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Isotope fractionation of volatile organic contaminants in porous media under unsaturated conditions: Mechanisms and applications

English title Isotope fractionation of volatile organic contaminants in porous media under unsaturated conditions: Mechanisms and applications
Applicant Hunkeler Daniel
Number 121932
Funding scheme Project funding (Div. I-III)
Research institution Centre d'hydrogéologie et de géothermie Université de Neuchâtel
Institution of higher education University of Neuchatel - NE
Main discipline Other disciplines of Environmental Sciences
Start/End 01.11.2008 - 31.10.2011
Approved amount 208'698.00
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Keywords (4)

Stable isotopes; organic contaminants; unsaturated zone; biodegradation

Lay Summary (English)

Lead
Lay summary
Organic compounds such as chlorinated compounds and petroleum hydrocarbons are among the most common groundwater contaminants. For risk assessment and in order to plan effective remediation methods, it is important to know from where these contaminants originate and to what extent they are removed by naturally occurring biodegradation. A recently proposed approach to gain insight into the origin and fate of organic compounds in groundwater is the use of stable isotope analysis. Organic contaminants from different sources (e.g. spills caused by different companies) often have a different isotopic composition. In other words, the naturally occurring stable isotopes (e.g. 13C and 12C) are present in different proportions. Furthermore, during biodegradation frequently the heavy isotopes become more and more abundant in the contaminant because molecules with light isotope are degraded faster by bacteria. This isotope enrichment trend makes it possible to identify and quantify biodegradation. The stable isotope method has so far mainly been investigated and applied in groundwater studies. In contrast little information is available so far on its use in the unsaturated zone between the water table and the land surface. The main aim of the project is to investigate whether the stable isotope method can also be used in unsaturated zone studies to link contaminants detected at the surface to subsurface sources and to demonstrate biodegradation. The project focuses on volatile organic compounds because these compounds diffuse rapidly through the unsaturated zone and hence can contaminate groundwater or impact air quality in buildings. Before the isotope method can be applied to solve practical questions, more knowledge is necessary on how isotope ratios evolve during transport and degradation of organic compounds under unsaturated conditions. The effect of these processes on isotope ratios will be investigated in laboratory column experiments. Such experiments have the advantage that key experimental parameters can be controlled exactly and mathematical approaches to quantify the phenomena tested rigorously. In addition, several field sites will be equipped with multilevel gas samplers and it will be investigated whether isotope ratios can be used to link contaminants to their source and/or to demonstrate biodegradation.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Name Institute

Publications

Publication
Can soil gas VOCs be related to groundwater plumes based on their isotope signature?
Jeannottat Simon, Hunkeler Daniel (2013), Can soil gas VOCs be related to groundwater plumes based on their isotope signature?, in Environmental Science & Technology, 47(21), 12115-12122.
Chlorine and carbon isotope fractionation during volatilization and diffusive transport of trichloroethene in the unsaturated zone
Jeannottat Simon, Hunkeler Daniel (2012), Chlorine and carbon isotope fractionation during volatilization and diffusive transport of trichloroethene in the unsaturated zone, in Environmental Science and Technology, 46, 3169-3176.
Assessing chlorinated ethene degradation in a large scale contaminant plume by dual carbon-chlorine isotope analysis and quantitative PCR.
Hunkeler Daniel, Abe Yumiko, Broholm Mette M., Jeannottat Simon, Westergaard Claus, Suhr Jacobsen Carsten, Aravena Ramon, Bjerg Poul L. (2011), Assessing chlorinated ethene degradation in a large scale contaminant plume by dual carbon-chlorine isotope analysis and quantitative PCR., in Journal of Contaminant Hydrology, 119(1-4), 69-79.
Carbon and chlorine isotope ratios of chlorinated ethenes migrating through a thick unsaturated zone of a sandy aquifer.
Hunkeler Daniel, Aravena Ramon, Shouakar-Stash Orfan, Weisbrod Noam, Nasser Ahmed, Netzer Lior, Ronen Daniel (2011), Carbon and chlorine isotope ratios of chlorinated ethenes migrating through a thick unsaturated zone of a sandy aquifer., in Environmental Science & Technology, 45(19), 8247-8253.
Complementing approaches to demonstrate chlorinated solvent biodegradation in a complex pollution plume: mass balance, PCR and compound-specific stable isotope analysis.
Courbet Christelle, Rivière Agnès, Jeannottat Simon, Rinaldi Sandro, Hunkeler Daniel, Bendjoudi Hocine, De Marsily Ghislain (2011), Complementing approaches to demonstrate chlorinated solvent biodegradation in a complex pollution plume: mass balance, PCR and compound-specific stable isotope analysis., in Journal of Contaminant Hydrology, 126(1-2), 315-329.
Compound-Specific Chlorine Isotope Analysis: A Comparison of Gas Chromatography/Isotope Ratio Mass Spectrometry and Gas Chromatography/Quadrupole Mass Spectrometry Methods in an Interlaboratory Study
Bernstein Anat, Shouakar-Stash Orfan, Ebert Karin, Laskov Christine, Hunkeler Daniel, Jeannottat Simon, Sakaguchi-Söder Kaori, Laaks Jens, Jochmann Maik A., Cretnick Stefan, Jager Johannes, Haderlein Stefan B., Schmidt Torsten C., Aravena Ramon, Elsner Martin (2011), Compound-Specific Chlorine Isotope Analysis: A Comparison of Gas Chromatography/Isotope Ratio Mass Spectrometry and Gas Chromatography/Quadrupole Mass Spectrometry Methods in an Interlaboratory Study, in Analytical Chemistry, 83(20), 7624-7634.
Stable carbon isotope analysis to distinguish biotic and abiotic degradation of 1,1,1-trichloroethane in groundwater sediments
Broholm M.M., Hunkeler D., Tuxen N., Jeannottat S., Scheutz C., Stable carbon isotope analysis to distinguish biotic and abiotic degradation of 1,1,1-trichloroethane in groundwater sediments, in Chemosphere, 108, 265-273.

Collaboration

Group / person Country
Types of collaboration
Helmholtz Zentrum Munich Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Danish Technical University Denmark (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Associated projects

Number Title Start Funding scheme
138208 Isotope fractionation of volatile organic contaminants in porous media under unsaturated conditions: Mechanisms and applications 01.11.2011 Project funding (Div. I-III)

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