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Université de Neuchâtel

Evidence of Substantial Carbon Isotope Fractionation among Substrate, Inorganic Carbon, and Biomass during Aerobic Mineralization of 1,2-Dichloroethane by Xanthobacter autotrophicus

Hunkeler, Daniel ; Aravena, R

In: Applied and Environmental Microbiology, 2000, vol. 66, no. 11, p. 4870-4876

Carbon isotope fractionation during aerobic mineralization of 1,2-dichloroethane (1,2-DCA) by Xanthobacter autotrophicus GJ10 was investigated. A strong enrichment of 13C in residual 1,2-DCA was observed, with a mean fractionation factor α ± standard deviation of 0.968 ± 0.0013 to 0.973 ± 0.0015. In addition, a large carbon isotope fractionation between biomass and inorganic...

Université de Neuchâtel

Hydrogen and Carbon Isotope Fractionation during Aerobic Biodegradation of Benzene

Hunkeler, Daniel ; Andersen, N ; Aravena, R ; Bernasconi, M ; Butler, B.J

In: Environmental Science & Technology, 2001, vol. 35, no. 17, p. 3462-3467

The main aim of the study was to evaluate hydrogen and carbon isotope fractionation during biodegradation of benzene as a possible tool to trace the process in contaminated environments. Aerobic biodegradation of benzene by two bacterial isolates, Acinetobacter sp. and Burkholderia sp., was accompanied by significant hydrogen and carbon isotope fractionation with hydrogen isotope...

Université de Neuchâtel

Carbon and Chlorine Isotope Ratios of Chlorinated Ethenes Migrating through a Thick Unsaturated Zone of a Sandy Aquifer

Hunkeler, Daniel ; Aravena, R ; Shouakar-Stash, O ; Weisbrod, N ; Nasser, A ; Netzer, L ; Ronen, D

In: Environmental Science & Technology, 2011, vol. 45, p. 8247-8253

Compound-specific isotope analysis (CSIA) can potentially be used to relate vapor phase contamination by volatile organic compounds (VOCs) to their subsurface sources. This field and modeling study investigated how isotope ratios evolve during migration of gaseous chlorinated ethenes across a 18 m thick unsaturated zone of a sandy coastal plain aquifer. At the site, high concentrations of...

Université de Neuchâtel

Demonstrating a Natural Origin of Chloroform in Groundwater Using Stable Carbon Isotopes

Hunkeler, Daniel ; Laier, T ; Breider, Florian ; Jacobsen, O.S

In: Environmental Science & Technology, 2012, vol. 46, no. 11, p. 6096-6101

Chloroform has been for a long time considered only as an anthropogenic contaminant. The presence of chloroform in forest soil and groundwater has been widely demonstrated. The frequent detection of chloroform in groundwater in absence of other contaminants suggests that chloroform is likely produced naturally. Compound-specific isotope analysis of chloroform was performed on soil-gas and...

Université de Neuchâtel

Comments on “Analytical modelling of fringe and core biodegradation in groundwater plumes.” by Gutierrez-Neri et al. in J. Contam. Hydrol. 107: 1–9

Hunkeler, Daniel ; Höhener, P ; Atteia, O

In: Journal of Contaminant Hydrology, 2010, vol. 117, p. 1-6

In this comment, we revisit equations concerning the analytical solutions presented by Gutierrez-Neri and co-workers for reactive transport for a pollutant undergoing core and fringe degradations. We state that a correction needs to be made in Eq. (9) of the work of Gutierrez- Neri et al. in order that the equation follows closely previous work published by J. Bear (in 1-D) and P.A. Domenico (in...

Université de Neuchâtel

Assessing chlorinated ethene degradation in a large scale contaminant plume by dual carbon–chlorine isotope analysis and quantitative PCR

Hunkeler, Daniel ; Abe, Y ; Broholm, M.M ; Jeannottat, S ; Westergaard, C ; Jacobsen, C.S ; Aravena, R ; Bjerg, P.L

In: Journal of Contaminant Hydrology, 2011, vol. 119, p. 69-79

The fate of chlorinated ethenes in a large contaminant plume originating from a tetrachloroethene (PCE) source in a sandy aquifer in Denmark was investigated using novel methods including compound-specific carbon and chlorine isotope analysis and quantitative real-time polymerase chain reaction (qPCR) methods targeting Dehaloccocides sp. and vcrA genes. Redox conditions were...