| Summary: | The uptake of persistent polychlorinated hydrocarbons (PCHs) by four avian species was investigated at upper trophic levels of two aquatic food chains of the lower Fox River and Green Bay, Wisconsin. ccumulation of total and specific planar polychlorinated biphenyls (PCBs), polychlorinated dibenzofurans (PCDFs), polychlorinated dibenzo-p-dioxin (PCDDs), and H4IIE rat hepatoma cell bioassay-derived 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TCDD-EQ) was evaluated in Forster's tern (Sterna forsteri) and common tern (Sterna hirundo) chicks, and in tree swallow (Tachycineta bicolor) and red-winged blackbird (Agelaius phoeniceus) nestlings from colonies nesting in several locations within the watershed. oncentrations of the PCHs were greatest in eggs and chicks of the two tern species, less in the tree swallows and least in the red-winged blackbirds. oung of all four speciesaccumulated total PCBs, PCB congeners 77, 105, 126, and 169, and TCDD-EQ. he young birds also accumulated small concentrations of several 2,3,7,8-substituted PCDF and PCDD congeners. ptake rates for certain of the PCHs for the Forster's tern chicks were 15 ug/day for total PCBs, 70, 200, 6.5, and 0.14 ng/day for PCB congeners 77, 105, 126, and 169 respectively, and 270 pg/day for TCDD-EQ. rinciple components analysis revealed that the patterns of PCH concentration in the samples were influenced by species of bird, their age (or length of exposure) and nesting location. ollectively, our findings demonstrate that exposure of avian species to contaminants derived from aquatic food chains can be characterized and quantified for the purposes of ecological risk assessment.
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