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Occurrence and fate of pesticides in four contrasting agricultural settings in the United States

Journal of Environmental Quality

By:
, , , ,
DOI: 10.2134/jeq2007.0166

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Abstract

Occurrence and fate of 45 pesticides and 40 pesticide degradates were investigated in four contrasdng agricultural settings - in Maryland, Nebraska, California, and Washington. Primary crops included corn at all sites, soybeans in Maryland, orchards in California and Washington, and vineyards in Washington. Pesticides and pesticide degradates detected in water samples from all four areas were predominandy from two classes of herbicides - triazines and chloroacetanilides; insecticides and fungicides were not present in the shallow ground water. In most samples, pesticide degradates gready exceeded the concentrations of parent pesticide. In samples from Nebraska, the parent pesticide atrazine [6-cHoro-N-ethyl-N???-(1-methylethyl)-1,3,5-triazine-2,4- diamine] was about the same concentration as the degradate, but in samples from Maryland and California atrazine concentrations were substantially smaller than its degradate. Simazine [6-chloroN,N???-diethyl-1,3,5-triazine-2,4-diarnine] , the second most detected triazine, was detected in ground water from Maryland, California, and Washington. Metolachlor [2-chloro-N-(2-ethyl6-merhylphenyl)-N- (2-methoxy-1-methylerhyl)acetamide] rarely was detected without its degradates, and when they were detected in the same sample metolachlor always had smaller concentrations. The Root-Zone Water-Quality Model was used to examine the occurrence and fate of metolachlor at the Maryland site. Simulations accurately predicted which metolachlor degradate would be predominant in rhe unsaturated zone. In analyses of relations among redox indicators and pesticide variance, apparent age, concentrations of dissolved oxygen, and excess nitrogen gas (from denitrification) were important indicators of the presence and concentration of pesticides in these ground water systems. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Occurrence and fate of pesticides in four contrasting agricultural settings in the United States
Series title:
Journal of Environmental Quality
DOI:
10.2134/jeq2007.0166
Volume
37
Issue:
3
Year Published:
2008
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
1116
Last page:
1132
Number of Pages:
17