title: Carbon and chlorine isotope fractionation during Fenton-like degradation of trichloroethene.
abstract: Dual isotope approach has been proposed as a viable tool for characterizing and assessing in situ contaminant transformation, however, little data is currently available on its applicability to chlorinated ethenes. This study determined carbon and chlorine isotope fractionation during Fenton-like degradation of trichloroethene (TCE). Carbon and chlorine isotope enrichment factors were εC=-2.9 ± 0.3‰ and εCl=-0.9 ± 0.1‰, respectively. An observed small secondary chlorine isotope effect (AKIECl=1.001) was consistent with an initial transformation by adding hydroxyl radicals (OH) to CC bonds without cleavage of CCl bonds. The relative change in carbon and chlorine isotope ratios (Δ=Δδ(13)C/Δδ(37)Cl) was calculated to be 3.1 ± 0.2, approximately equal to the ratio of chlorine and carbon isotope enrichment factors (εC/εCl=3.2). The similarity of the Δ (or εC/εCl) values between Fenton-like degradation and microbial reductive dechlorination of TCE was observed, indicating that application of solely dual isotope approach may be limited in distinguishing the two transformation pathways.
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China; School of Environmental Studies, China University of Geosciences, Wuhan 430074, China. Electronic address: lydcn84@126.com.
authors.forename: Yunde
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China; School of Environmental Studies, China University of Geosciences, Wuhan 430074, China. Electronic address: yiqungan@cug.edu.cn.
authors.forename: Yiqun
authors.initials: Y
authors.lastname: Gan
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China; School of Environmental Studies, China University of Geosciences, Wuhan 430074, China. Electronic address: aiguozhou0516@126.com.
authors.forename: Aiguo
authors.initials: A
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China. Electronic address: 04204111@163.com.
authors.forename: Cunfu
authors.initials: C
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China; School of Environmental Studies, China University of Geosciences, Wuhan 430074, China. Electronic address: lixiaoqian2007@gmail.com.
authors.forename: Xiaoqian
authors.initials: X
authors.lastname: Li
authors.affiliation: State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China; School of Environmental Studies, China University of Geosciences, Wuhan 430074, China. Electronic address: cugytt@gmail.com.
authors.forename: Tingting
authors.initials: T
authors.lastname: Yu
mesh_terms: D002247:Carbon Isotopes / Q000737:chemistry / Q000302:isolation & purification; D005591:Chemical Fractionation / Q000379:methods*; D002713:Chlorine / Q000737:chemistry* / Q000302:isolation & purification*; D004785:Environmental Pollutants / Q000737:chemistry* / Q000302:isolation & purification*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D007700:Kinetics; D014241:Trichloroethylene / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D002247:Carbon Isotopes; D004785:Environmental Pollutants; C045076:Fenton's reagent; D014241:Trichloroethylene; D002713:Chlorine; D006861:Hydrogen Peroxide; D007501:Iron
keywords: Carbon isotope fractionation; Chlorine isotope fractionation; Fenton-like reaction; Trichloroethene