TRACE ELEMENT DISTRIBUTION IN AN ORGANIC-RICH WETLAND AT THE SAVANNAH RIVER SITE, SOUTH CAROLINA

The Savannah Rive Site (SRS) in Aiken, South Carolina was a nuclear weapons production facility until it shutdown in 1991. It is believed that contaminants were released through these man-made processes. Peat Bay is a peat containing wetland located at SRS and is down gradient from an old reactor and a cooling reservoir known as L-Lake. Five cores were taken from this site and analyzed for trace elements and petrographic correlations. Sixty elements were analyzed in fifty samples taken from the five cores. The results were then graphed for each element of each core and observed for possible correlation. Preliminary results shows there are indeed certain layers of peat that have higher concentrations of elements than others. For instance, in core 1, 54 of the 60 elements had the highest concentrations in the 4-6 cm increment of the 1.5 ft long core. Other correlations were drawn from core to core. In general, natural trends were distinguishable from anthropogenically derived ones. For example, in some cores there were large peaks of Si, Al, K, Mg, and Fe. Natural clay or mica-rich layers in the peat could easily account for these peaks. On the other hand, 16 rare earth elements produced results that indicated an anthropogenic source. For example, the elements europium, samarium, erbium, holmium, and uranium showed trends in cores four and five. Europium is used in nuclear control applications. Uranium is used as fuel for nuclear reactors; and erbium, samarium, and holmium are used in nuclear reactors. These elements concentrated most heavily in the 8-30 cm range. In core 4, and less prominently in core 5, an anomalous peak occurs near the 4-6 cm depth for all of these elements. Furthermore, cores 4 and 5 were closest to L-Lake and thus closer to the presumed source of groundwater contamination. These anomalous peaks tended to correlate vertically with changes in petrographic composition and depositional environments.