T9 AM Bioaccumulation and Biomagnification
Tuesday, 15 November 2005: 8:00 AM - 11:40 AM in 339-340
(MAU-1117-723414) Bioaccumulation and trophic transfer of polychlorinated biphenyls (PCBs) from aquatic and terrestrial insects to tree swallows.
Maul, J.1, Belden, J.1, Schwab, B.1, Whiles, M.1, Spears, B.2, Farris, J.3, Lydy, M.1, 1 Southern Illinois University, Carbondale, IL, USA2 U.S. Fish and Wildlife Service, Spokane, WA, USA3 Arkansas State University, State University, AR, USA
ABSTRACT- Insectivorous passerines bioaccumulate polychlorinated biphenyls (PCBs) via trophic transfer processes. Tree swallows (Tachycineta bicolor) are frequently used for estimating PCB bioaccumulation, yet focus on the specific trophic links between contaminated sediment and bird has been limited. Bioaccumulation of PCBs from sediment to tree swallows was examined with focus on trophic pathways by simultaneously examining PCBs in emergent aquatic and terrestrial insects and gut contents of nestlings. Total PCB concentrations increased from sediment (123.65 ± 15.93 
g/kg) to tree swallow nestlings (2827.76 ± 505.67 g/kg), with emergent aquatic insects, terrestrial insects, and gut content samples having intermediate concentrations. Biota-sediment accumulation factors (BSAFs) varied among congeners for tree swallow nestlings and male and female Chironomus spp. For nestlings, the highest BSAF was for the mono-ortho substituted congener 118. Nestling biomagnification values were similar for gut contents and female Chironomus spp. suggesting this diet item may be the main contributor to the overall PCB transfer to nestlings. However, gut content samples were highly variable and on a PCB congener pattern basis, may have been influenced by other taxa such as terrestrial insects. Considering dietary plasticity of many insectivorous birds, this work suggests that a variety of potential food items should be considered when examining PCB accumulation in insectivorous passerines.
Key words: BSAF, polychlorinated biphenyls, tree swallow, trophic transfer