AGRO 162 |
| Over the last sixty years, insecticides from a number of different chemical classes have been used in both agricultural and urban settings. Organochlorine (OC), organophosphate (OP) and, more recently, pyrethroid insecticides have dominated the commercial market and have been detected together in sediment samples. The large number of chemicals often present together can confound attempts to determine the hazard posed by individual components of the mixture. The objective of this study was to analyze a pre-constructed database of chemical concentrations in sediment samples collected from streambeds receiving runoff from urban environments throughout California's Central Valley. Samples were analyzed for 28 different insecticides. A censoring approach was used to eliminate negligible compounds in order to identify mixture components that dominated sample toxicity to Hyalella azteca. Seven pyrethroids and chlorpyrifos were found to account for nearly all of the toxicity in a majority of samples with tertiary mixtures of pyrethroids dominating the toxicity in most cases. |
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Synthetic Pyrethroids and Surface Water Quality Poster Session
1:00 PM-5:00 PM, Tuesday, 12 September 2006 Moscone Center -- Hall D, Poster
Sci-Mix
Division of Agrochemicals |