Demonstrating a natural origin of chloroform in groundwater using stable isotope analysis
| Responsable du projet | Daniel Hunkeler |
| Collaborateur |
Cédric Weber
Marie Eve Wyniger Farine Florian Breider |
| Résumé |
Chlorinated hydrocarbons are among the most common groundwater
contaminants. For example, in Switzerland, in nearly a quarter of
the drinking water wells traces of chlorinated hydrocarbons are
detected. It is generally believed that these compounds originate
from anthropogenic activities such as metal processing industries
or dry cleaners. However, recently, it was found that some
chlorinated hydrocarbons, especially chloroform, can also be
naturally produced during degradation of organic matter by fungi in
forest soils. While, the natural production of these compounds has
clearly been documented at some locations, it is not known yet how
widespread this process is. For planning effective remediation
measures and risk assessment, it is important to know the source of
theses compounds. The main aim of the project is to develop a method
to identify locations where chlorinated hydrocarbons are of natural
origin, to apply the method to evaluate how widespread natural
chlorinated hydrocarbon production is and to identify conditions
under which these compounds can reach groundwater. The method to
identify the origin of chlorinated hydrocarbons relies on stable
isotope analysis. Preliminary studies have demonstrated the
chloroform from natural sources contains more of the heavy carbon
isotope, 13C, compared to the anthropogenic chloroform. The
difference can be explained by the different origin of the carbon
in the molecule. An analytical method will be developed to measure
the carbon isotopic composition of chloroform at low
concentrations. The method will then be applied to identify
locations where chloroform is of natural origin. Finally, at some
of these locations, detailed studies will be carried out to
investigate how natural chlorinated hydrocarbons can reach
groundwater. |
| Mots-clés |
groundwater, organic contaminants, isotopes, Chlorinated hydrocarbons, stable isotopes, chloroform |
| Type de projet | Recherche fondamentale |
| Domaine de recherche | Géochimie |
| Source de financement | FNS - Encouragement de projets (Div. I-III) |
| Etat | Terminé |
| Début de projet | 1-10-2008 |
| Fin du projet | 30-9-2010 |
| Budget alloué | 214'246.00 |
| Autre information |
http://p3.snf.ch/project-117860# |
| Contact | Daniel Hunkeler |