DISTRIBUTIONS OF TRACE ELEMENTS IN PEAT BAY AT THE SAVANNAH RIVER SITE, AIKEN, SOUTH CAROLINA

The Savannah River Site in Aiken, South Carolina was a nuclear weapons production facility until the shutdown of its reactors in 1991. It is believed that contaminants were released through these man-made processes. Peat Bay is a peat-containing wetland located down-gradient from a reactor and a cooling reservoir known as L-Lake. Five cores from Peat Bay were analyzed for trace elements and petrographic composition. Sixty elements were analyzed in fifty samples from the five cores. Preliminary results showed that certain layers of peat had higher concentrations of trace elements than others. For instance, in core-1, 54 of the 60 elements had their highest concentrations in the 4-6 cm increment of the core. Additional correlations occurred in other cores. Natural trends were sometimes readily distinguishable from anthropogenically derived ones. For example, certain zones with high concentrations of Si, Al, K, Mg, and Fe could easily be accounted for by the presence of clay or mica-rich layers in the peat. On the other hand, various rare earth elements exhibited trends that indicated anthropogenic sources. For example, the elements europium, samarium, erbium, holmium, and uranium showed significant positive correlations within the 8-30 cm depth for cores 4 and 5. Europium is a man-made element used in nuclear control applications. Uranium is used as fuel for nuclear reactors; and erbium, samarium, and holmium are used in nuclear reactors. In core 4, and less prominently in core 5, an anomalously high peak occurred near the 8-10 cm depth for all of these elements. Cores 4 and 5 were closest to L-Lake and thus closer to the presumed source of groundwater contamination. These anomalous peaks also tended to correlate vertically with changes in petrographic composition, suggesting possible preferential concentration of certain elements because of differences in physico-chemical properties of the peat layers.