Enhanced Reductive Dechlorination of Polychlorinated Biphenyl Impacted Sediment by Bioaugmentation with a Dehalorespiring Bacterium

Abstract

Anaerobic reductive dehalogenation of commercial PCBs such as Aroclor 1260 has a critical role of transforming highly chlorinated congeners to less chlorinated congeners that are then susceptible to aerobic degradation. The efficacy of bioaugmentation with the dehalorespiring bacterium “Dehalobium chlorocoercia” DF1 was tested in 2-liter laboratory mesocosms containing sediment contaminated with weathered Aroclor 1260 (1.3 ppm) from Baltimore Harbor, MD. Total penta- and higher chlorinated PCBs decreased by approximately 56% (by mass) in bioaugmented mesocosms after 120 days compared with no activity observed in unamended controls. Bioaugmentation with DF-1 enhanced the dechlorination of doubly flanked chlorines and stimulated the dechlorination of single flanked chlorines as a result of an apparent synergistic effect on the indigenous population. Addition of granulated activated carbon had a slight stimulatory effect indicating that anaerobic reductive dechlorination of PCBs at low concentrations was not inhibited by a high background of inorganic carbon that could affect bioavailability. The total number of dehalorespiring bacteria was reduced by approximately half after 60 days. However, a steady state level was maintained that was greater than the indigenous population of putative dehalorespiring bacteria in untreated sediments and DF1 was maintained within the indigenous population after 120 days. The results of this study demonstrate that bioaugmentation with dehalorespiring bacteria has a stimulatory effect on the dechlorination of weathered PCBs and supports the feasibility of using in situ bioaugmentation as an environmentally less invasive and lower cost alternate to dredging for treatment of PCB impacted sediments.

Use of lipid biomarkers for identification of regional sources and dechlorination characteristics of polychlorinated biphenyls in the East China Sea

“…The dechlorination process typically removes the meta-and para-chlorines (Abramowicz, 1990). With such structural characteristics, the dechlorination pathway of the parent compound PCB180 that degraded to PCB153, PCB101, and PCB52 under anaerobic conditions was inferred in a recent study (Payne et al, 2011). Here, we chose the ratios of PCB52/PCB180 (ratio I), PCB101/PCB180 (ratio II), and PCB153/PCB180 (ratio III) (Table S5) (Li et al, 2002(Wei et al, 2007, 2006 relationship.…”

Anaerobic degradation of Polychlorinated Biphenyls (PCBs) and Polychlorinated Biphenyls Ethers (PBDEs), and microbial community dynamics of electronic waste-contaminated soil

“…Aerobic and anaerobic biodegradation of such compounds have been investigated extensively (Bedard, 2003;Chang et al, 2013;Chen et al, 2010;Cutter et al, 2001;Dabrowska and Rosinska, 2012;Deng et al, 2011;Fennell et al, 2004;Li et al, 2005;Payne et al, 2011Payne et al, , 2013Rayne et al, 2003;Shih et al, 2012). Aerobic microbial degradation is often possible only when halogenated compounds have a maximum of four-to-five halogen atoms, although an aerobic bacterium responsible for deca-BDE debromination was isolated from sediment (Deng et al, 2011).…”

Impacts of PCB analytical interpretation uncertainties on dechlorination assessment and remedial decisions

“…For example, Quensen et al (1990) assume co-eluting congeners occur in equal proportions, but also consider extreme concentrations in which peaks represent a single congener. Two decades later, a similar approach to splitting peaks persists: for example, Payne et al (2011) equally split the mass of co-eluting congeners for the purpose of calculating surrogate variables. Frame (1995Frame ( , 1997a were among the first to split co-eluting peaks based on the average distribution of congeners in Aroclor mixtures.…”