| Reproduction, Embryonic Development, and Maternal Transfer of Contaminants in the Amphibian Gastrophryne carolinensis William Alexander Hopkins,1,2 Sarah Elizabeth DuRant,1,2 Brandon Patrick Staub,1 Christopher Lee Rowe,3 and Brian Phillip Jackson1,4 1Savannah River Ecology Laboratory, University of Georgia, Aiken, South Carolina, USA; 2Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA; 3Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Solomons, Maryland, USA; 4Departments of Chemistry and Earth Sciences, Dartmouth College, Hanover, New Hampshire, USA Abstract
Although many amphibian populations around the world are declining at alarming rates, the cause of most declines remains unknown. Environmental contamination is one of several factors implicated in declines and may have particularly important effects on sensitive developmental stages. Despite the severe effects of maternal transfer of contaminants on early development in other vertebrate lineages, no studies have examined the effects of maternal transfer of contaminants on reproduction or development in amphibians. We examined maternal transfer of contaminants in eastern narrow-mouth toads (Gastrophryne carolinensis) collected from a reference site and near a coal-burning power plant. Adult toads inhabiting the industrial area transferred significant quantities of selenium and strontium to their eggs, but Se concentrations were most notable (up to 100 µg/g dry mass) . Compared with the reference site, hatching success was reduced by 11% in clutches from the contaminated site. In surviving larvae, the frequency of developmental abnormalities and abnormal swimming was 55-58% higher in the contaminated site relative to the reference site. Craniofacial abnormalities were nearly an order of magnitude more prevalent in hatchlings from the contaminated site. When all developmental criteria were considered collectively, offspring from the contaminated site experienced 19% lower viability. Although there was no statistical relationship between the concentration of Se or Sr transferred to eggs and any measure of offspring viability, our study demonstrates that maternal transfer may be an important route of contaminant exposure in amphibians that has been overlooked. Key words: amphibian, coal combustion, development, embryo, maternal transfer, mercury, reproduction, selenium, strontium. Environ Health Perspect 114: 661-666 (2006) . doi:10.1289/ehp.8457 available via http://dx.doi.org/ [Online 8 December 2005]
Address correspondence to W.A. Hopkins, Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, 100 Cheatham Hall, Blacksburg, VA 24061 USA. Telephone: (540) 231-7292. Fax: (540) 231-7580. E-mail: hopkinsw@vt.edu We thank J. Baionno, M. Komoroski, D. Scott, D. Harrelson, J. Unrine, and J. Snodgrass for providing assistance. Support was provided by the Eppley Foundation, the U.S. Environmental Protection Agency (STAR R-82908701) , the U.S. Department of Energy [Environmental Remediation Sciences Division/Office of Biological and Environmental Research, award DE-FC09-96SR18546 to the University of Georgia (UGA) Research Foundation], and a young faculty award from the UGA. The authors declare they have no competing financial interests. Received 30 June 2005 ; accepted 8 December 2005.
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