Overview

The NAWQA Pesticide National Synthesis Project, which began in 1992, is a national-scale assessment of the occurrence and behavior of pesticides in streams and ground water of the United States and the potential for pesticides to adversely affect drinking-water supplies or aquatic ecosystems.

Features

• Prediction of Atrazine Concentrations: Estimate atrazine concentrations in your stream with this interactive model and mapping tool.
  Watershed Regressions for Pesticides (WARP) Atrazine Model (BETA demonstration)
• The Quality of Our Nation's Waters
  Pesticides in the Nation's Streams and Ground Water, 1992-2001
  Released March 2, 2006

• Full Report
• Fact Sheet
• Frequently Asked Questions
• Supporting Information

• Recent Publications

• Regression models for explaining and predicting concentrations of organochlorine pesticides in fish from United States streams . Environmental Toxicology and Chemistry, v. 28, n. 6, pp. 1346-1358. (Supporting Info)
• Comparison of pesticide concentrations in streams at low flow in six metropolitan areas of the United States: Environmental Toxicology and Chemistry, Vol. 27, No. 2, pp. 288–298
  
• Relative toxicity and occurrence patterns of pesticide mixtures in streams draining agricultural watersheds dominated by corn and soybean production: Integrated Environmental Assessment and Management, v.3, n.1, pp. 90-100 (2007)
• Response of stream chemistry during base flow to gradients of urbanization in selected locations across the conterminous United States: USGS SIR 2007-5083 (2007)
• Pesticides in the Nation's Streams and Ground Water; Environmental Science and Technology, v. 41, n.10, pp. 3408–3414 (2007)
• The geochemistry of pesticides. In: Environmental Geochemistry (ed. B. S. Lollar), Volume 9 of Treatise on Geochemistry (eds. H.D.Holland and K.K. Turekian), Elsevier—Pergamon, Oxford, UK, on-line edition, 43 p. (2007)
• How well can we predict the toxicity of pesticide mixtures to aquatic life? Integrated Environmental Assessment and Management, v. 3, n.3, pp. 364-372 (2007)
• Development and application of health-based screening levels for use in water-quality assessments: USGS SIR 2007-5106, 12 p. (2007)

Dieldrin is an organochlorine pesticide that had its registration cancelled decades ago because of its tendency to bioaccumulate in tissues of organisms, hazard to wildlife, carcinogenicity, and other chronic effects. Although not used in the United States since the late 1980s, dieldrin breaks down slowly in the environment. Its continued presence in U.S. soils and streams results from the past use of dieldrin and aldrin (another organochlorine insecticide that degrades to dieldrin in the environment). This map shows the predicted probability of fish in streams having whole-fish concentrations of dieldrin greater than 120 µg/kg, the upper end of the range of benchmarks for protection of fish-eating wildlife, and 81 µg/kg, the lower end of this range. The area with the most extensive potential concern is the central Corn Belt, where most streams have more than a 5 percent chance of exceeding the lower benchmark and many streams have more than a 50 percent chance of exceeding this benchmark. The predictions assume a fish lipid content of 6.2 percent, which is a national average for fish. These predictions were made using a statistical regression model developed from dieldrin concentrations in whole fish measured by the USGS NAWQA Program at 648 stream sites across the conterminous United States during 1992-2001. Predictor variables in the regression model include estimates of past agricultural use, an indicator of past use for termite control, variables representing watershed characteristics or geographic location, and fish lipid content. Empirical models such as this one can provide a cost-effective predictive tool to supplement existing monitoring data, assess the need for further monitoring, and guide the design and location of future sampling.

For further details, see Nowell, L.H., Crawford, C.G., Gilliom, R.J., Nakagaki, N., Stone, W.W., Thelin, G.P., and Wolock, D.W., 2009, Regression models for explaining and predicting concentrations of organochlorine pesticides in fish from United States streams Environmental Toxicology and Chemistry, v. 28, n. 6, pp. 1346-1358. http://water.usgs.gov/nawqa/pnsp/pubs/i552-8618-28-6-1346.pdf

Posted on June 8, 2009