Wesley Stone
Science and Products
Predicting Pesticide Levels in Streams and Rivers—Where is Water Quality at Risk?
A new interactive mapping tool predicts likely concentrations for 108 pesticides in streams and rivers across the Nation.
Pesticide mixtures show potential toxicity to aquatic life in U.S. streams, water years 2013-2017
During water years (WY) 2013–2017, the U.S. Geological Survey, National Water-Quality Assessment (NAWQA) Project, sampled the National Water Quality Network – Rivers and Streams (NWQN) year-round and reported on 221 pesticides at 72 sites across the United States in agricultural, developed, and mixed land use watersheds. The Pesticide Toxicity...
Covert, S. Alex.; Shoda, Megan E.; Stackpoole, Sarah M.; Stone, Wesley W. Causal factors for pesticide trends in streams of the United States: Atrazine and deethylatrazine
Pesticides are important for agriculture in the United States, and atrazine is one of the most widely used and widely detected pesticides in surface water. A better understanding of the mechanisms by which atrazine and its degradation product, deethylatrazine, increase and decrease in surface waters can help inform future decisions for water-...
Ryberg, Karen R.; Stone, Wesley W.; Baker, Nancy T. Influence of land use and region on glyphosate and aminomethylphosphonic acid in streams in the USA
Glyphosate is the most widely used herbicide in the United States for agricultural and non-agricultural weed control. Many studies demonstrate possible effects of glyphosate and its degradate AMPA on human and ecological health. Although glyphosate is thought to have limited mobility in soil, it is found year-round in many rivers and streams...
Medalie, Laura; Baker, Nancy T.; Shoda, Megan E.; Stone, Wesley W.; Meyer, Michael T.; Stets, Edward G.; Wilson, Michaelah C.
Data analysis considerations for pesticides determined by National Water Quality Laboratory schedule 2437
In 2013, the U.S. Geological Survey National Water Quality Laboratory (NWQL) made a new method available for the analysis of pesticides in filtered water samples: laboratory schedule 2437. Schedule 2437 is an improvement on previous analytical methods because it determines the concentrations of 225 fungicides, herbicides, insecticides, and...
Shoda, Megan E.; Nowell, Lisa H.; Stone, Wesley W.; Sandstrom, Mark W.; Bexfield, Laura M. Complex mixtures of dissolved pesticides show potential aquatic toxicity in a synoptic study of Midwestern U.S. streams
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...
Nowell, Lisa H.; Moran, Patrick W.; Schmidt, Travis S.; Norman, Julia E.; Nakagaki, Naomi; Shoda, Megan E.; Mahler, Barbara; Van Metre, Peter C.; Stone, Wesley W.; Sandstrom, Mark W.; Hladik, Michelle L. Prediction of pesticide toxicity in Midwest streams
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-...
Shoda, Megan E.; Stone, Wesley W.; Nowell, Lisa H.
Estimated annual agricultural pesticide use for counties of the conterminous United States, 2008-12
Annual county-level pesticide use was estimated for 423 herbicides, insecticides, and fungicides applied to agricultural crops grown in the conterminous United States during 2008–12. For all States except California, pesticide-use data were compiled from proprietary surveys of farm operations located within U.S. Department of Agriculture...
Baker, Nancy T.; Stone, Wesley W. Pesticides in U.S. streams and rivers: occurrence and trends during 1992-2011
During the 20 years from 1992 to 2011, pesticides were found at concentrations that exceeded aquatic-life benchmarks in many rivers and streams that drain agricultural, urban, and mixed-land use watersheds. Overall, the proportions of assessed streams with one or more pesticides that exceeded an aquatic-life benchmark were very similar between the...
Stone, Wesley W.; Gilliom, Robert J.; Ryberg, Karen R.
An overview comparing results from two decades of monitoring for pesticides in the Nation’s streams and rivers, 1992-2001 and 2002-2011
This report provides an overview of the U.S. Geological Survey National Water-Quality Assessment program and National Stream Quality Accounting Network findings for pesticide occurrence in U.S. streams and rivers during 2002–11 and compares them to findings for the previous decade (1992–2001). In addition, pesticide stream concentrations were...
Stone, Wesley W.; Gilliom, Robert J.; Martin, Jeffrey D.
Annual agricultural pesticide use for Midwest Stream-Quality Assessment, 2012-13
This report provides estimates of annual agricultural use of 190 pesticide compounds for counties and selected watersheds of Midwestern States for 2012 and 2013 compiled for subsequent analysis by the National Water-Quality Assessment Program, Midwest Stream-Quality Assessment (MSQA). One of the goals of MSQA is to characterize contaminants at...
Baker, Nancy T.; Stone, Wesley W. Pesticide Toxicity Index: a tool for assessing potential toxicity of pesticide mixtures to freshwater aquatic organisms
Pesticide mixtures are common in streams with agricultural or urban influence in the watershed. The Pesticide Toxicity Index (PTI) is a screening tool to assess potential aquatic toxicity of complex pesticide mixtures by combining measures of pesticide exposure and acute toxicity in an additive toxic-unit model. The PTI is determined separately...
Nowell, Lisa H.; Norman, Julia E.; Moran, Patrick W.; Martin, Jeffrey D.; Stone, Wesley W.
Preliminary estimates of annual agricultural pesticide use for counties of the conterminous United States, 2010-11
This report provides preliminary estimates of annual agricultural use of 374 pesticide compounds in counties of the conterminous United States in 2010 and 2011, compiled by means of methods described in Thelin and Stone (2013). U.S. Department of Agriculture (USDA) county-level data for harvested-crop acreage were used in conjunction with...
Baker, Nancy T.; Stone, Wesley W.