Tiered Testing Approach for Whole-Sediment Toxicity Tests
A majority of recent data call-ins (DCIs) issued by the USEPA for pesticide registrants have included requirements for chronic sediment toxicity testing with midge as well as freshwater and marine amphipod species. Sediment toxicity testing triggers for either acute or chronic studies are currently based predominately on environmental fate data focused on compound-specific degradation and partitioning behavior. Biological data are only used to evaluate risk while determining if chronic sediment data are needed; however, acute sediment toxicity data are seldom available for such comparisons. While ecotoxicity data from water-only studies may be leveraged to estimate thresholds for benthic organisms based on sediment equilibrium partitioning theory; this approach may introduce substantial uncertainty into ecological risk assessment and is likely most effectively used as a lower level screening tool.
Jennifer K. Collins, Mark A. Cafarella. Tiered Testing Approach for Whole-Sediment Toxicity Tests. SETAC North America 35th Annual Meeting, Vancover, B.C. November 14, 2014.
PostersHome and Personal Care Products, Human Pharmaceuticals, Industrial and Specialty Chemicals2014
Tools for Probabilistic Environmental Exposure Assessment of “Down-The-Drain” Chemicals in The U.S.
Environmental exposure assessment of down-the-drain chemicals (home and personal care products, pharmaceuticals, etc.) is strongly dependent upon the in-stream dilution of receiving waters, which varies by geography and flow conditions. In this study, the iSTREEM® model (www.istreem.org, American Cleaning Institute) was utilized to delineate probabilistic distributions of practical dilution factors (flow-based as well as incorporating varying chemical biodegradation rates) in mean and low flow conditions, as well as the national distribution of per capita domestic wastewater production. The distributions yielded by this work can serve as a reference for probabilistic exposure assessments for down-the-drain chemicals in wastewater treatment plant (WWTP) mixing zones and at drinking water intakes in the conterminous U.S. In addition, an assessment of treatment processes based on the WWTP facilities within the iSTREEM model provided an assessment of the proportion of wastewater flow volume treated by various processes (activated sludge, lagoon, etc.). The ability to quantitatively evaluate waste water production, treatment, and dilution in a spatial context provides a practical and powerful tool for assessing exposure and risk of down-the-drain chemicals of various types.
Katherine E. Kapo, Kathleen McDonough, Tom Federle, Scott D. Dyer, Raghu Vamshi, Chris M. Holmes. Tools for Probabilistic Environmental Exposure Assessment of “Down-The-Drain” Chemicals in The U.S. SETAC North America 35th Annual Meeting, Vancover, B.C. November 14, 2014.
A Framework for Modeling Pyrethroid Transport to Surface Water Via Runoff/Erosion and Drift Using Local Scale Data at the NHD+ Catchment Scale
The Pyrethroid Working Group (PWG) has conducted a national probabilistic refinement of aquatic exposure estimates for agricultural pyrethroid uses. A spatial modeling framework was developed to perform probabilistic drift and runoff/erosion transport modeling for over 2.5 million NHD+ catchments covering the entire conterminous US , in order to capture the natural variability in weather, soils, cropping and other agronomic/environmental factors. Drift transport was modeled using information on crop proximity to individual stream reaches and deposition fractions based on AgDRIFT/RegDisp models. Crop location data used for proximity analysis and soil/crop associations were based on the USDA Cropland Data Layer (CDL) from 2008-2012. Chemical mass transported via runoff/erosion was estimated over 30 years for more than 375,000 unique soil/weather combinations and ten crops using PRZM modeling for a hypothetical representative pyrethroid. Other relevant landscape metrics (e.g., length of streams or number of ponds) or agronomic metrics (e.g., tillage practices) were also characterized at the NHD+ catchment level. The resulting spatio-temporal databases underpinned several different approaches for novel probabilistic exposure analyses of the pyrethroids. This framework takes advantage of automation opportunities within both ArcGIS and SQL Server in order to process massive amounts of spatial and temporal data in an efficient and robust manner. This poster will present the overall framework developed for the PWG, along with specifics on data sources, processing steps, and results.
Joshua Amos, Vivienne Sclater, Christopher Holmes, Paul Hendley, Russell Jones, Scott Jackson , Russell Underwood. A Framework for Modeling Pyrethroid Transport to Surface Water Via Runoff/Erosion and Drift Using Local Scale Data at the NHD+ Catchment Scale. SETAC North America 35th Annual Meeting, Vancover, B.C. November 14, 2014.
PostersHome and Personal Care Products2014
Accounting for Regional Differences in Socioeconomic and Environmental Variables to Enable a Global Exposure Assessment for Chemicals Used in HPC Products
The global use of a range of home and personal care (HPC) products increased between 232% and 750% from 1998 and 2013. This global trend is likely to continue for the foreseeable future, as growth in emerging markets in South America, Africa and Asia continues. Industry has a responsibility to assess the environmental safety of chemicals used in consumer goods in all markets, not only in regions where Regulations exist. We present an initiative to collect spatially explicit data sets in order to develop a global model to enable in-river concentrations of chemicals used in home and personal care products to be predicted. The model incorporates sub-national variability in HPC product use, geographically-linked socioeconomic data to account for a population’s ability to purchase certain products, water use and disposal data, information on sanitation practices and in river dilution factors from official census and other data sources. A novel exposure model, the Scenario Assembly Tool (ScenAT), was developed to predict environmental concentrations (PECs) of chemicals used in HPC products at multiple spatial scales across a country. In this study, we compare regional and country profiles of important variables that influence the exposure of home and personal care products (e.g. water use and sanitation practice, receiving water). We share socioeconomic and environmental databases that have been compiled to enable risk assessors to conduct robust assessment in developed and emerging markets. We explore the impact of these variables on emission estimates and PEC distributions in major regions across the globe and discuss regional differences. We use a case study to demonstrate how the model can be used to support screening level risk assessment decision-making.
Raghu Vamshi, Juliet Hodges, Christopher Holmes, Vivienne Sclater, Oliver Price, John Kilgallon, Todd Gouin. Accounting for Regional Differences in Socioeconomic and Environmental Variables to Enable a Global Exposure Assessment for Chemicals Used in HPC Products. SETAC North America 35th Annual Meeting, Vancover, B.C. November 14, 2014.
Moving Forward On NAS Panel Report Recommendations Using GIS And Geospatial Data For Endangered Species Risk Assessments
The National Academy of Sciences (NAS) report released last year, along with subsequent presentations by the USEPA, USFWS, and NMFS, highlighted the use of geospatial data and methods as part of the pesticide risk assessment for Threatened and Endangered (T&E) species. The geospatial proximity of potential pesticide use areas to T&E species locations is an important aspect in each of the three Steps outlined in the NAS report. This is especially important in Step 1, where spatial proximity screening can be used to remove species from concern, eliminating the need for consultation, so that resources and efforts can be focused on those species/geographies that can benefit from additional efforts. This presentation will describe the use of geospatial data within a Geographic Information System (GIS) as it applies to this process. Firstly in Step 1, authoritative spatial data on temporal crop locations were used to develop a spatial layer representing potential pesticide use sites. Secondly, the spatial definition and implementation of the action area is presented based on exposure modeling results. Following this, information on species location may require pre-processing or refinement within a GIS, as it may come from a variety of sources. Finally, a proximity analysis will be shown which incorporates the preceding information, along with resulting distances that can be used in the risk assessment. Subsequent spatial and temporal refinements at Step 2 and beyond will be discussed.
Nathan J. Snyder and Amy M. Ritter. Moving Forward on NAS Panel Report Recommendations Using a Stepwise Approach in Fate and Transport Modeling for Endangered Species Risk Assessments. SETAC North America 35th Annual Meeting, Vancover, B.C. November 14, 2014.
By: Chris Holmes, Josh Amos, Vivienne Sclater
Conference: SETAC North America 35th Annual Meeting
Date: Friday, November 14, 2014
Duration: 15 Minutes
Presenter: Chris Holmes
Papers & ReportsCrop Protection2014
Factors Affecting Residential Runoff Transport of Pyrethroids
Replicated runoff studies investigating the transport of pyrethroids applied to suburban residences were conducted at a full scale test facility in central California over two years. The first year of results showed losses from historic practices mainly from applications made to impervious surfaces (such as driveways or walls adjacent to driveways) as a result of runoff generated by simulated or natural rainfall. Revised application procedures according to new product labeling specifying spot applications to impervious surfaces reduced runoff losses of pyrethroids by a factor of 40 compared to historic practices. The second year of testing examined the effect of formulation on washoff from driveways or walls adjacent to driveways. Differences in runoff losses between five pairs of product formulations under field scale conditions were considerably less than in small scale laboratory experiments. Also in one pair, one formulation gave higher washoff in laboratory experiments and the other formulation gave higher washoff under field conditions. Therefore, laboratory studies assessing the effect of formulation on runoff losses may not always be predictive of behavior under actual use conditions so field studies remain important for understanding runoff losses from residential pesticide treatments.
“Describing the Behavior and Effects of Pesticides in Urban and Agricultural Setting, Chapter 2: Factors Affecting Residential Runoff Transport of Pyrethroids.” (Jones, R.L., Davidson, P.C., Harbourt, C.M. and Hendley, P.) American Chemical Society, 2014. Electronic Publication.
PostersAgriculture and Food, Crop Protection2014
Identification of the Sensitivity of Estimated Aquatic Exposure Concentrations from PRZM and AGRO-2014 Modeling to Variation in Chemical, Field Application, and Receiving Water Body Input Parameters for Synthetic Pyrethroid Agricultural Use Patterns
This analysis focused on individual parameters to identify variables having the greatest impact on predicted pyrethroid runoff and erosion mass loadings from the PRZM model as well as those expected to impact receiving water body concentrations predicted by the AGRO-2014 modeling system. The results show the sensitivity of a “base case” due to variation in individual parameters. A hypothetical pyrethroid (Hypothrin) was developed which was representative of the physicochemical characteristics, environmental fate profile, and crop use patterns of all foliar applied pyrethroids. The USEPA cotton (MS) and lettuce (CA) standard PRZM scenarios were used as the base case for simulating Hypothrin aquatic exposures in the standard pond. These two scenarios were chosen because they represent wetter (high erosion) and drier (lower erosion) conditions. This study showed that the PRZM and AGRO-2014 models were highly sensitive to numerous individual parameters related to the amount of chemical applied, to chemical field degradation, factors that greatly influence edge-of-field runoff/erosion flows, and to those related to pond geometry and water-sediment partitioning.
Dean Desmarteau, Amy Ritter, Paul Hendley. (1) Waterborne Environmental, Inc., Leesburg, VA 20175, United States, (2) Phasera Ltd., Bracknell, Berkshire RG12 2JJ, United Kingdom. ACS/IUPAC 2014.
Landscape-Level Refinements for Probabilistic Pyrethroid Exposure Assessments in Agricultural Environments
The Pyrethroid Working Group (PWG) has conducted a probabilistic refinement of aquatic exposure estimates for agricultural pyrethroid uses incorporating step-wise refinements to standard USEPA Tier II exposure modeling scenarios. Weather, soils, cropping and other environmental factors were summarized to over 2.5 million catchments in the USGS NHD+ dataset, and used to model the national range of crop-specific potential pyrethroid drift and runoff/erosion transport to surface water. Using over 375,000 PRZM runs incorporating local cropping, weather and soils data, along with NHD+ flowline specific drift estimates for each catchment, a matrix of 11 representative drift rates and 10 representative runoff/erosion PRZM runs was created for each crop of interest. This was used to develop a set of 110 scenarios, each representing a specific proportion of the distribution. Probabilities for each matrix bin were computed based on the actual catchment area represented by each combination of drift and runoff/erosion nationally. Each of the 110 scenarios was modeled by linking PRZM, VFSMOD and AGRO-2014 to produce 30 year distributions of annual maximum aquatic EECs. The combined set of annual maximum EEC values along with the weighting matrix, were used to generate a distribution of crop-specific EECs suitable for probabilistic risk characterization. This approach allowed other variables (e.g. the percentage of each crop treated with any pyrethroid insecticide) to be readily incorporated into the probabilistic assessment. Resulting potential exposure distributions for ten different crops were used in multiple pyrethroid risk assessments submitted to USEPA.
By: Chris Holmes, Paul Hendley, Josh Amos, Amy Ritter, Mark Cheplick, Dean Desmarteau, Russell Jones, Scott Jackson, Russell Underwood
Conference: SETAC North America 35th Annual Meeting
Date: Thursday, November 13, 2014
Duration: 15 Minutes
Presenter: Chris Holmes
Review of Pesticide Environmental Fate Parameters and Their Quantitative Relationship With Soil and Climate Conditions
Pesticide sorption and degradation in soil are two critical, interlinked and extensively studied processes for assessing a pesticide’s potential environmental mobility and persistence. There is a wealth of data on this in published literature. This presentation summarizes the results of a recent IUPAC research project (2010-018-2-600) focusing on quantitative relationships of the environmental fate processes of pesticide with broader soil properties, climate variables, and potential molecular structure-activity influencing their fate and behavior. The coupling relationship of degradation with sorption in soil and its implications for determining the bioavailability and biodegradability factors will be discussed. Calibration of the reviewed data with local environmental conditions is explored to improve fate parameter estimation. This may directly benefit data deficient regions with limited pesticide fate studies (e.g. tropical soils, and scientifically emerging regions in Africa, Asia and South America). Results are also expected to provide valuable information for the refinement of pesticide environmental exposure assessment models in general.
Wenlin Chen, William Koskinen, Annemieke Farenhorst, Volker Laabs, Amy Ritter, Rai Kookana, Aleksandar Sabljic, Robin Sur, Riaz Ahmad, Elizabeth Carazo, Jairo A. Guerrero D. Karina S.B. Miglioranza, Veronica Cesio, Junying Zhou. (1) Syngenta Crop Protection, LLC, Greensboro, NC, United States, (2) University of Minnesota, United States, (3) University of Manitoba, Canada, (4) BASF, Germany, (5) Waterborne Environmental, Inc, United States, (6) CSIRO Land and Water, Australia, (7) Institute Rudjer Boskovic, Croatia, (8) Bayer CropScience LP, United States, (9) Punjab Agricultural Research Board, Pakistan, (10) Universidad de Costa Rica, Costa Rica, (11) Universidad Nacional de Colombia, Colombia, (12) Universidad Nacional de Mar del Plata, Argentina, (13) Universidad de la República, Uruguay, (14) Nanjing Institute of Environmental Science, China
Refining Pyrethroid Aquatic Exposure Assessments By Incorporating Measured Landscape and Environmental Variability Using Probabilistic Approaches. III – Characterizing the Probability of Wind Speeds and Direction Across Multiple Insecticide Applications Within a Season
The Pyrethroid Working Group (PWG) is conducting a probabilistic refinement of aquatic exposure estimates for agricultural pyrethroid insecticide uses. This presentation will focus on potential aquatic ecological exposure from drift due to pyrethroid use on crops. Because many pyrethroid use patterns permit multiple aerial applications, using 16 meteorological stations nationally, PWG has investigated the likelihood of occurrence that the wind will be blowing towards the water body at or above 10 mph on every application day at all Tier II exposure scenario locations. Using hourly wind speed and direction data for SAMSON weather stations, an analysis was performed for early morning or early evening application hours for “n” applications occurring “m” days apart (as specified for a particular crop on pyrethroid labels) for a range of feasible start dates for 30 weather years. Additionally, the presentation examines the probabilistic distribution of annual loadings from aerial drift to the standard pond when the actual wind speed, temperature, humidity and wind direction on the day of application are considered (AgDRIFT® aerial Tier II) compared to annual loadings using AgDRIFT® aerial Tier I default values. These loadings were compared to EPA Tier II assumptions and also incorporated directly into some example AGRO-2014 model runs to compute estimated environmental concentrations (EECs). Inclusion of wind speed, direction and associated meteorological drift drivers significantly modified the estimated distribution of annual maximum EECs via significant decreases of most annual loadings.
Amy M Ritter, William Northcott, Paul Hendley, Megan L White. (1) Waterborne Environmental, Inc., Leesburg, VA 20175, United States, (2) Phasera Ltd., Bracknell, Berkshire RG12 2JJ, United Kingdom