MERCURY CONCENTRATIONS IN SURFACE SEDIMENTS FROM THE MOUTH OF THE SAVANNAH RIVER, GEORGIA

Mercury contamination is a major problem that can affect the aquatic environment as well as human health. The Savannah River receives 5,025,161 lbs of toxic effluents per year, making it the third most polluted river in the United States (Gayer, 2014). The port of Savannah hosts many paper, fertilizer, and chemical factories. Contaminants produced by industrial plants and ships are released into the river and often cause polluting substances to accumulate in the sediments. These processes affect the level of toxic exposure to biota in the sediments and the water column. Therefore, the purpose of this study was to determine mercury concentrations in surface sediments from the mouth of the Savannah River, Georgia prior to the Savannah Harbor Expansion Project (SHEP). Surface sediments were collected using a Ponar grab from 10 stations along the estuarine portion of the Savannah River. A total of 3 grabs were collected at each station: left bank, right bank, and main channel. Mean grain size and total organic carbon were determined. Sediment samples were analyzed for mercury using EPA Method 7473 on a Direct Mercury Analyzer (DMA-80). Sediment and mean grain sizes ranged from silts and clays (18.1443±0.2186 µm) to very coarse sands (760.9436±148.6733 µm). Mercury concentrations ranged from 0.0059±0.0040 ppm to 0.1485±0.1332 ppm. The average mercury concentration for the Savannah River was 0.0525±0.0156 ppm, which is below ERL levels (Long et al., 1995). There was significant interaction between mean grain size and station on total mercury concentrations (p < .0001). The highest mercury concentrations were found within finer sediments. Knowing the total mercury concentration status within surface sediments could serve as baseline data prior to channel dredging. It could also help provide means to develop ways to manage pollution sources and the release of toxic effluents into aquatic environments.