W. C. Bridges

Bald eagles (Haliaeetus leucocephalus) are a sentinel species used to monitor concentrations of environmental contaminants such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCs) in North America. Bald eagles were very slow to recover after the ban of PCBs and OCs because of their environmental persistence. The bald eagle population at Voyageurs National Park (VNP) provides an opportunity to assess temporal and spatial trends of persistent environmental contaminants. Nestling bald eagle plasma samples were analyzed for PCBs and OCs for the past 14 years. Total PCBs...

Bald eagles (Haliaeetus leucocephalus) have been utilized as a biosentinel of aquatic ecosystem health in the Great Lakes Region since the early 1960s. Bald eagle populations have been monitored at Voyageurs National Park (VNP), Minnesota, since 1973. For the past 20 years, researchers have collected feathers from nestling bald eagles to assess their dietary exposure to mercury (Hg) on Rainy, Kabetogama, and Namakan lakes in VNP. Current geometric mean concentrations have declined by 77.4% since 1989 at VNP. While all samples from 1985 to 1989 had detectable concentrations of Hg, 10%...