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Mercury contamination in wildlife has rarely been studied in the Southern Appalachians despite high deposition rates in the region. From 2006 to 2008 we sam- pled feathers from 458 birds representing 32 species in the Southern Appalachians for total mercury and stable isotope d 15 N. Mercury concentrations (mean ± SE) averaged 0.46 ± 0.02 l gg -1 (range 0.01-3.74 l gg -1 ). Twelve of 32 species had individuals (7 % of all birds sampled) with mercury concentrations higher than 1 l gg -1 . Mercury concentrations were 17 % higher in juveniles compared to adults (n = 454). In adults, invertivores has higher mercury levels compared to omnivores. Mercury was highest at low- elevation sites near water, however mercury was detected in all birds, including those in the high elevations (1,000-2,000 m). Relative trophic position, calculated from d 15 N, ranged from 2.13 to 4.87 across all birds. We fitted linear mixed-effects models to the data separately for juveniles and year-round resident adults. In adults, mercury concentrations were 2.4 times higher in invertivores com- pared to omnivores. Trophic position was the main effect explaining mercury levels in juveniles, with an estimated 0.18 ± 0.08 l gg -1 increase in feather mercury for each one unit rise in trophic position. Our research demonstrates that mercury is biomagnifying in birds within this terrestrial mountainous system, and further research is warranted for animals foraging at higher trophic levels, particularly those associated with aquatic environments downslope from montane areas receiving high mercury deposition.

Much of the mercury contamination in aquatic biota originates from coal-fired power plants, point sources that release mercury into the atmosphere. Understanding mercury dynamics is primarily important because of the toxic threat mercury poses to wildlife and humans through the consumption of contaminated fish. In this study, we quantified the relative importance of proximity to coal-fired power plants on mercury accumulation in two fish species of different trophic positions. Fish, water and sediment were collected and analyzed from 14 lakes, seven near to (10 km) and seven far from (30 km) coal-fired power plants. Lower tissue mercury and higher tissue selenium concentrations were measured in fish collected near power plants. Moreover, mercury accumulation in fish was driven by biotic characteristics (e.g., trophic position, total length, age), waterbody characteristics (e.g., pH, dissolved organic carbon and sulfate) and distance from power plants. Proximity to an atmospheric point-source of mercury and selenium, such as a coal-fired power plant, affects the quantities of mercury and selenium accumulated in fish tissue. Differences in accumulation are hypothesized to be driven in part by selenium-mitigated reductions in fish tissue mercury near power plants. Although reduced fish tissue mercury in systems near power plants may decrease mercury-specific risks to human consumers, these benefits are highly localized and the relatively high selenium associated with these tissues may compromise ecological health.