Contaminant exposure in outmigrant juvenile salmon from Pacific Northwest estuaries of the United States

Abstract

To better understand the dynamics of contaminant uptake in outmigrant juvenile salmon in the Pacific Northwest, concentrations of polychlorinated biphenyls (PCBs), DDTs, polycylic aromatic hydrocarbons (PAHs) and organochlorine pesticides were measured in tissues and prey of juvenile chinook and coho salmon from several estuaries and hatcheries in the US Pacific Northwest. PCBs, DDTs, and PAHs were found in tissues (whole bodies or bile) and stomach contents of chinook and coho salmon sampled from all estuaries, as well as in chinook salmon from hatcheries. Organochlorine pesticides were detected less frequently. Of the two species sampled, chinook salmon had the highest whole body contaminant concentrations, typically 2--5 times higher than coho salmon from the same sites. In comparison to estuarine chinook salmon, body burdens of PCBs and DDTs in hatchery chinook were relatively high, in part because of the high lipid content of the hatchery fish. Concentrations of PCBs were highest in chinook salmon from the Duwamish Estuary, the Columbia River and Yaquina Bay, exceeding the NOAA Fisheries' estimated threshold for adverse health effects of 2400 ng/g lipid. Concentrations of DDTs were especially high in juvenile chinook salmon from the Columbia River and Nisqually Estuary; concentrations of PAH metabolites in bile were highest in chinook salmon from the Duwamish Estuary and Grays Harbor. Juvenile chinook salmon are likely absorbing some contaminants during estuarine residence through their prey, as PCBs, PAHs, and DDTs were consistently present in stomach contents, at concentrations significantly correlated with contaminant body burdens in fish from the same sites.

A fish of many scales: extrapolating sublethal pesticide exposures to the productivity of wild salmon populations

“…4B). The final mean mass of the control fish is consistent with masses observed in subyearling salmon collected from the Columbia River estuary (Johnson et al 2007). The reduced final mean mass of the OP-exposed fish reflects the reduced growth during the OP pulse exposure and the prolonged recovery period.…”

“…The first-year survival element of the transition matrix incorporated a sizedependent survival rate for a three-month interval encompassing the time subyearling chinook smolts spend in the estuary and nearshore habitats. The mass distributions from the organismal model were converted to length distributions by applying condition factors from data recently collected from outmigrating juvenile salmon in the lower Columbia River and estuary (Johnson et al 2007). Fish masses (g) were converted to lengths (mm) using the equation, length ¼ 10 3 (mass/0.0115) 1/3 .…”

Biomarker responses and disease susceptibility in juvenile rainbow trout Oncorhynchus mykiss fed a high molecular weight PAH mixture

“…1) [21,26]. The concentration of the individual PAHs in the fish pellets were similar to nominal values.…”

“…The absolute and relative concentrations of PAHs used in the present study were within the range detected in stomach contents of field-collected chinook salmon from contaminated estuaries in the Puget Sound, WA, and other urban areas in the Pacific Northwest [21,26]. A median dose of 3.8 mg of PAH mixture Á g fish À1 Á d À1 has been estimated [16] for juvenile chinook salmon outmigrating in the contaminated estuaries and was used to determine our dietary concentrations and profiles.…”

“…Concentrations of fluorescent aromatic compounds in bile were analyzed by high-performance liquid chromatography with fluorescence detection (HPLC/uvf) [26,27]. In brief, chromatograms were recorded at the following wavelengths pairs: 260/380 nm and 380/430 nm.…”