PARENT SESSION

IP11 Investigations of the Columbia River and Estuary (USA)
B113 & B114
8:00 AM - 12:00 PM, Thursday

(IP093) Contaminant Exposure in Outmigrant Juvenile Salmon from the Lower Columbia Estuary.

Johnson, Lyndal¹, Ylitalo, Gina¹, Brown, Donald¹, Lundgren, Tricia ¹, Moran, Paul¹, Anulacion, Bernadita¹, Arkoosh, Mary¹, Kagley, Anna¹, Boylen, Deborah¹, Collier, Tracy¹, ¹ NOAA Fisheries - Northwest Fisheries Science Center, Seattle, WA, United States

ABSTRACT- To better understand the dynamics of contaminant uptake in outmigrant juvenile salmon in the Lower Columbia River, contaminant concentrations were measured in juvenile Chinook salmon from the Lower Columbia River. Fish were collected in 2001 and 2002 from near the confluence of the Columbia and Willamette Rivers, near Longview, at White Island near the mouth of the estuary, and at several sites within the Lower Estuary (West Sand Island, Chinook Point, East Trestle Bay, West Trestle Bay, and Lower, Middle, and Upper Desdemona Sands). Concentrations of PCBs, PAHs, DDTs, and selected organochlorine pesticides were measured in whole bodies and/or stomach contents, and genetic analyses were conducted to identify the stock and site of origin of sampled fish. The main contaminants in salmon bodies were PCBs and DDTs. Average concentrations of PCBs ranged from 14 to 88 ng/g wet wt or 1290 to 14,200 ng/g lipid, exceeding the NOAA Fisheries estimated threshold for adverse health effects of 2400 ng/g lipid at 7 of 10 sites and in 66% of individual fish sampled. Average DDT concentrations ranged from 16 to 115 ng/g wet wt or 1750 to 27,300 ng/g lipid), among the highest levels observed in juvenile salmon from Pacific Northwest estuaries. Concentrations of PCBs and DDTs in salmon whole showed no clear spatial gradient from the Willamette/Columbia confluence to the mouth of the Columbia, but tended to be higher in larger fish collected in deeper water by purse seine than in smaller fish collected in shallow water by beach seine. Stomach contents in fish from all sites contained measurable concentrations of DDTs, PCBs, and PAHs, indicating salmon prey are a source of contamination. Hatchery feed may also be contributing to contaminant body burdens, as genetic analyses showed a substantial proportion of the fish sampled were likely of hatchery origin.

Key words: chinook salmon, Columbia River, PCBs, DDTs