Evidence of Long-Range Atmospheric Transport and Degradation of Atrazine and Deethylatrazine

Abstract

The herbicide, atrazine, was detected in rainfall during 1992-1994 in the central United States, in rainfall in the Great Lakes along the border of Canada, and in rainfall and snow in southern Germany and the Bavarian Alps. The concentrations of atrazine varied from the detection limit of 0.05 Îg/L to 1-2 Îg/L as determined by gas chromatography/mass spectrometry and enzyme-linked immunosorbent assay. The herbicide was detected from 100 to 300 kilometers from the nearest corn field, which indicates long-range transport in the atmosphere. The metabolite, deethylatrazine, was also detected in rainfall at concentrations, which were approximately 50% that of parent compound. The ratio of deethylatrazine to atrazine was considerably greater than that found in streams of the areas during the same time period. This result suggests that there is degradation occurring during atmospheric transport. Furthermore, an intermediate of photodecomposition, atrazine amide, was tentatively identified using gas chromatography/mass spectrometry in samples of rainfall form the midwestern United States. Previous laboratory studies suggest that both ozone and photodecomposition reactions will generate deethylatrazine and that the pathway passes through the atrazine amide. The data suggest that the amount of atrazine in rainfall of the United States and western Europe would be 50 to 70% higher than estimated in earlier studies because of degradation of atrazine to deethylatrazine in the atmosphere and the subsequent deposition of deethylatrazine.

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Thurman, E.M., Goolsby, D.A., Meyer, M.T., Cromwell, A.E., Dankwardt, Andrea, and Hock, Bertold, 1995, Evidence of long-range atmospheric transport and degradation of atrazine and deethylatrazine, in Preprints of Papers presented at the 209th ACS National Meeting, Anaheim, California, April 2-7, 1995: American Chemical Society, Division of Environmental Chemistry, v. 35, no. 1, p. 286-287.

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