, Volume 11, Issue 2, pp 154–163 | Cite as

Selenium:Mercury Molar Ratios in Bullfrog and Leopard Frog Tadpoles from the Northeastern United States

  • Joanna BurgerEmail author
  • Jeremy Feinberg
  • Christian Jeitner
  • Michael Gochfeld
  • Mark Donio
  • Taryn Pittfield
Original Contribution


Vertebrates experience adverse effects from methylmercury, largely obtained through their food. Selenium has the potential to reduce the toxic effects of methylmercury (and vice versa). In this paper, we examine the selenium:mercury molar ratios in tadpoles (Lithobates sphenocephalus, Lithobates catesbeianus (formerly Rana), and a newly documented leopard frog species currently referred to as R. sp. nov.) and fully formed leopard frog metamorphs. There were no significant differences in metal levels between the two leopard frog species, and data were therefore combined. Selenium:mercury molar ratios varied from 19 to 38 for bullfrog tadpoles, from 16 to 330 for leopard frog tadpoles, and from 7 to 17 for leopard frog metamorphs. Leopard frog tadpoles with less than 45 days exposure to field conditions had significantly higher molar ratios than other tadpoles and leopard frog metamorphs. There were significant locational differences for the molar ratios of bullfrogs, and leopard frog tadpoles with more than 45 days of field exposure. At the sites where we were able to sample both leopard frog tadpoles and leopard frog metamorphs, there were significant differences between the two distinct life stages. Most of the variation in the ratio was accounted for by selenium levels, field sites, and exposure period.


selenium mercury molar ratios leopard frog bullfrog methylmercury 



We thank the many people who have discussed mercury, selenium, and molar ratios with us, including Melanie Lémire, Kate Mahaffey, Donna Mergler, Nick Ralston, Rita Schoeny, Alan Stern, Helmut Zarbl, and Tim Green, as well as two anonymous reviewers. The views and conclusions expressed in this paper are solely those of the authors, and do not reflect the funding agencies. This research was partly supported by the Brookhaven National Laboratory, Foundation for Ecological Research in the Northeast, New York State Biodiversity Research Institute, Long Island Community Foundation, the Rutgers University Graduate School of New Brunswick and Graduate Program in Ecology and Evolution, NIEHS Center Grant (P30ES005022), the Consortium for Risk Evaluation with Stakeholder Participation (Department of Energy, DE-FC01-06EW07053), and EOHSI. This research was conducted under a Rutgers University Protocol, and samples were collected under appropriate state permits.


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Copyright information

© International Association for Ecology and Health 2014

Authors and Affiliations

  • Joanna Burger
    • 1
    • 2
    • 3
    Email author
  • Jeremy Feinberg
    • 2
    • 3
  • Christian Jeitner
    • 1
    • 2
  • Michael Gochfeld
    • 2
    • 4
  • Mark Donio
    • 1
    • 2
  • Taryn Pittfield
    • 1
    • 2
    • 3
  1. 1.Division of Life SciencesRutgers UniversityPiscatawayUSA
  2. 2.Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayUSA
  3. 3.Graduate Program in Ecology and EvolutionRutgers UniversityPiscatawayUSA
  4. 4.Environmental and Community Medicine, Robert Wood Johnson Medical SchoolRutgers UniversityPiscatawayUSA

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