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标题：Historical Changes in Polychlorinated Biphenyls Contaminated Sediments
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作者：Dang, Viet D. ; Walters, David M. ; Lee, Cindy M. 等
期刊名称：American Journal of Environmental Sciences
印刷版ISSN：1553-345X
出版年度：2012
卷号：8
期号：1
页码：11-15
DOI：10.3844/ajessp.2012.11.15
出版社：Science Publications
摘要：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.
关键词：Polychlorinated Biphenyls (PCBs); natural attenuation; Accelerated Solvent Extraction system (ASE); Fine Benthic Organic Matter (FBOM); Electron Capture Detector (ECD); National Priorities List (NPL); Food and Drug Administration (FDA)