R5 PM Avian Sentinels of Environmental Contamination
Thursday, 17 November 2005: 1:50 PM - 5:30 PM in 321-323

(HEN-1117-564224) Empirical estimates of biomagnification factors (fish to osprey eggs) for PCDDs, PCDFs, PCBs, OCs and mercury.

Henny, C¹, Kaiser, J¹, Grove, R¹, ¹ U.S. Geological Survey, Corvallis, Oregon, USA

ABSTRACT- Limited data are available for determining biomagnification factors (BMFs) of various contaminants from fish to fish-eating birds. To estimate BMFs, it is important to understand the diet of the species of concern (on a percentage biomass basis) as well as the contaminant concentrations in each prey species or guild. The collection of eggs from a fish-eating bird of interest is generally simple, but much more effort is needed to determine the importance of each prey species (field observations at nests, and/or prey remains collections at nest sites) and then to collect the proper fish species and to apply appropriate weighting factors for residue concentrations in each prey species. An earlier paper provided the first BMF estimates for osprey nesting along the Willamette River, Oregon, in 1993. Only one BMF estimate was made for each contaminant based upon 10 osprey eggs and 25 composite samples of whole fish representing 3 species. This paper presents residue data collected along the Willamette River in 2001 (25 osprey eggs and 30 composite samples of whole fish), and provides separate BMF estimates for specific reaches of the river with somewhat different contaminant concentrations. The consistency of the BMF estimates is evaluated.

Key words: osprey, biomagnification factors, Willamette River, Oregon