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Hunkeler, Daniel

Nom
Hunkeler, Daniel
Affiliation principale
Fonction
Professeur ordinaire
Email
daniel.hunkeler@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/142

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  • Publication
    Métadonnées seulement
    Evidence for in situ degradation of mono-and polyaromatic hydrocarbons in alluvial sediments based on microcosm experiments with 13C-labeled contaminants
    (2007-4-29)
    Morasch, Barbara
    ;
    Höhener, Patrick
    ;
    Hunkeler, Daniel 
    A microcosm study was conducted to investigate the degradation of mono- and polyaromatic hydrocarbons under in situ-like conditions using alluvial sediments from the site of a former cokery. Benzene, naphthalene, or acenaphthene were added to the sediments as C-13-labeled substrates. Based on the evolution of C-13-CO2 determined by gas chromatography isotope-ratio mass spectrometry (GC-IRMS) it was possible to prove mineralization of the compound of interest in the presence of other unknown organic substances of the sediment material. This new approach was suitable to give evidence for the intrinsic biodegradation of benzene, naphthalene, and acenaphthene under oxic and also under anoxic conditions, due to the high sensitivity and reproducibility of C-13/C-12 stable isotope analysis. This semi-quantitative method can be used to screen for biodegradation of any slowly degrading, strongly sorbing compound in long-term experiments. (c) 2007 Elsevier Ltd. All rights reserved.
  • Publication
    Métadonnées seulement
    Isotopic and geochemical assessment of in situ biodegradation of chlorinated hydrocarbons
    (2003)
    Kirtland, Brian
    ;
    Aelion, Marjorie
    ;
    Stone, Peter
    ;
    Hunkeler, Daniel 
    Currently there is no in situ method to detect and quantify complete mineralization of chlorinated hydrocarbons (CHCs) to CO2. Combined isotopic measurements in conjunction with traditional chemical techniques were used to assess in situ biodegradation of trichloroethylene (TCE) and carbon tetrachloride (CT). Vadose zone CHC, ethene, ethane, methane, O-2, and CO2 concentrations were analyzed using gas chromatography over 114 days at the Savannah River Site. delta(13)C of CHC and delta(13) C and C-14 of vadose zone CO2, sediment organic matter, and groundwater dissolved inorganic carbon (DIC) were measured. Intermediate metabolites of TCE and CT accounted for less than or equal to10% of total CHCs. delta(13)C of cis-1,2-dichloroethylene (DCE) was always heavier than TCE indicating substantial DCE biodegradation. C-14-CO2 values ranged from 84 to 128 percent modern carbon (pMC), suggesting that plant root-respired CO2 was dominant. C-14-CO2 values decreased over time (up to 12 pMC), and contaminated groundwater C-14-DIC (76 pMC) was substantially depleted relative to the control (121 pMC). C-14 provided a direct measure of complete CHC mineralization in vadose zone and groundwater in situ and may improve remediation strategies.