Changes in Enantiomeric Fractions during Microbial Reductive Dechlorination of PCB132, PCB149, and Aroclor 1254 in Lake Hartwell Sediment Microcosms

Pakdeesusuk, Usarat; Jones, William J.; Lee, Cindy M.; Garrison, Arthur W.; O'Niell, W. L.; Freedman, David L.; Coates, John T.; Wong, Charles S.

doi:10.1021/es026039g

Cited by 46 publications

(59 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The latter congeners exist as stable enantiomers, and we wondered whether their dechlorination would be limited. Stereoisomers of PCBs exist as racemic mixtures in commercial PCBs, and evidence for stereoselective dechlorination of some PCB congeners has been reported (52,67). Our data show that there was well over 50% dechlorination of 236-236-CB, 236-245-CB, 2356-245-CB, and 2345-236-CB, demonstrating that both stereoisomers of each of these congeners are dechlorinated.…”

Section: Discussionsupporting

confidence: 56%

Development and Characterization of Stable Sediment-Free Anaerobic Bacterial Enrichment Cultures That Dechlorinate Aroclor 1260

Bedard

Bailey

Reiss

et al. 2006

Appl Environ Microbiol

View full text Add to dashboard Cite

We have developed sediment-free anaerobic enrichment cultures that dechlorinate a broad spectrum of highly chlorinated polychlorinated biphenyls (PCBs). The cultures were developed from Aroclor 1260-contaminated sediment from the Housatonic River in Lenox, MA. Sediment slurries were primed with 2,6-dibromobiphenyl to stimulate Process N dechlorination (primarily meta dechlorination), and sediment was gradually removed by successive transfers (10%) to minimal medium. The cultures grow on pyruvate, butyrate, or acetate plus H 2 . Gas chromatography-electron capture detector analysis demonstrated that the cultures extensively dechlorinate 50 to 500 g/ml of Aroclor 1260 at 22 to 24°C by Dechlorination Process N. Triplicate cultures of the eighth transfer without sediment dechlorinated 76% of the hexa-through nonachlorobiphenyls in Aroclor 1260 (250 g/ml) to tri-through pentachlorobiphenyls in 110 days. At least 64 PCB congeners, all of which are chlorinated on both rings and 47 of which have six or more chlorines, were substrates for this dechlorination. To characterize the bacterial diversity in the enrichments, we used eubacterial primers to amplify and clone 16S rRNA genes from DNA extracted from cultures grown on acetate plus H 2 . Restriction fragment length polymorphism analysis of 107 clones demonstrated the presence of Thauera-like Betaproteobacteria, Geobacterlike Deltaproteobacteria, Pseudomonas species, various Clostridiales, Bacteroidetes, Dehalococcoides of the Chloroflexi group, and unclassified Eubacteria. Our development of highly enriched, robust, stable, sediment-free cultures that extensively dechlorinate a highly chlorinated commercial PCB mixture is a major and unprecedented breakthrough in the field. It will enable intensive study of the organisms and genes responsible for a major PCB dechlorination process that occurs in the environment and could also lead to effective remediation applications.Polychlorinated biphenyls (PCBs) are priority pollutants that were used worldwide for a variety of applications for more than 50 years. PCB molecules are composed of a biphenyl backbone substituted with 1 to 10 chlorines. They were manufactured by catalytic chlorination of biphenyl to obtain specified weight percentages of chlorine for different applications. Consequently, they are complex mixtures, each composed of 60 to 90 PCB congeners. In the United States PCBs were produced under the trade name Aroclor. Several hundred million pounds of PCBs were released into the environment and pollute many rivers, lakes, and harbors worldwide. These PCBs persist in the sediments, accumulate in biota, and biomagnify in the food chain. Multiple adverse health effects have been attributed to them, and they are suspected human carcinogens (62). Microbial reductive PCB dechlorination provides a natural means of detoxifying PCBs in aquatic sediments because it reduces their persistence and increases their biodegradability and metabolism by other prokaryotes and by higher organisms (14,16,50,51,55).There have been numer...

show abstract

Section: Discussionsupporting

confidence: 56%

Development and Characterization of Stable Sediment-Free Anaerobic Bacterial Enrichment Cultures That Dechlorinate Aroclor 1260

Bedard

Bailey

Reiss

et al. 2006

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

“…Microcosms with sediments from the same cores [156] spiked with racemic PCB 132 reductively meta-dechlorinated this congener nonenantioselectively to PCB 91, which in turn was stereoselectively metadechlorinated to achiral PCB 51 ( Figure 4.12). Similarly, PCB 149 was nonstereoselectively para-dechlorinated to PCB 95, in turn enantioselectively meta-dechlorinated to achiral PCB 53 [163]. The enantiomer preferences for PCB 149 dechlorination were consistent between the laboratory microcosms [163] and field observations, suggesting possible similarities in the microbial consortia in both cases.…”

Section: Pcbssupporting

confidence: 51%

“…Similarly, PCB 149 was nonstereoselectively para-dechlorinated to PCB 95, in turn enantioselectively meta-dechlorinated to achiral PCB 53 [163]. The enantiomer preferences for PCB 149 dechlorination were consistent between the laboratory microcosms [163] and field observations, suggesting possible similarities in the microbial consortia in both cases. However, PCB 132 was nonracemic in the cores [156], suggesting that either the microbial consortia and/or environmental conditions affecting microbial activity were different between the laboratory and in situ.…”

Section: Pcbssupporting

confidence: 51%

“…Anaerobic reductive dechlorination of chiral PCBs confirmed that microbial reductive dechlorination in situ was possible in Lake Hartwell [163]. Microcosms with sediments from the same cores [156] spiked with racemic PCB 132 reductively meta-dechlorinated this congener nonenantioselectively to PCB 91, which in turn was stereoselectively metadechlorinated to achiral PCB 51 ( Figure 4.12).…”

Section: Pcbsmentioning

confidence: 79%

See 1 more Smart Citation

Chirality as an Environmental Forensics Tool

Wong

Warner

2009

Persistent Organic Pollutants

Self Cite

View full text Add to dashboard Cite

“…Singer et al [36] found that PCB 95 was less likely to undergo aerobic biotransformation than PCB 91 with pure cultures under ideal laboratory conditions. Previous work with microcosms incubated with sediment from Lake Hartwell indicated that both chiral congeners could undergo anaerobic biotransformation [37]. On the other hand, similarity in EF values in the PEs among the sites does not provide any strong evidence to indicate additional inputs of PCB to the system.…”

Section: Chiral Signaturesmentioning

confidence: 73%

Assessing ongoing sources of dissolved-phase polychlorinated biphenyls in a contaminated stream

Dang

Walters

Lee

2012

Environmental Toxicology and Chemistry

Self Cite

View full text Add to dashboard Cite

Abstract-Few studies assess the potential of ongoing sources of ''fresh'' polychlorinated biphenyls (PCBs) to aquatic systems when direct discharge to the environment has been eliminated. In the present study, the authors used single-layered, low-density polyethylene samplers (PEs) to measure total PCB concentrations, congener profiles, and enantiomeric fractions (EFs) in a contaminated stream and to provide multiple lines of evidence for assessing ongoing inputs of PCB. Concentrations were well above background levels that have been monitored for years. Concentrations significantly increased with distance, the farthest downstream PE concentrations being almost five times greater than those at 79 m downstream of a historical point source. The PCBs in the PEs at 79 m downstream of the contamination source were dominated by low K OW congeners, similar to those in the mixture of Aroclors 1016 and 1254 (4:1 v/v) historically released from the former capacitor manufacturer. The only two chiral congeners detected in the PEs downstream were PCBs 91 and 95. The EF values were nonracemic for PCB 91, while the values were either racemic or near racemic for PCB 95. Increased PCB concentrations with distance and a congener composition of predominantly low-weight congeners in the PEs at 79 m downstream of the plant site suggested an ongoing PCB source from the plant site. Chiral signatures suggested aerobic biotransformation of dissolved PCBs but did not shed any light on possible ongoing PCB inputs. Environ. Toxicol. Chem. 2013;32:535-540. # 2012 SETAC

show abstract

Changes in Enantiomeric Fractions during Microbial Reductive Dechlorination of PCB132, PCB149, and Aroclor 1254 in Lake Hartwell Sediment Microcosms

Cited by 46 publications

References 38 publications

Development and Characterization of Stable Sediment-Free Anaerobic Bacterial Enrichment Cultures That Dechlorinate Aroclor 1260

Development and Characterization of Stable Sediment-Free Anaerobic Bacterial Enrichment Cultures That Dechlorinate Aroclor 1260

Chirality as an Environmental Forensics Tool

Assessing ongoing sources of dissolved-phase polychlorinated biphenyls in a contaminated stream

Contact Info

Product

Resources

About