1. The Relationship Between Land Use and Organochlorine Compounds in Streambed Sediment and Fish in the Central Columbia Plateau, Washingtonand Idaho, USA
- Author
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Gruber, S. J. and Munn, M. D.
- Subjects
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DDT (Insecticide) , *LAND use , *PESTICIDES - Abstract
We analyzed streambed sediment and fish in the Central Columbia Plateau in eastern Washington and Idaho for organochlorine pesticides andpolychlorinated biphenyls (SigmaPCB). Our objective was to assess the effects of land use on the occurrence and distribution of these compounds; land uses in the study area included forest, dryland and irrigated farming, and urban. We detected 16 organochlorine compounds in streambed sediment and fish tissue; fish usually had more compounds and a greater frequency of detection. The most frequently detected compound was SigmaDDT (sum of six isomers), which was found in 52% of bed sediment samples and 94% of whole fish composite samples. The othercommonly detected compounds were dimethyl tetrachloroterephthalate (DCPA), dieldrin, hexachlorobenzene, and Sigmachlordane (sum of cis- and trans-chlordane, cis- and trans-nonachlor, oxychlordane, heptachlor, and heptachlor epoxide). Forest was the only land use with no detections of organochlorine compounds in either fish or bed sediment. Hexachlorobenzene was the only organochlorine pesticide detected at concentrations that differed significantly among land uses: concentrations were higher in the dryland farming areas than in the irrigated farming or urban areas. In agricultural areas irrigated by surface water, SigmaDDT concentrations in both streambed sediment and fish tissue were related to the percentage of land irrigated by water delivered via furrows (gravity irrigation), although SigmaDDT was not detectablein bed sediments until gravity irrigation exceeded 30%. Because of the relation between gravity irrigation and soil erosion, our study supports the importance of controlling soil erosion in order to reduce the overall loading of organochlorine compounds to surface waters. [ABSTRACT FROM AUTHOR]
- Published
- 1997