Montpelier, VT, United States
Montpelier, VT, United States

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Whitfield Aslund M.,Intrinsik Environmental Sciences Inc. | Breton R.L.,Carleton University | Padilla L.,Stone Environmental | Winchell M.,Stone Environmental | And 5 more authors.
Environmental Toxicology and Chemistry | Year: 2017

A probabilistic risk assessment of the potential direct and indirect effects of acute dimethoate exposure to salmon populations of concern was conducted for 3 evolutionarily significant units (ESUs) of Pacific salmon in California. These ESUs were the Sacramento River winter-run chinook, the California Central Valley spring-run chinook, and the California Central Valley steelhead. Refined acute exposures were estimated using the Soil and Water Assessment Tool, a river basin–scale model developed to quantify the impact of land-management practices in large, complex watersheds. Both direct effects (i.e., inhibition of brain acetylcholinesterase activity) and indirect effects (i.e., altered availability of aquatic invertebrate prey) were assessed. Risk to salmon and their aquatic invertebrate prey items was determined to be de minimis. Therefore, dimethoate is not expected to have direct or indirect adverse effects on Pacific salmon in these 3 ESUs. Environ Toxicol Chem 2017;36:532–543. © 2016 SETAC. © 2016 SETAC


Winchell M.,Stone Environmental | Padilla L.,Stone Environmental | Jackson S.,BASF | Mitchell G.,FMC Corporation
ACS Symposium Series | Year: 2014

An urban residential pesticide exposure modeling approach using the Storm Water Management Model (SWMM) has been developed and validated in a high density residential watershed in southern California. The approach incorporates pyrethroid wash-off characteristics from pervious and impervious surfaces, neighborhood characteristics, and local pyrethroid application practices. This modeling approach was extended to the Southeast, South Central, Northwest, North Central, Northeast, and Mid-Atlantic US through parameterization of local use practices, along with local weather and irrigation characteristics. Application of the SWMM modeling approach to a broader population of regional conditions has provided aquatic exposure estimates important for developing a comprehensive higher tier ecological risk assessment for pyrethroids at the national scale. © 2014 American Chemical Society.


Winchell M.,Stone Environmental | Peranginangin N.,Syngenta | Estes T.,Stone Environmental | Padilla L.,Stone Environmental | And 2 more authors.
ACS Symposium Series | Year: 2014

The standard regulatory approach for predicting aquatic pesticide Expected Environmental Concentrations (EECs) in an ecological risk assessment is to use the PRZM/EXAMS model to simulate a ten hectare field draining into a one hectare pond. This approach assumes that 100% of the crop area draining into the pond is treated with the pesticide on a soil representative of the geographic region and crop. In reality, the characteristics of pond drainage areas vary widely over the geographic extent of interest for a typical exposure assessment. An approach that accounts for variability in soils, weather, percent cropped area, and pesticide use was developed to predict aquatic pesticide concentrations as part of an endangered species risk assessment. The approach used spatially explicit data and the PRZM/EXAMS model to predict a probability distribution of aquatic EECs reflective of the species habitat area and may be applied in exposure assessments required for other ecological risk assessments. © 2014 American Chemical Society.


Budreski K.,Stone Environmental | Richardson K.,Esri
Sea Technology | Year: 2010

Ecosystem-based management (EBM) is the study of all the complex interactions within an ecosystem. The atlas was developed by the New York Ocean and Great Lakes Ecosystem Conservation Council. The council, created in 2006, is chartered with protecting, restoring and enhancing New York's ocean and Great Lakes ecosystems while taking into account sustainable economic development and job creation. The portal provides a robust way for users to search all the data holdings in the atlas. Users of the portal can perform metadata searches by keyword, data type, data category, date modified and geographic location. Information for specific areas of interest can be easily found and compared in this manner. Many datasets are from organizations that had never widely distributed geospatial data before. Data providers have several avenues to easily publish data using the portal.


Estes T.L.,Stone Environmental | Pai N.,Stone Environmental | Winchell M.F.,Stone Environmental
Pest Management Science | Year: 2015

BACKGROUND: 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. RESULTS: 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. CONCLUSION: 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 1000Lkg-1 and no simulated hydrolysis, PRZM-GW overpredicted, often by greater than 100ppb. © 2015 Society of Chemical Industry.


PubMed | Stone Environmental and Syngenta
Type: Journal Article | Journal: Integrated environmental assessment and management | Year: 2016

A crop footprint refers to the estimated spatial extent of growing areas for a specific crop, and is commonly used to represent the potential use site footprint for a pesticide labeled for use on that crop. A methodology for developing probabilistic crop footprints to estimate the likelihood of pesticide use and the potential co-occurrence of pesticide use and listed species locations was tested at the national scale and compared to alternative methods. The probabilistic aspect of the approach accounts for annual crop rotations and the uncertainty in remotely sensed crop and land cover data sets. The crop footprints used historically are derived exclusively from the National Land Cover Database (NLCD) Cultivated Crops and/or Pasture/Hay classes. This approach broadly aggregates agriculture into 2 classes, which grossly overestimates the spatial extent of individual crops that are labeled for pesticide use. The approach also does not use all the available crop data, represents a single point in time, and does not account for the uncertainty in land cover data set classifications. The probabilistic crop footprint approach described herein incorporates best available information at the time of analysis from the National Agricultural Statistics Service (NASS) Cropland Data Layer (CDL) for 5 y (2008-2012 at the time of analysis), the 2006 NLCD, the 2007 NASS Census of Agriculture, and 5 y of NASS Quick Stats (2008-2012). The approach accounts for misclassification of crop classes in the CDL by incorporating accuracy assessment information by state, year, and crop. The NLCD provides additional information to improve the CDL crop probability through an adjustment based on the NLCD accuracy assessment data using the principles of Bayes Theorem. Finally, crop probabilities are scaled at the state level by comparing against NASS surveys (Census of Agriculture and Quick Stats) of reported planted acres by crop. In an example application of the new method, the probabilistic crop footprint for soybean resulted in national and statewide soybean acreages that are within the error bounds of the average reported NASS yearly soybean acreage over the same time period, whereas the method using only NLCD resulted in an acreage that is over 4 times the survey acreage. When the probabilistic crop footprint for soybean was used in a co-occurrence analysis with listed species locations, the number of potentially proximal species identified was half the number based on the standard NLCD crop footprint method (276 species with the probabilistic crop footprint vs 511 for the conventional method). The probabilistic crop footprint methodology allows for a more comprehensive and representative understanding of the potential pesticide use footprint co-occurrence with endangered species locations for use in effects determinations.


Winchell M.F.,Stone Environmental | Jones R.L.,Bayer AG | Estes T.L.,Stone Environmental
ACS Symposium Series | Year: 2011

Vegetated filter strips (VFSs) established at the downslope edge of agricultural fields have long been recommended as a management practice to reduce sediment, nutrients, and pesticides in surface runoff before it enters water bodies. Recently VFSs have been mandated as label requirements for plant protection products in Europe and North America. Several simulation models have been developed to predict the amount of pesticide active ingredients and their metabolites removed from runoff flowing through these strips. Removal efficiency is a function of several parameters and must be predicted on an event basis. The predictions of four simulation models (APEX, PRZM-BUFF, REMM, and VFSMOD) were compared using three data sets. Conditions simulated included a range of soil properties, slopes, rainfall events, and pesticide characteristics. All four models predicted reductions of pesticides in the VSFs consistent with the observed reductions, with VFSMOD simulations in closest agreement with the measured data across the three data sets. © 2011 American Chemical Society.


PubMed | Stantec Inc., Stone Environmental, Intrinsik Environmental Sciences Inc. and Bayer AG
Type: | Journal: Environmental toxicology and chemistry | Year: 2016

A probabilistic ecological risk assessment (ERA) was conducted to determine the potential effects of acute and chronic exposure of aquatic invertebrate communities to imidacloprid arising from labeled agricultural and nonagricultural uses in the United States. Aquatic exposure estimates were derived using a higher-tier refined modeling approach that accounts for realistic variability in environmental and agronomic factors. Toxicity was assessed using refined acute and chronic community-level effect metrics for aquatic invertebrates (i.e., species or taxon sensitivity distributions) developed using the best available data. Acute and chronic probabilistic risk estimates were derived by integrating the exposure distributions for different use patterns with the applicable species or taxon sensitivity distributions to generate risk curves, which plot cumulative probability of exceedance versus the magnitude of effect. Overall, the results of this assessment indicated that the aquatic invertebrate community is unlikely to be adversely affected by acute or chronic exposure to imidacloprid resulting from currently registered uses of imidacloprid in the United States. Environ Toxicol Chem 2016;9999:1-14. 2016 SETAC.

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