SREL Reprint #2623




Potential risk to wood storks (Mycteri americana) from mercury in Carolina Bay fish

Heather A. Brant1, Charles H. Jagoe1, Joel W. Snodgrass1,2, A. Lawrence Bryan Jr.1, and Joan C. Gariboldi1

1University of Georgia's Savannah River Ecology Laboratory, PO Drawer E, Aiken, SC 29802, USA
2Division of Life Sciences, and Consortium for Risk Evaluation with Stakeholder Participation (CRESP), Environmental and Occupational Health Sciences Institute, Rutgers University,
Piscataway, NJ 08855-1059, USA

Abstract: Carolina bays are freshwater wetlands that serve as important feeding habitats for the endangered wood stork (Mycteria americana). Water levels in these bays fluctuate greatly and tend to be acidic and rich in dissolved organic carbon (DOC), factors that favor mercury (Hg) methylation and bioaccumulation in fish. To assess potential risks to wood storks consuming mercury contaminated fish in bays, we sampled fish from 10 bays on the Savannah River Site (SRS), South Carolina, an area with documented use by wood storks. Whole body mercury concentrations in 258 fishes of three species (Erimyzon sucetta, Acantharchus pomotis and Esox americanus) commonly consumed by wood storks were determined. Risk factors for nestlings and free-ranging adults were calculated using published no and lowest observable adverse effect concentration (NOAEC and LOAEC) values for birds. Fish from higher trophic levels and those from wetlands with relatively shallow maximum depths and fluctuating water levels were more likely to exceed NOAEC and LOAEC values. Calculation of exposure rates of nestling wood storks indicated they are at highest risk during the first 10 days of the nestling periods. These calculations suggest that there is a potential concern for wood storks foraging in relatively shallow bays with fluctuating water levels, even though there is no obvious local source of mercury to these wetlands.

Keywords: Mercury; Risk; Wading birds; Fish; Wetlands

SREL Reprint #2623

Brant, H. A., C. H. Jagoe, J. W. Snodgrass, A. L. Bryan, Jr., and J. C. Gariboldi. 2002. Potential risk to wood storks (Mycteria americana) from mercury in Carolina Bay fish. Environmental Pollution 120:405-413.

To request a reprint