Environmental Health - Toxic Substances
Tracking Atrazine and a Breakdown Product (deethylatrazine) through a Drinking-Water Reservoir
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.
Related Science Features
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.