Elemental and organochlorine residues in bald eagles from Adak Island, Alaska

Adak Island is a remote island in the Aleutian Island archipelago of Alaska (USA) and home to various military activities since World War II. To assess the contaminant burden of one of Adak Island's top predators, livers and kidneys were collected from 26 bald eagle (Haliaeetus leucocephalus) carcasses between 1993 and 1998 for elemental and organochlorine analyses. Mean cadmium, chromium, mercury, and selenium concentrations were consistent with levels observed in other avian studies and were below toxic thresholds. However, elevated concentrations of chromium and mercury in some individuals may warrant concern. Furthermore, although mean polychlorinated biphenyl and pp'-dichlorodiphenyldichloroethylene concentrations were below acute toxic thresholds, they were surprisingly high given Adak Island's remote location.