Notes
USGS report (Exhibit AR034767) on pesticides detected in urban stream water during rainstorms in King County, Washington, in collaboration with Washington State Department of Ecology and King County. Twenty-three of 98 pesticides sampled were detected across 12 study sites in 10 urban watersheds; concentrations of five insecticides (carbaryl, chlorpyrifos, Diazinon, gamma-HCH/Lindane, Malathion) exceeded NAS/NAE recommended maximum concentrations set to protect aquatic life. Pesticides including 2,4-D, MCPP, Diazinon, atrazine, simazine, dichlobenil, and pentachlorophenol were detected; retail sales data from 10 home and garden stores in King County and Snohomish County correlated with stream detections. Water samples from Lyon Creek showed chronic toxicity to Ceriodaphnia dubia and Selenastrum capricornutum. Study sites included Thornton Creek, Lyon Creek, Longfellow Creek, Sunset Creek, Lewis Creek, Miller Creek, Des Moines Creek, Little Soos Creek, and Rock Creek (reference site).