title: Distinct Dual C-Cl Isotope Fractionation Patterns during Anaerobic Biodegradation of 1,2-Dichloroethane: Potential To Characterize Microbial Degradation in the Field.
abstract: This study investigates, for the first time, dual C-Cl isotope fractionation during anaerobic biodegradation of 1,2-dichloroethane (1,2-DCA) via dihaloelimination by Dehalococcoides and Dehalogenimonas-containing enrichment cultures. Isotopic fractionation of 1,2-DCA (εbulkCand εbulkCl) for Dehalococcoides (-33.0 ± 0.4‰ and -5.1 ± 0.1‰) and Dehalogenimonas-containing microcosms (-23 ± 2‰ and -12.0 ± 0.8‰) resulted in distinctly different dual element C-Cl isotope correlations (Λ = Δδ13C/Δδ37Cl ≈ εbulkC/εbulkCl), 6.8 ± 0.2 and 1.89 ± 0.02, respectively. Determined isotope effects and detected products suggest that the difference on the obtained Λ values for biodihaloelimination could be associated with a different mode of concerted bond cleavage rather than two different reaction pathways (i.e., stepwise vs concerted). Λ values of 1,2-DCA were, for the first time, determined in two field sites under reducing conditions (2.1 ± 0.1 and 2.2 ± 2.9). They were similar to the one obtained for the Dehalogenimonas-containing microcosms (1.89 ± 0.02) and very different from those reported for aerobic degradation pathways in a previous laboratory study (7.6 ± 0.1 and 0.78 ± 0.03). Thus, this study illustrates the potential of a dual isotope analysis to differentiate between aerobic and anaerobic biodegradation pathways of 1,2-DCA in the field and suggests that this approach might also be used to characterize dihaloelimination of 1,2-DCA by different bacteria, which needs to be confirmed in future studies.
authors.affiliation: Centre for Hydrogeology and Geothermics, University of Neuchâtel , 2000 Neuchâtel, Switzerland.|Grup de Mineralogia Aplicada i Geoquímica de Fluids, Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Geologia, Universitat de Barcelona , Martí i Franquès s/n, 08028 Barcelona, Spain.|Institute of Environmental Assessment and Water Research (IDAEA), CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain; Associated Unit: Hydrogeology Group (UPC-CSIC), Barcelona, Spain.
authors.forename: J
authors.identifier: 0000-0001-9492-7306
authors.initials: J
authors.lastname: Palau
authors.affiliation: Department of Environmental Engineering and Earth Sciences, Clemson University , Clemson, South Carolina United States.
authors.forename: R
authors.initials: R
authors.lastname: Yu
authors.affiliation: Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona , Carrer de les Sitges s/n, 08193 Bellaterra, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Hatijah Mortan
authors.affiliation: Department of Earth and Environmental Sciences, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada.|Isotope Tracer Technologies Inc., Waterloo, Ontario Canada N2 V 1Z5.
authors.forename: O
authors.initials: O
authors.lastname: Shouakar-Stash
authors.affiliation: Grup de Mineralogia Aplicada i Geoquímica de Fluids, Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Geologia, Universitat de Barcelona , Martí i Franquès s/n, 08028 Barcelona, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Rosell
authors.affiliation: Department of Environmental Engineering and Earth Sciences, Clemson University , Clemson, South Carolina United States.
authors.forename: D L
authors.identifier: 0000-0001-6778-3706
authors.initials: DL
authors.lastname: Freedman
authors.affiliation: Department of Earth Sciences, "Sapienza" University , P.le A. Moro 5, 00185 Rome, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Sbarbati
authors.affiliation: Remediation Engineering and Technology, BP America, Houston, Texas 77079, United States.
authors.forename: S
authors.initials: S
authors.lastname: Fiorenza
authors.affiliation: Department of Earth and Environmental Sciences, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Aravena
authors.affiliation: Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona , Carrer de les Sitges s/n, 08193 Bellaterra, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Marco-Urrea
authors.affiliation: Helmholtz Zentrum München, German Research Center for Environmental Health, D-85764 Neuherberg, Germany.
authors.forename: M
authors.identifier: 0000-0003-4746-9052
authors.initials: M
authors.lastname: Elsner
authors.affiliation: Grup de Mineralogia Aplicada i Geoquímica de Fluids, Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Geologia, Universitat de Barcelona , Martí i Franquès s/n, 08028 Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Soler
authors.affiliation: Centre for Hydrogeology and Geothermics, University of Neuchâtel , 2000 Neuchâtel, Switzerland.
authors.forename: D
authors.initials: D
authors.lastname: Hunkeler
mesh_terms: D001673:Biodegradation, Environmental; D002247:Carbon Isotopes; D005591:Chemical Fractionation; D041862:Chloroflexi / Q000378:metabolism; D007700:Kinetics
chemical_list: D002247:Carbon Isotopes