title: Enantiomeric composition of chiral polychlorinated biphenyl atropisomers in aquatic bed sediment.
abstract: Enantiomeric ratios (ERs) for eight polychlorinated biphenyl (PCB) atropisomers were measured in aquatic sediment from selected sites throughout the United States by using chiral gas chromatography/mass spectrometry. Nonracemic ERs for PCBs 91, 95, 132, 136, 149, 174, and 176 were found in sediment cores from Lake Hartwell, SC, which confirmed previous inconclusive reports of reductive dechlorination of PCBs at these sites on the basis of achiral measurements. Nonracemic ERs for many of the atropisomers were also found in bed-sediment samples from the Hudson and Housatonic Rivers, thus indicating that some of the PCB biotransformation processes identified at these sites are enantioselective. Patterns in ERs among congeners were consistent with known reductive dechlorination patterns at both river sediment basins. The enantioselectivity of PCB 91 is reversed between the Hudson and Housatonic River sites, which implies that the two sites have different PCB biotransformation processes with different enantiomer preferences.
authors.affiliation: Ecosystems Research Division, National Exposure Research Laboratory, U.S. Environmental Protection Agency, Athens, Georgia 30605, USA.
authors.forename: C S
authors.initials: CS
authors.lastname: Wong
authors.forename: A W
authors.initials: AW
authors.lastname: Garrison
authors.forename: W T
authors.initials: WT
authors.lastname: Foreman
mesh_terms: D001711:Biotransformation; D005618:Fresh Water / Q000032:analysis / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D019015:Geologic Sediments / Q000032:analysis*; D011078:Polychlorinated Biphenyls / Q000032:analysis* / Q000737:chemistry* / Q000378:metabolism; D013237:Stereoisomerism; D014481:United States; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism
chemical_list: D014874:Water Pollutants, Chemical; D011078:Polychlorinated Biphenyls