Distribution of Inorganic and Methylmercury among Tissues in Mink (Mustela vison) and Otter (Lutra canadensis)

Total mercury and methylmercury concentrations were measured in brain, kidney, liver, and fur from several mink and otter collected in south-central Ontario. There was a large range in concentrations of both total and methylmercury. The percentage of the total mercury present as methylmercury varied among the various tissues; however, the percentage mercury found as the methyl form was relatively constant within a given tissue for all tissues in mink but highly variable in otter. For both species the highest percentage of methylmercury was found in the brain, whereas the lowest percentage was found in the kidneys for the otter and in the fur for the mink. Comparison of mercury concentrations in otter reveals that animals with higher body fat have higher mercury concentrations. Measurements of mercury in fur can be used as a general indicator of internal tissue concentrations.