TY  - JOUR
AU  - Dang, Viet D. 
AU  - Walters, David M. 
AU  - Lee, Cindy M. 
PY  - 2012
TI  - Historical Changes in Polychlorinated Biphenyls Contaminated Sediments
JF  - American Journal of Environmental Sciences
VL  - 8
IS  - 1
DO  - 10.3844/ajessp.2012.11.15
UR  - https://thescipub.com/abstract/ajessp.2012.11.15
AB  - Problem statement: PCBs contamination continues to pose a health risk to aquatic environments due to their recalcitrance and bioaccumulation. The Sangamo Weston/Twelvemile Creek/Lake Hartwell Superfund Site is an example of such a health risk as a result of PCBs discharged from a former capacitor manufacturing plant. We conducted a study in twelvemile creek (Clemson, SC, USA) to examine the temporal trend of PCB contaminated sediments. Approach: Surface sediments were sampled at four sites in fall 2008 to compare with concentrations measured in past studies. Total PCBs and congener-specific analyses were performed on Gas Chromatography-Electron Capture Detector (GC-ECD). Results: Total PCB concentrations ranged from 0.026-0.18 μg g-1, which were one order of magnitude lower than levels measured in 1987 (<0.20-10.23 μg g-1). Total PCBs in this study (based on more than 130 congeners) were similar to those observed in 2003-2004 (based on only 20 congeners). PCB congener patterns indicated that PCBs near the source were dominated by lower chlorinated congeners while heavy congeners were persistent further downstream. Conclusion: Physical and biochemical processes such as natural attenuation, mixing/dispersion and PCBs degradation are contributing to the decreasing concentrations after the discharge was eliminated in 1975. The congener pattern shift is likely attributed to a loss via volatilization and export of contaminated sediment from the stream. Burial could be a potential means to prevent resuspension into the water column.