HEAVY-METAL CONCENTRATIONS IN FEATHERS OF COMMON LOONS (GAVIA-IMMER) IN THE NORTHEASTERN UNITED-STATES AND AGE-DIFFERENCES IN MERCURY LEVELS

Feathers serve as a useful, non-destructive approach for biomonitoring some aspects of environmental quality. Birds can eliminate over 90% o f their body burden of mercury by sequestration in growing feathers, a nd they molt their feathers at least annually. Thus mercury concentrat ions should not vary in avian feathers as a function of age. We tested the null hypothesis that there are no age differences in the concentr ations of mercury, lead, cadmium, selenium, copper, chromium and manga nese in the feathers of immature and adult common loons Gavia immer fr om the Northeastern United States where the species is declining. Adul ts had significantly higher mean levels of mercury (20245 ppb) than im mature loons (9677 ppb), but there were no age-related differences for other elements. Even with the small number of immatures, females had significantly higher levels of mercury than males, although the gender difference was not significant for adults.