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Tracking Atrazine and a Breakdown Product (deethylatrazine) through a Drinking-Water Reservoir

2004 cover "Movement of atrazine and deethylatrazine through a Midwestern reservoir" was the feature article of the November 2002 Issue of the Journal of the American Water Works Association.

U.S. Geological Survey (USGS) scientists, in collaboration with Novartis Crop Protection Inc. (now Syngenta Crop Protection), have shown that understanding how and when herbicides move through reservoirs could lead to less costly solutions for protecting drinking water quality. The scientists, using an innovative combination of techniques, characterized the movement of atrazine and deethylatrazine throughout Perry Lake, a large multi-purpose reservoir in Kansas. For the first time, three-dimensional graphical views of concentrations of the two chemicals were created throughout a reservoir system for 5 distinct periods over an annual cropping cycle, including: before herbicide application, after the first significant runoff event following herbicide application, after significant runoff in the summer, after significant runoff in the fall, and before herbicide application the following spring. The study used an inexpensive and rapid analytical method using enzyme-linked immunosorbent assay to analyze samples from the reservoir for atrazine and its metabolite deethylatrazine. The study showed that spring runoff laden with triazine herbicides entered the reservoir and did not mix immediately. Concentrations varied threefold between the inlet and the public water supply intakes located at the opposite end of the reservoir. The concentration range in the outflow varied much less than the concentration in the reservoir because of mixing throughout the season near the dam and outflow. In addition, ratios of atrazine to deethylatrazine were used to determine whether atrazine in the reservoir originated from the most recent application or from past years. The characterization of seasonal, hydrologic, and land application factors in herbicide movement through the reservoir can help reservoir managers maximize use of resources to maintain water quality.


Fallon, J.D., Tierney, D.P., and Thurman, E.M., 2002, Movement of atrazine and deethylatrazine through a Midwestern reservoir: Journal of the American Water Works Association, v. 94, no. 11, p. 54-66.

Thurman, E.M., Goolsby, D.A., Meyer, M.T., Mills, M.S., Pomes, M.L., and Kolpin, D.W., 1992, A reconnaissance study of herbicides and their metabolites in surface water of the Midwestern United States using immunoassay and gas chromatography/mass spectrometry: Environmental Science and Technology, v. 26, no. 12, p. 2440-2447.

Thurman, E.M., Goolsby, D.A., Meyer, M.T., and Kolpin, D.W., 1991, Herbicides in surface waters of the Midwestern United States--The effect of spring flush: Environmental Science and Technology, v. 25, no. 10, p. 1794-1796.

Thurman, E.M., Meyer, M., Pomes, M., Perry, C.A., and Schwab, P., 1990, Enzyme-linked immunosorbent assay compared with gas chromatography/mass spectrometry for the determination of triazine herbicides in water: Analytical Chemistry, v. 62, p. 2043-2048.

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