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| Title | Wapato Lake - Pesticide Levels, Sediment Bioassays, and Abundance of Benthic Invertebrates. Memo to M. Linden and B. Barwin, Central Regional Office. | |||
| Month-Year Published | July 1977 | |||
| Online Availability |
1871 kilobytes, requires version 4.0 or later of Adobe Acrobat Reader Software get Acrobat Reader
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| Short Description |
Pesticides, lead, and arsenic were analyzed in composite samples of whole rainbow trout, rainbow trout fillets, and bottom sediments collected August-September 1996 from Wapato Lake, located in the fruit orchards above Lake Chelan. Lead arsenate was used historically to control codling moths in apple trees. (Also see abstract below) | |||
| Publication Number | 97-e05 | |||
| Author(s) | Johnson, A. | |||
| Print Availability |
Not maintained in stock. Copy must be made from archive version.
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| Number of pages | 73 pp. | |||
| Keywords | bill, bioassay, DDT, fish, invertebrates, lake, lead, pesticides, sediment, stream, toxin, TREE, trees | |||
| Subject Waterbodies |
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| Abstract | Long Description |
Pesticides, lead, and arsenic were analyzed in composite samples of whole rainbow trout, rainbow trout fillets, and bottom sediments collected August-September 1996 from Wapato Lake, located in the fruit orchards above Lake Chelan. Lead arsenate was used historically to control codling moths in apple trees. DDT, its metabolites DDD and DDE, dieldrin, hexachlorobenzene, dacthal, and chlorpyrifos were detected in the fish tissue samples. All concentrations were low, generally less than 10 ug/Kg (parts per billion), and do not represent a hazard to human health or wildlife. However, high concentrations of DDD (to 650 ug/Kg) and DDE (to 470 ug/Kg) were found in the lake sediments. The sediments were toxic in Microtox bioassays and benthic macroinvertebrates were virtually absent. These findings are consistent with the presence of a toxin. Although pesticides may not be involved, the DDD concentrations are high enough to have a severe adverse effect on benthic invertebrate communities. Comparable or higher concentrations of DDD and DDE have been reported in the sediments of Roses Lake further downstream in the drainage. Lead and arsenic were not detectable in Wapato Lake rainbow trout. The concentrations found in the sediments, approximately 20 mg/Kg and 3 mg/Kg, respectively, are at natural background levels. |
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This page last updated July 7, 2009
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