Bioaccumulation of Methylmercury in Neovison vison (Schreber, 1777) Populations of the Susquehanna River Valley

Being the longest non-navigable river on the eastern coast of the United States, the Susquehanna River and the surrounding areas support a vast number of plants, animals, and other organisms, creating a vast and complex food web within a large and biodiverse ecosystem. One of the most prominent and essential organisms within this food web is the American mink (Neovison vison). In recent years, studies have been conducted to determine the level of biomagnification of methylmercury in terrestrial organisms that reside at higher trophic levels. This particular study has found that American mink populations residing in the Susquehanna River Valley of Pennsylvania are reliable indicators of bioaccumulation of methylmercury due to their role as piscivorous carnivores residing at a high trophic level of the terrestrial food web. Analysis of methylmercury concentrations of 166 hair samples from collected mink specimens yielded 111 samples with concentrations in excess of the toxicity threshold of 1 mg kg-1 body weight. Furthermore, our data suggest that although mercury contamination is a global concern, geographical location of mercury producers, such as coal-burning power plants, and the relationship to the location of mink populations may be a large factor in bioaccumulation of mercury. In particular, samples taken from mink specimens within habitats in the northeastern region of Pennsylvania contained higher concentrations of methylmercury as well as a larger quantity of samples containing concentrations higher than the toxicity threshold than in samples from other regions of the state.