New insight into pesticide partition coefficient Kd for modelling pesticide fluvial transport: application to an agricultural catchment in south-western France.

PubMed

Boithias, Laurie; Sauvage, Sabine; Merlina, Georges; Jean, Séverine; Probst, Jean-Luc; Sánchez Pérez, José Miguel

2014-03-01

Pesticides applied on crops are leached with rainfall to groundwater and surface water. They threat the aquatic environment and may render water unfit for human consumption. Pesticide partitioning is one of the pesticide fate processes in the environment that should be properly formalised in pesticide fate models. Based on the analysis of 7 pesticide molecules (alachlor, atrazine, atrazine's transformation product deethylatrazine or DEA, isoproturon, tebuconazole and trifluralin) sampled from July 2009 to October 2010 at the outlet of the river Save (south-western France), the objectives of this study were (1) to check which of the environmental factors (discharge, pH, concentrations of total suspended matter (TSM), dissolved organic carbon (DOC) and particulate organic carbon (POC) could control the pesticide sorption dynamic, and (2) to establish a relationship between environmental factors, the partition coefficient Kd and the octanol/water distribution coefficient Kow. The comparison of physico-chemical parameters values during low flow and high flow shows that discharge, TSM and POC are the factors most likely controlling the pesticide sorption processes in the Save river network, especially for lower values of TSM (below 13mgL(-1)). We therefore express Kd depending on the widely literature-related variable Kow and on the commonly simulated variable TSM concentration. The equation can be implemented in any model describing the fluvial transport and fate of pesticides in both dissolved and sorbed phases, thus, Kd becomes a variable in time and space. The Kd calculation method can be applied to a wide range of catchments and organic contaminants. Copyright © 2013 Elsevier Ltd. All rights reserved.

A FUGACITY-BASED INDOOR RESIDENTIAL PESTICIDE FATE MODEL

EPA Science Inventory

Dermal and non-dietary pathways are potentially significant exposure pathways to pesticides used in the home. Exposure pathways include dermal contact of pesticide residues with the hands and skin, ingestion from hand-to-mouth activities, ingestion through contact with toys an...

Retention and Migration of Chlorpyrifos in Aquatic Sediments and Soils

NASA Astrophysics Data System (ADS)

Gebremariam, S. Y.; Beutel, M.; Yonge, D.; Flury, M.; Harsh, J. B.

2010-12-01

The accurate description of the fate and transport of potentially toxic agricultural pesticides in sediments and soils is of great interest to environmental scientists and regulators. Of particular concern is the widely documented detection of agricultural pesticides and their byproducts in drinking water wells. This presentation discusses results of a study of the fate and transport of chlorpyrifos, a strongly hydrophobic organophosphate-pesticide, in sediments and soils collected from a range of aquatic environments. Using radio-labeled chlorpyrifos, this study is unique in its comprehensive nature and focus on aquatic sediments, for which studies involving pesticide fate and transport are limited. Study components include: (1) batch equilibrium experiments to evaluate sorption/desorption parameters; (2) kinetic and non-equilibrium sorption experiments using miniaturized flow-cells; (3) column experiments to understand patterns of pesticide break through; and (4) numerical modeling of chlorpyrifos transport through aquatic sediments and soils. Initial results show that chlorpyrifos sorption, when corrected for reversible sorption to container walls, exhibited two component sorption, a large irreversible fraction and a smaller reversible fraction that can act as a secondary source. In addition, of a wide range of soil parameters measured, organic carbon content exhibited the highest correlation with chlorpyrifos retention in cranberry field soils. Simulation models developed in this study, which account for hysteretic and nonlinear sorption, will help to better predict the fate of chlorpyrifos and other hydrophobic chemicals in sediments and soils.

Fate and transport of dieldrin in coralville reservoir: residues in fish and water following a pesticide ban.

PubMed

Schnoor, J L

1981-02-20

A model for the fate and transport of pesticide has been calibrated with field data from 1968 to 1978. The results have aided in a management decision to lift a commercial fishing ban in Coralville Reservoir, eastern Iowa. Dieldrin residues in fish, sediment, and water are all declining at about 15 percent per year. Approximately 50 percent of the pesticide load is exported from the reservoir in the outflow, 40 percent undergoes sedimentation, and 10 percent enters the fish.

Comparison of predicted pesticide concentrations in groundwater from SCI-GROW and PRZM-GW models with historical monitoring data.

PubMed

Estes, Tammara L; Pai, Naresh; Winchell, Michael F

2016-06-01

A key factor in the human health risk assessment process for the registration of pesticides by the US Environmental Protection Agency (EPA) is an estimate of pesticide concentrations in groundwater used for drinking water. From 1997 to 2011, these estimates were obtained from the EPA empirical model SCI-GROW. Since 2012, these estimates have been obtained from the EPA deterministic model PRZM-GW, which has resulted in a significant increase in estimated groundwater concentrations for many pesticides. Historical groundwater monitoring data from the National Ambient Water Quality Assessment (NAWQA) Program (1991-2014) were compared with predicted groundwater concentrations from both SCI-GROW (v.2.3) and PRZM-GW (v.1.07) for 66 different pesticides of varying environmental fate properties. The pesticide environmental fate parameters associated with over- and underprediction of groundwater concentrations by the two models were evaluated. In general, SCI-GROW2.3 predicted groundwater concentrations were close to maximum historically observed groundwater concentrations. However, for pesticides with soil organic carbon content values below 1000 L kg(-1) and no simulated hydrolysis, PRZM-GW overpredicted, often by greater than 100 ppb. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

ORGANOPHOSPHATE PESTICIDE DEGRADATION UNDER DRINKING WATER TREATMENT CONDITIONS

EPA Science Inventory

Chlorpyrifos (CP) was used as a model compound to develop experimental methods and prototype modeling tools to forecast the fate of organophosphate (OP) pesticides under drinking water treatment conditions. CP was found to rapidly oxidize to chlorpyrifos oxon (CPO) in the presen...

Data worth and prediction uncertainty for pesticide transport and fate models in Nebraska and Maryland, United States

USGS Publications Warehouse

Nolan, Bernard T.; Malone, Robert W.; Doherty, John E.; Barbash, Jack E.; Ma, Liwang; Shaner, Dale L.

2015-01-01

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.

Water pollution: Pesticides in Aquatic environments. (Latest citations from Pollution abstracts). Published Search

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1993-01-01

The bibliography contains citations concerning the physicochemical and biochemical dynamics of pesticides in aquatic environments. The effects of organophosphorus, organochlorine, and arsenical pesticides on marine, surface, and groundwater ecosystems are discussed. Topics include biological fate and transformation of pesticides in waters, sources of release and transport of pesticides, bioaccumulation and metabolism of pesticides by aquatic organisms, ecological concentration and degradability of pesticides in model ecosystems, and marine ecology. Guidelines for pesticide registration and pesticide effluents are also referenced. (Contains a minimum of 205 citations and includes a subject term index and title list.)

MOLECULAR DYNAMICS MODELING OF SORPTION OF PESTICIDES ONTO THE SURFACES OF KAOLINITE

EPA Science Inventory

To accurately predict the fate of contaminants in the environment and to make sound decisions about environmental remediation, we must accurately understand sorption mechanisms and surface reactivity of environmental particles. Sorption of selected pesticides on kaolinite surface...

PRZM-3, A MODEL FOR PREDICTING PESTICIDE AND NITROGEN FATE IN THE CROP ROOT AND UNSATURATED SOIL ZONES: USER'S MANUAL FOR RELEASE 3.12.2

EPA Science Inventory

This publication contains documentation for the PRZM-3 model. PRZM-3 is the most recent version of a modeling system that links two subordinate models, PRZM and VADOFT, in order to predict pesticide transport and transformation down through the crop root and unsaturated soil zone...

Occurrence and fate of pesticides in four contrasting agricultural settings in the United States

USGS Publications Warehouse

Steele, G.V.; Johnson, H.M.; Sandstrom, M.W.; Capel, P.D.; Barbash, J.E.

2008-01-01

Occurrence and fate of 45 pesticides and 40 pesticide degradates were investigated in four contrasting agricultural settings—in Maryland, Nebraska, California, and Washington. Primary crops included corn at all sites, soybeans in Maryland, orchards in California and Washington, and vineyards in Washington. Pesticides and pesticide degradates detected in water samples from all four areas were predominantly from two classes of herbicides—triazines and chloroacetanilides; insecticides and fungicides were not present in the shallow ground water. In most samples, pesticide degradates greatly exceeded the concentrations of parent pesticide. In samples from Nebraska, the parent pesticide atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine] was about the same concentration as the degradate, but in samples from Maryland and California atrazine concentrations were substantially smaller than its degradate. Simazine [6-chloro-N,N′-diethyl-1,3,5-triazine-2,4-diamine], the second most detected triazine, was detected in ground water from Maryland, California, and Washington. Metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] rarely was detected without its degradates, and when they were detected in the same sample metolachlor always had smaller concentrations. The Root-Zone Water-Quality Model was used to examine the occurrence and fate of metolachlor at the Maryland site. Simulations accurately predicted which metolachlor degradate would be predominant in the unsaturated zone. In analyses of relations among redox indicators and pesticide variance, apparent age, concentrations of dissolved oxygen, and excess nitrogen gas (from denitrification) were important indicators of the presence and concentration of pesticides in these ground water systems.

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

USDA-ARS?s Scientific Manuscript database

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 ...

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

USDA-ARS?s Scientific Manuscript database

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 ev...

Heterogeneous photo-oxidation of pesticides and its implication to their environmental fate

NASA Astrophysics Data System (ADS)

Dubowski, Y.

2014-12-01

The environmental fate and impact of pesticides strongly depend on their post application degradation processes. While most existing knowledge on pesticides degradation refers to processes within bulk soil and water, applied pesticides may remain on treated surfaces (and on airborn particles) for long duration, exposed to atmospheric oxidants and solar radiation. The resulting photo-oxidation processes may have significant effect on their fate, especially in semiarid regions where pesticide applications take place during the long dry season and targeted irrigation is common. Here we present our studies on heterogeneous photo-oxidation of few commonly used pesticides (e.g., cypermethrin, methyl parathion, and chlorpyrifos), using novel laboratory setups enabling simultaneous monitoring of both phases. Experiments focused on kinetics, quantum yields, and identification of gaseous and condensed products. In addition, the reactivity of the selected pesticides was investigated as a function of their matrix (analytical vs. commercial formula), their phase (thin film vs. airborne aerosols), and the substrate they are sorbed on (leaf, soil, and glass). Complimentarily to these laboratory studies, field measurements of selected pesticides concentrations in few streams in northern Israel during the first rain events were also conducted and showed the important role of surface processes on these pesticides fate and transport in semi-arid climate.

Input dynamics of pesticide transformation products into surface water

NASA Astrophysics Data System (ADS)

Kern, Susanne; Singer, Heinz; Hollender, Juliane; Schwarzenbach, René P.; Fenner, Kathrin

2010-05-01

Some pesticide transformation products have been observed to occur in higher concentrations and more frequently than the parent active pesticide in surface water and groundwater. These products are often more mobile and sometimes more stable than the parent pesticide. If they also represent the major product into which the parent substance is transformed, these transformation products may dominate observed pesticide occurrences in surface water and groundwater. Their potential contribution to the overall risk to the aquatic environment caused by the use of the parent pesticide should therefore not be neglected in chemical risk and water quality assessments. The same is true for transformation products of other compound classes that might reach the soil environment, such as veterinary pharmaceuticals. However, the fate and input pathways of transformation products of soil-applied chemicals into surface water are not yet well understood, which largely prevents their appropriate inclusion into chemical risk and water quality assessments. Here, we studied whether prioritization methods based on available environmental fate data from pesticide registration dossiers in combination with basic fate models could help identify transformation products which can be found in relevant concentrations in surface and groundwater and which should therefore be included into monitoring programs. A three-box steady state model containing air, soil, and surface water compartments was used to predict relative inputs of pesticide transformation products into surface waters based on their physico-chemical and environmental fate properties. The model predictions were compared to monitoring data from a small Swiss river located in an intensely agricultural catchment (90 km2) which was flow-proportionally sampled from May to October 2008 and screened for 74 pesticides as well as 50 corresponding transformation products. Sampling mainly occurred during high discharge, but additional samples during baseflow conditions were also taken. The analytical measurements included solid phase extraction, liquid chromatography and high resolution mass spectrometry (SPE-LC-HR-MS/MS). Quantification was achieved using reference standards and internal standards. Besides the well-known transformation products of triazine and chloroacetanilide herbicides, transformation products of other compound classes such as azoxystrobin acid (from azoxystrobin, strobilurin fungicide), chloridazon-desphenyl and chloridazon-methyl-desphenyl (from chloridazon, pyridazinone herbicide), and metamitron-desamino (from metamitron, triazinone herbicide) were analyzed in surface water. For a selection of widely used pesticides in the catchment, modelled ratios of transformation product versus parent pesticide concentrations were compared to the measured concentration ratios in the river for the application period and for two 2-month periods following application. Concentration ratios agreed within a factor of 10 for all pairs of parent pesticides and transformation products, and for all seasons, with a single exception. The ratio of chloridazon-desphenyl to chloridazon was under-predicted by a factor of approximately 20. The data revealed that chloridazon-desphenyl was also found in elevated concentrations in all baseflow samples, indicating its presence in the groundwater component of the catchment. The same was true for other transformation products (e.g., metamitron-desamino, chloridazon-methly-desphenyl, metolachlor-ESA), but to a lesser degree. Based on baseflow separation of the hydrograph, the concentration ratio estimation model was supplemented with an additional baseflow component. The concentrations in the baseflow component were estimated with a simple leaching relationship that was compared against measured baseflow concentrations and groundwater findings in Switzerland. The final model yielded good agreement for all compounds and is therefore deemed suitable for prioritization of transformation products with a relevant exposure potential. It also clearly indicated the contribution of groundwater to the overall occurrence of pesticides and their transformation products in Swiss surface waters.

THE CHARACTERIZATION OF THE FATE AND TRANSPORT OF PESTICIDES IN AND AROUND BUILDINGS.

EPA Science Inventory

The Food Quality Protection Act (FQPA) of 1996 mandates consideration of aggregate exposures from food and non-occupational sources as part of EPA's pesticide evaluation process. In its implementation plan, EPA states that "EPA must develop new data and exposure models to estimat...

A fugacity-based indoor residential pesticide fate model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bennett, Deborah H.; Furtaw, Edward J.; McKone, Thomas E.

Dermal and non-dietary pathways are potentially significant exposure pathways to pesticides used in residences. Exposure pathways include dermal contact with residues on surfaces, ingestion from hand- and object-to-mouth activities, and absorption of pesticides into food. A limited amount of data has been collected on pesticide concentrations in various residential compartments following an application. But models are needed to interpret this data and make predictions about other pesticides based on chemical properties. In this paper, we propose a mass-balance compartment model based on fugacity principles. We include air (both gas phase and aerosols), carpet, smooth flooring, and walls as model compartments.more » Pesticide concentrations on furniture and toys, and in food, are being added to the model as data becomes available. We determine the compartmental fugacity capacity and mass transfer-rate coefficient for wallboard as an example. We also present the framework and equations needed for a dynamic mass-balance model.« less

ENANTIOMER-SPECIFIC FATE AND EFFECTS OF MODERN CHIRAL PESTICIDES

EPA Science Inventory

This slide presentation presents enantiomer-specific fate and effects of modern chiral pesticides. The research areas presented were analytical separation of enantiomers; environmental occurrence of enantiomers; transformation rates and enantioselectivity; bioaccumulation; and e...

Hydrogeologic setting and simulation of pesticide fate and transport in the unsaturated zone of a regolith-mantled, carbonate-rock terrain near Newville, Pennsylvania

USGS Publications Warehouse

Hippe, D.J.; Hall, D.W.

1996-01-01

Physical and chemical data were collected from May 1991 through April 1993 at a 4.5 hectare field site in Cumberland County, Pa., about 5 kilometers southeast of Newville. These data were used to define the hydrogeologic setting of a field site representative of the intensively farmed carbonate valleys of southeastern and south-central Pennsylvania. The environmental processing of commonly used pesticides (herbicides, fungicides, and insecticides) in the unsaturated zone was simulated with a process- oriented digital model to evaluate the environmental fate and transport of pesticides to ground water. Site data and modelling results provide a basis for a discussion of water-quality implications of agricultural best-management practices. The carbonate valleys of Pennsylvania comprise regolith-mantled carbonate-rock terrains that consist of broad undulating upland areas dissected by mostly dry valleys and widely spaced spring-fed creeks. The upland areas are farmed and exhibit possess a doline karst topography with many closed depressions, sinkholes, and bedrock outcrops. Unsaturated materials at the field site consist of an almost continuous soil cover composed of fine-grained residuum underlain by an intermediate vadose zone composed of karstified limestone. Soils are absent on scattered bedrock outcrops and are more than 12 meters thick in other areas of the site. The soil profile stores appreciable quantities of water with a volumetric average of about 36 percent water at field capacity. Organic carbon content of soil materials is about 1.7 percent in the Ap-horizon and from 0.1 to 0.3 percent throughout the full thickness of the B- and C-horizons. Atrazine, metolachlor, simazine, and the atrazine soil metabolites deethylatrazine and deisopropylatrazine were detected at concentrations above 0.05 mg/L in just the upper 0.6 meters of soil materials. However, detectable concentrations of atrazine, simazine, and atrazine soil metabolites were measured in water samples from lysimeters installed in soil materials at depths of 1.2, 2.1, and 3.7 meters and from monitor wells completed in the saturated zone to depths of 122 meters. Data collected from the field site were used to configure a pesticide screening model based on the pesticide version of the leaching estimation and chemistry model (LEACHP) developed by Wagenet and Hutson (1987). Model simulations show that most field-applied pesticides volatilize to the atmosphere, accumulate in soils, degrade in the subsurface environment, or leach to ground water. Model results were used to rank the leaching potentials of 66 pesticides. Eighteen of 32 herbicides, 4 of 9 fungicides, and 10 of 25 insecticides have moderate to large potential for leaching to ground water. A review of available pesticide monitoring data suggests that many compounds given moderate or high leaching potentials have not been tested for in ground water and the presence of pesticides in Pennsylvania's ground water may be underreported. Monitoring data do not exist for more than two-thirds of the pesticide compounds currently used in agricultural, carbonate areas of Pennsylvania. Knowledge of processes that govern fate and transport of pesticides is needed to facilitate development of effective pesticide best-management practices. In addition to comprehensive monitoring for pesticides and pesticide degradation products in ground water downgradient of areas of pesticide use, improved (1) characterization of unsaturated flow and transport through regolith mantled carbonate rocks, (2) estimates of pesticide degradation rates, (3) understanding of soil-property controls on pesticide movement, and (4) management models developed from process-oriented research would aid in understanding the processes.

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

EPA Pesticide Factsheets

Diffusive mass transfer at media interfaces exerts control on the fate and transport of pollutants originating from agricultural and urban landscapes and affects the con-ditions of water bodies. Diffusion is essentially a physical process affecting the distribution and fate of various environmental pollutants such as nutrients, pesticides, metals, PCBs, PAHs, etc. Environmental problems caused by excessive use of agricultural chemicals (e.g., pesticides and fertilizers) and improper discharge of industrial waste and fuel leaks are all influenced by the diffusive nature of pollutants in the environment. Eutrophication is one such environmental problem where the sediment-water interface exerts a significant physical and geochemical control on the eutrophic condition of the stressed water body. Exposure of streams and lakes to contaminated sediment is another common environmental problem whereby transport of the contaminant (PCBs, PAHs, and other organic contaminants) across the sediment water can increase the risk for exposure to the chemicals and pose a significant health hazard to aquatic life and human beings. This chapter presents analytical and numerical models describing fate and transport phenomena at the sediment-water interface in freshwater ecosystems, with the primary focus on nitrogen cycling and the applicability of the models to real-world environmental problems and challenges faced in their applications. The first model deals with nitrogen cycling

Identification of key climatic factors regulating the transport of pesticides in leaching and to tile drains.

PubMed

Nolan, Bernard T; Dubus, Igor G; Surdyk, Nicolas; Fowler, Hayley J; Burton, Aidan; Hollis, John M; Reichenberger, Stefan; Jarvis, Nicholas J

2008-09-01

Key climatic factors influencing the transport of pesticides to drains and to depth were identified. Climatic characteristics such as the timing of rainfall in relation to pesticide application may be more critical than average annual temperature and rainfall. The fate of three pesticides was simulated in nine contrasting soil types for two seasons, five application dates and six synthetic weather data series using the MACRO model, and predicted cumulative pesticide loads were analysed using statistical methods. Classification trees and Pearson correlations indicated that simulated losses in excess of 75th percentile values (0.046 mg m(-2) for leaching, 0.042 mg m(-2) for drainage) generally occurred with large rainfall events following autumn application on clay soils, for both leaching and drainage scenarios. The amount and timing of winter rainfall were important factors, whatever the application period, and these interacted strongly with soil texture and pesticide mobility and persistence. Winter rainfall primarily influenced losses of less mobile and more persistent compounds, while short-term rainfall and temperature controlled leaching of the more mobile pesticides. Numerous climatic characteristics influenced pesticide loss, including the amount of precipitation as well as the timing of rainfall and extreme events in relation to application date. Information regarding the relative influence of the climatic characteristics evaluated here can support the development of a climatic zonation for European-scale risk assessment for pesticide fate.

EXPOSURE ANALYSIS MODELING SYSTEM (EXAMS): USER MANUAL AND SYSTEM DOCUMENTATION

EPA Science Inventory

The Exposure Analysis Modeling System, first published in 1982 (EPA-600/3-82-023), provides interactive computer software for formulating aquatic ecosystem models and rapidly evaluating the fate, transport, and exposure concentrations of synthetic organic chemicals - pesticides, ...

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

NASA Astrophysics Data System (ADS)

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 intervention scenarios were explored (including changes to land use and pesticide usage) with the aim of providing a useful input to the debate between water companies, their regulators and pesticide users over the scale of catchment management required to support both DWD and WFD Article 7 compliance.

Fate of High Priority Pesticides During Drinking Water Treatment

EPA Science Inventory

The fate of organophosphorus (OP) pesticides in the presence of chlorinated oxidants was investigated under drinking water treatment conditions. In the presence of aqueous chlorine, intrinsic rate coefficients were found for the reaction of hypochlorous acid and hypochlorite ion ...

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

PubMed

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 <10%) and pesticide concentrations, although low sampling frequency in the larger catchments is likely to mask the true episodic nature of exposure. The computational efficiency of the model, along with the fact that most of its parameters can be derived from existing national soil property data mean that it can be used to rapidly predict pesticide exposure in multiple surface water resources to support operational and strategic risk assessments. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Pesticide regulations for agriculture: Chemically flawed regulatory practice.

PubMed

Gamble, Donald S; Bruccoleri, Aldo G

2016-08-02

Two categories of pesticide soil models now exist. Government regulatory agencies use pesticide fate and transport hydrology models, including versions of PRZM.gw. They have good descriptions of pesticide transport by water flow. Their descriptions of chemical mechanisms are unrealistic, having been postulated using the universally accepted but incorrect pesticide soil science. The objective of this work is to report experimental tests of a pesticide soil model in use by regulatory agencies and to suggest possible improvements. Tests with experimentally based data explain why PRZM.gw predictions can be wrong by orders of magnitude. Predictive spreadsheet models are the other category. They are experimentally based, with chemical stoichiometry applied to integral kinetic rate laws for sorption, desorption, intra-particle diffusion, and chemical reactions. They do not account for pesticide transport through soils. Each category of models therefore lacks what the other could provide. They need to be either harmonized or replaced. Some preliminary tests indicate that an experimental mismatch between the categories of models will have to be resolved. Reports of pesticides in the environment and the medical problems that overlap geographically indicate that government regulatory practice needs to account for chemical kinetics and mechanisms. Questions about possible cause and effect links could then be investigated.

Temporal-spatial patterns of three types of pesticide loadings in a middle-high latitude agricultural watershed.

PubMed

Ouyang, Wei; Cai, Guanqing; Tysklind, Mats; Yang, Wanyin; Hao, Fanghua; Liu, Hongbin

2017-10-01

Pesticide loadings to watersheds increase during agricultural development and may vary in accordance with different crop types and seasons. High pesticide loadings can potentially result in polluted stream water. The objective of this study was to determine the pesticide loadings and concentrations of three typical pesticides (atrazine, oxadiazon, and isoprothiolane) in river water from a middle-high latitude agricultural watershed in northern China. During this study, we evaluated the watershed pesticide loss patterns for two crop types over three decades. For this purpose, we integrated data from field investigations, laboratory experiments, and modeling simulations involving a distributed hydrological solute transport model (Soil and Water Assessment Tool, SWAT). SWAT was employed to compare the temporal-spatial fate and behaviors of atrazine, oxadiazon, and isoprothiolane from 1990 to 2014 in a watershed area amounting to 141.5 km 2 . The results showed that the three pesticides could be detected at different locations throughout the watershed, and isoprothiolane was detected at the maximum value of 1.082 μg/L in surface runoff of paddy land. The temporal trend for the yearly loading of atrazine decreased slightly over time, but the trends for oxadiazon and isoprothiolane increased markedly over an 18-year analysis period. In regard to the pesticide concentrations in water, atrazine was associated with the largest value of nearly 1.4 μg/L. July and August were the found to be prime periods for pesticide loss from paddy land, and the biggest monthly loss of atrazine from dryland appeared in June. Under similar usage conditions, isoprothiolane loading from paddy fields ranked as the largest one among the three types of pesticides and reached up to 17 g/ha. Limited monitoring data were useful for validating the model, which yielded valuable temporal-spatial data on the fate of pesticides in this watershed. With the expansion of paddy rice cultivation, risks for pesticide contamination of water bodies will increase. The results of this study should be valuable for future exposure and risk assessments aimed at protecting the environment and human health. Copyright © 2017 Elsevier Ltd. All rights reserved.

Response of macroinvertebrate communities to temporal dynamics of pesticide mixtures: A case study from the Sacramento River watershed, California.

PubMed

Chiu, Ming-Chih; Hunt, Lisa; Resh, Vincent H

2016-12-01

Pesticide pollution from agricultural field run-off or spray drift has been documented to impact river ecosystems worldwide. However, there is limited data on short- and long-term effects of repeated pulses of pesticide mixtures on biotic assemblages in natural systems. We used reported pesticide application data as input to a hydrological fate and transport model (Soil and Water Assessment Tool) to simulate spatiotemporal dynamics of pesticides mixtures in streams on a daily time-step. We then applied regression models to explore the relationship between macroinvertebrate communities and pesticide dynamics in the Sacramento River watershed of California during 2002-2013. We found that both maximum and average pesticide toxic units were important in determining impacts on macroinvertebrates, and that the compositions of macroinvertebrates trended toward taxa having higher resilience and resistance to pesticide exposure, based on the Species at Risk pesticide (SPEAR pesticides ) index. Results indicate that risk-assessment efforts can be improved by considering both short- and long-term effects of pesticide mixtures on macroinvertebrate community composition. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modelling the fate of pesticides in paddy rice-fish pond farming system in Northern Vietnam

NASA Astrophysics Data System (ADS)

Lamers, M.; Nguyen, N.; Streck, T.

2012-04-01

During the last decade rice production in Vietnam has tremendously increased due to the introduction of new high yield, short duration rice varieties and an increased application of pesticides. Since pesticides are toxic by design, there is a natural concern on the possible impacts of their presence in the environment on human health and environment quality. In North Vietnam, lowland and upland rice fields were identified to be a major non-point source of agrochemical pollution to surface and ground water, which are often directly used for domestic purposes. Field measurements, however, are time consuming, costly and logistical demanding. Hence, quantification, forecast and risk assessment studies are hampered by a limited amount of field data. One potential way to cope with this shortcoming is the use of process-based models. In the present study we developed a model for simulating short-term pesticide dynamics in combined paddy rice field - fish pond farming systems under the specific environmental conditions of south-east Asia. Basic approaches and algorithms to describe the key underlying biogeochemical processes were mainly adopted from the literature to assure that the model reflects the current standard of scientific knowledge and commonly accepted theoretical background. The model was calibrated by means of the Gauss-Marquardt-Levenberg algorithm and validated against measured pesticide concentrations (dimethoate and fenitrothion) during spring and summer rice crop season 2008, respectively, of a paddy field - fish pond system typical for northern Vietnam. First simulation results indicate that our model is capable to simulate the fate of pesticides in such paddy - fish pond farming systems. The model efficiency for the period of calibration, for example, was 0.97 and 0.95 for dimethoate and fenitrothion, respectively. For the period of validation, however, the modeling efficiency slightly decreased to 0.96 and 0.81 for dimethoate and fenitrothion, respectively. In our presentation we will picture key model features and algorithms and demonstrate that our model provides a useful and appropriate tool for analyzing and quantifying the transport and behavior of pesticides in paddy rice farming systems.

SCREENING MODEL FOR VOLATILE POLLUTANTS IN DUEL POROSITY SOILT

EPA Science Inventory

This paper develops mass fraction models for transport and fate of volatile organic chemicals, such as pesticides, in two-region soils. It addressed two main and interrelated parts. First, expressions are derived which describe the rate mass transfer coefficient in a periodical...

FATE & EFFECTS OF AGRICULTURAL PESTICIDES WITHIN WEEKS BAY WATERSHED, A NATIONAL ESTUARINE RESEARCH RESERVE

EPA Science Inventory

Lytle, J.S., T.F. Lytle and M.A. Lewis. In press. Fate and Effects of Agricultural Pesticides Within Weeks Bay Watershed, a National Estuarine Research Preserve. To be presented at the 24th Annual Meeting in North America of the Society of Environmental Toxicology and Chemistry: ...

Estimation of plant protection product application dates for environmental fate modeling based on phenological stages of crops.

PubMed

Gericke, Dirk; Nekovar, Jiri; Horold, Claudia

2010-10-01

According to the EU directive 91/414/EEC potential environmental concentrations of pesticides have to be assessed with environmental fate models. For the calculation of pesticide concentrations it is necessary to provide an application date which has to match the specific Biologische Bundesanstalt, Bundesamt, Chemische Industrie (BBCH) stage at which the pesticide shall be applied. If these application dates are not available for a specific stage, crop and country they must be estimated, which adds an additional uncertainty to the predicted concentrations. In the present study, we therefore evaluate to which extent application dates can be derived from phenological data. For this analysis phenological data, converted to BBCH stages, of two field crops provided by the German Weather Service (DWD) were analyzed. We found a linear correlation between BBCH stages and the respective appearance dates, which can be used for interpolation of appearance dates of specific BBCH stages. Remarkably, when comparing BBCH stages from Germany and the Czech Republic almost identical correlations of appearance dates and BBCH stages were found. In the next step, soil and climate data from Joint Research Centre (JRC) were analyzed together with phenological data in order to evaluate if BBCH stages can be estimated for countries with other climate or soil conditions. This analysis revealed that temperature, global radiation and evaporation were the parameters with the strongest impact. These parameters were used for estimating appearance dates of BBCH stages for other countries. Exemplarily, appearance dates for maize BBCH were calculated for Italy. Estimated and observed appearance dates showed a high concordance (on average six days difference). Finally, the political of impact a variation of a few days on calculated pesticide concentration was analyzed. Exemplarily, the pesticide fate model FOCUS PEARL was used to estimate pesticide groundwater concentrations. When calculating concentrations for application dates varying by ± two weeks, concentrations in groundwater usually varied very little. The highest variation was found for application at BBCH 30 in maize (6.6 % variation over all scenarios). These results showed that the uncertainty included in the estimation of appearance dates of BBCH stages for other countries has a relatively small effect on the results of PEARL and consequentially on the decision of the pesticide risk assessment by changing only the application date.

Fine scale spatial variability of microbial pesticide degradation in soil: scales, controlling factors, and implications

PubMed Central

Dechesne, Arnaud; Badawi, Nora; Aamand, Jens; Smets, Barth F.

2014-01-01

Pesticide biodegradation is a soil microbial function of critical importance for modern agriculture and its environmental impact. While it was once assumed that this activity was homogeneously distributed at the field scale, mounting evidence indicates that this is rarely the case. Here, we critically examine the literature on spatial variability of pesticide biodegradation in agricultural soil. We discuss the motivations, methods, and main findings of the primary literature. We found significant diversity in the approaches used to describe and quantify spatial heterogeneity, which complicates inter-studies comparisons. However, it is clear that the presence and activity of pesticide degraders is often highly spatially variable with coefficients of variation often exceeding 50% and frequently displays non-random spatial patterns. A few controlling factors have tentatively been identified across pesticide classes: they include some soil characteristics (pH) and some agricultural management practices (pesticide application, tillage), while other potential controlling factors have more conflicting effects depending on the site or the pesticide. Evidence demonstrating the importance of spatial heterogeneity on the fate of pesticides in soil has been difficult to obtain but modeling and experimental systems that do not include soil's full complexity reveal that this heterogeneity must be considered to improve prediction of pesticide biodegradation rates or of leaching risks. Overall, studying the spatial heterogeneity of pesticide biodegradation is a relatively new field at the interface of agronomy, microbial ecology, and geosciences and a wealth of novel data is being collected from these different disciplinary perspectives. We make suggestions on possible avenues to take full advantage of these investigations for a better understanding and prediction of the fate of pesticides in soil. PMID:25538691

USER MANUAL FOR EXPRESS, THE EXAMS-PRZM EXPOSURE SIMULATION SHELL

EPA Science Inventory

The Environmental Fate and Effects Division (EFED) of EPA's Office of Pesticide Programs(OPP) uses a suite of ORD simulation models for the exposure analysis portion of regulatory risk assessments. These models (PRZM, EXAMS, AgDisp) are complex, process-based simulation codes tha...

40 CFR 158.2084 - Experimental use permit biochemical pesticides nontarget organisms and environmental fate data...

Code of Federal Regulations, 2013 CFR

2013-07-01

... test notes are shown in paragraph (e) of this section. Table—EUP Biochemical Pesticides Nontarget... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Experimental use permit biochemical... FOR PESTICIDES Biochemical Pesticides § 158.2084 Experimental use permit biochemical pesticides...

40 CFR 158.2084 - Experimental use permit biochemical pesticides nontarget organisms and environmental fate data...

Code of Federal Regulations, 2011 CFR

2011-07-01

... test notes are shown in paragraph (e) of this section. Table—EUP Biochemical Pesticides Nontarget... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Experimental use permit biochemical... FOR PESTICIDES Biochemical Pesticides § 158.2084 Experimental use permit biochemical pesticides...

40 CFR 158.2084 - Experimental use permit biochemical pesticides nontarget organisms and environmental fate data...

Code of Federal Regulations, 2012 CFR

2012-07-01

... test notes are shown in paragraph (e) of this section. Table—EUP Biochemical Pesticides Nontarget... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Experimental use permit biochemical... FOR PESTICIDES Biochemical Pesticides § 158.2084 Experimental use permit biochemical pesticides...

40 CFR 158.2084 - Experimental use permit biochemical pesticides nontarget organisms and environmental fate data...

Code of Federal Regulations, 2014 CFR

2014-07-01

... test notes are shown in paragraph (e) of this section. Table—EUP Biochemical Pesticides Nontarget... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Experimental use permit biochemical... FOR PESTICIDES Biochemical Pesticides § 158.2084 Experimental use permit biochemical pesticides...

Transport and fate of nitrate and pesticides: Hydrogeology and riparian zone processes

USGS Publications Warehouse

Puckett, L.J.; Hughes, W.B.

2005-01-01

There is continuing concern over potential impacts of widespread application of nutrients and pesticides on ground- and surface-water quality. Transport and fate of nitrate and pesticides were investigated in a shallow aquifer and adjacent stream, Cow Castle Creek, in Orangeburg County, South Carolina. Pesticide and pesticide degradate concentrations were detected in ground water with greatest frequency and largest concentrations directly beneath and downgradient from the corn (Zea mays L.) field where they were applied. In almost all samples in which they were detected, concentrations of pesticide degradates greatly exceeded those of parent compounds, and were still present in ground waters that were recharged during the previous 18 yr. The absence of both parent and degradate compounds in samples collected from deeper in the aquifer suggests that this persistence is limited or that the ground water had recharged before use of the pesticide. Concentrations of NO3- in ground water decreased with increasing depth and age, but denitrification was not a dominant controlling factor. Hydrologic and chemical data indicated that ground water discharges to the creek and chemical exchange takes place within the upper 0.7 m of the streambed. Ground water had its greatest influence on surface-water chemistry during low-flow periods, causing a decrease in concentrations of Cl-, NO3-, pesticides, and pesticide degradates. Conversely, shallow subsurface drainage dominates stream chemistry during high-flow periods, increasing stream concentrations of Cl-, NO3-, pesticides, and pesticide degradates. These results point out the importance of understanding the hydrogeologic setting when investigating transport and fate of contaminants in ground water and surface water. ?? ASA, CSSA, SSSA.

An integrated model-based approach to the risk assessment of pesticide drift from vineyards

NASA Astrophysics Data System (ADS)

Pivato, Alberto; Barausse, Alberto; Zecchinato, Francesco; Palmeri, Luca; Raga, Roberto; Lavagnolo, Maria Cristina; Cossu, Raffaello

2015-06-01

The inhalation of pesticide in air is of particular concern for people living in close contact with intensive agricultural activities. This study aims to develop an integrated modelling methodology to assess whether pesticides pose a risk to the health of people living near vineyards, and apply this methodology in the world-renowned Prosecco DOCG (Italian label for protection of origin and geographical indication of wines) region. A sample field in Bigolino di Valdobbiadene (North-Eastern Italy) was selected to perform the pesticide fate modellization and the consequent inhalation risk assessment for people living in the area. The modellization accounts for the direct pesticide loss during the treatment of vineyards and for the volatilization from soil after the end of the treatment. A fugacity model was used to assess the volatilization flux from soil. The Gaussian puff air dispersion model CALPUFF was employed to assess the airborne concentration of the emitted pesticide over the simulation domain. The subsequent risk assessment integrates the HArmonised environmental Indicators for pesticide Risk (HAIR) and US-EPA guidelines. In this case study the modelled situation turned to be safe from the point of view of human health in the case of non-carcinogenic compounds, and additional improvements were suggested to further mitigate the effect of the most critical compound.

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

NASA Astrophysics Data System (ADS)

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.

Spatiotemporal sensitivity analysis of vertical transport of pesticides in soil

EPA Science Inventory

Environmental fate and transport processes are influenced by many factors. Simulation models that mimic these processes often have complex implementations, which can lead to over-parameterization. Sensitivity analyses are subsequently used to identify critical parameters whose un...

USE OF PBPK/PD MODELS AND FOLIAR TRANSFER COEFFICIENTS IN ASSESSING REENTRY INTO PESTICIDE TREATED CITRUS AND TURF

EPA Science Inventory

Physiologically based pharmacokinetic and pharmacodynamic (PBpK/PD) models describing the fate of dermally applied "C-ring labeled ethyl parathion and isofenphos and inhibition of H-esterases (acetyleholin-, butyrylcholine-and carboxyl-) by oxons in the rat were used in co...

Coupling HYDRUS-1D with ArcGIS to estimate pesticide accumulation and leaching risk on a regional basis.

PubMed

Anlauf, Ruediger; Schaefer, Jenny; Kajitvichyanukul, Puangrat

2018-07-01

HYDRUS-1D is a well-established reliable instrument to simulate water and pesticide transport in soils. It is, however, a point-specific model which is usually used for site-specific simulations. Aim of the investigation was the development of pesticide accumulation and leaching risk maps for regions combining HYDRUS-1D as a model for pesticide fate with regional data in a geographical information system (GIS). It was realized in form of a python tool in ArcGIS. Necessary high resolution local soil information, however, is very often not available. Therefore, worldwide interpolated 250-m-grid soil data (SoilGrids.org) were successfully incorporated to the system. The functionality of the system is shown by examples from Thailand, where example regions that differ in soil properties and climatic conditions were exposed in the model system to pesticides with different properties. A practical application of the system will be the identification of areas where measures to optimize pesticide use should be implemented with priority. Copyright © 2018 Elsevier Ltd. All rights reserved.

SPECIATION OF COMPLEX ORGANIC CONTAMINANTS IN WATER WITH RAMAN SPECTROSCOPY

EPA Science Inventory

Pesticides and industrial chemicals are typically complex organic molecules with multiple heteroatoms that can ionize, tautomerize, and form various types of hydrates in water. However, conceptual models for predicting the fate of these chemicals in the environment ignore these ...

40 CFR 161.202 - Purposes of the registration data requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... fate studies are used to: assess the toxicity to man through exposure of humans to pesticide residues... for humans, fish and wildlife, or plants are used to assess the potential hazard of pesticides to...) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR REGISTRATION OF ANTIMICROBIAL PESTICIDES Data Requirement Tables...

40 CFR 161.202 - Purposes of the registration data requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... fate studies are used to: assess the toxicity to man through exposure of humans to pesticide residues... for humans, fish and wildlife, or plants are used to assess the potential hazard of pesticides to...) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR REGISTRATION OF ANTIMICROBIAL PESTICIDES Data Requirement Tables...

40 CFR 161.202 - Purposes of the registration data requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... fate studies are used to: assess the toxicity to man through exposure of humans to pesticide residues... for humans, fish and wildlife, or plants are used to assess the potential hazard of pesticides to...) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR REGISTRATION OF ANTIMICROBIAL PESTICIDES Data Requirement Tables...

40 CFR 161.202 - Purposes of the registration data requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... fate studies are used to: assess the toxicity to man through exposure of humans to pesticide residues... for humans, fish and wildlife, or plants are used to assess the potential hazard of pesticides to...) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR REGISTRATION OF ANTIMICROBIAL PESTICIDES Data Requirement Tables...

Use-Exposure Relationships of Pesticides for Aquatic Risk Assessment

PubMed Central

Luo, Yuzhou; Spurlock, Frank; Deng, Xin; Gill, Sheryl; Goh, Kean

2011-01-01

Field-scale environmental models have been widely used in aquatic exposure assessments of pesticides. Those models usually require a large set of input parameters and separate simulations for each pesticide in evaluation. In this study, a simple use-exposure relationship is developed based on regression analysis of stochastic simulation results generated from the Pesticide Root-Zone Model (PRZM). The developed mathematical relationship estimates edge-of-field peak concentrations of pesticides from aerobic soil metabolism half-life (AERO), organic carbon-normalized soil sorption coefficient (KOC), and application rate (RATE). In a case study of California crop scenarios, the relationships explained 90–95% of the variances in the peak concentrations of dissolved pesticides as predicted by PRZM simulations for a 30-year period. KOC was identified as the governing parameter in determining the relative magnitudes of pesticide exposures in a given crop scenario. The results of model application also indicated that the effects of chemical fate processes such as partitioning and degradation on pesticide exposure were similar among crop scenarios, while the cross-scenario variations were mainly associated with the landscape characteristics, such as organic carbon contents and curve numbers. With a minimum set of input data, the use-exposure relationships proposed in this study could be used in screening procedures for potential water quality impacts from the off-site movement of pesticides. PMID:21483772

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

USGS Publications Warehouse

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.

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

NASA Astrophysics Data System (ADS)

Desmet, Nele; Seuntjens, Piet

2013-04-01

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

Influences of aquatic plants on the fate of the pyrethroid insecticide lambda-cyhalothrin in aquatic environments.

PubMed

Hand, L H; Kuet, S F; Lane, M C; Maund, S J; Warinton, J S; Hill, I R

2001-08-01

Aquatic exposure assessments for pesticides are generally based on laboratory studies performed in water alone or water sediment systems. Although aquatic macrophytes, which include a variety of bryophytes, macroalgae, and angiosperms, can be a significant component of many aquatic ecosystems, their impact on pesticide fate is generally not included in exposure assessments. To investigate the influence of aquatic plants on the fate and behavior of the pyrethroid insecticide lambda (lambda)-cyhalothrin, two laboratory experiments (to assess adsorption and degradation) and an indoor microcosm study (to assess fate under semirealistic conditions) were conducted. In the laboratory studies, adsorption to macrophytes was extensive and essentially irreversible, and degradation occurred rapidly by cleavage of the ester bond. In the indoor microcosm, which contained water, sediment, and macrophytes from a pond, degradation was also rapid, with DT50 and DT90 values of less than 3 and 19 h, respectively, for dissipation from the water column and of less than 3 and 56 h, respectively, for the whole system. For adsorptive and readily degraded pesticides like lambda-cyhalothrin, we conclude that macrophytes have considerable influence on fate and behavior in surface waters.

Selection of Worst-Case Pesticide Leaching Scenarios for Pesticide Registration

NASA Astrophysics Data System (ADS)

Vereecken, H.; Tiktak, A.; Boesten, J.; Vanderborght, J.

2010-12-01

The use of pesticides, fertilizers and manure in intensive agriculture may have a negative impact on the quality of ground- and surface water resources. Legislative action has been undertaken in many countries to protect surface and groundwater resources from contamination by surface applied agrochemicals. Of particular concern are pesticides. The registration procedure plays an important role in the regulation of pesticide use in the European Union. In order to register a certain pesticide use, the notifier needs to prove that the use does not entail a risk of groundwater contamination. Therefore, leaching concentrations of the pesticide need to be assessed using model simulations for so called worst-case scenarios. In the current procedure, a worst-case scenario represents a parameterized pesticide fate model for a certain soil and a certain time series of weather conditions that tries to represent all relevant processes such as transient water flow, root water uptake, pesticide transport, sorption, decay and volatilisation as accurate as possible. Since this model has been parameterized for only one soil and weather time series, it is uncertain whether it represents a worst-case condition for a certain pesticide use. We discuss an alternative approach that uses a simpler model that requires less detailed information about the soil and weather conditions but still represents the effect of soil and climate on pesticide leaching using information that is available for the entire European Union. A comparison between the two approaches demonstrates that the higher precision that the detailed model provides for the prediction of pesticide leaching at a certain site is counteracted by its smaller accuracy to represent a worst case condition. The simpler model predicts leaching concentrations less precise at a certain site but has a complete coverage of the area so that it selects a worst-case condition more accurately.

Enantiomer specific measurements of current-use pesticides in aquatic systems

EPA Science Inventory

Contrary to predictions, current-use pesticides are adversely affecting aquatic systems in both urban and agricultural watersheds, particularly in California. One possible divergence from fate and effect predictions is that some current-use pesticides are chiral molecules. Increa...

Sorption and desorption of indaziflam degradates in several agricultural soils

USDA-ARS?s Scientific Manuscript database

Processes regulating pesticide fate in the environment are influenced by the physicochemical properties of pesticides and soils. Sorption-desorption are important processes as they regulate movement of pesticides in soil. Although sorption-desorption is widely studied for herbicides, studies involvi...

Modeling the Impact of Heterogeneous Spatial Distribution of Soil Microbes on Pesticide Biodegradation at the Centimeter Scale

NASA Astrophysics Data System (ADS)

Babey, T.; De Dreuzy, J. R.; Pinheiro, M.; Garnier, P.; Vieublé-Gonod, L.; Rapaport, A.

2015-12-01

Micro-organisms and substrates may be heterogeneously distributed in soils. This repartition as well as transport mechanisms bringing them into contact are expected to impact the biodegradation rates. Pinheiro et al [2015] have measured in cm-large reconstructed soil cores the fate of an injection of 2,4-D pesticide for different injection conditions and initial distributions of soil pesticide degraders. Through the calibration of a reactive transport model of these experiments, we show that: i) biodegradation of diffusion-controlled pesticide fluxes is favored by a high Damköhler number (high reaction rate compared to flux rate); ii) abiotic sorption processes are negligible and do not interact strongly with biodegradation; iii) biodegradation is primarily governed by the initial repartition of pesticide and degraders for diffusion-controlled transport, as diffusion greatly limits the flux of pesticide reaching the microbial hotspot due to dilution. These results suggest that for biodegradation to be substantial, a spatial heterogeneity in the repartition of microbes and substrate has to be associated with intermittent and fast transport processes to mix them.

Can soil drying affect the sorption of pesticides in soil?

NASA Astrophysics Data System (ADS)

Chaplain, Véronique; Saint, Philippe; Mamy, Laure; Barriuso, Enrique

2010-05-01

The sorption of pesticides in soils mainly controls their further dispersion into the environment. Sorption is usually related to the physico-chemical properties of molecules but it also depends on the hydrophobic features of soils. However, the hydrophobicity of soils changes with wetting and drying cycles and this can be enhanced with climate change. The objective of this study was to measure by using controlled artificial soils the influence of the hydrophobic characteristic of soils on the retention of a model pesticide. Artificial soils consisted in silica particles covered by synthetic cationic polymers. Polymers were characterized by the molar ratio of monomers bearing an alkyl chain of 12C. Two polymers were used, with 20 and 80 % ratios, and the same degree of polymerization. In addition, porous and non-porous particles were used to study the accessibility notion and to measure the influence of diffusion on pesticide sorption kinetics. Lindane was chosen as model molecule because its adsorption is supposed mainly due to hydrophobic interactions. Results on polymers adsorption on silica showed that it was governed by electrostatic interactions, without any dependency of the hydrophobic ratio. Polymers covered the entire surface of porous particles. Kinetic measurements showed that lindane sorption was slowed in porous particles due to the molecular diffusion inside the microporosity. The adsorption of lindane on covered silica particles corresponded to a partition mechanism described by linear isotherms. The slope was determined by the hydrophobic ratio of polymers: the sorption of lindane was highest in the most hydrophobic artificial soil. As a result, modification in soil hydrophobicity, that can happen with climate change, might affect the sorption and the fate of pesticides. However additional experiments are needed to confirm these first results. Such artificial soils should be used as reference materials to compare the reactivity of pesticides, to identify the main adsorption mechanisms, and to study the effect of modifications in soil physico-chemical properties on the fate of pesticides.

78 FR 26935 - Data Requirements for Antimicrobial Pesticides

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-08

... human health, and environmental fate and effects of antimicrobial pesticide products. These revisions are also expected to help protect human health and the environment by providing an up-to-date... prevent the registration of pesticide products that may have unreasonable adverse effects on human health...

BIOACCUMULATION, BIOTRANSFORMATION, AND METABOLITE FORMATION OF FIPRONIL AND CHIRAL LEGACY PESTICIDES IN RAINBOW TROUT

EPA Science Inventory

To assess the fate of current-use pesticides it is important to understand their bioaccumulation and biotransformation by aquatic biota. We examined the dietary accumulation and enantioselective biotransformation of the chiral current-use pesticide fipronil, along with a mixture ...

Linking a one-dimensional pesticide fate model to a three-dimensional groundwater model to simulate pollution risks of shallow and deep groundwater underlying fractured till.

PubMed

Stenemo, Fredrik; Jørgensen, Peter R; Jarvis, Nicholas

2005-09-01

The one-dimensional pesticide fate model MACRO was loose-linked to the three-dimensional discrete fracture/matrix diffusion model FRAC3DVS to describe transport of the pesticide mecoprop in a fractured moraine till and local sand aquifer (5-5.5 m depth) overlying a regional limestone aquifer (16 m depth) at Havdrup, Denmark. Alternative approaches to describe the upper boundary in the groundwater model were examined. Field-scale simulations were run to compare a uniform upper boundary condition with a spatially variable upper boundary derived from Monte-Carlo simulations with MACRO. Plot-scale simulations were run to investigate the influence of the temporal resolution of the upper boundary conditions for fluxes in the groundwater model and the effects of different assumptions concerning the macropore/fracture connectivity between the two models. The influence of within-field variability of leaching on simulated mecoprop concentrations in the local aquifer was relatively small. A fully transient simulation with FRAC3DVS gave 20 times larger leaching to the regional aquifer compared to the case with steady-state water flow, assuming full connectivity with respect to macropores/fractures across the boundary between the two models. For fully transient simulations 'disconnecting' the macropores/fractures at the interface between the two models reduced leaching by a factor 24. A fully connected, transient simulation with FRAC3DVS, with spatially uniform upper boundary fluxes derived from a MACRO simulation with 'effective' parameters is therefore recommended for assessing leaching risks to the regional aquifer, at this, and similar sites.

Functional test of pedotransfer functions to predict water flow and solute transport with the dual-permeability model MACRO

NASA Astrophysics Data System (ADS)

Moeys, J.; Larsbo, M.; Bergström, L.; Brown, C. D.; Coquet, Y.; Jarvis, N. J.

2012-07-01

Estimating pesticide leaching risks at the regional scale requires the ability to completely parameterise a pesticide fate model using only survey data, such as soil and land-use maps. Such parameterisations usually rely on a set of lookup tables and (pedo)transfer functions, relating elementary soil and site properties to model parameters. The aim of this paper is to describe and test a complete set of parameter estimation algorithms developed for the pesticide fate model MACRO, which accounts for preferential flow in soil macropores. We used tracer monitoring data from 16 lysimeter studies, carried out in three European countries, to evaluate the ability of MACRO and this "blind parameterisation" scheme to reproduce measured solute leaching at the base of each lysimeter. We focused on the prediction of early tracer breakthrough due to preferential flow, because this is critical for pesticide leaching. We then calibrated a selected number of parameters in order to assess to what extent the prediction of water and solute leaching could be improved. Our results show that water flow was generally reasonably well predicted (median model efficiency, ME, of 0.42). Although the general pattern of solute leaching was reproduced well by the model, the overall model efficiency was low (median ME = -0.26) due to errors in the timing and magnitude of some peaks. Preferential solute leaching at early pore volumes was also systematically underestimated. Nonetheless, the ranking of soils according to solute loads at early pore volumes was reasonably well estimated (concordance correlation coefficient, CCC, between 0.54 and 0.72). Moreover, we also found that ignoring macropore flow leads to a significant deterioration in the ability of the model to reproduce the observed leaching pattern, and especially the early breakthrough in some soils. Finally, the calibration procedure showed that improving the estimation of solute transport parameters is probably more important than the estimation of water flow parameters. Overall, the results are encouraging for the use of this modelling set-up to estimate pesticide leaching risks at the regional-scale, especially where the objective is to identify vulnerable soils and "source" areas of contamination.

Assessing the fate of an aromatic hydrocarbon fluid in agricultural spray applications using the three-stage ADVOCATE model framework

USDA-ARS?s Scientific Manuscript database

Components of emulsifiable concentrates (ECs) used in pesticide formulations may be emitted to air following application in agricultural use and contribute to ozone formation. A key consideration is the fraction of the ECs that is volatilized. This study is designed to provide a mechanistic model fr...

MATHEMATICAL MODEL, SERATRA, FOR SEDIMENT-CONTAMINANT TRANSPORT IN RIVERS AND ITS APPLICATION TO PESTICIDE TRANSPORT IN FOUR MILE AND WOLF CREEKS IN IOWA

EPA Science Inventory

The sediment-contaminant transport model SERATRA was used as an integral part of the Chemical Migration and Risk Assessment (CMRA) Methodology, which simulates migration and fate of a contaminant over the land surface and in receiving streams, to assess potential short- and long-...

Pesticide exposure assessment for surface waters in the EU. Part 1: Some comments on the current procedure.

PubMed

Bach, Martin; Diesner, Mirjam; Großmann, Dietlinde; Guerniche, Djamal; Hommen, Udo; Klein, Michael; Kubiak, Roland; Müller, Alexandra; Priegnitz, Jan; Reichenberger, Stefan; Thomas, Kai; Trapp, Matthias

2016-07-01

In 2001, the European Commission introduced a risk assessment project known as FOCUS (FOrum for the Coordination of pesticide fate models and their USe) for the surface water risk assessment of active substances in the European Union. Even for the national authorisation of plant protection products (PPPs), the vast majority of EU member states still refer to the four runoff and six drainage scenarios selected by the FOCUS Surface Water Workgroup. However, our study, as well as the European Food Safety Authority (EFSA), has stated the need for various improvements. Current developments in pesticide exposure assessment mainly relate to two processes. Firstly, predicted environmental concentrations (PECs) of pesticides are calculated by introducing model input variables such as weather conditions, soil properties and substance fate parameters that have a probabilistic nature. Secondly, spatially distributed PECs for soil-climate scenarios are derived on the basis of an analysis of geodata. Such approaches facilitate the calculation of a spatiotemporal cumulative distribution function (CDF) of PECs for a given area of interest and are subsequently used to determine an exposure concentration endpoint as a given percentile of the CDF. For national PPP authorisation, we propose that, in the future, exposure endpoints should be determined from the overall known statistical PEC population for an area of interest, and derived for soil and climate conditions specific to the particular member state. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

77 FR 3621 - Rimsulfuron; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-25

... drinking water and in residential settings, but does not include occupational exposure. Section 408(b)(2)(C... PCT were assumed for all food commodities. 2. Dietary exposure from drinking water. The Agency used... in drinking water. These simulation models take into account data on the physical, chemical, and fate...

DETERMINATION OF TRANSFORMATION RATES OF CHIRAL PESTICIDES AND PCBS IN SOIL AND SEDIMENT MICROCOSMS

EPA Science Inventory

Risk Based Corrective Action (RBCA) has gained widespread acceptance as a favorable approach to remediating contaminated sites. The use of RBCA methods often requires computer-based modeling to assess the fate and transport of hazardous contaminants in subsurface environments, a...

Agrochemical fate models applied in agricultural areas from Colombia

NASA Astrophysics Data System (ADS)

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?

Sensitivity analysis of the STICS-MACRO model to identify cropping practices reducing pesticides losses.

PubMed

Lammoglia, Sabine-Karen; Makowski, David; Moeys, Julien; Justes, Eric; Barriuso, Enrique; Mamy, Laure

2017-02-15

STICS-MACRO is a process-based model simulating the fate of pesticides in the soil-plant system as a function of agricultural practices and pedoclimatic conditions. The objective of this work was to evaluate the influence of crop management practices on water and pesticide flows in contrasted environmental conditions. We used the Morris screening sensitivity analysis method to identify the most influential cropping practices. Crop residues management and tillage practices were shown to have strong effects on water percolation and pesticide leaching. In particular, the amount of organic residues added to soil was found to be the most influential input. The presence of a mulch could increase soil water content so water percolation and pesticide leaching. Conventional tillage was also found to decrease pesticide leaching, compared to no-till, which is consistent with many field observations. The effects of the soil, crop and climate conditions tested in this work were less important than those of cropping practices. STICS-MACRO allows an ex ante evaluation of cropping systems and agricultural practices, and of the related pesticides environmental impacts. Copyright © 2016 Elsevier B.V. All rights reserved.

Emission of pesticides into the air

USGS Publications Warehouse

Van Den, Berg; Kubiak, R.; Benjey, W.G.; Majewski, M.S.; Yates, S.R.; Reeves, G.L.; Smelt, J.H.; Van Der Linden, A. M. A.

1999-01-01

During and after the application of a pesticide in agriculture, a substantial fraction of the dosage may enter the atmosphere and be transported over varying distances downwind of the target. The rate and extent of the emission during application, predominantly as spray particle drift, depends primarily on the application method (equipment and technique), the formulation and environmental conditions, whereas the emission after application depends primarily on the properties of the pesticide, soils, crops and environmental conditions. The fraction of the dosage that misses the target area may be high in some cases and more experimental data on this loss term are needed for various application types and weather conditions. Such data are necessary to test spray drift models, and for further model development and verification as well. Following application, the emission of soil fumigants and soil incorporated pesticides into the air can be measured and computed with reasonable accuracy, but further model development is needed to improve the reliability of the model predictions. For soil surface applied pesticides reliable measurement methods are available, but there is not yet a reliable model. Further model development is required which must be verified by field experiments. Few data are available on pesticide volatilization from plants and more field experiments are also needed to study the fate processes on the plants. Once this information is available, a model needs to be developed to predict the volatilization of pesticides from plants, which, again, should be verified with field measurements. For regional emission estimates, a link between data on the temporal and spatial pesticide use and a geographical information system for crops and soils with their characteristics is needed.

Impact of Spent Mushroom Substrates on the Fate of Pesticides in Soil, and Their Use for Preventing and/or Controlling Soil and Water Contamination: A Review

PubMed Central

Marín-Benito, Jesús M.; Sánchez-Martín, María J.; Rodríguez-Cruz, M. Sonia

2016-01-01

Intensive crop production involves a high consumption of pesticides. This is a cause of major environmental concern because the presence of pesticides in water is becoming increasingly common. Physicochemical methods based on soil modification with organic residues have been developed to enhance the immobilization and/or degradation of pesticides in agricultural soils, which may control both the diffuse and the point pollution of soils and waters. This review summarizes the influence of spent mushroom substrate (SMS) on the environmental fate of pesticides when both are simultaneously applied in agriculture. The processes of adsorption, leaching and dissipation of these compounds in SMS-amended soils were evaluated at laboratory and field scale. Relationships were established between the experimental parameters obtained and the properties of the soils, the SMS, and the pesticides in order to determine the effect that the application of SMS in agricultural soils has on the environmental impact of pesticides. Accordingly, this review highlights the use of SMS as a strategy for the prevention and/or control of soil and water contamination by pesticides to strike a balance between agricultural development and the use of these compounds. PMID:29051422

Occurrence of pesticide non extractable residues in physical and chemical fractions from two natural soils.

NASA Astrophysics Data System (ADS)

Andreou, K.; Jones, K.; Semple, K.

2009-04-01

Distribution of pesticide non extractable residues resulted from the incubation of two natural soils with each of the isoproturon, diazinon and cypermethrin pesticide was assessed in this study. Pesticide non extractable residues distribution in soil physical and chemical fractions is known to ultimately affect their fate. This study aimed to address the fate and behaviour of the non extractable residues in the context of their association with soil physical and chemical fractions with varying properties and characteristics. Non extractable residues were formed from incubation of each pesticide in the two natural soils over a period of 24 months. Soils containing the non extractable residues were fractionated into three solid phase fractions using a physical fractionation procedure as follows: Sediment (SED, >20 μm), (II) Microaggregate (MA, 20-2 μm) and (III) Colloid phase (COL, 2-0.05 μm). Each soil fraction was then fractionated into organic carbon chemical fractionations as follows: Fulvic acid (FA), Humic acid (HA) and Humin (HM). Significant amount of the pesticides was lost during the incubation period. Enrichment factors for the organic carbon and the 14C-pesticide residues were higher in the MA and COL fraction rather than the SED fraction. Greater association and enrichment of the fulvic acid fraction of the organic carbon in the soil was observed. Non extractable residues at the FA fraction showed to diminish while in the HA fraction were increased with decreasing the fraction size. An appreciable amount of non extractable residues were located in the HM fraction but this was less than the amount recovered in the humic substances. Long term fate of pesticide non extractable residues in the soil structural components is important in order to assess any risk associated with them.

Climate-change influences on the response of macroinvertebrate communities to pesticide contamination in the Sacramento River, California watershed.

PubMed

Chiu, Ming-Chih; Hunt, Lisa; Resh, Vincent H

2017-03-01

Limited studies have addressed how future climate-change scenarios may alter the effects of pesticides on biotic assemblages or the effects of exposures to repeated pulses of pesticide mixtures. We used reported pesticide-use data as input to a hydrological fate and transport model (Soil and Water Assessment Tool) under multiple climate-change scenarios to simulate spatiotemporal dynamics of pesticides mixtures in streams on a daily time-step in the Sacramento River watershed of California. We predicted that there will be increased pesticide application with warming across the watershed, especially in upstream areas. Using a statistical model describing the relationship between macroinvertebrate communities and pesticide dynamics, we found that compared to the baseline period of 1970-1999: (1) most climate-change scenarios predicted increased rainfall and warming across the watershed during 2070-2099; and (2) increasing pesticide contamination and increased impact on macroinvertebrates will likely occur in most areas of the watershed by 2070-2099; and (3) lower increases in effects of pesticides on macroinvertebrates were predicted for the downstream areas with intensive agriculture compared to some upstream areas with less-intensive agriculture. Future efforts on practical adaptation and mitigation strategies can be improved by awareness of altered threats of pesticide mixtures under future climate-change conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

Influence of Temperature, Relative Humidity, and Soil Properties on the Soil-Air Partitioning of Semivolatile Pesticides: Laboratory Measurements and Predictive Models.

PubMed

Davie-Martin, Cleo L; Hageman, Kimberly J; Chin, Yu-Ping; Rougé, Valentin; Fujita, Yuki

2015-09-01

Soil-air partition coefficient (Ksoil-air) values are often employed to investigate the fate of organic contaminants in soils; however, these values have not been measured for many compounds of interest, including semivolatile current-use pesticides. Moreover, predictive equations for estimating Ksoil-air values for pesticides (other than the organochlorine pesticides) have not been robustly developed, due to a lack of measured data. In this work, a solid-phase fugacity meter was used to measure the Ksoil-air values of 22 semivolatile current- and historic-use pesticides and their degradation products. Ksoil-air values were determined for two soils (semiarid and volcanic) under a range of environmentally relevant temperature (10-30 °C) and relative humidity (30-100%) conditions, such that 943 Ksoil-air measurements were made. Measured values were used to derive a predictive equation for pesticide Ksoil-air values based on temperature, relative humidity, soil organic carbon content, and pesticide-specific octanol-air partition coefficients. Pesticide volatilization losses from soil, calculated with the newly derived Ksoil-air predictive equation and a previously described pesticide volatilization model, were compared to previous results and showed that the choice of Ksoil-air predictive equation mainly affected the more-volatile pesticides and that the way in which relative humidity was accounted for was the most critical difference.

Modelling of the long-term fate of pesticide residues in agricultural soils and their surface exchange with the atmosphere: Part II. Projected long-term fate of pesticide residues.

PubMed

Scholtz, M T; Bidleman, T F

2007-05-01

In the first part of this paper, a simple coupled dynamic soil-atmosphere model for studying the gaseous exchange of pesticide soil residues with the atmosphere is described and evaluated by comparing model results with published measurements of pesticide concentrations in air and soil. In Part II, the model is used to study the concentration profiles of pesticide residues in both undisturbed and annually tilled agricultural soils. Future trends are estimated for the measured air and soil concentrations of lindane and six highly persistent pesticides (toxaphene, p,p'-DDE, dieldrin, cis- and trans-chlordane and trans-nonachlor) over a twenty-year period due to volatilization and leaching into the deeper soil. Wet deposition and particle associated pesticide deposition (that increase soil residue concentrations) and soil erosion, degradation in the soil (other than for lindane) and run-off in precipitation are not considered in this study. Estimates of the rain deposition fluxes are reported that show that, other than for lindane, net volatilization fluxes greatly exceed rain deposition fluxes. The model shows that the persistent pesticides studied are highly immobile in soil and that loss of these highly persistent residues from the soil is by volatilization rather than leaching into the deeper soil. The soil residue levels of these six pesticides are currently sources of net volatilization to the atmosphere and will remain so for many years. The maximum rate of volatilization from the soil was simulated by setting the atmospheric background concentration to zero; these simulations show that the rates of volatilization will not be significantly increased since soil resistance rather than the atmospheric concentration controls the volatilization rates. Annual tilling of the soils increases the volatilization loss to the atmosphere. Nonetheless, the model predicts that, if only air-soil exchange is considered, more than 76% of current persistent pesticide residues will remain after 20 years in the top 7 cm of annually tilled soils. In contrast, lindane is relatively mobile in soil due to weaker binding to soil carbon and leaching of lindane into soil is the main removal route for current lindane residues near the soil surface. The model predicts that the soil is a sink for lindane in the atmosphere and that soil residue levels of lindane in the surface soil are determined by a balance between dry gaseous deposition to the soil from the atmosphere and leaching from the surface soil into the deeper soil where degradation is the dominant loss route. The model suggests that deposition of lindane from the atmosphere will sustain residues in the soil and, in the absence of fresh applications of lindane to the soil, eliminating lindane from the atmosphere would lead to a rapid decline of lindane residues in agricultural soils of the southern U.S.

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

NASA Astrophysics Data System (ADS)

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.

Fate of pharmaceuticals and pesticides in fly larvae composting.

PubMed

Lalander, C; Senecal, J; Gros Calvo, M; Ahrens, L; Josefsson, S; Wiberg, K; Vinnerås, B

2016-09-15

A novel and efficient organic waste management strategy currently gaining great attention is fly larvae composting. High resource recovery efficiency can be achieved in this closed-looped system, but pharmaceuticals and pesticides in waste could potentially accumulate in every loop of the treatment system and spread to the environment. This study evaluated the fate of three pharmaceuticals (carbamazepine, roxithromycin, trimethoprim) and two pesticides (azoxystrobin, propiconazole) in a fly larvae composting system and in a control treatment with no larvae. It was found that the half-life of all five substances was shorter in the fly larvae compost (<10% of control) and no bioaccumulation was detected in the larvae. Fly larvae composting could thus impede the spread of pharmaceuticals and pesticides into the environment. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Addressing bystander exposure to agricultural pesticides in life cycle impact assessment.

PubMed

Ryberg, Morten Walbech; Rosenbaum, Ralph K; Mosqueron, Luc; Fantke, Peter

2018-04-01

Residents living near agricultural fields may be exposed to pesticides drifting from the fields after application to different field crops. To address this currently missing exposure pathway in life cycle assessment (LCA), we developed a modeling framework for quantifying exposure of bystanders to pesticide spray drift from agricultural fields. Our framework consists of three parts addressing: (1) loss of pesticides from an agricultural field via spray drift; (2) environmental fate of pesticide in air outside of the treated field; and (3) exposure of bystanders to pesticides via inhalation. A comparison with measured data in a case study on pesticides applied to potato fields shows that our model gives good predictions of pesticide air concentrations. We compared our bystander exposure estimates with pathways currently included in LCA, namely aggregated inhalation and ingestion exposure mediated via the environment for the general population, and general population exposure via ingestion of pesticide residues in consumed food crops. The results show that exposure of bystanders is limited relative to total population exposure from ingestion of pesticide residues in crops, but that the exposure magnitude of individual bystanders can be substantially larger than the exposure of populations not living in the proximity to agricultural fields. Our framework for assessing bystander exposure to pesticide applications closes a relevant gap in the exposure assessment included in LCA for agricultural pesticides. This inclusion aids decision-making based on LCA as previously restricted knowledge about exposure of bystanders can now be taken into account. Copyright © 2018 Elsevier Ltd. All rights reserved.

Parameterization models for pesticide exposure via crop consumption.

PubMed

Fantke, Peter; Wieland, Peter; Juraske, Ronnie; Shaddick, Gavin; Itoiz, Eva Sevigné; Friedrich, Rainer; Jolliet, Olivier

2012-12-04

An approach for estimating human exposure to pesticides via consumption of six important food crops is presented that can be used to extend multimedia models applied in health risk and life cycle impact assessment. We first assessed the variation of model output (pesticide residues per kg applied) as a function of model input variables (substance, crop, and environmental properties) including their possible correlations using matrix algebra. We identified five key parameters responsible for between 80% and 93% of the variation in pesticide residues, namely time between substance application and crop harvest, degradation half-lives in crops and on crop surfaces, overall residence times in soil, and substance molecular weight. Partition coefficients also play an important role for fruit trees and tomato (Kow), potato (Koc), and lettuce (Kaw, Kow). Focusing on these parameters, we develop crop-specific models by parametrizing a complex fate and exposure assessment framework. The parametric models thereby reflect the framework's physical and chemical mechanisms and predict pesticide residues in harvest using linear combinations of crop, crop surface, and soil compartments. Parametric model results correspond well with results from the complex framework for 1540 substance-crop combinations with total deviations between a factor 4 (potato) and a factor 66 (lettuce). Predicted residues also correspond well with experimental data previously used to evaluate the complex framework. Pesticide mass in harvest can finally be combined with reduction factors accounting for food processing to estimate human exposure from crop consumption. All parametric models can be easily implemented into existing assessment frameworks.

Environmental Chemistry Methods (ECM) Index - Q

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with Q as the first character.

Environmental Chemistry Methods (ECM) Index - D

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with D as the first character.

Environmental Chemistry Methods (ECM) Index - N

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with N as the first character.

Environmental Chemistry Methods (ECM) Index - P

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with P as the first character.

Environmental Chemistry Methods (ECM) Index - L

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with L as the first character.

Environmental Chemistry Methods (ECM) Index - T

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with T as the first character.

Environmental Chemistry Methods (ECM) Index - A

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with A as the first character.

Environmental Chemistry Methods (ECM) Index - E

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with E as the first character.

Environmental Chemistry Methods (ECM) Index - O

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with O as the first character.

Environmental Chemistry Methods (ECM) Index - Z

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with Z as the first character.

Environmental Chemistry Methods (ECM) Index - I

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with I as the first character.

Environmental Chemistry Methods (ECM) Index - S

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with S as the first character.

Environmental Chemistry Methods (ECM) Index - K

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with K as the first character.

Environmental Chemistry Methods (ECM) Index - R

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with R as the first character.

ECM for Aldicarb in Soil - MRID 49477402

EPA Pesticide Factsheets

laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with A as the first character.

Environmental Chemistry Methods (ECM) Index - G

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with G as the first character.

Environmental Chemistry Methods (ECM) Index - F

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with F as the first character.

Environmental Chemistry Methods (ECM) Index - B

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with B as the first character.

Environmental Chemistry Methods (ECM) Index - M

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with M as the first character.

Environmental Chemistry Methods (ECM) Index - C

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with C as the first character.

Environmental Chemistry Methods (ECM) Index - H

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with H as the first character.

Testing Pearl Model In Three European Sites

NASA Astrophysics Data System (ADS)

Bouraoui, F.; Bidoglio, G.

The Plant Protection Product Directive (91/414/EEC) stresses the need of validated models to calculate predicted environmental concentrations. The use of models has become an unavoidable step before pesticide registration. In this context, European Commission, and in particular DGVI, set up a FOrum for the Co-ordination of pes- ticide fate models and their USe (FOCUS). In a complementary effort, DG research supported the APECOP project, with one of its objective being the validation and im- provement of existing pesticide fate models. The main topic of research presented here is the validation of the PEARL model for different sites in Europe. The PEARL model, actually used in the Dutch pesticide registration procedure, was validated in three well- instrumented sites: Vredepeel (the Netherlands), Brimstone (UK), and Lanna (Swe- den). A step-wise procedure was used for the validation of the PEARL model. First the water transport module was calibrated, and then the solute transport module, using tracer measurements keeping unchanged the water transport parameters. The Vrede- peel site is characterised by a sandy soil. Fourteen months of measurements were used for the calibration. Two pesticides were applied on the site: bentazone and etho- prophos. PEARL predictions were very satisfactory for both soil moisture content, and pesticide concentration in the soil profile. The Brimstone site is characterised by a cracking clay soil. The calibration was conducted on a time series measurement of 7 years. The validation consisted in comparing predictions and measurement of soil moisture at different soil depths, and in comparing the predicted and measured con- centration of isoproturon in the drainage water. The results, even if in good agreement with the measuremens, highlighted the limitation of the model when the preferential flow becomes a dominant process. PEARL did not reproduce well soil moisture pro- file during summer months, and also under-predicted the arrival of isoproturon to the drains. The Lanna site is characterised by s structured clay soil. PEARL was success- ful in predicting soil moisture profiles and the draining water. PEARL performed well in predicting the soil concentration of bentazone at different depth. However, since PEARL does not consider cracks in the soil, it did not predict well the peak concen- trations of bentazone in the drainage water. Along with the validation results for the three sites, a sensitivity analysis of the model is presented.

EVALUATION OF A PROTOCOL FOR DRINKING WATER TREATMENT DATA REQUIRED BY THE FOOD QUALITY PROTECTION ACT

EPA Science Inventory

Under the Food Quality Protection Act (FQPA), the USEPA Office of Pesticide Programs (OPP) considers drinking water as a route for pesticide exposure in its human health risk assessments, and may require data on the fate of a pesticide in drinking water be supplied to OPP by the ...

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

USGS Publications Warehouse

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

2008-01-01

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

Environmental Chemistry Methods (ECM) Index - 0-9

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with a number as the first character.

ECM for Aldicarb & Degradates in Water - MRID 49515901

EPA Pesticide Factsheets

aboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with A as the first character.

Modeling of pesticide emissions from agricultural ecosystems

NASA Astrophysics Data System (ADS)

Li, Rong

2012-04-01

Pesticides are applied to crops and soils to improve agricultural yields, but the use of pesticides has become highly regulated because of concerns about their adverse effects on human health and environment. Estimating pesticide emission rates from soils and crops is a key component for risk assessment for pesticide registration, identification of pesticide sources to the contamination of sensitive ecosystems, and appreciation of transport and fate of pesticides in the environment. Pesticide emission rates involve processes occurring in the soil, in the atmosphere, and on vegetation surfaces and are highly dependent on soil texture, agricultural practices, and meteorology, which vary significantly with location and/or time. To take all these factors into account for simulating pesticide emissions from large agricultural ecosystems, this study coupled a comprehensive meteorological model with a dynamic pesticide emission model. The combined model calculates hourly emission rates from both emission sources: current applications and soil residues resulting from historical use. The coupled modeling system is used to compute a gridded (36 × 36 km) hourly toxaphene emission inventory for North America for the year 2000 using a published U.S. toxaphene residue inventory and a Mexican toxaphene residue inventory developed using its historical application rates and a cropland inventory. To my knowledge, this is the first such hourly toxaphene emission inventory for North America. Results show that modeled emission rates have strong diurnal and seasonal variations at a given location and over the entire domain. The simulated total toxaphene emission from contaminated agricultural soils in North America in 2000 was about 255 t, which compares reasonably well to a published annual estimate. Most emissions occur in spring and summer, with domain-wide emission rates in April, May and, June of 36, 51, and 35 t/month, respectively. The spatial distribution of emissions depends on the distribution of toxaphene soil residues, and high emission rates coincide with heavily contaminated areas.

Evaluated fate and effects of atrazine and lambda-cyhalothrin in vegetated and unvegetated microcosms.

PubMed

Bouldin, J L; Farris, J L; Moore, M T; Smith, S; Stephens, W W; Cooper, C M

2005-10-01

Contaminants such as nutrients, metals, and pesticides can interact with constructed wetlands and existing drainage ditches used as agricultural best-management practices. Our research has shown that the presence of macrophytes and a hydrologic regime aid in the transfer and transformation of pesticides associated with agricultural runoff. This study consisted of application of both atrazine (triazine herbicide) and lambda-cyhalothrin (pyrethroid insecticide) to vegetated and unvegetated microcosms in order to measure the fate and effects of pesticides applied at suggested field application rates. Exposures focused on monocultures of Ludwigia peploides (water primrose) and Juncus effusus (soft rush). Pesticide sorption was evident through concentrations of atrazine and lambda-cyhalothrin in plant tissue as high as 2461.4 and 86.50 microg/kg, respectively. Toxicity was measured in water from unvegetated microcosms for 28 days and in Chironomus tentans (midge larvae) exposed to sediment collected from 3 h to 56 days in microcosms receiving the pesticide combination. The comparative survival of test organisms in this study suggests that effective mitigation of pesticides from runoff can depend on the macrophyte contact and vegetative attributes associated with ditches. (c) 2005 Wiley Periodicals, Inc.

Environmental risk assessment of pesticides: state of the art and prospective improvement from science.

PubMed

Boivin, Arnaud; Poulsen, Véronique

2017-03-01

Pesticide risk assessment in the European regulatory framework is mandatory performed for active substances (pesticides) and the plant protection products they are constituents of. The aim is to guarantee that safe use can be achieved for the intended use of the product. This paper provides a feedback on the regulatory environmental risk assessment performed for pesticide registration at the EU and member state levels. The different steps of pesticide registration are addressed considering both exposure and hazard. In this paper, we focus on the environmental fate and behaviour in surface water together with the aquatic ecotoxicity of the substances to illustrate pesticide regulatory risk assessment performed for aquatic organisms. Current methodologies are presented along with highlights on potential improvements. For instance, as regards exposure aspects, moving from field based to landscape risk assessments is promising. Regarding ecotoxicology, ecological models may be valuable tools when applied to chemical risk assessment. In addition, interest and further developments to better take into account mitigation measures in risk assessment and management are also presented.

Sorption of triazine and organophosphorus pesticides on soil and biochar

USDA-ARS?s Scientific Manuscript database

Although a large number of reports are available on sorption and degradation of triazine and organophosphorus pesticides in soils, systematic studies are lacking to directly compare and predict the fate of agrochemicals having different susceptibilities for hydrolysis and other degradation pathways....

Simulation of the fate of Boscalid and its transformation product 4-Chlorobenzoic acid in a vineyard-terraces catchment

NASA Astrophysics Data System (ADS)

Vollert, Dieter; Gassmann, Matthias; Olsson, Oliver; Kümmerer, Klaus

2017-04-01

In the viniculture fungicides are commonly applied foliar on the plant surface, resulting in high concentrations in runoff water. The fungicide Boscalid occurred frequently and in high concentrations in runoff water in the Loechernbach catchment, a 180 ha vineyard catchment in south-west Germany, during rainfall-runoff events in 2016. The catchment is characterized by a typical terraces structure and the connection of a dense road network. The washing off from drift-depositions on the streets is expected to be a major pathway for pesticides. The main objective of this study was the provision of a catchment model to simulate the transport and transformation processes of Boscalid. Based on this model, source areas of Boscalid residue pollution and its export pathways will be identified and provide urgently needed information for the development of water pollution control strategies. The distributed, process-based, reactive transport catchment model ZIN-AgriTra was used for the evaluation of the pesticide mobilization and the export processes. The hydrological model was successfully calibrated for a 6-month high-resolution time series of discharge data. Pesticide modelling was calibrated for single rainfall events after Boscalid application. Additionally, the transformation product 4-Chlorobenzoic acid has been simulated using literature substance parameters, in order to gain information about anticipated environmental concentrations. The pathways for the discharge of Boscalid were characterized and the streets were confirmed as major pathway for the pesticide discharge in the catchment. The main Boscalid loss occured during the first flush after a storm event containing concentrations up to 10 µg/l. The results show that storage on surfaces without sorption contributes significantly to the export of pesticides through the first flush. Therefore, the mobilization process affects a combination of both sorptive (e.g. at the soil) and non-sorptive (e.g. on the surface) storages at the roads. Furthermore, measurements and simulation results show that there are background pesticide concentrations, an order of magnitude lower than the first flush concentration, for the whole simulation period. Additionally, almost half of the applied Boscalid still remains as residue in the soil at the end of the simulated 6-month period, because of slow degradation rates of Boscalid. The transformation product 4-Chlorobenzoic acid was simulated to have concentrations in the range of 0.1 µg/l. The model assumes that subsurface flow is the major loss pathway for this substance. Concluding, the introduced catchment model is an applicable tool to simulate the individual processes of the Boscalid fate in the vineyard catchment. It was confirmed that roads receiving pesticide drift are the major loss areas of Boscalid in the Loechernbach catchment.

Meta-modeling of the pesticide fate model MACRO for groundwater exposure assessments using artificial neural networks

NASA Astrophysics Data System (ADS)

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 mapped for a small field. It was shown that the area of the field that contributes most to leaching depends on the properties of the compound in question. It is concluded that the simulation meta-model of MACRO should prove useful for mapping relative pesticide leaching risks at large scales.

A client-server software for the identification of groundwater vulnerability to pesticides at regional level.

PubMed

Di Guardo, Andrea; Finizio, Antonio

2015-10-15

The groundwater VULnerability to PESticide software system (VULPES) is a user-friendly, GIS-based and client-server software developed to identify vulnerable areas to pesticides at regional level making use of pesticide fate models. It is a Decision Support System aimed to assist the public policy makers to investigate areas sensitive to specific substances and to propose limitations of use or mitigation measures. VULPES identify the so-called Uniform Geographical Unit (UGU) which are areas characterised by the same agro-environmental conditions. In each UGU it applies the PELMO model obtaining the 80th percentile of the substance concentration at 1 metre depth; then VULPES creates a vulnerability map in shapefile format which classifies the outputs comparing them with the lower threshold set to the legal limit concentration in groundwater (0.1 μg/l). This paper describes the software structure in details and a case study with the application of the terbuthylazine herbicide on the Lombardy region territory. Three zones with different degrees of vulnerabilities has been identified and described. Copyright © 2015 Elsevier B.V. All rights reserved.

Microbial degradation on glacier surface is the missing piece of environmental fate of pesticides in cold areas

NASA Astrophysics Data System (ADS)

Ambrosini, Roberto; Ferrario, Claudia; Pittino, Francesca; Tagliaferri, Ilario; Gandolfi, Isabella; Bestetti, Giuseppina; Azzoni, Roberto S.; Diolaiuti, Guglielmina A.; Smiraglia, Claudio; Franzetti, Andrea; Villa, Sara

2017-04-01

Organic contaminants deposited on glacier surfaces undergo different partition and degradation processes which determine their environmental fate and accumulation into the trophic chains. Among these processes, biodegradation by supraglacial bacteria has been neglected so far. To assess the relevance of biodegradative processes, in situ microcosm experiments were conducted simulating cryoconite hole systems on an Alpine glacier exposed to the organophosphorus insecticide chlorpyrifos (CPF) as model of xenobiotic molecule which accumulate on glaciers after medium range transports. Results showed that biodegradation is the most efficient process contributing to the removal of CPF on the glacier surface. The high concentrations of CPF in cryoconite and its half-life in the range of 35 - 69 days indicated that biodegradation process can significantly contrast the release of CPF transported on glaciers. Moreover, the metabolic versatility of cryoconite bacteria suggest that these habitats might contribute to the degradation of a wide class of pollutants with different physical-chemical properties. Metagenomics data indicated that photoheterotrophic bacteria might be involved in the biodegradation of CPF by using light to supplement their metabolic demands, thus contributing to the biological removal of CPF without the constrain of using this pesticide as sole energy source. In conclusion. cryoconite might act as a "biofilter" for organic pollutants on glaciers by accumulating them and promoting their biodegradation. Owing to its relevance, the contribution of cryoconite to the removal of organic pollutants should be included in the models predicting the environmental fate of these compounds in cold areas.

Non-hazardous pesticide concentrations in surface waters: An integrated approach simulating application thresholds and resulting farm income effects.

PubMed

Bannwarth, M A; Grovermann, C; Schreinemachers, P; Ingwersen, J; Lamers, M; Berger, T; Streck, T

2016-01-01

Pesticide application rates are high and increasing in upland agricultural systems in Thailand producing vegetables, fruits and ornamental crops, leading to the pollution of stream water with pesticide residues. The objective of this study was to determine the maximum per hectare application rates of two widely used pesticides that would achieve non-hazardous pesticide concentrations in the stream water and to evaluate how farm household incomes would be affected if farmers complied with these restricted application rates. For this purpose we perform an integrated modeling approach of a hydrological solute transport model (the Soil and Water Assessment Tool, SWAT) and an agent-based farm decision model (Mathematical Programming-based Multi-Agent Systems, MPMAS). SWAT was used to simulate the pesticide fate and behavior. The model was calibrated to a 77 km(2) watershed in northern Thailand. The results show that to stay under a pre-defined eco-toxicological threshold, the current average application of chlorothalonil (0.80 kg/ha) and cypermethrin (0.53 kg/ha) would have to be reduced by 80% and 99%, respectively. The income effect of such reductions was simulated using MPMAS. The results suggest that if farm households complied with the application thresholds then their income would reduce by 17.3% in the case of chlorothalonil and by 38.3% in the case of cypermethrin. Less drastic income effects can be expected if methods of integrated pest management were more widely available. The novelty of this study is to combine two models from distinctive disciplines to evaluate pesticide reduction scenarios based on real-world data from a single study site. Copyright © 2014 Elsevier Ltd. All rights reserved.

Modeling the Factors Impacting Pesticide Concentrations in Groundwater Wells.

PubMed

Aisopou, Angeliki; Binning, Philip J; Albrechtsen, Hans-Jørgen; Bjerg, Poul L

2015-01-01

This study examines the effect of pumping, hydrogeology, and pesticide characteristics on pesticide concentrations in production wells using a reactive transport model in two conceptual hydrogeologic systems; a layered aquifer with and without a stream present. The pumping rate can significantly affect the pesticide breakthrough time and maximum concentration at the well. The effect of the pumping rate on the pesticide concentration depends on the hydrogeology of the aquifer; in a layered aquifer, a high pumping rate resulted in a considerably different breakthrough than a low pumping rate, while in an aquifer with a stream the effect of the pumping rate was insignificant. Pesticide application history and properties have also a great impact on the effect of the pumping rate on the concentration at the well. The findings of the study show that variable pumping rates can generate temporal variability in the concentration at the well, which helps understanding the results of groundwater monitoring programs. The results are used to provide guidance on the design of pumping and regulatory changes for the long-term supply of safe groundwater. The fate of selected pesticides is examined, for example, if the application of bentazone in a region with a layered aquifer stops today, the concentration at the well can continue to increase for 20 years if a low pumping rate is applied. This study concludes that because of the rapid response of the pesticide concentration at the drinking water well due to changes in pumping, wellhead management is important for managing pesticide concentrations. © 2014, National GroundWater Association.

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

NASA Astrophysics Data System (ADS)

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 and CSIA data and advocates the use of travel-time distributions for assessing pesticide fate and transport on catchment scale.

Biochar soil additions impacts herbicide fate: Importance of application timing and feedstock species

USDA-ARS?s Scientific Manuscript database

BACKGROUND: Biochar (BC), solid biomass subjected to pyrolysis, can alter the fate of pesticides in soil. We investigated the effect of soil amendment with several biochars on the sorption, persistence, leaching and bioefficacy of the herbicides clomazone (CMZ) and bispyribac sodium (BYP). RESULTS:...

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

Code of Federal Regulations, 2011 CFR

2011-07-01

... describe how to use this table to determine the terrestrial and aquatic nontarget organisms data... this section. (b) Use patterns. Aquatic uses include: food and feed, nonfood uses (e.g., outdoor... Organisms and Environmental Fate Data Requirements Guideline Number Data Requirement Use Patterns Aquatic...

Transformation of Organophosphorus Pesticides in the Presence of Aqueous Chlorine: Kinetics, Pathways, and Structure-Activity Relationships

EPA Science Inventory

The fate of organophosphorus (OP) pesticides in the presence of aqueous chlorine was investigated under simulated drinking water treatment conditions. Intrinsic rate coefficients were found for the reaction of hypochlorous acid (kHOCl,OP) and hypochlorite ion (kOCl,OP) for eight...

PERSISTENCE IN SOIL OF TRANSGENIC PLANT PRODUCED BACILLUS THURINGIENSIS VAR. KURSTAKI O-ENDOTOXIN1

EPA Science Inventory

Transgenic plants that produce pesticidal proteins will release these proteins into the soil when these plants are incorporated into the soil by tillage or as leaf litter. Little is known about the fate and persistence of transgenic plant pesticidal products in the soil. We used ...

Biogeochemical Factors Influencing the Transport and Fate of Colloids and Colloid-Associated Contaminants in the Vadose Zone

NASA Astrophysics Data System (ADS)

Bradford, S. A.

2016-12-01

The vadose zone exhibits large spatial and temporal variability in many physical, chemical, and biological factors that strongly influence the transport and fate of colloids (e.g., microbes, nanoparticles, clays, and dissolved organic matter) and colloid-associated contaminants (e.g., heavy metals, radionuclides, pesticides, and antibiotics). This presentation highlights our research activities to better understand and predict the influence of specific biogeochemical processes on colloid and colloid-facilitated transport. Results demonstrate the sensitivity of colloid transport, retention, release, and clogging to transients in solution chemistry (e.g., ionic strength, pH, cation and anion type, and surfactants), water velocity and saturation, and preferential flow. Mathematical modeling at interface-, pore-, and continuum-scales is shown to be a critical tool to quantify the relative importance and coupling of these biogeochemical factors on colloid and contaminant transport and fate, which otherwise might be experimentally intractable. Existing gaps in knowledge and model limitations are identified.

A globally applicable location-specific screening model for assessing the relative risk of pesticide leaching.

PubMed

Whelan, M J; Davenport, E J; Smith, B G

2007-05-15

A screening model of pesticide leaching loss is described which forms part of a multi-criteria risk-based indicator system called PRoMPT (Pesticide Risk Management and Profiling Tool). The leaching model evaluates pesticide fate in soil for any application rate and time of application (including multiple applications), for any land-based location in the world. It considers a generic evaluative environment with fixed dimensions and soil properties. The soil profile is conceptualised as a number of discrete layers. Equilibrium partitioning between adsorbed and dissolved chemical (based on the organic carbon-water partition coefficient [K(OC)]) is assumed in each time step, in each layer. Non-leaching losses are described using first order kinetics. Drainage is assumed to be uniform throughout the soil profile but varies temporally. The drainage rate, which can be augmented by evapotranspiration-adjusted irrigation, is derived from long-term mean monthly water balance model calculations performed for 30 arc-minute grid cells across the entire ice-free land surface of the earth. Although, such predictions are approximate, they do capture the seasonality and relative magnitude of drainage and allow the model to be applied anywhere, without the need for extensive data compilation. PRoMPT predictions are shown to be consistent with those made by more sophisticated models (PRZM, PELMO and PEARL) for the FOCUS groundwater scenarios.

Pesticide fate and transport throughout unsaturated zones in five agricultural settings, USA

USGS Publications Warehouse

Hancock, T.C.; Sandstrom, M.W.; Vogel, J.R.; Webb, R.M.T.; Bayless, E.R.; Barbash, J.E.

2008-01-01

Pesticide transport through the unsaturated zone is a function of chemical and soil characteristics, application, and water recharge rate. The fate and transport of 82 pesticides and degradates were investigated at five different agricultural sites. Atrazine and metolachlor, as well as several of the degradates of atrazine, metolachlor, acetochlor, and alachlor, were frequently detected in soil water during the 2004 growing season, and degradates were generally more abundant than parent compounds. Metolachlor and atrazine were applied at a Nebraska site the same year as sampling, and focused recharge coupled with the short time since application resulted in their movement in the unsaturated zone 9 m below the surface. At other sites where the herbicides were applied 1 to 2 yr before sampling, only degradates were found in soil water. Transformations of herbicides were evident with depth and during the 4-mo sampling time and reflected the faster degradation of metolachlor oxanilic acid and persistence of metolachor ethanesulfonic acid. The fraction of metolachlor ethanesulfonic acid relative to metolachlor and metolachlor oxanilic acid increased from 0.3 to > 0.9 at a site in Maryland where the unsaturated zone was 5 m deep and from 0.3 to 0.5 at the shallowest depth. The flux of pesticide degradates from the deepest sites to the shallow ground water was greatest (3.0–4.9 μmol m−2 yr−1) where upland recharge or focused flow moved the most water through the unsaturated zone. Flux estimates based on estimated recharge rates and measured concentrations were in agreement with fluxes estimated using an unsaturated-zone computer model (LEACHM).

Modelling the dissipation and leaching of two herbicides in decomposing mulch of crop residues

NASA Astrophysics Data System (ADS)

Aslam, Sohaib; Iqbal, Akhtar; Lafolie, François; Recous, Sylvie; Benoit, Pierre; Garnier, Patricia

2013-04-01

Conservation agricultural practices are increasingly adopted because of ecosystem services such as conservation of soil and water resources. These farming systems are characterized mainly by the presence of mulch made of residues of harvested or cover crops on soil surface. The mulch can intercept and retain applied pesticides depending on pesticide molecule and rainfall timing. The pesticide wash-off from mulch is considered a key process in pesticide fate and can have effects on degradation and transport processes. This work highlights a modelling approach to study the pesticide wash-off from mulch residues and their further transport in soil under two rainfall regimes. Transformation and leaching of two herbicides, s-metolachlor and glyphosate, was studied and simulated by Pastis-mulch model. A pesticide module describing pesticide degradation in mulch and soil was coupled to a transport model including a mulch module. The model was tested to simulate the pesticide dissipation, wash-off from mulch and further leaching in soil. Pesticide degradation parameters in mulch were estimated from incubation experiments with 14C-labelled molecules in small cylinders. The model was then tested using the data obtained through a soil column experiment (reconstructed soil cores :15 cm diameter x 35 cm depth), a mulch of Zea mais + Doliquos lablab and with two treatments varied by water regimes: i) frequent rain (temperate, twice a week) with week intensity (6 mm/hr); and ii) occasional rain (tropical, twice a month) with stronger intensity (20 mm/hr). Columns were incubated at 20 °C for 84 days to monitor soil water, C, N and pesticide dynamics. Model successfully simulated the experimental data of pesticide dissipation in mulch residues. Results showed that the rain regime affected more S-metolachlor than glyphosate behavior. The simulated results indicated also that the dynamics in mulch of the two molecules differed according to the rain treatment. Glyphosate showed a greater leaching from mulch than S-metolachlor because of its lower adsorption coefficients to organic mulch. Moreover, simulated results showed a much faster degradation of glyphosate but greater non-extractable residue formation for S-metolachlor. Keywords: Mulch; Pesticides; Transport; Degradation; Modeling; Pastis-mulch References Findeling, A., Garnier, P., Coppens, F., Lafolie, F., Recous, S., 2007. Modelling water, carbon and nitrogen dynamics in soil covered with decomposing mulch. European Journal of Soil Science 58, 196-206. Lashermes, G., Zhang, Y., Houot, S., Barriuso, E., Steyer, J.P., Patureau, D., Garnier, P., 2013. A model coupling organic carbon and organic pollutant dynamics during composting. Journal of Environmental Quality. In Press.

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

Code of Federal Regulations, 2010 CFR

2010-07-01

... Freshwater invertebrate toxicity/pathogenicity NR R R R NR NR NR NR TGAI 1, 2, 3 885.4300 Nontarget... exposure. Freshwater invertebrates are preferred for invertebrate testing. 3. Required when there will be significant exposure to aquatic organisms (fish and invertebrates). 4. Required if the microbial pesticide is...

Pesticide fate and transport from farm fields adjacent to the Jobos Bay National Estuarine Research Reserve

USDA-ARS?s Scientific Manuscript database

Agriculture is a primary land-use in the Jobos Bay National Estuarine Research Reserve (JBNERR) watershed located on Puerto Rico's southeast coast. Crop production in near-shore areas depends on pesticides for weed, disease and insect control. There are continuing concerns about their potential fo...

Designing herbicide formulation characteristics to maximize efficacy and minimize rice injury in paddy environments.

PubMed

Cryer, S A; Mann, R K; Erhardt-Zabik, S; Keeney, F N; Handy, P R

2001-06-01

Mathematical descriptors, coupled with experimental observations, are used to quantify differential uptake of an experimental herbicide in Japonica and Indica rice (Oryza sativa, non-target) and barnyardgrass (Echinochloa crus-galli, target). Partitioning, degradation, plant uptake and metabolism are described using mass-balance conservation equations in the form of kinetic approximations. Estimated environmental concentrations, governed by the pesticide formulation, are described using superimposed analytical solutions for the one-dimensional diffusion equation in spherical coordinates and by a finite difference representation of the two-dimensional diffusion equation in Cartesian coordinates. Formulation attributes from granules include active ingredient release rates, particle sizes, pesticide loading, and granule spacing. The diffusion model for pesticide transport is coupled with the compartment model to follow the fate and transport of a pesticide from its initial application location to various environmental matrices of interest. Formulation effects, partitioning and degradation in the various environmental matrices, differential plant uptake and metabolism, and dose-response information for plants are accounted for. This novel model provides a mechanism for selecting formulation delivery systems that optimize specific attributes (such as weed control or the therapeutic index) for risk-assessment procedures. In this report we describe how this methodology was used to explore the factors affecting herbicide efficacy and to define an optimal release rate for a granule formulation.

A moni-modelling approach to manage groundwater risk to pesticide leaching at regional scale.

PubMed

Di Guardo, Andrea; Finizio, Antonio

2016-03-01

Historically, the approach used to manage risk of chemical contamination of water bodies is based on the use of monitoring programmes, which provide a snapshot of the presence/absence of chemicals in water bodies. Monitoring is required in the current EU regulations, such as the Water Framework Directive (WFD), as a tool to record temporal variation in the chemical status of water bodies. More recently, a number of models have been developed and used to forecast chemical contamination of water bodies. These models combine information of chemical properties, their use, and environmental scenarios. Both approaches are useful for risk assessors in decision processes. However, in our opinion, both show flaws and strengths when taken alone. This paper proposes an integrated approach (moni-modelling approach) where monitoring data and modelling simulations work together in order to provide a common decision framework for the risk assessor. This approach would be very useful, particularly for the risk management of pesticides at a territorial level. It fulfils the requirement of the recent Sustainable Use of Pesticides Directive. In fact, the moni-modelling approach could be used to identify sensible areas where implement mitigation measures or limitation of use of pesticides, but even to effectively re-design future monitoring networks or to better calibrate the pedo-climatic input data for the environmental fate models. A case study is presented, where the moni-modelling approach is applied in Lombardy region (North of Italy) to identify groundwater vulnerable areas to pesticides. The approach has been applied to six active substances with different leaching behaviour, in order to highlight the advantages in using the proposed methodology. Copyright © 2015 Elsevier B.V. All rights reserved.

76 FR 35383 - Pesticides; Policies Concerning Products Containing Nanoscale Materials; Opportunity for Public...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-17

... information on a product's composition, and its fate in the environment and within the human body. For certain... present in a registered pesticide product and its potential effects on humans or the environment. If EPA... in the body of your comment. If you send an e- mail comment directly to EPA without going through...

ATMOSPHERIC DEPOSITION OF CURRENT-USE AND HISTORIC-USE PESTICIDES IN SNOW AT NATIONAL PARKS IN THE WESTERN UNITED STATES

EPA Science Inventory

The United States (U.S.) National Park Service has initiated research on the atmospheric deposition and fate of semi-volatile organic compounds in its alpine, sub-Arctic, and Arctic ecosystems in the Western U.S. Results for the analysis of pesticides in seasonal snowpack samples...

CFD simulation of pesticide spray from air-assisted sprayers in an apple orchard: tree deposition and off-target losses

USDA-ARS?s Scientific Manuscript database

The ultimate goal of a pesticide spraying system is to provide adequate coverage on intended canopies with a minimum amount of spray materials and off-target waste. Better spray coverage requires an understanding of the fate and transport of spray droplets carried by turbulent airflows in orchards. ...

Modelling of Pesticide Transport During An Injection Experiment In A Physical and Geochemical Heterogeneous Aquifer

NASA Astrophysics Data System (ADS)

Hojberg, A. L.; Engesgaard, P.; Bjerg, P. L.

The fate of selected pesticides under natural groundwater conditions was studied by natural gradient short and long term injection experiments in a shallow uncon- fined aerobic aquifer. Bentazone, DNOC, MCPP, dichlorprop, isoproturon, and BAM (dichlobenil metabolite) were injected in aqueous solution with bromide as a nonre- active tracer. The Bromide and pesticide plumes were sampled during the initial 25 m of migration in a dense monitoring net of multilevel samplers. The aquifer was physical and geochemical heterogeneous, which affected transport of several of the pesticides. A 3D reactive transport code was developed including one- and two-site linear/nonlinear equilibrium/nonequilibrium sorption and first-order as well as single Monod degradation kinetic coupled to microbial growth. Model simulations demon- strated that microbial growth was likely supported by the phenoxy acids MCPP and dichlorprop, while degradation of DNOC was adequately described by first-order degradation with no initial lag time. An observed vertical increase in pH was observed at the site and implemented in the transport code. The numerical analysis indicated that degradation of the three degradable pesticides may have been affected by vertical pH variations. Spatial variability in observed DNOC sorption was similarly suspected to be an effect of varying pH. pH dependency on DNOC sorption was confirmed by the model recognized by a match to observed breakthrough at the individual sampling points, when pH variation was included in the simulations.

CFD simulation of pesticide spray from air-assisted sprayers in an apple orchard: Tree deposition and off-target losses

NASA Astrophysics Data System (ADS)

Hong, Se-Woon; Zhao, Lingying; Zhu, Heping

2018-02-01

The ultimate goal of a pesticide spraying system is to provide adequate coverage on intended canopies with a minimum amount of spray materials and off-target waste. Better spray coverage requires an understanding of the fate and transport of spray droplets carried by turbulent airflows in orchards. In this study, an integrated computational fluid dynamics (CFD) model was developed to predict displacement of pesticide spray droplets discharged from an air-assisted sprayer, depositions onto tree canopies, and off-target deposition and airborne drift in an apple orchard. Pesticide droplets discharged from a moving sprayer were tracked using the Lagrangian particle transport model, and the deposition model was applied to droplets entering porous canopy zones. Measurements of the droplet deposition and drift in the same orchard were used to validate the model simulations. Good agreement was found between the measured and simulated spray concentrations inside tree canopies and off-target losses (ground deposition and airborne drifts) with the overall relative errors of 22.1% and 40.6%, respectively, under three growth stages. The CFD model was able to estimate the mass balance of pesticide droplets in the orchard, which was practically difficult to investigate by measurements in field conditions. As the foliage of trees became denser, spray deposition inside canopies increased from 8.5% to 65.8% and airborne drift and ground deposition decreased from 25.8% to 7.0% and 47.8% to 21.2%, respectively. Higher wind speed also increased the spray airborne drift downwind of the orchard. This study demonstrates that CFD model can be used to evaluate spray application performance and design and operate sprayers with increased spray efficiencies and reduced drift potentials.

Analytical solution describing pesticide volatilization from soil affected by a change in surface condition.

PubMed

Yates, S R

2009-01-01

An analytical solution describing the fate and transport of pesticides applied to soils has been developed. Two pesticide application methods can be simulated: point-source applications, such as idealized shank or a hot-gas injection method, and a more realistic shank-source application method that includes a vertical pesticide distribution in the soil domain due to a soil fracture caused by a shank. The solutions allow determination of the volatilization rate and other information that could be important for understanding fumigant movement and in the development of regulatory permitting conditions. The solutions can be used to characterize differences in emissions relative to changes in the soil degradation rate, surface barrier conditions, application depth, and soil packing. In some cases, simple algebraic expressions are provided that can be used to obtain the total emissions and total soil degradation. The solutions provide a consistent methodology for determining the total emissions and can be used with other information, such as field and laboratory experimental data, to support the development of fumigant regulations. The uses of the models are illustrated by several examples.

Chiral pesticides: identification, description, and environmental implications.

PubMed

Ulrich, Elin M; Morrison, Candice N; Goldsmith, Michael R; Foreman, William T

2012-01-01

Of the 1,693 pesticides considered in this review, 1,594 are organic chemicals, 47 are inorganic chemicals, 53 are of biological origin (largely non chemical; insect,fungus, bacteria, virus, etc.), and 2 have an undetermined structure. Considering that the EPA's Office of Pesticide Programs found 1,252 pesticide active ingredients(EPA Pesticides Customer Service 2011), we consider this dataset to be comprehensive; however, no direct comparison of the compound lists was undertaken. Of all pesticides reviewed, 482 (28%) are chiral; 30% are chiral when considering only the organic chemical pesticides. A graph of this distribution is shown in Fig. 7a. Each pesticide is classified with up to three pesticidal utilities (e.g., fungicide, plant growth regulator, rodenticide, etc.), taken first from the Pesticide Manual as a primary source, and the Compendium of Common Pesticide Names website as a secondary source. Of the chiral pesticides, 195 (34%) are insecticides (including attractants, pheromones, and repellents), 150 (27%) are herbicides (including plant growth regulators and herbicide safeners), 104 (18%) are fungicides, and 55 (10%)are acaricides. The distribution of chiral pesticides by utility is shown in Fig. 7b,including categories of pesticides that make up 3%t or less of the usage categories.Figure 7c shows a similar distribution of non chiral pesticide usage categories. Of the chiral pesticides, 270 (56%) have one chiral feature, 105 (22%) have two chiral features, 30 (6.2%) have three chiral features, and 29 (6.0%) have ten or more chiral features.Chiral chemicals pose many difficulties in stereospecific synthesis, characterization, and analysis. When these compounds are purposely put into the environment,even more interesting complications arise in tracking, monitoring, and predicting their fate and risks. More than 475 pesticides are chiral, as are other chiral contaminants such as pharmaceuticals, polychlorinated biphenyls, brominated flame retardants, synthetic musks, and their degradates (Kallenborn and Hiihnerfuss 2001;Heeb et al. 2007; Hihnerfuss and Shah 2009). The stereoisomers of pesticides can have widely different efficacy, toxicity to nontarget organisms, and metabolic rates in biota. For these reasons, it is important to first be aware of likely fate and effect differences, to incorporate molecular asymmetry insights into research projects, and to study the individual stereoisomers of the applied pesticide material.With the advent of enantioselective chromatography techniques, the chirality of pesticides has been increasingly studied. While the ChirBase (Advanced ChemistryDevelopment 1997-2010) database does not include all published chiral analytical separations, it does contain more than 3,500 records for 146 of the 482 chiral pesticides (30%). The majority of the records are found in the liquid chromatography database (2,677 or 76%), followed by the gas chromatography database (652 or 18%),and the capillary electrophoresis database (203 or 6%). The finding that only 30% of the chiral pesticides covered in this review have entries in ChirBase highlights the need for expanded efforts to develop additional enantioselective chromatographic methods. Other techniques (e.g., nuclear magnetic resonance and other spectroscopy)are available for investigation of chiral compounds, but often are not utilized because of cost, complexity, or simply not recognizing that a pesticide is chiral.In this review, we have listed and have briefly described the general nature of chiral fungicides, herbicides, insecticides, and other miscellaneous classes. A data-set generated for this review contains 1,693 pesticides, the number of enantioselective separation records in ChirBase, pesticide usage class, SMILES structure string and counts of stereogenic centers. This dataset is publically available for download at the following website: http://www.epa.gov/heasd/products/products.html. With the information herein coupled to the publically accessible dataset, we can begin to develop the tools to handle molecular asymmetry as it applies to agrochemicals.Additional structure-based resources would allow further analysis of key parameters (e.g., exposure, toxicity, environmental fate, degradation, and risks) for individual stereoisomers of chiral compounds.

Risk assessment for pesticide contamination of groundwater with sparse available data

NASA Astrophysics Data System (ADS)

Bardowicks, K.; Heredia, O.; Billib, M.; Fernández Cirelli, A.; Boochs, P.

2009-04-01

The contamination of the water resources by agrochemicals is recognized in industrial countries as a very important environmental problem, nevertheless in most of developing and threshold countries the risks for health and environmental problems are not considered. In these countries agrochemicals, which are forbidden since several years in Europe (e.g. atrazine), are still in use. In some threshold countries monitoring systems are already installed for nutrients (N, P) and also a few for heavy metals, but so far the contamination by pesticides is hardly ever controlled, thus there is no data available about pesticide concentrations in soil and water. The aim of this research is to develop a methodology to show farmers and other water users (water agencies, drinking water supply companies) in basins of developing or threshold countries with sparse available data the risk of contamination of the groundwater resources by pesticides. A few data like pesticide application, precipitation, irrigation, potential evaporation and soil types are available in some regions. If these data is reliable it can be used together with some justified estimated parameters to perform simulations of the fate of pesticides to the groundwater. Therefore in two study cases in Argentina and Chile pesticide models (e.g. PESTAN, IPTM-CS) were used to evaluate the risk of contamination of the groundwater. The results were compared with contamination indicators, like one developed by O. Heredia, for checking their plausibility. Afterwards the results of the models were used as input data for simulations at the catchment scale, for instance for a groundwater simulation model (VISUAL MODFLOW). The results show a great risk for the contamination of the groundwater resources in the selected study areas, especially by atrazine. On this account the findings will be used by local researchers to improve the knowledge and the awareness of farmers and other stakeholders about the contamination of the water resources by pesticides.

The influence of particles on bioavailability and toxicity of pesticides in surface water.

PubMed

Knauer, Katja; Homazava, Nadzeya; Junghans, Marion; Werner, Inge

2017-07-01

Environmental risk assessment is an essential part of the approval process for pesticides. Exposure concentrations are compared with ecotoxicological data obtained from standardized laboratory studies and, if available, from field studies to determine the risk of a substance or formulation for aquatic communities. Predicted concentrations in surface waters are derived using, for example, the European FOrum for the Co-ordination of pesticide fate models and their USe (FOCUS) or the German Exposit models, which distinguish between exposure to dissolved and particle-associated pesticide concentrations, because the dissolved concentration is thought to be the best predictor of bioavailability and toxicity. Water and particle-associated concentrations are estimated based on the organic carbon-water partitioning coefficient (K OC ). This review summarizes published information on the influence of natural suspended solids on bioavailability and toxicity of pesticides to aquatic organisms (algae, invertebrates and fish), and the value of log K OC and log K OW (octanol-water coefficient) as sole predictors of the bioavailable fraction is discussed. The information showed that: 1) the quality and origin of suspended solids played an important role in influencing pesticide bioavailability and toxicity; 2) a decrease in toxicity due to the presence of suspended solids was shown only for pyrethroid insecticides with log K OW greater than 5, but the extent of this reduction depended on particle concentration and size, and potentially also on the ecotoxicological endpoint; 3) for pesticides with a log K OW less than 3 (e.g., triazines, carbamates, and organophosphates), the impact of particles on bioavailability and toxicity is small and species dependent; and 4) pesticide bioavailability is greatly influenced by the test species and their physiology (e.g., feeding behavior or digestion). We conclude that exposure of aquatic organisms to pesticides and environmental risk of many pesticides might be underestimated in prospective risk assessment, when predicted environmental concentration is estimated based on the K OC of a compound. Integr Environ Assess Manag 2017;13:585-600. © 2016 SETAC. © 2016 SETAC.

Assimilation efficiency and toxicokinetics of 14C-lindane in the terrestrial isopod Porcellionides pruinosus: the role of isopods in degradation of persistent soil pollutants.

PubMed

Loureiro, Susana; Sousa, J P; Nogueira, A J A; Soares, A M V M

2002-12-01

An achievable way to evaluate the bioavailability of a certain toxic in the environment is to measure the concentration inside soil organisms. Non-target saprotrophic organisms like isopods are often exposed to agrochemicals or other kind of persistent chemicals. In this study the isopod Porcellionides pruinosus was exposed to a constant concentration of Lindane (gamma-HCH) via food. Using toxicokinetic models the bioaccumulation and fate of the pesticide by isopods was assessed and compared with previous studies, where an unexpected decrease in gamma-HCH concentration was observed. Animal body burdens showed higher values, and a lower assimilation rate constant, although the elimination rate constant was twice the value previously observed. It was also observed that a significant amount of gamma-HCH had an unknown fate. To discover its possible destiny, a factorial experiment was carried out using two types of CO2 traps and contaminated leaves in the presence and absence of isopods. It was concluded that isopod activity might have been responsible for a more rapid biotransformation of gamma-HCH in leaves, since the amount of the pesticide is reduced in their presence.

42nd Congress of the "Groupe Français des Pesticides" (French Group of Pesticide research--GFP 2012) ENSIP, Poitiers, France, 30 May-1 June 2012.

PubMed

Chollet, Jean-François; Couderchet, Michel; Bonnemain, Jean-Louis

2014-04-01

The 42nd congress of the "Groupe Français des Pesticides" (French Group of Pesticide research--GFP 2012) took place 30 May-1 June at the "École Nationale Supérieure d’Ingénieurs de Poitiers" (ENSIP), a French generalist engineering grande école in Poitiers. Its focus is on the protection of the environment and is part of the University of Poitiers, one of the oldest universities in Europe. GFP is an annual conference where the latest developments in the field of pesticide research are presented. The topics most commonly discussed mainly concern environmental quality, monitoring, fate, and transfer of pesticides in the environment or risks associated with use of pesticides, but every year a key theme sets the tone. For this 42nd edition, the theme "Innovative strategies for plant protection" was retained.

Introduction to Biotechnology Regulation for Pesticides

EPA Pesticide Factsheets

Includes data requirements for the registration of plant-incorporated protectants (PIP), gene flow assessment, ecological non-target organism risk assessment process, environmental fate, insect resistance management in Bt crops.

Conceptual Model for the Transport of Energetic Residues from Surface Soil to Groundwater by Range Activities

DTIC Science & Technology

2006-11-01

Fate and Toxicity. Journal of Soil Contamination. 6:561–568. Basunia, S., and S. Landsberger. 2001. Contents and leachability of heavy metals (Pb, Cu...concentrations of certain inorganics may be toxic. Dissolved organic matter, whether from natural or anthropogenic sources , may chelate with metals and...or pesticides are observed in soil or groundwater, their likely source is unrelated to the usage of military munitions. ERDC/CRREL TR-06-18 11

Organochlorine pesticides, their toxic effects on living organisms and their fate in the environment

PubMed Central

Megha, Pankajshan; Sreedev, Puthur

2016-01-01

Organochlorine (OC) pesticides are synthetic pesticides widely used all over the world. They belong to the group of chlorinated hydrocarbon derivatives, which have vast application in the chemical industry and in agriculture. These compounds are known for their high toxicity, slow degradation and bioaccumulation. Even though many of the compounds which belong to OC were banned in developed countries, the use of these agents has been rising. This concerns particularly abuse of these chemicals which is in practice across the continents. Though pesticides have been developed with the concept of target organism toxicity, often non-target species are affected badly by their application. The purpose of this review is to list the major classes of pesticides, to understand organochlorine pesticides based on their activity and persistence, and also to understand their biochemical toxicity. PMID:28652852

Delayed degradation in soil of foliar herbicides glyphosate and sulcotrione previously absorbed by plants: consequences on herbicide fate and risk assessment.

PubMed

Doublet, Jérémy; Mamy, Laure; Barriuso, Enrique

2009-10-01

Following application, pesticides can be intercepted and absorbed by weeds and/or crops. Plants containing pesticides residues may then reach the soil during the crop cycle or after harvest. However, the fate in soil of pesticides residues in plants is unknown. Two commonly used foliar herbicides, glyphosate and sulcotrione, (14)C-labeled, were applied on leaves of oilseed rape and/or maize, translocation was studied, and then soil incubations of aerial parts of plants containing herbicides residues were performed. Soil treated directly with herbicides was used as control. The effects of adjuvants on herbicide plant-absorption and subsequent soil-degradation were also investigated comparing herbicides application as active ingredients and as commercial formulations. The fate in soil of herbicides residues in plants was different from that of control, and different for glyphosate and sulcotrione. Mineralization in soil of glyphosate in crops decreased compared to control, and amounts of (14)C-extractable residues, mainly composed by the metabolite aminomethylphosphonic acid (AMPA), and non-extractable residues (NER) increased. In contrast, mineralization in soil of sulcotrione in maize increased compared to control, with a decrease in the (14)C-extractable residues and an increase in NER. The fate of both herbicides was influenced by the type of plant organ in which herbicide was incorporated, because of differences in herbicides bioavailability and organs biodegradability, but not by adjuvants. Absorption of both herbicides in plant delays their subsequent soil-degradation, and particularly, glyphosate persistence in soil could increase from two to six times. The modifications of herbicide degradation in soil due to interception by plants should be considered for environmental risks assessment.

Pesticide interactions with soil affected by olive mill wastewater (OMW): how strong and long-lasting is the OMW effect?

NASA Astrophysics Data System (ADS)

Keren, Yonatan; Borisover, Mikhail; Schaumann, Gabriele E.; Diehl, Dörte; Tamimi, Nisreen; Bukhanovsky, Nadezhda

2017-04-01

Sorption interactions with soils are well known to control the environmental fate of multiple organic compounds including pesticides. Pesticide-soil interactions may be affected by organic amendments or organic matter (OM)-containing wastewater brought to the field. Specifically, land spreading of olive mill wastewater (OMW), occurring intentionally or not, may also influence pesticide-soil interactions. The effects of the OMW disposed in the field on soil properties, including their ability to interact with pesticides, become of great interest due to the increasing demand for olive oil and a constant growth of world oil production. This paper summarizes some recent findings related to the effect of prior OMW land application on the ability of soils to interact with the organic compounds including pesticides, diuron and simazine. The major findings are as following: (1) bringing OMW to the field increases the potential of soils to sorb non-ionized pesticides; (2) this sorption increase may not be related solely to the increase in soil organic carbon content but it can reflect also the changes in the soil sorption mechanisms; (3) increased pesticide interactions with OMW-affected soils may become irreversible, due, assumedly, to the swelling of some components of the OMW-treated soil; (4) enhanced pesticide-soil interactions mitigate with the time passed after the OMW application, however, in the case of diuron, the remaining effect could be envisioned at least 600 days after the normal OMW application; (5) the enhancement effect of OMW application on soil sorption may increase with soil depth, in the 0-10 cm interval; (6) at higher pesticide (diuron) concentrations, larger extents of sorption enhancement, following the prior OMW-soil interactions, may be expected; (7) disposal of OMW in the field may be seasonal-dependent, and, in the case studied, it led to more distinct impacts on sorption when carried out in spring and winter, as compared with summer. It appears that when examining the fate of organic compounds in soil environments affected by OMW, more attention is needed to (a) the effect of the OMW penetration into the depth on soil-pesticide interactions; (b) long-term and seasonal-dependent effects of OMW application.

Occurrence and fate of pesticides in the Argentine stretch of the Paraguay-Paraná basin.

PubMed

Etchegoyen, M A; Ronco, A E; Almada, P; Abelando, M; Marino, D J

2017-02-01

The Argentine stretch of the del Plata basin crosses regions devoted to extensive and intensive agriculture mostly with chemical pest control. The utilization of pesticides in the region has increased 900% in the last two decades associated with the introduction of biotech crops and direct-seeding techniques. Our objective was to study the occurrence, concentration, and fate of pesticides in surface water and bottom sediments of the principal tributaries and main watercourse of the Paraguay-Paraná River. We sampled 22 sites in the distal positions of the main affluents and main watercourse of the Paraná and report here results from two monitoring campaigns (2010-2012). Surface water and bottom sediments were analyzed according to standardized methods by matrix-solid-phase dispersion and liquid-liquid extraction, respectively. Twenty-three pesticide compounds were analyzed by gas chromatography. The results from both campaigns indicated a generalized but variable distribution in the concentrations detected throughout the basin. The ranges of total measured pesticide concentrations in water and sediments were, respectively, 0.004-6.62 μg/l and 0.16-221.3 μg/kg dry weight. Endosulfans, cypermethrin, and chlorpyrifos were ubiquitous compounds in both environmental compartments and quantitatively the most relevant. All concentrations detected in water were over the recommended guidelines for the protection of aquatic biota. The partitioning indicated a higher affinity for the sediments. Agricultural activity is the source of pesticide-pollution loads, transported by tributaries that reach the main watercourse and alter the quality of the aquatic ecosystem.

Chemical fate and transport of atrazine in soil gravel materials at agrichemical distribution facilities

USGS Publications Warehouse

Roy, W.R.; Krapac, I.G.; Chou, S.-F.J.

1999-01-01

The gravel commonly used to cover parking lots and roadways at retail agrichemical facilities may contain relatively large concentrations of pesticides that resulted from past management problems. These pesticides may threaten groundwater quality. Previous studies, however, suggested that the pesticides had not moved from the gravel in several sample profiles. Excavations at a closed facility revealed tremendous variability in pesticide distribution within the site. Pesticides were present below the gravel in two profiles, but the mechanism(s) for their movement were not clear. The objectives of this study were to investigate how the physical and chemical properties of the gravel influence the environmental fate of atrazine. All of the gravel samples collected and characterized contained atrazine and sufficient organic C to adsorb significant amounts of atrazine, thus retarding its movement through the gravel. Laboratory column leaching experiments, however, suggested that much of the atrazine should leach from the gravel within a year or two. A field-scale test plot was constructed to study how atrazine moves through the gravel under controlled conditions. Atrazine was "spilled" in the test plot. Atrazine moved from the gravel both vertically and horizontally. It appears that formulated product spilled on gravel will leach. A single discrete spill can give rise to phantom spills whose occurrence and distribution is not related to any specific pesticide-management practice. The apparent lack of atrazine leaching from gravel appeared to be a transient phenomenon and/or the result of sampling limitations in previous studies. The contaminated gravel clearly poses a risk to groundwater quality.

NAFTA Guidance Document for Conducting Terrestrial Field Dissipation Studies

EPA Pesticide Factsheets

Harmonized guidance for TFD studies that demonstrate transformation, transport and fate of pesticides under representative actual use conditions. Field studies substantiate physicochemical, mobility and biotransformation data from laboratory studies.

Little field evidence of direct acute and short-term effects of current pesticides on the grey partridge.

PubMed

Millot, Florian; Berny, Philippe; Decors, Anouk; Bro, Elisabeth

2015-07-01

Direct lethal and sublethal effects of pesticides on farmland birds' populations are recurring questions and largely debated. In this context, we conducted an innovative study combining radiotelemetry, farmer surveys, residue analyses on carcasses and modelling to assess the unintentional effects of pesticides on terrestrial birds. We chose the grey partridge Perdix perdix as a case study because this typical bird of European cereal ecosystems is highly exposed to pesticides. In this paper we focused on acute and short-term impacts of pesticides on adult mortality during spring and summer in a one-substance approach (multiple exposure were not studied here) but for a large variety of active substances (a.s.) actually used in cultivated farmland of Northern France. The fate and the location of 529 partridges were monitored twice a day from early March to late August 2010 and 2011 on 12 sites (14,500 ha). Their daily potential exposure to 183 a.s. was determined by overlapping birds' habitat use and daily pesticide application data. Based on this procedure, we calculated mortality rates within 10 days following a potential exposure for 157 different a.s.. 5 a.s. were associated with a "10-day mortality rate" higher than 10% but a single one (thiacloprid) is reported to be highly toxic to birds. We recorded 261 mortalities among which 94 carcasses were in suitable condition for residue analyses. We detected at least one a.s in 39.4% of carcasses. However, only 2 mortality cases were attributed to poisoning (carbofuran). Furthermore, modelling results showed that these lethal pesticide-related poisonings decreased the population growth rate by less than 1%. In conclusion, we did not point out important direct acute and short-term effects of pesticides currently used by farmers during the breeding season on the grey partridge. This is discussed with regards to the complexity of potential effects in operational conditions. Copyright © 2015 Elsevier Inc. All rights reserved.

Considerations of nano-QSAR/QSPR models for nanopesticide risk assessment within the European legislative framework.

PubMed

Villaverde, Juan José; Sevilla-Morán, Beatriz; López-Goti, Carmen; Alonso-Prados, José Luis; Sandín-España, Pilar

2018-09-01

The European market for pesticides is currently legislated through the well-developed Regulation (EC) No. 1107/2009. This regulation promotes the competitiveness of European agriculture, recognizing the necessity of safe pesticides for human and animal health and the environment to protect crops against pests, diseases and weeds. In this sense, nanotechnology can provide a tremendous opportunity to achieve a more rational use of pesticides. However, the lack of information regarding nanopesticides and their fate and behavior in the environment and their effects on human and animal health is inhibiting rapid nanopesticide incorporation into European Union agriculture. This review analyzes the recent state of knowledge on nanopesticide risk assessment, highlighting the challenges that need to be overcame to accelerate the arrival of these new tools for plant protection to European agricultural professionals. Novel nano-Quantitative Structure-Activity/Structure-Property Relationship (nano-QSAR/QSPR) tools for risk assessment are analyzed, including modeling methods and validation procedures towards the potential of these computational instruments to meet the current requirements for authorization of nanoformulations. Future trends on these issues, of pressing importance within the context of the current European pesticide legislative framework, are also discussed. Standard protocols to make high-quality and well-described datasets for the series of related but differently sized nanoparticles/nanopesticides are required. Copyright © 2018 Elsevier B.V. All rights reserved.

Atmospheric deposition of current-use and historic-use pesticides in snow at National Parks in the Western United States

USGS Publications Warehouse

Hageman, K.J.; Simonich, S.L.; Campbell, D.H.; Wilson, G.R.; Landers, D.H.

2006-01-01

The United States (U.S.) National Park Service has initiated research on the atmospheric deposition and fate of semi-volatile organic compounds in its alpine, sub-Arctic, and Arctic ecosystems in the Western U.S. Results for the analysis of pesticides in seasonal snowpack samples collected in spring 2003 from seven national parks are presented herein. From a target analyte list of 47 pesticides and degradation products, the most frequently detected current-use pesticides were dacthal, chlorpyrifos, endosulfan, and ??- hexachlorocyclohexane, whereas the most frequently detected historic-use pesticides were dieldrin, ??-hexachlorocyclohexane, chlordane, and hexachlorobenzene. Correlation analysis with latitude, temperature, elevation, particulate matter, and two indicators of regional pesticide use reveal that regional current and historic agricultural practices are largely responsible for the distribution of pesticides in the national parks in this study. Pesticide deposition in the Alaskan parks is attributed to long-range transport because there are no significant regional pesticide sources. The percentage of total pesticide concentration due to regional transport (%RT) was calculated for the other parks. %RT was highest at parks with higher regional cropland intensity and for pesticides with lower vapor pressures and shorter half-lives in air. ?? 2006 American Chemical Society.

Validation of The Scenarios Designed For The Eu Registration of Pesticides

NASA Astrophysics Data System (ADS)

Piñeros Garcet, J. D.; de Nie, D.; Vanclooster, M.; Tiktak, A.; Klein, M.

As part of recent efforts to harmonise registration procedures for pesticides within the EU, a set of uniform principles were developed, setting out the detailed evaluation and decision making criteria for pesticide registration. The EU directive 91/414/EEC places great importance on the use of validated models to calculate Predicted Envi- ronmental Concentrations (PECs), as a basis for assessing the environmental risks and health effects. To be used in a harmonised registration process, the quality of PEC modelling needs to be assured. Quality assurance of mathematical modelling implies, amongst others, the validation of the environmental modelling scenarios. The FOrum for the CO-ordination of pesticide fate models and their USe (FOCUS), is the cur- rent platform where common modelling methodologies are designed and subjected for approval to the European authorities. In 2000, the FOCUS groundwater scenarios working group defined the procedures for realising tier 1 PEC groundwater calcula- tions for the active substances of plant protection products at the pan-european level. The procedures and guidelines were approved by the Standing Committee on Plant Health, and are now recommended for tier 1 PEC groundwater calculations in the reg-istration dossier. Yet, the working group also identified a range of uncertainties related to the validity of the present leaching scenarios. To mitigate some of these problems,the EU R&D project APECOP was designed and approved for support in the frame-work of the EU-FP5-Quality of Life Programme. One of the objectives of the project is to evaluate the appropriateness of the current Tier 1 groundwater scenarios. In this paper, we summarise the methodology and results of the scenarios validation.

Validation of The Scenarios Designed For The Eu Registration of Pesticides

NASA Astrophysics Data System (ADS)

Piñeros Garcet, J. D.; de Nie, D.; Vanclooster, M.; Tiktak, A.; Klein, M.; Jones, A.

As part of recent efforts to harmonise registration procedures for pesticides within the EU, a set of uniform principles were developed, setting out the detailed evaluation and decision making criteria for pesticide registration. The EU directive 91/414/EEC places great importance on the use of validated models to calculate Predicted Envi- ronmental Concentrations (PECs), as a basis for assessing the environmental risks and health effects. To be used in a harmonised registration process, the quality of PEC modelling needs to be assured. Quality assurance of mathematical modelling implies, amongst others, the validation of the environmental modelling scenarios. The FOrum for the CO-ordination of pesticide fate models and their USe (FOCUS), is the cur- rent platform where common modelling methodologies are designed and subjected for approval to the European authorities. In 2000, the FOCUS groundwater scenarios working group defined the procedures for realising tier 1 PEC groundwater calcula- tions for the active substances of plant protection products at the pan-european level. The procedures and guidelines were approved by the Standing Committee on Plant Health, and are now recommended for tier 1 PEC groundwater calculations in the reg- istration dossier. Yet, the working group also identified a range of uncertainties related to the validity of the present leaching scenarios. To mitigate some of these problems, the EU R&D project APECOP was designed and approved for support in the frame- work of the EU-FP5-Quality of Life Programme. One of the objectives of the project is to evaluate the appropriateness of the current Tier 1 groundwater scenarios. In this paper, we summarise the methodology and results of the scenarios validation.

Volatile organic compounds in pesticide formulations: Methods to estimate ozone formation potential

NASA Astrophysics Data System (ADS)

Zeinali, Mazyar; McConnell, Laura L.; Hapeman, Cathleen J.; Nguyen, Anh; Schmidt, Walter F.; Howard, Cody J.

2011-05-01

The environmental fate and toxicity of active ingredients in pesticide formulations has been investigated for many decades, but relatively little research has been conducted on the fate of pesticide co-formulants or inerts. Some co-formulants are volatile organic compounds (VOCs) and can contribute to ground-level ozone pollution. Effective product assessment methods are required to reduce emissions of the most reactive VOCs. Six emulsifiable concentrate pesticide products were characterized for percent VOC by thermogravimetric analysis (TGA) and gas chromatography-mass spectrometry (GC-MS). TGA estimates exceeded GC-MS by 10-50% in all but one product, indicating that for some products a fraction of active ingredient is released during TGA or that VOC contribution was underestimated by GC-MS. VOC profiles were examined using TGA-Fourier transform infrared (FTIR) evolved gas analysis and were compared to GC-MS results. The TGA-FTIR method worked best for products with the simplest and most volatile formulations, but could be developed into an effective product screening tool. An ozone formation potential ( OFP) for each product was calculated using the chemical composition from GC-MS and published maximum incremental reactivity ( MIR) values. OFP values ranged from 0.1 to 3.1 g ozone g -1 product. A 24-h VOC emission simulation was developed for each product assuming a constant emission rate calculated from an equation relating maximum flux rate to vapor pressure. Results indicate 100% VOC loss for some products within a few hours, while other products containing less volatile components will remain in the field for several days after application. An alternate method to calculate a product OFP was investigated utilizing the fraction of the total mass of each chemical emitted at the end of the 24-h simulation. The ideal assessment approach will include: 1) unambiguous chemical composition information; 2) flexible simulation models to estimate emissions under different management practices; and 3) accurate reactivity predictions.

METHODS DEVELOPMENT FOR THE ANALYSIS OF CHIRAL PESTICIDES

EPA Science Inventory

Chiral compounds exist as a pair of nonsuperimposable mirror images called enantiomers. Enantiomers have identical physical-chemical properties, but their interactions with other chiral molecules, toxicity, biodegradation, and fate are often different. Many pharmaceutical com...

Applicability of ELISA-based Determination of Pesticides for Groundwater Quality Monitoring

NASA Astrophysics Data System (ADS)

Tsuchihara, Takeo; Yoshimoto, Shuhei; Ishida, Satoshi; Imaizumi, Masayuki

The principals and procedures of ELISA (Enzyme-linked Immunosorbent Assay)-based determination of pesticides (Fenitrothion) in environmental samples were reviewed, and the applicability of the ELISA method for groundwater quality monitoring were validated through the experimental tracer tests in soil columns and the field test in Okinoerabu Island. The test results showed that the ELISA method could be useful not only for screening but also for quantitative analysis of pesticides. In the experimental tracer tests in soil columns, the retardation of pesticides leaching compared with conservative tracers were observed. In the field test, the contamination of the pesticide was detected in groundwater samples in Okinoerabu Island, even though the targeted pesticide was considered to be applied to the upland field 4 months ago. In order to investigate the transport and fate of pesticides in groundwater taking into account retardation from the field to groundwater table and the residue in groundwater, continuous observations of pesticides in groundwater are in a strong need, and the ELISA method is applicable to the long-term quality groundwater monitoring.

Gas Chromatography-Infrared (GC-IR) Applications In Pesticide Chemistry

NASA Astrophysics Data System (ADS)

Kalasinsky, Kathryn S.

1981-10-01

After pesticides in bait formulation have been applied in the field, it is important that the fate of that amount of toxicant which has not been consumed by the pest is known. Many of these substances are not compatible with the environment and it is also important that their biodegradation be understood and controlled to a certain extent. In efforts to monitor and direct these reactions GC-IR has been found to be an invaluable tool.

Distributions and fate of chlorinated pesticides, biomarkers and polycyclic aromatic hydrocarbons in sediments along a contamination gradient from a point-source in San Francisco Bay, California

USGS Publications Warehouse

Pereira, W.E.; Hostettler, F.D.; Rapp, J.B.

1996-01-01

The distribution and fate of chlorinated pesticides, biomarkers, and polycyclic aromatic hydrocarbons (PAHs) in surficial sediments along a contamination gradient in the Lauritzen Canal and Richmond Harbor in San Francisco Bay was investigated. Compounds were identified and quantified using gas chromatography-ion trap mass spectrometry. Biomarkers and PAHs were derived primarily from weathered petroleum. DDT was reductively dechlorinated under anoxic conditions to DDD and several minor degradation products, DDMU, DDMS, and DDNU. Under aerobic conditions, DDT was dehydrochlorinated to DDE and DBP. Aerobic degradation of DDT was diminished or inhibited in zones of high concentration, and increased significantly in zones of lower concentration: Other chlorinated pesticides identified in sediment included dieldrin and chlordane isomers. Multivariate analysis of the distributions of the DDTs suggested that there are probably two sources of DDD. In addition, DDE and DDMU are probably formed by similar mechanisms, i.e. dehydrochlorination. A steep concentration gradient existed from the Canal to the Outer Richmond Harbor, but higher levels of DDD than those found in the remainder of the Bay indicated that these contaminants are transported on particulates and colloidal organic matter from this source into San Francisco Bay. Chlorinated pesticides and PAHs may pose a potential problem to biota in San Francisco Bay.

Evaluation of soil contamination in intensive agricultural areas by pesticides and organic pollutants: south-eastern Spain as a case study.

PubMed

Plaza-Bolaños, Patricia; Padilla-Sánchez, Juan Antonio; Garrido-Frenich, Antonia; Romero-González, Roberto; Martínez-Vidal, José Luis

2012-04-01

A comprehensive survey of the occurrence and fate of pesticides and organic contaminants in soils from an intensive agricultural area devoted to horticultural production in plastic-based greenhouses has been performed to determine if the operation under integrated pest management practices has contributed to reduce the levels of these compounds. Almería province (south-eastern Spain) was selected for the case study. 38 agricultural soil samples (each sample corresponds to an independent private greenhouse) of areas working under integrated pest management (IPM) programs have been analyzed in order to evaluate their contamination fate. Sampling was designed to cover an area of about 400 km(2). Pesticides, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), phenolic compounds and di-(2-ethylhexyl)phthalate (DEHP) were monitored. The obtained results were compared to other studies reported in Spain and Europe. Among relevant persistent pesticides, DDTs and endosulfans were mainly found and the results indicated historical application, although recent application of endosulfan was rarely detected. PAHs were also found but to a lesser extent and derived from pyrogenic sources. DEHP levels were considerably higher in comparison to the other monitored analytes. The evaluation revealed that despite the use of IPM programs, pesticide and organic contaminants are still being detected in this type of agricultural soil, although at relatively low concentration levels. In general, the contamination rate was similar or lower in comparison to other agricultural areas from nearby regions or countries. However, further monitoring studies should be carried out to establish the possible reduction in contamination by the selected compounds.

Mineralization of isoproturon, mecoprop and acetochlor in a deep unsaturated limestone and sandy aquifer.

PubMed

Janniche, G S; Lindberg, E; Mouvet, C; Albrechtsen, H-J

2010-11-01

Isoproturon (N,N-dimethyl-N'-[4-(1-methylethyl)phenyl]urea), mecoprop (MCPP) (2-(4-chloro-2-methylphenoxy)propanoic acid) and acetochlor (2-chloro-N-(2-ethoxymethyl)-N-(2-ethyl-6-methylphenyl)acetamide) are agricultural pesticides that may leach through the vadose zone down to groundwater. Sediment samples were collected from intact sediment cores from 0 to 59 m below surface, including soil, unsaturated limestone and aquifer sand. In the unsaturated limestone, the initial pesticide concentrations (0.5-100 μg kg(-1)) did not systematically affect the proportion of mineralized pesticides or the kinetics. However, in the aquifer, mecoprop and to some degree isoproturon mineralization was found to increase with increasing initial concentration (0.5-100 μg L(-1) equivalent to 1-220 μg kg(-1)) demonstrating the importance of using environmentally relevant concentrations when predicting pesticide fate. The mineralization of isoproturon, mecoprop and acetochlor was studied in 40 samples at low concentrations (1-3 μg L(-1)) and specific pesticide-mineralizing bacteria were enumerated using 14C-MPN. Presence of the mineralizers documented a degradation potential of the pesticides within the catchment. The number of mineralizers varied from <0.18 to >16000 g(-1) and was not found to correlate with depth. Mecoprop, isoproturon and acetochlor were substantially mineralized in the soils (19-44% after 8months incubation at 1 μg kg(-1)), in sub-surface unsaturated limestone samples (≤2% for acetochlor, ≤21% for isoproturon and ≤31% for mecoprop) and in aquifer samples (4-28% for mecoprop, ≤4.7% for isoproturon and ≤5.6% for acetochlor). The finding of isoproturon and acetochlor mineralization in deep aquifers is novel and important for the evaluation of the fate of these pesticides, as even low mineralization rates can be important in aquifers exhibiting long residence times. Copyright © 2010 Elsevier Ltd. All rights reserved.

40 CFR 161.20 - Overview.

Code of Federal Regulations, 2010 CFR

2010-07-01

... product chemistry, residue chemistry, environmental fate, toxicology, reentry protection, aerial drift... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Overview. 161.20 Section 161.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS DATA REQUIREMENTS...

Occurrence and distribution study of residues from pesticides applied under controlled conditions in the field during rice processing.

PubMed

Pareja, Lucía; Colazzo, Marcos; Pérez-Parada, Andrés; Besil, Natalia; Heinzen, Horacio; Böcking, Bernardo; Cesio, Verónica; Fernández-Alba, Amadeo R

2012-05-09

The results of an experiment to study the occurrence and distribution of pesticide residues during rice cropping and processing are reported. Four herbicides, nine fungicides, and two insecticides (azoxystrobin, byspiribac-sodium, carbendazim, clomazone, difenoconazole, epoxiconazole, isoprothiolane, kresoxim-methyl, propanil, quinclorac, tebuconazole, thiamethoxam, tricyclazole, trifloxystrobin, λ-cyhalotrin) were applied to an isolated rice-crop plot under controlled conditions, during the 2009-2010 cropping season in Uruguay. Paddy rice was harvested and industrially processed to brown rice, white rice, and rice bran, which were analyzed for pesticide residues using the original QuEChERS methodology and its citrate variation by LC-MS/MS and GC-MS. The distribution of pesticide residues was uneven among the different matrices. Ten different pesticide residues were found in paddy rice, seven in brown rice, and eight in rice bran. The highest concentrations were detected in paddy rice. These results provide information regarding the fate of pesticides in the rice food chain and its safety for consumers.

Tropical surface water quality studies: Implications for the aquatic fate of N-methyl carbamate pesticides.

PubMed

Ha, Bao; Zamini, Leili; Monn, Jeremy; Njoroge, Samuel; Thimo, Laban; Ondeti, Maria; Murungi, Jane I; Muhoro, Clare N

2018-03-04

Water quality assessment was conducted on the Ruiru River, a tributary of an important tropical river system in Kenya, to determine baseline river conditions for studies on the aquatic fate of N-methyl carbamate (NMC) pesticides. Measurements were taken at the end of the long rainy season in early June 2013. Concentrations of copper (0.21-1.51 ppm), nitrates (2.28-4.89 ppm) and phosphates (0.01-0.50 ppm) were detected at higher values than in uncontaminated waters, and attributed to surface runoff from agricultural activity in the surrounding area. Concentrations of dissolved oxygen (8-10 ppm), ammonia (0.02-0.22 ppm) and phenols (0.19-0.83 ppm) were found to lie within normal ranges. The Ruiru River was found to be slightly basic (pH 7.08-7.70) with a temperature of 17.8-21.2°C. The half-life values for hydrolysis of three NMC pesticides (carbofuran, carbaryl and propoxur) used in the area were measured under laboratory conditions, revealing that rates of decay were influenced by the electronic nature of the NMCs. The hydrolysis half-lives at pH 9 and 18°C decreased in the order carbofuran (57.8 h) > propoxur (38.5 h) > carbaryl (19.3 h). In general, a decrease in the electron density of the NMC aromatic ring increases the acidity of the N-bound proton removed in the rate-limiting step of the hydrolysis mechanism. Our results are consistent with this prediction, and the most electron-poor NMC (carbaryl) hydrolyzed fastest, while the most electron-rich NMC (carbofuran) hydrolyzed slowest. Results from this study should provide baseline data for future studies on NMC pesticide chemical fate in the Ruiru River and similar tropical water systems.

Characterization of the Fate and Biotransformation of Fluorochemicals in AFFF-Contaminated Groundwater at Fire/Crash Testing Military Sites

DTIC Science & Technology

2017-04-10

L that remain above health advisory 56 levels of 1 µg/L 11. These areas also may serve as reservoirs for fluorinated compounds because 57 partially...in direct contrast to anionic pesticide sorption experiments, which found an increase in Kd with increasing AEC.37,79 The sorption of the...are less frequently studied, but zwitterionic pesticide sorption experiments found either an increase80 or no change81 in sorption with increasing

BIODEGRADATION OF ATRAZINE IN SUBSURFACE ENVIRONMENTS

EPA Science Inventory

The pesticide atrazine is frequently detected in ground water, including ground water used as drinking water. Little information is available on the fate of atrazine in the subsurface, including its biodegradability. The objectives of this study were to evaluate the biodegradabil...

Pesticides in Ground Water of Central and Western Maryland

USGS Publications Warehouse

Ator, Scott W.; Reyes, Betzaida

2008-01-01

Selected pesticides and degradates (products of pesticide degradation) are detectable in ground water in many parts of central and western Maryland, although concentrations are generally less than 0.1 micrograms per liter. Ground-water samples collected recently (1994-2003) from 72 wells in areas of Maryland underlain by consolidated carbonate, crystalline, or siliciclastic aquifers (areas north and west of the Fall Line) were analyzed for selected pesticides and degradates. Pesticides were typically detected in mixtures of multiple compounds in ground water, and degradates were commonly detected, often at greater concentrations than their respective parent compounds. No pesticides were observed at concentrations greater than established standards for drinking water, and nearly all observed concentrations were below other health-based guidelines. Although such standards and guidelines are generally much greater than measured concentrations in ground water, they do not exist for many detected compounds (particularly degradates), or for mixtures of multiple compounds. The distribution of pesticides and degradates in ground water is related to application practices, as well as chemical and environmental factors that affect the fate and movement of individual compounds.

A GIS-based approach to prevent contamination of groundwater at regional scale

NASA Astrophysics Data System (ADS)

Balderacchi, M.; Vischetti, C.; di Guardo, A.; Trevisan, M.

2009-04-01

Sustainable development is a fundamental objective of the European Union. Since 1991, the use of numerical models has been used to assess the environmental fate of pesticides (directive 91/414 EC). Since then, new approaches to assess pesticide contamination have been developed. This is an ongoing process, with approaches getting increasingly close to reality. Actually, there is a new challenge to integrate the most advanced and cost-effective monitoring strategies with simulation models so that reliable indicators of unsaturated flow and transport can be suitably mapped and coupled with other indicators related to productivity and sustainability. The most relevant role of GIS in the analysis of pesticide fate in soil is its application to process together input data and the results of distribution model based simulations of pesticide transport. FitoMarche is a GIS-based software tool that estimates pesticide movement in the unsaturated zone using MACRO 5 and it is able to simulate complex and real crop rotations at the regional scale. Crop rotation involves the sequential production of different plant species on the same land, every crop is characterized by different agricultural practices that involve the use of different pesticides at different doses. FitoMarche extracts MACRO input data from a series of geographic data sets (shapefiles) and an internal database, writes input files for MACRO, executes the simulation and extracts solute and water fluxes from MACRO output files. The study has been performed in the Marche region, located in central Italy along the Adriatic coast. Soil, climate, land use shapefiles were provided from public authorities, crop rotation schemes were estimated from ISTAT (the national statistics institute) 5th agricultural census database using a municipality detail and agricultural practices following the local customs. Two herbicides have been tested: "A" is employed on maize crop, and "B" on maize, sunflower and sugarbeet. In the first part the study focused of a definition of an indicator of groundwater contamination. The probably to exceed the groundwater quality endpoint has been chosen and it has been developed according a probabilistic approach and following a lognormal distribution of the data. After that the effect of crop rotation on pesticide leaching has been evaluated by a stepwise procedure. The tier 1 was the worst case in which the whole region is considered cropped with maize, therefore the pesticide application is every year on the crop with the highest application rate, whereas the tier 2 was a first refinement of the previous tier, the pesticide application was still every year but only in to the areas with the presence of authorised crop fore the assessed pesticide and with a crop LUA (land under agriculture) ratio higher than 10%. In the passage from tier 1 to tier 2 a contemporaneous reduction of simulated surface and pesticide leaching occurred because a relationship exists between agriculture and pesticide use. The step 3 considered a pesticide timing based on typical crop rotations. Te application followed label doses and was every time an authorised crop was found in the rotation. The passage to step 3 allowed a further percolation reduction. Step 3 blind simulations have been plotted as maps and matched with the results of the regional environment agency monitoring plan. A good correspondence between prediction and observation has got. Nevertheless herbicide "A" was detected in a larger area than assumed to be cropped with maize. However, in the past this compound was authorized for application to crops other than maize and was also used extensively in non-agricultural applications. Herbicide "B" was also detected in two wells located in areas not considered vulnerable. In the first well, water was sampled three times and the compound was detected once, in the other water was sampled once and the compound was detected. In this case point contamination, could be the origin of that. These pesticides were also researched in areas in which there is not application. This suggest that GIS approach can allow the design of new agrochemical monitoring plans that focus resources in areas with the highest probability of detection, reducing the cost to the community, and increasing the scientific value of the data collected. In the future, when well validated geographic data sets are available, it will also be possible to distinguish between point and diffuse contamination.

Pesticide nonextractable residue formation in soil: insights from inverse modeling of degradation time series.

PubMed

Loos, Martin; Krauss, Martin; Fenner, Kathrin

2012-09-18

Formation of soil nonextractable residues (NER) is central to the fate and persistence of pesticides. To investigate pools and extent of NER formation, an established inverse modeling approach for pesticide soil degradation time series was evaluated with a Monte Carlo Markov Chain (MCMC) sampling procedure. It was found that only half of 73 pesticide degradation time series from a homogeneous soil source allowed for well-behaved identification of kinetic parameters with a four-pool model containing a parent compound, a metabolite, a volatile, and a NER pool. A subsequent simulation indeed confirmed distinct parameter combinations of low identifiability. Taking the resulting uncertainties into account, several conclusions regarding NER formation and its impact on persistence assessment could nonetheless be drawn. First, rate constants for transformation of parent compounds to metabolites were correlated to those for transformation of parent compounds to NER, leading to degradation half-lives (DegT50) typically not being larger than disappearance half-lives (DT50) by more than a factor of 2. Second, estimated rate constants were used to evaluate NER formation over time. This showed that NER formation, particularly through the metabolite pool, may be grossly underestimated when using standard incubation periods. It further showed that amounts and uncertainties in (i) total NER, (ii) NER formed from the parent pool, and (iii) NER formed from the metabolite pool vary considerably among data sets at t→∞, with no clear dominance between (ii) and (iii). However, compounds containing aromatic amine moieties were found to form significantly more total NER when extrapolating to t→∞ than the other compounds studied. Overall, our study stresses the general need for assessing uncertainties, identifiability issues, and resulting biases when using inverse modeling of degradation time series for evaluating persistence and NER formation.

Accounting for uncertainty in pedotransfer functions in vulnerability assessments of pesticide leaching to groundwater.

PubMed

Stenemo, Fredrik; Jarvis, Nicholas

2007-09-01

A simulation tool for site-specific vulnerability assessments of pesticide leaching to groundwater was developed, based on the pesticide fate and transport model MACRO, parameterized using pedotransfer functions and reasonable worst-case parameter values. The effects of uncertainty in the pedotransfer functions on simulation results were examined for 48 combinations of soils, pesticides and application timings, by sampling pedotransfer function regression errors and propagating them through the simulation model in a Monte Carlo analysis. An uncertainty factor, f(u), was derived, defined as the ratio between the concentration simulated with no errors, c(sim), and the 80th percentile concentration for the scenario. The pedotransfer function errors caused a large variation in simulation results, with f(u) ranging from 1.14 to 1440, with a median of 2.8. A non-linear relationship was found between f(u) and c(sim), which can be used to account for parameter uncertainty by correcting the simulated concentration, c(sim), to an estimated 80th percentile value. For fine-textured soils, the predictions were most sensitive to errors in the pedotransfer functions for two parameters regulating macropore flow (the saturated matrix hydraulic conductivity, K(b), and the effective diffusion pathlength, d) and two water retention function parameters (van Genuchten's N and alpha parameters). For coarse-textured soils, the model was also sensitive to errors in the exponent in the degradation water response function and the dispersivity, in addition to K(b), but showed little sensitivity to d. To reduce uncertainty in model predictions, improved pedotransfer functions for K(b), d, N and alpha would therefore be most useful. 2007 Society of Chemical Industry

Pesticides in stream sediment and aquatic biota: distribution, trends, and governing factors

USGS Publications Warehouse

Nowell, Lisa H.; Capel, Peter D.

1999-01-01

More than 20 years after the ban of DDT and other organochlorine pesticides, pesticides continue to be detected in air, rain, soil, surface water, bed sediment, and aquatic and terrestrial biota throughout the world. Recent research suggests that low levels of some of these pesticides may have the potential to affect the development, reproduction, and behavior of fish and wildlife, and possibly humans. Pesticides in Stream Sediment and Aquatic Biota: Distribution, Trends, and Governing Factors assesses the occurrence and behavior of pesticides in bed sediment and aquatic biota-the two major compartments of the hydrologic system where organochlorine pesticides are most likely to accumulate. This book collects, for the first time, results from several hundred monitoring studies and field experiments, ranging in scope from individual sites to the entire nation. Comprehensive tables provide concise summaries of study locations, pesticides analyzed, and study outcomes. Comprehensive and extensively illustrated, Pesticides in Stream Sediment and Aquatic Biota: Distribution, Trends, and Governing Factors evaluates the sources, environmental fate, geographic distribution, and long-term trends of pesticides in bed sediment and aquatic biota. The book focuses on organochlorine pesticides, but also assesses the potential for currently used pesticides to be found in bed sediment and aquatic biota. Topics covered in depth include the effect of land use on pesticide occurrence, mechanisms of pesticide uptake and accumulation by aquatic biota, and the environmental significance of observed levels of pesticides in stream sediment and aquatic biota.

Bridging the gap between life cycle inventory and impact assessment for toxicological assessments of pesticides used in crop production.

PubMed

van Zelm, Rosalie; Larrey-Lassalle, Pyrène; Roux, Philippe

2014-04-01

In Life Cycle Assessment (LCA), the Life Cycle Inventory (LCI) provides emission data to the various environmental compartments and Life Cycle Impact Assessment (LCIA) determines the final distribution, fate and effects. Due to the overlap between the Technosphere (anthropogenic system) and Ecosphere (environment) in agricultural case studies, it is, however, complicated to establish what LCI needs to capture and where LCIA takes over. This paper aims to provide guidance and improvements of LCI/LCIA boundary definitions, in the dimensions of space and time. For this, a literature review was conducted to provide a clear overview of available methods and models for both LCI and LCIA regarding toxicological assessments of pesticides used in crop production. Guidelines are provided to overcome the gaps between LCI and LCIA modeling, and prevent the overlaps in their respective operational spheres. The proposed framework provides a starting point for LCA practitioners to gather the right data and use the proper models to include all relevant emission and exposure routes where possible. It is also able to predict a clear distinction between efficient and inefficient management practices (e.g. using different application rates, washing and rinsing management, etc.). By applying this framework for toxicological assessments of pesticides, LCI and LCIA can be directly linked, removing any overlaps or gaps in between the two distinct LCA steps. Copyright © 2013 Elsevier Ltd. All rights reserved.

Environmental exposures to agrochemicals in the Sierra Nevada mountain range

USGS Publications Warehouse

LeNoir, J.; Aston, L.; Data, S.; Fellers, G.; McConnell, L.; Sieber, J.

2000-01-01

The release of pesticides into the environment may impact human and environmental health. Despite the need for environmental exposure data, few studies quantify exposures in urban areas and even fewer determine exposures to wildlife in remote areas. Although it is expected that concentrations in remote regions will be low, recent studies suggest that even low concentrations may have deleterious effects on wildlife. Many pesticides are known to interfere with the endocrine systems of humans and wildlife, adversely affecting growth, development, and behavior. This chapter reviews the fate and transport of pesticides applied in the Central Valley of California and quantifies their subsequent deposition into the relatively pristine Sierra Nevada Mountain Range.

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

NASA Astrophysics Data System (ADS)

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

2011-07-01

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

Guidance for Determining the Acceptability of Environmental Fate Studies Conducted with Foreign Soils

EPA Pesticide Factsheets

International and U.S. soil taxonomical classification systems, distribution of soil orders in the United States, specific criteria to help scientists determine when foreign soils are representative of U.S. soils at intended pesticide use sites.

Assessing the chemical and biological accessibility of the herbicide isoproturon in soil amended with biochar.

PubMed

Sopeña, Fatima; Semple, Kirk; Sohi, Saran; Bending, Gary

2012-06-01

There is considerable current interest in using biochar (BC) as a soil amendment to sequester carbon to mitigate climate change. However, the implications of adding BC to agricultural soil for the environmental fate of pesticides remain unclear. In particular, the effect of biochars on desorption behavior of compounds is poorly understood. This study examined the influence of BC on pesticide chemical and biological accessibility using the herbicide isoproturon (IPU). Soils amended with 1% and 2% BC showed enhanced sorption, slower desorption, and reduced biodegradation of IPU. Addition of 0.1% BC had no effect on sorption, desorption or biodegradation of IPU. However, the mineralization of (14)C-IPU was reduced by all BC concentrations, reducing by 13.6%, 40.1% and 49.8% at BC concentrations of 0.1%, 1% and 2% respectively. Further, the ratio of the toxic metabolite 4-isopropyl-aniline to intact IPU was substantially reduced by higher BC concentrations. Hydroxypropyl-β-cyclodextrin (HPCD) extractions were used to estimate the IPU bioaccessibility in the BC-amended soil. Significant correlations were found between HPCD-extracted (14)C-IPU and the IPU desorbed (%) (r(2)=0.8518, p<0.01), and also the (14)C-IPU mineralized (%) (r(2)=0.733; p<0.01) for all BC-amended soils. This study clearly demonstrates how desorption in the presence of BC is intimately related to pesticide biodegradation by the indigenous soil microbiota. BC application to agricultural soils can affect the persistence of pesticides as well as the fate of their degradation products. This has important implications for the effectiveness of pesticides as well as the sequestration of contaminants in soils. Copyright © 2012 Elsevier Ltd. All rights reserved.

Ethoprophos fate on soil-water interface and effects on non-target terrestrial and aquatic biota under Mediterranean crop-based scenarios.

PubMed

Leitão, Sara; Moreira-Santos, Matilde; Van den Brink, Paul J; Ribeiro, Rui; José Cerejeira, M; Sousa, José Paulo

2014-05-01

The present study aimed to assess the environmental fate of the insecticide and nematicide ethoprophos in the soil-water interface following the pesticide application in simulated maize and potato crops under Mediterranean agricultural conditions, particularly of irrigation. Focus was given to the soil-water transfer pathways (leaching and runoff), to the pesticide transport in soil between pesticide application (crop row) and non-application areas (between crop rows), as well as to toxic effects of the various matrices on terrestrial and aquatic biota. A semi-field methodology mimicking a "worst-case" ethoprophos application (twice the recommended dosage for maize and potato crops: 100% concentration v/v) in agricultural field situations was used, in order to mimic a possible misuse by the farmer under realistic conditions. A rainfall was simulated under a slope of 20° for both crop-based scenarios. Soil and water samples were collected for the analysis of pesticide residues. Ecotoxicity of soil and aquatic samples was assessed by performing lethal and sublethal bioassays with organisms from different trophic levels: the collembolan Folsomia candida, the earthworm Eisenia andrei and the cladoceran Daphnia magna. Although the majority of ethoprophos sorbed to the soil application area, pesticide concentrations were detected in all water matrices illustrating pesticide transfer pathways of water contamination between environmental compartments. Leaching to groundwater proved to be an important transfer pathway of ethoprophos under both crop-based scenarios, as it resulted in high pesticide concentration in leachates from Maize (130µgL(-1)) and Potato (630µgL(-1)) crop scenarios, respectively. Ethoprophos application at the Potato crop scenario caused more toxic effects on terrestrial and aquatic biota than at the Maize scenario at the recommended dosage and lower concentrations. In both crop-based scenarios, ethoprophos moved with the irrigation water flow to the soil between the crop rows where no pesticide was applied, causing toxic effects on terrestrial organisms. The two simulated agricultural crop-based scenarios had the merit to illustrate the importance of transfer pathways of pesticides from soil to groundwater through leaching and from crop rows to the surrounding soil areas in a soil-water interface environment, which is representative for irrigated agricultural crops under Mediterranean conditions. Copyright © 2014 Elsevier Inc. All rights reserved.

Pesticides in soil and sediment of a dyke-protected area of the Red River Delta, Vietnam

NASA Astrophysics Data System (ADS)

Braun, Gianna; Bläsing, Melanie; Kruse, Jens; Amelung, Wulf; Renaud, Fabrice; Sebesvari, Zita

2017-04-01

Coastal regions are densely populated but at the same time represent important agricultural areas for food production of the growing world population. To sustain high agricultural yields, in monocultures such as permanent rice systems, pesticides are used in high quantity and frequency. While earlier studies monitored the fate of pesticides in paddy rice systems, the overall fate of these compounds is altered nowadays due to the construction of dykes, which are needed in many delta regions to protect them from high tides, storm surges and salt water intrusion such as in the Red River Delta. The dyke system regulates the discharge and water exchange inside the diked area including irrigation channels for the paddy rice production. Local authorities observed increasing pollution towards the sea (highest pollution close to the dykes) and hypothesized that the dyke system would prevent water exchange and thus lead to an accumulation of pollutants within the diked area. Hence, the purpose of this study was to investigate the effect of dykes on pesticide pollution patterns in coastal delta regions of the Red River Delta. The study was conducted in the district Giao Thuy of the Red River Delta, Vietnam. This area is surrounded by a sea and river dyke; both have several inlet and outlet gates to control the water level in the irrigation channels. We determined the pesticide pollution pattern in a diked agricultural area, as well as along salinity gradients in and outside the diked areas. Samples were taken from rice fields and sediments from irrigation channels inside the diked area as well from saline aquaculture fields located outside the dyke. Pesticide analysis was conducted by accelerated solvent extraction (ASE), followed up by the clean-up process described by Laabs et al. (2007) and analyses using gas chromatography coupled with a mass selective detector (MSD). Preliminary results suggest that out of the 26 analysed compounds chlorpyrifos, propiconazole and isoprothiolane occurred frequently in samples taken from rice fields. Pesticide concentrations were not higher in rice field closer to the dykes. Pesticide concentrations within paddy fields are likely driven by pesticide inputs on site. However, pattern in canal sediment samples is more likely de-coupled from on-site applications. Results will be discussed in relation to adaptation to increasing salinity intrusion in coastal areas.

FATE AND EFFECTS OF THE ENANTIOMERS OF CHIRAL ENVIRONMENTAL POLLUTANTS

EPA Science Inventory

Enantiomers, the mirror image isomers of chiral compounds, are known to be selective in their interaction with other chiral molecules, including enzymes and other biochemicals. This holds true for pesticides, about 25% of which are chiral molecules, and other chiral environmental...

40 CFR 158.2084 - Experimental use permit biochemical pesticides nontarget organisms and environmental fate data...

Code of Federal Regulations, 2010 CFR

2010-07-01

... acute freshwater invertebrate study. (2) The data in this section are not required for arthropod... invertebrate acute toxicity, freshwater R R NR R NR TGAI, EP 2, 4 (e) Test notes. The following test notes are...

Enantioselective Effects of Chiral Pesticides on their Primary Targets and Secondary Targets.

PubMed

Yang, Ye; Zhang, Jianyun; Yao, Yijun

2017-01-01

Enantioselectivity has been well recognized in the environmental fate and effects of chiral pesticides. Enantiospecific action of the optical enantiomers on the biological molecules establishes the mechanistic basis for the enantioselective toxicity of chiral pesticides to both target and non-target organisms. We undertook a structured search of bibliographic databases for research literature concerning the enantioselective effects of chiral pesticides, including insecticides, herbicides and fungicides, on biomolecules in various species by using some key words. The results of the relevant literatures were reviewed in the text and summarized in tables. Pesticides generally exert their activity on the target organisms via disrupting the primary target biomolecules. In non-target species, effects of pesticides on the secondary targets distinguished from the primary ones make great contribution to their toxicity. Recent investigations have provided convincing evidence of enantioselective toxicity of chiral pesticides to both target and non-target species which is recognized to result from their enantiospecific action on the primary or secondary targets in organisms. This review confirms that chiral pesticides have enantiospecific effects on both primary and secondary target biomolecules in organisms. Future studies regarding toxicological effects of chiral pesticides should focus on the relationship between the enantiomeric difference in the compound-biomolecules interaction and the enantioselectivity in their toxicity.

Interaction of pesticides with natural and synthetic solids. Evaluation in dynamic and equilibrium conditions.

PubMed

Otalvaro, Julián Ortiz; Brigante, Maximiliano

2018-03-01

Interactions between pesticides (paraquat, glyphosate, 2,4-D, atrazine, and metsulfuron methyl) and soil organic and inorganic components have been studied in batch experiments by performing adsorption, dissolution, and chemical and photochemical degradation under different conditions. The obtained results confirm that the affinity of a pesticide to the solid surface depends on the nature of both and shows that each reactant strongly affects the mobility of the other one, e.g., anionic pesticides promote the dissolution of the solid humic acid but if this last is retained into the inorganic matrix enhances the adsorption of a cationic pesticide. Adsorption also seems to protect the bonded specie to be chemical degraded, such as shown in two pesticide/clay systems at constant pH. The use of mesoporous silicas could result in a good alternative for pesticide remediation. In fact, the solid shows high adsorption capacity towards paraquat and its modification with TiO 2 nanoparticles increases not only the pesticide adsorption but also seems to catalyze its degradation under UV light to less-toxic metabolites. UV-VIS spectroscopy was relevant and novel in such sense. Electrostatic interactions, hydrogen and coordinative bonds formations, surface complexations and hydrophobic associations play a key role in the fate of mentioned pesticides on soil and ground/surface water environments.

Differences in fate, behavior and uptake of conventional- and nano-pesticides

NASA Astrophysics Data System (ADS)

Anuar, M. Firdaus Mohd; E Hodson, Mark; Boxall, Alistair BA

2017-04-01

Nanopesticides, in which conventional pesticides are designed into nanoparticles, are now available and are marketed as having improved longevity and efficacy in the environment. Nanoparticles are known to have different properties to dissolved chemicals and as such it is possible that the fate and behaviour of nanopesticides differs from conventional pesticides. We present work on the synthetic pyrethroid bifenthrin to explore the implications of nanoencapsulation for the sorption, persistence and uptake of the active ingredient in soil-earthworm systems. Studies were done using the active ingredient, a traditional formulation and two nanoformulations. In adsorption experiments conducted using five soils with a range of properties (pH 4.7 - 7.7; % organic carbon 1.2 - 5.2; texture silt loam to loamy sand), adsorption was well described by linear isotherms. Adsorption of analytical grade bifenthrin (Kd = 1800 - 7200 mL / g) was greater than that of a commercial formulation (Kd = 190 - 470 mL / g) which in turn was greater than that of nanoformulations (Kd = 52 - 150 mL / g). For all bifenthrin types adsorption increased with increasing soil organic matter content. Degradation rates of the analytical grade bifenthrin and commercial formulation were similar and faster than those of nanoformulations. Degradation rates were faster in non-sterile compared to sterile conditions. These results suggest that nano-encapsulation could lead to increased mobility and persistence of bifenthrin in the environment and therefore potentially increased exposure and bioavailability. To investigate the effects of nanoencapsulation on uptake we carried out a series of uptake and excretion experiments using the earthworms Eisenia fetida and Lumbricus terrestris. Over the exposure period the concentration of bifenthrin in the soil decreased and increased in the earthworms. Rates of accumulation and excretion were greater for the nanobifenthrin than the non-nanoformulation and active ingredient. Dissection and analysis of earthworm tissues indicated that the accumulated bifenthrin from the nano exposure was concentrated in the earthworm gut whereas the accumulated bifenthrin in the conventional exposure was concentrated in the earthworm tissues. We used kinetic modelling to determine bioconcentration factors. The higher accumulation and excretion rates result in predicted lower bioconcentration factors for the nanobofenthrin compared to the conventional and analytical grade forms. Our experiments demonstrate the differing behaviours of a conventional and nano-formluated pesticide therefore suggesting that current environmental risk assessment methodologies for conventional pesticides may not be appropriate for nanoformulations.

Leaching and sorption of neonicotinoid insecticides and fungicides from seed coatings

USGS Publications Warehouse

Smalling, Kelly; Hladik, Michelle; Sanders, Corey; Kuivila, Kathryn

2018-01-01

Seed coatings are a treatment used on a variety of crops to improve production and offer protection against pests and fungal outbreaks. The leaching of the active ingredients associated with the seed coatings and the sorption to soil was evaluated under laboratory conditions using commercially available corn and soybean seeds to study the fate and transport of these pesticides under controlled conditions. The active ingredients (AI) included one neonicotinoid insecticide (thiamethoxam) and five fungicides (azoxystrobin, fludioxonil, metalaxyl, sedaxane thiabendazole). An aqueous leaching experiment was conducted with treated corn and soybean seeds. Leaching potential was a function of solubility and seed type. The leaching of fludioxonil, was dependent on seed type with a shorter time to equilibrium on the corn compared to the soybean seeds. Sorption experiments with the treated seeds and a solution of the AIs were conducted using three different soil types. Sorption behavior was a function of soil organic matter as well as seed type. For most AIs, a negative relationship was observed between the aqueous concentration and the log Koc. Sorption to all soils tested was limited for the hydrophilic pesticides thiamethoxam and metalaxyl. However, partitioning for the more hydrophobic fungicides was dependent on both seed type and soil properties. The mobility of fludioxonil in the sorption experiment varied by seed type indicating that the adjuvants associated with the seed coating could potentially play a role in the environmental fate of fludioxonil. This is the first study to assess, under laboratory conditions, the fate of pesticides associated with seed coatings using commercially available treated seeds. This information can be used to understand how alterations in agricultural practices (e.g., increasing use of seed treatments) can impact the exposure (concentration and duration) and potential effects of these chemicals to aquatic and terrestrial organisms.

C, N, and H isotope fractionation of the herbicide isoproturon reflects different microbial transformation pathways.

PubMed

Penning, Holger; Sørensen, Sebastian R; Meyer, Armin H; Aamand, Jens; Elsner, Martin

2010-04-01

The fate of pesticides in the subsurface is of great interest to the public, industry, and regulatory authorities. Compound-specific isotope analysis (CSIA) is a promising tool complementary to existing methods for elucidating pesticide degradation reactions. Here, we address three different initial biotransformation reactions of the phenylurea herbicide isoproturon (3-(4-isopropylphenyl)-1,1-dimethylurea) in pure culture experiments with bacterial and fungal strains. When analyzing isotopic changes in different parts of the isoproturon molecule, hydroxylation of the isopropyl group by fungi was found to be associated with C and H isotope fractionation. In contrast, hydrolysis by Arthrobacter globiformis D47 caused strong C and N isotope fractionation, albeit in a different manner than abiotic hydrolysis so that isotope measurements can distinguish between both modes of transformation. No significant isotope fractionation was observed during N-demethylation by Sphingomonas sp. SRS2. The observed isotope fractionation patterns were in agreement with the type of reactions and elements involved. Moreover, their substantially different nature suggests that isotope changes in natural samples may be uniquely attributed to either pathway, allowing even to distinguish the abiotic versus biotic nature of hydrolysis. Our investigations show how characteristic isotope patterns may significantly add to the present understanding of the environmental fate of pesticides.

An investigation of oxidation products and SOA yields from OH + pesticide reactions

NASA Astrophysics Data System (ADS)

Murschell, T.; Friedman, B.; Link, M.; Farmer, D.

2016-12-01

Pesticides are used globally in agricultural and residential areas. After application and/or volatilization from a surface, these compounds can be transported over long distances in the atmosphere. However, their chemical fate, including oxidation and gas-particle partitioning in the atmosphere, is not well understood. We present gas and particle measurements of oxidation products from pesticide + OH reactions using a dynamic solution injection system coupled to an Oxidative Flow Reactor. Products were detected with a High Resolution Time of Flight Iodide Chemical Mass Spectrometer (HR-ToF-CIMS) and a Size Mobility Particle Scanner (SMPS). The OFR allows pesticides to react with variable OH radical exposures, ranging from the equivalent of one day to a full week of atmospheric oxidative aging. In this work, we explore pesticide oxidation products from reaction with OH and ozone, and compare those products to photolysis reactions. Pesticides of similar chemical structures were explored, including acetochlor / metolachlor and permethrin / cypermethrin, to explore mechanistic differences. We present chemical parameters including average product oxidation state, average oxygen to carbon ratio, and potential secondary organic aerosol formation for each of these compounds.

OBSERVATIONS OF ENANTIOSELECTIVITY IN THE FATE, PERSISTENCE AND EFFECTS OF MODERN PESTICIDES

EPA Science Inventory

Chiral pollutants exist as 2 (or more) species, -- enantiomers -- that are non-superimposable mirror images of each other. Enantiomers have identical physical and chemical properties except when they interact with enzymes or other chiral molecules; then they usually react select...

Analysis of Bioenergy Residues (biochar and digestate) to Study the Fate of Pesticides for Biopurification Systems

NASA Astrophysics Data System (ADS)

Mukherjee, S.

2015-12-01

To overcome the problem of on farm point sources of pollution, environmental friendly and low cost technology filter systems are under development. Processes like sorption-desorption, dissipation behavior of three radiolabeled pesticides (Bentazone, Boscalid and Pyrimethanil) has been investigated at lab scale. Biochar and digestate mixtures with two types of soil (sandy and silt loam) had been used as a biofilter test material for a respiration study (over three month's time period) instead of conventional soil, peat and straw mixtures. The results show that digestate is an easily available C-source leading to highest release of CO2-C. It was found that with the addition of even a small amount (1 % W/W) of biochar there is a profound suppression in the CO2-C release.The driving mechanism for this suppression can be manifold like negative priming, chemisorption of CO2-C on biochar or combinations of all. Further, the fate of applied organic contaminants to biomixtures depends on factors like soil properties as well as biological degradation by soil microbes. To analyze the degradation potential of the different soil/amendment mixtures on pesticides a degradation study was performed. The results from the 14C labelled pesticides study indicated that a mixture of digestate (5%) and biochar (5%) well balanced the mineralization (~20% for bentazone, ~6% for boscalid and ~2% for pyrimethanil) and sorption process (>85% non-extractable residues for all pesticides) resulting in favorable dissipation process. To investigate the sorption-desorption potential of the above pesticides a batch equilibrium study was carried out with selected biomixtures. A higher Kd (>1500 L kg-1), kf (>400 μM1-1/nf L1/nfkg-1) and KL (>40 L kg-1) was obtained for all pesticides for the soil/digestate/biochar mixtures, which had a higher organic matter content. SUVA254 values justified the aromatic character of digestate (5%) and biochar (5%) mixture which showed highest Koc values among all mixtures. This mixture found to be the most promising substrate amongst the tested ones for a biobed setup.

Fate and effect of imidacloprid on vermicompost-amended soils under dissimilar conditions: Risk for soil functions, structure, and bacterial abundance.

PubMed

Castillo Diaz, Jean Manuel; Martin-Laurent, Fabrice; Beguet, Jérèmie; Nogales, Rogelio; Romero, Esperanza

2017-02-01

The fate and impact of pesticide on soil depend partly on the agricultural practices, such as prior treatment with pesticide and/or organic amendments. As a means of determining how the previous soil conditions can affect the fate of imidacloprid (IMI) and its effect on soil functions, experiments were made with soil samples, double-amended or not with either vine-shoot (W) or olive cake (O) vermicompost or contaminated or not with IMI. These soil samples, incubated for 3months, were placed in two microcosms (M1 with the pre-amended soils and M2 with the pre-exposed soils), treated with IMI and amended with vermicomposts and then incubated for 3months. The IMI distribution on soil fractions, sorption processes, dissipation kinetics, and biochemical as well as genetic structure and bacterial abundance were determined to assess the fate and impact of IMI on the soil. The addition of W vermicompost to the soil reduced the IMI availability. The dissipation kinetic in soils from M1 and M2 followed, respectively, a single first-order and a double first-order in parallel models. The lowest IMI persistence corresponded to the soil from M2 amended with O-vermicompost with DT50 and DT90 values of 67d and 265d, while in the other soils 90% dissipation required >512d. The vermicomposts-amended contaminated soils increased the dehydrogenase activity by 2- and 4-fold respect the control soils. However, the urease activity decreased due to the IMI influence. The changes in the bacterial community in the contaminated soil amended with O-vermicompost during incubation were correlated with the dissipation rate constant of IMI, suggesting a better tolerance of microorganisms to IMI. Thus, in the soil contaminated with IMI, the amendment with the vermicompost from olive cake can mitigate the impact of this insecticide on soil functions and promote its depuration capability while minimizing environmental risks. Copyright © 2016 Elsevier B.V. All rights reserved.

The exposure of honey bees (Apis mellifera; Hymenoptera: Apidae) to pesticides: Room for improvement in research.

PubMed

Benuszak, Johanna; Laurent, Marion; Chauzat, Marie-Pierre

2017-06-01

Losses of honey bees have been repeatedly reported from many places worldwide. The widespread use of synthetic pesticides has led to concerns regarding their environmental fate and their effects on pollinators. Based on a standardised review, we report the use of a wide variety of honey bee matrices and sampling methods in the scientific papers studying pesticide exposure. Matrices such as beeswax and beebread were very little analysed despite their capacities for long-term pesticide storage. Moreover, bioavailability and transfer between in-hive matrices were poorly understood and explored. Many pesticides were studied but interactions between molecules or with other stressors were lacking. Sampling methods, targeted matrices and units of measure should have been, to some extent, standardised between publications to ease comparison and cross checking. Data on honey bee exposure to pesticides would have also benefit from the use of commercial formulations in experiments instead of active ingredients, with a special assessment of co-formulants (quantitative exposure and effects). Finally, the air matrix within the colony must be explored in order to complete current knowledge on honey bee pesticide exposure. Copyright © 2017 Elsevier B.V. All rights reserved.

Method of analysis and quality-assurance practices for determination of pesticides in water by solid-phase extraction and capillary-column gas chromatography/mass spectrometry at the U.S. Geological Survey California District Organic Chemistry Laboratory, 1996-99

USGS Publications Warehouse

Crepeau, Kathryn L.; Baker, Lucian M.; Kuivila, Kathryn

2000-01-01

A method of analysis and quality-assurance practices were developed to study the fate and transport of pesticides in the San Francisco Bay-Estuary by the U.S. Geological Survey. Water samples were filtered to remove suspended-particulate matter and pumped through C-8 solid-phase extraction cartridges to extract the pesticides. The cartridges were dried with carbon dioxide and the pesticides were eluted with three cartridge volumes of hexane:diethyl ether (1:1) solution. The eluants were analyzed using capillary-column gas chromatography/mass spectrometry in full-scan mode. Method detection limits for pesticides ranged from 0.002 to 0.025 microgram per liter for 1-liter samples. Recoveries ranged from 44 to 140 percent for 25 pesticides in samples of organic-free reagent water and Sacramento-San Joaquin Delta and Suisun Bay water fortified at 0.05 and 0.50 microgram per liter. The estimated holding time for pesticides after extraction on C-8 solid-phase extraction cartridges ranged from 10 to 257 days.

Measurement of the exposure of workers to pesticides*

PubMed Central

Durham, William F.; Wolfe, Homer R.

1962-01-01

There is not a single pesticide for which the interrelationships between occupational exposure by different routes, the fate of the compound in the human body, and its clinical effects are all adequately known. Results of the direct measurement of exposure to pesticides may be used in evaluating the relative hazard of different routes of exposure, different operational procedures, and different protective devices. Results of the indirect measurement of exposure may be of use for the same purpose; in addition, these indirect measures may be used in relating exposures under observed conditions to clinical effects. This paper describes and evaluates detailed procedures for the use of air samples, pads, and washes in the direct measurement of the dermal and respiratory exposure of workers to pesticides. Good methods are not available for measuring oral exposure. Any measure of the absorption, storage, physiological effect, or excretion of a compound constitutes an indirect indication of exposure to it. ImagesFIG. 2 PMID:13888659

Sorption and degradation of neonicotinoid insecticides in tropical soils.

PubMed

Dankyi, Enock; Gordon, Chris; Carboo, Derick; Apalangya, Vitus A; Fomsgaard, Inge S

2018-05-22

Neonicotinoids are the most widely applied class of insecticides in cocoa farming in Ghana. Despite the intensive application of these insecticides, knowledge of their fate in the Ghanaian and sub-Saharan African environment remains low. This study examined the behavior of neonicotinoids in soils from cocoa plantations in Ghana by estimating their sorption and degradation using established kinetic models and isotherms. Studies of sorption were conducted using the batch equilibrium method on imidacloprid, thiamethoxam, clothianidin, acetamiprid and thiacloprid, while degradation of imidacloprid, thiamethoxam and their respective deuterated counterparts was studied using models proposed by the European forum for coordination of pesticide fate and their use (FOCUS). Analytes were extracted using the quick, easy, cheap, effective, rugged and safe (QuEChERS) procedure and quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Average recoveries were high (≥ 85%) for all analytes. The findings from the study suggest that neonicotinoid insecticides may be persistent in the soils studied based on estimated half-lives > 150 days. The study also revealed generally low-sorption coefficients for neonicotinoids in soils, largely influenced by soil organic carbon.

Combination of a higher-tier flow-through system and population modeling to assess the effects of time-variable exposure of isoproturon on the green algae Desmodesmus subspicatus and Pseudokirchneriella subcapitata.

PubMed

Weber, Denis; Schaefer, Dieter; Dorgerloh, Michael; Bruns, Eric; Goerlitz, Gerhard; Hammel, Klaus; Preuss, Thomas G; Ratte, Hans Toni

2012-04-01

A flow-through system was developed to investigate the effects of time-variable exposure of pesticides on algae. A recently developed algae population model was used for simulations supported and verified by laboratory experiments. Flow-through studies with Desmodesmus subspicatus and Pseudokirchneriella subcapitata under time-variable exposure to isoproturon were performed, in which the exposure patterns were based on the results of FOrum for Co-ordination of pesticide fate models and their USe (FOCUS) model calculations for typical exposure situations via runoff or drain flow. Different types of pulsed exposure events were realized, including a whole range of repeated pulsed and steep peaks as well as periods of constant exposure. Both species recovered quickly in terms of growth from short-term exposure and according to substance dissipation from the system. Even at a peak 10 times the maximum predicted environmental concentration of isoproturon, only transient effects occurred on algae populations. No modified sensitivity or reduced growth was observed after repeated exposure. Model predictions of algal growth in the flow-through tests agreed well with the experimental data. The experimental boundary conditions and the physiological properties of the algae were used as the only model input. No calibration or parameter fitting was necessary. The combination of the flow-through experiments with the algae population model was revealed to be a powerful tool for the assessment of pulsed exposure on algae. It allowed investigating the growth reduction and recovery potential of algae after complex exposure, which is not possible with standard laboratory experiments alone. The results of the combined approach confirm the beneficial use of population models as supporting tools in higher-tier risk assessments of pesticides. Copyright © 2012 SETAC.

BIOACCUMULATION AND BIOTRANSFORMATION OF CHIRAL TRIAZOLE FUNGICIDES IN RAINBOW TROUT (ONCORHYNCHUS MYKISS)

EPA Science Inventory

There are very little data on the bioaccumulation and biotransformation of current-use pesticides (CUPs) despite the fact that such data are critical in assessing their fate and potential toxic effects in aquatic organisms. To help address this issue, juvenile rainbow trout (Onco...

The next generation of pesticides

USDA-ARS?s Scientific Manuscript database

Every year, the fate of the entomological world is discussed by 2,000-3,000 entomologists at the annual meeting of the Entomological Society of America (this year held in Knoxville, TN). Often, a hot topic is clearly identifiable from this meeting. This year is no exception: the major theme of the m...

Examining the fate and transport of alpha- and beta-endosulfan in the atmosphere of South Florida

USDA-ARS?s Scientific Manuscript database

Agricultural activity in the South Florida region occurs in close proximity to both important natural areas like Biscayne and Everglades National Parks. One possible transport mechanism for pesticides into these sensitive ecosystems is release to the atmosphere after application. The process is en...

FATE AND BIOAVAILABILITY OF ARSENIC IN ORGANO-ARSENICAL PESTICIDE APPLIED SOILS. PART-I. INCUBATION STUDY. (R830842)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Environmental and human risk hierarchy of pesticides: A prioritization method, based on monitoring, hazard assessment and environmental fate.

PubMed

Tsaboula, Aggeliki; Papadakis, Emmanouil-Nikolaos; Vryzas, Zisis; Kotopoulou, Athina; Kintzikoglou, Katerina; Papadopoulou-Mourkidou, Euphemia

2016-05-01

A pesticide prioritization approach was developed and implemented in the Pinios River Basin of Central Greece. It takes under consideration the Level of Environmental Risk containing information on the frequency of occurrence of pesticides above environmental thresholds, the intensity of this occurrence and the spatial distribution as well as information about the fate and behavior of pesticides in the environment and the potential to have adverse impact on humans' health. Original 3-year monitoring data from 102 Stationary Sampling Sites located on rivers and their tributaries, reservoirs, streams and irrigation/drainage canals giving rise to a collection of 2382 water samples resulting in 7088 data sets, were included in this integrated prioritization study. Among 302 monitored active ingredients, 119 were detected at least once and the concentrations found in the aquatic systems for 41% of compounds were higher than the respective lowest Predicted Non-Effect Concentration (PNEC) values. Sixteen and 5 pesticides were found with risk ratios (MECmax/PNEC) above 10 (high concern) and 100 (very high concern), respectively. However, pesticides with maximum Measured Environmental Concentration (MECmax) values exceeding by 1000 times the respective lowest PNEC values were also found which were considered of extremely high concern; in the latter group were included prometryn, chlorpyrifos, diazinon, λ-cyhalothrin, cypermethrin, α-cypermethrin deltamethrin, ethalfluralin and phosmet. The sensitivity of the analytical methods used in the monitoring study was considered inadequate to meet the toxicological endpoints for 32 pesticides. The widest distribution of occurrence in the Stationary Sampling Sites of the monitoring program was found for the pesticides, prometryn, fluometuron, terbuthylazine, S-metolachlor, chlorpyrifos, diphenylamine, acetochlor, alachlor, 2,4-D, etridiazole, imidacloprid and lindane (γ-ΗCH). Among the 27 priority pesticides included in the Directive 2013/39/EU, in the present study 13 pesticides were considered as candidates for River Basin Specific Pollutants (RBSP) for the River Basin of Pinios. Among the 30 pesticide specific pollutants that were established by the Greek authorities, in the present study only 6 were considered as candidates for RBSP for the river basin of Pinios. As a result of the implementation of the prioritization approach developed in this study a total of 71 pesticides were identified as being RBSP for the river basin of Pinios. The higher Level of Environmental Risk was found to be exerted by the organophosphorus insecticide chlorpyrifos, followed by lindane and prometryn. The present study provides background information for important decisions to be made concerning the selection of pesticides which should be included in the target analyte list of new monitoring and screening programs of surface water quality in the Pinios River Basin. In addition, the prioritization approach proposed here can be useful for the development of River Basin Management Plans. Copyright © 2016 Elsevier Ltd. All rights reserved.

Clustering pesticides according to their molecular properties and their impacts by considering additional ecotoxicological parameters in the TyPol method

NASA Astrophysics Data System (ADS)

Traore, Harouna; Crouzet, Olivier; Mamy, Laure; Sireyjol, Christine; Rossard, Virginie; Servien, Remy; Latrille, Eric; Benoit, Pierre

2017-04-01

The understanding of the fate of pesticides and their environmental impacts largely relies on their molecular properties. We recently developed 'TyPol' (Typology of Pollutants), a clustering method based on statistical analyses combining several environmental endpoints (i.e. environmental parameters such as sorption coefficient, degradation half-life) and one ecotoxicological one (bioconcentration factor), and structural molecular descriptors (number of atoms in the molecule, molecular surface, dipole moment, energy of orbitals…). TyPol has been conceived on the available knowledge on QSAR of a wide diversity of organic compounds (Mamy et al., 2015). This approach also allows to focus on transformation products present in different clusters and to infer possible changes in environmental fate consecutively to different degradation processes (Servien et al., 2014; Benoit et al., 2016). The initial version of TyPol did not include any ecotoxicological parameters except the bioconcentration factor (BCF), which informs more on the transfer along the trophic chain rather than on the effects on non-target organisms. The objective was to implement the TyPol database with a data set of ecotoxicological data concerning pesticides and several aquatic and terrestrial organisms, in order to test the possibility to extend TyPol to ecotoxicological effects on various organisms. The data analysis (available literature and databases) revealed that relevant ecotoxicological endpoints for terrestrial organisms such as soil microorganisms and macroinvertebrates are lacking compared to aquatic organisms. We have added seven parameters for acute (EC50, LC50) and chronic (NOEC) toxicological effects for the following organisms: Daphnia, Algae, Lemna and Earthworm. In this new configuration, TyPol was used to classify about 45 pesticides in different behavioural and ecotoxicity clusters. The clustering results were analyzed to reveals relationships between molecular descriptors, environmental parameters and the added toxicological parameters. Some trends between soil adsorption or Kow coefficient and the acute toxicity towards earthworms or algae were highlighted, and discussed on the basis of the concept of contaminant bioavailability. This proof-of-concept study also showed that the in silico clustering method TyPol can successfully address new questions and can be expanded with other parameters of interest. Keywords: pesticides, toxicity, QSAR, clustering, PLS References : Servien R., Mamy L., Li Z., Rossard V., Latrille E., Bessac F., Patureau D., Benoit P., 2014. TyPol - A new methodology for organic compounds clustering based on their molecular characteristics and environmental behavior. Chemosphere, 111, 613-622. Mamy L., Patureau D., Barriuso E., Bedos C., Bessac F., Louchart X., Martin-Laurent F., Miege C., Benoit P., 2015. Prediction of the fate of organic compounds in the environment from their molecular properties: A review. Critical Reviews in Environmental Science and Technology, 45, 12, 1277-1377 (Open access). Benoit P., Mamy L., Servien R., Li Z., Latrille E., Rossard V., Bessac F., Patureau D., Martin-Laurent F. 2017. Categorizing chlordecone potential degradation products to explore their environmental fate. Science of the Total Environment, 574, 781-795.

Sediment-associated pesticides in an urban stream in Guangzhou, China: implication of a shift in pesticide use patterns.

PubMed

Li, Huizhen; Sun, Baoquan; Lydy, Michael J; You, Jing

2013-04-01

Pesticide use patterns in China have changed in recent years; however, the study of the environmental fate of current-use pesticides (CUPs) and their ecotoxicological significance in aquatic ecosystems is limited. In the present study, sediments were collected from an urban stream in the Chinese city of Guangzhou. Sediment-associated legacy organochlorine pesticides and CUPs-including organophosphates, pyrethroids, fipronil, and abamectin-were analyzed. Additionally, the relative toxicity of the sediments was evaluated with 10-d bioassays using Chironomus dilutus. Fifteen of 16 sediments collected from the stream were acutely toxic to C. dilutus, with 81% of the samples causing 100% mortality. Abamectin, fipronil, and pyrethroids (mainly cypermethrin) were identified as the principal contributors to the noted toxicity in the midges, with median predicted toxic units of 1.63, 1.63, and 1.03, respectively. Sediments taken from downstream sites, where residential and industrial regions were located, had elevated CUP concentrations and sediment toxicity compared with upstream sites. The present study is the first of its kind to link sediment CUPs, fipronil, and abamectin concentrations with toxicity in urban streams in China with a focus on shifting pesticide usage patterns. Copyright © 2013 SETAC.

An assessment of environmental and toxicological risk to pesticide exposure based on a case-based approach to computing

NASA Astrophysics Data System (ADS)

Coelho, Cristina; Vicente, Henrique; Rosário Martins, M.; Lima, Nelson; Neves, Mariana; Neves, José

2017-01-01

Pesticide environmental fate and toxicity depends on its physical and chemical features, the soil composition, soil adsorption, as well as residues that may be found in different soil slots. Indeed, pesticide degradation in soil may be influenced by either biotic or abiotic factors. In addition, the toxicity of pesticides for living organisms depends on their adsorption, distribution, biotransformation, dissemination of metabolites together with interaction with cellular macromolecules and excretion. Biotransformation may result in the formation of less toxic and/or more toxic metabolites, while other processes determine the balance between toxic and a nontoxic upcoming. Aggregate exposure and risk assessment involve multiple pathways and routes, including the potential for pesticide residues in food and drinking water, in addition to residues from pesticide use in residential and non-occupational environments. Therefore, this work will focus on the development of a decision support system to assess the environmental and toxicological risk to pesticide exposure, built on top of a Logic Programming approach to Knowledge Representation and Reasoning, complemented with a Case Based attitude to computing. The proposed solution is unique in itself, once it caters for the explicit treatment of incomplete, unknown, or even self-contradictory information, either in terms of a qualitative or quantitative setting.

Evaluating the potential of 'on-line' constructed wetlands for mitigating pesticide transfers from agricultural land to surface waters

NASA Astrophysics Data System (ADS)

Whelan, Michael; Ramos, Andre; Guymer, Ian; Villa, Raffaella; Jefferson, Bruce

2016-04-01

Pesticides make important contributions to modern agriculture but losses from land to water can present problems for environmental management, particularly in catchments where surface waters are abstracted for drinking water. Where artificial field drains represent a dominant pathway for pesticide transfers, buffer zones provide little mitigation potential. Instead, "on-line" constructed wetlands have been proposed as a potential means of reducing pesticide fluxes in drainage ditches and headwater streams. Here, we evaluate the potential of small free-surface wetlands to reduce pesticide concentrations in surface waters using a combination of field monitoring and numerical modelling. Two small constructed wetland systems in a first order catchment in Cambridgeshire, UK, were monitored over the 2014-2015 winter season. Discharge was measured at several flow control structures and samples were collected every eight hours and analysed for metaldehyde, a commonly-used molluscicide. Metaldehyde is moderately mobile and, like many other compounds, it has been regularly detected at high concentrations in surface water samples in a number of drinking water supply catchments in the UK over the past few years. However, it is unusually difficult to remove via conventional drinking water treatment which makes it particularly problematical for water companies. Metaldehyde losses from the upstream catchment were significant with peak concentrations occurring in the first storm events in early autumn, soon after application. Concentrations and loads appeared to be unaffected by transit through the wetland over a range of flow conditions - probably due to short solute residence times (quantified via several tracing experiments employing rhodamine WT - a fluorescent dye). A dynamic model, based on fugacity concepts, was constructed to describe chemical fate in the wetland system. The model was used to evaluate mitigation potential and management options under field conditions and for a range of different pesticides under alternative flow and wetland dimension scenarios. In agreement with observations, model predictions for metaldehyde losses in the monitored system were negligible. The scenario analysis suggested that, even for pesticides with a relatively short aquatic half life, wetland systems would need to be much larger than those studied here in order to get any appreciable attenuation. Shallow systems have highest potential for promoting losses due to biodegradation, if we assume that most degrading organisms reside in fixed biofilms in the sediment. Sorption is not predicted to represent a significant net sink, except over short time scales in the first runoff event after application.

Long-term relationships among pesticide applications, mobility, and soil erosion in a vineyard watershed

NASA Astrophysics Data System (ADS)

Sabatier, Pierre; Poulenard, Jérôme; Fanget, Bernard; Reyss, Jean-Louis; Develle, Anne-Lise; Wilhelm, Bruno; Ployon, Estelle; Pignol, Cécile; Naffrechoux, Emmanuel; Dorioz, Jean-Marcel; Montuelle, Bernard; Arnaud, Fabien

2014-11-01

Agricultural pesticide use has increased worldwide during the last several decades, but the long-term fate, storage, and transfer dynamics of pesticides in a changing environment are poorly understood. Many pesticides have been progressively banned, but in numerous cases, these molecules are stable and may persist in soils, sediments, and ice. Many studies have addressed the question of their possible remobilization as a result of global change. In this article, we present a retro-observation approach based on lake sediment records to monitor micropollutants and to evaluate the long-term succession and diffuse transfer of herbicides, fungicides, and insecticide treatments in a vineyard catchment in France. The sediment allows for a reliable reconstruction of past pesticide use through time, validated by the historical introduction, use, and banning of these organic and inorganic pesticides in local vineyards. Our results also revealed how changes in these practices affect storage conditions and, consequently, the pesticides' transfer dynamics. For example, the use of postemergence herbicides (glyphosate), which induce an increase in soil erosion, led to a release of a banned remnant pesticide (dichlorodiphenyltrichloroethane, DDT), which had been previously stored in vineyard soil, back into the environment. Management strategies of ecotoxicological risk would be well served by recognition of the diversity of compounds stored in various environmental sinks, such as agriculture soil, and their capability to become sources when environmental conditions change.

Comparative toxicity of two azadirachtin-based neem pesticides to Daphnia pulex.

PubMed

Goktepe, Ipek; Plhak, Leslie C

2002-01-01

Azadirachtin (AZA)-based pesticides (Neemix and Bioneem) demonstrated toxicity in 48-h nonrenewal toxicity assays using Daphnia pulex at levels that were comparable with several organophosphate pesticides. The median lethal concentration (LC50) values for the two neem pesticides were found to be 0.028 and 0.033 microl/ml, respectively. The LC50 value for nonformulated (95% pure) AZA was determined to be 0.382 microg AZA/ml. Neemix and Bioneem were exposed to air and northern sky daylight in a light box at 24 and 37 degrees C for 1, 3, 6, and 9 d. Standard 48-h acute toxicity tests were used to determine the effect of aging in these dry environmental conditions. Neemix and Bioneem were also fractionated into volatile and nonvolatile fractions, and the toxicity of each was tested. Compared with Neemix, Bioneem remained toxic longer when exposed to light and air at 37 degrees C, indicating that this pesticide may be less prone to environmental degradation. When fractionated, the nonvolatile fractions for both pesticides exhibited significantly lower LC50 values than the full formulations. These results suggest that, depending on the application rate and environmental fate, AZA-based pesticides may have direct adverse effects on aquatic organisms and that the toxicity and stability of formulated pesticides depend on factors other than only the AZA concentration.

The mode of bioturbation triggers pesticide remobilization from aquatic sediments.

PubMed

Bundschuh, Mirco; Schletz, Marco; Goedkoop, Willem

2016-08-01

After their release into the aquatic environment, contaminants may - depending on the physicochemical properties - adsorb to sediments. From there these contaminants can either be buried or remobilised by abiotic factors (e.g., resuspension) as well as by the bioturbating activity of sediment dwelling invertebrates. Little is, however, know about the effects of bioturbation on the fate of pesticides. Therefore, the present study quantified the impact of the bioturbation mode of benthic invertebrate species (bio-diffusor vs. bio-irrigation), the invertebrate density (i.e. 0-8 individuals per replicate), and the substance-inherent properties (i.e. hydrophobicity, water solubility) on the remobilization of sediment-associated pesticides in a laboratory-based set-up over 13 days. We found that both the bioturbation mode (i.e., species identity) and species density, as well as pesticide properties (i.e., hydrophobicity) affected the direction and magnitude of remobilisation of sediment-bound pesticides. The oligochaeta Lumbriculus variegatus showed a density-dependent effect on the remobilization of lindane to the water phase, whereas those with the amphipod Monoporeia affinis and larvae of the midge Chironomus riparius did not. Although these findings show that sediments not per definition are a sink for pesticides, the rates of pesticide remobilization are limited. This observation, thus, suggests that the risk for aquatic communities posed by the remobilization of pesticides from the sediment due to bioturbation is low. Copyright © 2016. Published by Elsevier Inc.

Long-term relationships among pesticide applications, mobility, and soil erosion in a vineyard watershed

PubMed Central

Sabatier, Pierre; Poulenard, Jérôme; Fanget, Bernard; Reyss, Jean-Louis; Develle, Anne-Lise; Wilhelm, Bruno; Ployon, Estelle; Pignol, Cécile; Naffrechoux, Emmanuel; Dorioz, Jean-Marcel; Montuelle, Bernard; Arnaud, Fabien

2014-01-01

Agricultural pesticide use has increased worldwide during the last several decades, but the long-term fate, storage, and transfer dynamics of pesticides in a changing environment are poorly understood. Many pesticides have been progressively banned, but in numerous cases, these molecules are stable and may persist in soils, sediments, and ice. Many studies have addressed the question of their possible remobilization as a result of global change. In this article, we present a retro-observation approach based on lake sediment records to monitor micropollutants and to evaluate the long-term succession and diffuse transfer of herbicides, fungicides, and insecticide treatments in a vineyard catchment in France. The sediment allows for a reliable reconstruction of past pesticide use through time, validated by the historical introduction, use, and banning of these organic and inorganic pesticides in local vineyards. Our results also revealed how changes in these practices affect storage conditions and, consequently, the pesticides' transfer dynamics. For example, the use of postemergence herbicides (glyphosate), which induce an increase in soil erosion, led to a release of a banned remnant pesticide (dichlorodiphenyltrichloroethane, DDT), which had been previously stored in vineyard soil, back into the environment. Management strategies of ecotoxicological risk would be well served by recognition of the diversity of compounds stored in various environmental sinks, such as agriculture soil, and their capability to become sources when environmental conditions change. PMID:25313074

Long-term relationships among pesticide applications, mobility, and soil erosion in a vineyard watershed.

PubMed

Sabatier, Pierre; Poulenard, Jérôme; Fanget, Bernard; Reyss, Jean-Louis; Develle, Anne-Lise; Wilhelm, Bruno; Ployon, Estelle; Pignol, Cécile; Naffrechoux, Emmanuel; Dorioz, Jean-Marcel; Montuelle, Bernard; Arnaud, Fabien

2014-11-04

Agricultural pesticide use has increased worldwide during the last several decades, but the long-term fate, storage, and transfer dynamics of pesticides in a changing environment are poorly understood. Many pesticides have been progressively banned, but in numerous cases, these molecules are stable and may persist in soils, sediments, and ice. Many studies have addressed the question of their possible remobilization as a result of global change. In this article, we present a retro-observation approach based on lake sediment records to monitor micropollutants and to evaluate the long-term succession and diffuse transfer of herbicides, fungicides, and insecticide treatments in a vineyard catchment in France. The sediment allows for a reliable reconstruction of past pesticide use through time, validated by the historical introduction, use, and banning of these organic and inorganic pesticides in local vineyards. Our results also revealed how changes in these practices affect storage conditions and, consequently, the pesticides' transfer dynamics. For example, the use of postemergence herbicides (glyphosate), which induce an increase in soil erosion, led to a release of a banned remnant pesticide (dichlorodiphenyltrichloroethane, DDT), which had been previously stored in vineyard soil, back into the environment. Management strategies of ecotoxicological risk would be well served by recognition of the diversity of compounds stored in various environmental sinks, such as agriculture soil, and their capability to become sources when environmental conditions change.

Dual isotope plots reflect transformation pathways of pesticides: Potential to assess pesticide fate and elucidate transformation mechanisms

NASA Astrophysics Data System (ADS)

Meyer, Armin; Penning, Holger; Sorensen, Sebastian; Aamand, Jens; Elsner, Martin

2010-05-01

The degradation of pesticides in deeper soil layers and groundwater is of growing interest, because they have repeatedly been found in drinking water supply wells and may pose a risk to future water resources. Current assessment schemes face a common problem, however: natural degradation often cannot be reliably assessed by concentration measurements alone, since mass balances are difficult to establish and transformation cannot be distinguished from sorption or dilution. Even detection of metabolites may only give an incomplete picture. When several transformation pathways occur, some metabolites may be degraded or form bound residues so that the associated pathways may be missed. Our research shows that dual isotope plots derived from compound specific isotope analysis offer a novel approach to give additional, complementary insight into the natural degradation of pesticides. Detection of metabolites is not required, since the isotope fractionation can be fully observed in the pesticide itself. Specifically, different initial biotransformation reactions of the phenylurea herbicide isoproturon (3-(4-isopropylphenyl)-1,1-dimethylurea) in pure culture experiments with bacterial and fungal strains showed strongly pathway-dependent isotope fractionation. When analyzing isotopic changes in different parts of the isoproturon molecule, hydroxylation of the isopropyl group by fungi was found to be associated with C and H isotope fractionation. In contrast, hydrolysis by Arthrobacter globiformis D47 caused strong C and N isotope fractionation, albeit in a different manner than abiotic hydrolysis so that isotope measurements can distinguish between both modes of transformation. Likewise, we observed highly pathway-dependent C and N isotope fractionation of atrazine (1-chloro-3-ethylamino-5-isopropylamino-2,4,6-triazine). Desalkylation of atrazine by Rhodococcus sp. strain NI86/21 resulted in enrichment of both 13-C and 15-N in atrazine, whereas hydrolysis to hydroxyatrazine by Chelatobacter heintzii, Pseudomonas sp. ADP and Arthrobacter aurescens TC1 gave enrichment of 13-C, but depletion of 15-N. Comparison with abiotic reference experiments provided novel insight into the underlying enzymatic transformation mechanisms. Our investigations show how characteristic isotope patterns may significantly add to the present understanding of the environmental fate of pesticides.

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

Code of Federal Regulations, 2014 CFR

2014-07-01

... product. Notes that apply to an individual test including specific conditions, qualifications, or exceptions to the designated test are listed in paragraph (e) of this section. (b) Use patterns. Aquatic uses... ingredient; All=All of the above. Specific conditions, qualifications, or exceptions to the designated test...

A COMPUTATIONAL CHEMISTRY STUDY OF THE ENVIRONMENTALLY IMPORTANT ACID-CATALYZED HYDROLYSIS OF ATRAZINE AND RELATED 2-CHLORO-S-TRIAZINES

EPA Science Inventory

Many chlorine-containing pesticides, for example 2-chloro-s-triazines, are of great concern both environmentally and toxicologically. As a result, ascertaining or predicting the fate and transport of these compounds in soils and water is of current interest. Transformation pathwa...

The Plant as Metaorganism and Research on Next-Generation Systemic Pesticides – Prospects and Challenges

PubMed Central

Vryzas, Zisis

2016-01-01

Systemic pesticides (SPs) are usually recommended for soil treatments and as seed coating agents and are taken up from the soil by involving various plant-mediated processes, physiological, and morphological attributes of the root systems. Microscopic insights and next-generation sequencing combined with bioinformatics allow us now to identify new functions and interactions of plant-associated bacteria and perceive plants as meta-organisms. Host symbiotic, rhizo-epiphytic, endophytic microorganisms and their functions on plants have not been studied yet in accordance with uptake, tanslocation and action of pesticides. Root tips exudates mediated by rhizobacteria could modify the uptake of specific pesticides while bacterial ligands and enzymes can affect metabolism and fate of pesticide within plant. Over expression of specific proteins in cell membrane can also modify pesticide influx in roots. Moreover, proteins and other membrane compartments are usually involved in pesticide modes of action and resistance development. In this article it is discussed what is known of the physiological attributes including apoplastic, symplastic, and trans-membrane transport of SPs in accordance with the intercommunication dictated by plant–microbe, cell to cell and intracellular signaling. Prospects and challenges for uptake, translocation, storage, exudation, metabolism, and action of SPs are given through the prism of new insights of plant microbiome. Interactions of soil applied pesticides with physiological processes, plant root exudates and plant microbiome are summarized to scrutinize challenges for the next-generation pesticides. PMID:28018306

Partitioning of the pesticide trifluralin between dissolved organic matter and water using automated SPME-GC/MS.

PubMed

Caupos, Emilie; Touffet, Arnaud; Mazellier, Patrick; Croue, Jean-Philippe

2015-03-01

Solid-phase microextraction (SPME) was used to determine the equilibrium association constant for a pesticide, trifluralin (TFR), with dissolved organic matter (DOM). After optimization of the SPME method for the analysis of TFR, partition coefficients (K DOM) with three different sources of DOM were determined in buffered solutions at pH 7. Commercial humic acids and DOM fractions isolated from two surface waters were used. The values of log K DOM varied from 4.3 to 5.8, depending on the nature of the organic material. A good correlation was established between log K DOM and DOM properties (as measured with the H/O atomic ratio and UV absorbance), in agreement with literature data. This is consistent with the effect of polarity and aromaticity for governing DOM-pollutant associations, regardless of the origin of DOM. This association phenomenon is relevant to better understand the behavior of pesticides in the environment since it controls part of pesticide leaching and fate in aquatic systems.

Sustainable use of veterinary pharmaceuticals on the territory (Sust-PHarm): Linking available database of manure management and environmental fate models.

PubMed

Di Guardo, Andrea; Finizio, Antonio

2017-01-01

Analogously to the evolution of the EU legislation on pesticides, there is an increasing need of strategies aiming to reach a "sustainable use of veterinary pharmaceuticals". To this end, it is essential to develop tools, such as supporting information systems (SIS), for managing the environmental risks of veterinary pharmaceuticals on a territorial scale. In this context, we propose Sust-PHarm (SUSTainable use of veterinary Pharmaceuticals), a SIS useful to identify groundwater vulnerable areas to veterinary pharmaceuticals at both local and regional scale. As background, Sust-PHarm follows the schemes of SIS for pesticides. The latter are based on the integration of predictive models in GIS. The proposed approach goes a step forward by integrating also data on the typologies of livestock farm, their spatial distribution and manure management techniques. This information allows to identify the potential environmental loads of veterinary pharmaceuticals. In this paper, we discuss the innovative elements characterizing Sust-PHarm through a comparison with the SIS currently used for pesticides. The advantages of Sust-PHarm are discussed using Lombardia Region (Northern Italy) as a case study. Simulations were made on 12 veterinary pharmaceuticals characterized by different physical-chemical properties. Results are compared with the current guidelines for the evaluation of veterinary pharmaceuticals leaching highlighting some substantial differences when realistic data are utilized making our approach more accurate than guidelines one. Copyright © 2016 Elsevier B.V. All rights reserved.

When synthetic chemicals degrade in the environment: What are the absolute fate, effects, and potential risks to humans and the ecosystem?

USGS Publications Warehouse

Boxall, Alistair; Sinclair, C.; Fenner, Kathrin; Kolpin, Dana W.; Maund, S.

2004-01-01

Although some regulatory schemes require information about the impacts of degradates on human and environmental health, that information does not exist for many compounds (25, 26). Pesticides are the exception. In this article, we bring together the available data to address the environmental behavior of degradates and their effects on organisms and discuss how to identify substances of potential concern. In addition, we cite gaps in the current knowledge and make recommendations for future research requirements. While the article focuses on pesticides, we believe these observations can be extended to biologically active compounds and some industrial substances.

Occurrence of selected pesticides and their metabolites in near-surface aquifers of the midwestern United States

USGS Publications Warehouse

Kolpin, D.W.; Michael, Thurman E.; Goolsby, D.A.

1996-01-01

The occurrence and distribution of selected pesticides and their metabolites were investigated through the collection of 837 water-quality samples from 303 wells across the Midwest. Results of this study showed that five of the six most frequently detected compounds were pesticide metabolites. Thus, it was common for a metabolite to be found more frequently in groundwater than its parent compound. The metabolite alachlor ethanesulfonic acid (alachlor-ESA; 2-[(2,6-diethylphenyl)(methoxymethyl)amino]-2-oxoethanesulfonic acid) was detected almost 10 times as frequently and at much higher concentrations than its parent compound alachlor (2-chloro-2‘,6‘-diethyl-N-(methoxymethyl)acetamide). The median detectable atrazine (2-chloro-4-ethylamino-6- isopropylamino-s-triazine) concentration was almost half that of atrazine residue (atrazine plus the two atrazine metabolites analyzed). Cyanazine amide [2-chloro-4-(1-carbamoyl-1-methylethylamino)-6-ethylamino-s-triazine] was detected almost twice as frequently as cyanazine (2-chloro-4-ethylamino-6-methylpropionitrileamino-s-triazine). Results show that information on pesticide metabolites is necessary to understand the environmental fate of pesticides. Consequently, if pesticide metabolites are not quantified, the effects of chemical use on groundwater quality would be substantially underestimated. Thus, continued research is needed to identify major degradation pathways for all pesticides and to develop analytical methods to determine their concentrations in water and other environmental media.

Spatial distribution of organic pollutants in industrial construction and demolition waste and their mutual interaction on an abandoned pesticide manufacturing plant.

PubMed

Huang, Sheng; Zhao, Xin; Sun, Yanqiu; Ma, Jianli; Gao, Xiaofeng; Xie, Tian; Xu, Dongsheng; Yu, Yi; Zhao, Youcai

2016-04-01

A comprehensive field investigation of organic pollutants was examined in industrial construction and demolition waste (ICDW) inside an abandoned pesticide manufacturing plant. Concentrations of eight types of pesticides, a metabolite and two intermediates were studied. The ICDW was under severe and long-term contamination by organophosphorus, intermediates and pyrethroid pesticide with mean concentrations of 23,429, 3538 and 179.4 mg kg(-1), respectively. FT-IR analysis suggested that physical absorption and chemical bonding were their mutual interaction forms. Patterns of total pesticide spatial distribution showed good correlations with manufacturing processes spreading all over the plant both in enclosed workshops and in residues randomly dumped outside, while bricks and coatings were the most vulnerable to pollutants. Ultimately the fate of the OPPs was diversified as the immersion of ICDW in water largely transferred the pollutants into aquatic systems while exposure outside did not largely lead to pesticide degradation. The adoption of centralized collections for the disposal of wastes could only eliminate part of the contaminated ICDW, probably due to lack of knowledge and criteria. Correlation matrix and cluster analysis indicated that regulated disposal and management of polluted ICDW was effective, thus presenting the requirement for its appropriate disposal.

Modelling Pesticide Leaching At Column, Field and Catchment Scales I. Analysis of Soil Variability At Field and Catchment Scales

NASA Astrophysics Data System (ADS)

Gärdenäs, A.; Jarvis, N.; Alavi, G.

The spatial variability of soil characteristics was studied in a small agricultural catch- ment (Vemmenhög, 9 km2) at the field and catchment scales. This analysis serves as a basis for assumptions concerning upscaling approaches used to model pesticide leaching from the catchment with the MACRO model (Jarvis et al., this meeting). The work focused on the spatial variability of two key soil properties for pesticide fate in soil, organic carbon and clay content. The Vemmenhög catchment (9 km2) is formed in a glacial till deposit in southernmost Sweden. The landscape is undulating (30 - 65 m a.s.l.) and 95 % of the area is used for crop production (winter rape, winter wheat, sugar beet and spring barley). The climate is warm temperate. Soil samples for or- ganic C and texture were taken on a small regular grid at Näsby Farm, (144 m x 144 m, sampling distance: 6-24 m, 77 points) and on an irregular large grid covering the whole catchment (sampling distance: 333 m, 46 points). At the field scale, it could be shown that the organic C content was strongly related to landscape position and height (R2= 73 %, p < 0.001, n=50). The organic C content of hollows in the landscape is so high that they contribute little to the total loss of pesticides (Jarvis et al., this meeting). Clay content is also related to landscape position, being larger at the hilltop locations resulting in lower near-saturated hydraulic conductivity. Hence, macropore flow can be expected to be more pronounced (see also Roulier & Jarvis, this meeting). The variability in organic C was similar for the field and catchment grids, which made it possible to krige the organic C content of the whole catchment using data from both grids and an uneven lag distance.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamel, D.R.

This paper identifies the kinds of risk assessments being done by or for the US Department of Agriculture (USDA) Forest Service. Summaries of data sources currently in use and the pesticide risk assessments completed by the agency or its contractors are discussed. An overview is provided of the agency`s standard operating procedures for the conduct of toxicological, ecological, environmental fate, and human health risk assessments.

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

Code of Federal Regulations, 2013 CFR

2013-07-01

.../pathogenicity study is the upland game. There is also the option to test the passerine if there is a concern... product. Notes that apply to an individual test including specific conditions, qualifications, or exceptions to the designated test are listed in paragraph (e) of this section. (b) Use patterns. Aquatic uses...

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

Code of Federal Regulations, 2012 CFR

2012-07-01

.../pathogenicity study is the upland game. There is also the option to test the passerine if there is a concern... product. Notes that apply to an individual test including specific conditions, qualifications, or exceptions to the designated test are listed in paragraph (e) of this section. (b) Use patterns. Aquatic uses...

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

Code of Federal Regulations, 2011 CFR

2011-07-01

.../pathogenicity study is the upland game. There is also the option to test the passerine if there is a concern... product. Notes that apply to an individual test including specific conditions, qualifications, or exceptions to the designated test are listed in paragraph (e) of this section. (b) Use patterns. Aquatic uses...

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

Code of Federal Regulations, 2010 CFR

2010-07-01

.../pathogenicity study is the upland game. There is also the option to test the passerine if there is a concern... product. Notes that apply to an individual test including specific conditions, qualifications, or exceptions to the designated test are listed in paragraph (e) of this section. (b) Use patterns. Aquatic uses...

40 CFR 161.108 - Relationship of Pesticide Assessment Guidelines to data requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Environmental Fate PB83-153973 161.290 O Residue Chemistry PB83-153961 161.240 R Spray Drift Evaluation PB84... Guidelines to data requirements. 161.108 Section 161.108 Protection of Environment ENVIRONMENTAL PROTECTION...: Subdivision Title NTIS order no. Corresponding section(s) in this part D Product Chemistry PB83-153890 161.150...

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

Code of Federal Regulations, 2014 CFR

2014-07-01

..., residential, and industrial). Terrestrial uses include: Food, Feed, Non-Food, Forestry, Residential outdoor, greenhouse (food and food), Indoor (food and nonfood), and Industrial. (c) Key. R=Required; CR=Conditionally... Indoor Food/Nonfood Industrial Test Substance Test Notes 885.4050 Avian oraltoxicity NR R R R R NR NR NR...

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

Code of Federal Regulations, 2013 CFR

2013-07-01

..., residential, and industrial). Terrestrial uses include: Food, Feed, Non-Food, Forestry, Residential outdoor, greenhouse (food and food), Indoor (food and nonfood), and Industrial. (c) Key. R=Required; CR=Conditionally... Indoor Food/Nonfood Industrial Test Substance Test Notes 885.4050 Avian oraltoxicity NR R R R R NR NR NR...

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

Code of Federal Regulations, 2012 CFR

2012-07-01

..., residential, and industrial). Terrestrial uses include: Food, Feed, Non-Food, Forestry, Residential outdoor, greenhouse (food and food), Indoor (food and nonfood), and Industrial. (c) Key. R=Required; CR=Conditionally... Indoor Food/Nonfood Industrial Test Substance Test Notes 885.4050 Avian oraltoxicity NR R R R R NR NR NR...

Polyethylene film incorporation into the horticultural soil of small periurban production units in Argentina.

PubMed

Ramos, Laura; Berenstein, Giselle; Hughes, Enrique A; Zalts, Anita; Montserrat, Javier M

2015-08-01

Horticulture makes intensive use of soil and extensive use of polyethylene (PE) sheeting and pesticides, producing an environment where the dynamics between soil and plastics can affect pesticide fate. We have determined that the presence of plastic residues in the horticultural soil of small production units equals 10% of the soil area, being meso and macro-sections the predominant fragment sizes. All soil samples were taken from different plots located in Cuartel V, Moreno district, in the suburbs of Buenos Aires city, Argentina. Laboratory experiments were conducted to see the relations among pesticide, soil and PE film. Endosulfan recovery from LDPE films (25μm and 100μm) was studied, observing evidence that indicated migration to the inside of the plastic matrix. To further analyze the dynamics of pesticide migration to soil and atmosphere, experiments using chlorpyrifos, procymidone and trifluralin were performed in soil-plastic-atmosphere microenvironments, showing that up to 24h significant amounts of pesticides moved away from the PE film. To determine whether PE residues could act as potential pesticide collector in soil, column elution experiments were done using chlorpyrifos, procymidone and trifluralin. Results showed an important pesticide accumulation in the mulch film (584μg-2284μg pesticide/g plastic) compared to soil (13μg-32μg pesticide/g soil). Finally, chemical and photochemical degradation of deltamethrin adsorbed in PE film was studied, finding a protective effect on hydrolysis but no protective effect on photodegradation. We believe that a deeper understanding of the dynamics among soil, plastic and pesticides in horticultural productive systems may contribute to alert for the implications of PE use for plastic sheeting. Copyright © 2015 Elsevier B.V. All rights reserved.

From a microcosm to the catchment scale: studying the fate of organic runoff pollutants in aquatic ecosystems

NASA Astrophysics Data System (ADS)

Böttcher, T.; Schroll, R.

2009-04-01

Spray-drift, drainage, erosion and runoff events are the major causes responsible for deportation of agrochemicals as micropollutants to aquatic non-target sites. These processes can lead to the contamination of nearby freshwater ecosystems with considerably high concentrations of xenobiotics. Thus, it is important to unravel the fate of these pollutants and to evaluate their ecological effects. A novel approach to address this goal was established by the development of a microcosm with multiple sampling abilities enabling quantitative assessment of organic volatilisation, mineralization, metabolization and distribution within the aquatic ecosystem. This microcosm system was designed to support modelling approaches of the catchment scale and gain insights into the fate of pesticides simulating a large scale water body. The potential of this microcosm was exemplified for Isoproturon (IPU), a phenylurea derived systemic herbicide, which is frequently found as contaminant in water samples and with the free-floating macrophyte Lemna minor as non-target species, that is common to occur in rural water bodies. During 21 days exposure time, only a small amount of 14C labeled IPU was removed from the aquatic medium. The major portion (about 5%) was accumulated by Lemna minor resulting in a BCF of 15.8. IPU-volatilisation was very low with 0.13% of the initially applied herbicide. Only a minor amount of IPU was completely metabolized, presumably by rhizosphere microorganisms and released as 14CO2. The novel experimental system allowed to quantitatively investigate the fate of IPU and showed a high reproducibility with a mean average 14C-recovery rate of 97.1

The fate of isoproturon in a freshwater microcosm with Lemna minor as a model organism.

PubMed

Böttcher, Thomas; Schroll, Reiner

2007-01-01

Degradation, bioaccumulation and volatile loss of the 14C-labeled phenylurea herbicide isoproturon (IPU) was examined in a freshwater microcosm with the free floating macrophyte species Lemna minor during a 21-day exposure time. Isoproturon volatilisation was very low with 0.13+/-0.01% of the initially applied herbicide. Only a minor amount of the herbicide was completely metabolised, presumably by rhizosphere microorganisms and released as 14CO2. In total, about 9% isoproturon was removed from the aquatic medium during 21 days. The major portion of the pesticide was removed by bioaccumulation of Lemna minor (5.0+/-0.8%) and the bioconcentration factor (BCF) based on freshweight was 15.8+/-0.2. However, this study indicated a high persistence of IPU in freshwater ecosystems and a potential hazard due to bioaccumulation in non-target species. The novel experimental system of this study, developed for easy use and multiple sampling abilities, enabled quantitatively studying the fate of isoproturon and showed high reproducibility with a mean average (14)C-recovery rate of 97.1+/-0.7%.

Specific persistence and fate of a soil active herbicide-hexazinone and implications for management

Treesearch

J.L. Michael

2001-01-01

Federal pesticide regulation began officially in 1947 with the promulgation of P.L. 80-104, also known as the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). This early version was administered by the U.S. Department of Agriculture. Responsibility for administration of FIFRA was transferred to the U.S. Environmental Protection Agency (EPA) when it was...

40 CFR 158.2060 - Biochemical pesticides nontarget organisms and environmental fate data requirements table.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., one avian dietary, one acute freshwater fish, one acute freshwater invertebrate study, plant toxicity... R R CR R CR TGAI, EP 2, 3, 4, 5 850.1010 Aquatic invertebrate acute toxicity, freshwater R R CR R CR....1500 Freshwater fish/invertebrate testing CR CR NR CR NR TGAI 10 850.1025850.1035 850.1045 850.1055 850...

Aerial ULV application of permethrin against adult mosquitoes over open field and medium density canopy habitat in a hot-temperate zone

USDA-ARS?s Scientific Manuscript database

Although aerial ULV application of adulticides is a common adult mosquito control strategy, not enough is known about the fate of the pesticide or its efficacy over different habitats. Dye labeling of droplets is used to evaluate ULV applications, and, by inference, their efficacy. Placement of cage...

Altitudinal and chiral signature of persistent organochlorine pesticides in air, soil, and spruce needles (Picea abies) of the Alps.

PubMed

Shen, Heqing; Henkelmann, Bernhard; Levy, Walkiria; Zsolnay, Adam; Weiss, Peter; Jakobi, Gert; Kirchner, Manfred; Moche, Wolfgang; Braun, Katharina; Schramm, Karl-Werner

2009-04-01

The present study investigated the distribution, transportation, and biodegradation of the selected chiral persistent organochlorine pesticides (OCP) in the Alps. In the complex environment, we found the movement and fate of OCP could be defined by many factors. Taking HCE as an example, below the timberline its accumulation from air into SPMD increased with altitude and seasonally changed, but the trends reversed above the timberline. In soil, the tendency of HCE concentrations vs organic materials followed a sigmoid curve, and HCE concentration-altitude correlations are positive in central Alps but negative in southern Alps. The HCE enantiomeric ratios (ERs) in soil correlated to HCE isomers concentrations, the humus pH values, and the sampling site altitudes. HCE shift from humus to mineral soil can also be traced by ERs. The altitudinal and longitudinal trends in needles suggested that alpha-HCH has a more complex movementthan HCE in Alps. In conclusion, altitude conducted condensation, plant canopies, organic material in soil, and geographic specific precipitations may affect OCP distributions and transportation, whereas altitude conducted temperature and soil pH could dictate their fate in the environment.

Light induced heterogeneous ozone processing on the pesticides adsorbed on silica particles

NASA Astrophysics Data System (ADS)

Socorro, J.; Désert, M.; Quivet, E.; Gligorovski, S.; Wortham, H.

2013-12-01

In France, in 2010, the sales of pesticides reached 1.8 billion euros for 61 900 tons of active ingredients, positioning France as a first European consumer of pesticides, as reported by the European Crop Protection Association. About 19 million hectares of crops are sprayed annually with pesticides, i.e., 35% of the total surface area of France. This corresponds to an average pesticide dose of 3.2 kg ha-1. The consumption of herbicide and fungicide is favoured in comparison to the use of insecticides in France and the other European countries, as well. The partitioning of pesticides between the gas and particulate phases influences the atmospheric fate of these compounds such as their photo-chemical degradation. There is much uncertainty concerning the behavior of the pesticides in the atmosphere. Especially, there is a gap of knowledge concerning the degradation of the pesticides induced by heterogeneous reactions in absence and especially in presence of solar light. Considering that most of the pesticides currently used are semi-volatile, it is of crucial importance to investigate the heterogeneous reactivity of particulate pesticides with light and with atmospheric oxidants such as ozone and OH radical. The aim of the present work is to evaluate the light induced heterogeneous ozonation of suspended pesticide particles. 8 pesticides (cyprodinil, deltamethrin, difenoconazole, fipronil, oxadiazon, pendimethalin, permethrin and tetraconazole) were chosen for their physico-chemical properties and their concentration levels in the PACA (Région Provence-Alpes-Côte d'Azur) region, France. Silica particles with well-known properties were chosen as model particles of atmospheric relevance. Kinetic rate constants were determined to allow estimate the atmospheric lifetimes relating to ozone. The rate constants were determined as follows: k = (6.6 × 0.2) 10-19, (7.2 × 0.3) 10-19, (5.1 × 0.5) 10-19, (3.9 × 0.3) 10-19 [cm3 molecules-1 s-1] for Cyprodinil, delthamethrine, permethrine and pendimethaline, respectively. Concerning the other four pesticides under study i.e. difenoconazole, fipronil, oxadiazon and tetraconazole the obtained rate constants were extremely slow, < 3.9 10-19 [cm3 molecules-1 s-1]. In addition, we identified the condensed phase products in such heterogeneous reactions of ozone with the particulate pesticides by GC-MS coupled with the derivatization technique. The gas-phase products were followed on-line by PTR-MS-TOF. The obtained results will allow to recognize the impact of the pesticides and their degradation products on the human health, and to make recommendations in order to reduce population exposure to the pesticide plume. The results of this work will contribute to better describe and understand the pollution by phyto-sanitary products on the regional scale, which constitutes a necessary step in the development of environmental strategies. As a result the obtained results will help in the development of future environmental strategies to better understand and control phyto-sanitary product application and human exposure.

Development and validation of a simulation method, PeCHREM, for evaluating spatio-temporal concentration changes of paddy herbicides in rivers.

PubMed

Imaizumi, Yoshitaka; Suzuki, Noriyuki; Shiraishi, Fujio; Nakajima, Daisuke; Serizawa, Shigeko; Sakurai, Takeo; Shiraishi, Hiroaki

2018-01-24

In pesticide risk management in Japan, predicted environmental concentrations are estimated by a tiered approach, and the Ministry of the Environment also performs field surveys to confirm the maximum concentrations of pesticides with risk concerns. To contribute to more efficient and effective field surveys, we developed the Pesticide Chemicals High Resolution Estimation Method (PeCHREM) for estimating spatially and temporally variable emissions of various paddy herbicides from paddy fields to the environment. We used PeCHREM and the G-CIEMS multimedia environmental fate model to predict day-to-day environmental concentration changes of 25 herbicides throughout Japan. To validate the PeCHREM/G-CIEMS model, we also conducted a field survey, in which river waters were sampled at least once every two weeks at seven sites in six prefectures from April to July 2009. In 20 of 139 sampling site-herbicide combinations in which herbicides were detected in at least three samples, all observed concentrations differed from the corresponding prediction by less than one order of magnitude. We also compared peak concentrations and the dates on which the concentrations reached peak values (peak dates) between predictions and observations. The peak concentration differences between predictions and observations were less than one order of magnitude in 66% of the 166 sampling site-herbicide combinations in which herbicide was detected in river water. The observed and predicted peak dates differed by less than two weeks in 79% of these 166 combinations. These results confirm that the PeCHREM/G-CIEMS model can improve the efficiency and effectiveness of surveys by predicting the peak concentrations and peak dates of various herbicides.

Glyphosate fate in soils when arriving in plant residues.

PubMed

Mamy, Laure; Barriuso, Enrique; Gabrielle, Benoît

2016-07-01

A significant fraction of pesticides sprayed on crops may be returned to soils via plant residues, but its fate has been little documented. The objective of this work was to study the fate of glyphosate associated to plants residues. Oilseed rape was used as model plant using two lines: a glyphosate-tolerant (GT) line and a non-GT one, considered as a crucifer weed. The effects of different fragmentation degrees and placements in soil of plant residues were tested. A control was set up by spraying glyphosate directly on the soil. The mineralization of glyphosate in soil was slower when incorporated into plant residues, and the amounts of extractable and non-extractable glyphosate residues increased. Glyphosate availability for mineralization increased when the size of plant residues decreased, and as the distribution of plant residues in soil was more homogeneous. After 80 days of soil incubation, extractable (14)C-residues mostly involved one metabolite of glyphosate (AMPA) but up to 2.6% of initial (14)C was still extracted from undecayed leaves as glyphosate. Thus, the trapping of herbicides in plant materials provided a protection against degradation, and crops residues returns may increase the persistence of glyphosate in soils. This pattern appeared more pronounced for GT crops, which accumulated more non-degraded glyphosate in their tissues. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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 monitored systematically from August 2008 to August 2009. Methods: Water samples (0.5 L) were collected in borosilicate bottles with Teflon caps, pre-filtered with glass wool (Roth, Germany) and glass fibre filter (Millipore, USA), solid-phase extracted (Phenomenex, C18-E) and quantified using GC-MS (Agilent 6890). For quality assurance samples and blanks were spiked with a surrogate standard (d-HCH). The recovery of the surrogate standard was used to monitor for matrix effects and sample processing errors. Surrogate recovery was evaluated by a recovery standard (Fluoren-d10) spiked to the sample after the extraction. Results: A total of 434 samples (253 samples in Ba Lang, 119 samples in An Long and 62 drinking water samples) were collected from August 2008 to August 2009. In An Long 13 of the 15 target compounds were detected in water samples. Average residue concentrations ranged from 0.01 to 3.96 ?g/l. The fungicide isoprothiolane and the insecticide buprofezin occurred with the highest concentrations (up to 20.77 and 16.53 ?g/l, respectively). In Ba Lang, 12 of the 15 monitored pesticides were detected with an average concentration from 0.01 to 0.30 ?g/l. The fungicide isoprothiolane was detected with highest (up to 12.86 ?g/l). In 70% of all samples more than four different pesticides were detected. Their effect may add up and pose risk to humans and aquatic organisms. In rural areas surface water is frequently used as drinking water source. First results from a sampling program of drinking water indicate that locally used water treatment methods (precipitation with aluminium sulfate followed by boiling) were not appropriate to reduce the pesticide exposure of the consumer. Through evaporation, boiling of drinking water even increased the concentrations of some non-volatile pesticides. References Carvalho, F. P., Villeneuve, J.P., Cattini, C., Tolosa, I., Thuan, D. D., Nhan, D. D., 2008. Agrochemical and polychlorobyphenyl (PCB) residues in the Mekong River delta, Vietnam. Marine Pollution Bulletin 56, 1476-1485. Dasgupta S., Meisner C., Wheeler D., Nhan L. T., Khuc X., 2005. Pesticide poisoning of farm workers: implications of blood test results from Vietnam. World Bank Policy Research Working Paper 3624. Dung, N.H., Dung, T.T., 2003. Economic and health consequences of pesticide use in paddy production in the Mekong Delta, Vietnam. Economy and environment case studies in Vietnam. Economy and environment program for Southeast Asia. Margni, M., Rossier, D., Crettaz, P., Jolliet, O., 2002. Life cycle impact assessment of pesticides on human health and ecosystems. Agriculture, Ecosystems and Environment 93, 379-392. Mekong River Committee Secretariat (MRCS), 2007. Environmental health concerns related to agro-chemical use in the Mekong Delta. Environment training case studies. Minh, N. H., Minh, T. B., Kajiwara, N., Kunisue, T., Iwata, H., Viet P.H., Tu, N. P. C., Tuyen, B. C., Tanabe, S., 2007. Pollution sources and occurrences of selected persistent organic pollutants (POPs) in sediments of the Mekong River delta, South Vietnam. Chemosphere. 67, 1794-1801. Phuong, D. M., Gopalakrishnan, C., 2003. An application of the contingent valuation method to estimate the loss of value of water resources due to pesticide contamination: the case of the Mekong Delta, Vietnam',International. Journal of Water Resources Development,19, 617-633.

Investigation of Pesticide Penetration and Persistence on Harvested and Live Basil Leaves Using Surface-Enhanced Raman Scattering Mapping.

PubMed

Yang, Tianxi; Zhao, Bin; Kinchla, Amanda J; Clark, John M; He, Lili

2017-05-03

Understanding pesticide behavior in plants is important for effectively applying pesticides and in reducing pesticide exposures from ingestion. This study aimed to investigate the penetration and persistence of pesticides applied on harvested and live basil leaves. Surface-enhanced Raman scattering (SERS) mapping was applied for in situ and real-time tracking of pesticides over time using gold nanoparticles as probes. The results showed that, after surface exposure of 30 min to 48 h, pesticides (10 mg/L) penetrated more rapidly and deeply into the live leaves than the harvested leaves. The systemic pesticide thiabendazole and the nonsystemic pesticide ferbam can penetrate into the live leaves with depths of 225 and 130 μm, respectively, and the harvested leaves with depths of 180 and 18 μm, respectively, after 48 h of exposure. The effects of leaf integrity and age on thiabendazole penetration were also evaluated on live basil leaves after 24 h of exposure. Thiabendazole (10 mg/L) when applied onto intact leaves penetrated deeper (170 μm) than when applied onto damaged leaves (80 μm) prepared with 20 scrapes on the top surface of the leaves. Older leaves with a wet mass of 0.204 ± 0.019 g per leaf (45 days after leaf out) allowed more rapid and deeper penetration of pesticides (depth of 165 μm) than younger leaves with a wet mass of 0.053 ± 0.007 g per leaf (15 days after leaf out, depth of 95 μm). The degradation of thiabendazole on live leaves was detected after 1 week, whereas the apparent degradation of ferbam was detected after 2 weeks. In addition, the removal of pesticides from basil was more efficient when compared with other fresh produce possibly due to the specific gland structure of basil leaves. The information obtained here provides a better understanding of the behavior and biological fate of pesticides on plants.

Production of apple-based baby food: changes in pesticide residues.

PubMed

Kovacova, Jana; Kocourek, Vladimir; Kohoutkova, Jana; Lansky, Miroslav; Hajslova, Jana

2014-01-01

Apples represent the main component of most fruit-based baby food products. Since not only fruit from organic farming, but also conventionally grown fruit is used for baby food production, the occurrence of pesticide residues in the final product is of high concern. To learn more about the fate of these hazardous compounds during processing of contaminated raw material, apples containing altogether 21 pesticide residues were used for preparation of a baby food purée both in the household and at industrial scale (in the baby food production facility). Within both studies, pesticide residues were determined in raw apples as well as in final products. Intermediate product and by-product were also analysed during the industrial process. Determination of residues was performed by a sensitive multi-detection analytical method based on liquid or gas chromatography coupled with mass spectrometry. The household procedure involved mainly the cooking of unpeeled apples, and the decrease of residues was not extensive enough for most of the studied pesticides; only residues of captan, dithianon and thiram dropped significantly (processing factors less than 0.04). On the other hand, changes in pesticide levels were substantial for all tested pesticides during apple processing in the industrial baby food production facility. The most important operation affecting the reduction of residues was removal of the by-products after pulping (rest of the peel, stem, pips etc.), while subsequent sterilisation has an insignificant effect. Also in this case, captan, dithianon and thiram were identified as pesticides with the most evident decrease of residues.

Methods of analysis and quality-assurance practices of the U.S. Geological Survey organic laboratory, Sacramento, California; determination of pesticides in water by solid-phase extraction and capillary-column gas chromatography/mass spectrometry

USGS Publications Warehouse

Crepeau, Kathryn L.; Domagalski, Joseph L.; Kuivila, Kathryn

1994-01-01

Analytical method and quality-assurance practices were developed for a study of the fate and transport of pesticides in the Sacramento-San Joaquin Delta and the Sacramento and San Joaquin River. Water samples were filtered to remove suspended parti- culate matter and pumped through C-8 solid-phase extraction cartridges to extract the pesticides. The cartridges were dried with carbon dioxide, and the pesticides were eluted with three 2-milliliter aliquots of hexane:diethyl ether (1:1). The eluants were analyzed using capillary-column gas chromatography/mass spectrometry in full-scan mode. Method detection limits for analytes determined per 1,500-milliliter samples ranged from 0.006 to 0.047 microgram per liter. Recoveries ranged from 47 to 89 percent for 12 pesticides in organic-free, Sacramento River and San Joaquin River water samples fortified at 0.05 and 0.26 microgram per liter. The method was modified to improve the pesticide recovery by reducing the sample volume to 1,000 milliliters. Internal standards were added to improve quantitative precision and accuracy. The analysis also was expanded to include a total of 21 pesticides. The method detection limits for 1,000-milliliter samples ranged from 0.022 to 0.129 microgram per liter. Recoveries ranged from 38 to 128 percent for 21 pesticides in organic-free, Sacramento River and San Joaquin River water samples fortified at 0.10 and 0.75 microgram per liter.

Fate and transport of pesticides in the ground water systems of southwest Georgia, 1993-2005

USGS Publications Warehouse

Dalton, M.S.; Frick, E.A.

2008-01-01

Modern agricultural practices in the United States have resulted in nearly unrivaled efficiency and productivity. Unfortunately, there is also the potential for release of these compounds to the environment and consequent adverse affects on wildlife and human populations. Since 1993, the National Water-Quality Assessment (NAWQA) program of the U.S. Geological Survey has evaluated water quality in agricultural areas to address these concerns. The objective of this study is to evaluate trends in pesticide concentrations from 1993-2005 in the surficial and Upper Floridan aquifers of southwest Georgia using pesticide and pesticide degradate data collected for the NAWQA program. There were six compounds - five herbicides and one degradate - that were detected in more than 20% of samples: atrazine, deethylatrazine (DEA), metolachlor, alachlor, floumeturon, and tebuthiuron. Of the 128 wells sampled during the study, only eight wells had pesticide concentrations that either increased (7) or decreased (1) on a decadal time scale. Most of the significant trends were increasing concentrations of pesticides in older water; median pesticide concentrations did not differ between the surficial and Upper Floridan aquifers from 1993 and 2005. Deethylatrazine, in the Upper Floridan aquifer, was the only compound that had a significant change (increase) in concentration during the study. The limited number of wells with increases in pesticide concentrations suggest that ground-water sources of these compounds are not increasing in concentration over the time scale represented in this study. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

Pesticides in near-surface aquifers: An assessment using highly sensitive analytical methods and tritium

USGS Publications Warehouse

Kolpin, D.W.; Goolsby, D.A.; Thurman, E.M.

1995-01-01

In 1992, the U.S. Geological Survey (USGS) determined the distribution of pesticides in near-surface aquifers of the midwestern USA to be much more widespread than originally determined during a 1991 USGS study. The frequency of pesticide detection increased from 28.4% during the 1991 study to 59.0% during the 1992 study. This increase in pesticide detection was primarily the result of a more sensitive analytical method that used reporting limits as much as 20 times lower than previously available and a threefold increase in the number of pesticide metabolites analyzed. No pesticide concentrations exceeded the U.S. Environmental Protection Agency's (USEPAs) maximum contaminant levels or health advisory levels for drinking water. However, five of the six most frequently detected compounds during 1992 were pesticide metabolites that currently do not have drinking water standards determined. The frequent presence of pesticide metabolites for this study documents the importance of obtaining information on these compounds to understand the fate and transport of pesticides in the hydrologic system. It appears that the 56 parent compounds analyzed follow similar pathways through the hydrologic system as atrazine. When atrazine was detected by routine or sensitive analytical methods, there was an increased likelihood of detecting additional parent compounds. As expected, the frequency of pesticide detection was highly dependent on the analytical reporting limit. The number of atrazine detections more than doubled as the reporting limit decreased from 0.10 to 0.01 µg/L. The 1992 data provided no indication that the frequency of pesticide detection would level off as improved analytical methods provide concentrations below 0.003 µg/L. A relation was determined between groundwater age and the frequency of pesticide detection, with 15.8% of the samples composed of pre-1953 water and 70.3% of the samples of post-1953 water having a detection of at least one pesticide or metabolite. Pre-1953 water is less likely to contain pesticides because it tends to predate the use of pesticides to increase crop production in the Midwest. Pre-1953 water was more likely to occur in the near-surface bedrock aquifers (50.0%) than in the near-surface unconsolidated aquifers (9.1%) sampled.

The legacy of organochlorine pesticide usage in a tropical semi-arid region (Jaguaribe River, Ceará, Brazil): Implications of the influence of sediment parameters on occurrence, distribution and fate.

PubMed

Oliveira, André H B; Cavalcante, Rivelino M; Duaví, Wersângela C; Fernandes, Gabrielle M; Nascimento, Ronaldo F; Queiroz, Maria E L R; Mendonça, Kamila V

2016-01-15

Between the 1940s and 1990s, immeasurable amounts of organochlorine pesticides (OCPs) were used in endemic disease control campaigns and agriculture in the tropical semi-arid regions of Brazil. The present study evaluated the legacy of banned OCP usage, considering the levels, ecological risk and dependence on sediment physicochemical properties for the fate and distribution in the Jaguaribe River. The sum concentration of OCPs (ΣOCPs) ranged from 5.09 to 154.43 ng·g(-1), comparable to the levels found in other tropical and subtropical regions that have traditionally used OCPs. The environmental and geographical distribution pattern of p,p-DDT, p,p-DDD and p,p-DDE shows that the estuarine zone contained more than 3.5 times the levels observed in the fluvial region, indicating that the estuary of the Jaguaribe River is a sink. The temporal pattern indicates application of dichloro-diphenyl-trichloroethanes (DDTs) in the past; however, there is evidence of recent input of these pesticides. High ecological risk was observed for levels of γ-hexachlorocyclohexanes (γ-HCH) and heptachlor, and moderate ecological risk was observed for levels of DDTs in sediments from the Jaguaribe River. The heptachlor, γ-HCH and hexachlorobenzene (HCB) concentrations depend on the organic and inorganic fractions of sediment from the Jaguaribe River, whereas the p,p-DDE, p,p-DDD, p,p-DDT and α-endosulfan concentrations depend solely on the organic fraction of the sediment.

Classification and modelling of non-extractable residue (NER) formation from xenobiotics in soil - a synthesis

NASA Astrophysics Data System (ADS)

Kaestner, Matthias; Nowak, Karolina; Miltner, Anja; Trapp, Stefan; Schaeffer, Andreas

2014-05-01

This presentation provides a comprehensive overview about the formation of non-extractable residues (NER) from organic pesticides and contaminants in soil and tries classifying the different types. Anthropogenic organic chemicals are deliberately (e.g. pesticides) or unintentionally (e.g. polyaromatic hydrocarbons [PAH], chlorinated solvents, pharmaceuticals) released in major amounts to nearly all compartments of the environment. Soils and sediments as complex matrices provide a wide variety of binding sites and are the major sinks for these compounds. Many of the xenobiotics entering soil undergo turnover processes and can be volatilised, leached to the groundwater, degraded by microorganisms or taken up and enriched by living organisms. Xenobiotic NER may be derived from parent compounds and primary metabolites that are sequestered (sorbed or entrapped) within the soil organic matter (type I NER) or can be covalently bound (type II NER). Especially type I NER may pose a considerably environmental risk of potential release. However, NER resulting from productive biodegradation, which means the conversion of carbon (or nitrogen) from the compounds into microbial biomass molecules during microbial degradation (type III, bioNER), do not pose any risk. Experimental and analytical approaches to clearly distinguish between the types are provided and a model to prospectively estimate their fate in soil is proposed.

40 CFR 158.2060 - Biochemical pesticides nontarget organisms and environmental fate data requirements table.

Code of Federal Regulations, 2014 CFR

2014-07-01

....1350 850.1400 850.1500 Marine/Estuarine fish/invertebrate animal testing CR CR NR CR NR TGAI 10 850... testing, and a honeybee acute contact study. (2) The data in this section are not required for arthropod... Avian Testing 850.2100 Avian acute oral toxicity R R CR R CR TGAI, EP 1, 2, 3, 4 850.2200 Avian dietary...

40 CFR 158.2060 - Biochemical pesticides nontarget organisms and environmental fate data requirements table.

Code of Federal Regulations, 2012 CFR

2012-07-01

....1350 850.1400 850.1500 Marine/Estuarine fish/invertebrate animal testing CR CR NR CR NR TGAI 10 850... testing, and a honeybee acute contact study. (2) The data in this section are not required for arthropod... Avian Testing 850.2100 Avian acute oral toxicity R R CR R CR TGAI, EP 1, 2, 3, 4 850.2200 Avian dietary...

40 CFR 158.2060 - Biochemical pesticides nontarget organisms and environmental fate data requirements table.

Code of Federal Regulations, 2011 CFR

2011-07-01

....1350 850.1400 850.1500 Marine/Estuarine fish/invertebrate animal testing CR CR NR CR NR TGAI 10 850... testing, and a honeybee acute contact study. (2) The data in this section are not required for arthropod... Avian Testing 850.2100 Avian acute oral toxicity R R CR R CR TGAI, EP 1, 2, 3, 4 850.2200 Avian dietary...

40 CFR 158.2060 - Biochemical pesticides nontarget organisms and environmental fate data requirements table.

Code of Federal Regulations, 2013 CFR

2013-07-01

....1350 850.1400 850.1500 Marine/Estuarine fish/invertebrate animal testing CR CR NR CR NR TGAI 10 850... testing, and a honeybee acute contact study. (2) The data in this section are not required for arthropod... Avian Testing 850.2100 Avian acute oral toxicity R R CR R CR TGAI, EP 1, 2, 3, 4 850.2200 Avian dietary...

Influence of Soil Factors on the Stereoselective Fate of a Novel Chiral Insecticide, Paichongding, in Flooded Paddy Soils.

PubMed

Li, Juying; Huang, Tuo; Li, Lizong; Ding, Tengda; Zhu, Hong; Yang, Bo; Ye, Qingfu; Gan, Jay

2016-11-02

In this study, the fate of paichongding was investigated in three soils with contrasting soil properties. In general, low soil pH has the potential to retard the mineralization and promote the dissipation of paichongding and the formation of its primary transformation product and to accelerate the formation of bound residue. The dissipation of paichongding stereoisomers was very fast and diastereoselective. This selectivity was found only between diastereomers and not between enantiomers and was observed to be soil dependent. In the acidic soil, the enantiomers (5R,7R)- and (5S,7S)-paichongding were degraded more quickly than (5R,7S)- and (5S,7R)-paichongding, whereas a contrary trend was observed in the neutral soil, and such selectivity did not occur in the alkaline soil. The OM and clay contents also played important roles in the fate of paichongding. This effect of soil properties should be considered in risk assessment of chiral pesticides and their application in the field.

Risk assessment considerations with regard to the potential impacts of pesticides on endangered species.

PubMed

Brain, Richard A; Teed, R Scott; Bang, JiSu; Thorbek, Pernille; Perine, Jeff; Peranginangin, Natalia; Kim, Myoungwoo; Valenti, Ted; Chen, Wenlin; Breton, Roger L; Rodney, Sara I; Moore, Dwayne R J

2015-01-01

Simple, deterministic screening-level assessments that are highly conservative by design facilitate a rapid initial screening to determine whether a pesticide active ingredient has the potential to adversely affect threatened or endangered species. If a worst-case estimate of pesticide exposure is below a very conservative effects metric (e.g., the no observed effects concentration of the most sensitive tested surrogate species) then the potential risks are considered de minimis and unlikely to jeopardize the existence of a threatened or endangered species. Thus by design, such compounded layers of conservatism are intended to minimize potential Type II errors (failure to reject a false null hypothesis of de minimus risk), but correspondingly increase Type I errors (falsely reject a null hypothesis of de minimus risk). Because of the conservatism inherent in screening-level risk assessments, higher-tier scientific information and analyses that provide additional environmental realism can be applied in cases where a potential risk has been identified. This information includes community-level effects data, environmental fate and exposure data, monitoring data, geospatial location and proximity data, species biology data, and probabilistic exposure and population models. Given that the definition of "risk" includes likelihood and magnitude of effect, higher-tier risk assessments should use probabilistic techniques that more accurately and realistically characterize risk. Moreover, where possible and appropriate, risk assessments should focus on effects at the population and community levels of organization rather than the more traditional focus on the organism level. This document provides a review of some types of higher-tier data and assessment refinements available to more accurately and realistically evaluate potential risks of pesticide use to threatened and endangered species. © 2014 SETAC.

Fate of iprovalicarb, indoxacarb, and boscalid residues in grapes and wine by GC-ITMS analysis.

PubMed

Angioni, Alberto; Dedola, Fabrizio; Garau, Vincenzo Luigi; Schirra, Mario; Caboni, Pierluigi

2011-06-22

The behavior in field and the transfer from grapes to wine during winemaking of iprovalicarb, indoxacarb, and boscalid was studied. The residue levels found in grapes were far below the MRLs set for grapes in EU, accounting at harvest time 0.81, 0.43, and 4.23 mg/kg for iprovalicarb, indoxacarb, and boscalid, respectively. The residue levels in the samples treated with boscalid may have residual problems (due to an accumulation effect) if repeated field treatments will be performed. Winemaking experiments showed a complete transfer of all pesticide from grapes to the must, while in wine the residues were low or negligible due to the adsorbing effect of lees and pomace. The clarification experiments showed a good removal of pesticide residues from the wine media, for all pesticides. The GC-ITMS method showed good performance with adequate recoveries ranging from 75 to 115%, and good method limits of quantitation (LOQs) and of determination (LODs) far below MRLs.

Complex mixtures of dissolved pesticides show potential aquatic toxicity in a synoptic study of Midwestern U.S. streams

USGS Publications Warehouse

Nowell, Lisa H.; Moran, Patrick W.; Schmidt, Travis S.; Norman, Julia E.; Nakagaki, Naomi; Shoda, Megan E.; Mahler, Barbara J.; Van Metre, Peter C.; Stone, Wesley W.; Sandstrom, Mark W.; Hladik, Michelle L.

2018-01-01

Aquatic organisms in streams are exposed to pesticide mixtures that vary in composition over time in response to changes in flow conditions, pesticide inputs to the stream, and pesticide fate and degradation within the stream. To characterize mixtures of dissolved-phase pesticides and degradates in Midwestern streams, a synoptic study was conducted at 100 streams during May–August 2013. In weekly water samples, 94 pesticides and 89 degradates were detected, with a median of 25 compounds detected per sample and 54 detected per site. In a screening-level assessment using aquatic-life benchmarks and the Pesticide Toxicity Index (PTI), potential effects on fish were unlikely in most streams. For invertebrates, potential chronic toxicity was predicted in 53% of streams, punctuated in 12% of streams by acutely toxic exposures. For aquatic plants, acute but likely reversible effects on biomass were predicted in 75% of streams, with potential longer-term effects on plant communities in 9% of streams. Relatively few pesticides in water—atrazine, acetochlor, metolachlor, imidacloprid, fipronil, organophosphate insecticides, and carbendazim—were predicted to be major contributors to potential toxicity. Agricultural streams had the highest potential for effects on plants, especially in May–June, corresponding to high spring-flush herbicide concentrations. Urban streams had higher detection frequencies and concentrations of insecticides and most fungicides than in agricultural streams, and higher potential for invertebrate toxicity, which peaked during July–August. Toxicity-screening predictions for invertebrates were supported by quantile regressions showing significant associations for the Benthic Invertebrate-PTI and imidacloprid concentrations with invertebrate community metrics for MSQA streams, and by mesocosm toxicity testing with imidacloprid showing effects on invertebrate communities at environmentally relevant concentrations. This study documents the most complex pesticide mixtures yet reported in discrete water samples in the U.S. and, using multiple lines of evidence, predicts that pesticides were potentially toxic to nontarget aquatic life in about half of the sampled streams.

Military Smokes and Obscurants Fate and Effects: A Literature Review Relative to Threatened and Endangered Species

DTIC Science & Technology

2004-12-01

1999. Use of Aquatic Plants and Algae for Decontamination of Waters Pol- luted with Chlorinated Alkanes. Int J Phytoremediation . 1(3):203-226. An...Terres- trial Plants. Int J Phytoremediation . 3(1):13-40. Laboratory data from plant-mediated transformation of chlorinated and brominated alkanes...alkenes, and chlorinated pesticides, including phytotransformation data from field plants currently used in phytoremediation of trichloroethylene

Three Dimensional Modeling of Agricultural Contamination of Groundwater: a Case Study in the Nebraska Management Systems Evaluation Area (MSEA) Site

NASA Astrophysics Data System (ADS)

Akbariyeh, S.; Snow, D. D.; Bartelt-Hunt, S.; Li, X.; Li, Y.

2015-12-01

Contamination of groundwater from nitrogen fertilizers and pesticides in agricultural lands is an important environmental and water quality management issue. It is well recognized that in agriculturally intensive areas, fertilizers and pesticides may leach through the vadose zone and eventually reach groundwater, impacting future uses of this limited resource. While numerical models are commonly used to simulate fate and transport of agricultural contaminants, few models have been validated based on realistic three dimensional soil lithology, hydrological conditions, and historical changes in groundwater quality. In this work, contamination of groundwater in the Nebraska Management Systems Evaluation Area (MSEA) site was simulated based on extensive field data including (1) lithology from 69 wells and 11 test holes; (2) surface soil type, land use, and surface elevations; (3) 5-year groundwater level and flow velocity; (4) daily meteorological monitoring; (5) 5-year seasonal irrigation records; (6) 5-years of spatially intensive contaminant concentration in 40 multilevel monitoring wells; and (7) detailed cultivation records. Using this data, a three-dimensional vadose zone lithological framework was developed using a commercial software tool (RockworksTM). Based on the interpolated lithology, a hydrological model was developed using HYDRUS-3D to simulate water flow and contaminant transport. The model was validated through comparison of simulated atrazine and nitrate concentration with historical data from 40 wells and multilevel samplers. The validated model will be used to predict potential changes in ground water quality due to agricultural contamination under future climate scenarios in the High Plain Aquifer system.

An analysis of the contrasting fates of locust swarms on the plains of North America and East Asia

NASA Astrophysics Data System (ADS)

Yu, G.; Ke, X.; Shen, H. D.; Li, Y. F.

2013-03-01

Prior to ~1880 AD locust swarms periodically raged across both the North American Plains (NAP) and East Asian Plains (EAP). After this date, locust outbreaks almost never recurred on the NAP but have continued to cause problems on the EAP. The large quantities of pesticides used in the major agriculture regions of the NAP in the late 1870s have been suggested as a possible reason for the disappearance of locust outbreaks in this area. Extensive applications of modern, i.e. more effective, chemical pesticides were also used in the granary regions of the EAP in the 1950s in an effort to reduce pest outbreaks. However, locust swarms returned again in many areas of China in the 1960s. Therefore, locust extinction on the NAP still remains a puzzle. Frequent locust outbreaks on the EAP over the past 130 yr may offer clues to the key factors that control the disappearance of locust outbreaks on the NAP. This study analysed the climate extremes and monthly temperature-precipitation combinations for the NAP and EAP, and found that differences in the frequencies of these climate combinations resulted in the contrasting locust fates in the two regions: restricting locust outbreaks in the NAP but inducing such events in the EAP. Validation shows that severe EAP locust outbreak years were coincidental with extreme climate-combination years. Therefore, we suggest that changes in frequency, extremes and trends in climate can explain why the fate of locust outbreaks in the EAP was different from that in the NAP. The results also suggest that, with present global warming trends, precautionary measures should be taken to make sure other similar pest infestations do not occur in either region.

A~probe into the different fates of locust swarms in the plains of North America and East Asia

NASA Astrophysics Data System (ADS)

Yu, G.; Johnson, D.; Ke, X.; Li, Y.

2012-08-01

Locust swarms had periodically raged in both North American Plains (NAP) and East Asian Plains (EAP) before 1880 AD. After this period, the locust outbreaks almost never recurred in NAP but have continued to occur in EAP. Since large quantities of pesticides were used in the major agriculture regions of NAP in the late 1870s; this has been suggested as a possible major cause of the disappearing of locust outbreaks. Extensive applications of more effective chemical pesticides were also used in the granary regions of EAP in the 1950s in an effort to kill the pests at a much higher intensity. However, locust swarms came back again in many areas of China in the 1960s. Therefore, NAP locust extinction still remains a puzzle. Frequent locust outbreaks in EAP over the past 130 yr may offer clues to probe key control elements in the disappearing of locust outbreaks in NAP. This paper analyzes the climate extremes and monthly temperature-precipitation combines of NAP and EAP, and found the differences in their frequencies of these climate combines caused different locust fates in the two regions: restrained the locust outbreak in NAP but induced such events in EAP. Validation shows that severer EAP locust outbreak years were coincided with the climate extreme combines years. Thus we suggest that climate changes in frequency, extremes and trends can explain why the fate of the locust plague in EAP was different from that in NAP. The study also points out that, under the present global warming, cautions should be taken to make sure the pest hazard being nipped in the-bud.

Light Induced Degradation of Eight Commonly Used Pesticides Adsorbed on Atmospheric Particles: Kinetics and Product Study

NASA Astrophysics Data System (ADS)

Socorro, J.; Durand, A.; Gligorovski, S.; Wortham, H.; Quivet, E.

2014-12-01

Pesticides are widely used all over the world whether in agricultural production or in non-agricultural settings. They may pose a potential human health effects and environmental risks due to their physico-chemical properties and their extensive use which is growing every year. Pesticides are found in the atmosphere removed from the target area by volatilization or wind erosion, and carried over long distances. These compounds are partitioned between the gaseous and particulate atmospheric phases. The increasingly used pesticides are semi-volatile compounds which are usually adsorbed on the surface of the atmospheric particles. These pesticides may undergo chemical and photo-chemical transformation. New compounds may then be formed that could be more hazardous than the primary pesticides. The atmospheric fate and lifetime of adsorbed pesticides on particles are controlled by the these (photo)chemical processes. However, there is a lack of kinetic data regarding the pesticides in the particle phase. This current work focuses on the photolytic degradation of commonly used pesticides in particulate phase. It aims at estimating the photolytic rates and thus the lifetimes of pesticides adsorbed on silica particles as a proxy of atmospheric particles. The following eight commonly used pesticides, cyprodinil, deltamethrin, difenoconazole, fipronil, oxadiazon, pendimethalin, permethrin, tetraconazole, were chosen because of their physico-chemical properties. The photolysis rates of tetraconazole and permethrin were extremely slow ≤ 1.2 · 10-6 s-1. The photolysis rates for the other pesticides were determined in the range of: (5.9 ± 0.3) · 10-6 < k < (1.7 ± 0.1) · 10-4 s-1 from slowest to the fastest: pendimethalin < cyprodinil < deltamethrin < difenoconazole < oxadiazon < fipronil. Finally, the identification of the surface products upon light irradiation was performed, using GC-(QqQ)-MS/MS and LC-(Q-IMS-ToF)-MS/MS. The potentially formed gas-phase products during these photolysis processes were followed continuously and on-line by PTR-ToF-MS. We hope that the obtained results from this study will help in the development of future environmental strategies to better understand and control phyto-sanitary product application and human exposure.

Anticonvulsant Effect of Diazoxide against Dichlorvos-Induced Seizures in Mice

PubMed Central

Jazayeri, Amin; Zolfaghari, Samira; Ostadhadi, Sattar

2013-01-01

Dichlorvos, a synthetic organophosphate toxin, is used as pesticides. These toxins can be used as pesticides in farming and medicine for the devastation and/or elimination of ectoparasites of animals. Reports have shown that Dichlorvos generate seizure effects in various animals. Potassium channel opener is extensively used for medication of cardiovascular and other diseases. Studies have shown that potassium channel opener has anticonvulsant effects in different animal models. The goal of this study was to evaluate the effect of dizoxide on Dichlorvos-induced seizures in mice. In this research, the animals received different doses of Diazoxide (1, 2.5, 5, 10, and 20 mg/kg b.wt.) intraperitoneally 30 min before intraperitoneal injection of Dichlorvos (50 mg/kg b.w.t). After Dichlorvos injection, latency of clones, severity of seizure, and finally death as the fate were investigated. Results showed that Diazoxide dose-dependently decreased the severity of Dichlorvos-induced seizures, so that Diazoxide at a dose of 5 mg (the lowest, P < 0.05) and 20 mg/kg b.wt. (the highest, P < 0.001) has anticonvulsant effects. Thus, our data suggest that diazoxide as ATP-sensitive potassium channels opener has anticonvulsant activity against dichlorvas-induced seizure. PMID:24453891

Fate of pesticides added to the soil in northeast of Santa Fe Province, Argentina.

NASA Astrophysics Data System (ADS)

Vidal, Claudia; Aparicio, Virginia; De Geronimo, Eduardo; Costa, Jose Luis

2017-04-01

The use of pesticides in crop production has increased in the Northeast Santa Fe Province. This region has predominance of argiudolls, hapludalf and natracualf soils, with silt loam texture and 1.5 % of organic matter content. The main crops are sunflower, maize, cotton and sorghum. There are also extensive livestock production systems. The objective of this work was to study the presence and environmental fate of pesticides used in the agricultural systems of the Northeast Santa Fe Province. Different environmental matrices (soil, surface water and sediment) were sampled during the 2014-2015 cropping season in an area of about 180,000 ha of the "Arroyo el Rey" basin. Soil samples were collected at 0-5 cm depth in sunflower, sorghum, soybean and cotton cultivated fields. A total of 12 field plots were sampled, with glyphosate application and without glyphosate application. Water samples were collected at three locations: upper basin, medium basin, and lower basin in polypropylene bottles and stored at -20 °C until analysis. Glyphosate and AMPA was extracted from filtered water samples with a buffer solution (100 mM Na2B4O7•10H2O/100 mM K3PO4, pH=9) and derivatized with 9-fluorenylmethylchloroformate (1 mg mL-1 in acetonitrile). Afterwards samples were analyzed using liquid chromatography coupled to a tandem mass spectrometer (UPLC-MS/MS). A multi-residue determination of pesticides other than glyphosate and AMPA was used to detect pesticides in soil, water and sediment. Hydroxy atrazine (Atz-OH) (a degradation product of atrazine) and AMPA (a degradation product of glyphosate) were founded in the 100% of the soil samples. Below 70% of occurrence frequency were detected molecules such as Imidaclopyr (63%), Glyphosate (63%), Diethyltuolamide (61%), Atrazine (22%), Fluorocloridone (13%), Imazethapyr and Acetochlor To 1%). In water samples taken during 2014 the pesticides that exceeded the threshold of 0.1 μg.L-1 per molecule (European Economic Community) were AMPA (range: 0.7-0.3 μg.L-1), Atrazine (range : 0,201-0,1 μg.L-1), Atz-OH (range: 0.1598-0.135 μg.L-1). Also in some cases, the 0.5 μg.L-1 value (maximum for sum of EEC molecules) was exceeded, with ranges from 0.845 to 0.104 μg.L-1. In the water taken during 2015 the concentrations of AMPA and Glyphosate were greater than in 2014 (ranges: 6,6-0,5 μg.L-1 and 4.5-0,2 μg.L-1, respectively). This preliminary information indicates the need to study processes such as retention, degradation and vertical transport of pesticides to understand the mechanisms by which they are present in the different environmental matrices. In addition, it is important to reduce the input of pesticides added to the environment to produce grains and fibers in this region.

Adsorption of humic acids and trace metals in natural waters

NASA Technical Reports Server (NTRS)

Leung, W. H.

1982-01-01

Studies concerning the interactions between suspended hydrous iron oxide and dissolved humic acids and trace metals are reported. As a major component of dissolved organic matters and its readiness for adsorption at the solid/water interface, humic acids may play a very important role in the organometallic geochemistry of suspended sediments and in determining the fate and distribution of trace metals, pesticides and anions in natural water systems. Most of the solid phases in natural waters contain oxides and hydroxides. The most simple promising theory to describe the interactions of hydrous iron oxide interface is the surface complex formation model. In this model, the adsorptions of humic acids on hydrous iron oxide may be interpreted as complex formation of the organic bases (humic acid oxyanions) with surface Fe ions. Measurements on adsorptions were made in both fresh water and seawater. Attempts have been made to fit our data to Langmuir adsorption isotherm. Adsorption equilibrium constants were determined.

State of research: environmental pathways and food chain transfer.

PubMed Central

Vaughan, B E

1984-01-01

Data on the chemistry of biologically active components of petroleum, synthetic fuel oils, certain metal elements and pesticides provide valuable generic information needed for predicting the long-term fate of buried waste constituents and their likelihood of entering food chains. Components of such complex mixtures partition between solid and solution phases, influencing their mobility, volatility and susceptibility to microbial transformation. Estimating health hazards from indirect exposures to organic chemicals involves an ecosystem's approach to understanding the unique behavior of complex mixtures. Metabolism by microbial organisms fundamentally alters these complex mixtures as they move through food chains. Pathway modeling of organic chemicals must consider the nature and magnitude of food chain transfers to predict biological risk where metabolites may become more toxic than the parent compound. To obtain predictions, major areas are identified where data acquisition is essential to extend our radiological modeling experience to the field of organic chemical contamination. PMID:6428875

Microbiological degradation of pesticides in yard waste composting.

PubMed

Fogarty, A M; Tuovinen, O H

1991-06-01

Changes in public opinion and legislation have led to the general recognition that solid waste treatment practices must be changed. Solid-waste disposal by landfill is becoming increasingly expensive and regulated and no longer represents a long-term option in view of limited land space and environmental problems. Yard waste, a significant component of municipal solid waste, has previously not been separated from the municipal solid-waste stream. The treatment of municipal solid waste including yard waste must urgently be addressed because disposal via landfill will be prohibited by legislation. Separation of yard waste from municipal solid waste will be mandated in many localities, thus stressing the importance of scrutinizing current composting practices in treating grass clippings, leaves, and other yard residues. Yard waste poses a potential environmental health problem as a result of the widespread use of pesticides in lawn and tree care and the persistence of the residues of these chemicals in plant tissue. Yard waste containing pesticides may present a problem due to the recalcitrant and toxic nature of the pesticide molecules. Current composting processes are based on various modifications of either window systems or in-vessel systems. Both types of processes are ultimately dependent on microbial bioconversions of organic material to innocuous end products. The critical stage of the composting process is the thermophilic phase. The fate and mechanism of removal of pesticides in composting processes is largely unknown and in need of comprehensive analysis.

Central San Francisco Bay suspended-sediment transport processes study and comparison of continuous and discrete measurements of suspended-solids concentrations

USGS Publications Warehouse

Schoellhamer, David H.

1994-01-01

Sediments are an important component of the San Francisco Bay estuarine system. Potentially toxic substances, such as metals and pesticides, adsorb to sediment particles. The sediments on the bottom of the Bay provide the habitat for benthic communities which can ingest these substances and introduce them into the food web. The bottom sediments are also a reservoir of nutrients. The transport and fate of suspended sediment is an important factor in determining the transport and fate of the constituents adsorbed on the sediment. Suspended sediments also limit light availability in the bay, which limits photosynthesis and primary production, and deposit in ports and shipping channels, which require dredging. Dredged materials are disposed in Central San Francisco Bay.

Surface-water-quality assessment of the Yakima River basin, Washington; distribution of pesticides and other organic compounds in water, sediment, and aquatic biota, 1987-91; with a section on dissolved organic carbon in the Yakima River basin

USGS Publications Warehouse

Rinella, Joseph F.; McKenzie, Stuart W.; Crawford, J. Kent; Foreman, William T.; Fuhrer, Gregory J.; Morace, Jennifer L.; Aiken, George R.

1999-01-01

During 1987-91, chemical data were collected for pesticides and other organic compounds in surface water, streambed sediment, suspended sediment, agricultural soil, and aquatic biota to determine the occurrence, distribution, transport, and fate of organic compounds in the Yakima River basin in Washington. The report describes the chemical and physical properties of the compounds most frequently detected in the water column; organochlorine compounds including DDT, organophosphorus compounds, thiocarbamate and sulfite compounds, acetamide and triazine compounds, and chlorophenoxy-acetic acid and benzoic compounds. Concentrations are evaluated relative to chronic-toxicity water quality criteria and guidelines for the protection of human health and freshwater aquatic life.

Pesticides in ground water: distribution, trends, and governing factors

USGS Publications Warehouse

Barbash, Jack; Resek, Elizabeth A.

1997-01-01

A comprehensive review of published information on the distribution and behavior of pesticides and their transformation products in ground water indicates that pesticides from every chemical class have been detected in ground waters of the United States. Many of these compounds are commonly present at low concentrations in ground water beneath agricultural land. Little information is available on their occurrence beneath non-agricultural land, although the intensity of their use in such areas (on lawns, golf courses, rights of way, timberlands, etc.) is often comparable to, or greater than agricultural use. Information on pesticides in ground water is not sufficient to provide either a statistically representative view of pesticide occurrence in ground water across the United States, or an indication of long-term trends or changes in the severity or extent of this contamination over the past three decades. This is largely due to wide variations in analytical detection limits, well selection procedures, and other design features among studies conducted in different areas or at different times. Past approaches have not been well suited for distinguishing "point source" from "nonpoint source" pesticide contamination. Among the variety of natural and anthropogenic factors examined, those that appear to be most strongly associated with the intensity of pesticide contamination of ground water are the depth, construction and age of the sampled wells, the amount of recharge (by precipitation or irrigation), and the depth of tillage. Approaches commonly employed for predicting pesticide distributions in the subsurface--including computer simulations, indicator solutes (e.g., nitrate or tritium), and ground-water vulnerability assessments--generally provide unreliable predictions of pesticide occurrence in ground water. Such difficulties may arise largely from a general failure to account for the preferential transport of pesticides in the subsurface. Significant improvements in understanding and predicting the occurrence and fate of pesticides in ground water are likely to depend on: (1) greater coordination of ground-water sampling across the nation to ensure consistency of study design, and thus comparability of results; (2) more extensive analyses for pesticide transformation products during ground-water monitoring studies; (3) substantially enhanced communication among investigators conducting laboratory experiments, small-scale field studies and large-scale monitoring studies; and (4) more routine testing of predictions of pesticide behavior and ground-water vulnerability against actual field observations of pesticide occurrence in ground water

Modeling fungicides mobility in undisturbed vineyard soil cores unamended and amended with spent mushroom substrates.

PubMed

Marín-Benito, Jesús María; Rodríguez-Cruz, María Sonia; Sánchez-Martín, María Jesús; Mamy, Laure

2015-09-01

The performance of the pesticide fate model PRZM to predict the fate of two fungicides, penconazole and metalaxyl, and the major metabolite of metalaxyl (CGA-62826), in amended and unamended vineyard soils was tested from undisturbed soils columns experiments. Three different treatments were tested in two soils: control soil (unamended), and soil amended with fresh or composted spent mushroom substrates, which correspond to common agricultural practices in Spain. Leaching experiments were performed under non-saturated flow conditions. The model was parameterized with laboratory and literature data, and using pedotransfer functions. It was first calibrated for water flow against chloride breakthrough curves. The key parameter was the hydrodynamic dispersion coefficient (DISP). No leaching of penconazole, the most hydrophobic fungicide, was observed. It remained in the top 0-8 cm of the column. In any case, simulations were highly correlated to the experimental results. On the contrary, metalaxyl and its metabolite were consistently found in the leachates. A calibration step of the Kd of metalaxyl and CGA-62826 and of DISP for CGA-62826 was necessary to obtain good prediction of the leaching of both compounds. PRZM generally simulated acceptable metalaxyl vertical distribution in the soil profiles although results were overestimated for its metabolite. Nevertheless, PRZM can be reasonably used to assess the leaching (through breakthrough curves) and vertical distribution of fungicides in amended soils, knowing their DISP values. Copyright © 2015 Elsevier Ltd. All rights reserved.

Degradation of Nicotine in Chlorinated Water: Pathways and ...

EPA Pesticide Factsheets

Report The objective of the study is to illustrate how drinking water would affect alkaloid pesticides, and to address the issue by (a) investigating the fate of nicotine in chlorinated drinking water and deionized water, (b) determining the reaction rate and pathway of the reaction between nicotine and aqueous chlorine, (c) identifying nicotine’s degradation products, and (d) providing data that can be used to assess the potential threat from nicotine in drinking water.

Studies by the U.S. Geological Survey on sources, transport, and fate of agricultural chemicals

USGS Publications Warehouse

Capel, Paul D.; Hamilton, Pixie A.; Erwin, Martha L.

2004-01-01

Information from these studies will help with decision-making related to chemical use, conservation, and other farming practices that are used to reduce runoff of agricultural chemicals and sediment from fields. This information also will benefit the U.S. Environmental Protection Agency, the Department of Agriculture, local and regional water managers, and agricultural chemical manufacturers who are involved in managing chemical use and pesticide registration.

Measuring and Modeling Solute Transport in the Rootzone: Protecting the Receiving Water Environments of the Coral Atolls of Tonga

NASA Astrophysics Data System (ADS)

Clothier, B. E.; van der Velde, M.; Green, S. R.; Gee, G. W.; Manu, V.; Menoniti, V.; Vanclooster, M.

2005-05-01

Intensification of agriculture on the raised coral atolls of the Tongan archipelago, notably through squash-pumpkin production, has lead to increased use of agrichemicals. Agrichemicals, both fertilisers and pesticides, pose a risk to these fragile environments. Sustainable land-management practices are needed for small-island developing states. On Tongatapu, solutes leaving the rootzone of the squash can rapidly find their way to the underlying freshwater lenses. These lenses are hydraulically linked to the internal lagoon, and the fringing reefs. We have used buried, non-suction fluxmeters to monitor both the quantity and quality of drainage leaving the rootzone of squash. Fertiliser is traditionally applied at planting. During establishment of the squash in 2003, some 350 mm of rain fell, with 70 % of this leaving the rootzone of this permeable soil as drainage. The concentration of nitrate-N in the drainage water was measured at around 50 mg-N/L. All of the initial fertiliser dressing had been lost, along with N mineralised from the plowed-in grass. Pesticides are needed in humid tropical environments to control weeds, pests and diseases. These chemicals can leach though the rootzone to contaminate receiving waters. We modeled the transport and fate of the presticides used in squash production, and we developed a Decision Support Tool (DST). Our DST can be used to select the best pesticides for local conditions, to tailor practices for minimising leaching losses below the rootzone, and to avoid the build-up of residues in the soil. This project, funded by the European Union and NZAID, took a multi-disciplinary approach through measurement and modeling protocols. Our DST enabled us to engage the wider community and stakeholders. There has been increased awareness of the impacts and risks associated with productive land management in the fragile hydrological environments of this small-island developing state.

Simulation of stream discharge and transport of nitrate and selected herbicides in the Mississippi River Basin

USGS Publications Warehouse

Broshears, R.E.; Clark, G.M.; Jobson, H.E.

2001-01-01

Stream discharge and the transport of nitrate, atrazine, and metolachlor in the Mississippi River Basin were simulated using the DAFLOW/BLTM hydrologic model. The simulated domain for stream discharge included river reaches downstream from the following stations in the National Stream Quality Accounting Network: Mississippi River at Clinton, IA; Missouri River at Hermann, MO: Ohio River at Grand Chain, IL: And Arkansas River at Little Rock, AR. Coefficients of hydraulic geometry were calibrated using data from water year 1996; the model was validated by favourable simulation of observed discharges in water years 1992-1994. The transport of nitrate, atrazine, and metolachlor was simulated downstream from the Mississippi River at Thebes, IL, and the Ohio River at Grand Chain. Simulated concentrations compared favourably with observed concentrations at Baton Rouge, LA. Development of this model is a preliminary step in gaining a more quantitative understanding of the sources and fate of nutrients and pesticides delivered from the Mississippi River Basin to the Gulf of Mexico.

Pesticide exposure assessment for surface waters in the EU. Part 2: Determination of statistically based run-off and drainage scenarios for Germany.

PubMed

Bach, Martin; Diesner, Mirjam; Großmann, Dietlinde; Guerniche, Djamal; Hommen, Udo; Klein, Michael; Kubiak, Roland; Müller, Alexandra; Preuss, Thomas G; Priegnitz, Jan; Reichenberger, Stefan; Thomas, Kai; Trapp, Matthias

2017-05-01

In order to assess surface water exposure to active substances of plant protection products (PPPs) in the European Union (EU), the FOCUS (FOrum for the Co-ordination of pesticide fate models and their USe) surface water workgroup introduced four run-off and six drainage scenarios for Step 3 of the tiered FOCUSsw approach. These scenarios may not necessarily represent realistic worst-case situations for the different Member States of the EU. Hence, the suitability of the scenarios for risk assessment in the national authorisation procedures is not known. Using Germany as an example, the paper illustrates how national soil-climate scenarios can be developed to model entries of active substances into surface waters from run-off and erosion (using the model PRZM) and from drainage (using the model MACRO). In the authorisation procedure for PPPs on Member State level, such soil-climate scenarios can be used to determine exposure endpoints with a defined overall percentile. The approach allows the development of national specific soil-climate scenarios and to calculate percentile-based exposure endpoints. The scenarios have been integrated into a software tool analogous to FOCUS-SWASH which can be used in the future to assess surface water exposure in authorisation procedures of PPPs in Germany. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Accelerated biodegradation of selected nematicides in tropical crop soils from Costa Rica.

PubMed

Chin-Pampillo, Juan Salvador; Carazo-Rojas, Elizabeth; Pérez-Rojas, Greivin; Castro-Gutiérrez, Víctor; Rodríguez-Rodríguez, Carlos E

2015-01-01

Degradation and mineralization behavior of selected nematicides was studied in soil samples from fields cultivated with banana, potato, and coffee. Degradation assays in most of the studied soils revealed shorter half-lives for carbofuran (CBF) and ethoprophos (ETP) in samples with a history of treatment with these compounds, which may have been caused by enhanced biodegradation. A short half-life value for CBF degradation was also observed in a banana field with no previous exposure to this pesticide, but with a recent application of the carbamate insecticide oxamyl, which supports the hypothesis that preexposure to oxamyl may cause microbial adaptation towards degradation of CBF, an observation of a phenomenon not yet tested according to the literature reviewed. Mineralization assays for CBF and terbufos (TBF) revealed that history of treatment with these nematicides did not cause higher mineralization rates in preexposed soils when compared to unexposed ones, except in the case of soils from coffee fields. Mineralization half-lives for soils unexposed to these pesticides were significantly shorter than most reports in the literature in the same conditions. Mineralization rates for soils with a previous exposure to these pesticides were also obtained, adding to the very few reports found. This paper contributes valuable data to the low number of reports dealing with pesticide fate in soils from tropical origin.

Fate of selected pesticides, estrogens, progestogens and volatile organic compounds during artificial aquifer recharge using surface waters.

PubMed

Kuster, Marina; Díaz-Cruz, Silvia; Rosell, Mònica; López de Alda, Miren; Barceló, Damià

2010-05-01

The artificial recharge of aquifers has become a valuable tool to increase water resources for drinking water production in many countries. In this work a total of 41 organic pollutants belonging to the classes of pesticides, estrogens, progestogens and volatile organic compounds (VOCs) have been monitored in the water from two artificial recharge plants located in Sweden and Denmark. The results from two sampling campaigns performed in each plant indicate good chemical status of the source water, as the contaminants detected were present at very low levels, far from those established in the legislation as maximum admissible concentrations (when existing) and far from those considered as a risk. Thus, of the 17 pesticides investigated, BAM (2,6-dichlorobenzamide), desethylatrazine, simazine, atrazine, terbuthylazine, diuron, metolachlor, and diazinon were the only compounds detected, and total pesticides levels were below 25ng L(-1), respectively. Estrone-3-sulfate was the only estrogen detected, at concentrations lower than 0.5ng L(-1). Progestogens were not found in any sample. Detected VOCs (benzene, toluene, ethylbenzene, and trichloroethylene) were below 0.04microg L(-1). The efficiency of elimination of these organic contaminants was poor as no significant decrease in their concentrations was observed through the recharge process.

Heterogeneous oxidation of pesticides on aerosol condensed phase

NASA Astrophysics Data System (ADS)

Socorro, Joanna; Durand, Amandine; Temime-Roussel, Brice; Ravier, Sylvain; Gligorovski, Sasho; Wortham, Henri; Quivet, Etienne

2015-04-01

Pesticides are widely used all over the world. It is known that they exhibit adverse health effects and environmental risks due to their physico-chemical properties and their extensive use which is growing every year. They are distributed in the atmosphere, an important vector of dissemination, over long distances away from the target area. The partitioning of pesticides between the gas and particulate phases influences their atmospheric fate. Most of the pesticides are semi-volatile compounds, emphasizing the importance of assessing their heterogeneous reactivity towards atmospheric oxidants. These reactions are important because they are involved in, among others, direct and indirect climate changes, adverse health effects from inhaled particles, effects on cloud chemistry and ozone production. In this work, the importance of atmospheric degradation of pesticides is evaluated on the surface of aerosol deliquescent particles. The photolysis processing and heterogeneous reactivity towards O3 and OH, was evaluated of eight commonly used pesticides (cyprodinil, deltamethrin, difenoconazole, fipronil, oxadiazon, pendimethalin, permethrin, tetraconazole) adsorbed on silica particles. Silicate particles are present in air-borne mineral dust in atmospheric aerosols, and heterogeneous reactions can be different in the presence of these mineral particles. Depending on their origin and conditioning, aerosol particles containing pesticides can have complex and highly porous microstructures, which are influenced by electric charge effects and interaction with water vapour. Therefore, the kinetic experiments and consecutive product studies were performed at atmospherically relevant relative humidity (RH) of 55 %. The identification of surface bound products was performed using GC-(QqQ)-MS/MS and LC-(Q-ToF)-MS/MS and the gas-phase products were on-line monitored by PTR-ToF-MS. Based on the detected and identified reaction products, it was observed that water plays a crucial role in the reaction mechanism of ozone and hydroxyl radical with the adsorbed pesticides on the silica particles. The obtained results will allow better understanding of the impact of pesticides and their degradation products on human health, and to make recommendations in order to reduce population exposure to the pesticide plume and the pollution by phyto-sanitary products on the regional scale, which constitutes a necessary step in the development of environmental strategies.

A comparison of the fate and effects of two pyrethroid insecticides (lambda-cyhalothrin and cypermethrin) in pond mesocosms.

PubMed

Farmer, D; Hill, I R; Maund, S J

1995-08-01

: The fate and effects of two pyrethroid insecticides (lambda-cyhalothrin and cypermethrin) were investigated in replicated 25 m(3) pond mesocosms. Three pesticide treatments which simulated spray drift deposition were examined: 0.7 g a.i. ha(-1) cypermethrin and 0.17 and 1.7 g a.i. ha(-1) lambda-cyhalothrin. Based on the use rate and pesticidal activity of the chemicals, the cypermethrin and lower lambda-cyhalothrin rates were approximately equivalent. After applications, pyrethroid residues in the water column declined rapidly. Treatment-related effects were observed on some macroinvertebrate taxa, most notably the Asellidae and Gammaridae. Surfacedwelling insects also suffered initial knock-down, particularly in the 1.7 g a.i. ha(-1) lambda-cyhalothrin treatment, but there was recovery after the spray period. No adverse effects occurred on algae, macrophytes or zooplankton, but there were occasional enhancements (e.g. algal biomass and abundances of copepod nauplii and Rotifera) which may have been indirect effects. An overall comparison of the treatments indicated that the higher lambda-cyhalothrin rate had the greatest effects, whilst the cypermethrin application had a somewhat greater impact than the lower lambda-cyhalothrin treatment rate (due to effects on peracarid crustaceans). The study indicated that should spray drift occur at the levels expected for either pyrethroid's normal use patterns, potential impacts on natural aquatic ecosystems would be minor and transient.

Analysis of pesticides in surface water and sediment from Yolo Bypass, California, 2004-2005

USGS Publications Warehouse

Smalling, Kelly L.; Orlando, James L.; Kuivila, Kathryn

2005-01-01

Inputs to the Yolo Bypass are potential sources of pesticides that could impact critical life stages of native fish. To assess the direct inputs during inundation, pesticide concentrations were analyzed in water, in suspended and bed-sediment samples collected from six source watersheds to the Yolo Bypass, and from three sites within the Bypass in 2004 and 2005. Water samples were collected in February 2004 from the six input sites to the Bypass during the first flood event of the year representing pesticide inputs during high-flow events. Samples were also collected along a transect across the Bypass in early March 2004 and from three sites within the Bypass in the spring of 2004 under low-flow conditions. Low-flow data were used to understand potential pesticide contamination and its effects on native fish if water from these areas were used to flood the Bypass in dry years. To assess loads of pesticides to the Bypass associated with suspended sediments, large-volume water samples were collected during high flows in 2004 and 2005 from three sites, whereas bed sediments were collected from six sites in the fall of 2004 during the dry season. Thirteen current-use pesticides were detected in surface water samples collected during the study. The highest pesticide concentrations detected at the input sites to the Bypass corresponded to the first high-flow event of the year. The highest pesticide concentrations at the two sites sampled within the Bypass during the early spring were detected in mid-April following a major flood event as the water began to subside. The pesticides detected and their concentrations in the surface waters varied by site; however, hexazinone and simazine were detected at all sites and at some of the highest concentrations. Thirteen current-use pesticides and three organochlorine insecticides were detected in bed and suspended sediments collected in 2004 and 2005. The pesticides detected and their concentrations varied by site and sediment sample type. Trifluralin, p,p'-DDE, and p,p'-DDT were highest in the bed sediments, whereas oxyfluorfen and thiobencarb were highest in the suspended sediments. With the exception of the three organochlorine insecticides, suspended sediments had higher pesticide concentrations compared with bed sediments, indicating the potential for pesticide transport throughout the Bypass, especially during high-flow events. Understanding the distribution of pesticides between the water and sediment is needed to assess fate and transport within the Bypass and to evaluate the potential effects on native fish.

Simulation of branched serial first-order decay of atrazine and metabolites in adapted and nonadapted soils

USGS Publications Warehouse

Webb, R.M.; Sandstrom, M.W.; Krutz, L.J.; Shaner, D.L.

2011-01-01

In the present study a branched serial first-order decay (BSFOD) model is presented and used to derive transformation rates describing the decay of a common herbicide, atrazine, and its metabolites observed in unsaturated soils adapted to previous atrazine applications and in soils with no history of atrazine applications. Calibration of BSFOD models for soils throughout the country can reduce the uncertainty, relative to that of traditional models, in predicting the fate and transport of pesticides and their metabolites and thus support improved agricultural management schemes for reducing threats to the environment. Results from application of the BSFOD model to better understand the degradation of atrazine supports two previously reported conclusions: atrazine (6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine) and its primary metabolites are less persistent in adapted soils than in nonadapted soils; and hydroxyatrazine was the dominant primary metabolite in most of the soils tested. In addition, a method to simulate BSFOD in a one-dimensional solute-transport unsaturated zone model is also presented. ?? 2011 SETAC.

Simulation of branched serial first-order decay of atrazine and metabolites in adapted and nonadapted soils

USGS Publications Warehouse

Webb, Richard M.; Sandstrom, Mark W.; Jason L. Krutz,; Dale L. Shaner,

2011-01-01

In the present study a branched serial first-order decay (BSFOD) model is presented and used to derive transformation rates describing the decay of a common herbicide, atrazine, and its metabolites observed in unsaturated soils adapted to previous atrazine applications and in soils with no history of atrazine applications. Calibration of BSFOD models for soils throughout the country can reduce the uncertainty, relative to that of traditional models, in predicting the fate and transport of pesticides and their metabolites and thus support improved agricultural management schemes for reducing threats to the environment. Results from application of the BSFOD model to better understand the degradation of atrazine supports two previously reported conclusions: atrazine (6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine) and its primary metabolites are less persistent in adapted soils than in nonadapted soils; and hydroxyatrazine was the dominant primary metabolite in most of the soils tested. In addition, a method to simulate BSFOD in a one-dimensional solute-transport unsaturated zone model is also presented.

Use of mesocosm data to predict effects in aquatic ecosystems: Limits to interpretation: Chapter 16

USGS Publications Warehouse

La Point, Thomas W.; Fairchild, James F.; Graney, Robert L.; Kennedy, James H.; Rodgers, John H.

1993-01-01

Aquatic mesocosm studies are being used to refute a presumption of risk derived from laboratory toxicity tests conducted under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). Mesocosm studies incorporate many biological, chemical and physical characteristics of natural ecosystems. Hence, they serve as realistic surrogates of natural ecosystems and allow tests of pesticide effect at the population, community, and ecosystem level. We discuss two factors, ecosystem trophic status and organism life history, which influence the results derived from aquatic mesocosm studies.  Trophic status influences the fat and effects of chemicals which strongly sorb or biologically degrade, yet may not be as important in the fate and effects of more water soluble chemicals.  Life history traits of organisms and the intensity, frequency, and duration of the pesticide disturbance also determine the mesocosm response pattern.

Pesticide bioconcentration modelling for fruit trees.

PubMed

Paraíba, Lourival Costa

2007-01-01

The model presented allows simulating the pesticide concentration evolution in fruit trees and estimating the pesticide bioconcentration factor in fruits. Pesticides are non-ionic organic compounds that are degraded in soils cropped with woody species, fruit trees and other perennials. The model allows estimating the pesticide uptake by plants through the water transpiration stream and also the time in which maximum pesticide concentration occur in the fruits. The equation proposed presents the relationships between bioconcentration factor (BCF) and the following variables: plant water transpiration volume (Q), pesticide transpiration stream concentration factor (TSCF), pesticide stem-water partition coefficient (K(Wood,W)), stem dry biomass (M) and pesticide dissipation rate in the soil-plant system (k(EGS)). The modeling started and was developed from a previous model "Fruit Tree Model" (FTM), reported by Trapp and collaborators in 2003, to which was added the hypothesis that the pesticide degradation in the soil follows a first order kinetic equation. The FTM model for pesticides (FTM-p) was applied to a hypothetic mango plant cropping (Mangifera indica) treated with paclobutrazol (growth regulator) added to the soil. The model fitness was evaluated through the sensitivity analysis of the pesticide BCF values in fruits with respect to the model entry data variability.

Simulating pesticide transport in urbanized catchments: a new spatially-distributed dynamic pesticide runoff model

NASA Astrophysics Data System (ADS)

Tang, Ting; Seuntjens, Piet; van Griensven, Ann; Bronders, Jan

2016-04-01

Urban areas can significantly contribute to pesticide contamination in surface water. However, pesticide behaviours in urban areas, particularly on hard surfaces, are far less studied than those in agricultural areas. Pesticide application on hard surfaces (e.g. roadsides and walkways) is of particular concern due to the high imperviousness and therefore high pesticide runoff potential. Experimental studies have shown that pesticide behaviours on and interactions with hard surfaces are important factors controlling the pesticide runoff potential, and therefore the magnitude and timing of peak concentrations in surface water. We conceptualized pesticide behaviours on hard surfaces and incorporated the conceptualization into a new pesticide runoff model. The pesticide runoff model was implemented in a catchment hydrological model WetSpa-Python (Water and Energy Transfer between Soil, Plants and Atmosphere, Python version). The conceptualization for pesticide processes on hard surfaces accounts for the differences in pesticide behaviour on different hard surfaces. Four parameters are used to describe the partitioning and wash-off of each pesticide on hard surfaces. We tested the conceptualization using experimental dataset for five pesticides on two types of hard surfaces, namely concrete and asphalt. The conceptualization gave good performance in accounting for the wash-off pattern for the modelled pesticides and surfaces, according to quantitative evaluations using the Nash-Sutcliffe efficiency and percent bias. The resulting pesticide runoff model WetSpa-PST (WetSpa for PeSTicides) can simulate pesticides and their metabolites at the catchment scale. Overall, it includes four groups of pesticide processes, namely pesticide application, pesticide interception by plant foliage, pesticide processes on land surfaces (including partitioning, degradation and wash-off on hard surface; partitioning, dissipation, infiltration and runoff in soil) and pesticide processes in depression storage (including degradation, infiltration and runoff). Processes on hard surfaces employs the conceptualization described in the paragraph above. The WetSpa-PST model can account for various spatial details of the urban features in a catchment, such as asphalt, concrete and roof areas. The distributed feature also allows users to input detailed pesticide application data of both non-point and point origins. Thanks to the Python modelling framework prototype used in the WetSpa-Python model, processes in the WetSpa-PST model can be simulated at different time steps depending on data availability and the characteristic temporal scale of each process. This helps to increase the computational accuracy during heavy rainfall events, especially for the associated fast transport of pesticides into surface water. Overall, the WetSpa-PST model has good potential in predicting effects of management options on pesticide releases from heavily urbanized catchments.

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

PubMed

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

2017-08-01

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

Concentration levels of new-generation fungicides in throughfall released by foliar wash-off from vineyards.

PubMed

Pérez-Rodríguez, P; Soto-Gómez, D; Paradelo, M; López-Periago, J E

2017-12-01

The presence of agricultural pesticides in the environment and their effects on ecosystems are major concerns addressed in a significant number of articles. However, limited information is available on the pesticide concentrations released from crops. This study reports losses of new-generation fungicides by foliar wash-off from vineyards and their potential impact on the concentrations of their main active substances (AS) in surface waters. Two experimental plots devoted to vineyards were treated with various combinations of commercial new-generation fungicide formulations. Then, up to sixteen throughfall collectors were installed under the canopy. Concentrations of sixteen different AS in throughfall were determined along nine rainfall episodes. Concentrations in throughfall far exceeded the maximum permissible levels for drinking water established by the European Union regulations. Dynamics of fungicide release indicated a first-flush effect in the wash-off founding the highest concentrations of AS in the first rain episodes after application of the fungicides. This article shows that foliar spray application of commercial formulations of new-generation fungicides does not prevent the release of their AS to soil or the runoff. Concentration data obtained in this research can be valuable in supporting the assessment of environmental effects of new-generation fungicides and modeling their environmental fate. Copyright © 2017 Elsevier Ltd. All rights reserved.

Quantification of pesticides used in agriculture in the EU-27

NASA Astrophysics Data System (ADS)

Wagner, Susanne; Fantke, Peter; Theloke, Jochen; Friedrich, Rainer

2010-05-01

Pesticides have become relatively ubiquitous pollutants. They may affect non-targeted organisms and can be found as contaminants in agricultural soils, groundwater, rivers, lakes and in the food chain (Margni et al., 2002; Hamilton & Crossley, 2004; Arias-Estévez et al., 2008). As "it has been common knowledge that many pesticides cause harm to the environment and to human health" (Pretty & Waibel, 2005), it is essential to account for a quantitative assessment of impacts of current agricultural practice at the European scale. Therefore, inventory data sets of applications and related emissions of the most relevant active substances are necessary. A review of publicly available data sets evidenced that data on consumption of active substances and releases into the environment for EU member states are of low quality or lacking entirely. Either only few substances are covered (e.g. EPER, E-PRTR) or data are highly aggregated in terms of total amount of active substances. Sales or consumption data are differentiated by target organisms and crop types (Eurostat) or by chemical classes (FAOSTAT, OECD.StatExtracts). In Germany, sales data categorised into target organisms and chemical classes are available. To our knowledge, Denmark and the United Kingdom are the only European countries providing application rates for specific active substances and crops. As a basis for analysing the relation between source, environmental fate and sink of pesticides and for considering the importance of crop-specific properties on the fate of pesticides (Trapp and Kulhanek, 2006), crop-specific emission inventories for individual active substances are required. Thus, the aim of our work was to develop a crop-specific inventory for active substances currently used in agriculture in the EU-27. Based on Eurostat (2007), the five most important active substances applied to the crop categories of cereals, maize, oilseeds, potatoes, sugar-beets, grapes and vine, fruit trees and vegetables were identified for each EU member state. The focus was on herbicides and insecticides. Also, the average dosage (i.e. application rate [kg active substance/ha]) for chemical classes per crop category and country was provided. Each active substance was then related to the average dosage of its chemical class for each crop category and country. The amount of active substance applied on a specific crop type in a country was calculated by multiplying the country specific crop production area with the respective dosage. Based on the loss fraction of applied substance to air, the emission into air can be calculated. With this approach we identified 89 active substances of relevance (63 herbicides, 26 insecticides) in the EU-27. The analysis showed a high variation of active substances between the member states, i.e. each country uses particular herbicides and insecticides for particular commodities according to specific climate conditions. For the majority of the member states, our approach covers more than 70 % of total use compared to the aggregated consumption of active substances per country as published in Eurostat. For some specific countries with substance-specific application data available, our results can be compared to real application rates. Discrepancies can be considered as an indicator for the variation of our estimates. By relating the emission inventory data sets to land use maps, they can be spatially disaggregated and thus may serve as input for a subsequent exposure and impact assessment modelling of individual pesticides. References: Arias-Estévez, M., López-Periago, E., Martínez-Carballo, E., Simal-Gándara, J., Mejuto, J.-C., García-Río, L. (2008). The mobility and degradation of pesticides in soils and the pollution of groundwater resources. Agriculture, Ecosystems and Environment 123(4): 247-260. EPER. The European Pollutant Emission Register. Available online at: http://www.eper.ec.europa.eu/. E-PRTR. The European Pollutant Release and Transfer Register. Available online at: http://prtr.ec.europa.eu/. Eurostat (2007). The use of plant protection products in the European Union. Data 1992-2003. Eurostat Statistical books, 2007 edition. Eurostat. Pesticides consumption and sales data. Available online at: http://epp.eurostat.ec.europa.eu/portal/page/portal/environment/data/database. FAOSTAT. Pesticides Consumption Data. Available online at: http://faostat.fao.org/site/424/default.aspx. Hamilton, D. and S. Crossley (2004). Pesticide Residues in Food and Drinking Water: Human Exposure and Risks. Chichester, John Wiley & Sons. Margni, M., Jolliet, O., Rossier, D., Crettaz, P. (2002). Life cycle impact assessment of pesticides on human health and ecosystems. Agriculture, Ecosystems and Environment 93: 379-392. OECD.StatExtracts. Pesticides use data. Available online at: http://stats.oecd.org/Index.aspx. Pretty, J.N., H. Waibel (2005). Paying the price: the full cost of pesticides. In: Pretty, J.N. (Ed.) The Pesticide Detox. London, Earthscan, pp. 39-54. Trapp, S., A. Kulhanek (2006). Human Exposure Assessment for Food - One Equation for all Crops is not enough. In: Mackova, M., D. Dowling, T. Macek. Phytoremediation and Rhizoremediation. Dordrecht, The Netherlands, Springer Press: 285-300.

Occurrence and Transport of Agricultural Chemicals in Leary Weber Ditch Basin, Hancock County, Indiana, 2003-04

USGS Publications Warehouse

Baker, Nancy T.; Stone, Wesley W.; Wilson, John T.; Meyer, Michael T.

2006-01-01

Leary Weber Ditch Basin, Hancock County, Indiana, is one of seven first-order basins selected from across the United States as part of the Agricultural Chemicals: Source, Transport, and Fate study conducted by the National Water-Quality Assessment Program of the U.S. Geological Survey. The nationwide study was designed to increase the understanding of the links between the sources of water and agricultural chemicals (nutrients and pesticides) and the transport and fate of these chemicals through the environment. Agricultural chemicals were detected in Leary Weber Ditch and in every associated hydrologic compartment sampled during 2003 and 2004. Pesticides were detected more frequently in samples collected from overland flow and from the ditch itself and less frequently in ground-water samples. The lowest concentrations of pesticides and nutrients were detected in samples of rain, soil water, and ground water. The highest concentrations of pesticides and nutrients were detected in samples of tile-drain water, overland flow, and water from Leary Weber Ditch. Samples collected from the tile drain, overland flow and Leary Weber Ditch soon after chemical applications to the fields and coincident with rainfall and increased streamflow had higher concentrations of pesticides and nutrients than samples collected a longer time after the chemicals were applied. A mass-balance mixing analysis based on potassium concentrations indicated that tile drains are the primary contributor of water to Leary Weber Ditch, but overland flow is also an important contributor during periods of high-intensity rainfall. When maximum rainfall intensity was 0.5 inches per hour or lower, overland flow contributed about 10 percent and tile drains contributed about 90 percent of the flow to Leary Weber Ditch. When maximum rainfall intensity was 0.75 inches per hour or greater, overland flow contributed about 40 percent and tile drains contributed about 60 percent of the flow to the ditch. Ground-water flow to Leary Weber Ditch was negligible. Tile drains are an important agricultural-chemical transport path to Leary Weber Ditch, based on the hydrologic contributions of overland flow and tile drains to the ditch. Overland flow is also an important agricultural-chemical transport pathway during high-intensity rainfall; however, storms with high-intensity rainfall are sporadic throughout the year. Tile drains and the soil water moving to the tile drains are the primary transport pathway for agricultural-chemical transport to Leary Weber Ditch during most storms as well as between storms.

Pesticides in Ground Water of the Maryland Coastal Plain

USGS Publications Warehouse

Denver, Judith M.; Ator, Scott W.

2006-01-01

Selected pesticides are detectable at low levels (generally less than 0.1 microgram per liter) in unconfined ground water in many parts of the Maryland Coastal Plain. Samples were recently collected (2001-04) from 47 wells in the Coastal Plain and analyzed for selected pesticides and degradate compounds (products of pesticide degradation). Most pesticide degradation occurs in the soil zone before infiltration to the water table, and degradates of selected pesticides were commonly detected in ground water, often at higher concentrations than their respective parent compounds. Pesticides and their degradates often occur in ground water in mixtures of multiple compounds, reflecting similar patterns in usage. All measured concentrations in ground water were below established standards for drinking water, and nearly all were below other health-based guidelines. Although drinking-water standards and guidelines are typically much higher than observed concentrations in ground water, they do not exist for many detected compounds (particularly degradates), or for mixtures of multiple compounds. The distribution of observed pesticide compounds reflects known usage patterns, as well as chemical properties and environmental factors that affect the fate and transport of these compounds in the environment. Many commonly used pesticides, such as glyphosate, pendimethalin, and 2,4-D were not detected in ground water, likely because they were sorbed onto organic matter or degraded in the soil zone. Others that are more soluble and (or) persistent, like atrazine, metolachlor, and several of their degradates, were commonly detected in ground water where they have been used. Atrazine, for example, an herbicide used primarily on corn, was most commonly detected in ground water on the Eastern Shore (where agriculture is common), particularly where soils are well drained. Conversely, dieldrin, an insecticide previously used heavily for termite control, was detected only on the Western Shore, where urban land is more common. Use of dieldrin was suspended in 1987, but this compound is relatively persistent in the environment, and several decades are typically required for ground water to move completely through the surficial aquifer. U.S. Department of the Interior U.S. Geological Survey USGS Fact Sheet FS 2006-3119 2006 Location of the Maryland Coastal Plain.

Development and validation of a physiology-based model for the prediction of pharmacokinetics/toxicokinetics in rabbits

PubMed Central

Hermes, Helen E.; Teutonico, Donato; Preuss, Thomas G.; Schneckener, Sebastian

2018-01-01

The environmental fates of pharmaceuticals and the effects of crop protection products on non-target species are subjects that are undergoing intense review. Since measuring the concentrations and effects of xenobiotics on all affected species under all conceivable scenarios is not feasible, standard laboratory animals such as rabbits are tested, and the observed adverse effects are translated to focal species for environmental risk assessments. In that respect, mathematical modelling is becoming increasingly important for evaluating the consequences of pesticides in untested scenarios. In particular, physiologically based pharmacokinetic/toxicokinetic (PBPK/TK) modelling is a well-established methodology used to predict tissue concentrations based on the absorption, distribution, metabolism and excretion of drugs and toxicants. In the present work, a rabbit PBPK/TK model is developed and evaluated with data available from the literature. The model predictions include scenarios of both intravenous (i.v.) and oral (p.o.) administration of small and large compounds. The presented rabbit PBPK/TK model predicts the pharmacokinetics (Cmax, AUC) of the tested compounds with an average 1.7-fold error. This result indicates a good predictive capacity of the model, which enables its use for risk assessment modelling and simulations. PMID:29561908

Narrow pH Range of Surface Water Bodies Receiving Pesticide Input in Europe.

PubMed

Bundschuh, Mirco; Weyers, Arnd; Ebeling, Markus; Elsaesser, David; Schulz, Ralf

2016-01-01

Fate and toxicity of the active ingredients (AI's) of plant protection products in surface waters is often influenced by pH. Although a general range of pH values is reported in literature, an evaluation targeting aquatic ecosystems with documented AI inputs is lacking at the larger scale. Results show 95% of European surface waters (n = 3075) with a documented history of AI exposure fall within a rather narrow pH range, between 7.0 and 8.5. Spatial and temporal variability in the data may at least be partly explained by the calcareous characteristics of parental rock material, the affiliation of the sampling site to a freshwater ecoregion, and the photosynthetic activity of macrophytes (i.e., higher pH values with photosynthesis). Nonetheless, the documented pH range fits well with the standard pH of most ecotoxicological test guidelines, confirming the fate and ecotoxicity of AIs are usually adequately addressed.

Fate of organohalogens in US wastewater treatment plants and estimated chemical releases to soils nationwide from biosolids recycling.

PubMed

Heidler, Jochen; Halden, Rolf U

2009-12-01

This study examined the occurrence in wastewater of 11 aromatic biocides, pesticides and degradates, and their fate during passage through US treatment plants, as well as the chemical mass contained in sewage sludge (biosolids) destined for land application. Analyte concentrations in wastewater influent, effluent and sludge from 25 facilities in 18 US states were determined by liquid chromatography electrospray (tandem) mass spectrometry. Dichlorocarbanilide, fipronil, triclocarban, and triclosan were found consistently in all sample types. Dichlorophene, hexachlorophene, and tetrachlorocarbanilide were detected infrequently only, and concentrations of the phenyl urea pesticides diflubenzuron, hexaflumuron, and linuron were below the limit of detection in all matrixes. Median concentrations (+/-95% confidence interval) of quantifiable compounds in influent ranged from 4.2 +/- 0.8 microg L(-1) for triclocarban to 0.03 +/- 0.01 microg L(-1) for fipronil. Median concentrations in effluent were highest for triclocarban and triclosan (0.23 +/- 0.08 and 0.07 +/- 0.04 microg L(-1), respectively). Median aqueous-phase removal efficiencies (+/-95% CI) of activated sludge treatment plants decreased in the order of: triclosan (96 +/- 2%) > triclocarban (87 +/- 7%) > dichlorocarbanilide (55 +/- 20%) > fipronil (18 +/- 22%). Median concentrations of organohalogens were typically higher in anaerobically than in aerobically digested sludges, and peaked at 27 600 +/- 9600 and 15 800 +/- 8200 microg kg(-1) for triclocarban and triclosan, respectively. Mass balances obtained for three primary pesticides in six activated sludge treatment plants employing anaerobic digestion suggested a decreasing overall persistence from fipronil (97 +/- 70%) to triclocarban (87 +/- 29%) to triclosan (28 +/- 30%). Nationwide release of the investigated organohalogens to agricultural land via municipal sludge recycling and into surface waters is estimated to total 258 000 +/- 110 00 kg year(-1) (mean +/- 95% confidence interval), with most of this mass derived from antimicrobial consumer products of daily use. This study addresses some of the data gaps identified by the National Research Council in its 2002 study on standards and practices of biosolids application on land.

Effect of pH and ionic strength on exposure and toxicity of encapsulated lambda-cyhalothrin to Daphnia magna.

PubMed

Son, Jino; Hooven, Louisa A; Harper, Bryan; Harper, Stacey L

2015-12-15

Encapsulation of pesticide active ingredients in polymers has been widely employed to control the release of poorly water-soluble active ingredients. Given the high dispersibility of these encapsulated pesticides in water, they are expected to behave differently compared to their active ingredients; however, our current understanding of the fate and effects of encapsulated pesticides is still limited. In this study, we employed a central composite design (CCD) to investigate how pH and ionic strength (IS) affect the hydrodynamic diameter (HDD) and zeta potential of encapsulated λ-cyhalothrin and how those changes affect the exposure and toxicity to Daphnia magna. R(2) values greater than 0.82 and 0.84 for HDD and zeta potential, respectively, irrespective of incubation time suggest those changes could be predicted as a function of pH and IS. For HDD, the linear factor of pH and quadratic factor of pH×pH were found to be the most significant factors affecting the change of HDD at the beginning of incubation, whereas the effects of IS and IS×IS became significant as incubation time increased. For zeta potential, the linear factor of IS and quadratic factor of IS×IS were found to be the most dominant factors affecting the change of zeta potential of encapsulated λ-cyhalothrin, irrespective of incubation time. The toxicity tests with D. magna under exposure conditions in which HDD or zeta potential of encapsulated λ-cyhalothrin was maximized or minimized in the overlying water also clearly showed the worst-case exposure condition to D. magna was when the encapsulated λ-cyhalothrin is either stable or small in the overlying water. Our results show that water quality could modify the fate and toxicity of encapsulated λ-cyhalothrin in aquatic environments, suggesting understanding their aquatic interactions are critical in environmental risk assessment. Herein, we discuss the implications of our findings for risk assessment. Copyright © 2015 Elsevier B.V. All rights reserved.

Atrazine and metolachlor occurrence in shallow ground water of the United States, 1993 to 1995: Relations to explanatory factors

USGS Publications Warehouse

Kolpin, D.W.; Barbash, J.E.; Gilliom, R.J.

2002-01-01

Since 1991, the U.S. Geological Survey has been conducting the National Water Quality Assessment (NAWQA) Program to determine the quality of the Nation's water resources. In an effort to obtain a better understanding of why pesticides are found in shallow ground water on a national scale, a set of factors likely to affect the fate and transport of two herbicides in the subsurface were examined. Atrazine and metolachlor were selected for this discussion because they were among the most frequently detected pesticides in ground water during the first phase of the NAWQA Program (1993 to 1995), and each was the most frequently detected compound in its chemical class (triazines and acetanilides, respectively). The factors that most strongly correlated with the frequencies of atrazine detection in shallow ground-water networks were those that provided either: (1) an indication of the potential susceptibility of ground water to atrazine contamination, or (2) an indication of relative ground-water age. The factors most closely related to the frequencies of metolachlor detection in ground water, however, were those that estimated or indicated the intensity of the agricultural use of metolachlor. This difference is probably the result of detailed use estimates for these compounds being available only for agricultural settings. While atrazine use is relatively extensive in nonagricultural settings, in addition to its widespread agricultural use, metolachlor is used almost exclusively for agricultural purposes. As a result, estimates of agricultural applications provide a less reliable indication of total chemical use for atrazine than for metolachlor. A multivariate analysis demonstrated that the factors of interest explained about 50 percent of the variance in atrazine and metolachlor detection frequencies among the NAWQA land-use studies examined. The inclusion of other factors related to pesticide fate and transport in ground water, or improvements in the quality and accuracy of the data employed for the factors examined, may help explain more of the remaining variance in the frequencies of atrazine and metolachlor detection.

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

PubMed Central

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

2016-01-01

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

Characterization of adsorption and degradation of diuron in carbonatic and noncarbonatic soils.

PubMed

Kasozi, Gabriel N; Nkedi-Kizza, Peter; Agyin-Birikorang, Sampson; Zimmerman, Andrew R

2010-01-27

The adsorption and degradation of the pesticide diuron in carbonatic and noncarbonatic soils were investigated to better understand the fate and transport of diuron in the environment. Batch adsorption experiments yielded isotherms that were well-described by the linear model. Adsorption coefficients normalized to soil organic carbon content (K(oc)) were lowest for carbonatic soils, averaging 259 +/- 48 (95% CI), 558 +/- 109, 973 +/- 156, and 2090 +/- 1054 for carbonatic soils, Histosols, Oxisols, and Spodosols, respectively. In addition, marl-carbonatic soils had much lower K(oc) values (197 +/- 27) than nonmarl-carbonatic soils. Diuron degradation data fit a first-order reaction kinetics model, yielding half-lives in soils ranging from 40 to 267 days. There was no significant difference between the average diuron degradation rate coefficients of each of the soil groups studied. Given the low adsorption capacity of carbonatic soils, it may be advisable to lower herbicide application rates in agricultural regions with carbonatic soils such as southern Florida to protect aquatic ecosystems and water quality.

Role of solute-transport models in the analysis of groundwater salinity problems in agricultural areas

USGS Publications Warehouse

Konikow, Leonard F.

1981-01-01

Undesirable salinity increases occur in both groundwater and surface water and are commonly related to agricultural practices. Groundwater recharge from precipitation or irrigation will transport and disperse residual salts concentrated by evapotranspiration, salts leached from soil and aquifer materials, as well as some dissolved fertilizers and pesticides. Where stream salinity is affected by agricultural practices, the increases in salt load usually are attributable mostly to a groundwater component of flow. Thus, efforts to predict, manage, or control stream salinity increases should consider the role of groundwater in salt transport. Two examples of groundwater salinity problems in Colorado, U.S.A., illustrate that a model which simulates accurately the transport and dispersion of solutes in flowing groundwater can be (1) a valuable investigative tool to help understand the processes and parameters controlling the movement and fate of the salt, and (2) a valuable management tool for predicting responses and optimizing the development and use of the total water resource. ?? 1981.

Anaerobic biotransformation of organoarsenical pesticides monomethylarsonic acid and dimethylarsinic acid

USGS Publications Warehouse

Sierra-Alvarez, R.; Yenal, U.; Feld, J.A.; Kopplin, M.; Gandolfi, A.J.; Garbarino, J.R.

2006-01-01

Monomethylarsonic acid (MMAV) and dimethylarsinic acid (DMAV) are extensively utilized as pesticides, introducing large quantities of arsenic into the environment. Once released into the environment, these organoarsenicals are subject to microbial reactions. Aerobic biodegradation of MMAV and DMAV has been evaluated, but little is known about their fate in anaerobic environments. The objective of this study was to evaluate the biotransformation of MMAV and DMAV in anaerobic sludge. Biologically mediated conversion occurred under methanogenic or sulfate-reducing conditions but not in the presence of nitrate. Monomethylarsonous acid (MMAIII) was consistently observed as an important metabolite of MMAV degradation, and it was recovered in molar yields ranging from 5 to 47%. The main biotransformation product identified from DMAV metabolism was MMAV, which was recovered in molar yields ranging from 8 to 65%. The metabolites indicate that reduction and demethylation are important steps in the anaerobic bioconversion of MMAV and DMAV, respectively. ?? 2006 American Chemical Society.

Nutrients, suspended sediment, and pesticides in waters of the Red River of the North Basin, Minnesota, North Dakota, and South Dakota, 1970-90

USGS Publications Warehouse

Tornes, L.H.; Brigham, M.E.

1994-01-01

A relatively large fraction of stream samples had detectable quantities of 2,4-D, a- and y-HCH, and atrazine. These samples covered time spans of as much as 15 years and were from sites downstream from large drainage basins; however, concentrations were well below US EPA MCLs. One county-level study showed higher 2,4-D concentrations at upstream sites than at the outlet from a small basin. This indicates that downstream sites may fail to show impaired water-quality and the fate of pesticides used in the basin. Following the 1972 ban on DDT, concentrations of DDT in fish samples from the Red River of the North quickly decreased. Fish concentrations of DDE and DDD decreased more slowly. Low levels of DDE and DDD were detected in fish 14 years after the DDT ban.

Watershed Regressions for Pesticides (WARP) models for predicting stream concentrations of multiple pesticides

USGS Publications Warehouse

Stone, Wesley W.; Crawford, Charles G.; Gilliom, Robert J.

2013-01-01

Watershed Regressions for Pesticides for multiple pesticides (WARP-MP) are statistical models developed to predict concentration statistics for a wide range of pesticides in unmonitored streams. The WARP-MP models use the national atrazine WARP models in conjunction with an adjustment factor for each additional pesticide. The WARP-MP models perform best for pesticides with application timing and methods similar to those used with atrazine. For other pesticides, WARP-MP models tend to overpredict concentration statistics for the model development sites. For WARP and WARP-MP, the less-than-ideal sampling frequency for the model development sites leads to underestimation of the shorter-duration concentration; hence, the WARP models tend to underpredict 4- and 21-d maximum moving-average concentrations, with median errors ranging from 9 to 38% As a result of this sampling bias, pesticides that performed well with the model development sites are expected to have predictions that are biased low for these shorter-duration concentration statistics. The overprediction by WARP-MP apparent for some of the pesticides is variably offset by underestimation of the model development concentration statistics. Of the 112 pesticides used in the WARP-MP application to stream segments nationwide, 25 were predicted to have concentration statistics with a 50% or greater probability of exceeding one or more aquatic life benchmarks in one or more stream segments. Geographically, many of the modeled streams in the Corn Belt Region were predicted to have one or more pesticides that exceeded an aquatic life benchmark during 2009, indicating the potential vulnerability of streams in this region.

The geochemistry of pesticides

USGS Publications Warehouse

Barbash, Jack E.

2007-01-01

The mid-1970s marked a major turning point in human history, for it was at that moment that the ability of the Earth’s ecosystems to absorb most of the biological impacts of human activities appears to have been exceeded by the magnitude of those impacts. This conclusion is based partly upon estimates of the rate of carbon dioxide emission during the combustion of fossil fuels, relative to the rate of its uptake by terrestrial ecosystems (Loh, 2002). A very different threshold, however, had already been crossed several decades earlier with the birth of the modern chemical industry, which produced novel substances for which no such natural assimilative capacity existed. Among these new chemical compounds, none has posed a greater challenge to the planet’s ecosystems than synthetic pesticides, compounds that have been intentionally released into the hydrologic system in vast quantities—several hundred million pounds of active ingredient (a.i.) per year in the United States alone (Donaldson et al., 2002)—for many decades. To gauge the extent to which we are currently able to assess the environmental implications of this new development in the Earth’s history, this chapter presents an overview of current understanding regarding the sources, transport, fate, and biological effects of pesticides, their transformation products, and selected adjuvants in the hydrologic system. (Adjuvants are the so-called inert ingredients included in commercial pesticide formulations to enhance the effectiveness of the active ingredients.)

Inoculation of soil with an Isoproturon degrading microbial community reduced the pool of "real non-extractable" Isoproturon residues.

PubMed

Zhu, Xiaomin; Schroll, Reiner; Dörfler, Ulrike; Chen, Baoliang

2018-03-01

During pesticides degradation, biogenic non-extractable residues ("apparent NER") may not share the same environmental fate and risks with the "real NER" that are bound to soil matrix. It is not clear how microbial community (MC) inoculation for pesticides degradation would influence the NER composition. To investigate degradation efficiency of pesticides Isoproturon (IPU) and NER composition following MC inoculation, clay particles harboring MC that contains the IPU degrading strain, Sphingomonas sp., were inoculated into soil receiving 14 C-labeled IPU addition. Mineralization of IPU was greatly enhanced with MC inoculation that averagely 55.9% of the applied 14 C-IPU was consumed up into 14 CO 2 during 46 days soil incubation. Isoproturon degradation was more thorough with MC than that in the control: much less amount of metabolic products (4.6% of applied IPU) and NER (35.4%) formed in MC treatment, while the percentages were respectively 30.3% for metabolites and 49.8% for NER in the control. Composition of NER shifted with MC inoculation, that relatively larger amount of IPU was incorporated into the biogenic "apparent NER" in comparison with "real NER". Besides its well-recognized role on enhancing mineralization, MC inoculation with clay particles benefits soil pesticides remediation in term of reducing "real NER" formation, which has been previously underestimated. Copyright © 2017 Elsevier Inc. All rights reserved.

The geochemistry of pesticides

USGS Publications Warehouse

Barbash, J.E.

2003-01-01

The mid-1970s marked a major turning point in human history, for it was at that moment that the ability of the Earth's ecosystems to absorb most of the biological impacts of human activities appears to have been exceeded by the magnitude of those impacts. This conclusion is based partly upon estimates of the rate of carbon dioxide emission during the combustion of fossil fuels, relative to the rate of its uptake by terrestrial ecosystems (Loh, 2002). A very different threshold, however, had already been crossed several decades earlier with the birth of the modern chemical industry, which produced novel substances for which no such natural assimilative capacity existed. Among these new chemical compounds, none has posed a greater challenge to the planet's ecosystems than synthetic pesticides, compounds that have been intentionally released into the hydrologic system in vast quantities—several hundred million pounds of active ingredient (a.i.) per year in the United States alone (Donaldson et al., 2002)—for many decades. To gauge the extent to which we are currently able to assess the environmental implications of this new development in the Earth's history, this chapter presents an overview of current understanding regarding the sources, transport, fate, and biological effects of pesticides, their transformation products, and selected adjuvants in the hydrologic system. (Adjuvants are the so-called inert ingredients included in commercial pesticide formulations to enhance the effectiveness of the active ingredients.)

The Geochemistry of Pesticides

NASA Astrophysics Data System (ADS)

Barbash, J. E.

2003-12-01

The mid-1970s marked a major turning point in human history, for it was at that moment that the ability of the Earth's ecosystems to absorb most of the biological impacts of human activities appears to have been exceeded by the magnitude of those impacts. This conclusion is based partly upon estimates of the rate of carbon dioxide emission during the combustion of fossil fuels, relative to the rate of its uptake by terrestrial ecosystems (Loh, 2002). A very different threshold, however, had already been crossed several decades earlier with the birth of the modern chemical industry, which produced novel substances for which no such natural assimilative capacity existed. Among these new chemical compounds, none has posed a greater challenge to the planet's ecosystems than synthetic pesticides, compounds that have been intentionally released into the hydrologic system in vast quantities - several hundred million pounds of active ingredient per year in the United States alone ( Donaldson et al., 2002) - for many decades. To gauge the extent to which we are currently able to assess the environmental implications of this new development in the Earth's history, this chapter presents an overview of current understanding regarding the sources, transport, fate and biological effects of pesticides, their transformation products, and selected adjuvants in the hydrologic system. (Adjuvants are the so-called "inert ingredients" included in commercial pesticide formulations to enhance the effectiveness of the active ingredients.)

Study of processes influencing bioavailability of pesticides in wood-soil systems: Effect of different factors.

PubMed

Marín-Benito, J M; Herrero-Hernández, E; Rodríguez-Cruz, M S; Arienzo, M; Sánchez-Martín, M J

2017-05-01

Lignocellulosic wastes and by-products containing lignin are now available in large amounts from forestry and industrial activities, and could be promising organic materials for the biosorption of pesticides by soils in order to reduce point-source pollution. Adding these materials to soil requires understanding the process of pesticide sorption-desorption by wood-soils, as sorption capacity could increase, with changes in pesticide bioavailability and final fate. The objective of this work was to study the effect that pine and oak wood added to soils had on the sorption/desorption of the pesticides linuron, alachlor, and metalaxyl. Experiments were conducted with two sandy loam and sandy clay soils each amended with two wood doses (5% and 50%) after different incubation times (0, 5 and 12 months). A low wood dose (5%) had no significant impact on the sorption (K f ) of alachlor, but K f increased for linuron (up to 5.4-1.7 times) and metalaxyl (up to 4.4 and 8.6 times) in all wood-soil systems. The results were not significantly different after different incubation times. The desorption results indicated that wood decreases the sorption irreversibility of alachlor, and increases that of linuron and metalaxyl, with a varying effect of the wood-soil incubation time. The addition of a high wood dose to soil (50%) was more significant for increasing the sorption of all the pesticides, and the sorbed amounts remaining after desorption (>49% for linuron, >33% for alachlor and >6% for metalaxyl), although there was no apparent discrimination between the two types of woods. The role of the nature of the organic carbón (K oc values) for sorption was evidenced for alachlor and metalaxyl, but not for linuron. These outcomes are of interest for extending wood application to soil as a barrier for avoiding environmental risk by point-source pollution due to the use and management of pesticides in farming systems. Copyright © 2017 Elsevier Inc. All rights reserved.

Rapid quantification of pharmaceuticals and pesticides in passive samplers using ultra high performance liquid chromatography coupled to high resolution mass spectrometry.

PubMed

Wille, Klaas; Claessens, Michiel; Rappé, Karen; Monteyne, Els; Janssen, Colin R; De Brabander, Hubert F; Vanhaecke, Lynn

2011-12-23

The presence of both pharmaceuticals and pesticides in the aquatic environment has become a well-known environmental issue during the last decade. An increasing demand however still exists for sensitive and reliable monitoring tools for these rather polar contaminants in the marine environment. In recent years, the great potential of passive samplers or equilibrium based sampling techniques for evaluation of the fate of these contaminants has been shown in literature. Therefore, we developed a new analytical method for the quantification of a high number of pharmaceuticals and pesticides in passive sampling devices. The analytical procedure consisted of extraction using 1:1 methanol/acetonitrile followed by detection with ultra-high performance liquid chromatography coupled to high resolution and high mass accuracy Orbitrap mass spectrometry. Validation of the analytical method resulted in limits of quantification and recoveries ranging between 0.2 and 20 ng per sampler sheet and between 87.9 and 105.2%, respectively. Determination of the sampler-water partition coefficients of all compounds demonstrated that several pharmaceuticals and most pesticides exert a high affinity for the polydimethylsiloxane passive samplers. Finally, the developed analytical methods were used to measure the time-weighted average (TWA) concentrations of the targeted pollutants in passive samplers, deployed at eight stations in the Belgian coastal zone. Propranolol, carbamazepine and seven pesticides were found to be very abundant in the passive samplers. These obtained long-term and large-scale TWA concentrations will contribute in assessing the environmental and human health risk of these emerging pollutants. Copyright © 2011 Elsevier B.V. All rights reserved.

Distribution mode and environmental risk of POP pesticides such as endosulfan under the agricultural practice of straw incorporating.

PubMed

Wang, Jie; Li, Li; Liu, Jianguo; Ti, Bowen

2017-01-01

The practice of incorporating post-harvest crop waste is widely used because it maintains soil fertility and avoids environmental pollution from straw burning. However, the practice of straw incorporation may also retain the pesticides that are applied to crop plants, which may pose a potential long term risk to local and regional environments if the applied pesticide is a Persistent, Bioaccumulative, and Toxic (PBT) substance or a Persistent Organic Pollutant (POP). Here we investigate the influence of the "receiving-retention-release" route on the distribution of a POP pesticide (endosulfan) and the associated environmental risk among different environmental compartments. Our study indicates that most endosulfan enters the atmosphere (φ atmosphere  = 64.5-72.5%), which is dominated by the indirect route of volatilization from crop plants (φ atmosphere, indirect  = 54.7-70.3%). In contrast, soil releases are minor (φ soil  = 10.8-20.5%), and are dominated by direct release during application (φ soil, direct  = 8.0-18.0%). Under the practice of straw incorporation, the use of endosulfan posed an environmental risk to agricultural soil. In addition, the atmospheric deposition of endosulfan also posed an environmental risk to sediment. The study highlights the significance of the "receiving-retention-release" route by crop plants in determining the fate of POP pesticides associated with straw incorporation; hence complementing the current methodology for assessing the environmental risk of these compounds. Copyright © 2016 Elsevier Ltd. All rights reserved.

Selected current-use and historic-use pesticides in air and seawater of the Bohai and Yellow Seas, China

NASA Astrophysics Data System (ADS)

Zhong, Guangcai; Tang, Jianhui; Xie, Zhiyong; Möller, Axel; Zhao, Zhen; Sturm, Renate; Chen, Yingjun; Tian, Chongguo; Pan, Xiaohui; Qin, Wei; Zhang, Gan; Ebinghaus, Ralf

2014-01-01

Consumption of pesticides in China has increased rapidly in recent years; however, occurrence and fate of current-use pesticides (CUPs) in China coastal waters are poorly understood. Globally banned pesticides, so-called historic-use pesticides (HUPs), are still commonly observed in the environment. In this work, air and surface seawater samples taken from the Bohai and Yellow Seas in May 2012 were analyzed for CUPs including trifluralin, quintozene, chlorothalonil, dicofol, chlorpyrifos, and dacthal, as well as HUPs (hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), and endosulfan). CUP profile in both air and seawater samples generally reflected their consumption patterns in China. HUPs in the air and seawater samples were in comparable levels as those of CUPs with high concentrations. α-Endosulfan, dicofol, and chlorothalonil showed strong net deposition likely resulting from their intensive use in recent years, while CUPs with low consumption amount (quintozene and dacthal) were close to equilibrium at most samplings sites. Another CUP with high usage amout (i.e., chlorpyrifos) underwent volatilization possibly due to its longer half-life in seawater than that in air. α-HCH and γ-HCH were close to equilibrium in the Bohai Sea, but mainly underwent net deposition in the Yellow Sea. The net deposition of α-HCH could be attributed to polluted air pulses from the East China identified by air mass back trajectories. β-HCH showed net volatilization in the Bohai Sea, which was driven by its relative enrichment in seawater. HCB either slightly favored net volatilization or was close to equilibrium in the Bohai and Yellow Seas.

Characterization of the environmental fate of Bacillus thuringiensis var. kaurstaki (Btk) after pest eradication efforts in Seattle, WA and Fairfax county, VA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ticknor, Lawrence; Van Cuyk, Sheila M; Deshpande, Alina

Understanding the fate of biological agents in the environment will be critical to recovery and restoration efforts after a biological attack. Los Alamos National Laboratory (LANL) is conducting experiments in the Seattle, WA and Fairfax County, VA areas to study agent fate in urban environments. As part of their gypsy moth suppression efforts, Washington State and Fairfax County have sprayed Bacillus thuringiensis var. kurstaki (Btk), a common organic pesticide for decades. Many of the spray zones have been in or near urban areas. LANL has collected surface and bulk samples from historical Seattle spray zones to characterize how long Btkmore » persists at detectable levels in the environment, and how long it remains viable in different environmental matrices. This work will attempt to address three questions. First, how long does the agent remain viable at detectable levels? Second, what is the approximate magnitude and duration of resuspension? And third, does the agent transport into buildings? Data designed to address the first question will be presented. Preliminary results indicate Btk remains viable in the environment for at least two years.« less

Determination of metalaxyl and identification of adjuvants in wettable powder pesticide technical formulas.

PubMed

Pose-Juan, Eva; Rial-Otero, Raquel; Martínez-Carballo, Elena; López-Periago, Eugenio; Simal-Gándara, Jesús

2009-07-01

Foliar runoff is one of the most important processes affecting off-target movement of fungicides. In this way, Ridomil Gold Plus and Ridomil Gold MZ are two types of wettable powder technical formulations which contain metalaxyl and they are used for such a purpose. A method for quantitative determination of metalaxyl in pesticide formulas has been developed, validated, and subsequently applied to Ridomil Gold Plus and Ridomil Gold MZ. The method employs liquid-liquid extraction followed by liquid chromatography coupled with UV detection (LC-UV), using gas chromatography coupled with mass spectrometry as confirmation technique and to carry out a screening of organic adjuvants of these two selected pesticide formulas. Metalaxyl of 26.5 and 41 g/kg was detected in Ridomil Gold Plus and Ridomil Gold MZ, close to the manufacture specified level of 25 and 40 g/kg, respectively. Activator and utility adjuvants were detected in these two wettable powder technical formulations. Only methyl-ester-based surfactants were found within the group of nonionic surfactants, but the long-term fates of most adjuvants in soils and elsewhere in the environment are largely unknown, partially because of the lack of long-term monitoring data.

Insecticide dissipation from soil and plant surfaces in tropical horticulture of southern Benin, West Africa.

PubMed

Rosendahl, Ingrid; Laabs, Volker; Atcha-Ahowé, Cyrien; James, Braima; Amelung, Wulf

2009-06-01

In Sub-Saharan Africa, horticulture provides livelihood opportunities for millions of people, especially in urban and peri-urban areas. Although the vegetable agroecosystems are often characterized by intensive pesticide use, risks resulting therefrom are largely unknown under tropical horticultural conditions. The objective of this study therefore was to study the fate of pesticides in two representative horticultural soils (Acrisol and Arenosol) and plants (Solanum macrocarpon L.) after field application and thus to gain first insight on environmental persistence and dispersion of typical insecticides used in vegetable horticulture in Benin, West Africa. On plant surfaces, dissipation was rapid with half lives ranging from 2 to 87 h (alpha-endosulfan < beta-endosulfan < deltamethrin). Soil dissipation was considerably slower than dissipation from plant surfaces with half-lives ranging from 3 (diazinon) to 74 d (total endosulfan), but persistence of pesticides in soil was still reduced compared to temperate climates. Nevertheless, for deltamethrin and endosulfan, a tendency for mid-term accumulation in soil upon repeated applications was observed. The soil and plant surface concentrations of the metabolite endosulfan sulfate increased during the entire trial period, indicating that this compound is a potential long-term pollutant even in tropical environments.

Characterization of spectral responses of dissolved organic matter (DOM) for atrazine binding during the sorption process onto black soil.

PubMed

Wang, Yifan; Zhang, Xinyuan; Zhang, Xing; Meng, Qingjuan; Gao, Fengjie; Zhang, Ying

2017-08-01

This study was aim to investigate the interaction between soil-derived dissolved organic matter (DOM) and atrazine as a kind of pesticides during the sorption process onto black soil. According to the experimental data, the adsorption capacity of Soil + DOM, Soil and DOM were 41.80, 31.45 and 9.35 mg kg -1 , separately, which indicated that DOM significantly enhanced the adsorption efficiency of atrazine by soil. Data implied that the pseudo-second-order kinetic equation could well explain the adsorption process. The adsorption isotherms (R 2  > 0.99) had a satisfactory fit in both Langmuir and Freundlich models. Three-dimensional excitation-emission matrix (3D-EEM), synchronous fluorescence, two-dimensional correlation spectroscopy (2D-COS) and Fourier transform infrared spectroscopy (FT-IR) were selected to analyze the interaction between DOM and atrazine. 3D-EEM showed that humic acid-like substances were the main component of DOM. The fluorescence of DOM samples were gradually quenched with the increased of atrazine concentrations. Synchronous fluorescence spectra showed that static fluorescence quenching was the main quenching process. 2D-COS indicated that the order of the spectral changes were as following: 336 nm > 282 nm. Furthermore, the fluorescence quenching of humic-like fraction occurred earlier than that of protein-like fraction under atrazine surroundings. FT-IR spectra indicated that main compositions of soil DOM include proteins, polysaccharides and humic substances. The findings of this study are significant to reveal DOM played an important role in the environmental fate of pesticides during sorption process onto black soil and also provide more useful information for understanding the interaction between DOM and pesticides by using spectral responses. Copyright © 2017. Published by Elsevier Ltd.

Occurrence, fate and effects of azoxystrobin in aquatic ecosystems: a review.

PubMed

Rodrigues, Elsa Teresa; Lopes, Isabel; Pardal, Miguel Ângelo

2013-03-01

The use of pesticides for crop protection may result in the presence of toxic residues in environmental matrices. In the aquatic environment, pesticides might freely dissolve in the water or bind to suspended matter and to the sediments, and might be transferred to the organisms' tissues during bioaccumulation processes, resulting in adverse consequences to non-target species. One such group of synthetic organic pesticides widely used worldwide to combat pathogenic fungi affecting plants is the strobilurin chemical group. Whereas they are designed to control fungal pathogens, their general modes of action are not specific to fungi. Consequently, they can be potentially toxic to a wide range of non-target organisms. The present work had the intent to conduct an extensive literature review to find relevant research on the occurrence, fate and effects of azoxystrobin, the first patent of the strobilurin compounds, in aquatic ecosystems in order to identify strengths and gaps in the scientific database. Analytical procedures and existing legislation and regulations were also assessed. Data gathered in the present review revealed that analytical reference standards for the most relevant environmental metabolites of azoxystrobin are needed. Validated confirmatory methods for complex matrices, like sediment and aquatic organisms' tissues, are very limited. Important knowledge of base-line values of azoxystrobin and its metabolites in natural tropical and estuarine/marine ecosystems is lacking. Moreover, some environmental concentrations of azoxystrobin found in the present review are above the Regulatory Acceptable Concentration (RAC) in what concerns risk to aquatic invertebrates and the No Observed Ecologically Adverse Effect Concentration (NOEAEC) reported for freshwater communities. The present review also showed that there are very few data on azoxystrobin toxicity to different aquatic organisms, especially in what concerns estuarine/marine organisms. Besides, toxicity studies mostly address azoxystrobin and usually neglect the more relevant environmental metabolites. Further work is also required in what concerns effects of exposure to multi-stressors, e.g. pesticide mixtures. Even though Log K(ow) for azoxystrobin and R234886, the main metabolite of azoxystrobin in water, are below 3, the bio-concentration factor and the bioaccumulation potential for azoxystrobin are absent in the literature. Moreover, no single study on bioaccumulation and biomagnification processes was found in the present review. Copyright © 2012 Elsevier Ltd. All rights reserved.

A review of model applications for structured soils: b) Pesticide transport.

PubMed

Köhne, John Maximilian; Köhne, Sigrid; Simůnek, Jirka

2009-02-16

The past decade has seen considerable progress in the development of models simulating pesticide transport in structured soils subject to preferential flow (PF). Most PF pesticide transport models are based on the two-region concept and usually assume one (vertical) dimensional flow and transport. Stochastic parameter sets are sometimes used to account for the effects of spatial variability at the field scale. In the past decade, PF pesticide models were also coupled with Geographical Information Systems (GIS) and groundwater flow models for application at the catchment and larger regional scales. A review of PF pesticide model applications reveals that the principal difficulty of their application is still the appropriate parameterization of PF and pesticide processes. Experimental solution strategies involve improving measurement techniques and experimental designs. Model strategies aim at enhancing process descriptions, studying parameter sensitivity, uncertainty, inverse parameter identification, model calibration, and effects of spatial variability, as well as generating model emulators and databases. Model comparison studies demonstrated that, after calibration, PF pesticide models clearly outperform chromatographic models for structured soils. Considering nonlinear and kinetic sorption reactions further enhanced the pesticide transport description. However, inverse techniques combined with typically available experimental data are often limited in their ability to simultaneously identify parameters for describing PF, sorption, degradation and other processes. On the other hand, the predictive capacity of uncalibrated PF pesticide models currently allows at best an approximate (order-of-magnitude) estimation of concentrations. Moreover, models should target the entire soil-plant-atmosphere system, including often neglected above-ground processes such as pesticide volatilization, interception, sorption to plant residues, root uptake, and losses by runoff. The conclusions compile progress, problems, and future research choices for modelling pesticide displacement in structured soils.

Simulation of stream discharge and transport of nitrate and selected herbicides in the Mississippi River Basin

NASA Astrophysics Data System (ADS)

Broshears, Robert E.; Clark, Gregory M.; Jobson, Harvey E.

2001-05-01

Stream discharge and the transport of nitrate, atrazine, and metolachlor in the Mississippi River Basin were simulated using the DAFLOW/BLTM hydrologic model. The simulated domain for stream discharge included river reaches downstream from the following stations in the National Stream Quality Accounting Network: Mississippi River at Clinton, IA; Missouri River at Hermann, MO; Ohio River at Grand Chain, IL; and Arkansas River at Little Rock, AR. Coefficients of hydraulic geometry were calibrated using data from water year 1996; the model was validated by favourable simulation of observed discharges in water years 1992-1994. The transport of nitrate, atrazine, and metolachlor was simulated downstream from the Mississippi River at Thebes, IL, and the Ohio River at Grand Chain. Simulated concentrations compared favourably with observed concentrations at Baton Rouge, LA. Development of this model is a preliminary step in gaining a more quantitative understanding of the sources and fate of nutrients and pesticides delivered from the Mississippi River Basin to the Gulf of Mexico. Published in 2001 by John Wiley & Sons, Ltd.

Mitigation of two pyrethroid insecticides in a Mississippi Delta constructed wetland.

PubMed

Moore, M T; Cooper, C M; Smith, S; Cullum, R F; Knight, S S; Locke, M A; Bennett, E R

2009-01-01

Constructed wetlands are a suggested best management practice to help mitigate agricultural runoff before entering receiving aquatic ecosystems. A constructed wetland system (180 m x 30 m), comprising a sediment retention basin and two treatment cells, was used to determine the fate and transport of simulated runoff containing the pyrethroid insecticides lambda-cyhalothrin and cyfluthrin, as well as suspended sediment. Wetland water, sediment, and plant samples were collected spatially and temporally over 55 d. Results showed 49 and 76% of the study's measured lambda-cyhalothrin and cyfluthrin masses were associated with vegetation, respectively. Based on conservative effects concentrations for invertebrates and regression analyses of maximum observed wetland aqueous concentrations, a wetland length of 215 m x 30 m width would be required to adequately mitigate 1% pesticide runoff from a 14 ha contributing area. Results of this experiment can be used to model future design specifications for constructed wetland mitigation of pyrethroid insecticides.

Agricultural sources of contaminants of emerging concern and adverse health effects on freshwater fish

USGS Publications Warehouse

Tillitt, Donald E.; Buxton, Herbert T.

2011-01-01

Agricultural contaminants of emerging concern (CECs) are generally thought of as certain classes of chemicals associated with animal feeding and production facilities. Veterinary pharmaceuticals used in animal food production systems represent one of the largest groups of CECs. In our review, we discuss the extensive increase in use of antibiotics in animal feeding operations (AFOs) around the world. AFOs are a major consumer of antibiotics and other veterinary pharmaceuticals and over the past decade there has been growing information on the occurrence, release, and fate of CECs from animal food production operations, including the application of pharmaceutical-containing manure to agricultural fields and releases from waste lagoons. Concentrations of CECs in surface and ground water in proximity to AFOs correspond to their presence in the AFO wastes. In many cases, the environmental concentrations of agriculturally-derived CECs are below toxicity thresholds. Hormones and hormone replacement compounds are a notable exception, where chemical concentrations near AFOs can exceed concentrations known to cause adverse effects on endocrine-related functions in fish. In addition, some agricultural pesticides, once thought to be safe to non-target organisms, have demonstrated endocrine-related effects that may pose threats to fish populations in agricultural regions. That is, we have pesticides with emerging concerns, thus, the concern is emerging and not necessarily the chemical. In this light, one must consider certain agricultural pesticides to be included in the list of CECs. Even though agricultural pesticides are routinely evaluated in regulatory testing schemes which have been used for decades, the potential hazards of some pesticides have only recently been emerging. Emerging concerns of pesticides in fish include interference with hormone signaling pathways; additive (or more than additive) effects from pesticide mixtures; and adverse population-level effects at concentrations below predicted toxicity thresholds. Consequently, there is a need to evaluate the environmental concerns related to pesticide exposures to fish populations based on current biological and toxicological techniques. This presentation reviews some of the agricultural chemicals that have emerged as contaminants of concern and potentially threaten fish populations in agricultural watersheds.

Modeling nanomaterial environmental fate in aquatic systems.

PubMed

Dale, Amy L; Casman, Elizabeth A; Lowry, Gregory V; Lead, Jamie R; Viparelli, Enrica; Baalousha, Mohammed

2015-03-03

Mathematical models improve our fundamental understanding of the environmental behavior, fate, and transport of engineered nanomaterials (NMs, chemical substances or materials roughly 1-100 nm in size) and facilitate risk assessment and management activities. Although today's large-scale environmental fate models for NMs are a considerable improvement over early efforts, a gap still remains between the experimental research performed to date on the environmental fate of NMs and its incorporation into models. This article provides an introduction to the current state of the science in modeling the fate and behavior of NMs in aquatic environments. We address the strengths and weaknesses of existing fate models, identify the challenges facing researchers in developing and validating these models, and offer a perspective on how these challenges can be addressed through the combined efforts of modelers and experimentalists.

Fate of sessile droplet chemical agents in environmental substrates in the presence of physiochemical processes

NASA Astrophysics Data System (ADS)

Navaz, H. K.; Dang, A. L.; Atkinson, T.; Zand, A.; Nowakowski, A.; Kamensky, K.

2014-05-01

A general-purpose multi-phase and multi-component computer model capable of solving the complex problems encountered in the agent substrate interaction is developed. The model solves the transient and time-accurate mass and momentum governing equations in a three dimensional space. The provisions for considering all the inter-phase activities (solidification, evaporation, condensation, etc.) are included in the model. The chemical reactions among all phases are allowed and the products of the existing chemical reactions in all three phases are possible. The impact of chemical reaction products on the transport properties in porous media such as porosity, capillary pressure, and permeability is considered. Numerous validations for simulants, agents, and pesticides with laboratory and open air data are presented. Results for chemical reactions in the presence of pre-existing water in porous materials such as moisture, or separated agent and water droplets on porous substrates are presented. The model will greatly enhance the capabilities in predicting the level of threat after any chemical such as Toxic Industrial Chemicals (TICs) and Toxic Industrial Materials (TIMs) release on environmental substrates. The model's generality makes it suitable for both defense and pharmaceutical applications.

Comparison of two parametric methods to estimate pesticide mass loads in California's Central Valley

USGS Publications Warehouse

Saleh, Dina K.; Lorenz, David L.; Domagalski, Joseph L.

2011-01-01

Mass loadings were calculated for four pesticides in two watersheds with different land uses in the Central Valley, California, by using two parametric models: (1) the Seasonal Wave model (SeaWave), in which a pulse signal is used to describe the annual cycle of pesticide occurrence in a stream, and (2) the Sine Wave model, in which first-order Fourier series sine and cosine terms are used to simulate seasonal mass loading patterns. The models were applied to data collected during water years 1997 through 2005. The pesticides modeled were carbaryl, diazinon, metolachlor, and molinate. Results from the two models show that the ability to capture seasonal variations in pesticide concentrations was affected by pesticide use patterns and the methods by which pesticides are transported to streams. Estimated seasonal loads compared well with results from previous studies for both models. Loads estimated by the two models did not differ significantly from each other, with the exceptions of carbaryl and molinate during the precipitation season, where loads were affected by application patterns and rainfall. However, in watersheds with variable and intermittent pesticide applications, the SeaWave model is more suitable for use on the basis of its robust capability of describing seasonal variation of pesticide concentrations.

Modelling atmospheric transport of α-hexachlorocyclohexane in the Northern Hemispherewith a 3-D dynamical model: DEHM-POP

NASA Astrophysics Data System (ADS)

Hansen, K. M.; Christensen, J. H.; Brandt, J.; Frohn, L. M.; Geels, C.

2004-07-01

The Danish Eulerian Hemispheric Model (DEHM) is a 3-D dynamical atmospheric transport model originally developed to describe the atmospheric transport of sulphur into the Arctic. A new version of the model, DEHM-POP, developed to study the atmospheric transport and environmental fate of persistent organic pollutants (POPs) is presented. During environmental cycling, POPs can be deposited and re-emitted several times before reaching a final destination. A description of the exchange processes between the land/ocean surfaces and the atmosphere is included in the model to account for this multi-hop transport. The α-isomer of the pesticide hexachlorocyclohexane (α-HCH) is used as tracer in the model development. The structure of the model and processes included are described in detail. The results from a model simulation showing the atmospheric transport for the years 1991 to 1998 are presented and evaluated against measurements. The annual averaged atmospheric concentration of α-HCH for the 1990s is well described by the model; however, the shorter-term average concentration for most of the stations is not well captured. This indicates that the present simple surface description needs to be refined to get a better description of the air-surface exchange processes of POPs.

Modelling atmospheric transport of persistent organic pollutants in the Northern Hemisphere with a 3-D dynamical model: DEHM-POP

NASA Astrophysics Data System (ADS)

Hansen, K. M.; Christensen, J. H.; Brandt, J.; Frohn, L. M.; Geels, C.

2004-03-01

The Danish Eulerian Hemispheric Model (DEHM) is a 3-D dynamical atmospheric transport model originally developed to describe the atmospheric transport of sulphur into the Arctic. A new version of the model, DEHM-POP, developed to study the atmospheric transport and environmental fate of persistent organic pollutants (POPs) is presented. During environmental cycling, POPs can be deposited and re-emitted several times before reaching a final destination. A description of the exchange processes between the land/ocean surfaces and the atmosphere is included in the model to account for this multi-hop transport. The α-isomer of the pesticide hexachlorocyclohexane (α-HCH) is used as tracer in the model development. The structure of the model and processes included are described in detail. The results from a model simulation showing the atmospheric transport for the years 1991 to 1998 are presented and evaluated against measurements. The annual averaged atmospheric concentration of α-HCH for the 1990s is well described by the model; however, the shorter-term average concentration for most of the stations is not well captured. This indicates that the present simple surface description needs to be refined to get a better description of the air-surface exchange proceses of POPs.

Bacteria contribute to pesticide degradation in cryoconite holes in an Alpine glacier.

PubMed

Ferrario, Claudia; Pittino, Francesca; Tagliaferri, Ilario; Gandolfi, Isabella; Bestetti, Giuseppina; Azzoni, Roberto Sergio; Diolaiuti, Guglielmina; Franzetti, Andrea; Ambrosini, Roberto; Villa, Sara

2017-11-01

Organic contaminants deposited on glacier snow and ice are subject to partitioning and degradation processes that determine their environmental fate and, consequently, their accumulation in ice bodies. Among these processes, organic compound degradation by supraglacial bacteria has been investigated to a lesser extent than photo- and chemical degradation. We investigated biodegradation of the organophosphorus insecticide chlorpyrifos (CPF), a xenobiotic tracer that accumulates on glaciers after atmospheric medium- and long-range transport, by installing in situ microcosms on an Alpine glacier to simulate cryoconite hole systems. We found that biodegradation contributed to the removal of CPF from the glacier surface more than photo- and chemical degradation. The high concentration of CPF (2-3 μg g -1 w.w.) detected in cryoconite holes and the estimated half-life of this compound (35-69 days in glacier environment) indicated that biodegradation can significantly reduce CPF concentrations on glaciers and its runoff to downstream ecosystems. The metabolic versatility of cryoconite bacteria suggests that these habitats might contribute to the degradation of a wide class of pollutants. We therefore propose that cryoconite acts as a "biofilter" by accumulating both pollutants and biodegradative microbial communities. The contribution of cryoconite to the removal of organic pollutants should be included in models predicting the environmental fate of these compounds in cold areas. Copyright © 2017 Elsevier Ltd. All rights reserved.

Modeling of isotope fractionation at the catchment scale: How promising is compound specific isotope analysis (CSIA) as a tool for analyzing diffuse pollution by agrochemicals?

NASA Astrophysics Data System (ADS)

Lutz, S. R.; van Meerveld, H. J.; Waterloo, M. J.; Broers, H. P.; van Breukelen, B. M.

2012-04-01

Concentration measurements are indispensable for the assessment of subsurface and surface water pollution by agrochemicals such as pesticides. However, monitoring data is often ambiguous and easily misinterpreted as a decrease in concentration could be caused by transformation, dilution or changes in the application of the pesticide. In this context, compound specific isotope analysis (CSIA) has recently emerged as a complementary monitoring technique. It is based on the measurement of the isotopic composition (e.g. δ13C and δ2H) of the contaminant. Since transformation processes are likely accompanied by isotope fractionation, thus a change in this composition, CSIA offers the opportunity to gain additional knowledge about transport and degradation processes as well as to track pollutants back to their sources. Isotopic techniques have not yet been applied in a comprehensive way in the analysis of catchment-wide organic pollution. We therefore incorporated fractionation processes associated with the fate of pesticides into the numerical flow and solute transport model HydroGeoSphere in order to assess the feasibility of CSIA within the context of catchment monitoring. The model was set up for a hypothetical hillslope transect which drains into a river. Reactive solute transport was driven by two pesticides applications within one year and actual data for rainfall and potential evapotranspiration from a meteorological station in the Netherlands. Degradation of the pesticide was assumed to take place at a higher rate under the prevailing oxic conditions in the topsoil than in deeper, anoxic subsurface layers. In terms of CSIA, these two degradation pathways were associated with different strengths of isotope fractionation for both hydrogen and carbon atoms. By simulating changes in δ13C and δ2H, the share of the oxic and the anoxic reaction on the overall degradation could be assessed. Model results suggest that CSIA is suitable for assessing degradation of diffuse agrochemical pollutants in a relatively simple hydrological system. The simulated shifts in isotopic signals are within a range that could be detected with current isotope analytics. Concentrations in the stream vary significantly only for a short period during and after intense rainfall events. In contrast, CSIA values reveal longer response times such that isotopic shifts are likely to be detected in samples with a coarser temporal resolution. Rainfall events which result in fast lateral subsurface transport from the pollution source to the stream can be separated from those that lead to pollution migration through deeper subsurface zones with much longer travel times. Two-dimensional CSIA highlights an increasing importance of the oxic reaction in the topsoil during the wetter period of the year. In order to examine to which extent CSIA is applicable for more complex hydrological systems, it is projected to simulate isotope fractionation in a 3-dimensional catchment featuring additional processes such as migration from several pollution sources or in-stream degradation.

Coupling passive air sampling with emission estimates and chemical fate modeling for persistent organic pollutants (POPs): a feasibility study for Northern Europe.

PubMed

Gioia, Rosalinda; Sweetman, Andy J; Jones, Kevin C

2007-04-01

Passive air samplers (polyurethane foam disks) were deployed at 23 background locations along a broadly west-east transect in 8 northern European countries and analyzed for PCBs, PBDEs, PAHs, and a range of organochlorine pesticides (HCB, DDTs, and DDEs). PCBs and PAHs were highest at the center of the transect (Denmark) and lowest in northern Norway. HCB was relatively uniformly distributed, reflecting its persistence and high degree of mixing in air. Higher DDE and DDT levels occurred in Eastern Europe and at several sites in Central Europe. PBDE levels were generally similar at all sites, but lower for some locations in Eastern Europe and Ireland. Emissions information for PCBs, HCB, and PBDEs was used as input for a multi-media chemical fate model, to generate predicted air concentrations and compare with these measured values. Different scenarios were highlighted by this exercise: (i) country and compound combinations where the national inventory gave predicted air concentrations in close agreement with those measured (e.g., PCBs in the UK); (ii) country and compound combinations where predicted concentrations were well below those measured, but where advection of emissions from elsewhere is likely to be important (e.g., PCBs in Norway); (iii) consistent underestimation of compound concentrations by the emissions modeling (i.e., HCB); and (iv) general overestimation of ambient concentrations (i.e., PBDEs). Air mass trajectory analysis showed the likely role of long-range atmospheric transport (LRAT) on national levels. In general, advection from the south and west of Europe appeared to contribute to ambient POPs levels for countries in the center and northeast of the transect. Guidelines are presented as to how countries that want to assess their POPs source inventories can do so with this relatively cheap initial screening approach.

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

PubMed

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

2017-09-01

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

Tier 1 Rice Model for Estimating Pesticide Concentrations in Rice Paddies

EPA Science Inventory

The Tier 1 Rice Model estimates screening level aquatic concentrations of pesticides in rice paddies. It is a simple pesticide soil:water partitioning model with default values for water volume, soil mass, and organic carbon. Pesticide degradation is not considered in the mode...

Exploring tropical forest vegetation dynamics using the FATES model

NASA Astrophysics Data System (ADS)

Koven, C. D.; Fisher, R.; Knox, R. G.; Chambers, J.; Kueppers, L. M.; Christoffersen, B. O.; Davies, S. J.; Dietze, M.; Holm, J.; Massoud, E. C.; Muller-Landau, H. C.; Powell, T.; Serbin, S.; Shuman, J. K.; Walker, A. P.; Wright, S. J.; Xu, C.

2017-12-01

Tropical forest vegetation dynamics represent a critical climate feedback in the Earth system, which is poorly represented in current global modeling approaches. We discuss recent progress on exploring these dynamics using the Functionally Assembled Terrestrial Ecosystem Simulator (FATES), a demographic vegetation model for the CESM and ACME ESMs. We will discuss benchmarks of FATES predictions for forest structure against inventory sites, sensitivity of FATES predictions of size and age structure to model parameter uncertainty, and experiments using the FATES model to explore PFT competitive dynamics and the dynamics of size and age distributions in responses to changing climate and CO2.

Assessing the atmospheric oxidation of pesticides used to control mosquito populations in Houston, TX.

NASA Astrophysics Data System (ADS)

Usenko, S.; Clark, A. E.; Yoon, S.; Sheesley, R. J.

2016-12-01

In September 2013, NASA initiated the DISCOVER-AQ (Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality) Houston campaign, which collected satellite and ground-based data to better understand air quality in the Houston metropolitan area. In conjunction with DISCOVER-AQ, particulate matter samples including total suspended particle (TSP) and particulate matter less than 2.5 microns in aerodynamic diameter (PM2.5) were collected at four ground-based sites across Houston. Aliquots of PM samples were analyzed for pesticide used to control mosquito populations in urban areas. Pesticides extracted using pressurized liquid extraction and extracts were analyzed using gas chromatography mass spectrometry. These pesticides, also known as adulticides, are aerosolized and sprayed in neighborhoods throughout Houston around sunset in an effort to reduce or prevent the spread of diseases like West Nile Virus and Zika. When these pesticides enter the atmosphere they oxidize after reaction with ozone and nitrate radical and become more toxic and less volatile. The rate and specific mechanism associated with this urban chemistry is currently unknown, but has direct implications on public health from both a toxicological and disease control standpoint. Preliminary atmospheric measurements in Houston demonstrated significant nighttime oxidation of malathion to malaoxon. Atmospheric half-lives measured near downtown Houston where 10x lower than previous agriculture based studies ( 5 days to less than 24 hours). Atmospheric nighttime PM concentrations of adulticides exceeded 60 ng/m3, which is orders of magnitude greater than concentrations of organic tracers associated with incomplete combustion. This unique system also offers an opportunity to address some key scientific questions including focusing on SVOC urban fate and urban transport as well as nighttime oxidation.

Aquatic risk assessment of pesticides in Latin America.

PubMed

Carriquiriborde, Pedro; Mirabella, Paula; Waichman, Andrea; Solomon, Keith; Van den Brink, Paul J; Maund, Steve

2014-10-01

Latin America is anticipated to be a major growth market for agriculture and production is increasing with use of technologies such as pesticides. Reports of contamination of aquatic ecosystems by pesticides in Latin America have raised concerns about potential for adverse ecological effects. In the registration process of pesticides, all countries require significant data packages on aquatic toxicology and environmental fate. However, there are usually no specific requirements to conduct an aquatic risk assessment. To address this issue, the Society of Environmental Toxicology and Chemistry organized a workshop that brought together scientists from academia, government, and industry to review and elaborate on aquatic risk assessment frameworks that can be implemented into regulation of pesticides in Latin America. The workshop concluded that the international framework for risk assessments (protection goals, effects, and exposure assessments, risk characterization, and risk mitigation) is broadly applicable in Latin America but needs further refinement for the use in the region. Some of the challenges associated with these refinements are discussed in the article. It was recognized that there is potential for data sharing both within and outside of the region where conditions are similar. However, there is a need for research to compare local species and environmental conditions to those in other jurisdictions to be able to evaluate the applicability of data used in other countries. Development should also focus on human resources as there is a need to build local capacity and capability, and scientific collaboration and exchange between stakeholders in industry, government, and academia is also important. The meeting also emphasized that, although establishing a regionally relevant risk assessment framework is important, this also needs to be accompanied by enforcement of developed regulations and good management practices to help protect aquatic habitats. Education, training, and communication efforts are needed to achieve this. © 2014 SETAC.

Models for Pesticide Risk Assessment

EPA Pesticide Factsheets

EPA considers the toxicity of the pesticide as well as the amount of pesticide to which a person or the environments may be exposed in risk assessment. Scientists use mathematical models to predict pesticide concentrations in exposure assessment.

Modeling of temporal patterns and sources of atmospherically transported and deposited pesticides in ecosystems of concern: A case study of toxaphene in the Great Lakes

NASA Astrophysics Data System (ADS)

Li, Rong; Jin, Jiming

2013-10-01

have adverse effects on human health and the environment and can be transported through the atmosphere from application sites and deposited to sensitive ecosystems. This study applies a comprehensive multimedia regional pesticide fate and chemical transport modeling system that we developed to investigate the atmospheric transport and deposition of toxaphene to the Great Lakes. Simulated results predict a significant amount of toxaphene (~350 kg) being transported through the atmosphere and deposited into the Great Lakes in the simulation year. Results also show that U.S. residues and global background are major sources to toxaphene deposition into the Great Lakes and atmospheric concentrations in the region. While the U.S. residues are the dominant source in warm months, the background dominates during winter months. In addition, different sources have different influences on the individual Great Lakes due to their proximity and relative geographical positions to the sources; U.S. residues are the dominant source to Lakes Ontario, Erie, Huron, and Michigan, but they are a much less important source to Lake Superior. These results shed light on the mystery that observed toxaphene concentrations in Great Lakes' lake trout and smelt declined between 1982 and 1992 in four of the Great Lakes except Lake Superior. While monthly total depositions to Lakes Ontario, Erie, Huron, and Michigan have clear seasonal variability with much greater values in April, May, and June, monthly total depositions to Lake Superior are more uniformly distributed over the year with comparatively greater levels in cold months.

Simulating Effects of Forest Management Practices on Pesticide.

Treesearch

M.C. Smith; W.G. Knisel; J.L. Michael; D.G. Neary

1993-01-01

The GLEAMS model pesticide component was modified to simulate up to 245 pesticides simultaneously, and the revised model was used to pesticide pesticide application windows for forest site preparation and pine release. Five herbicides were made for soils representing four hydrologic soil groups in four climatic regions of the southeastern United States. Five herbicides...

Comparison of Two Parametric Methods to Estimate Pesticide Mass Loads in California's Central Valley

USGS Publications Warehouse

Saleh, D.K.; Lorenz, D.L.; Domagalski, Joseph L.

2011-01-01

Mass loadings were calculated for four pesticides in two watersheds with different land uses in the Central Valley, California, by using two parametric models: (1) the Seasonal Wave model (SeaWave), in which a pulse signal is used to describe the annual cycle of pesticide occurrence in a stream, and (2) the Sine Wave model, in which first-order Fourier series sine and cosine terms are used to simulate seasonal mass loading patterns. The models were applied to data collected during water years 1997 through 2005. The pesticides modeled were carbaryl, diazinon, metolachlor, and molinate. Results from the two models show that the ability to capture seasonal variations in pesticide concentrations was affected by pesticide use patterns and the methods by which pesticides are transported to streams. Estimated seasonal loads compared well with results from previous studies for both models. Loads estimated by the two models did not differ significantly from each other, with the exceptions of carbaryl and molinate during the precipitation season, where loads were affected by application patterns and rainfall. However, in watersheds with variable and intermittent pesticide applications, the SeaWave model is more suitable for use on the basis of its robust capability of describing seasonal variation of pesticide concentrations. ?? 2010 American Water Resources Association. This article is a US Government work and is in the public domain in the USA.

Study on the distribution of organic carbon in soil fractions and its reaction potential of binding the pesticides

NASA Astrophysics Data System (ADS)

Chowdhury, Ashim

2010-05-01

STUDY ON THE DISTRIBUTION OF ORGANIC CARBON IN SOIL FRACTIONS AND ITS REACTION POTENTIAL OF BINDING THE PESTICIDES **SUMITRA ROY1, SANKHAJIT ROY1, *ASHIM CHOWDHURY2, SASWATI PRADHAN2 and PETER BURAUEL3 1Department of Agricultural Chemicals, Bidhan Chandra Krishi Viswavidyalay, Mohanpur, West Bengal, India. 2Department of Agricultural Chemistry and Soil Science, University of Calcutta, West Bengal, India. 3Institute of Chemical Dynamics & Geosphere, FZ-Juelich, Germany. *Correspondence: ashimkly@hotmail.com **Research work carried out as DAAD Sandwich research fellow at FZ- Juelich, Germany Soil is the ultimate sink of all selectively applied pesticides. In addition to the basic physicochemical data of an active ingredient, the fate of the various compounds is largely determined by the type of application. Finally, pesticide and their metabolites, as well as structural elements, remain in the native carbon reserves of the soil or are sorbed & fixed to clay minerals and clay- humus complexes. Soil organic matter (SOM) and the soil microbial community are the crucial components which regulate soil processes and contribute towards the stability of the soil ecosystem. It is an energy source for biological mineralization processes, functions as a buffer and participates in chemical reaction. Knowledge is essential to understand the extent to which the SOM influences the mobilization and immobilization processes of foreign substance in soil and the substance transport and pollutant decomposition in soil. The freshly incorporated organic matter undergoes mineralization and the non mineralized carbon fraction is of special relevance with respect to soil stability in general and decisive for the fate and particular the persistence of xenobiotics in soil. The biological and physicochemical interactions establishing equilibrium between the organic matter bound, fixed or complexed to the soil matrix and that dissolve in the soil solution must be understood in detail to realize soil and groundwater conservation. The radio-tracer technology emerged as the latest technology in agriculture, which helps in studying the translocation of pesticide along with the organic matter and furthermore, the distribution of the pesticide in the soil phases. For the elucidation of these relationships and distribution of organic carbon in soil fractions and its reaction potential of binding the pesticides, the present laboratory study was undertaken using 14C-enriched and non labeled maize straw as a source of fresh SOM in different soil fractions vis-à-vis its effect on distribution of 14C-labeled benazolin and non labeled benazolin (a selective, post emergence herbicide) as a xenobiotics throughout the soil system. To determine the turnover of SOM fractionation of top layer of the both the benazolin treated soil column was done followed by determination of 14C content in four different soil phases obtained from fraction, characterization of different phase and identification of the metabolites with TLC, HPLC and GC-MS. The result clearly indicated that where soil columns received non- labeled maize straw and 14C-benazolin as well as 14C-labeled maize straw and nonlabeled benazolin; the unit weight distribution study of radioactivity in benazolin followed the decreasing trend in different phases in following order of electrolyte>colloidal> micro aggregate > sediment phases respectively. The percentage distribution of maize straw (fresh organic matter) was also found highest in electrolyte phase followed the same order as in the case of benazolin. It was observed in phase-wise distribution study that radioactivity either of 14C-maize straw or 14C-benazolin was mostly concentrated in the sediment phase followed by micro aggregate, colloidal and electrolyte phase. From this it was clear that the soil columns, which received maize straw, have bound the pesticide benazolin and hindered the translocation to the lower layers leading to higher percentage of recovered radioactivity at top layer. Thus, these two results can be correlated in a way that dissolve organic matter affects the mobility of the pesticide along with its own mobility.

How does land use link terrestrial and aquatic carbon in western North America?: Implications from an agricultural case study in central Montana

NASA Astrophysics Data System (ADS)

Ewing, S. A.; Sigler, W. A.

2014-12-01

The fate of soil organic matter with expanding human land use is of increasing concern for planetary health and ecological sustainability. In North American grasslands, cultivation has commonly resulted in loss of stored soil organic carbon to dissolved phases in groundwater and surface water, as well as to atmospheric CO2 via decomposition. In addition, cultivation has released nutrients stored in organic matter and facilitated water movement through soils to benefit crops, increasing groundwater recharge rates. This has altered groundwater chemistry both by changing biogeochemistry of the terrestrial-aquatic interface and by increasing addition of nutrients, herbicides, and pesticides to these systems. In this presentation, we consider the effects of food production practices on terrestrial-aquatic carbon linkages in former grassland ecosystems of western North America. Our data from an agricultural area in central Montana begin to reveal how elevated nitrate and pesticide levels in groundwater on an isolated landform reflect transformation over the last century of a temperate grassland ecosystem for wheat and cattle production. Rates and pathways of carbon and nitrogen loss are inferred from the concentration and isotopic character of both water and carbon and nitrogen over three years in soils, shallow groundwater, emergent springs and surface waters. In this semi-arid, non-irrigated context, the fate of soil organic matter is linked with redistribution of pedogenic carbonate as well as other soil and rock derived solutes. We consider implications for future trends in dissolved carbon and nitrogen in surface waters in the region.

Effects of biochars on the fate of acetochlor in soil and on its uptake in maize seedling.

PubMed

Li, Yao; Liu, Xingang; Wu, Xiaohu; Dong, Fengshou; Xu, Jun; Pan, Xinglu; Zheng, Yongquan

2018-06-12

Biochar (BC) can alter the fate and bioavailability of pesticides in soil. In this study, the effects of three types of BCs (made of crofton weed, wood chips and rice hull) on the sorption of acetochlor, a common herbicide, were investigated. The acetochlor sorption constants (K f value) were 309.96 μg 1-n L n/ kg (biochars made of ricehull, BCR), 3.54 μg 1-n L n/ kg (biochars made of crofton weed, BCH) and 2.27 μg 1-n L n/ kg (biochars made of wood chips, BCW). The persistence of acetochlor was 8 times greater when 1% BCR was added to the soil. Moreover, the half-life of acetochlor increased with increasing amounts of BC in the soil. The soil was amended with BCH (made of crofton weed) for two different aging period (10 d and 20 d) to evaluate the effects of aged BC on acetochlor accumulation in maize seedlings (Zea mays L). Amendment with 10 d-aged BCH in soil decreased the bioaccumulation of acetochlor. However, the concentrations and bioconcentration factors in maize cultivated in 20 d-aged BCH-amended soils were significantly higher than those in soil with no BCH amendments and with 10 d-aged BCH amendments. These results imply that BC aged in soil for a long period can increase the bioaccumulation of acetochlor in plants and the influences of BC on environmental risks of pesticides must be further clarified. Copyright © 2018 Elsevier Ltd. All rights reserved.

Movement and fate of creosote waste in ground water, Pensacola, Florida; U.S. Geological Survey toxic waste-ground-water contamination program

USGS Publications Warehouse

Mattraw, Harold C.; Franks, Bernard J.

1986-01-01

Ground- and surface-water contamination by pesticides used in the wood-preserving industry is widespread in the United States. Pine poles were treated with wood preservatives from 1902 to 1981 at a creosote works near Pensacola, Florida. Diesel fuel, creosote, and pentachlorophenol were discharged to two unlined impoundments that had a direct hydraulic connection to the sand-and-gravel aquifer. Evidence of wood-preserving waste contamination appears to be confined to the upper 30 meters of the aquifer. The waste plume extends downgradient approximately 300 meters south toward Pensacola Bay. In 1983, the creosote works site was selected by the U.S. Geological Survey's Office of Hazardous Waste Hydrology as a national research demonstration area to apply the latest techniques for characterizing hazardous waste problems. The multidisciplinary research effort is aimed at studying processes that affect the occurrence, transport, transformations, and fate of the toxic contaminants associated with wood preservatives in the environment. Clusters of two to five wells were constructed at different depths at nine sites to define the depth of contamination. Research studies are investigating sorption, dispersion, dilution, chemical reactions, bacterially mediated transformations, quality assurance, plume hydrodynamics, and the ultimate fate of these complex organic wastes.

A network model for the specification of vulval precursor cells and cell fusion control in Caenorhabditis elegans

PubMed Central

Weinstein, Nathan; Mendoza, Luis

2013-01-01

The vulva of Caenorhabditis elegans has been long used as an experimental model of cell differentiation and organogenesis. While it is known that the signaling cascades of Wnt, Ras/MAPK, and NOTCH interact to form a molecular network, there is no consensus regarding its precise topology and dynamical properties. We inferred the molecular network, and developed a multivalued synchronous discrete dynamic model to study its behavior. The model reproduces the patterns of activation reported for the following types of cell: vulval precursor, first fate, second fate, second fate with reversed polarity, third fate, and fusion fate. We simulated the fusion of cells, the determination of the first, second, and third fates, as well as the transition from the second to the first fate. We also used the model to simulate all possible single loss- and gain-of-function mutants, as well as some relevant double and triple mutants. Importantly, we associated most of these simulated mutants to multivulva, vulvaless, egg-laying defective, or defective polarity phenotypes. The model shows that it is necessary for RAL-1 to activate NOTCH signaling, since the repression of LIN-45 by RAL-1 would not suffice for a proper second fate determination in an environment lacking DSL ligands. We also found that the model requires the complex formed by LAG-1, LIN-12, and SEL-8 to inhibit the transcription of eff-1 in second fate cells. Our model is the largest reconstruction to date of the molecular network controlling the specification of vulval precursor cells and cell fusion control in C. elegans. According to our model, the process of fate determination in the vulval precursor cells is reversible, at least until either the cells fuse with the ventral hypoderm or divide, and therefore the cell fates must be maintained by the presence of extracellular signals. PMID:23785384

The effects of a pesticide mixture on aquatic ecosystems differing in trophic status: responses of the macrophyte Myriophyllum spicatum and the periphytic algal community.

PubMed

Wendt-Rasch, L; Van den Brink, P J; Crum, S J H; Woin, P

2004-03-01

The effects of a pesticide mixture (asulam, fluazinam, lambda-cyhalothrin, and metamitron) on aquatic ecosystems were investigated in 20 outdoor aquatic microcosms. Ten of the microcosms simulated mesotrophic aquatic ecosystems dominated by submerged macrophytes (Elodea). The others simulated eutrophic ecosystems with a high Lemna surface coverage (Lemna). This paper describes the fate of the chemicals as well as their effects on the growth of Myriophyllum spicatum and the periphytic algal community. In the Elodea-dominated microcosms significant increase in the biomass and alterations of species composition of the periphytic algae were observed, but no effect on M. spicatum growth could be recorded in response to the treatment. The opposite was found in the Lemna-dominated microcosms, in which decreased growth of M. spicatum was observed but no alterations could be found in the periphytic community. In the Elodea-dominated microcosms the species composition of the periphytic algae diverged from that of the control following treatment with 0.5% spray drift emission of the label-recommended rate (5% for lambda-cyhalothrin), while reduced growth of M. spicatum in the Lemna-dominated microcosms was recorded at 2% drift (20% for lambda-cyhalothrin). This study shows that the structure of the ecosystem influences the final effect of pesticide exposure.

Impact of soil water regime on degradation and plant uptake behaviour of the herbicide isoproturon in different soil types.

PubMed

Grundmann, Sabine; Doerfler, Ulrike; Munch, Jean Charles; Ruth, Bernhard; Schroll, Reiner

2011-03-01

The environmental fate of the worldwide used herbicide isoproturon was studied in four different, undisturbed lysimeters in the temperate zone of Middle Europe. To exclude climatic effects due to location, soils were collected at different regions in southern Germany and analyzed at a lysimeter station under identical environmental conditions. (14)C-isoproturon mineralization varied between 2.59% and 57.95% in the different soils. Barley plants grown on these lysimeters accumulated (14)C-pesticide residues from soil in partially high amounts and emitted (14)CO(2) in an extent between 2.01% and 13.65% of the applied (14)C-pesticide. Plant uptake and (14)CO(2) emissions from plants were inversely linked to the mineralization of the pesticide in the various soils: High isoproturon mineralization in soil resulted in low plant uptake whereas low isoproturon mineralization in soil resulted in high uptake of isoproturon residues in crop plants and high (14)CO(2) emission from plant surfaces. The soil water regime was identified as an essential factor that regulates degradation and plant uptake of isoproturon whereby the intensity of the impact of this factor is strongly dependent on the soil type. Copyright © 2010 Elsevier Ltd. All rights reserved.

Modelling pesticide volatilization after soil application using the mechanistic model Volt'Air

NASA Astrophysics Data System (ADS)

Bedos, Carole; Génermont, Sophie; Le Cadre, Edith; Garcia, Lucas; Barriuso, Enrique; Cellier, Pierre

Volatilization of pesticides participates in atmospheric contamination and affects environmental ecosystems including human welfare. Modelling at relevant time and spatial scales is needed to better understand the complex processes involved in pesticide volatilization. Volt'Air-Pesticides has been developed following a two-step procedure to study pesticide volatilization at the field scale and at a quarter time step. Firstly, Volt'Air-NH 3 was adapted by extending the initial transfer of solutes to pesticides and by adding specific calculations for physico-chemical equilibriums as well as for the degradation of pesticides in soil. Secondly, the model was evaluated in terms of 3 pesticides applied on bare soil (atrazine, alachlor, and trifluralin) which display a wide range of volatilization rates. A sensitivity analysis confirmed the relevance of tuning to K h. Then, using Volt'Air-Pesticides, environmental conditions and emission fluxes of the pesticides were compared to fluxes measured under 2 environmental conditions. The model fairly well described water temporal dynamics, soil surface temperature, and energy budget. Overall, Volt'Air-Pesticides estimates of the order of magnitude of the volatilization flux of all three compounds were in good agreement with the field measurements. The model also satisfactorily simulated the decrease in the volatilization rate of the three pesticides during night-time as well as the decrease in the soil surface residue of trifluralin before and after incorporation. However, the timing of the maximum flux rate during the day was not correctly described, thought to be linked to an increased adsorption under dry soil conditions. Thanks to Volt'Air's capacity to deal with pedo-climatic conditions, several existing parameterizations describing adsorption as a function of soil water content could be tested. However, this point requires further investigation. Practically speaking, Volt'Air-Pesticides can be a useful tool to make decision about agricultural practices such as incorporation or for the estimation of overall pesticide volatilization rates, and it holds promise for time specific dynamics.

Water Quality and Evaluation of Pesticides in Lakes in the Ridge Citrus Region of Central Florida

USGS Publications Warehouse

Choquette, Anne F.; Kroening, Sharon E.

2009-01-01

Water chemistry, including major inorganic constituents, nutrients, and pesticide compounds, was compared between seven lakes surrounded by citrus agriculture and an undeveloped lake on the Lake Wales Ridge (herein referred to as the Ridge) in central Florida. The region has been recognized for its vulnerability to the leaching of agricultural chemicals into the subsurface due to factors including soils, climate, and land use. About 40 percent of Florida's citrus cultivation occurs in 'ridge citrus' areas characterized by sandy well drained soils, with the remainder in 'flatwoods citrus' characterized by high water tables and poorly drained soils. The lakes on the Ridge are typically flow-through lakes that exchange water with adjacent and underlying aquifer systems. This study is the first to evaluate the occurrence of pesticides in lakes on the Ridge, and also represents one of the first monitoring efforts nationally to focus on regional-scale assessment of current-use pesticides in small- to moderate-sized lakes (5 to 393 acres). The samples were collected between December 2003 and September 2005. The lakes in citrus areas contained elevated concentrations of major inorganic constituents (including alkalinity, total dissolved solids, calcium, magnesium, sodium, potassium, chloride, and sulfate), total nitrogen, pH, and pesticides compared to the undeveloped lake. Nitrate (as N) and total nitrogen concentrations were typically elevated in the citrus lakes, with maximum values of 4.70 and 5.19 mg/L (milligrams per liter), respectively. Elevated concentrations of potassium, nitrate, and other inorganic constituents in the citrus lakes likely reflect inputs from the surficial ground-water system that originated predominantly from agricultural fertilizers, soil amendments, and inorganic pesticides. A total of 20 pesticide compounds were detected in the lakes, of which 12 compounds exceeded the standardized reporting level of 0.06 ug/L (microgram per liter). Those most frequently detected above the 0.06-ug/L level were aldicarb sulfoxide, diuron, simazine degradates hydroxysimazine and didealkylatrazine (DDA), bromacil, norflurazon, and demethyl norflurazon which occurred at detection rates ranging from 25 to 86 percent of samples, respectively. Typically, pesticide concentrations in the lake samples were less than 1 microgram per liter. The number of targeted pesticide compounds detected per lake in the citrus areas ranged from 9 to 14 compared to 3 compounds detected at trace levels in the undeveloped lake. Consistent detections of parents and degradates in quarterly samples indicated the presence of pesticide compounds in the lakes many months or years (for example, bromacil) after their application, signaling the persistence of some pesticide compounds in the lakes and/or ground-water systems. Pesticide degradate concentrations frequently exceeded parent concentrations in the lakes. This study was the first in the Ridge citrus region to analyze for glyphosate - widely used in citrus - and its degradate aminomethylphosphonic acid (AMPA), neither of which were detected, as well as a number of triazine degradates, including hydroxysimazine, which were detected. The lake pesticide concentrations did not exceed current Federal aquatic-life benchmarks, available for 10 of the 20 detected pesticide compounds. Limited occurrences of bromacil, diuron, or norflurazon concentrations were within about 10 to 90 percent of benchmark guidelines for acute effects on nonvascular aquatic plants in one or two of the lakes. The lake pesticide concentrations for several targeted pesticides were relatively high compared to corresponding national stream-water percentiles, which is consistent with this region's vulnerability for pesticide leaching into water resources. Several factors were evaluated to gain insight into the processes controlling pesticide transport and fate, and to assess their utility for estimating th

Implementation of the effects of physicochemical properties on the foliar penetration of pesticides and its potential for estimating pesticide volatilization from plants.

PubMed

Lichiheb, Nebila; Personne, Erwan; Bedos, Carole; Van den Berg, Frederik; Barriuso, Enrique

2016-04-15

Volatilization from plant foliage is known to have a great contribution to pesticide emission to the atmosphere. However, its estimation is still difficult because of our poor understanding of processes occurring at the leaf surface. A compartmental approach for dissipation processes of pesticides applied on the leaf surface was developed on the base of experimental study performed under controlled conditions using laboratory volatilization chamber. This approach was combined with physicochemical properties of pesticides and was implemented in SURFATM-Pesticides model in order to predict pesticide volatilization from plants in a more mechanistic way. The new version of SURFATM-Pesticide model takes into account the effect of formulation on volatilization and leaf penetration. The model was evaluated in terms of 3 pesticides applied on plants at the field scale (chlorothalonil, fenpropidin and parathion) which display a wide range of volatilization rates. The comparison of modeled volatilization fluxes with measured ones shows an overall good agreement for the three tested compounds. Furthermore the model confirms the considerable effect of the formulation on the rate of the decline in volatilization fluxes especially for systemic products. However, due to the lack of published information on the substances in the formulations, factors accounting for the effect of formulation are described empirically. A sensitivity analysis shows that in addition to vapor pressure, the octanol-water partition coefficient represents important physicochemical properties of pesticides affecting pesticide volatilization from plants. Finally the new version of SURFATM-Pesticides is a prospecting tool for key processes involved in the description of pesticide volatilization from plants. Copyright © 2016 Elsevier B.V. All rights reserved.

Fungicide dissipation and impact on metolachlor aerobic soil degradation and soil microbial dynamics.

PubMed

White, Paul M; Potter, Thomas L; Culbreath, Albert K

2010-02-15

Pesticides are typically applied as mixtures and or sequentially to soil and plants during crop production. A common scenario is herbicide application at planting followed by sequential fungicide applications post-emergence. Fungicides depending on their spectrum of activity may alter and impact soil microbial communities. Thus there is a potential to impact soil processes responsible for herbicide degradation. This may change herbicide efficacy and environmental fate characteristics. Our study objective was to determine the effects of 4 peanut fungicides, chlorothalonil (2,4,5,6-tetrachloro-1,3-benzenedicarbonitrile), tebuconazole (alpha-[2-(4-chlorophenyl)ethyl]-alpha-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol), flutriafol (alpha-(2-fluorophenyl)-alpha-(4-fluorophenyl)-1H-1,2,4-triazole-1-ethanol), and cyproconazole (alpha-(4-chlorophenyl)-alpha-(1-cyclopropylethyl)-1H-1,2,4-triazole-1-ethanol) on the dissipation kinetics of the herbicide, metolachlor (2-chloro-N-(6-ethyl-o-tolyl)-N-[(1RS)-2-methoxy-1-methylethyl]acetamide), and on the soil microbial community. This was done through laboratory incubation of field treated soil. Chlorothalonil significantly reduced metolachlor soil dissipation as compared to the non-treated control or soil treated with the other fungicides. Metolachlor DT(50) was 99 days for chlorothalonil-treated soil and 56, 45, 53, and 46 days for control, tebuconazole, flutriafol, and cyproconazole-treated soils, respectively. Significant reductions in predominant metolachlor metabolites, metolachlor ethane sulfonic acid (MESA) and metolachlor oxanilic acid (MOA), produced by oxidation of glutathione-metolachlor conjugates were also observed in chlorothalonil-treated soil. This suggested that the fungicide impacted soil glutathione-S-transferase (GST) activity. Fungicide DT(50) was 27-80 days but impacts on the soil microbial community as indicated by lipid biomarker analysis were minimal. Overall study results indicated that chlorothalonil has the potential to substantially increase soil persistence (2-fold) of metolachlor and alter fate and transport processes. GST mediated metabolism is common pesticide detoxification process in soil; thus there are implications for the fate of many active ingredients.

Fate of Organohalogens in U.S. Wastewater Treatment Plants and Estimated Chemical Releases to Soils Nationwide from Biosolids Recycling

PubMed Central

Heidler, Jochen; Halden, Rolf U.

2009-01-01

This study examined the occurrence in wastewater of 11 aromatic biocides, pesticides and degradates, and their fate during passage through U.S. treatment plants, as well as the chemical mass contained in sewage sludge (biosolids) destined for land application. Analyte concentrations in wastewater influent, effluent and sludge from 25 facilities in 18 U.S. states were determined by liquid chromatography electrospray (tandem) mass spectrometry. Dichlorocarbanilide, fipronil, triclocarban, and triclosan were found consistently in all sample types. Dichlorophene, hexachlorophene, and tetrachlorocarbanilide were detected infrequently only, and concentrations of the phenyl urea pesticides diflubenzuron, hexaflumuron, and linuron were below the limit of detection in all matrixes. Median concentrations (± 95% confidence interval) of quantifiable compounds in influent ranged from 4.2 ± 0.8 µg L−1 for triclocarban to 0.03 ± 0.01 µg L−1 for fipronil. Median concentrations in effluent were highest for triclocarban and triclosan (0.23 ± 0.08 and 0.07 ± 0.04 µg L−1, respectively). Median aqueous-phase removal efficiencies (± 95% CI) of activated sludge treatment plants decreased in the order of: triclosan (96 ± 2%) > triclocarban (87 ± 7%) > dichlorocarbanilide (55 ± 20%) > fipronil (18 ± 22%). Median concentrations of organohalogens were typically higher in anaerobically than in aerobically digested sludges, and peaked at 27,600 ± 9,600 and 15,800 ± 8,200 µg kg−1 for triclocarban and triclosan, respectively. Mass balances obtained for three primary pesticides in six activated sludge treatment plants employing anaerobic digestion suggested a decreasing overall persistence from fipronil (97 ± 70%) to triclocarban (87 ± 29%) to triclosan (28 ± 30%). Nationwide release of the investigated organohalogens to agricultural land via municipal sludge recycling and into surface waters is estimated to total 258,000 ± 110,00 kg yr−1 (mean ± 95% confidence interval), with most of this mass derived from antimicrobial consumer products of daily use. This study addresses some of the data gaps identified by the National Research Council in its 2002 study on standards and practices of biosolids application on land. PMID:20024018

DIETARY EXPOSURES OF YOUNG CHILDREN, PART 3: MODELLING

EPA Science Inventory

A deterministic model was used to model dietary exposure of young children. Parameters included pesticide residue on food before handling, surface pesticide loading, transfer efficiencies and children's activity patterns. Three components of dietary pesticide exposure were includ...

Improving the consideration of hydrogeological characteristics to assess the contamination groundwater by pesticides at national scale (France)

NASA Astrophysics Data System (ADS)

Auterives, Chrystelle; Baran, Nicole; Surdyk, Nicolas

2017-04-01

According to the European Water Framework Directive, Member States have to conduct study of anthropogenic pressure and its impact on the status of water bodies, and to implement programs of measures in order to reverse any significant and sustained upward trend in the concentration of any pollutant. Focused on pesticides in groundwater, the aim of this work is to propose new tools to the stakeholders to identifying groundwater bodies presenting a risk of not achieving « good chemical status ». Several parameters control the transfer of a pesticide from the soil to the groundwater: climate conditions (i.e. recharge), soil and hydrogeological characteristics, pesticides physico-chemical properties. The issues of this study are (1) to take account of hydrogeology context, besides soil and pesticide physico-chemical properties relatively well studied as in registration procedure; (2) to work at national scale which involve to consider variability of land uses and practices, (hydro)geology and climate conditions. To overcome difficulties, this study proposes to identify, when data make it possible, the main driver (hydrogeology or pesticides properties) which explains transfer of pesticides into groundwater at the water body scale. This aspect is particularly innovative as, to date, hydrogeology contexts are usually not considered. Thus, for instance, timeframe of transfer in the unsaturated zone is also considered. Despite work being performed for several substances with contrasted physico-chemical properties, the outcome will be a classification of substances in different groups according to their chemical properties and their potential occurrence in groundwater. The work is based on existing data only. From French databases, BNVD (French national database of the sales of pesticides) and ADES (national French data base on groundwater resources gathering), we are able to link pesticides use and groundwater impact. As a first step, several specific pesticides were selected as study case and lead to distinguish groundwater bodies as: - Groundwater bodies where pressure cannot be evaluated ; - Groundwater bodies with no pressure (sale) ; - Groundwater bodies where pressure (sale) lead to an impact (quantification of the specific substance) ; - Groundwater bodies where there is a pressure (sale) but no impact which means (1) geological conditions offer a natural protection of groundwater quality or (2) the transfer time into groundwater is longer than the observation period or (3) the fate of pesticides lead to a limited transfer. From the different maps and the pesticides studied, final results would be to classify groundwater bodies as: - The main driver is hydrogeology: whatever the substance i.e. whatever the pesticide properties, impacts on groundwater quality are similar. Either, geological conditions protect the groundwater resources, pesticides do not transfer to groundwater or, there is no natural protection, whatever the substance, it transfers to groundwater. - Geological conditions are not the main driver but the pesticide properties do. Therefore, depending on pesticides physico-chemical properties, substances will transfer to groundwater or not. A classification of substances in several groups according there properties (DT50 and Koc) will be performed. The main expected outcome of this project is the establishment of methodology of characterization of the link between pressure and impact, at national scale. Final results would provide operational tools to the stakeholders to go further in the pressure and impact analysis of the pesticide in groundwater to improve the risk evaluation and adapt program of measures to reach the "good chemical status" of groundwater bodies.

Pesticide poisoning and respiratory disorders in Colorado farm residents.

PubMed

Beseler, C L; Stallones, L

2009-10-01

Respiratory hazards significantly contribute to the burden of occupational disease among farmers. Pesticide exposure has been linked to an increased prevalence of respiratory symptoms in several farming populations. The purpose of this study was to evaluate the association between respiratory symptoms and pesticide poisoning in a cross-sectional survey of farm residents. A total of 761 farm operators and their spouses, representing 479 farms in northeastern Colorado, were recruited from 1993 to 1997. A personal interview asked whether the resident had experienced a pesticide poisoning and several respiratory conditions including cough, allergy, wheeze, and organic dust toxic syndrome (ODTS). Spirometry testing was performed on 196 individuals. Logistic regression was used to model the association of pesticide poisoning with respiratory conditions, and linear regression was used to model the relationship of pesticide poisoning and forced vital capacity (FVC) and forced expiratory volume (FEV1). In unadjusted models, pesticide poisoning was associated with all four respiratory conditions, and stayed significant in adjusted models of allergies and cough in non-smokers. In age- and gender-adjusted models, pesticide poisoning was significantly associated with lower FVC and FEV1 in current smokers and in those who were not heavy drinkers. Although this study should be reproduced in a larger sample, it suggests that further evaluation of the respiratory effects of pesticide exposure is warranted.

FATE 5: A natural attenuation calibration tool for groundwater fate and transport modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nevin, J.P.; Connor, J.A.; Newell, C.J.

1997-12-31

A new groundwater attenuation modeling tool (FATE 5) has been developed to assist users with determining site-specific natural attenuation rates for organic constituents dissolved in groundwater. FATE 5 is based on and represents an enhancement to the Domenico analytical groundwater transport model. These enhancements include use of an optimization routine to match results from the Domenico model to actual measured site concentrations, an extensive database of chemical property data, and calculation of an estimate of the length of time needed for a plume to reach steady state conditions. FATE 5 was developed in Microsoft{reg_sign} Excel and is controlled by meansmore » of a simple, user-friendly graphical interface. Using the Solver routine built into Excel, FATE 5 is able to calibrate the attenuation rate used by the Domenico model to match site-specific data. By calibrating the decay rate to site-specific measurements, FATE 5 can yield accurate predictions of long-term natural attenuation processes within a groundwater within a groundwater plume. In addition, FATE 5 includes a formulation of the transient Domenico solution used to help the user determine if the steady-state assumptions employed by the model are appropriate. The calibrated groundwater flow model can then be used either to (i) predict upper-bound constituent concentrations in groundwater, based on an observed source zone concentration, or (ii) back-calculate a lower-bound SSTL value, based on a user-specified exposure point concentration at the groundwater point of exposure (POE). This paper reviews the major elements of the FATE 5 model - and gives results for real-world applications. Key modeling assumptions and summary guidelines regarding calculation procedures and input parameter selection are also addressed.« less

Stochastic Human Exposure and Dose Simulation Model for Pesticides

EPA Science Inventory

SHEDS-Pesticides (Stochastic Human Exposure and Dose Simulation Model for Pesticides) is a physically-based stochastic model developed to quantify exposure and dose of humans to multimedia, multipathway pollutants. Probabilistic inputs are combined in physical/mechanistic algorit...

Modeling spray drift and runoff-related inputs of pesticides to receiving water.

PubMed

Zhang, Xuyang; Luo, Yuzhou; Goh, Kean S

2018-03-01

Pesticides move to surface water via various pathways including surface runoff, spray drift and subsurface flow. Little is known about the relative contributions of surface runoff and spray drift in agricultural watersheds. This study develops a modeling framework to address the contribution of spray drift to the total loadings of pesticides in receiving water bodies. The modeling framework consists of a GIS module for identifying drift potential, the AgDRIFT model for simulating spray drift, and the Soil and Water Assessment Tool (SWAT) for simulating various hydrological and landscape processes including surface runoff and transport of pesticides. The modeling framework was applied on the Orestimba Creek Watershed, California. Monitoring data collected from daily samples were used for model evaluation. Pesticide mass deposition on the Orestimba Creek ranged from 0.08 to 6.09% of applied mass. Monitoring data suggests that surface runoff was the major pathway for pesticide entering water bodies, accounting for 76% of the annual loading; the rest 24% from spray drift. The results from the modeling framework showed 81 and 19%, respectively, for runoff and spray drift. Spray drift contributed over half of the mass loading during summer months. The slightly lower spray drift contribution as predicted by the modeling framework was mainly due to SWAT's under-prediction of pesticide mass loading during summer and over-prediction of the loading during winter. Although model simulations were associated with various sources of uncertainties, the overall performance of the modeling framework was satisfactory as evaluated by multiple statistics: for simulation of daily flow, the Nash-Sutcliffe Efficiency Coefficient (NSE) ranged from 0.61 to 0.74 and the percent bias (PBIAS) < 28%; for daily pesticide loading, NSE = 0.18 and PBIAS = -1.6%. This modeling framework will be useful for assessing the relative exposure from pesticides related to spray drift and runoff in receiving waters and the design of management practices for mitigating pesticide exposure within a watershed. Published by Elsevier Ltd.

Superabsorbent hydrogels coating increased degradation and decreased bound residues formation of carbendazim in soil.

PubMed

Yang, Yatian; Zhang, Sufen; Yang, Jingying; Bai, Chan; Tang, Shenghua; Ye, Qingfu; Wang, Haiyan

2018-07-15

The intensive use of pesticides has caused serious environmental pollution and ecological issues. Thus, it is imperative to explore an efficient way to minimize the pesticide residues and pollution. In the present study, we employed the superabsorbent hydrogels (SHs)-coated pesticide 14 C-carbendazim (H- 14 C-MBC) to investigate the fate of MBC in aerobic soils and to assess the soil microbial state during incubation. The results showed that after coating with SHs, MBC dissipation was improved significantly by 34.2-54.1% compared with that in the control (p<0.05), reducing the persistence of MBC in soil matrix. At 100d, the release of 14 C-CO 2 was enhanced by 68.0% and 46.6% in neutral loamy soil and basic saline soil, respectively, with respect to the control, resulting in more complete degradation and detoxification of MBC. Additionally, the bound residue in soils, which was associated with potential environmental risk and pollution, was reduced by 15.2% and 14.2%, respectively, compared with that in control soils. The microbial diversity of post-H- 14 C-MBC soil varied, and microbial composition and abundance remained different from the control, even with the refreshment of soil stability and fertility compared with the blank soil. These results demonstrate the environmental behavior of SHs-coated MBC in soils, and illustrate that SHs-encapsulated formulations would be a promising measure for reducing the soil-residue pollution and environmental risk of pesticides. Copyright © 2018 Elsevier B.V. All rights reserved.

Enhanced degradation and soil depth effects on the fate of atrazine and major metabolites in Colorado and Mississippi soils.

PubMed

Krutz, L Jason; Shaner, Dale L; Zablotowicz, Robert M

2010-01-01

The aim of this report is to inform modelers of the differences in atrazine fate between s-triazine-adapted and nonadapted soils as a function of depth in the profile and to recommend atrazine and metabolite input values for pesticide process submodules. The objectives of this study were to estimate the atrazine-mineralizing bacterial population, cumulative atrazine mineralization, atrazine persistence, and metabolite (desethylatrazine [DEA], deisopropylatrazine [DIA], and hydroxyatrazine [HA]) formation and degradation in Colorado and Mississippi s-triazine-adapted and nonadapted soils at three depths (0-5, 5-15, and 15-30 cm). Regardless of depth, the AMBP and cumulative atrazine mineralization was at least 3.8-fold higher in s-triazine-adapted than nonadapted soils. Atrazine half-life (T1/2) values pooled over nonadapted soils and depths approximated historic estimates (T1/2 = 60 d). Atrazine persistence in all depths of s-triazine-adapted soils was at least fourfold lower than that of the nonadapted soil. Atrazine metabolite concentrations were lower in s-triazine-adapted than in nonadapted soil by 35 d after incubation regardless of depth. Results indicate that (i) reasonable fate and transport modeling of atrazine will require identifying if soils are adapted to s-triazine herbicides. For example, our data confirm the 60-d T1/2 for atrazine in nonadapted soils, but a default input value of 6 d for atrazine is required for s-triazine adapted soils. (ii) Literature estimates for DEA, DIA, and HA T1/2 values in nonadapted soils are 52, 36, and 60 d, respectively, whereas our analysis indicates that reasonable T1/2 values for s-triazine-adapted soils are 10 d for DEA, 8 d for DIA, and 6 d for HA. (iii) An estimate for the relative distribution of DIA, DEA, and HA produced in nonadapted soils is 18, 72, and 10% of parent, respectively. In s-triazine-adapted soils, the values were 6, 23, and 71% for DIA, DEA, and HA, respectively. The effects of soil adaptation on metabolite distribution need to be confirmed in field experiments.

Spatially distributed environmental fate modelling of terbuthylazine in a mesoscale agricultural catchment using passive sampler data

NASA Astrophysics Data System (ADS)

Gassmann, Matthias; Farlin, Julien; Gallé, Tom

2017-04-01

Agricultural application of herbicides often leads to significant herbicide losses to receiving rivers. The impact of agricultural practices on water pollution can be assessed by process-based reactive transport modelling using catchment scale models. Prior to investigations of management practices, these models have to be calibrated using sampling data. However, most previous studies only used concentrations at the catchment outlet for model calibration and validation. Thus, even if the applied model is spatially distributed, predicted spatial differences of pesticide loss cannot be directly compared to observations. In this study, we applied the spatially distributed reactive transport model Zin-AgriTra in the mesoscale (78 km2) catchment of the Wark River in Luxembourg in order to simulate concentrations of terbuthylazine in river water. In contrast to former studies, we used six sampling points, equipped with passive samplers, for pesticide model validation. Three samplers were located in the main channel of the river and three in smaller tributaries. At each sampling point, event mean concentration of six events from May to July 2011 were calculated by subtraction of baseflow-mass from total collected mass assuming time-proportional uptake by passive samplers. Continuous discharge measurements and high-resolution autosampling during events allowed for accurate load calculations at the outlet. Detailed information about maize cultivation in the catchment and nation-wide terbuthylazine application statistics (341 g/ha in the 3rd week of May) were used for a definition of the pesticide input function of the model. The hydrological model was manually calibrated to fit baseflow and spring/summer events. Substance fluxes were calibrated using a Latin Hypercube of physico-chemical substance characteristics as provided by the literature: surface soil half-lives of 10-35 d, Freundlich KOC of 150-330 ml/g, Freundlich n of 0.9 - 1 and adsorption/desorption kinetics of 20 - 80 1/d. Daily discharge simulations resulted in high Kling-Gupta efficiencies (KGE) for the calibration and the validation period (KGE > 0.70). Overall, terbuthylazine concentrations could be successfully reproduced with maximum KGE > 0.90 for all concentrations in the catchment and loads at the outlet. The generally lower concentrations in the tributaries that were measured by the passive samplers and the declining concentrations towards the outlet in the main channel could be reproduced by the model. The model simulated overland flow to be the major source of terbuthylazine in the main channel and soil water fluxes to be the most important pathways in the tributaries. Simulation results suggest that less than 0.01 % of applied terbuthylazine mass was exported to the river in the Wark catchment and less than 5 % of the exported mass was originating from the sampled tributaries. In addition to calibration of substance characteristics, passive sampler data was helpful in model setup of application field connectivity. Since the spatial resolution of the model was 50m, input maps sometimes showed a field to be directly connected to a river, whereas it was in reality separated from it by a 30m wide field or forest strip. Such misconfigurations leading to high concentrations in tributaries could easily be identified by comparing model results to passive sampler data. In conclusion, assigning different transport pathways of terbuthylazine to the rivers by model simulations was helped by using the additional spatial information on pesticide concentrations gained from passive samplers.

Pesticide Environmental Accounting: a method for assessing the external costs of individual pesticide applications.

PubMed

Leach, A W; Mumford, J D

2008-01-01

The Pesticide Environmental Accounting (PEA) tool provides a monetary estimate of environmental and health impacts per hectare-application for any pesticide. The model combines the Environmental Impact Quotient method and a methodology for absolute estimates of external pesticide costs in UK, USA and Germany. For many countries resources are not available for intensive assessments of external pesticide costs. The model converts external costs of a pesticide in the UK, USA and Germany to Mediterranean countries. Economic and policy applications include estimating impacts of pesticide reduction policies or benefits from technologies replacing pesticides, such as sterile insect technique. The system integrates disparate data and approaches into a single logical method. The assumptions in the system provide transparency and consistency but at the cost of some specificity and precision, a reasonable trade-off for a method that provides both comparative estimates of pesticide impacts and area-based assessments of absolute impacts.

Hydrological and pesticide transfer modeling in a tropical volcanic watershed with the WATPPASS model

NASA Astrophysics Data System (ADS)

Mottes, Charles; Lesueur-Jannoyer, Magalie; Charlier, Jean-Baptiste; Carles, Céline; Guéné, Mathilde; Le Bail, Marianne; Malézieux, Eric

2015-10-01

Simulation of flows and pollutant transfers in heterogeneous media is widely recognized to be a remaining frontier in hydrology research. We present a new modeling approach to simulate agricultural pollutions in watersheds: WATPPASS, a model for Watershed Agricultural Techniques and Pesticide Practices ASSessment. It is designed to assess mean pesticide concentrations and loads that result from the use of pesticides in horticultural watersheds located on heterogeneous subsoil. WATPPASS is suited for small watershed with significant groundwater flows and complex aquifer systems. The model segments the watershed into fields with independent hydrological and pesticide transfers at the ground surface. Infiltrated water and pesticides are routed toward outlet using a conceptual reservoir model. We applied WATPPASS on a heterogeneous tropical volcanic watershed of Martinique in the French West Indies. We carried out and hydrological analysis that defined modeling constraints: (i) a spatial variability of runoff/infiltration partitioning according to land use, and (ii) a predominance of groundwater flow paths in two overlapping aquifers under permeable soils (50-60% of annual flows). We carried out simulations on a 550 days period at a daily time step for hydrology (Nashsqrt > 0.75). Weekly concentrations and loads of a persistent organic pesticide (chlordecone) were simulated for 67 weeks to evaluate the modeling approach. Pesticide simulations without specific calibration detected the mean long-term measured concentration, leading to a good quantification of the cumulative loads (5% error), but failed to represent the concentration peaks at the correct timing. Nevertheless, we succeed in adjusting the model structure to better represent the temporal dynamic of pesticide concentrations. This modification requires a proper evaluation on an independent dataset. Finally, WATPPASS is a compromise between complexity and easiness of use that makes it suited for cropping system assessment in complex pedological and geological environment.

Non-animal approaches for toxicokinetics in risk evaluations of food chemicals.

PubMed

Punt, Ans; Peijnenburg, Ad A C M; Hoogenboom, Ron L A P; Bouwmeester, Hans

2017-01-01

The objective of the present work was to review the availability and predictive value of non-animal toxicokinetic approaches and to evaluate their current use in European risk evaluations of food contaminants, additives and food contact materials, as well as pesticides and medicines. Results revealed little use of quantitative animal or human kinetic data in risk evaluations of food chemicals, compared with pesticides and medicines. Risk evaluations of medicines provided sufficient in vivo kinetic data from different species to evaluate the predictive value of animal kinetic data for humans. These data showed a relatively poor correlation between the in vivo bioavailability in rats and dogs versus that in humans. In contrast, in vitro (human) kinetic data have been demonstrated to provide adequate predictions of the fate of compounds in humans, using appropriate in vitro-in vivo scalers and by integration of in vitro kinetic data with in silico kinetic modelling. Even though in vitro kinetic data were found to be occasionally included within risk evaluations of food chemicals, particularly results from Caco-2 absorption experiments and in vitro data on gut-microbial conversions, only minor use of in vitro methods for metabolism and quantitative in vitro-in vivo extrapolation methods was identified. Yet, such quantitative predictions are essential in the development of alternatives to animal testing as well as to increase human relevance of toxicological risk evaluations. Future research should aim at further improving and validating quantitative alternative methods for kinetics, thereby increasing regulatory acceptance of non-animal kinetic data.

Influence of climate and land use change on spatially resolved volatilization of persistent organic pollutants (POPs) from background soils.

PubMed

Komprda, Jiří; Komprdová, Klára; Sáňka, Milan; Možný, Martin; Nizzetto, Luca

2013-07-02

The subject of this study is the assessment of the influence of climate and land use change on the potential re-emission of organochlorine pesticides (OCPs) from background and agricultural soils. A deterministic spatially and temporally explicit model of the air-surface exchange was created, fed with distributed data of soil and atmospheric concentrations from real measurements, and run under various scenarios of temperature and land use change for a case study area representative of central European conditions. To describe land use influence, some important features were implemented including effect of plowing, influence of land cover, temperature of soil, and seasonal changes of air layer stability. Results show that volatilization of pesticides from soil largely exceeded dry gas deposition in most of the area. Agricultural soils accounted for more than 90% of the total re-emissions both because of the generally higher soil fugacities (higher loads of chemicals and relatively low organic carbon content), but also due to physical characteristics and land management practices enhancing the dynamics of the exchange. An increase of 1 °C in air temperature produced an increase of 8% in the averaged total volatilization flux, however this effect can be neutralized by a change of land use of 10% of the arable lands to grassland or forest, which is consistent with projected land use change in Europe. This suggests that future assessment of climate impact on POP fate and distribution should take into consideration land use aspects.

A Mercury Transport and Fate Model for Mass Budget Assessment of Mercury Cycling in Lake Michigan

EPA Science Inventory

A mercury mass balance model was developed to describe and evaluate the fate, transport, and biogeochemical transformations of mercury in Lake Michigan. Coupling with total suspendable solids (TSS) and dissolved organic carbon (DOC), the mercury transport and fate model simulates...

Pesticide uptake in potatoes: model and field experiments.

PubMed

Juraske, Ronnie; Vivas, Carmen S Mosquera; Velásquez, Alexander Erazo; Santos, Glenda García; Moreno, Mónica B Berdugo; Gomez, Jaime Diaz; Binder, Claudia R; Hellweg, Stefanie; Dallos, Jairo A Guerrero

2011-01-15

A dynamic model for uptake of pesticides in potatoes is presented and evaluated with measurements performed within a field trial in the region of Boyacá, Colombia. The model takes into account the time between pesticide applications and harvest, the time between harvest and consumption, the amount of spray deposition on soil surface, mobility and degradation of pesticide in soil, diffusive uptake and persistence due to crop growth and metabolism in plant material, and loss due to food processing. Food processing steps included were cleaning, washing, storing, and cooking. Pesticide concentrations were measured periodically in soil and potato samples from the beginning of tuber formation until harvest. The model was able to predict the magnitude and temporal profile of the experimentally derived pesticide concentrations well, with all measurements falling within the 90% confidence interval. The fraction of chlorpyrifos applied on the field during plant cultivation that eventually is ingested by the consumer is on average 10(-4)-10(-7), depending on the time between pesticide application and ingestion and the processing step considered.

Phototransformation of the herbicide sulcotrione on maize cuticular wax.

PubMed

Ter Halle, Alexandra; Drncova, Daniela; Richard, Claire

2006-05-01

Vegetation plays a key role in environmental cycling and the fate of many organic pollutants. This is especially the case for pesticides because plant leaves are their first reaction environment after application. It is commonly accepted that photochemical reactions of pollutants on plants predominantly take place in the cuticular wax coating of the leaves. Thus, we used films made of either cuticular wax extracted from maize or carnauba gray wax as a model support. Under simulated sunlight irradiation, sulcotrione (a new class of triketone herbicides) sorbed on cuticular wax films was photolyzed and mainly underwent an intramolecular cyclization. The photoproduct is a chromone derivative which was isolated and fully characterized. It is reported for the first time as a sulcotrione degradation product. The photoreactivity of formulated sulcotrione at the surface of cuticular waxes was investigated too. It photodegraded more rapidly than nonformulated sulcotrione. This study also shows that the rate of sulcotrione photolysis was much faster than the rate of penetration into the wax; photolysis should be, thus, a relevant process in real conditions.

Sources and Fate of Chiral Organochlorine Pesticides in Western U.S. National Park Ecosystems

PubMed Central

Genualdi, Susan A.; Hageman, Kimberly J.; Ackerman, Luke K.; Usenko, Sascha; Simonich, Staci L. Massey

2011-01-01

The enantiomer fractions (EFs) of alpha-hexachlorocyclohexane (α-HCH), cis-, trans-, and oxychlordane, and heptachlor epoxide were measured in 73 snow, fish, and sediment samples collected from remote lake catchments, over a wide range of latitudes, in seven western U.S. National Parks/Preserves in order to investigate their sources, fate, accumulation and biotransformation in these ecosystems. The present study is novel because these lakes had no inflow or outflow and the measurement of chiral organochlorine pesticides (OCPs) EFs in snowpack from these lake catchments provided a better understanding of the OCP sources in the Western U.S., while their measurement in fish and sediment provided a better understanding of their biotic transformations within the lake catchments. Non-racemic α-HCH was measured in seasonal snowpack collected from continental U.S. National Parks, while racemic α-HCH was measured in seasonal snowpack collected from the Alaskan parks, suggesting the influence of regional sources to the continental U.S. parks and long-range sources to the Alaskan parks. The α-HCH EFs measured in trout collected from the lake catchments were similar to the α-HCH EFs measured in seasonal snowpack collected from the same lake catchments, suggesting that these fish did not biotransform α-HCH enantioselectively. Racemic cis-chlordane was measured in seasonal snowpack and sediment collected from Sequoia, indicating that it had not undergone significant enantioselective biotransformation in urban soils since its use as a termiticide in the surrounding urban areas. However, non-racemic cis-chlordane was measured in seasonal snowpack and sediments from Rocky Mountain, suggesting cis-chlordane does undergo enantioselective biotransformation in agricultural soils. The trout from these lakes showed preferential biotransformation of the (+)-enantiomer of cis-chlordane and the (−)-enantiomer of trans-chlordane. PMID:21462235

Mechanistic modeling of pesticide exposure: The missing keystone of honey bee toxicology.

PubMed

Sponsler, Douglas B; Johnson, Reed M

2017-04-01

The role of pesticides in recent honey bee losses is controversial, partly because field studies often fail to detect effects predicted by laboratory studies. This dissonance highlights a critical gap in the field of honey bee toxicology: there exists little mechanistic understanding of the patterns and processes of exposure that link honey bees to pesticides in their environment. The authors submit that 2 key processes underlie honey bee pesticide exposure: 1) the acquisition of pesticide by foraging bees, and 2) the in-hive distribution of pesticide returned by foragers. The acquisition of pesticide by foraging bees must be understood as the spatiotemporal intersection between environmental contamination and honey bee foraging activity. This implies that exposure is distributional, not discrete, and that a subset of foragers may acquire harmful doses of pesticide while the mean colony exposure would appear safe. The in-hive distribution of pesticide is a complex process driven principally by food transfer interactions between colony members, and this process differs importantly between pollen and nectar. High priority should be placed on applying the extensive literature on honey bee biology to the development of more rigorously mechanistic models of honey bee pesticide exposure. In combination with mechanistic effects modeling, mechanistic exposure modeling has the potential to integrate the field of honey bee toxicology, advancing both risk assessment and basic research. Environ Toxicol Chem 2017;36:871-881. © 2016 SETAC. © 2016 SETAC.

Passive sampling approaches used for time-integrated environmental monitoring and Risk Assessment in the tropical Río Tapezco catchment in Costa Rica

NASA Astrophysics Data System (ADS)

Weiss, Frederik; Wey, Hannah; Stamm, Christian; Ruepert, Clemens; Zurbrügg, Christian; Eggen, Rik

2017-04-01

Highest pesticide application rates and high surface runoff potentials are found in tropical countries. Global data indicate that among these countries, Costa Rica's agriculture is one of the most pesticide intensive worldwide. After use, pesticides can be transported from the fields into surface water through heavy raining events via wash-off, leaching, surface runoff and erosion processes, or direct as point source due to poor pesticide application practices and deteriorate the water quality and impair aquatic organisms. Even if the risk of pesticide pollution is well documented in Costa Rica, comprehensive information about the diffuse and direct pesticide entry routes, their environmental behavior, and the degree of water pollution is often lacking. Generally, only grab samples are taken and time integrated methods for environmental monitoring are seldom used so far. There is a need for more time integrated data at catchment scale. Current passive sampling techniques are low-costs options that, when combined with advanced analytical screening methods, allow for a broad assessment of pesticide pollution in streams. This will lead to a better systematic understanding of the environmental fate of pesticides and to describe their impacts to non-target organisms in tropical aquatic environments in the short- and long-term. We implemented such an approach in the tropical Río Tapezco catchment in the Zarcero canton, Costa Rica. The area covers 5112 ha, ranges between an altitude of 1100 and 2200 m above sea level and receives an average annual precipitation of 2000 - 2500 mm/yr. The catchment is intensively used for the horticultural production of vegetables, potatoes and herbs and it is specially characterized by its agricultural fields with steep slopes. The area is a hot spot of pesticide use with an average application rate of about 22 kg/ha of arable land and cropping cycle. For time-integrated monitoring, the rivers of the study area were sampled at five points in biweekly intervals between end of July and beginning of October 2015 by using three passive sampling systems (Camcather® with styrene-divinylbenzene reverse phase sulfonated discs, polydimethylsiloxane sheets, and a water level proportional water sampler). Additionally, pressure loggers were installed at all sites for recording water temperature and level continuously and daily precipitation data from one meteorological station (Zarcero Palmira) were available. For the quantification of about 260 substances GC-MS/MS and LC HR-MS was used. In 2015, more than 60 pesticides were detected in the Río Tapezco catchment with biweekly time weighted average concentrations ranging from few ng/L to several µg/L. Furthermore the available European environmental quality standards for several compounds were exceeded and present a potential risk for water organisms.

Scientists Probe Pesticide Dynamics

ERIC Educational Resources Information Center

Chemical and Engineering News, 1974

1974-01-01

Summarizes discussions of a symposium on pesticide environmental dynamics with emphases upon pesticide transport processes, environmental reactions, and partitioning in air, soil, water and living organisms. Indicates that the goal is to attain knowledge enough to predict pesticide behavior and describe pesticide distribution with models and…

Pesticides exposure assessment of kettleman city using the industrial source complex short-term model version 3.

PubMed

Tao, Jing; Barry, Terrell; Segawa, Randy; Neal, Rosemary; Tuli, Atac

2013-01-01

Kettleman City, California, reported a higher than expected number of birth defect cases between 2007 and 2010, raising the concern of community and government agencies. A pesticide exposure evaluation was conducted as part of a complete assessment of community chemical exposure. Nineteen pesticides that potentially cause birth defects were investigated. The Industrial Source Complex Short-Term Model Version 3 (ISCST3) was used to estimate off-site air concentrations associated with pesticide applications within 8 km of the community from late 2006 to 2009. The health screening levels were designed to indicate potential health effects and used for preliminary health evaluations of estimated air concentrations. A tiered approach was conducted. The first tier modeled simple, hypothetical worst-case situations for each of 19 pesticides. The second tier modeled specific applications of the pesticides with estimated concentrations exceeding health screening levels in the first tier. The pesticide use report database of the California Department of Pesticide Regulation provided application information. Weather input data were summarized from the measurements of a local weather station in the California Irrigation Management Information System. The ISCST3 modeling results showed that during the target period, only two application days of one pesticide (methyl isothiocyanate) produced air concentration estimates above the health screening level for developmental effects at the boundary of Kettleman City. These results suggest that the likelihood of birth defects caused by pesticide exposure was low. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Risk assessment of pesticide transport with water erosion: A conceptual model

NASA Astrophysics Data System (ADS)

Yang, Xiaomei; Van Der Zee, Sjoerd E. A. T. M.; Gai, Lingtong; Wesseling, Jan G.; Ritsema, Coen J.; Geissen, Violette

2017-04-01

Pesticides are widely used in agriculture, horticulture, and forestry, and pesticide pollution has become an important issue worldwide. Entraining in runoff and being attached to eroded soil particles, posing a risk to water and soil quality and human health. In order to assess the risk of pesticide during water erosion processes, a simple integrative model of pesticide transport by runoff and erosion was developed. Taking soil hydrological and pesticide behaviour into account, such as water infiltration, erosion, runoff, and pesticide transport and degradation in soil, the conceptual framework was based on the known assumptions such as the convection-dispersion equation and lognormal distributions of soil properties associated with transport, sorption, degradation, and erosion. A sensitivity analysis was conducted and the results indicated that the total amount of pesticide related to soil eroded by water washing increased with slope gradient, rainfall intensity, and water field capacity of the soil. The mass of transported pesticide decreased as the micro-topography of the soil surface became obviously and the time from pesticide sprayed to erosion occurring associated with pesticide degradation negatively influenced the total amount of transported pesticide. The mechanisms involved in pesticide transport, such as runoff, infiltration, soil erosion, and pesticide transport and decay in the topsoil, thus can be well accounted for pesticide risk assessment especially in the region with intensive pesticide use and soil water erosion events.

pH-dependence of pesticide adsorption by wheat-residue-derived black carbon.

PubMed

Yang, Yaning; Chun, Yuan; Sheng, Guangyao; Huang, Minsheng

2004-08-03

The potential of black carbon as an adsorbent for pesticides in soils may be strongly influenced by the properties of the adsorbent and pesticides and by the environmental conditions. This study evaluated the effect of pH on the adsorption of diuron, bromoxynil, and ametryne by a wheat (Triticum aestivum L.) residue derived black carbon (WC) as compared to a commercial activated carbon (AC). The pH drift method indicated that WC had a point of zero charge of 4.2, much lower than that of 7.8 for AC. The density of oxygen-containing surface functional groups, measured by the Boehm titration, on WC was 5.4 times higher than that on AC, resulting in a pesticide adsorption by WC being 30-50% of that by AC, due to the blockage of WC surface by the waters associated with the functional groups. A small decrease (5.5%/unit pH) in diuron adsorption by WC with increase in pH resulted from increased deprotonation of surface functional groups at higher pH values. A much larger decrease (14-21%/unit pH) in bromoxynil adsorption by WC with increase in pH resulted from the deprotonation of both the adsorbate and surface functional groups of the adsorbent. The deprotonation reduced the adsorptive interaction between bromoxynil and the neutral carbon surface and increased the electrical repulsion between the negatively charged WC surface and bromoxynil anions. Deprotonation of ametryne with increase in pH over the low pH range increased its fraction of molecular form and thus adsorption on WC by 15%/unit pH. Further increase in pH resulted in a 20%/unit pH decrease in ametryne adsorption by WC due primarily to the development of a negative charge on the surface of WC. The pH-dependent adsorption of pesticides by black carbon may significantly influence their environmental fate in soils.

An EPA Modeling Dashboard for Ecological Assessment of Pesticides

EPA Science Inventory

The EPA registers pesticides for use in the US and approves imported pesticides under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). Before a pesticide can be registered, the EPA must assess whether the pesticide can be used without eing harmful to humans or pos...

Adjustment of pesticide concentrations for temporal changes in analytical recovery, 1992–2010

USGS Publications Warehouse

Martin, Jeffrey D.; Eberle, Michael

2011-01-01

Recovery is the proportion of a target analyte that is quantified by an analytical method and is a primary indicator of the analytical bias of a measurement. Recovery is measured by analysis of quality-control (QC) water samples that have known amounts of target analytes added ("spiked" QC samples). For pesticides, recovery is the measured amount of pesticide in the spiked QC sample expressed as a percentage of the amount spiked, ideally 100 percent. Temporal changes in recovery have the potential to adversely affect time-trend analysis of pesticide concentrations by introducing trends in apparent environmental concentrations that are caused by trends in performance of the analytical method rather than by trends in pesticide use or other environmental conditions. This report presents data and models related to the recovery of 44 pesticides and 8 pesticide degradates (hereafter referred to as "pesticides") that were selected for a national analysis of time trends in pesticide concentrations in streams. Water samples were analyzed for these pesticides from 1992 through 2010 by gas chromatography/mass spectrometry. Recovery was measured by analysis of pesticide-spiked QC water samples. Models of recovery, based on robust, locally weighted scatterplot smooths (lowess smooths) of matrix spikes, were developed separately for groundwater and stream-water samples. The models of recovery can be used to adjust concentrations of pesticides measured in groundwater or stream-water samples to 100 percent recovery to compensate for temporal changes in the performance (bias) of the analytical method.

In-hive Pesticide Exposome: Assessing risks to migratory honey bees from in-hive pesticide contamination in the Eastern United States

NASA Astrophysics Data System (ADS)

Traynor, Kirsten S.; Pettis, Jeffery S.; Tarpy, David R.; Mullin, Christopher A.; Frazier, James L.; Frazier, Maryann; Vanengelsdorp, Dennis

2016-09-01

This study measured part of the in-hive pesticide exposome by analyzing residues from live in-hive bees, stored pollen, and wax in migratory colonies over time and compared exposure to colony health. We summarized the pesticide burden using three different additive methods: (1) the hazard quotient (HQ), an estimate of pesticide exposure risk, (2) the total number of pesticide residues, and (3) the number of relevant residues. Despite being simplistic, these models attempt to summarize potential risk from multiple contaminations in real-world contexts. Colonies performing pollination services were subject to increased pesticide exposure compared to honey-production and holding yards. We found clear links between an increase in the total number of products in wax and colony mortality. In particular, we found that fungicides with particular modes of action increased disproportionally in wax within colonies that died. The occurrence of queen events, a significant risk factor for colony health and productivity, was positively associated with all three proxies of pesticide exposure. While our exposome summation models do not fully capture the complexities of pesticide exposure, they nonetheless help elucidate their risks to colony health. Implementing and improving such models can help identify potential pesticide risks, permitting preventative actions to improve pollinator health.

In-hive Pesticide Exposome: Assessing risks to migratory honey bees from in-hive pesticide contamination in the Eastern United States

PubMed Central

Traynor, Kirsten S.; Pettis, Jeffery S.; Tarpy, David R.; Mullin, Christopher A.; Frazier, James L.; Frazier, Maryann; vanEngelsdorp, Dennis

2016-01-01

This study measured part of the in-hive pesticide exposome by analyzing residues from live in-hive bees, stored pollen, and wax in migratory colonies over time and compared exposure to colony health. We summarized the pesticide burden using three different additive methods: (1) the hazard quotient (HQ), an estimate of pesticide exposure risk, (2) the total number of pesticide residues, and (3) the number of relevant residues. Despite being simplistic, these models attempt to summarize potential risk from multiple contaminations in real-world contexts. Colonies performing pollination services were subject to increased pesticide exposure compared to honey-production and holding yards. We found clear links between an increase in the total number of products in wax and colony mortality. In particular, we found that fungicides with particular modes of action increased disproportionally in wax within colonies that died. The occurrence of queen events, a significant risk factor for colony health and productivity, was positively associated with all three proxies of pesticide exposure. While our exposome summation models do not fully capture the complexities of pesticide exposure, they nonetheless help elucidate their risks to colony health. Implementing and improving such models can help identify potential pesticide risks, permitting preventative actions to improve pollinator health. PMID:27628343

Model methodology for estimating pesticide concentration extremes based on sparse monitoring data

USGS Publications Warehouse

Vecchia, Aldo V.

2018-03-22

This report describes a new methodology for using sparse (weekly or less frequent observations) and potentially highly censored pesticide monitoring data to simulate daily pesticide concentrations and associated quantities used for acute and chronic exposure assessments, such as the annual maximum daily concentration. The new methodology is based on a statistical model that expresses log-transformed daily pesticide concentration in terms of a seasonal wave, flow-related variability, long-term trend, and serially correlated errors. Methods are described for estimating the model parameters, generating conditional simulations of daily pesticide concentration given sparse (weekly or less frequent) and potentially highly censored observations, and estimating concentration extremes based on the conditional simulations. The model can be applied to datasets with as few as 3 years of record, as few as 30 total observations, and as few as 10 uncensored observations. The model was applied to atrazine, carbaryl, chlorpyrifos, and fipronil data for U.S. Geological Survey pesticide sampling sites with sufficient data for applying the model. A total of 112 sites were analyzed for atrazine, 38 for carbaryl, 34 for chlorpyrifos, and 33 for fipronil. The results are summarized in this report; and, R functions, described in this report and provided in an accompanying model archive, can be used to fit the model parameters and generate conditional simulations of daily concentrations for use in investigations involving pesticide exposure risk and uncertainty.

Probabilistic Modeling for Risk Assessment of California Ground Water Contamination by Pesticides

NASA Astrophysics Data System (ADS)

Clayton, M.; Troiano, J.; Spurlock, F.

2007-12-01

The California Department of Pesticide Regulation (DPR) is responsible for the registration of pesticides in California. DPR's Environmental Monitoring Branch evaluates the potential for pesticide active ingredients to move to ground water under legal agricultural use conditions. Previous evaluations were primarily based on threshold values for specific persistence and mobility properties of pesticides as prescribed in the California Pesticide Contamination Prevention Act of 1985. Two limitations identified with that process were the univariate nature where interactions of the properties were not accounted for, and the inability to accommodate multiple values of a physical-chemical property. We addressed these limitations by developing a probabilistic modeling method based on prediction of potential well water concentrations. A mechanistic pesticide transport model, LEACHM, is used to simulate sorption, degradation and transport of a candidate pesticide through the root zone. A second empirical model component then simulates pesticide degradation and transport through the vadose zone to a receiving ground water aquifer. Finally, degradation during transport in the aquifer to the well screen is included in calculating final potential well concentrations. Using Monte Carlo techniques, numerous LEACHM simulations are conducted using random samples of the organic carbon normalized soil adsorption coefficients (Koc) and soil dissipation half-life values derived from terrestrial field dissipation (TFD) studies. Koc and TFD values are obtained from gamma distributions fitted to pooled data from agricultural-use pesticides detected in California ground water: atrazine, simazine, diuron, bromacil, hexazinone, and norflurazon. The distribution of predicted well water concentrations for these pesticides is in good agreement with concentrations measured in domestic wells in coarse, leaching vulnerable soils of Fresno and Tulure Counties. The leaching potential of a new pesticide is evaluated by substituting it's sorption and persistence data into the model. Because such Koc and TFD data are often sparse, model inputs are typically derived from sampling of a fitted simple triangular distribution. A new product is considered to be a potential ground water contaminant if the 95th percentile of predicted well water concentrations is greater than 0.05 mg/L.

AN INDOOR PESTICIDE AIR AND SURFACE CONCENTRATION MODEL

EPA Science Inventory

A thorough assessment of human exposure to environmental chemicals requires consideration of all processes in the sequence from source to dose. For assessment of exposure to pesticides following their use indoors, data and models are needed to estimate pesticide concentrations...

Aquatic risk assessment of a realistic exposure to pesticides used in bulb crops: a microcosm study.

PubMed

van Wijngaarden, René P A; Cuppen, Jan G M; Arts, Gertie H P; Crum, Steven J H; van den Hoorn, Martin W; van den Brink, Paul J; Brock, Theo C M

2004-06-01

The fungicide fluazinam, the insecticide lambda-cyhalothrin, and the herbicides asulam and metamitron were applied to indoor freshwater microcosms (water volume approximately 0.6 m3). The treatment regime was based on a realistic application scenario in tulip cultivation. Concentrations of each pesticide were equal to 0%, 0.2%, 0.5%, 2%, and 5% spray drift emission of label-recommended rates. Contribution of compounds to the toxicity of the pesticide package was established by expressing their concentrations as fractions of toxic units. The fate of the compounds in the water, and responses of phytoplankton, zooplankton, periphyton, macroinvertebrates, macrophytes, decomposition, and water quality were followed for 13 weeks. The half-lives of lambda-cyhalothrin, metamitron, and fluazinam were 1 to 2 d; that of asulam was >30 d. No consistent effects could be demonstrated for the 0.2% treatment regime that was therefore considered the no-observed-effect concentration community (NOEC). The macroinvertebrate populations of Gammarus pulex, Asellus aquaticus, and Proasellus meridianus were the most sensitive end points, followed by species of copepods and cladocerans. Responses mainly were due to lambda-cyhalothrin. The 0.5% treatment regime resulted in short-term effects. Pronounced effects were observed at the 2% and 5% treatment levels. At the end of the experiment, the macrophyte biomass that consisted of Elodea nuttallii, showed a decline at the two highest treatment levels, asulam being the causal factor (NOEC: 0.5% treatment level). Primary production was reduced at the 5% treatment level only. In our experiment, the first-tier risk assessment procedure for individual compounds was adequate for protecting sensitive populations exposed to realistic combinations of pesticides. Spray drift reduction measures seem to be efficient in protecting aquatic ecosystems in agricultural areas.

Occurrence of transformation products in the environment

USGS Publications Warehouse

Kolpin, Dana W.; Battaglin, William A.; Conn, Kathleen E.; Furlong, Edward T.; Glassmeyer, Susan T.; Kalkhoff, Stephen J.; Meyer, Michael T.; Schnoebelen, Douglas J.; Boxall, Alistair B.A.

2009-01-01

Historically, most environmental occurrence research has focused on the parent compounds of organic contaminants. Research, however, has documented that the environmental transport of chemicals, such as pesticides and emerging contaminants, are substantially underestimated if transformation products are not considered. Although most examples described herein were drawn from research conducted by the U.S. Geological Survey, such results are generally reflective of those found in other parts of the world. Results from a study of 51 streams in the Midwestern United States found that transformation products were seven of the ten most frequently detected pesticide compounds in late spring runoff (after application of pre-emergent herbicides), and nine of the ten most frequently detected compounds in fall season runoff (during and after harvest). In fact, 70% of the total herbicide concentration in water from the Mississippi River Basin was from transformation products. Results from a study of 86 municipal wells in Iowa found the frequency of detection increased from 17%, when pesticide parent compounds were considered, to 53%, when both parents and transformation products were considered. Transformation products were 12 of the 15 most frequently detected compounds for this groundwater study. Although studies on transformation products of synthetic organic compounds other than pesticides are not as common, wastewater treatment plant discharges have repeatedly been shown to contribute such transformation products to streams. In addition, select detergent transformation products have been commonly found in solid waste in the 1000's mg/kg. These findings and many others document that transformation products must be considered to fully assess the potential environmental occurrence of chemical contaminants and their transport and fate in various compartments of the hydrologic system. ?? 2008 Springer-Verlag Berlin Heidelberg.

Environmental Metabolic Footprinting (EMF) vs. half-life: a new and integrative proxy for the discrimination between control and pesticides exposed sediments in order to further characterise pesticides' environmental impact.

PubMed

Salvia, Marie-Virginie; Ben Jrad, Amani; Raviglione, Delphine; Zhou, Yuxiang; Bertrand, Cédric

2017-06-28

Pesticides are regularly used for a variety of applications and are disseminated throughout the environment. These substances may have significant negative impacts. To date, the half-life, t 1/2 , was often used to study the fate of pesticides in environmental matrices (water, soil, sediment). However, this value gives limited information. First, it does not evaluate the formation of by-products, resulting in the need for additional experiments to be performed to evaluate biodegradation and biotransformation products. T 1/2 also fails to consider the chemical's impact on biodiversity. Resilience time, a new and integrative proxy, was recently proposed as an alternative to t 1/2 , with the potential to evaluate all the post-application effects of the chemical on the environment. The 'Environmental Metabolic Footprinting' (EMF) approach, giving an idea of the resilience time, was used to evaluate the impact of botanicals on soil. The goal is to optimise the EMF to study the impact of a microbial insecticide, the Bacillus thuringiensis israelensis (Bti), on sediment. The difficulty of this work lies in the commercial solution of Bti that is really complex, and this complexity yields chromatograms that are extremely difficult to interpret; t 1/2 cannot be used. No methodologies currently exist to monitor the impact of these compounds on the environment. We will test the EMF to determine if it is sensitive enough to tolerate such complex mixtures. A pure chemical insecticide, the α-cypermethrin, will be also studied. The article shows that the EMF is able to distinguish meta-metabolome differences between control and exposed (with Bti) sediments.

Structural equation modeling of the relationships between pesticide poisoning, depressive symptoms and safety behaviors among Colorado farm residents.

PubMed

Beseler, Cheryl Lynn; Stallones, Lorann

2006-01-01

To use structural equation modeling (SEM) to test the theory that a past pesticide poisoning may act as a mediator in the relationship between depression and safety practices. Depression has been associated with pesticide poisoning and was more strongly associated with safety behaviors than workload, social support or health status of farm residents in a previously published report. A cross-sectional survey of farmers and their spouses was conducted in eight counties in northeastern Colorado. Depressive symptoms were assessed using the Center for Epidemiologic Studies-Depression (CES-D) scale. Exploratory and confirmatory factor analyses were used to identify symptoms most correlated with risk factors for depression and safety practices. SEM was used to examine theoretical causal models of the relationship between depression and poor health, financial difficulties, a history of pesticide poisoning, and safety practices. Exploratory factor analysis identified three factors in the CES-D scale. The SEM showed that poor health, financial difficulties and a history of pesticide poisoning significantly explained the depressive symptoms. Models with an excellent fit for the safety behaviors resulted when modeling the probability that the pesticide poisoning preceded depression, but no fit was possible when reversing the direction and modeling depression preceding pesticide poisoning. Specific depressive symptoms appeared to be significantly associated with primarily animal handling and farm machinery. The order of events, based on SEM results, was a pesticide poisoning preceding depressed mood in relation to safety behaviors.

Sensitivity analysis for simulating pesticide impacts on honey bee colonies

EPA Science Inventory

Background/Question/Methods Regulatory agencies assess risks to honey bees from pesticides through a tiered process that includes predictive modeling with empirical toxicity and chemical data of pesticides as a line of evidence. We evaluate the Varroapop colony model, proposed by...

MODELING EXPOSURES TO PESTICIDES APPROACHES AND MODELING NEEDS

EPA Science Inventory

Estimation of exposures of children to pesticides requires careful consideration of sources and concentrations of pesticides that may be present in different environmental media and in foods and beverages consumed by children, as well as the different routes and pathways of exp...

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

PubMed

Li, Chen; Nagasaki, Masao; Ueno, Kazuko; Miyano, Satoru

2009-04-27

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. 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 1986. Our simulation results suggest that: Rule I that cannot be applied with qualitative based model checking, is more reasonable than Rule II owing to the high coverage of predicted fate patterns (except for the genotype of lin-15ko; lin-12ko double mutants). More insights are also suggested. The quantitative simulation-based model checking approach is a useful means to provide us valuable biological insights and better understandings of biological systems and observation data that may be hard to capture with the qualitative one.

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

EPA Science Inventory

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...

Estimation of pyrethroid pesticide intake using regression modeling of food groups based on composite dietary samples

EPA Science Inventory

Population-based estimates of pesticide intake are needed to characterize exposure for particular demographic groups based on their dietary behaviors. Regression modeling performed on measurements of selected pesticides in composited duplicate diet samples allowed (1) estimation ...

Estimation of pyrethroid pesticide intake using regression modeling of food groups based on composite dietary samples..

EPA Science Inventory

Population-based estimates of pesticide intake are needed to characterize exposure for particular demographic groups based on their dietary behaviors. Regression modeling performed on measurements of selected pesticides in composited duplicate diet samples allowed (1) estimation ...

Estimation of pyrethroid pesticide intake using regression modeling of food groups based on composite dietary samples.

EPA Science Inventory

Population-based estimates of pesticide intake are needed to characterize exposure for particular demographic groups based on their dietary behaviors. Regression modeling performed on measurements of selected pesticides in composited duplicate diet samples allowed (1) estimation ...

Assessing human health risks from pesticide use in conventional and innovative cropping systems with the BROWSE model.

PubMed

Lammoglia, Sabine-Karen; Kennedy, Marc C; Barriuso, Enrique; Alletto, Lionel; Justes, Eric; Munier-Jolain, Nicolas; Mamy, Laure

2017-08-01

Reducing the risks and impacts of pesticide use on human health and on the environment is one of the objectives of the European Commission Directive 2009/128/EC in the quest for a sustainable use of pesticides. This Directive, developed through European national plans such as Ecophyto plan in France, promotes the introduction of innovative cropping systems relying, for example, on integrated pest management. Risk assessment for human health of the overall pesticide use in these innovative systems is required before the introduction of those systems to avoid that an innovation becomes a new problem. The objectives of this work were to assess and to compare (1) the human exposure to pesticides used in conventional and innovative cropping systems designed to reduce pesticide needs, and (2) the corresponding risks for human health. Humans (operator and residents) exposure to pesticides and risks for human health were assessed for each pesticide with the BROWSE model. Then, a method was proposed to represent the overall risk due to all pesticides used in one system. This study considers 3 conventional and 9 associated innovative cropping systems, and 116 plant protection products containing 89 different active substances (i.e. pesticides). The modelling results obtained with BROWSE showed that innovative cropping systems such as low input or no herbicide systems would reduce the risk for human health in comparison to the corresponding conventional cropping systems. On the contrary, BROWSE showed that conservation tillage system would lead to unacceptable risks in the conditions of our study, because of a high number of pesticide applications, and especially of some herbicides. For residents, the dermal absorption was the main exposure route while ingestion was found to be negligible. For operators, inhalation was also a predominant route of exposure. In general, human exposure to pesticides and human health risks were found to be correlated to the treatment frequency index TFI (number of registered doses of pesticides used per hectare for one copping season), confirming the relationship between the reduction of pesticide use and the reduction of risks. Assessment with the BROWSE model helped to identify cropping systems with decreased risks from pesticides for human health and to propose some improvements to the cropping systems by identifying the pesticides that led to unacceptable risks. Copyright © 2017 Elsevier Ltd. All rights reserved.

Adjustment of Pesticide Concentrations for Temporal Changes in Analytical Recovery, 1992-2006

USGS Publications Warehouse

Martin, Jeffrey D.; Stone, Wesley W.; Wydoski, Duane S.; Sandstrom, Mark W.

2009-01-01

Recovery is the proportion of a target analyte that is quantified by an analytical method and is a primary indicator of the analytical bias of a measurement. Recovery is measured by analysis of quality-control (QC) water samples that have known amounts of target analytes added ('spiked' QC samples). For pesticides, recovery is the measured amount of pesticide in the spiked QC sample expressed as percentage of the amount spiked, ideally 100 percent. Temporal changes in recovery have the potential to adversely affect time-trend analysis of pesticide concentrations by introducing trends in environmental concentrations that are caused by trends in performance of the analytical method rather than by trends in pesticide use or other environmental conditions. This report examines temporal changes in the recovery of 44 pesticides and 8 pesticide degradates (hereafter referred to as 'pesticides') that were selected for a national analysis of time trends in pesticide concentrations in streams. Water samples were analyzed for these pesticides from 1992 to 2006 by gas chromatography/mass spectrometry. Recovery was measured by analysis of pesticide-spiked QC water samples. Temporal changes in pesticide recovery were investigated by calculating robust, locally weighted scatterplot smooths (lowess smooths) for the time series of pesticide recoveries in 5,132 laboratory reagent spikes; 1,234 stream-water matrix spikes; and 863 groundwater matrix spikes. A 10-percent smoothing window was selected to show broad, 6- to 12-month time scale changes in recovery for most of the 52 pesticides. Temporal patterns in recovery were similar (in phase) for laboratory reagent spikes and for matrix spikes for most pesticides. In-phase temporal changes among spike types support the hypothesis that temporal change in method performance is the primary cause of temporal change in recovery. Although temporal patterns of recovery were in phase for most pesticides, recovery in matrix spikes was greater than recovery in reagent spikes for nearly every pesticide. Models of recovery based on matrix spikes are deemed more appropriate for adjusting concentrations of pesticides measured in groundwater and stream-water samples than models based on laboratory reagent spikes because (1) matrix spikes are expected to more closely match the matrix of environmental water samples than are reagent spikes and (2) method performance is often matrix dependent, as was shown by higher recovery in matrix spikes for most of the pesticides. Models of recovery, based on lowess smooths of matrix spikes, were developed separately for groundwater and stream-water samples. The models of recovery can be used to adjust concentrations of pesticides measured in groundwater or stream-water samples to 100 percent recovery to compensate for temporal changes in the performance (bias) of the analytical method.

ESTIMATION OF GROUNDWATER POLLUTION POTENTIAL BY PESTICIDES IN MID-ATLANTIC COASTAL PLAIN WATERSHEDS

EPA Science Inventory

A simple GIS-based transport model to estimate the potential for groundwater pollution by pesticides has been developed within the ArcView GIS environment. The pesticide leaching analytical model, which is based on one-dimensional advective-dispersive-reactive (ADR) transport, ha...

Conducting field studies for testing pesticide leaching models

USGS Publications Warehouse

Smith, Charles N.; Parrish, Rudolph S.; Brown, David S.

1990-01-01

A variety of predictive models are being applied to evaluate the transport and transformation of pesticides in the environment. These include well known models such as the Pesticide Root Zone Model (PRZM), the Risk of Unsaturated-Saturated Transport and Transformation Interactions for Chemical Concentrations Model (RUSTIC) and the Groundwater Loading Effects of Agricultural Management Systems Model (GLEAMS). The potentially large impacts of using these models as tools for developing pesticide management strategies and regulatory decisions necessitates development of sound model validation protocols. This paper offers guidance on many of the theoretical and practical problems encountered in the design and implementation of field-scale model validation studies. Recommendations are provided for site selection and characterization, test compound selection, data needs, measurement techniques, statistical design considerations and sampling techniques. A strategy is provided for quantitatively testing models using field measurements.

TerrPlant Version 1.2.2 User's Guide for Pesticide Exposure to Terrestrial Plants

EPA Pesticide Factsheets

Tier 1 model for screening-level assessments of pesticides. TerrPlant provides screening-level estimates of exposure to terrestrial plants from single pesticide applications. It does not consider exposures to plants from multiple pesticide applications.

Evaluation of Three Models for Simulating Pesticide Runoff from Irrigated Agricultural Fields.

PubMed

Zhang, Xuyang; Goh, Kean S

2015-11-01

Three models were evaluated for their accuracy in simulating pesticide runoff at the edge of agricultural fields: Pesticide Root Zone Model (PRZM), Root Zone Water Quality Model (RZWQM), and OpusCZ. Modeling results on runoff volume, sediment erosion, and pesticide loss were compared with measurements taken from field studies. Models were also compared on their theoretical foundations and ease of use. For runoff events generated by sprinkler irrigation and rainfall, all models performed equally well with small errors in simulating water, sediment, and pesticide runoff. The mean absolute percentage errors (MAPEs) were between 3 and 161%. For flood irrigation, OpusCZ simulated runoff and pesticide mass with the highest accuracy, followed by RZWQM and PRZM, likely owning to its unique hydrological algorithm for runoff simulations during flood irrigation. Simulation results from cold model runs by OpusCZ and RZWQM using measured values for model inputs matched closely to the observed values. The MAPE ranged from 28 to 384 and 42 to 168% for OpusCZ and RZWQM, respectively. These satisfactory model outputs showed the models' abilities in mimicking reality. Theoretical evaluations indicated that OpusCZ and RZWQM use mechanistic approaches for hydrology simulation, output data on a subdaily time-step, and were able to simulate management practices and subsurface flow via tile drainage. In contrast, PRZM operates at daily time-step and simulates surface runoff using the USDA Soil Conservation Service's curve number method. Among the three models, OpusCZ and RZWQM were suitable for simulating pesticide runoff in semiarid areas where agriculture is heavily dependent on irrigation. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

SPRAYTRAN 1.0 User’s Guide: A GIS-Based Atmospheric Spray Droplet Dispersion Modeling System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allwine, K Jerry; Rutz, Frederick C.; Droppo, James G.

SPRAY TRANsport (SPRAYTRAN) is a comprehensive dispersion modeling system that is used to simulate the offsite drift of pesticides from spray applications. SPRAYTRAN functions as a console application within Environmental System Research Institute’s ArcMap Geographic Information System (Version 9.x) and integrates the widely-used, U.S. Environmental Protection Agency (EPA)-approved CALifornia PUFF (CALPUFF) dispersion model and model components to simulate longer-range transport and diffusion in variable terrain and spatially/temporally varying meteorological (e.g., wind) fields. Area sources, which are used to define spray blocks in SPRAYTRAN, are initialized using output files generated from a separate aerial-spray-application model called AGDISP (AGricultural DISPersal). The AGDISPmore » model is used for estimating the amount of pesticide deposited to the spray block based on spraying characteristics (e.g., pesticide type, spray nozzles, and aircraft type) and then simulating the near-field (less than 300-m) drift from a single pesticide application. The fraction of pesticide remaining airborne from the AGDISP near-field simulation is then used by SPRAYTRAN for simulating longer-range (greater than 300 m) drift and deposition of the pesticide.« less

Dynamical crossover in a stochastic model of cell fate decision

NASA Astrophysics Data System (ADS)

Yamaguchi, Hiroki; Kawaguchi, Kyogo; Sagawa, Takahiro

2017-07-01

We study the asymptotic behaviors of stochastic cell fate decision between proliferation and differentiation. We propose a model of a self-replicating Langevin system, where cells choose their fate (i.e., proliferation or differentiation) depending on local cell density. Based on this model, we propose a scenario for multicellular organisms to maintain the density of cells (i.e., homeostasis) through finite-ranged cell-cell interactions. Furthermore, we numerically show that the distribution of the number of descendant cells changes over time, thus unifying the previously proposed two models regarding homeostasis: the critical birth death process and the voter model. Our results provide a general platform for the study of stochastic cell fate decision in terms of nonequilibrium statistical mechanics.

seawaveQ: an R package providing a model and utilities for analyzing trends in chemical concentrations in streams with a seasonal wave (seawave) and adjustment for streamflow (Q) and other ancillary variables

USGS Publications Warehouse

Ryberg, Karen R.; Vecchia, Aldo V.

2013-01-01

The seawaveQ R package fits a parametric regression model (seawaveQ) to pesticide concentration data from streamwater samples to assess variability and trends. The model incorporates the strong seasonality and high degree of censoring common in pesticide data and users can incorporate numerous ancillary variables, such as streamflow anomalies. The model is fitted to pesticide data using maximum likelihood methods for censored data and is robust in terms of pesticide, stream location, and degree of censoring of the concentration data. This R package standardizes this methodology for trend analysis, documents the code, and provides help and tutorial information, as well as providing additional utility functions for plotting pesticide and other chemical concentration data.

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

PubMed

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.

Distribution and fate of HCH isomers and DDT metabolites in a tropical environment-case study Cameron Highlands-Malaysia.

PubMed

Saadati, Naghmeh; Abdullah, Md Pauzi; Zakaria, Zuriati; Rezayi, Majid; Hosseinizare, Nader

2012-11-07

The serious impact effects of persistent organic pollutants such as organochlorine pesticides, especially dichlorodiphenyltrichloroethane family (DDTs) and hexachlorocyclohexane isomers (HCHs) have been causing widespread concern, despite effective control on their manufacturing, agricultural and vector practices. In that, in addition to the previous global limitations on DDTs usage, α-HCH, β-HCH and lindane have also became an on-going topic of global relevance based on the latest Stockholm Convention list on 10th of May 2009. Concentrations of dichlorodiphenyltrichloroethane family (DDTs) and hexachlorocyclohexane isomers (HCHs) were determined by GC-ECD in Cameron Highlands, the main vegetables and flowers farming area in Malaysia as an agricultural tropical environment. A total of 112 surface water and sediment samples at eight points were collected along the main rivers in the area namely Telom and Bertam in the dry and wet seasons of 2011. Total concentration of HCH isomers ranged from not detected to 25.03 ng/L in the water (mean of 5.55 ±6.0 ng/L), while, it ranged from 0.002 to 59.17 ng/g (mean of 8.06±9.39 ng/g) in the sediment. Total concentration of DDT and its metabolites in the water samples varied from not detected to 8.0 ng/L (mean of 0.90±1.66 ng/g), whereas, it was in the range of 0.025 to 23.24 ng/g (mean of 2.55±4.0 ng/g) in the surface sediment samples. The ratio of HCHs and DDTs composition indicated an obvious historical usage and new inputs of these pesticides. Among alpha, beta, gamma and delta isomers of HCH, gamma was the most dominant component in the sediment and water as well. Some seasonal variations in the level of selected pesticides were noted. The results illustrate distribution, behaviour and fate of HCHs, and DDTs have closely connected with topological and meteorological properties of the area beyond their chemical characterizations. The features of environmental circumstances exceed one or more of these characters in importance than the other. Although the results show that the situation is better than 1998, the impact of persistent agrochemicals such as lindane and 4,4'DDE are revealed in a key tropical area of Malaysia.

Distribution and fate of HCH isomers and DDT metabolites in a tropical environment–case study Cameron Highlands–Malaysia

PubMed Central

2012-01-01

Background The serious impact effects of persistent organic pollutants such as organochlorine pesticides, especially dichlorodiphenyltrichloroethane family (DDTs) and hexachlorocyclohexane isomers (HCHs) have been causing widespread concern, despite effective control on their manufacturing, agricultural and vector practices. In that, in addition to the previous global limitations on DDTs usage, α-HCH, β-HCH and lindane have also became an on-going topic of global relevance based on the latest Stockholm Convention list on 10th of May 2009. Concentrations of dichlorodiphenyltrichloroethane family (DDTs) and hexachlorocyclohexane isomers (HCHs) were determined by GC-ECD in Cameron Highlands, the main vegetables and flowers farming area in Malaysia as an agricultural tropical environment. A total of 112 surface water and sediment samples at eight points were collected along the main rivers in the area namely Telom and Bertam in the dry and wet seasons of 2011. Results Total concentration of HCH isomers ranged from not detected to 25.03 ng/L in the water (mean of 5.55 ±6.0 ng/L), while, it ranged from 0.002 to 59.17 ng/g (mean of 8.06±9.39 ng/g) in the sediment. Total concentration of DDT and its metabolites in the water samples varied from not detected to 8.0 ng/L (mean of 0.90±1.66 ng/g), whereas, it was in the range of 0.025 to 23.24 ng/g (mean of 2.55±4.0 ng/g) in the surface sediment samples. The ratio of HCHs and DDTs composition indicated an obvious historical usage and new inputs of these pesticides. Among alpha, beta, gamma and delta isomers of HCH, gamma was the most dominant component in the sediment and water as well. Some seasonal variations in the level of selected pesticides were noted. Conclusions The results illustrate distribution, behaviour and fate of HCHs, and DDTs have closely connected with topological and meteorological properties of the area beyond their chemical characterizations. The features of environmental circumstances exceed one or more of these characters in importance than the other. Although the results show that the situation is better than 1998, the impact of persistent agrochemicals such as lindane and 4,4′DDE are revealed in a key tropical area of Malaysia. PMID:23130650

MEASURED CONCENTRATIONS OF HERBICIDES AND MODEL PREDICTIONS OF ATRAZINE FATE IN THE PATUXENT RIVER ESTUARY

EPA Science Inventory

McConnell, Laura L., Jennifer A. Harman-Fetcho and James D. Hagy, III. 2004. Measured Concentrations of Herbicides and Model Predictions of Atrazine Fate in the Patuxent River Estuary. J. Environ. Qual. 33(2):594-604. (ERL,GB X1051).

The environmental fate of herbicides i...

Polychlorinated Biphenyls in a Temperate Alpine Glacier: 2. Model Results of Chemical Fate Processes.

PubMed

Steinlin, Christine; Bogdal, Christian; Pavlova, Pavlina A; Schwikowski, Margit; Lüthi, Martin P; Scheringer, Martin; Schmid, Peter; Hungerbühler, Konrad

2015-12-15

We present results from a chemical fate model quantifying incorporation of polychlorinated biphenyls (PCBs) into the Silvretta glacier, a temperate Alpine glacier located in Switzerland. Temperate glaciers, in contrast to cold glaciers, are glaciers where melt processes are prevalent. Incorporation of PCBs into cold glaciers has been quantified in previous studies. However, the fate of PCBs in temperate glaciers has never been investigated. In the model, we include melt processes, inducing elution of water-soluble substances and, conversely, enrichment of particles and particle-bound chemicals. The model is validated by comparing modeled and measured PCB concentrations in an ice core collected in the Silvretta accumulation area. We quantify PCB incorporation between 1900 and 2010, and discuss the fate of six PCB congeners. PCB concentrations in the ice core peak in the period of high PCB emissions, as well as in years with strong melt. While for lower-chlorinated PCB congeners revolatilization is important, for higher-chlorinated congeners, the main processes are storage in glacier ice and removal by particle runoff. This study gives insight into PCB fate and dynamics and reveals the effect of snow accumulation and melt processes on the fate of semivolatile organic chemicals in a temperate Alpine glacier.

An adaptive, comprehensive monitoring strategy for chemicals of emerging concern (CECs) in California's Aquatic Ecosystems.

PubMed

Maruya, Keith A; Schlenk, Daniel; Anderson, Paul D; Denslow, Nancy D; Drewes, Jörg E; Olivieri, Adam W; Scott, Geoffrey I; Snyder, Shane A

2014-01-01

A scientific advisory panel was convened by the State of California to recommend monitoring for chemicals of emerging concern (CECs) in aquatic systems that receive discharge of municipal wastewater treatment plant (WWTP) effluent and stormwater runoff. The panel developed a risk-based screening framework that considered environmental sources and fate of CECs observed in receiving waters across the State. Using existing occurrence and risk threshold data in water, sediment, and biological tissue, the panel applied the framework to identify a priority list of CECs for initial monitoring in three representative receiving water scenarios. The initial screening list of 16 CECs identified by the panel included consumer and commercial chemicals, flame retardants, pesticides, pharmaceuticals and personal care products, and natural hormones. The panel designed an iterative, phased strategy with interpretive guidelines that direct and update management actions commensurate with potential risk identified using the risk-based framework and monitoring data. Because of the ever-changing nature of chemical use, technology, and management practices, the panel offered recommendations to improve CEC monitoring, including development of bioanalytical screening methods whose responses integrate exposure to complex mixtures and that can be linked to higher-order effects; development or refinement of models that predict the input, fate, and effects of future chemicals; and filling of key data gaps on CEC occurrence and toxicity. Finally, the panel stressed the need for adaptive management, allowing for future review of, and if warranted, modifications to the strategy to incorporate the latest science available to the water resources community. © 2013 SETAC.

Computational fluid dynamics modeling of transport and deposition of pesticides in an aircraft cabin

PubMed Central

Isukapalli, Sastry S.; Mazumdar, Sagnik; George, Pradeep; Wei, Binnian; Jones, Byron; Weisel, Clifford P.

2015-01-01

Spraying of pesticides in aircraft cabins is required by some countries as part of a disinsection process to kill insects that pose a public health threat. However, public health concerns remain regarding exposures of cabin crew and passengers to pesticides in aircraft cabins. While large scale field measurements of pesticide residues and air concentrations in aircraft cabins scenarios are expensive and time consuming, Computational Fluid Dynamics (CFD) models provide an effective alternative for characterizing concentration distributions and exposures. This study involved CFD modeling of a twin-aisle 11 row cabin mockup with heated manikins, mimicking a part of a fully occupied Boeing 767 cabin. The model was applied to study the flow and deposition of pesticides under representative scenarios with different spraying patterns (sideways and overhead) and cabin air exchange rates (low and high). Corresponding spraying experiments were conducted in the cabin mockup, and pesticide deposition samples were collected at the manikin’s lap and seat top for a limited set of five seats. The CFD model performed well for scenarios corresponding to high air exchange rates, captured the concentration profiles for middle seats under low air exchange rates, and underestimated the concentrations at window seats under low air exchange rates. Additionally, both the CFD and experimental measurements showed no major variation in deposition characteristics between sideways and overhead spraying. The CFD model can estimate concentration fields and deposition profiles at very high resolutions, which can be used for characterizing the overall variability in air concentrations and surface loadings. Additionally, these model results can also provide a realistic range of surface and air concentrations of pesticides in the cabin that can be used to estimate potential exposures of cabin crew and passengers to these pesticides. PMID:25642134

Pesticide exposure and end-stage renal disease risk among wives of pesticide applicators in the Agricultural Health Study.

PubMed

Lebov, Jill F; Engel, Lawrence S; Richardson, David; Hogan, Susan L; Sandler, Dale P; Hoppin, Jane A

2015-11-01

Pesticide exposure has been found to cause renal damage and dysfunction in experimental studies, but epidemiological research on the renal effects of chronic low-level pesticide exposure is limited. We investigated the relationships between end-stage renal disease (ESRD) among wives of licensed pesticide applicators (N=31,142) in the Agricultural Health Study (AHS) and (1) personal pesticide use, (2) exposure to the husband's pesticide use, and (3) other pesticide-associated farming and household activities. AHS participants reported pesticide exposure via self-administered questionnaires at enrollment (1993-1997). ESRD cases were identified via linkage to the United States Renal Data System. Associations between ESRD and pesticide exposures were estimated with Cox proportional hazard regression models controlling for age at enrollment. Models of associations with farming and household factors were additionally adjusted for personal use of pesticides. We identified 98 ESRD cases diagnosed between enrollment and 31 December 2011. Although women who ever applied pesticides (56% of cohort) were less likely than those who did not apply to develop ESRD (Hazard Ratio (HR): 0.42; 95% CI: 0.28, 0.64), among women who did apply pesticides, the rate of ESRD was significantly elevated among those who reported the highest (vs. lowest) cumulative general pesticide use (HR: 4.22; 95% CI: 1.26, 14.20). Among wives who never applied pesticides, ESRD was associated with husbands' ever use of paraquat (HR=1.99; 95% CI: 1.14, 3.47) and butylate (HR=1.71; 95% CI: 1.00, 2.95), with a positive exposure-response pattern for husband's cumulative use of these pesticides. ESRD may be associated with direct and/or indirect exposure to pesticides among farm women. Future studies should evaluate indirect exposure risk among other rural populations. Published by Elsevier Inc.

CHILDREN'S RESIDENTIAL EXPOSURE TO CHLORPYRIFOS: APPLICATION OF CPPAES FIELD MEASUREMENTS OF CHLORPYRIFOS AND TCPY WITHIN MENTOR/SHEDS PESTICIDES MODEL

EPA Science Inventory

The comprehensive individual field-measurements on non-dietary exposure collected in the Children's-Post-Pesticide-Application-Exposure-Study (CPPAES) were used within MENTOR/SHEDS-Pesticides, a physically based stochastic human exposure and dose model. In this application, howev...

Comparison of Four Probabilistic Models (CARES, Calendex, ConsEspo, SHEDS) to Estimate Aggregate Residential Exposures to Pesticides

EPA Science Inventory

Two deterministic models (US EPA’s Office of Pesticide Programs Residential Standard Operating Procedures (OPP Residential SOPs) and Draft Protocol for Measuring Children’s Non-Occupational Exposure to Pesticides by all Relevant Pathways (Draft Protocol)) and four probabilistic mo...

MATHEMATICAL MODELING OF PESTICIDES IN THE ENVIRONMENT: CURRENT AND FUTURE DEVELOPMENTS

EPA Science Inventory

Transport models, total ecosystem models with aggregated linear approximations, evaluative models, hierarchical models, and influence analysis methods are mathematical techniques that are particularly applicable to the problems encountered when characterizing pesticide chemicals ...

Pesticides are Associated with Allergic and Non-Allergic Wheeze among Male Farmers.

PubMed

Hoppin, Jane A; Umbach, David M; Long, Stuart; London, Stephanie J; Henneberger, Paul K; Blair, Aaron; Alavanja, Michael; Freeman, Laura E Beane; Sandler, Dale P

2017-04-01

Growing evidence suggests that pesticide use may contribute to respiratory symptoms. We evaluated the association of currently used pesticides with allergic and non-allergic wheeze among male farmers. Using the 2005-2010 interview data of the Agricultural Health Study, a prospective study of farmers in North Carolina and Iowa, we evaluated the association between allergic and non-allergic wheeze and self-reported use of 78 specific pesticides, reported by ≥ 1% of the 22,134 men interviewed. We used polytomous regression models adjusted for age, BMI, state, smoking, and current asthma, as well as for days applying pesticides and days driving diesel tractors. We defined allergic wheeze as reporting both wheeze and doctor-diagnosed hay fever ( n = 1,310, 6%) and non-allergic wheeze as reporting wheeze but not hay fever ( n = 3,939, 18%); men without wheeze were the referent. In models evaluating current use of specific pesticides, 19 pesticides were significantly associated ( p < 0.05) with allergic wheeze (18 positive, 1 negative) and 21 pesticides with non-allergic wheeze (19 positive, 2 negative); 11 pesticides were associated with both. Seven pesticides (herbicides: 2,4-D and simazine; insecticides: carbaryl, dimethoate, disulfoton, and zeta-cypermethrin; and fungicide pyraclostrobin) had significantly different associations for allergic and non-allergic wheeze. In exposure-response models with up to five exposure categories, we saw evidence of an exposure-response relationship for several pesticides including the commonly used herbicides 2,4-D and glyphosate, the insecticides permethrin and carbaryl, and the rodenticide warfarin. These results for farmers implicate several pesticides that are commonly used in agricultural and residential settings with adverse respiratory effects.

Pesticide transport with runoff from turf: observations compared with TurfPQ model simulations.

PubMed

Kramer, Kirsten E; Rice, Pamela J; Horgan, Brian P; Rittenhouse, Jennifer L; King, Kevin W

2009-01-01

Pesticides applied to turf grass have been detected in surface waters raising concerns of their effect on water quality and interest in their source, hydrological transport and use of models to predict transport. TurfPQ, a pesticide runoff model for turf grass, predicts pesticide transport but has not been rigorously validated for larger storms. The objective of this study was to determine TurfPQ's ability to accurately predict the transport of pesticides with runoff following more intense precipitation. The study was conducted with creeping bentgrass [Agrostis palustris Huds.] turf managed as a golf course fairway. A pesticide mixture containing dicamba, 2,4-D, MCPP, flutolanil, and chlorpyrifos was applied to six adjacent 24.4 by 6.1 m plots. Controlled rainfall simulations were conducted using a rainfall simulator designed to deliver water droplets similar to natural rain. Runoff flow rates and volume were measured and water samples were collected for analysis of pesticide concentrations. Six simulations yielded 13 events with which to test TurfPQ. Measured mean percentage of applied pesticide recovered in the runoff for dicamba, 2,4-D, MCPP, flutolanil, and chlorpyrifos was 24.6, 20.7, 14.9, 5.9, and 0.8%, respectively. The predicted mean values produced by TurfPQ were 13.7, 15.6, 15.5, 2.5, and 0.2%, respectively. The model produced correlations of r=0.56 and 0.64 for curve number hydrology and measured hydrology, respectively. Comparisons of the model estimates with our field observations indicate that TurfPQ under predicted pesticide runoff during 69.5+/-11.4 mm, 1.9+/-0.2 h, simulated storms.

Modeling pesticide loadings from the San Joaquin watershed into the Sacramento-San Joaquin Delta using SWAT

NASA Astrophysics Data System (ADS)

Chen, H.; Zhang, M.

2016-12-01

The Sacramento-San Joaquin Delta is an ecologically rich, hydrologically complex area that serves as the hub of California's water supply. However, pesticides have been routinely detected in the Delta waterways, with concentrations exceeding the benchmark for the protection of aquatic life. Pesticide loadings into the Delta are partially attributed to the San Joaquin watershed, a highly productive agricultural watershed located upstream. Therefore, this study aims to simulate pesticide loadings to the Delta by applying the Soil and Water Assessment Tool (SWAT) model to the San Joaquin watershed, under the support of the USDA-ARS Delta Area-Wide Pest Management Program. Pesticide use patterns in the San Joaquin watershed were characterized by combining the California Pesticide Use Reporting (PUR) database and GIS analysis. Sensitivity/uncertainty analyses and multi-site calibration were performed in the simulation of stream flow, sediment, and pesticide loads along the San Joaquin River. Model performance was evaluated using a combination of graphic and quantitative measures. Preliminary results indicated that stream flow was satisfactorily simulated along the San Joaquin River and the major eastern tributaries, whereas stream flow was less accurately simulated in the western tributaries, which are ephemeral small streams that peak during winter storm events and are mainly fed by irrigation return flow during the growing season. The most sensitive parameters to stream flow were CN2, SOL_AWC, HRU_SLP, SLSUBBSN, SLSOIL, GWQMN and GW_REVAP. Regionalization of parameters is important as the sensitivity of parameters vary significantly spatially. In terms of evaluation metric, NSE tended to overrate model performance when compared to PBIAS. Anticipated results will include (1) pesticide use pattern analysis, (2) calibration and validation of stream flow, sediment, and pesticide loads, and (3) characterization of spatial patterns and temporal trends of pesticide yield.

Prediction of pesticide toxicity in Midwest streams

USGS Publications Warehouse

Shoda, Megan E.; Stone, Wesley W.; Nowell, Lisa H.

2016-01-01

The occurrence of pesticide mixtures is common in stream waters of the United States, and the impact of multiple compounds on aquatic organisms is not well understood. Watershed Regressions for Pesticides (WARP) models were developed to predict Pesticide Toxicity Index (PTI) values in unmonitored streams in the Midwest and are referred to as WARP-PTI models. The PTI is a tool for assessing the relative toxicity of pesticide mixtures to fish, benthic invertebrates, and cladocera in stream water. One hundred stream sites in the Midwest were sampled weekly in May through August 2013, and the highest calculated PTI for each site was used as the WARP-PTI model response variable. Watershed characteristics that represent pesticide sources and transport were used as the WARP-PTI model explanatory variables. Three WARP-PTI models—fish, benthic invertebrates, and cladocera—were developed that include watershed characteristics describing toxicity-weighted agricultural use intensity, land use, agricultural management practices, soil properties, precipitation, and hydrologic properties. The models explained between 41 and 48% of the variability in the measured PTI values. WARP-PTI model evaluation with independent data showed reasonable performance with no clear bias. The models were applied to streams in the Midwest to demonstrate extrapolation for a regional assessment to indicate vulnerable streams and to guide more intensive monitoring.

Beverton-Holt discrete pest management models with pulsed chemical control and evolution of pesticide resistance

NASA Astrophysics Data System (ADS)

Liang, Juhua; Tang, Sanyi; Cheke, Robert A.

2016-07-01

Pest resistance to pesticides is usually managed by switching between different types of pesticides. The optimal switching time, which depends on the dynamics of the pest population and on the evolution of the pesticide resistance, is critical. Here we address how the dynamic complexity of the pest population, the development of resistance and the spraying frequency of pulsed chemical control affect optimal switching strategies given different control aims. To do this, we developed novel discrete pest population growth models with both impulsive chemical control and the evolution of pesticide resistance. Strong and weak threshold conditions which guarantee the extinction of the pest population, based on the threshold values of the analytical formula for the optimal switching time, were derived. Further, we addressed switching strategies in the light of chosen economic injury levels. Moreover, the effects of the complex dynamical behaviour of the pest population on the pesticide switching times were also studied. The pesticide application period, the evolution of pesticide resistance and the dynamic complexity of the pest population may result in complex outbreak patterns, with consequent effects on the pesticide switching strategies.

Seasonal variations in fate and removal of trace organic chemical contaminants while operating a full-scale membrane bioreactor.

PubMed

Trinh, Trang; van den Akker, Ben; Coleman, Heather M; Stuetz, Richard M; Drewes, Jörg E; Le-Clech, Pierre; Khan, Stuart J

2016-04-15

Trace organic chemical (TrOC) contaminants are of concern for finished water from water recycling schemes because of their potential adverse environmental and public health effects. Understanding the impacts of seasonal variations on fate and removal of TrOCs is important for proper operation, risk assessment and management of treatment systems for water recycling such as membrane bioreactors (MBRs). Accordingly, this study investigated the fate and removal of a wide range of TrOCs through a full-scale MBR plant during summer and winter seasons. TrOCs included 12 steroidal hormones, 3 xeno-estrogens, 2 pesticides and 23 pharmaceuticals and personal care products. Seasonal differences in the mechanisms responsible for removing some of the TrOCs were evident. In particular the contribution of biotransformation and biomass adsorption to the overall removal of estrone, bisphenol A, 17β-estradiol and triclosan were consistently different between the two seasons. Substantially higher percentage removal via biotransformation was observed during the summer sampling period, which compensated for a reduction in removal attributed to biomass adsorption. The opposite was observed during winter, where the contribution of biotransformation to the overall removal of these TrOCs had decreased, which was offset by an improvement in biomass adsorption. The exact mechanisms responsible for this shift are unknown, however are likely to be temperature related as warmer temperatures can lower sorption efficiency, yet enhance biotransformation of these TrOCs. Copyright © 2015 Elsevier B.V. All rights reserved.

Molecular Mechanisms of Pesticide-induced Neurotoxicity: Relevance to Parkinson’s Disease

PubMed Central

Franco, Rodrigo; Li, Sumin; Rodriguez-Rocha, Humberto; Burns, Michaela; Panayiotidis, Mihalis I.

2010-01-01

Pesticides are widely used in agricultural and other settings, resulting in continued human exposure. Pesticide toxicity has been clearly demonstrated to alter a variety of neurological functions. Particularly, there is strong evidence suggesting that pesticide exposure predisposes to neurodegenerative diseases. Epidemiological data has suggested a relationship between pesticide exposure and brain neurodegeneration. However, an increasing debate has aroused regarding this issue. Paraquat is a highly toxic quaternary nitrogen herbicide which has been largely studied as a model for Parkinson’s disease providing valuable insight into the possible mechanisms involved in the toxic effects of pesticides and their role in the progression of neurodegenerative diseases. In this work, we review the molecular mechanisms involved in the neurotoxic actions of pesticides, with a particular emphasis on the mechanisms associated with the induction neuronal cell death by paraquat as a model for Parkinsonian neurodegeneration. PMID:20542017

BETR Global - A geographically explicit global-scale multimedia contaminant fate model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Macleod, M.; Waldow, H. von; Tay, P.

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).

Dose-additivity modeling for acute and repeated exposure to a mixture of N-methycarbamate Pesticides

EPA Science Inventory

The toxicity of N-methylcarbamate pesticides is attributed to the reversible inhibition of cholinesterase (ChE) enzymes in the central and peripheral nervous system. The inhibition of ChE following a single exposure to this class of pesticides has been modeled using a dose-additi...

Using Model Ecosystems to Predict the Environmental Behavior of Pesticides

ERIC Educational Resources Information Center

Booth, Gary M.

1977-01-01

Describes construction of a model ecosystem using a 10-gallon aquarium with a sand, water and air interface. Pesticides are placed on sorghum plants grown on the terrestrial portion. After 30 days, movement of the pesticide is traced using radioisotope techniques, from terrestrial to aquatic organisms. Details for calculating concentration factors…

Geographic Model and Biomarker-Derived Measures of Pesticide Exposure and Parkinson’s Disease

PubMed Central

RITZ, BEATE; COSTELLO, SADIE

2013-01-01

For more than two decades, reports have suggested that pesticides and herbicides may be an etiologic factor in idiopathic Parkinson’s disease (PD). To date, no clear associations with any specific pesticide have been demonstrated from epidemiological studies perhaps, in part, because methods of reliably estimating exposures are lacking. We tested the validity of a Geographic Information Systems (GIS)-based exposure assessment model that estimates potential environmental exposures at residences from pesticide applications to agricultural crops based on California Pesticide Use Reports (PUR). Using lipid-adjusted dichlorodiphenyldichloroethylene (DDE) serum levels as the “gold standard” for pesticide exposure, we conducted a validation study in a sample taken from an ongoing, population-based case–control study of PD in Central California. Residential, occupational, and other risk factor data were collected for 22 cases and 24 controls from Kern county, California. Environmental GIS–PUR-based organochlorine (OC) estimates were derived for each subject and compared to lipid-adjusted DDE serum levels. Relying on a linear regression model, we predicted log-transformed lipid-adjusted DDE serum levels. GIS–PUR-derived OC measure, body mass index, age, gender, mixing and loading pesticides by hand, and using pesticides in the home, together explained 47% of the DDE serum level variance (adjusted r2 = 0.47). The specificity of using our environmental GIS–PUR-derived OC measures to identify those with high-serum DDE levels was reasonably good (87%). Our environmental GIS–PUR-based approach appears to provide a valid model for assessing residential exposures to agricultural pesticides. PMID:17119217

Sensitivity analyses for simulating pesticide impacts on honey bee colonies

USDA-ARS?s Scientific Manuscript database

We employ Monte Carlo simulation and sensitivity analysis techniques to describe the population dynamics of pesticide exposure to a honey bee colony using the VarroaPop+Pesticide model. Simulations are performed of hive population trajectories with and without pesticide exposure to determine the eff...

75 FR 60113 - Pesticide Science Policy; Notice of Withdrawal

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-29

... ENVIRONMENTAL PROTECTION AGENCY [EPA-HQ-OPP-2008-0935; FRL-8804-7] Pesticide Science Policy... announces the withdrawal of the pesticide science policy document ``Use of the Pesticide Data Program (PDP... of data and different models. This science policy document was developed to explain a particular...

Pesticides are Associated with Allergic and Non-Allergic Wheeze among Male Farmers

PubMed Central

Hoppin, Jane A.; Umbach, David M.; Long, Stuart; London, Stephanie J.; Henneberger, Paul K.; Blair, Aaron; Alavanja, Michael; Freeman, Laura E. Beane; Sandler, Dale P.

2016-01-01

Background: Growing evidence suggests that pesticide use may contribute to respiratory symptoms. Objective: We evaluated the association of currently used pesticides with allergic and non-allergic wheeze among male farmers. Methods: Using the 2005–2010 interview data of the Agricultural Health Study, a prospective study of farmers in North Carolina and Iowa, we evaluated the association between allergic and non-allergic wheeze and self-reported use of 78 specific pesticides, reported by ≥ 1% of the 22,134 men interviewed. We used polytomous regression models adjusted for age, BMI, state, smoking, and current asthma, as well as for days applying pesticides and days driving diesel tractors. We defined allergic wheeze as reporting both wheeze and doctor-diagnosed hay fever (n = 1,310, 6%) and non-allergic wheeze as reporting wheeze but not hay fever (n = 3,939, 18%); men without wheeze were the referent. Results: In models evaluating current use of specific pesticides, 19 pesticides were significantly associated (p < 0.05) with allergic wheeze (18 positive, 1 negative) and 21 pesticides with non-allergic wheeze (19 positive, 2 negative); 11 pesticides were associated with both. Seven pesticides (herbicides: 2,4-D and simazine; insecticides: carbaryl, dimethoate, disulfoton, and zeta-cypermethrin; and fungicide pyraclostrobin) had significantly different associations for allergic and non-allergic wheeze. In exposure–response models with up to five exposure categories, we saw evidence of an exposure–response relationship for several pesticides including the commonly used herbicides 2,4-D and glyphosate, the insecticides permethrin and carbaryl, and the rodenticide warfarin. Conclusions: These results for farmers implicate several pesticides that are commonly used in agricultural and residential settings with adverse respiratory effects. Citation: Hoppin JA, Umbach DM, Long S, London SJ, Henneberger PK, Blair A, Alavanja M, Beane Freeman LE, Sandler DP. 2017. Pesticides are associated with allergic and non-allergic wheeze among male farmers. Environ Health Perspect 125:535–543; http://dx.doi.org/10.1289/EHP315 PMID:27384423

STATE WATER RESOURCES RESEARCH INSTITUTE PROGRAM: GROUND WATER RESEARCH.

USGS Publications Warehouse

Burton, James S.; ,

1985-01-01

This paper updates a review of the accomplishments of the State Water Resources Research Program in ground water contamination research. The aim is to assess the progress made towards understanding the mechanisms of ground water contamination and based on this understanding, to suggest procedures for the prevention and control of ground water contamination. The following research areas are covered: (1) mechanisms of organic contaminant transport in the subsurface environment; (2) bacterial and viral contamination of ground water from landfills and septic tank systems; (3) fate and persistence of pesticides in the subsurface; (4) leachability and transport of ground water pollutants from coal production and utilization; and (5) pollution of ground water from mineral mining activities.

Volatility of ten priority pollutants from fortified avian toxicity test diets

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCrady, J.K.; Johnson, D.E.; Turner, L.W.

1985-01-01

With a few important exceptions, most pesticides have low volatility. However, a significant number of the industrial chemicals under the jurisdiction of TSCA have sufficient volatility to affect availability in fortified test diets and consequently the test results. Although extremely volatile chemicals might evaportate from test diets, there is insufficient data to indicate what levels of volatility are of concern. Volatility may be only one of a variety of factors influencing the fate of organic chemicals in test diets. Other mechanisms such as hydrolysis, adsorption, and photolysis should also be considered, but for many chemicals having significant vapor pressures, volatilitymore » is likely to be the major source of loss.« less

Design and testing of a process-based groundwater vulnerability assessment (P-GWAVA) system for predicting concentrations of agrichemicals in groundwater across the United States

USGS Publications Warehouse

Barbash, Jack E; Voss, Frank D.

2016-03-29

Efforts to assess the likelihood of groundwater contamination from surface-derived compounds have spanned more than three decades. Relatively few of these assessments, however, have involved the use of process-based simulations of contaminant transport and fate in the subsurface, or compared the predictions from such models with measured data—especially over regional to national scales. To address this need, a process-based groundwater vulnerability assessment (P-GWAVA) system was constructed to use transport-and-fate simulations to predict the concentration of any surface-derived compound at a specified depth in the vadose zone anywhere in the conterminous United States. The system was then used to simulate the concentrations of selected agrichemicals in the vadose zone beneath agricultural areas in multiple locations across the conterminous United States. The simulated concentrations were compared with measured concentrations of the compounds detected in shallow groundwater (that is, groundwater drawn from within a depth of 6.3 ± 0.5 meters [mean ± 95 percent confidence interval] below the water table) in more than 1,400 locations across the United States. The results from these comparisons were used to select the simulation approaches that led to the closest agreement between the simulated and the measured concentrations.The P-GWAVA system uses computer simulations that account for a broader range of the hydrologic, physical, biological and chemical phenomena known to control the transport and fate of solutes in the subsurface than has been accounted for by any other vulnerability assessment over regional to national scales. Such phenomena include preferential transport and the influences of temperature, soil properties, and depth on the partitioning, transport, and transformation of pesticides in the subsurface. Published methods and detailed soil property data are used to estimate a wide range of model input parameters for each site, including surface albedo, surface crust permeability, soil water content, Brooks-Corey parameters, saturated hydraulic conductivity, macroporosity and sizes of microbial populations, as well as solute partition coefficients, reaction rates, and meso-micropore diffusion rates. To ensure geographic consistency among the predictions, the only site-specific input data that are used are those that are available for all of the 48 conterminous states.

Organophosphorus (OP) Pesticide Degradation in the Presence of Chlorinated Oxidants: Kinetics, Modeling, and Structure-Activity Relationships

EPA Science Inventory

The rates and pathways for pesticide transformation during drinking water treatment are known for only a few pesticides and under limited conditions. The resulting oxons are more toxic than the parent pesticides. The transformation rates and pathways for chlorpyrifos, an OP pest...

Walking the California County Lines with Pesticides on the Mind - A Tale of Two Cities

EPA Science Inventory

California has numerous aquatic threatened and endangered species and there is evidence that these species may be affected by non-target pesticide runoff. Modeling can play an important role in assessing the impact of pesticides but it requires complete data on pesticide use, mo...

Prioritization of pesticides based on daily dietary exposure potential as determined from the SHEDS model

EPA Science Inventory

A major pathway for exposure to many pesticides is through diet. The objectives were to rank pesticides by comparing their calculated daily dietary exposure as determined by EPA's Stochastic Human Exposure and Dose Simulation (SHEDS) to single pesticides for different age groups ...

Modeling Flight Attendants’ Exposures to Pesticide in Disinsected Aircraft Cabins

PubMed Central

Zhang, Yong; Isukapalli, Sastry; Georgopoulos, Panos; Weisel, Clifford

2014-01-01

Aircraft cabin disinsection is required by some countries to kill insects that may pose risks to public health and native ecological systems. A probabilistic model has been developed by considering the microenvironmental dynamics of the pesticide in conjunction with the activity patterns of flight attendants, to assess their exposures and risks to pesticide in disinsected aircraft cabins under three scenarios of pesticide application. Main processes considered in the model are microenvironmental transport and deposition, volatilization, and transfer of pesticide when passengers and flight attendants come in contact with the cabin surfaces. The simulated pesticide airborne mass concentration and surface mass loadings captured measured ranges reported in the literature. The medians (means±standard devitions) of daily total exposures intakes were 0.24 (3.8±10.0), 1.4 (4.2±5.7) and 0.15 (2.1±3.2) μg/(day kg BW) for scenarios of Residual Application, Preflight and Top-of-Descent spraying, respectively. Exposure estimates were sensitive to parameters corresponding to pesticide deposition, body surface area and weight, surface-to-body transfer efficiencies, and efficiency of adherence to skin. Preflight spray posed 2.0 and 3.1 times higher pesticide exposure risk levels for flight attendants in disinsected aircraft cabins than Top-of-Descent spray and Residual Application, respectively. PMID:24251734

Threshold conditions for integrated pest management models with pesticides that have residual effects.

PubMed

Tang, Sanyi; Liang, Juhua; Tan, Yuanshun; Cheke, Robert A

2013-01-01

Impulsive differential equations (hybrid dynamical systems) can provide a natural description of pulse-like actions such as when a pesticide kills a pest instantly. However, pesticides may have long-term residual effects, with some remaining active against pests for several weeks, months or years. Therefore, a more realistic method for modelling chemical control in such cases is to use continuous or piecewise-continuous periodic functions which affect growth rates. How to evaluate the effects of the duration of the pesticide residual effectiveness on successful pest control is key to the implementation of integrated pest management (IPM) in practice. To address these questions in detail, we have modelled IPM including residual effects of pesticides in terms of fixed pulse-type actions. The stability threshold conditions for pest eradication are given. Moreover, effects of the killing efficiency rate and the decay rate of the pesticide on the pest and on its natural enemies, the duration of residual effectiveness, the number of pesticide applications and the number of natural enemy releases on the threshold conditions are investigated with regard to the extent of depression or resurgence resulting from pulses of pesticide applications and predator releases. Latin Hypercube Sampling/Partial Rank Correlation uncertainty and sensitivity analysis techniques are employed to investigate the key control parameters which are most significantly related to threshold values. The findings combined with Volterra's principle confirm that when the pesticide has a strong effect on the natural enemies, repeated use of the same pesticide can result in target pest resurgence. The results also indicate that there exists an optimal number of pesticide applications which can suppress the pest most effectively, and this may help in the design of an optimal control strategy.

Modeling the risk of water pollution by pesticides from imbalanced data.

PubMed

Trajanov, Aneta; Kuzmanovski, Vladimir; Real, Benoit; Perreau, Jonathan Marks; Džeroski, Sašo; Debeljak, Marko

2018-04-30

The pollution of ground and surface waters with pesticides is a serious ecological issue that requires adequate treatment. Most of the existing water pollution models are mechanistic mathematical models. While they have made a significant contribution to understanding the transfer processes, they face the problem of validation because of their complexity, the user subjectivity in their parameterization, and the lack of empirical data for validation. In addition, the data describing water pollution with pesticides are, in most cases, very imbalanced. This is due to strict regulations for pesticide applications, which lead to only a few pollution events. In this study, we propose the use of data mining to build models for assessing the risk of water pollution by pesticides in field-drained outflow water. Unlike the mechanistic models, the models generated by data mining are based on easily obtainable empirical data, while the parameterization of the models is not influenced by the subjectivity of ecological modelers. We used empirical data from field trials at the La Jaillière experimental site in France and applied the random forests algorithm to build predictive models that predict "risky" and "not-risky" pesticide application events. To address the problems of the imbalanced classes in the data, cost-sensitive learning and different measures of predictive performance were used. Despite the high imbalance between risky and not-risky application events, we managed to build predictive models that make reliable predictions. The proposed modeling approach can be easily applied to other ecological modeling problems where we encounter empirical data with highly imbalanced classes.

Mechanisms and pathways of aniline elimination from aquatic environments.

PubMed Central

Lyons, C D; Katz, S; Bartha, R

1984-01-01

The fate of aniline, a representative of arylamine pollutants derived from the manufacture of dyes, coal liquefaction, and pesticide degradation, was comprehensively evaluated by use of unpolluted and polluted pond water as model environments. Evaporation plus autoxidation proved to be minor elimination mechanisms, removing ca. 1% of the added aniline per day. Instantaneous binding to humic components of a 0.1% sewage sludge inoculum removed 4%. Biodegradation of aniline in pond water was accelerated by the sewage sludge inoculum. A substantial portion of the degraded aniline carbon was mineralized to CO2 within a 1-week period, and microbial biomass was formed as a result of aniline utilization. Biodegradation was clearly the most significant removal mechanism of polluting aniline from pond water. A gas chromatographic-mass spectrometric analysis of biodegradation intermediates revealed that the major pathway of aniline biodegradation in pond water involved oxidative deamination to catechol, which was further metabolized through cis,cis-muconic, beta-ketoadipic, levulinic, and succinic acid intermediates to CO2. Minor biodegradation pathways involved reversible acylation to acetanilide and formanilide, whereas N-oxidation resulted in small amounts of oligomeric condensation products. PMID:6497369

Three-Dimensional Subsurface Flow, Fate and Transport of Microbes and Chemicals (3DFATMIC) Model

EPA Pesticide Factsheets

This model simulates subsurface flow, fate and transport of contaminants that are undergoing chemical or biological transformations. The model is applicable to transient conditions in both saturated and unsaturated zones.

Two-Dimensional Subsurface Flow, Fate and Transport of Microbes and Chemicals (2DFATMIC) Model

EPA Pesticide Factsheets

This model simulates subsurface flow, fate, and transport of contaminants that are undergoing chemical or biological transformations. This model is applicable to transient conditions in both saturated and unsaturated zones.

Effect of biochar and digestate on microbial respiration and pesticide degradation

NASA Astrophysics Data System (ADS)

Mukherjee, Santanu; Tappe, Wolfgang; Hofmann, Diana; Köppchen, Stephan; Disko, Ulrich; Weihermüller, Lutz; Burauel, Peter; Vereecken, Harry

2014-05-01

To overcome the problem of on farm point sources of pollution stemming from improper handling, spillages, and leakages of pesticides during filling and cleaning of spraying equipment, environmental friendly and low cost technology filter systems are currently under development. Based on a laboratory screening approach, where different biomixtures (soil, with biochar and/or digestate) are tested a full scale outdoor system will be developed. Therefore, different fundamental processes like pesticide mineralization, metabolization, sorption-desorption, and transport behavior of three radiolabelled pesticides (Bentazone, Boscalid and Pyrimethanil) will be investigated. Biochar and digestate mixtures with two contrasting soils (sandy and silt loam) had been used as a novel biofilter material for respiration study instead of conventional soil and straw mixtures. To analyze the pesticide degradation potential and to gain information about the temporal evolution of the degradation process of the biochar and digestate soil mixtures microbial respiration was measured over the course of three month. As expected, digestate acts as an easily available C-source leading to highest release of CO2 compared to other biomixtures used. In contrast, the addition of even small amounts (1 %) of biochar caused a profound suppression in the CO2 release from digestate based mixtures. The exact driving mechanism for this suppression can be manifold likes negative priming or chemisorption of CO2 on biochar or NH3 toxicity induced by the large amount of digestate applied in the experiment (30 %) or can be combination of all effects. Surprisingly, a repeated experiment with same but aged digestate did not show such negative priming. On the other hand, the fate of applied organic contaminants to biomixtures depends on several factors like soil properties and climatic conditions as well as biological degradation. To analyze the degradation potential of the different soil/amendment mixtures a degradation study was performed to determine the effects of biochar and digestate in different mixing rates on the metabolization behavior of the studied pesticides, and to identify and quantify the metabolites derived during the degradation process. The results from the 14C Bentazone study indicate that 5 % digestate and 5 % biochar mixture showed highest (nearly~ 15 %) and 1 % biochar lowest rate of mineralization (~1 %), whereby highest microbial activity was measured in the soil/digestate mixture.

Pesticide exposure and end-stage renal disease risk among wives of pesticide applicators in the Agricultural Health Study✩

PubMed Central

Lebov, Jill F.; Engel, Lawrence S.; Richardson, David; Hogan, Susan L.; Sandler, Dale P.; Hoppin, Jane A.

2015-01-01

Background Pesticide exposure has been found to cause renal damage and dysfunction in experimental studies, but epidemiological research on the renal effects of chronic low-level pesticide exposure is limited. We investigated the relationships between end-stage renal disease (ESRD) among wives of licensed pesticide applicators (N = 31,142) in the Agricultural Health Study (AHS) and (1) personal pesticide use, (2) exposure to the husband's pesticide use, and (3) other pesticide-associated farming and household activities. Methods AHS participants reported pesticide exposure via self-administered questionnaires at enrollment (1993–1997). ESRD cases were identified via linkage to the United States Renal Data System. Associations between ESRD and pesticide exposures were estimated with Cox proportional hazard regression models controlling for age at enrollment. Models of associations with farming and household factors were additionally adjusted for personal use of pesticides. Results We identified 98 ESRD cases diagnosed between enrollment and 31 December 2011. Although women who ever applied pesticides (56% of cohort) were less likely than those who did not apply to develop ESRD (Hazard Ratio (HR): 0.42; 95% CI: 0.28, 0.64), among women who did apply pesticides, the rate of ESRD was significantly elevated among those who reported the highest (vs. lowest) cumulative general pesticide use (HR: 4.22; 95% CI: 1.26, 14.20). Among wives who never applied pesticides, ESRD was associated with husbands' ever use of paraquat (HR = 1.99; 95% CI: 1.14, 3.47) and butylate (HR = 1.71; 95% CI: 1.00, 2.95), with a positive exposure–response pattern for husband’s cumulative use of these pesticides. Conclusions ESRD may be associated with direct and/or indirect exposure to pesticides among farm women. Future studies should evaluate indirect exposure risk among other rural populations. PMID:26505650

Absorption of current use pesticides by snapping turtle (Chelydra serpentina) eggs in treated soil.

PubMed

Solla, Shane Raymond de; Martin, Pamela Anne

2011-10-01

Reptiles often breed within agricultural and urban environments that receive frequent pesticide use. Consequently, their eggs and thus developing embryos may be exposed to pesticides. Our objectives were to determine (i) if turtle eggs are capable of absorbing pesticides from treated soil, and (ii) if pesticide absorption rates can be predicted by their chemical and physical properties. Snapping turtle (Chelydra serpentina) eggs were incubated in soil that was treated with 10 pesticides (atrazine, simazine, metolachlor, azinphos-methyl, dimethoate, chlorpyrifos, carbaryl, endosulfan (I and II), captan, and chlorothalonil). There were two treatments, consisting of pesticides applied at application rate equivalents of 1.92 or 19.2 kg a.i/ha. Eggs were removed after one and eight days of exposure and analyzed for pesticides using gas chromatography coupled with a mass selective detector (GC-MSD) or high performance liquid chromatography (HPLC). Absorption of pesticides in eggs from soil increased with both magnitude and duration of exposure. Of the 10 pesticides, atrazine and metolachlor generally had the greatest absorption, while azinphos-methyl had the lowest. Chlorothalonil was below detection limits at both exposure rates. Our preliminary model suggests that pesticides having the highest absorption into eggs tended to have both low sorption to organic carbon or lipids, and high water solubility. For pesticides with high water solubility, high vapor pressure may also increase absorption. As our model is preliminary, confirmatory studies are needed to elucidate pesticide absorption in turtle eggs and the potential risk they may pose to embryonic development. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

UNITED STATES METEOROLOGICAL DATA - DAILY AND HOURLY FILES TO SUPPORT PREDICTIVE EXPOSURE MODELING

EPA Science Inventory

ORD numerical models for pesticide exposure include a model of spray drift (AgDisp), a cropland pesticide persistence model (PRZM), a surface water exposure model (EXAMS), and a model of fish bioaccumulation (BASS). A unified climatological database for these models has been asse...

Assessment of chemical fate in the environment using evaluative, regional and local-scale models: Illustrative application to chlorobenzene and linear alkylbenzene sulfonates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mackay, D.; Di Guardo, A.; Paterson, S.

Evaluation of chemical fate in the environment has been suggested to be best accomplished using a five-stage process in which a sequence of increasing site-specific multimedia mass balance models is applied. This approach is illustrated for chlorobenzene and linear alkylbenzene sulfonates (LAS). The first two stages involve classifying the chemical and quantifying the emissions into each environmental compartment. In the third stage, the characteristics of the chemical are determined using the evaluative equilibrium criterion model, which is capable of treating a variety of chemicals including those that are in volatile and insoluble in water. This evaluation is conducted in threemore » steps using levels 1, 2, and 3 versions of the model, which introduce increasing complexity and more realistic representations of the environment. In the fourth stage, ChemCAN, which is a level 3 model for specific regions of Canada, is used to predict the chemical`s fate in southern Ontario. The final stage is to apply local environmental models to predict environmental exposure concentrations. For chlorobenzene, the local model was the SoilFug model, which predicts the fate of agrochemicals, and for LAS the WW-TREAT, GRiDS, and ROUT models were used to predict the fate of LAS in a sewage treatment plant and in riverine receiving waters. It is concluded that this systematic approach provides a comprehensive assessment of chemical fate, revealing the broad characteristics of chemical behavior and quantifying the likely local and regional exposure levels.« less

Kinetics of heterogeneous chemical reactions: a theoretical model for the accumulation of pesticides in soil.

PubMed

Lin, S H; Sahai, R; Eyring, H

1971-04-01

A theoretical model for the accumulation of pesticides in soil has been proposed and discussed from the viewpoint of heterogeneous reaction kinetics with a basic aim to understand the complex nature of soil processes relating to the environmental pollution. In the bulk of soil, the pesticide disappears by diffusion and a chemical reaction; the rate processes considered on the surface of soil are diffusion, chemical reaction, vaporization, and regular pesticide application. The differential equations involved have been solved analytically by the Laplace-transform method.

Kinetics of Heterogeneous Chemical Reactions: A Theoretical Model for the Accumulation of Pesticides in Soil

PubMed Central

Lin, S. H.; Sahai, R.; Eyring, H.

1971-01-01

A theoretical model for the accumulation of pesticides in soil has been proposed and discussed from the viewpoint of heterogeneous reaction kinetics with a basic aim to understand the complex nature of soil processes relating to the environmental pollution. In the bulk of soil, the pesticide disappears by diffusion and a chemical reaction; the rate processes considered on the surface of soil are diffusion, chemical reaction, vaporization, and regular pesticide application. The differential equations involved have been solved analytically by the Laplace-transform method. PMID:5279519

Caenorhabditis elegans vulval cell fate patterning

NASA Astrophysics Data System (ADS)

Félix, Marie-Anne

2012-08-01

The spatial patterning of three cell fates in a row of competent cells is exemplified by vulva development in the nematode Caenorhabditis elegans. The intercellular signaling network that underlies fate specification is well understood, yet quantitative aspects remain to be elucidated. Quantitative models of the network allow us to test the effect of parameter variation on the cell fate pattern output. Among the parameter sets that allow us to reach the wild-type pattern, two general developmental patterning mechanisms of the three fates can be found: sequential inductions and morphogen-based induction, the former being more robust to parameter variation. Experimentally, the vulval cell fate pattern is robust to stochastic and environmental challenges, and minor variants can be detected. The exception is the fate of the anterior cell, P3.p, which is sensitive to stochastic variation and spontaneous mutation, and is also evolving the fastest. Other vulval precursor cell fates can be affected by mutation, yet little natural variation can be found, suggesting stabilizing selection. Despite this fate pattern conservation, different Caenorhabditis species respond differently to perturbations of the system. In the quantitative models, different parameter sets can reconstitute their response to perturbation, suggesting that network variation among Caenorhabditis species may be quantitative. Network rewiring likely occurred at longer evolutionary scales.

Assessing intrinsic and specific vulnerability models ability to indicate groundwater vulnerability to groups of similar pesticides: A comparative study

USGS Publications Warehouse

Douglas, Steven; Dixon, Barnali; Griffin, Dale W.

2018-01-01

With continued population growth and increasing use of fresh groundwater resources, protection of this valuable resource is critical. A cost effective means to assess risk of groundwater contamination potential will provide a useful tool to protect these resources. Integrating geospatial methods offers a means to quantify the risk of contaminant potential in cost effective and spatially explicit ways. This research was designed to compare the ability of intrinsic (DRASTIC) and specific (Attenuation Factor; AF) vulnerability models to indicate groundwater vulnerability areas by comparing model results to the presence of pesticides from groundwater sample datasets. A logistic regression was used to assess the relationship between the environmental variables and the presence or absence of pesticides within regions of varying vulnerability. According to the DRASTIC model, more than 20% of the study area is very highly vulnerable. Approximately 30% is very highly vulnerable according to the AF model. When groundwater concentrations of individual pesticides were compared to model predictions, the results were mixed. Model predictability improved when concentrations of the group of similar pesticides were compared to model results. Compared to the DRASTIC model, the AF model more accurately predicts the distribution of the number of contaminated wells within each vulnerability class.

The influence of size on the toxicity of an encapsulated pesticide: a comparison of micron- and nano-sized capsules.

PubMed

Meredith, Alicea N; Harper, Bryan; Harper, Stacey L

2016-01-01

Encapsulation technology involves entrapping a chemical active ingredient (a.i.) inside a hollow polymeric shell and has been applied to commercial pesticide manufacturing for years to produce capsule suspension (CS) formulations with average particle sizes in the micron-scale. The few literature sources that investigate the environmental fate and toxicity to non-target organisms of encapsulated commercially available pesticide products with regard to capsule size report on average sizes between 20 and 50 μm. Here, we have identified a CS formulation with an average capsule size of approximately 2 μm with some capsules extending into the nanometer scale (~200 nm). Determining how carrier size influences toxicity is important to understanding if current pesticide risk assessments are sufficient to protect against products that incorporate encapsulation technology. Here, a commercial pyrethroid CS pesticide with lambda-cyhalothrin (λ-Cy) as the a.i. was separated into two suspensions, a fraction consisting of nano-sized capsules (~250 nm) and a fraction of micron-sized capsules (~2200 nm) in order to investigate the influence of capsule size on toxicity to embryonic zebrafish, Danio rerio. Toxicity was evaluated 24h after exposure to equivalent amounts of a.i. by the presence and severity of pyrethroid-specific tremors, 14 sublethal developmental impacts and mortality. Fish exposed to greater than 20 μg a.i. L(-1) technical λ-Cy or formulated product experienced curvature of the body axis, pericardial edema, craniofacial malformations, and mortality. Exposure to the unfractionated formulation, micro fraction, nano fraction and technical a.i. resulted in no significant differences in the occurrence of sublethal impacts or mortality; however, the technical a.i. exposure resulted in significantly less fish experiencing tremors and shorter tremors compared to any of the formulated product exposures. This suggests that the capsule size does not influence the toxic response of the entrapped λ-Cy, but the presence or absence of the capsules does. Testing across other encapsulated products is needed to determine if size does not have influence on toxicity regardless of encapsulation technology. Copyright © 2015 Elsevier Ltd. All rights reserved.

Determination of pesticide and phthalate residues in tea by QuEChERS method and their fate in processing.

PubMed

Yadav, Sapna; Rai, Satyajeet; Srivastava, Ashutosh K; Panchal, Smita; Patel, D K; Sharma, V P; Jain, Sudha; Srivastava, L P

2017-01-01

In this study, the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was applied for the analysis of the multiclass pesticide residues of 12 organochlorines (OCs), 9 organophosphates (OPs), 11 synthetic pyrethroids (SPs), 4 herbicides, 6 phthalates in raw tea (loose tea, branded tea and herbal tea), and tea infusion in 4 different containers (glass cup, earthen cup, plastic bag and disposal cup). In loose tea and branded tea residues, malathion (0.257 and 0.118 mg kg -1 ), cypermethrin (0.065 and 0.030 mg kg -1 ), and fenvalerate (0.032 and 0.030 mg kg -1 ) were detected, respectively. In herbal tea, residues of only cypermethrin (0.053 mg kg -1 ) and fenvalerate (0.045 mg kg -1 ) were detected. Tea infusion samples contained in a plastic bag were found to be contaminated with only dibutyl phthalate (DBP) (0.038 mg kg -1 ). Disposable cup was found to be contaminated with DBP (0.026 mg kg -1 ) and diethyl phthalate (DEP) (0.004 mg kg -1 ). Further, to know the processing behavior of pesticides, the spiked raw tea was subjected to tea infusion at different brewing times (2, 5, 10 min). The analysis demonstrated that dimethoate, dichlorvos, and malathion had shown more than 10 % of translocation at 5 min of brewing time. Further brewing for 10 min revealed the reduction in concentration of pesticides. Leaching of phthalate residues from different plastic containers was also studied at 10, 30, and 60 min. DBP, benzyl butyl phthalate (BzBP), and di-2-(ethylhexyl) phthalate (DEHP) were leached in the tea infusion samples packed in plastic bags. On the other hand, in disposable cups, leaching of DBP, DEP, and dimethyl phthalate were found. The concentration of phthalate residues increased with retention time. Pesticide and phthalate contaminants were recorded at low quantities in few samples only.

Occurrence, fate and removal of pharmaceuticals, personal care products and pesticides in wastewater stabilization ponds and receiving rivers in the Nzoia Basin, Kenya.

PubMed

K'oreje, Kenneth Otieno; Kandie, Faith Jebiwot; Vergeynst, Leendert; Abira, Margaret Akinyi; Van Langenhove, Herman; Okoth, Maurice; Demeestere, Kristof

2018-05-08

Although there is increased global environmental concern about emerging organic micropollutants (EOMPs) such as pharmaceuticals, personal care products (PPCPs) and polar pesticides, limited information is available on their occurrence in Africa. This study presents unique data on concentrations and loads of 31 PPCPs and 10 pesticides in four wastewater stabilization ponds (WSPs) and receiving rivers (flowing through urban centres) in Kenya. The WSPs indicate a high potential to remove pharmaceutically active compounds (PhACs) with removals by up to >4 orders of magnitude (>99.99% removal), mainly occurring at the facultative stage. However, there are large differences in removal among the different classes, and a shift in the relative PhACs occurrence is observed during wastewater treatment. Whereas the influent is dominated by high-consumption PhACs like anti-inflammatory drugs (e.g. paracetamol and ibuprofen, up to 1000 μg L -1 ), the most recalcitrant PhACs including mainly antibiotics (e.g. sulfadoxin and sulfamethoxazole) and antiretrovirals (e.g. lamivudine and nevirapine) are largely abundant (up to 100 μg L -1 ) in treated effluent. Overall, concentrations of EOMPs in the Nzoia Basin rivers are the highest in dry season (except pesticides) and in small tributaries. They are of the same order of magnitude as those measured in the western world, but clearly lower than what we recently measured in the Ngong River, Nairobi region. Based on the specific consumption patterns and recalcitrant behavior, high concentrations (>1000 ng L -1 ) are observed in the rivers for PPCPs like lamivudine, zidovudine, sulfamethoxazole and methylparaben. Concentration levels of pesticides are in general one order of magnitude lower (<250 ng L -1 ). Our data suggest a continuous input of EOMPs to the rivers from both point (WSPs) and diffuse (urban centres) sources. To better understand and manage the impact of both sources, EOMP removal mechanisms in WSPs and their attenuation in rivers merit further research. Copyright © 2018 Elsevier B.V. All rights reserved.

Estimation of pyrethroid pesticide intake using regression ...

EPA Pesticide Factsheets

Population-based estimates of pesticide intake are needed to characterize exposure for particular demographic groups based on their dietary behaviors. Regression modeling performed on measurements of selected pesticides in composited duplicate diet samples allowed (1) estimation of pesticide intakes for a defined demographic community, and (2) comparison of dietary pesticide intakes between the composite and individual samples. Extant databases were useful for assigning individual samples to composites, but they could not provide the breadth of information needed to facilitate measurable levels in every composite. Composite sample measurements were found to be good predictors of pyrethroid pesticide levels in their individual sample constituents where sufficient measurements are available above the method detection limit. Statistical inference shows little evidence of differences between individual and composite measurements and suggests that regression modeling of food groups based on composite dietary samples may provide an effective tool for estimating dietary pesticide intake for a defined population. The research presented in the journal article will improve community's ability to determine exposures through the dietary route with a less burdensome and costly method.

Water-quality, water-level, and discharge data associated with the Mississippi embayment agricultural chemical-transport study, 2006-2008

USGS Publications Warehouse

Dalton, Melinda S.; Rose, Claire E.; Coupe, Richard H.

2010-01-01

In 2006, the Agricultural Chemicals: Sources, Transport and Fate study team (Agricultural Chemicals Team, ACT) of the U.S. Geological Survey National Water-Quality Assessment Program began a study in northwestern Mississippi to evaluate the influence of surface-water recharge on the occurrence of agriculturally related nutrients and pesticides in the Mississippi River Valley alluvial aquifer. The ACT study was composed in the Bogue Phalia Basin, an indicator watershed within the National Water-Quality Assessment Program Mississippi Embayment Study Unit and utilized several small, subbasins within the Bogue Phalia to evaluate surface and groundwater interaction and chemical transport in the Basin. Data collected as part of this ACT study include water-quality data from routine and incident-driven water samples evaluated for major ions, nutrients, organic carbon, physical properties, and commonly used pesticides in the area; discharge, gage height and water-level data for surface-water sites, the shallow alluvial aquifer, and hyporheic zone; additionally, agricultural data and detailed management activities were reported by land managers for farms within two subbasins of the Bogue Phalia Basin—Tommie Bayou at Pace, MS, and an unnamed tributary to Clear Creek near Napanee, MS.

Biodegradation and toxicity of a maize herbicide mixture: mesotrione, nicosulfuron and S-metolachlor.

PubMed

Carles, Louis; Joly, Muriel; Bonnemoy, Frédérique; Leremboure, Martin; Donnadieu, Florence; Batisson, Isabelle; Besse-Hoggan, Pascale

2018-04-21

The prediction of chemical mixture toxicity is a major concern regarding unintentional mixture of pesticides from agricultural lands treated with various such compounds. We focused our work on a mixture of three herbicides commonly applied on maize crops within a fortnight, namely mesotrione (β-triketone), nicosulfuron (sulfonylurea) and S-metolachlor (chloroacetanilide). The metabolic pathways of mesotrione and nicosulfuron were qualitatively and quantitatively determined with a bacterial strain (Bacillus megaterium Mes11). This strain was isolated from an agricultural soil and able to biotransform both these herbicides. Although these pathways were unaffected in the case of binary or ternary herbicide mixtures, kinetics of nicosulfuron disappearance and also of mesotrione and nicosulfuron metabolite formation was strongly modulated. The toxicity of the parent compounds and metabolites was evaluated for individual compounds and mixtures with the standardized Microtox® test. Synergistic interactions were evidenced for all the parent compound mixtures. Synergistic, antagonistic or additive toxicity was obtained depending on the metabolite mixture. Overall, these results emphasize the need to take into account the active ingredient and metabolites all together for the determination of environmental fate and toxicity of pesticide mixtures. Copyright © 2018 Elsevier B.V. All rights reserved.

BETR North America: A regionally segmented multimedia contaminant fate model for North America

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacLeod, M.; Woodfine, D.G.; Mackay, D.

We present the Berkeley-Trent North American contaminant fate model (BETR North America), a regionally segmented multimedia contaminant fate model based on the fugacity concept. The model is built on a framework that links contaminant fate models of individual regions, and is generally applicable to large, spatially heterogeneous areas. The North American environment is modeled as 24 ecological regions, within each region contaminant fate is described using a 7 compartment multimedia fugacity model including a vertically segmented atmosphere, freshwater, freshwater sediment, soil, coastal water and vegetation compartments. Inter-regional transport of contaminants in the atmosphere, freshwater and coastal water is described usingmore » a database of hydrological and meteorological data compiled with Geographical Information Systems (GIS) techniques. Steady-state and dynamic solutions to the 168 mass balance equations that make up the linked model for North America are discussed, and an illustrative case study of toxaphene transport from the southern United States to the Great Lakes Basin is presented. Regionally segmented models such as BETR North America can provide a critical link between evaluative models of long-range transport potential and contaminant concentrations observed in remote regions. The continent-scale mass balance calculated by the model provides a sound basis for evaluating long-range transport potential of organic pollutants, and formulation of continent scale management and regulatory strategies for chemicals.« less

Assessing the risks of pesticides to threatened and endangered species using population modeling: A critical review and recommendations for future work.

PubMed

Forbes, Valery E; Galic, Nika; Schmolke, Amelie; Vavra, Janna; Pastorok, Rob; Thorbek, Pernille

2016-08-01

United States legislation requires the US Environmental Protection Agency to ensure that pesticide use does not cause unreasonable adverse effects on the environment, including species listed under the Endangered Species Act (ESA; hereafter referred to as listed species). Despite a long history of population models used in conservation biology and resource management and a 2013 report from the US National Research Council recommending their use, application of population models for pesticide risk assessments under the ESA has been minimal. The pertinent literature published from 2004 to 2014 was reviewed to explore the availability of population models and their frequency of use in listed species risk assessments. The models were categorized in terms of structure, taxonomic coverage, purpose, inputs and outputs, and whether the models included density dependence, stochasticity, or risk estimates, or were spatially explicit. Despite the widespread availability of models and an extensive literature documenting their use in other management contexts, only 2 of the approximately 400 studies reviewed used population models to assess the risks of pesticides to listed species. This result suggests that there is an untapped potential to adapt existing models for pesticide risk assessments under the ESA, but also that there are some challenges to do so for listed species. Key conclusions from the analysis are summarized, and priorities are recommended for future work to increase the usefulness of population models as tools for pesticide risk assessments. Environ Toxicol Chem 2016;35:1904-1913. © 2016 SETAC. © 2016 SETAC.

Adsorption of MCPA on goethite and humic acid-coated goethite.

PubMed

Iglesias, A; López, R; Gondar, D; Antelo, J; Fiol, S; Arce, F

2010-03-01

Anionic pesticides are adsorbed on the mineral oxide fraction of the soil surface but considerably less on the organic fraction, so that the presence of organic matter causes a decrease in the amount of pesticide adsorbed, and may affect the mechanism of adsorption. In the present study we investigated the adsorption of the weak acid pesticide MCPA on the surface of goethite and of humic acid-coated goethite, selected as models of the mineral oxide fraction and organic components present in soil systems. Adsorption of the anionic form of the pesticide on goethite fitted an S-type isotherm and the amount adsorbed increased as the ionic strength decreased and the pH of the medium decreased. Application of the charge distribution multi site complexation model (CD-MUSIC model) enabled interpretation of the results, which suggested the formation of inner and outer sphere complexes between the pesticide and the singly-coordinated surface sites of goethite. Less pesticide was adsorbed on the humic acid-coated goethite than on the bare goethite and the pattern fitted an L-type isotherm, which indicates a change in the mechanism of adsorption. Simplified calculations with the CD-MUSIC model enabled interpretation of the results, which suggested that the pesticide molecules form the same type of surface complexes as in the previous case. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Speed regulation of genetic cascades allows for evolvability in the body plan specification of insects

PubMed Central

Zhu, Xin; Rudolf, Heike; Healey, Lucas; François, Paul; Brown, Susan J.; Klingler, Martin; El-Sherif, Ezzat

2017-01-01

During the anterior−posterior fate specification of insects, anterior fates arise in a nonelongating tissue (called the “blastoderm”), and posterior fates arise in an elongating tissue (called the “germband”). However, insects differ widely in the extent to which anterior−posterior fates are specified in the blastoderm versus the germband. Here we present a model in which patterning in both the blastoderm and germband of the beetle Tribolium castaneum is based on the same flexible mechanism: a gradient that modulates the speed of a genetic cascade of gap genes, resulting in the induction of sequential kinematic waves of gap gene expression. The mechanism is flexible and capable of patterning both elongating and nonelongating tissues, and hence converting blastodermal to germband fates and vice versa. Using RNAi perturbations, we found that blastodermal fates could be shifted to the germband, and germband fates could be generated in a blastoderm-like morphology. We also suggest a molecular mechanism underlying our model, in which gradient levels regulate the switch between two enhancers: One enhancer is responsible for sequential gene activation, and the other is responsible for freezing temporal rhythms into spatial patterns. This model is consistent with findings in Drosophila melanogaster, where gap genes were found to be regulated by two nonredundant “shadow” enhancers. PMID:28973882

Geographical scenario uncertainty in generic fate and exposure factors of toxic pollutants for life-cycle impact assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huijbregts, Mark A.J.; Lundi, Sven; McKone, Thomas E.

In environmental life-cycle assessments (LCA), fate and exposure factors account for the general fate and exposure properties of chemicals under generic environmental conditions by means of 'evaluative' multi-media fate and exposure box models. To assess the effect of using different generic environmental conditions, fate and exposure factors of chemicals emitted under typical conditions of (1) Western Europe, (2) Australia and (3) the United States of America were compared with the multi-media fate and exposure box model USES-LCA. Comparing the results of the three evaluative environments, it was found that the uncertainty in fate and exposure factors for ecosystems and humansmore » due to choice of an evaluative environment, as represented by the ratio of the 97.5th and 50th percentile, is between a factor 2 and 10. Particularly, fate and exposure factors of emissions causing effects in fresh water ecosystems and effects on human health have relatively high uncertainty. This uncertainty i s mainly caused by the continental difference in the average soil erosion rate, the dimensions of the fresh water and agricultural soil compartment, and the fraction of drinking water coming from ground water.« less

Pesticides: an important but underused model for the environmental health sciences.

PubMed Central

Hodgson, E; Levi, P E

1996-01-01

Pesticides are high-volume, widely used, environmental chemicals and there is continuous debate concerning their possible role in many chronic human health effects. Because of their known structures, known rates of application, and the presence of a large occupationally exposed population, they are not only important in their own right but are ideal models for the effects of environmental chemicals on the population in general. For reasons that are not always clear, this potential has not been realized. These exposed populations represent an underused asset in the study of the human health effects of environmental contaminants. Chronic effects thought to involve pesticides include carcinogenesis, neurotoxicity, and reproductive and development effects. In this paper we attempt to summarize this concern and, relying to a large extent on studies in our own laboratory, to indicate the importance and present status of studies of the mammalian metabolism of pesticides and indicate the need for further use of this model. Aspects considered include the role of pesticides as substrates for xenobiotic-metabolizing enzymes such as cytochrome P450 and the flavin-containing monooxygenase and their role as inducers or inhibitors of metabolic enzymes. The interaction of pesticides with complex multienzyme pathways, the role of biological characteristics, particularly gender, in pesticide metabolism, and the special role of pesticides at portals of entry and in target tissues are also considered. PMID:8722114

Identification of pesticide varieties by detecting characteristics of Chlorella pyrenoidosa using Visible/Near infrared hyperspectral imaging and Raman microspectroscopy technology.

PubMed

Shao, Yongni; Li, Yuan; Jiang, Linjun; Pan, Jian; He, Yong; Dou, Xiaoming

2016-11-01

The main goal of this research is to examine the feasibility of applying Visible/Near-infrared hyperspectral imaging (Vis/NIR-HSI) and Raman microspectroscopy technology for non-destructive identification of pesticide varieties (glyphosate and butachlor). Both mentioned technologies were explored to investigate how internal elements or characteristics of Chlorella pyrenoidosa change when pesticides are applied, and in the meantime, to identify varieties of the pesticides during this procedure. Successive projections algorithm (SPA) was introduced to our study to identify seven most effective wavelengths. With those wavelengths suggested by SPA, a model of the linear discriminant analysis (LDA) was established to classify the pesticide varieties, and the correct classification rate of the SPA-LDA model reached as high as 100%. For the Raman technique, a few partial least squares discriminant analysis models were established with different preprocessing methods from which we also identified one processing approach that achieved the most optimal result. The sensitive wavelengths (SWs) which are related to algae's pigment were chosen, and a model of LDA was established with the correct identification reached a high level of 90.0%. The results showed that both Vis/NIR-HSI and Raman microspectroscopy techniques are capable to identify pesticide varieties in an indirect but effective way, and SPA is an effective wavelength extracting method. The SWs corresponding to microalgae pigments, which were influenced by pesticides, could also help to characterize different pesticide varieties and benefit the variety identification. Copyright © 2016 Elsevier Ltd. All rights reserved.

Spatially distributed modelling of pesticide leaching at European scale with the PyCatch modelling framework

NASA Astrophysics Data System (ADS)

Schmitz, Oliver; van der Perk, Marcel; Karssenberg, Derek; Häring, Tim; Jene, Bernhard

2017-04-01

The modelling of pesticide transport through the soil and estimating its leaching to groundwater is essential for an appropriate environmental risk assessment. Pesticide leaching models commonly used in regulatory processes often lack the capability of providing a comprehensive spatial view, as they are implemented as non-spatial point models or only use a few combinations of representative soils to simulate specific plots. Furthermore, their handling of spatial input and output data and interaction with available Geographical Information Systems tools is limited. Therefore, executing several scenarios simulating and assessing the potential leaching on national or continental scale at high resolution is rather inefficient and prohibits the straightforward identification of areas prone to leaching. We present a new pesticide leaching model component of the PyCatch framework developed in PCRaster Python, an environmental modelling framework tailored to the development of spatio-temporal models (http://www.pcraster.eu). To ensure a feasible computational runtime of large scale models, we implemented an elementary field capacity approach to model soil water. Currently implemented processes are evapotranspiration, advection, dispersion, sorption, degradation and metabolite transformation. Not yet implemented relevant additional processes such as surface runoff, snowmelt, erosion or other lateral flows can be integrated with components already implemented in PyCatch. A preliminary version of the model executes a 20-year simulation of soil water processes for Germany (20 soil layers, 1 km2 spatial resolution, and daily timestep) within half a day using a single CPU. A comparison of the soil moisture and outflow obtained from the PCRaster implementation and PELMO, a commonly used pesticide leaching model, resulted in an R2 of 0.98 for the FOCUS Hamburg scenario. We will further discuss the validation of the pesticide transport processes and show case studies applied to European countries.

Breakthrough dynamics of s-metolachlor metabolites in drinking water wells: Transport pathways and time to trend reversal

NASA Astrophysics Data System (ADS)

Farlin, Julien; Gallé, Tom; Bayerle, Michael; Pittois, Denis; Köppchen, Stephan; Krause, Martina; Hofmann, Diana

2018-06-01

We present the results of a two years study on the contamination of the Luxembourg Sandstone aquifer by metolachlor-ESA and metolachlor-OXA, two major transformation products of s-metolachlor. The aim of the study was twofold: (i) assess whether elevated concentrations of both transformation products (up to 1000 ng/l) were due to fast flow breakthough events of short duration or the signs of a contamination of the entire aquifer and (ii) estimate the time to trend reversal once the parent compound was withdrawn from the market. These two questions were addressed by a combined use of groundwater monitoring, laboratory experiments and numerical simulations of the fate of the degradation products in the subsurface. Twelve springs were sampled weekly over an eighteen month period, and the degradation rates of both the parent compound and its transformation products were measured on a representative soil in the laboratory using a radiolabeled precursor. Modelling with the numeric code PEARL simulating pesticide fate in soil coupled to a simple transfer function model for the aquifer compartment, and calibrated from the field and laboratory data, predicts a significant damping by the aquifer of the peaks of concentration of both metolachlor-ESA and -OXA leached from the soil. The time to trend reversal following the ban of s-metolachlor in spring protection zones should be observed before the end of the decade, while the return of contaminant concentrations below the drinking water limit of 100 ng/l however is expected to last up to twelve years. The calculated contribution to total water discharge of the fast-flow component from cropland and short-circuiting the aquifer was small in most springs (median of 1.2%), but sufficient to cause additional peaks of concentration of several hundred nanograms per litre in spring water. These peaks are superimposed on the more steady contamination sustained by the base flow, and should cease immediately once application of the parent compound stops.

[Analysis on influential factors of Chinese medicinal herb growers' willingness to use green pesticides: evidence on Panax notoginseng production areas in Wenshan, Yunnan province].

PubMed

Qian, Yun-Xu; Yang, Yue; Zhao, Wei; Cui, Xiu-Ming; Bi, Kai-Shun

2013-10-01

The purpose of the article is to apply a binary logistic model to analyze the major factors, which influence Chinese medicinal herb growers' willingness to use green pesticides by using survey data collected in Wenshan, Yunnan Province. The results indicate that, output per capita, average pesticide cost per mu, cognition of pesticide residues, expectations on Panax notoginseng prices, cognition of pesticides' effect of pests control, cognition of P. notoginseng prices of low pesticide residues have a significant influence on growers' willingness to use green pesticides. According to the analysis above, some proposals for enhancing Chinese medicinal herb growers' willingness to use green pesticides are put forward, such as, moving toward the intensive planting systems, fetching down the pieces of green pesticides, emphasizing and propagating the advantages of green pesticides, keeping the prices of Chinese medicinal herb running at steady rates.

Estimating Pesticide Effects on Fecundity Rates of Wild Birds Using Current Laboratory Reproduction Tests

EPA Science Inventory

The manuscript reviews the issues concerning the use of results on pesticide effects from laboratory avian reproduction tests for estimating potential impacts of pesticides on fecundity rates in avian population models.

The Drosophila vesicular monoamine transporter reduces pesticide-induced loss of dopaminergic neurons

PubMed Central

Lawal, Hakeem O.; Chang, Hui-Yun; Terrell, Ashley N.; Brooks, Elizabeth S.; Pulido, Dianne; Simon, Anne F.; Krantz, David E.

2010-01-01

Dopamine is cytotoxic and may play a role in the development of Parkinson’s disease. However, its interaction with environmental risk factors such as pesticides remains poorly understood. The vesicular monoamine transporter (VMAT) regulates intracellular dopamine content, and we have tested the neuroprotective effects of VMAT in vivo using the model organism Drosophila melanogaster. We find that Drosophila VMAT (dVMAT) mutants contain fewer dopaminergic neurons than wild type, consistent with a developmental effect, and that dopaminergic cell loss in the mutant is exacerbated by the pesticides rotenone and paraquat. Over-expression of DVMAT protein does not increase the survival of animals exposed to rotenone, but blocks the loss of dopaminergic neurons caused by this pesticide. These results are the first to demonstrate an interaction between a VMAT and pesticides in vivo, and provide an important model to investigate the mechanisms by which pesticides and cellular DA may interact to kill dopaminergic cells. PMID:20472063

Job Demands & Pesticide Exposure among Immigrant Latino Farmworkers

PubMed Central

Grzywacz, Joseph G.; Quandt, Sara A.; Vallejos, Quirina M.; Whalley, Lara E.; Chen, Haiying; Isom, Scott; Barr, Dana B.; Arcury, Thomas A.

2010-01-01

The goal of this study was to understand the potential threat of job stressors to farmworker health. To accomplish this goal we studied pesticide exposure, an issue with immediate and long-term health consequences, and predictions from the demands-control model of occupational stress. Longitudinal, self-report data and urine samples were collected at monthly intervals from a cohort of Latino farmworkers (N=287) during the 2007 agricultural season. The primary hypothesis was that greater exposure to psychological demands, physical exertion, and hazardous work conditions are associated with greater odds of detecting DAP urinary pesticide metabolites, biomarkers indicating exposure to pesticides. Contrary to this hypothesis, results indicated that none of the elements of the Demands-Control model were independently associated with detection of DAP urinary pesticide metabolites. However, analyses produced several interaction effects, including evidence that high levels of control may buffer the effects of physical job demands on detection of DAP urinary pesticide metabolites. PMID:20604632

Behavior of Multiclass Pesticide Residue Concentrations during the Transformation from Rose Petals to Rose Absolute.

PubMed

Tascone, Oriane; Fillâtre, Yoann; Roy, Céline; Meierhenrich, Uwe J

2015-05-27

This study investigates the concentrations of 54 multiclass pesticides during the transformation processes from rose petal to concrete and absolute using roses spiked with pesticides as a model. The concentrations of the pesticides were followed during the process of transforming the spiked rose flowers from an organic field into concrete and then into absolute. The rose flowers, the concrete, and the absolute, as well as their transformation intermediates, were analyzed for pesticide content using gas chromatography/tandem mass spectrometry. We observed that all the pesticides were extracted and concentrated in the absolute, with the exception of three molecules: fenthion, fenamiphos, and phorate. Typical pesticides were found to be concentrated by a factor of 100-300 from the rose flowers to the rose absolute. The observed effect of pesticide enrichment was also studied in roses and their extracts from four classically phytosanitary treated fields. Seventeen pesticides were detected in at least one of the extracts. Like the case for the spiked samples in our model, the pesticides present in the rose flowers from Turkey were concentrated in the absolute. Two pesticides, methidathion and chlorpyrifos, were quantified in the rose flowers at approximately 0.01 and 0.01-0.05 mg kg(-1), respectively, depending on the treated field. The concentrations determined for the corresponding rose absolutes were 4.7 mg kg(-1) for methidathion and 0.65-27.25 mg kg(-1) for chlorpyrifos.

Pesticides on residential outdoor surfaces: environmental impacts and aquatic toxicity.

PubMed

Jiang, Weiying; Luo, Yuzhou; Conkle, Jeremy L; Li, Juying; Gan, Jay

2016-07-01

Pesticides are routinely applied to residential impervious outdoor surfaces for structural pest control. This residential usage has been linked to the occurrence of toxic levels of pesticides in urban water bodies. It is believed that run-off water transports particles that have sorbed hydrophobic pesticides. However, concentrations of particle-bound pesticides have not been directly measured on impervious surfaces, and the role of these particles as a source of contamination is unknown. Pesticides were detected in 99.4% of samples, with >75% of samples containing at least five pesticides. Assuming all particles were transferred with run-off, the run-off amount of pesticide during each rainfall would be >5 mg. We also used the US EPA Storm Water Management Model and estimated that 43 and 65% of the pesticides would be washed off during two rainfall events, with run-off concentrations ranging from 10.0 to 54.6 ng L(-1) and from 13.3 to 109.1 ng L(-1) respectively. The model-predicted pesticide run-off concentrations were similar to the levels monitored in urban run-off and sediments. Most (78%) particle samples contained aggregate toxicities above the Hyalella azteca LC50 . The results suggest that loose particles on residential impervious surfaces are not only carriers but also an important source of hydrophobic pesticides in urban run-off and contribute to downstream aquatic toxicities. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Integration of transport concepts for risk assessment of pesticide erosion.

PubMed

Yang, Xiaomei; Van Der Zee, Sjoerd E A T M; Gai, Lingtong; Wesseling, Jan G; Ritsema, Coen J; Geissen, Violette

2016-05-01

Environmental contamination by agrochemicals has been a large problem for decades. Pesticides are transported in runoff and remain attached to eroded soil particles, posing a risk to water and soil quality and human health. We have developed a parsimonious integrative model of pesticide displacement by runoff and erosion that explicitly accounts for water infiltration, erosion, runoff, and pesticide transport and degradation in soil. The conceptual framework was based on broadly accepted assumptions such as the convection-dispersion equation and lognormal distributions of soil properties associated with transport, sorption, degradation, and erosion. To illustrate the concept, a few assumptions are made with regard to runoff in relatively flat agricultural fields: dispersion is ignored and erosion is modelled by a functional relationship. A sensitivity analysis indicated that the total mass of pesticide associated with soil eroded by water scouring increased with slope, rain intensity, and water field capacity of the soil. The mass of transported pesticide decreased as the micro-topography of the soil surface became more distinct. The timing of pesticide spraying and rate of degradation before erosion negatively affected the total amount of transported pesticide. The mechanisms involved in pesticide displacement, such as runoff, infiltration, soil erosion, and pesticide transport and decay in the topsoil, were all explicitly accounted for, so the mathematical complexity of their description can be high, depending on the situation. Copyright © 2016 Elsevier B.V. All rights reserved.

NEXT GENERATION MULTIMEDIA/MULTIPATHWAY EXPOSURE MODELING

EPA Science Inventory

The Stochastic Human Exposure and Dose Simulation model for pesticides (SHEDS-Pesticides) supports the efforts of EPA to better understand human exposures and doses to multimedia, multipathway pollutants. It is a physically-based, probabilistic computer model that predicts, for u...

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

PubMed

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.

A set of scientific issues being considered by the Environmental Protection Agency regarding: pesticide exposure modeling and climate change. SAP Minutes No. 2011-01. USEPA FIFRA Scientific Advisory Panel

USDA-ARS?s Scientific Manuscript database

The USEPA Office of Pesticide Programs (OPP) reviewed most of its human and ecological exposure assessment models for conventional pesticides to evaluate which inputs and parameters may be affected by changing climate conditions. To illustrate the approach used for considering potential effects of c...

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

USDA-ARS?s Scientific Manuscript database

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...

Walking the California County Lines with Pesticides on the ...

EPA Pesticide Factsheets

California has numerous aquatic threatened and endangered species and there is evidence that these species may be affected by non-target pesticide runoff. Modeling can play an important role in assessing the impact of pesticides but it requires complete data on pesticide use, monitoring data, and complex issues with land use. Using two small urban land use areas in Folsom and Roseville, California, we were able to overcome these issues using monitoring data from the California Department of Pesticide Regulation with monthly county use data from the California Pesticide Use database, and aerial photography for land use characterization. Using the U.S. Environmental Protection Agency (US EPA) Pesticide Water Calculator model, we successfully reproduced the overall magnitude of pyrethroids detected, frequency of extreme concentrations, and mean and median concentrations. This was a first step in estimating the proportion and location of pesticide contamination from urban areas in the Central Valley of California that may affect threatened and endangered fish. Validation was accomplished by adjacent watersheds, while performance was evaluated statistically and graphically. From this work, we recommend a joint US EPA/State of California citizen-science initiative involving homeowners with watershed-based tracking of their pesticide use; exploration of the use of homeowner/storeowner anecdotal information; and development of a Smart Phone App to enable interested par

A Quantitative Structure Activity Relationship for acute oral toxicity of pesticides on rats: Validation, domain of application and prediction.

PubMed

Hamadache, Mabrouk; Benkortbi, Othmane; Hanini, Salah; Amrane, Abdeltif; Khaouane, Latifa; Si Moussa, Cherif

2016-02-13

Quantitative Structure Activity Relationship (QSAR) models are expected to play an important role in the risk assessment of chemicals on humans and the environment. In this study, we developed a validated QSAR model to predict acute oral toxicity of 329 pesticides to rats because a few QSAR models have been devoted to predict the Lethal Dose 50 (LD50) of pesticides on rats. This QSAR model is based on 17 molecular descriptors, and is robust, externally predictive and characterized by a good applicability domain. The best results were obtained with a 17/9/1 Artificial Neural Network model trained with the Quasi Newton back propagation (BFGS) algorithm. The prediction accuracy for the external validation set was estimated by the Q(2)ext and the root mean square error (RMS) which are equal to 0.948 and 0.201, respectively. 98.6% of external validation set is correctly predicted and the present model proved to be superior to models previously published. Accordingly, the model developed in this study provides excellent predictions and can be used to predict the acute oral toxicity of pesticides, particularly for those that have not been tested as well as new pesticides. Copyright © 2015 Elsevier B.V. All rights reserved.

Modelling the fate of organic micropollutants in stormwater ponds.

PubMed

Vezzaro, Luca; Eriksson, Eva; Ledin, Anna; Mikkelsen, Peter S

2011-06-01

Urban water managers need to estimate the potential removal of organic micropollutants (MP) in stormwater treatment systems to support MP pollution control strategies. This study documents how the potential removal of organic MP in stormwater treatment systems can be quantified by using multimedia models. The fate of four different MP in a stormwater retention pond was simulated by applying two steady-state multimedia fate models (EPI Suite and SimpleBox) commonly applied in chemical risk assessment and a dynamic multimedia fate model (Stormwater Treatment Unit Model for Micro Pollutants--STUMP). 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 substance inherent properties to calculate MP fate but differ in their ability to represent the small physical scale and high temporal variability of stormwater treatment systems. Therefore the three models generate different results. A Global Sensitivity Analysis (GSA) highlighted that settling/resuspension of particulate matter was the most sensitive process for the dynamic model. The uncertainty of the estimated MP fluxes can be reduced by calibrating the dynamic model against total suspended solids data. This reduction in uncertainty was more significant for the substances with strong tendency to sorb, i.e. glyphosate and pyrene and less significant for substances with a smaller tendency to sorb, i.e. IPBC and benzene. The results provide support to the elaboration of MP pollution control strategies by limiting the need for extensive and complex monitoring campaigns targeting the wide range of specific organic MP found in stormwater runoff. Copyright © 2011 Elsevier B.V. All rights reserved.

Occurrence and Environmental Effects of Boscalid and Other Fungicides in Three Targeted Use Areas in the United States

NASA Astrophysics Data System (ADS)

Reilly, T. J.; Smalling, K. L.; Wilson, E. R.

2011-12-01

Fungicides are typically used to control the outbreak of persistent, historically significant plant diseases like late blight (caused by Phytophthora infestans and responsible for the Irish Potato famine of 1846) and newer plant diseases like Asian Soy Rust, both of which are potentially devastating if not controlled. Of the more than 67,000 pesticide products currently registered for use in the United States, over 3,600 are used to combat fungal diseases. Although they are widely used, relatively little is known about the fate and potential secondary effects of fungicides in the aquatic environment. Even less is known about the fate and environmental occurrence of recently registered fungicides including boscalid, which was first registered for use in the US in 2003. Unlike most other pesticides, multiple fungicides are typically applied as a prophylactic crop protectant upwards of ten times per season (depending upon conditions and crop type), but at lower application rates than herbicides or insecticides. This difference in usage increases the likelihood of chronic exposure of aquatic ecosystems to low concentrations of fungicides. Using a newly developed analytical method, the U.S. Geological Survey measured 33 fungicides in surface water and shallow groundwater in three geographic areas of intense fungicide use across the US. Sampling sites were selected near or within farms using prophylactic fungicides at rates and types typical of the crop type and their geographic location. At least one fungicide was detected in 75% of the surface waters (n=60) and 58% of the groundwater (n=12) samples. Twelve fungicides were detected in surface- and groundwater including boscalid (72%), azoxystrobin (51%), pyraclostrobin (40%), chlorothalonil (38%) and pyrimethanil (28%). Boscalid was the most frequently detected pesticide and has not been previously documented in the aquatic environment. In this study, an average of 44% of the pesticide concentration in a water sample was derived from a mixture of fungicides. Ongoing studies are also evaluating the occurrence of fungicides in aquatic insect larvae and the effects of fungicides on the obligate endosymbiont fungi (Trichomycetes) which reside in their guts. Surface water samples and larval hosts of gut fungi were collected from impaired and reference sites between April and December 2010 in southwestern Idaho, USA. Several fungicides (including azoxystrobin, boscalid and pyraclostrobin) were detected in black fly larvae collected from streams adjacent to agricultural fields where fungicides were being applied throughout the growing season. Hosts from control sites contained gut fungi with higher density, diversity and spore production, while those collected from the two impacted sites typically had lower diversity and fecundity (spore production) of native gut fungi. This study provides one of the first multi-regional assessments of the environmental occurrence of fungicides in the US and indicates that fungicides directly affect the non-target fungal communities commonly found in the guts of stream invertebrates.

The impact of pesticides on oxidative stress level in human organism and their activity as an endocrine disruptor.

PubMed

Jabłońska-Trypuć, Agata; Wołejko, Elżbieta; Wydro, Urszula; Butarewicz, Andrzej

2017-07-03

Pesticides cause serious environmental and health problems both to humans and animals. The aim of this review is to discuss selected herbicides and fungicides regarding their mode of action and their influence on basic oxidative stress parameters and endocrine disruption properties tested in selected cell cultures in vitro. Because of numerous difficulties which animal studies are subject to, cell cultures are an excellent experimental model reflecting human exposure to different pesticides through all relevant routes. This experimental model can be used to monitor aggregate and cumulative pesticide exposures.

U.S. Geological Survey Science at the Intersection of Health and Environment

NASA Astrophysics Data System (ADS)

Kimball, S. M.; Plumlee, G. S.

2016-12-01

People worldwide worry about how their environment affects their health, and expect scientists to help address these concerns. The OneHealth concept recognizes the crucial linkages between environment, human health, and health of other organisms. Many US Geological Survey science activities directly examine or help inform how the Earth and the environment influence toxicological and infectious diseases. Key is our ability to bring to bear a collective expertise in environmental processes, geology, hydrology, hazards, microbiology, analytical chemistry, ecosystems, energy/mineral resources, geospatial technologies, and other disciplines. Our science examines sources, environmental transport and fate, biological effects, and human exposure pathways of many microbial (e.g. bacteria, protozoans, viruses, fungi), inorganic (e.g. asbestos, arsenic, lead, mercury) and organic (e.g. algal toxins, pesticides, pharmaceuticals) contaminants from geologic, anthropogenic, and disaster sources. We develop new laboratory, experimental, and field methods to analyze, model, and map contaminants, to determine their baseline and natural background levels, and to measure their biological effects. We examine the origins, environmental persistence, wildlife effects, and potential for transmission to humans of pathogens that cause zoonotic or vector-borne diseases (e.g., avian influenza or West Nile virus). Collaborations with human health scientists from many organizations are essential. For example, our work with epidemiologists and toxicologists helps understand the exposure pathways and roles of geologically sourced toxicants such as arsenic (via drinking water) and asbestos (via dusts) in cancer. Work with pulmonologists and pathologists helps clarify the sources and fate of inhaled mineral particles in lungs. Wildlife health scientists help human health scientists assess animals as sentinels of human disease. Such transdisciplinary science is essential at the intersection of health and environment.

MODELING OF MACROSCALE AGRICULTURAL ELEMENTS IN PESTICIDE EXPOSURE

EPA Science Inventory

Yuma County, Arizona, is the site of year around agriculture. To understand the role of agricultural pesticide exposures experienced by children, urinary metabolite concentrations were compared with agricultural use of pesticides. The urinary metabolite and household data wer...

Rhinitis Associated with Pesticide Exposure among Commercial Pesticide Applicators in the Agricultural Health Study

PubMed Central

Slager, Rebecca E.; Poole, Jill A.; LeVan, Tricia D.; Sandler, Dale P.; Alavanja, Michael C. R.; Hoppin, Jane A.

2010-01-01

Objectives Rhinitis is common, but the risk factors are not well described. To investigate the association between current rhinitis and pesticide use, we used data from 2,245 Iowa commercial pesticide applicators in the Agricultural Health Study. Methods Using logistic regression models adjusted for age, education, and growing up on a farm, we evaluated the association between current rhinitis and 34 pesticides used in the past year. Results Seventy-four percent of commercial pesticide applicators reported at least one episode of rhinitis in the past year (current rhinitis). Five pesticides used in the past year were significantly positively associated with current rhinitis: the herbicides 2,4-D, glyphosate and petroleum oil, the insecticide diazinon and the fungicide benomyl. The association for 2,4-D and glyphosate was limited to individuals who used both in the past year (Odds Ratio = 1.42, 95% Confidence Interval: 1.14, 1.77). Both petroleum oil and diazinon showed consistent evidence of an association with rhinitis, based on both current use and exposure-response models. We saw no evidence of confounding by common agricultural rhinitis triggers such as handling grain or hay. Conclusions Exposure to pesticides may increase the risk of rhinitis. PMID:19289390

Noncanonical Wnt5a-Ca(2+) -NFAT signaling axis in pesticide induced bone marrow aplasia mouse model: A study to explore the novel mechanism of pesticide toxicity.

PubMed

Chattopadhyay, Sukalpa; Chatterjee, Ritam; Law, Sujata

2016-10-01

According to case-control studies, long-term pesticide exposure can cause bone marrow aplasia like hematopoietic degenerative disease leading to impaired hematopoiesis and increased risk of aplastic anemia in human subjects. However, the exact mechanism of pesticide mediated hematotoxicity still remains elusive. In this study, we investigated the role of noncanonical Wnt signaling pathway, a crucial regulator of adult hematopoiesis, in pesticide induced bone marrow aplasia mouse model. Aplasia mouse model was developed following inhalation and dermal exposure of 5% aqueous mixture of common agriculturally used pesticides for 6 h/day for 5 days a week up to 90 days. After that, blood hemogram, marrow smear, cellularity, scanning electron microscopy, extramedullary hematopoiesis and flowcytometric expression analysis of noncanonical Wnt signaling components, such as Wnt 5a, fzd5, NFAT, IFN-γ, intracellular Ca(2+) level were evaluated in the bone marrow hematopoietic stem/progenitor compartment of the control and pesticide induced aplasia groups of animals. Results showed that pesticide exposed mice were anemic with peripheral blood pancytopenia, hypocellular degenerative marrow, and extramedullary hematopoiesis in the spleen. Upon pesticide exposure, Wnt 5a expression was severely downregulated with a decline in intracellular Ca(2+) level. Moreover, downstream of Wnt5a, we observed sharp downregulation of NFATc2 transcription factor expression, the major target of pesticide toxicity and its target molecule IFN-γ. Taken together, our result suggests that deregulation of Wnt5a-Ca(2+) -NFAT signaling axis in the hematopoietic stem/progenitor compartment plays a crucial role behind the pathogenesis of pesticide mediated bone marrow aplasia by limiting primitive hematopoietic stem cells' ability to maintain hematopoietic homeostasis and reconstitution mechanism in vivo during xenobiotic stress leading to ineffective hematopoiesis and evolution of bone marrow aplasia. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1163-1175, 2016. © 2015 Wiley Periodicals, Inc.

MODELING ENVIRONMENTAL EXPOSURES TO PARTICULATE MATTER AND PESTICIDES

EPA Science Inventory

This presentation describes initial results from on-going research at EPA on modeling human exposures to particulate matter and residential pesticides. A first generation probabilistic population exposure model for Particulate Matter (PM), specifically for predicting PM1o and P...

Linear and nonlinear models for predicting fish bioconcentration factors for pesticides.

PubMed

Yuan, Jintao; Xie, Chun; Zhang, Ting; Sun, Jinfang; Yuan, Xuejie; Yu, Shuling; Zhang, Yingbiao; Cao, Yunyuan; Yu, Xingchen; Yang, Xuan; Yao, Wu

2016-08-01

This work is devoted to the applications of the multiple linear regression (MLR), multilayer perceptron neural network (MLP NN) and projection pursuit regression (PPR) to quantitative structure-property relationship analysis of bioconcentration factors (BCFs) of pesticides tested on Bluegill (Lepomis macrochirus). Molecular descriptors of a total of 107 pesticides were calculated with the DRAGON Software and selected by inverse enhanced replacement method. Based on the selected DRAGON descriptors, a linear model was built by MLR, nonlinear models were developed using MLP NN and PPR. The robustness of the obtained models was assessed by cross-validation and external validation using test set. Outliers were also examined and deleted to improve predictive power. Comparative results revealed that PPR achieved the most accurate predictions. This study offers useful models and information for BCF prediction, risk assessment, and pesticide formulation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Herbicide concentrations in the Mississippi River Basin - The importance of chloroacetanilide herbicide degradates

USGS Publications Warehouse

Rebich, R.A.; Coupe, R.H.; Thurman, E.M.

2004-01-01

The proportion of chloroacetanilide herbicide degradates, specifically the ethane sulfonic (ESA) and oxanilic (OA) acids, averaged 70% of the total herbicide concentration in samples from the Upper Mississippi River. In samples from the Missouri River and the Ohio River, the proportion of chloroacetanilide degradates in the total herbicide concentration was much less, 24% and 41%, respectively. The amount of tile drainage throughout the Mississippi River Basin appeared to be related to the occurrence and distribution of chloroacetanilide degradates in water samples. Pesticide concentrations in streams of the Mississippi River Basin have been well characterized. However, recent research demonstrates that in order to more fully understand the fate and transport of pesticides, the major pesticide degradates need to be included in the analysis. From March 1999 through May 2001, water samples from four major junctures of the Mississippi River Basin were collected and analyzed for a suite of herbicides and their degradate compounds. Each sampling site was selected to represent a major part of the Mississippi River: upper and lower Mississippi, Missouri and Ohio Rivers. Each basin has unique landscape variables, geology, hydrology, precipitation, and land use, which is reflected in the pesticide content at the most downstream sample site near the mouth of the Mississippi River. Atrazine was the most frequently detected herbicide (detected in 97% of the samples), followed by metolachlor (60%), and acetochlor (31%). The most frequently detected degradates were metolachlor ESA (69%), followed by deethylatrazine (62%), metolachlor OA (37%), and alachlor ESA (37%). Metolachlor ESA was detected more frequently than its parent compound (69 vs. 60%), as was alachlor ESA (37 vs. 9%). After an improvement was made in the analytical method, metolachlor ESA was detected in every sample, metolachlor OA in 89% of the samples, alachlor ESA in 84%, acetochlor ESA in 71%, and acetochlor OA in 66%. ?? 2003 Elsevier B.V. All rights reserved.

Occurrence of 1,1'-dimethyl-4,4'-bipyridinium (Paraquat) in irrigated soil of the Lake Chad Basin, Niger.

PubMed

Crampon, Marc; Copard, Yoann; Favreau, Guillaume; Raux, Julie; Merlet-Machour, Nadine; Le Coz, Mathieu; Ibrahim, Maïmouna; Peulon-Agasse, Valérie; Portet-Koltalo, Florence

2014-09-01

Increased use of agrochemical products to improve yields for irrigated crops in sub-Saharan Africa has been accompanied by a significant increase in the risk of environmental contamination. Detailed examples of the fate of pesticides after initial spreading on crop fields are scarce in tropical regions, where safe practices and related health risks are poorly understood by smallholder farmers. In the semi-arid environment of the Lake Chad Basin, SE Niger, both intrinsic properties of pesticides and extrinsic factors such as soil and climate helped to characterize processes leading to an accumulation of pesticides in soils. Analysis by HPLC-UV of a 6 m deep soil profile showed the presence of Paraquat at concentrations from 953 ± 102 μg kg(-1) to 3083 ± 175 μg kg(-1) at depths between 0.80 and 2.75 m below the land surface. Soil analysis revealed that up to approximately 15 % of the total soil matrix consists of smectites, a clay mineral capable of retaining cationic pesticides such as Paraquat, and a very low content of organic matter (<0.15 wt.% TOC). Paraquat could be stored and not bioavailable in a clayey barrier at approximately 2-m depth and therefore does not represent an immediate risk for populations or environment in this form. However, if the Paraquat application rate remains constant, the clayey barrier could reach a saturation limit within 150-200 years and 180-220 years if we consider a DT50 in soil of ~1,000 days (FAO). Consequently, it could lead to a deeper infiltration and so a pollution of groundwater. Such a scenario can represent a health risk for drinking water and for the Lake Chad, which is a major resource for this densely populated region of semi-arid Africa. Further analyses should focus on deeper layers and groundwater Paraquat contents to validate or invalidate the hypothesis of storage in this clay-rich layer.

SENSITIVE PARAMETER EVALUATION FOR A VADOSE ZONE FATE AND TRANSPORT MODEL

EPA Science Inventory

This report presents information pertaining to quantitative evaluation of the potential impact of selected parameters on output of vadose zone transport and fate models used to describe the behavior of hazardous chemicals in soil. The Vadose 2one Interactive Processes (VIP) model...

Bioremediation strategies for pesticide-contaminated sites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chaplin-Anhalt, J.A.; Anderson, T.A.; Perkovich, B.S.

1995-12-31

As the number of pesticide-contaminated sites at places such as agrochemical dealerships continues to grow there is an urgent need to find methods of remediation. Soils from two pesticide-contaminated sites, Alpha and Bravo, were analyzed using gas chromatography. The contaminants and their concentrations ({mu}g/g) were as follows: atrazine (0.1 to 24), metolachlor (2 to 121), trifluralin (1 to 244), and pendimethalin (5 to 334). A radiotracer study was conducted to determine the fate of a combined application of atrazine and metolachlor at a concentration of 50 {mu}g/g each. The mixture was applied to Alpha and Bravo nonvegetated soils and Kochiamore » scoparia rhizosphere soils. After 30 d incubation in Bravo soil, mineralization of metolachlor was minimal with less than 1% recovered as {sup 14}CO{sub 2}. Metolachlor degradation in the rhizosphere soil was greater than in nonvegetated soils with 56% and 100% of metolachlor remaining, respectively, after 30 d. Atrazine mineralization was as high as 62% of the applied {sup 14}C. Additional soil from Bravo was treated with 50 {mu}g/g of unlabeled atrazine. The soil was divided into three treatments and a control with three replicates each. Each treatment involved inoculation of 100 g of Bravo soil with 2 g from one of three soils determined in our laboratory to have enhanced atrazine degradative capabilities. Soils were incubated for 15 or 35 d. The soils will be analyzed by gas chromatography to determine which, if any, of the inoculants increase the degradation of atrazine.« less

Organic contaminants in western pond turtles in remote habitat in California.

PubMed

Meyer, Erik; Eskew, Evan A; Chibwe, Leah; Schrlau, Jill; Massey Simonich, Staci L; Todd, Brian D

2016-07-01

Remote aquatic ecosystems are exposed to an assortment of semivolatile organic compounds (SOCs) originating from current and historic uses, of local and global origin. Here, a representative suite of 57 current- and historic-use pesticides, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons were surveyed in the plasma of the western pond turtle (Emys marmorata) and their potential prey items and habitat. California study sites included Sequoia National Park, Whiskeytown National Recreation Area, and Six Rivers National Forest. Each was downstream of undeveloped watersheds and varied in distance from agricultural and urban pollution sources. SOCs were detected frequently in all sites with more found in turtle plasma and aquatic macroinvertebrates in the two sites closest to agricultural and urban sources. Summed PCBs were highest in Whiskeytown National Recreation Area turtle plasma (mean; 1.56 ng/g ww) compared to plasma from Sequoia National Park (0.16 ng/g ww; p = 0.002) and Six Rivers National Forest (0.07 ng/g ww; p = 0.001). While no current-use pesticides were detected in turtle plasma at any site, both current- and historic-use pesticides were found prominently in sediment and macroinvertebrates at the Sequoia National Park site, which is immediately downwind of Central Valley agriculture. SOC classes associated with urban and industrial pollution were found more often and at higher concentrations at Whiskeytown National Recreation Area. These findings demonstrate a range of SOC exposure in a turtle species with current and proposed conservation status and shed additional light on the fate of environmental contaminants in remote watersheds. Published by Elsevier Ltd.