g dry weight of sediment and 50-800 µg NiCl2/L of water, we conducted assays using two cosmopolitan nematodes, Caenorhabditis elegans and Pristionchus pacificus. We assayed the effects of both sediment-bound and aqueous nickel upon animal growth, developmental survival, lifespan, and fecundity. Uncontaminated sediments were collected from sites in the Midwestern United States and spiked with a range of nickel concentrations. We found that nickel-spiked sediment substantially impairs both survival from larval to adult stages and adult longevity in a concentration-dependent manner. Further, while aqueous nickel showed no adverse effects on either survivorship or longevity, we observed a significant decrease in fecundity, indicating that aqueous nickel could have a negative impact on nematode physiology. Intriguingly, C. elegans and P. pacificus exhibit similar, but not identical, responses to nickel exposure. Moreover, P. pacificus could be tested successfully in sediments inhospitable to C. elegans. Our results add to a growing body of literature documenting the impact of nickel on animal physiology, and suggest that environmental toxicological studies could gain an advantage by widening their repertoire of nematode species.

  3. Assaying environmental nickel toxicity using model nematodes

    Science.gov (United States)

    Rudel, David; Douglas, Chandler; Huffnagle, Ian; Besser, John M.; Ingersoll, Christopher G.

    2013-01-01

    Although nickel exposure results in allergic reactions, respiratory conditions, and cancer in humans and rodents, the ramifications of excess nickel in the environment for animal and human health remain largely undescribed. Nickel and other cationic metals travel through waterways and bind to soils and sediments. To evaluate the potential toxic effects of nickel at environmental contaminant levels (8.9-7,600 µg Ni/g dry weight of sediment and 50-800 µg NiCl2/L of water), we conducted assays using two cosmopolitan nematodes, Caenorhabditis elegans and Pristionchus pacificus. We assayed the effects of both sediment-bound and aqueous nickel upon animal growth, developmental survival, lifespan, and fecundity. Uncontaminated sediments were collected from sites in the Midwestern United States and spiked with a range of nickel concentrations. We found that nickel-spiked sediment substantially impairs both survival from larval to adult stages and adult longevity in a concentration-dependent manner. Further, while aqueous nickel showed no adverse effects on either survivorship or longevity, we observed a significant decrease in fecundity, indicating that aqueous nickel could have a negative impact on nematode physiology. Intriguingly, C. elegansand P. pacificus exhibit similar, but not identical, responses to nickel exposure. Moreover, P. pacificus could be tested successfully in sediments inhospitable to C. elegans. Our results add to a growing body of literature documenting the impact of nickel on animal physiology, and suggest that environmental toxicological studies could gain an advantage by widening their repertoire of nematode species.

  4. Short- and medium-chain chlorinated paraffins in air and soil of subtropical terrestrial environment in the pearl river delta, South China: distribution, composition, atmospheric deposition fluxes, and environmental fate.

    Science.gov (United States)

    Wang, Yan; Li, Jun; Cheng, Zhineng; Li, Qilu; Pan, Xiaohui; Zhang, Ruijie; Liu, Di; Luo, Chunling; Liu, Xiang; Katsoyiannis, Athanasios; Zhang, Gan

    2013-03-19

    Research on the environmental fate of short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) in highly industrialized subtropical areas is still scarce. Air, soil, and atmospheric deposition process in the Pearl River Delta of South China were investigated, and the average SCCP and MCCP concentrations were 5.2 μg/sampler (17.69 ng/m(3)) and 4.1 μg/sampler for passive air samples, 18.3 and 59.3 ng/g for soil samples, and 5.0 and 5.3 μg/(m(2)d) for deposition samples, respectively. Influenced by primary sources and the properties of chlorinated paraffins (CPs), a gradient trend of concentrations and a fractionation of composition from more to less industrialized areas were discovered. Intense seasonal variations with high levels in summer air and winter deposition samples indicated that the air and deposition CP levels were controlled mainly by the vapor and particle phase, respectively. Complex environmental processes like volatilization and fractionation resulted in different CP profiles in different environment matrixes and sampling locations, with C(10-11) C(l6-7) and C(14) C(l6-7), C(10-12) C(l6-7) and C(14) C(l6-8), and C(11-12) C(l6-8) and C(14) C(l7-8) dominating in air, soil, and atmospheric deposition, respectively. Shorter-chain and less chlorinated congeners were enriched in air in the less industrialized areas, while longer-chain and higher chlorinated congeners were concentrated in soil in the more industrialized areas. This is suggesting that the gaseous transport of CPs is the dominant mechanism responsible for the higher concentrations of lighter and likely more mobile CPs in the rural areas.

  5. ENVIRONMENTAL RESPONSIBILITY MODEL BASED ON ISO 14000 MANAGEMENT SYSTEMS

    Directory of Open Access Journals (Sweden)

    Catalina SITNIKOV

    2012-01-01

    Full Text Available Worldwide corporations, as well as their stakeholders, are more conscious of the need for environmental management, SR behaviour, and sustainable growth and development. International Standards are becoming more significant for corporations to work towards common environmental management practices. ISO 14001 is the first and the broadest standard intended at a more responsible approach of corporations and the world’s most acknowledged framework for environmental management systems that assists corporations to better manage the effect of their activities on the environment. This article aims to study ISO 14001 implementation and its effects on the environmental responsibility. A model will be built, which covers the environmental management system, the components of organizational culture, being able to influence environmental standards implementation.

  6. Implementation of the Leaching Environmental Assessment Framework

    Science.gov (United States)

    New leaching tests are available in the U.S. for developing more accurate source terms for use in fate and transport models. For beneficial use or disposal, the use of the leaching environmental assessment framework (LEAF) will provide leaching results that reflect field condit...

  7. Models and parameters for environmental radiological assessments

    International Nuclear Information System (INIS)

    Miller, C.W.

    1984-01-01

    This book presents a unified compilation of models and parameters appropriate for assessing the impact of radioactive discharges to the environment. Models examined include those developed for the prediction of atmospheric and hydrologic transport and deposition, for terrestrial and aquatic food-chain bioaccumulation, and for internal and external dosimetry. Chapters have been entered separately into the data base

  8. Models and parameters for environmental radiological assessments

    Energy Technology Data Exchange (ETDEWEB)

    Miller, C W [ed.

    1984-01-01

    This book presents a unified compilation of models and parameters appropriate for assessing the impact of radioactive discharges to the environment. Models examined include those developed for the prediction of atmospheric and hydrologic transport and deposition, for terrestrial and aquatic food-chain bioaccumulation, and for internal and external dosimetry. Chapters have been entered separately into the data base. (ACR)

  9. 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 water resources to support operational and strategic risk assessments. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  10. STABILITY OF INTERNATIONAL ENVIRONMENTAL AGREEMENTS IN LEADERSHIP MODEL

    Institute of Scientific and Technical Information of China (English)

    Jin ZHANG; Shouyang WANG; Lei ZU

    2008-01-01

    International Environmental Agreements (IEAs) are a form of cooperation ratified by countries which can improve the management of shared environmental resources. The authors analyze the stability of International Environmental Agreements in leadership model. In 2006, Diamantoudi & Sartzetakis found that a stable coalition consists of either 2, 3, or 4 members if the number of countries is greater than 4. Their model is reconsidered. It is shown that the size of stable IEAs decreases from 3 to 2 when the total number of countries involved increases. However, a situation that can guarantee 4 to be the size of stable IEAs could not be found.

  11. Mathematical model in economic environmental problems

    Energy Technology Data Exchange (ETDEWEB)

    Nahorski, Z. [Polish Academy of Sciences, Systems Research Inst. (Poland); Ravn, H.F. [Risoe National Lab. (Denmark)

    1996-12-31

    The report contains a review of basic models and mathematical tools used in economic regulation problems. It starts with presentation of basic models of capital accumulation, resource depletion, pollution accumulation, and population growth, as well as construction of utility functions. Then the one-state variable model is discussed in details. The basic mathematical methods used consist of application of the maximum principle and phase plane analysis of the differential equations obtained as the necessary conditions of optimality. A summary of basic results connected with these methods is given in appendices. (au) 13 ills.; 17 refs.

  12. Simplifying modeling of nanoparticle aggregation-sedimentation behavior in environmental systems: A theoretical analysis

    NARCIS (Netherlands)

    Quik, J.T.K.; Meent, van de D.; Koelmans, A.A.

    2014-01-01

    Parameters and simplified model approaches for describing the fate of engineered nanoparticles (ENPs) are crucial to advance the risk assessment of these materials. Sedimentation behavior of ENPs in natural waters has been shown to follow apparent first order behavior, a ‘black box’ phenomenon that

  13. Capturing microbial sources distributed in a mixed-use watershed within an integrated environmental modeling workflow

    Science.gov (United States)

    Many watershed models simulate overland and instream microbial fate and transport, but few provide loading rates on land surfaces and point sources to the waterbody network. This paper describes the underlying equations for microbial loading rates associated with 1) land-applied ...

  14. Agricultural and Environmental Input Parameters for the Biosphere Model

    International Nuclear Information System (INIS)

    K. Rasmuson; K. Rautenstrauch

    2004-01-01

    This analysis is one of 10 technical reports that support the Environmental Radiation Model for Yucca Mountain Nevada (ERMYN) (i.e., the biosphere model). It documents development of agricultural and environmental input parameters for the biosphere model, and supports the use of the model to develop biosphere dose conversion factors (BDCFs). The biosphere model is one of a series of process models supporting the total system performance assessment (TSPA) for the repository at Yucca Mountain. The ERMYN provides the TSPA with the capability to perform dose assessments. A graphical representation of the documentation hierarchy for the ERMYN is presented in Figure 1-1. This figure shows the interrelationships between the major activities and their products (the analysis and model reports) that were planned in ''Technical Work Plan for Biosphere Modeling and Expert Support'' (BSC 2004 [DIRS 169573]). The ''Biosphere Model Report'' (BSC 2004 [DIRS 169460]) describes the ERMYN and its input parameters

  15. Application of a predictive Bayesian model to environmental accounting.

    Science.gov (United States)

    Anex, R P; Englehardt, J D

    2001-03-30

    Environmental accounting techniques are intended to capture important environmental costs and benefits that are often overlooked in standard accounting practices. Environmental accounting methods themselves often ignore or inadequately represent large but highly uncertain environmental costs and costs conditioned by specific prior events. Use of a predictive Bayesian model is demonstrated for the assessment of such highly uncertain environmental and contingent costs. The predictive Bayesian approach presented generates probability distributions for the quantity of interest (rather than parameters thereof). A spreadsheet implementation of a previously proposed predictive Bayesian model, extended to represent contingent costs, is described and used to evaluate whether a firm should undertake an accelerated phase-out of its PCB containing transformers. Variability and uncertainty (due to lack of information) in transformer accident frequency and severity are assessed simultaneously using a combination of historical accident data, engineering model-based cost estimates, and subjective judgement. Model results are compared using several different risk measures. Use of the model for incorporation of environmental risk management into a company's overall risk management strategy is discussed.

  16. Modelling the influence of intermittent rain events on long-term fate and transport of organic air pollutants

    DEFF Research Database (Denmark)

    Jolliet, Olivier; Hauschild, Michael Zwicky

    2005-01-01

    through wet deposition, and an underestimation of travel distances, leading to the following questions: How strong is the influence of the intermittent character of rain on concentrations, residence times, deposited fractions and characteristic transport distances of different substances in air......The deposition of particles and substances in air is under strong influence of the precipitation patterns of the atmosphere. Most multimedia models, like type III Mackay models, treat rain as a continuous phenomenon. This may cause severe overestimation of the substance removal from the atmosphere......? Is there an expression which can provide an accurate approximation to be used in steady state multimedia models? Assuming a periodically intermittent rain, the mass of an emitted substance which is present in the air compartment is calculated as a function of the deposition rate constants during dry and wet periods...

  17. Lumped parameter models for the interpretation of environmental tracer data

    International Nuclear Information System (INIS)

    Maloszewski, P.; Zuber, A.

    1996-01-01

    Principles of the lumped-parameter approach to the interpretation of environmental tracer data are given. The following models are considered: the piston flow model (PFM), exponential flow model (EM), linear model (LM), combined piston flow and exponential flow model (EPM), combined linear flow and piston flow model (LPM), and dispersion model (DM). The applicability of these models for the interpretation of different tracer data is discussed for a steady state flow approximation. Case studies are given to exemplify the applicability of the lumped-parameter approach. Description of a user-friendly computer program is given. (author). 68 refs, 25 figs, 4 tabs

  18. Lumped parameter models for the interpretation of environmental tracer data

    Energy Technology Data Exchange (ETDEWEB)

    Maloszewski, P [GSF-Inst. for Hydrology, Oberschleissheim (Germany); Zuber, A [Institute of Nuclear Physics, Cracow (Poland)

    1996-10-01

    Principles of the lumped-parameter approach to the interpretation of environmental tracer data are given. The following models are considered: the piston flow model (PFM), exponential flow model (EM), linear model (LM), combined piston flow and exponential flow model (EPM), combined linear flow and piston flow model (LPM), and dispersion model (DM). The applicability of these models for the interpretation of different tracer data is discussed for a steady state flow approximation. Case studies are given to exemplify the applicability of the lumped-parameter approach. Description of a user-friendly computer program is given. (author). 68 refs, 25 figs, 4 tabs.

  19. Model of environmental management system for environmentally sustainable universities training in Colombia

    International Nuclear Information System (INIS)

    Rivas Marin, Maria Isabel

    2011-01-01

    Sustainable campuses have become one of the main objectives of the Agendas University as a result of the impacts generated by the activities developed there and affect the environment. Given this, there are environmental management systems which are the set of practices, procedures, processes and resources needed to meet environmental regulations on business and are focused on reducing the impacts on the environment and the efficiency of processes. College- level companies still being considered, these systems do not work efficiently, it is necessary and urgent that the adequacy of a model environmental management system and that, through education and research, will help society to achieve the transition to sustainable lifestyles.

  20. A review of environmental fate, body burdens, and human health risk assessment of PCDD/Fs at two typical electronic waste recycling sites in China

    International Nuclear Information System (INIS)

    Chan, Janet Kit Yan; Wong, Ming H.

    2013-01-01

    This paper reviews the levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in different environmental media, human body burdens and health risk assessment results at e-waste recycling sites in China. To provide an indication of the seriousness of the pollution levels in the e-waste recycling sites in China, the data are compared with guidelines and available existing data for other areas. The comparison clearly shows that PCDD/Fs derived from the recycling processes lead to serious pollution in different environmental compartments (such as air, soil, sediment, dust and biota) and heavy body burdens. Of all kinds of e-waste recycling operations, open burning of e-waste and acid leaching activities are identified as the major sources of PCDD/Fs. Deriving from the published data, the estimated total exposure doses via dietary intake, inhalation, soil/dust ingestion and dermal contact are calculated for adults, children and breast-fed infants living in two major e-waste processing locations in China. The values ranged from 5.59 to 105.16 pg WHO-TEQ/kg bw/day, exceeding the tolerable daily intakes recommended by the WHO (1–4 pg WHO-TEQ/kg bw/day). Dietary intake is the most important exposure route for infants, children and adults living in these sites, contributing 60–99% of the total intakes. Inhalation is the second major exposure route, accounted for 12–30% of the total exposure doses of children and adults. In order to protect the environment and human health, there is an urgent need to control and monitor the informal e-waste recycling operations. Knowledge gaps, such as comprehensive dietary exposure data, epidemiological and clinical studies, body burdens of infants and children, and kinetics about PCDD/Fs partitions among different human tissues should be addressed. - Highlights: ► PCDD/F levels at e-waste recycling sites in China were reviewed. ► Data on environment and body burden and health risk assessment results were reviewed

  1. A review of environmental fate, body burdens, and human health risk assessment of PCDD/Fs at two typical electronic waste recycling sites in China

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Janet Kit Yan, E-mail: chanjky@hku.hk [School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong (China); Wong, Ming H., E-mail: mhwong@hkbu.edu.hk [Croucher Institute for Environmental Sciences, and Department of Biology, Hong Kong Baptist University, Hong Kong (China)

    2013-10-01

    This paper reviews the levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in different environmental media, human body burdens and health risk assessment results at e-waste recycling sites in China. To provide an indication of the seriousness of the pollution levels in the e-waste recycling sites in China, the data are compared with guidelines and available existing data for other areas. The comparison clearly shows that PCDD/Fs derived from the recycling processes lead to serious pollution in different environmental compartments (such as air, soil, sediment, dust and biota) and heavy body burdens. Of all kinds of e-waste recycling operations, open burning of e-waste and acid leaching activities are identified as the major sources of PCDD/Fs. Deriving from the published data, the estimated total exposure doses via dietary intake, inhalation, soil/dust ingestion and dermal contact are calculated for adults, children and breast-fed infants living in two major e-waste processing locations in China. The values ranged from 5.59 to 105.16 pg WHO-TEQ/kg bw/day, exceeding the tolerable daily intakes recommended by the WHO (1–4 pg WHO-TEQ/kg bw/day). Dietary intake is the most important exposure route for infants, children and adults living in these sites, contributing 60–99% of the total intakes. Inhalation is the second major exposure route, accounted for 12–30% of the total exposure doses of children and adults. In order to protect the environment and human health, there is an urgent need to control and monitor the informal e-waste recycling operations. Knowledge gaps, such as comprehensive dietary exposure data, epidemiological and clinical studies, body burdens of infants and children, and kinetics about PCDD/Fs partitions among different human tissues should be addressed. - Highlights: ► PCDD/F levels at e-waste recycling sites in China were reviewed. ► Data on environment and body burden and health risk assessment results were reviewed

  2. Environmental Warning System Based on the DPSIR Model: A Practical and Concise Method for Environmental Assessment

    Directory of Open Access Journals (Sweden)

    Wenqi Wang

    2018-05-01

    Full Text Available Though we are in urgent need of environmental warnings to slow environmental deterioration, currently, there is no internationally concise method for environmental warnings. In addition, the existing approaches do not combine the three aspects of ecology, resources, and environment. At the same time, the three elements of the environment (air, water, and soil are separated in most environmental warning systems. Thus, the method this paper gives is an innovative attempt and aims to make environmental assessment more practical. This paper establishes the index system of an environmental early warning based on the Driving–Pressure–State–Influence–Response (DPSIR model. The Analytic Hierarchy Process (AHP method was used to determine the weights. Next, single and integrated index methods further assess the environmental warning state, in which the weighted summation method is used to summarize the data and results. The case of Tianjin is used to confirm the applicability of this method. In conclusion, the method in this paper is more well-behaved and, therefore, more suitable to assist cities in their environmental assessment.

  3. Coupling model of energy consumption with changes in environmental utility

    International Nuclear Information System (INIS)

    He Hongming; Jim, C.Y.

    2012-01-01

    This study explores the relationships between metropolis energy consumption and environmental utility changes by a proposed Environmental Utility of Energy Consumption (EUEC) model. Based on the dynamic equilibrium of input–output economics theory, it considers three simulation scenarios: fixed-technology, technological-innovation, and green-building effect. It is applied to analyse Hong Kong in 1980–2007. Continual increase in energy consumption with rapid economic growth degraded environmental utility. First, energy consumption at fixed-technology was determined by economic outcome. In 1990, it reached a critical balanced state when energy consumption was 22×10 9 kWh. Before 1990 (x 1 9 kWh), rise in energy consumption improved both economic development and environmental utility. After 1990 (x 1 >22×10 9 kWh), expansion of energy consumption facilitated socio-economic development but suppressed environmental benefits. Second, technological-innovation strongly influenced energy demand and improved environmental benefits. The balanced state remained in 1999 when energy consumption reached 32.33×10 9 kWh. Technological-innovation dampened energy consumption by 12.99%, exceeding the fixed-technology condition. Finally, green buildings reduced energy consumption by an average of 17.5% in 1990–2007. They contributed significantly to energy saving, and buffered temperature fluctuations between external and internal environment. The case investigations verified the efficiency of the EUEC model, which can effectively evaluate the interplay of energy consumption and environmental quality. - Highlights: ► We explore relationships between metropolis energy consumption and environmental utility. ► An Environmental Utility of Energy Consumption (EUEC) model is proposed. ► Technological innovation mitigates energy consumption impacts on environmental quality. ► Technological innovation decreases demand of energy consumption more than fixed technology scenario

  4. Environmental indicators and international models for making decision

    International Nuclear Information System (INIS)

    Polanco, Camilo

    2006-01-01

    The last international features proposed by the Organization for Economic Cooperation Development (OECD) and United Nations (UN) are analyzed in the use of the environmental indicators, in typology, selection criteria, and models, for organizing the information for management, environmental performance, and decision making. The advantages and disadvantages of each model are analyzed, as well as their environmental index characteristics. The analyzed models are Pressure - State - Response (PSR) and its conceptual developments: Driving Force - State Response (DSR), Driving Force - Pressure - State - Impact - Response (DPSIR), Model- Flow-Quality (MFQ), Pressure - State - Impact - Effect - Response (PSIER), and, finally, Pressure-State - Impact - Effect - Response - Management (PSIERM). The use of one or another model will depend on the quality of the available information, as well as on the proposed objectives

  5. Modeling Influenza Transmission Using Environmental Parameters

    Science.gov (United States)

    Soebiyanto, Radina P.; Kiang, Richard K.

    2010-01-01

    Influenza is an acute viral respiratory disease that has significant mortality, morbidity and economic burden worldwide. It infects approximately 5-15% of the world population, and causes 250,000 500,000 deaths each year. The role of environments on influenza is often drawn upon the latitude variability of influenza seasonality pattern. In regions with temperate climate, influenza epidemics exhibit clear seasonal pattern that peak during winter months, but it is not as evident in the tropics. Toward this end, we developed mathematical model and forecasting capabilities for influenza in regions characterized by warm climate Hong Kong (China) and Maricopa County (Arizona, USA). The best model for Hong Kong uses Land Surface Temperature (LST), precipitation and relative humidity as its covariates. Whereas for Maricopa County, we found that weekly influenza cases can be best modelled using mean air temperature as its covariates. Our forecasts can further guides public health organizations in targeting influenza prevention and control measures such as vaccination.

  6. The fate of pelagic CaCO3 production in a high CO2 ocean: a model study

    Directory of Open Access Journals (Sweden)

    C. Ethe

    2007-07-01

    Full Text Available This model study addresses the change in pelagic calcium carbonate production (CaCO3, as calcite in the model and dissolution in response to rising atmospheric CO2. The parameterization of CaCO3 production includes a dependency on the saturation state of seawater with respect to calcite. It was derived from laboratory and mesocosm studies on particulate organic and inorganic carbon production in Emiliania huxleyi as a function of pCO2. The model predicts values of CaCO3 production and dissolution in line with recent estimates. The effect of rising pCO2 on CaCO3 production and dissolution was quantified by means of model simulations forced with atmospheric CO2 increasing at a rate of 1% per year from 286 ppm to 1144 ppm over a 140 year time-period. The simulation predicts a decrease of CaCO3 production by 27%. The combined change in production and dissolution of CaCO3 yields an excess uptake of CO2 from the atmosphere by the ocean of 5.9 GtC over the period of 140 years.

  7. Modeling the fate of nitrogen on the catchment scale using a spatially explicit hydro-biogeochemical simulation system

    Science.gov (United States)

    Klatt, S.; Butterbach-Bahl, K.; Kiese, R.; Haas, E.; Kraus, D.; Molina-Herrera, S. W.; Kraft, P.

    2015-12-01

    The continuous growth of the human population demands an equally growing supply for fresh water and food. As a result, available land for efficient agriculture is constantly diminishing which forces farmers to cultivate inferior croplands and intensify agricultural practices, e.g., increase the use of synthetic fertilizers. This intensification of marginal areas in particular will cause a dangerous rise in nitrate discharge into open waters or even drinking water resources. In order to reduce the amount of nitrate lost by surface runoff or lateral subsurface transport, bufferstrips have proved to be a valuable means. Current laws, however, promote rather static designs (i.e., width and usage) even though a multitude of factors, e.g., soil type, slope, vegetation and the nearby agricultural management, determines its effectiveness. We propose a spatially explicit modeling approach enabling to assess the effects of those factors on nitrate discharge from arable lands using the fully distributed hydrology model CMF coupled to the complex biogeochemical model LandscapeDNDC. Such a modeling scheme allows to observe the displacement of dissolved nutrients in both vertical and horizontal directions and serves to estimate both their uptake by the vegetated bufferstrip and loss to the environment. First results indicate a significant reduction of nitrate loss in the presence of a bufferstrip (2.5 m). We show effects induced by various buffer strip widths and plant cover on the nitrate retention.

  8. Assessing the fate of nutrients and carbon in the bioenergy chain through the modeling of biomass growth and conversion.

    Science.gov (United States)

    François, Jessica; Fortin, Mathieu; Patisson, Fabrice; Dufour, Anthony

    2014-12-02

    A forest growth model was coupled to a model of combined heat and power (CHP) pr