Prediction of pesticide toxicity in Midwest streams

Journal of Environmental Quality
By: , and 



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.

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Publication type Article
Publication Subtype Journal Article
Title Prediction of pesticide toxicity in Midwest streams
Series title Journal of Environmental Quality
DOI 10.2134/jeq2015.12.0624
Volume 45
Issue 6
Year Published 2016
Language English
Publisher ACSESS
Contributing office(s) California Water Science Center, Indiana Water Science Center
Description 9 p.
First page 1856
Last page 1864
Country United States
Other Geospatial Midwest
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