PH13 Metals in the Environment: Dietary Concerns in Aquatic Systems
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(PH155) Dietary mercury exposure and bioaccumulation in amphibian larvae inhabiting Carolina bay wetlands.
Unrine, J1, Jagoe, C1, Brinton, A1, Brant, H1, Garvin, N1, 1 The University of Georgia, Savannah River Ecology Laboratory, Aiken, SC, USA
ABSTRACT- Mercury from atmospheric deposition tends to accumulate in biota inhabiting isolated wetlands that are critical breeding sites for amphibians; however, little is known about mercury exposure and bioaccumulation in amphibian larvae. Inorganic mercury and methylmercury concentrations were measured both in guts and remaining carcasses of southern leopard frog (Rana sphenocephala) larve from 10 isolated depression wetlands (Carolina bays) in South Carolina, USA. Significant variation among wetlands in methylmercury and inorganic mercury concentrations existed both in guts and carcasses. There was a moderate negative correlation between dissolved organic carbon concentration in wetlands and mean inorganic mercury concentrations in guts. There was also a weak positive correlation between pH in wetlands and mean methylmercury concentrations in carcasses. Mercury concentrations in carcasses were not correlated with mercury concentrations in guts. The ratio of methylmercury to inorganic mercury decreased with increasing total mercury concentration in guts and in larvae, but the rate of decrease was highly variable among bays. Ratios of concentrations in carcasses to concentrations in guts were inversely related to gut concentrations, suggesting an inverse relationship between exposure concentration and bioaccumulation factor. Mercury concentrations in carcasses in some bays were within the range of concentrations at which adverse effects have been observed in laboratory studies of Rana sphenocephala .
Key words: Bioaccumulation, Trophic transfer, Amphibian, Mercury