Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 1688
Title: Pyrethroid insecticides in urban salmon streams of the Pacific Northwest
Author: D. P. Weston, A. M. Asbell, S. A. Hecht, N. L. Scholz, M. J. Lydy
Publication Year: 2011
Journal: Environmental Pollution
Volume: 159
Pages: 3051-3056
Keywords: pyrethroid, bifenthrin,insecticides, urban pollution, Hyalella azteca

Urban streams of the Pacific Northwest provide spawning and rearing habitat for a variety of salmon species, and food availability for developing salmon could be adversely affected by pesticide residues in these waterbodies. Sediments from Oregon and Washington streams were sampled to determine if current-use pyrethroid insecticides from residential neighborhoods were reaching aquatic habitats, and if they were at concentrations acutely toxic to sensitive invertebrates. Approximately one-third of the 35 sediment samples contained measurable pyrethroids. Bifenthrin was the pyrethroid of greatest concern with regards to aquatic life toxicity, consistent with prior studies elsewhere. Toxicity to Hyalella azteca and/or Chironomus dilutus was found in two sediment samples at standard testing temperature (23 C), and in one additional sample at a more environmentally realistic temperature (13 C). Given the temperature dependency of pyrethroid toxicity, low temperatures typical of northwest streams can increase the potential for toxicity above that indicated by standard testing protocols.