| Autor: |
Custer CM; U.S. Geological Survey, Upper Midwest Environmental Sciences Center, 2630 Fanta Reed Rd., La Crosse, WI, 54603, USA. ccuster@usgs.gov., Custer TW; U.S. Geological Survey, Upper Midwest Environmental Sciences Center, 2630 Fanta Reed Rd., La Crosse, WI, 54603, USA., Dummer PM; U.S. Geological Survey, Upper Midwest Environmental Sciences Center, 2630 Fanta Reed Rd., La Crosse, WI, 54603, USA., Goldberg D; U.S. Geological Survey, National Wildlife Health Center, 6006 Schroeder Rd., Madison, WI, 53711, USA., Franson JC; U.S. Geological Survey, National Wildlife Health Center, 6006 Schroeder Rd., Madison, WI, 53711, USA. |
| Abstrakt: |
Tree swallow (Tachycineta bicolor) eggs and nestlings were collected from 16 sites across the Great Lakes to quantify normal annual variation in total polychlorinated biphenyl (PCB) exposure and to validate the sample size choice in earlier work. A sample size of five eggs or five nestlings per site was adequate to quantify exposure to PCBs in tree swallows given the current exposure levels and variation. There was no difference in PCB exposure in two randomly selected sets of five eggs collected in the same year, but analyzed in different years. Additionally, there was only modest annual variation in exposure, with between 69% (nestlings) and 73% (eggs) of sites having no differences between years. There was a tendency, both statistically and qualitatively, for there to be less exposure in the second year compared to the first year. |
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