MP9 Metals and Bioaccumulation
Monday, 14 November 2005: 8:00 AM - 5:30 PM in Exhibit Hall

(UNR-1117-763509) Multivariate relationships among trophic level, carbon source, and trace element concentrations in organisms from a contaminated wetland.

Unrine, J¹, Romanek, C^{1, 2}, Hopkins, W³, Jackson, B³, ¹ The University of Georgia, Savannah River Ecology Laboratory, Aiken, SC, USA² The University of Georgia, Department of Geology, Athens, GA, USA³ Virginia Polytechnic Institute and State University, Blacksburg, VA, USA

ABSTRACT- Exposure to coal combustion waste (CCW) causes adverse effects in numerous aquatic organisms including fish, amphibians, and reptiles. An understanding of how trace elements from CCW behave in food webs will lead to the identification of species that may be exposed to or bioaccumulate high concentrations of contaminants based on their trophic niche. Stable isotopes of nitrogen (¹⁵N/¹⁴N) and carbon (¹³C/¹²C) were used to characterize trophic levels and carbon sources of eight species including snails (Helisoma trivolvis), clams (Corbicula fluminea), odonate larvae (Erythemis sp. and Tramea sp.), amphibian larvae (Rana catesbeiana) and fish (Gambusia holbrooki, Lepomis punctatis, and Micropterus salmoides) from a swamp contaminated by CCW. Trace element concentrations in whole organisms were determined using inductively coupled plasma mass spectrometry. Using principal components analysis we identified a group of elements (V, Mn, Fe, Zn, As, Se, and Pb) whose concentrations were negatively related to ¹⁵N, therefore tending to decrease in concentration with trophic level. Amphibian larvae, followed by clams and snails, tended to have the highest concentrations of these elements. A second group of elements (Cd, Cu) had concentrations that were not related to ¹⁵N, but were strongly negatively related to ¹³C. Concentrations of these elements were highest in clams, which relied heavily on sediment as a source of nutrition. Finally, Hg concentrations increased with ¹⁵N and dry body mass. Clams and amphibian larvae accumulated Hg concentrations similar to those in fish that occupied higher trophic levels, but these primary consumers and fish were constituents of different food chains. We concluded that primary consumers tended to have the highest concentrations of trace elements in this CCW impacted swamp, but the particular elements that accumulated to the highest concentrations varied greatly among species.

Key words: Coal combusiton waste, Stable isotope, Principal components analysis, Trace element