Polychlorinated biphenyls in the surficial sediment of Indiana Harbor and Ship Canal, Lake Michigan
ABSTRACT We report the results of the first intensive survey of polychlorinated biphenyls (PCBs) in the surficial sediment of the Indiana Harbor and Ship Canal (IHSC) in East Chicago, Indiana, a part of the Calumet River tributary of Lake Michigan that will be dredged to maintain depth for ship traffic. The tributary has previously been reported to be a large source of PCBs to Lake Michigan. PCB congeners were measured using tandem mass spectrometry in multiple reaction monitoring mode, a method that provides a high level selectivity and sensitivity for PCBs in complex environmental samples. The PCB concentrations (sum of 163 congeners or coeluting peaks) range from 53 to 35,000 ng g− 1 dry weight (d.w.) and are comparable to other PCB concentrations at contaminated tributaries in the United States, most of them (although not IHSC) established by law as Superfund sites. The PCB congener signal strongly resembles the original technical mixture Aroclor 1248 that has experienced a small amount of weathering — less than 2.5% by mass for the statistically different congeners — consistent with desorption, volatilization, and microbial dechlorination. The origin of the PCBs in IHSC is not known but Aroclor 1248 was used in hydraulic fluids, vacuum pumps, plasticizers and adhesives. Possible uses of this mixture in East Chicago included the equipment and auxiliary services for the adjacent steel mill and gas refinery and/or lubrication for the drawbridges spanning the canal.
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ABSTRACT: The U.S. Department of Energy Portsmouth Gaseous Diffusion Plant is in the early stages of decommissioning and decontamination. During operations, the site drew a large amount of electric power and had multiple large switchyards on site. These are a source of polychlorinated biphenyls (PCB) contamination to both on-site and off-site streams. Some soil remediation has been completed in the main switchyard. During 2011 and 2012, fifteen sites were sampled at the surface (<10 cm) and subsurface (20–30 cm) to characterize the extent of PCB contamination, to identify weathering and migration of PCB contamination and to explore potential polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) contamination due to transformer fires and explosions in the 1950s and 1960s. Stagnant sites tended to exhibit more migration of contamination to deeper sediments than sites with fast-moving waters, and the highest concentrations were found at the bottom of a settling pond. A signature set of five dioxin-like PCBs were consistently found across the site with higher concentrations in carbon rich surface sediments. PCB concentrations had a significant inverse correlation with clay content, suggesting that PCBs did not bind to clays at this site. Remediation has reduced PCB concentrations throughout the site compared to levels found in previous studies and long-term upkeep of sediment lagoons is necessary to retain PCB and dioxin-rich sediments. The flow regimen, organic carbon and clay content play a very important role in the fate of PCBs in the environment at the surface as well as downward migration.Chemosphere 11/2014; 114:93–100. DOI:10.1016/j.chemosphere.2014.03.092 · 3.50 Impact Factor
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ABSTRACT: Polychlorinated biphenyls (PCBs) are carcinogenic, persistent, and bioaccumulative contaminants that pose risks to human and environmental health. In this study, we evaluated the PCB biodegradation of sediments from Indiana Harbor and Ship Canal (IHSC), a PCB-contaminated site (average PCB concentration = 12,570 ng/g dw). PCB congener profiles and bacterial community structure in a core sediment sample (4.57 m long) were characterized. Analysis of vertical PCB congener profile patterns in sediment and pore water strongly suggests that in situ dechlorination occurred in sediments. However, 16S rRNA genes from putative PCB-dechlorinating Chloroflexi were relatively more abundant in upper 2 m sediments, as were genes indicative of aerobic biodegradation potential (i.e. biphenyl dioxygenase (bphA)). Characterization of the bacterial community by terminal restriction fragment length polymorphism and comparison of these with sediment and pore water PCB congener profiles with the Mantel test revealed a statistical correlation (p < 0.001). Sequences classified as Acinetobacter and Acidovorax were highly abundant in deep sediments. Overall, our results suggest that PCB dechlorination has already occurred, and that IHSC sediments have the potential for further aerobic and anaerobic PCB biodegradation.International Biodeterioration & Biodegradation 04/2014; 89:50–57. DOI:10.1016/j.ibiod.2014.01.005 · 2.24 Impact Factor
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ABSTRACT: Polychlorinated biphenyls (PCBs) are anthropogenic substances that have been detected in many parts of the environment and can have major negative impacts on ecosystem and human health. A documented release of PCBs from a nylon plant occurred in 1969 on the Escambia River just upstream of the Escambia Bay estuary along the north coast of the Gulf of Mexico. Other unreported releases of PCBs also likely occurred in the river and bay. The present study sampled sediments in the river and bay and assessed the predominant parent Aroclor of PCBs, and the changes in congener profile and toxic equivalents (TEQ) since the release. United States Environmental Protection Agency (US EPA) method 1668A, which provides quantitative data for 168 elutions, was employed for the analysis according to National Environmental Laboratory Accreditation Program procedures. Correlation analysis and principal component analysis of the PCB congener profiles for the sediments and Aroclors showed that the sedimentary PCB congeners are most similar to that of early production Aroclor 1254 made prior to 1971. Chronologically the use of the early production Aroclor 1254 corresponds to the time of the release. Since the release, overall chlorination of the sedimentary PCBs has decreased by 3% as a result of a shift in chlorination homolog profile to lesser-chlorinated congeners that presumably originated from dechlorination of Aroclor PCBs and from non-Aroclor source(s) of PCB 11, a dichlorobiphenyl. Despite a likely overall decrease in the quantity of dioxin-like PCBs, the TEQ/mole of sediment PCBs, did not substantially change because of a highly toxic congener (PCB 126) that was present at trace amounts in the sediments. There was a modest increase in lesser-chlorinated O,P-congeners that are suspected to have some toxicity to mammals. These findings have relevance for the evolution of environmental PCBs, which has not been studied in this system.Environmental Forensics 06/2012; 13(2):164-174. DOI:10.1080/15275922.2012.676595 · 0.73 Impact Factor