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Hunkeler, Daniel

Nom
Hunkeler, Daniel
Affiliation principale
Fonction
Professeur.e ordinaire
Email
daniel.hunkeler@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/142
_
0000-0003-3525-9736

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  • Publication
    Accès libre
    Tracking chlorinated contaminants in the subsurface usingcompound-specific chlorine isotope analysis: A review of principles,current challenges and applications
    (2019-11)
    Zimmermann, Jeremy
    ;
    Halloran, Landon J.S. 
    ;
    Hunkeler, Daniel 
    Many chlorinated hydrocarbons have gained notoriety as persistent organic pollutants in the environ-ment. Engineered and natural remediation efforts require a monitoring tool to track the progress ofdegradation processes. Compound-specific isotope analysis (CSIA) is a robust method to evaluate theorigin and fate of contaminants in the environment and does not rely on concentration measurements.While carbon CSIA has established itself in the routine assessment of contaminated sites, studiesincorporating chlorine isotopes have only recently become more common. Although some aspects ofchlorine isotope analysis are more challenging than carbon isotope analysis, having additional isotopicdata yields valuable information for contaminated site management. This review provides an overview ofchlorine isotope fractionation of chlorinated contaminants in the subsurface by different processes andpresents analytical techniques and unresolved challenges in chlorine isotope analysis. A summary ofsuccessfulfield applications illustrates the potential of using chlorine isotope data. Finally, approaches inmodelling chlorine isotope fractionation due to degradation, diffusion, and sorption processes arediscussed.
  • Publication
    Accès libre
    Use of dual carbon-chlorine isotope analysis to assess the degradation pathways of 1,1,1-trichloroethane in groundwater
    (2016-2)
    Jamin, Pierre
    ;
    Vanhecke, Nicolas
    ;
    Badin, Alice 
    ;
    Haerens, Bruno
    ;
    Brouyère, Serge
    ;
    Hunkeler, Daniel 
    Compound-specific isotope analysis (CSIA) is a powerful tool to track contaminant fate in groundwater.However, the application of CSIA to chlorinated ethanes has received little attention so far. Thesecompounds are toxic and prevalent groundwater contaminants of environmental concern. The highsusceptibility of chlorinated ethanes like 1,1,1-trichloroethane (1,1,1-TCA) to be transformed via differentcompeting pathways (biotic and abiotic) complicates the assessment of their fate in the subsurface. Inthis study, the use of a dual CeCl isotope approach to identify the active degradation pathways of 1,1,1-TCA is evaluated for thefirst time in an aerobic aquifer impacted by 1,1,1-TCA and trichloroethylene (TCE)with concentrations of up to 20 mg/L and 3.4 mg/L, respectively. The reaction-specific dual carbonechlorine (CeCl) isotope trends determined in a recent laboratory study illustrated the potential of adual isotope approach to identify contaminant degradation pathways of 1,1,1-TCA. Compared to the dualisotope slopes (Dd13C/Dd37Cl) previously determined in the laboratory for dehydrohalogenation/hydro-lysis (DH/HY, 0.33±0.04) and oxidation by persulfate (∞), the slope determined fromfield samples(0.6±0.2, r2¼0.75) is closer to the one observed for DH/HY, pointing to DH/HY as the predominantdegradation pathway of 1,1,1-TCA in the aquifer. The observed deviation could be explained by a minorcontribution of additional degradation processes. This result, along with the little degradation of TCEdetermined from isotope measurements, confirmed that 1,1,1-TCA is the main source of the 1,1-dichlorethylene (1,1-DCE) detected in the aquifer with concentrations of up to 10 mg/L. This studydemonstrates that a dual CeCl isotope approach can strongly improve the qualitative and quantitativeassessment of 1,1,1-TCA degradation processes in the field.