Use of toe clips as a nonlethal index of mercury accumulation and maternal transfer in amphibians
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Nonlethal indices of contaminant exposure can facilitate research on the accumulation and effects of contaminants in wildlife. Here, we tested the efficacy of using amputated toes (“toe clips”), a common byproduct when marking amphibians in population and genetic studies, to determine mercury (Hg) concentrations in amphibians. We examined total mercury (THg) concentrations in American toads (Bufo americanus) collected along a contamination gradient at a Hg-contaminated field site. We found significant positive correlations between toe THg and blood THg concentrations in adult males and females collected in two different years. We also found that blood and toe clips could be used to predict maternal transfer of Hg, an important mechanism of reproductive toxicity in wildlife. Maternal toe THg concentrations were more highly correlated with egg THg concentrations than were maternal blood THg concentrations. Our results indicate that amputated toes are effective for identifying Hg concentrations in amphibians.
KeywordsAmerican toad Amphibian declines Maternal transfer Mercury Metals Nondestructive sampling
We thank S. Budischak, D. Cristol, K. Carlson-Drexler, A. Condon, M. Hepner, M. Howie, C. Ramos, J. Schmerfeld, H. Wada, and the South River Science Team for assistance and project support. We thank the landowners long the South River and the Waynesboro Parks and Recreation Department for access to sampling locations. Financial support was provided by E. I. DuPont de Nemours, Virginia Tech, and by the National Science Foundation (NSF # IOB-0615361). CMB was supported by the U.S. EPA STAR Graduate Fellowship (FP-9170040-1). EPA has not officially endorsed this publication and the views expressed herein may not reflect the views of the EPA. Research was completed with oversight from the South River Science Team, which is a collaboration of state and federal agencies, academic institutions, and environmental interests. Collecting permits and IACUC permission were obtained through WAH at Virginia Polytechnic Institute and State University.
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