title: Invariant chlorine isotopic signatures during microbial PCB reductive dechlorination.
abstract: In order to develop more robust insight into the natural attenuation of polychlorinated biphenyls (PCBs), the chlorine isotopic composition of residual 2,3,4,5-tetrachlorobiphenyl (2,3,4,5-CB) was monitored as it underwent microbial reductive dechlorination to 2,3,5-trichlorobiphenyl (2,3,5-CB) in laboratory cultures. Reverse-phase high performance liquid chromatography (HPLC) was employed to isolate the former compound from the experimental matrix for delta37Cl measurement. No detectable isotopic fractionation was observed over the 90 day incubation with sterile control, standard, and inoculated samples all exhibiting delta37Cl values with a range of approximately 0.5 per thousand. These results show that this type of biological activity can be discriminated from other transformations by the absence of a measurable isotope effect during microbial reductive dechlorination. The utility of HPLC isolation for compound-specific delta37Cl analyses of environmentally relevant species is also demonstrated.
authors.affiliation: Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA. ndrenzek@whoi.edu
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Drenzek
authors.forename: Timothy I
authors.initials: TI
authors.lastname: Eglinton
authors.forename: Carl O
authors.initials: CO
authors.lastname: Wirsen
authors.forename: Neil C
authors.initials: NC
authors.lastname: Sturchio
authors.forename: Linnea J
authors.initials: LJ
authors.lastname: Heraty
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Sowers
authors.forename: Qingzhong
authors.initials: Q
authors.lastname: Wu
authors.forename: Harold D
authors.initials: HD
authors.lastname: May
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Reddy
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D001711:Biotransformation; D002713:Chlorine / Q000032:analysis* / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004785:Environmental Pollutants / Q000032:analysis / Q000378:metabolism*; D007554:Isotopes; D010084:Oxidation-Reduction; D011078:Polychlorinated Biphenyls / Q000032:analysis / Q000378:metabolism*
chemical_list: D004785:Environmental Pollutants; D007554:Isotopes; D002713:Chlorine; D011078:Polychlorinated Biphenyls