Contaminant Concentrations in Juvenile Fall Chinook Salmon from Columbia River Hatcheries

Abstract

AbstractPrevious studies have reported elevated chemical contaminant concentrations in out‐migrant juvenile salmon from the lower Columbia River. Hatchery rearing is a potential exposure pathway, as contaminants have been measured in hatchery fish and feed from other regions. In this study, we analyzed for polychlorinated biphenyls (PCBs), organochlorine pesticides including dichloro‐diphenyl‐trichloroethanes (DDTs), polycyclic aromatic hydrocarbons (PAHs), and polybrominated diphenyl ethers (PBDEs) in juvenile fall Chinook salmon Oncorhynchus tshawytscha and feed from eight hatcheries (Big Creek Hatchery, Oregon Department of Fish and Wildlife; Elochoman, Cowlitz, Washougal, Klickitat, and Priest Rapids hatcheries, Washington Department of Fish and Wildlife; Little White Salmon National Fish Hatchery; and Spring Creek National Fish Hatchery) that release fish into the lower Columbia River. In feed samples, the mean concentrations of summed PCBs, summed DDTs, and summed PAHs were 14, 27, and 370 ng/g wet weight, respectively. In Chinook salmon bodies, mean concentrations of summed PCBs, summed DDTs, and summed PAHs were 17, 9.0, and 30 ng/g wet weight, respectively; metabolites of PAHs were also detected in Chinook salmon bile. Other organochlorine pesticides were detected at low levels (<5 ng/g wet weight) in feed and Chinook salmon from all hatcheries. Concentrations of PBDEs in feed and fish from all hatcheries were low (<3 and <1 ng/g wet weight, respectively). Contaminant exposure levels in hatchery Chinook salmon were generally below those associated with adverse effects on salmon health and also lower than those in field‐collected juvenile fall Chinook salmon of hatchery origin from the lower Columbia River, suggesting that the river is a more important source of contamination than are the hatcheries.