Publication Summary

During 2005, Ecology analyzed persistent organic pollutants in fish feed and catchable rainbow trout from ten Washington Department of Fish and Wildlife (WDFW) hatcheries and fish purchased by WDFW from one private hatchery. Fish originating from the same hatchery populations were also sampled approximately 2½ months following planting into unpolluted lakes in order to assess contaminant depuration or uptake. All feed and tissue (fillet) samples were analyzed for a variety of chlorinated pesticides, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and lipid content. A subset of feed and tissue samples was also analyzed for polychlorinated dioxins and furans.

During 2005, persistent organic pollutants (POPs) were analyzed in fish feed and catchable rainbow trout from ten Washington Department of Fish and Wildlife (WDFW) hatcheries and the fish purchased by WDFW from one private hatchery operator. Fish originating from the same hatchery populations were also sampled approximately 2½ months following planting into unpolluted lakes in order to assess contaminant depuration or uptake. All feed and tissue (fillet) samples were analyzed for a variety of chlorinated pesticides, polychlorinated biphenyls (PCBs), a select group of polybrominated diphenyl ethers (PBDEs), and lipid content. A subset of feed and tissue samples was also analyzed for polychlorinated dioxins and furans (PCDD/Fs).

Feed samples had the following mean wet weight concentrations: Total PCBs – 13.8 ng/g, Total DDT – 8.2 ng/g, Total PBDEs – <0.25 ng/g, and PCDD/F toxic equivalent – 0.75 pg/g. Fish tissue samples had the following respective mean wet weight concentrations in hatchery and planted rainbow trout: Total PCBs – 13.0 and 3.1 ng/g, Total DDT – 3.9 and 8.8 ng/g, and Total PBDEs – 0.66 ng/g for both. PCDD/F toxic equivalent averaged 0.032 pg/g in hatchery fish but was not analyzed in trout collected from lakes.

Other pesticides found in feed (f), hatchery fish (h), and planted fish (p) were: DDMU (f,h,p), dieldrin (f,h,p), hexachlorobenzene (f,h,p), pentachloroanisole (f,h,p), trans-nonachlor (f,h), cis-chlordane (f,h), trans-chlordane (f), methoxychlor (f), and toxaphene (f).

Results suggest that some portion of POP concentrations in trout from unpolluted waters may originate from hatcheries. In addition, some catchable trout contain POP concentrations above regulatory criteria when they are planted in lakes.

Link to EIM data for User Study ID DSER0015