CHLOROKARST – Evaluation and investigation of sites contaminated with chlorinated hydrocarbons and located in karst

The number of former industrial sites or landfills polluted with chlorinated solvents located in a karstic environment is estimated to 4’427 in Switzerland, which corresponds to 16.7% of the total number of sites polluted with chlorinated solvents. These sites pose significant problems.

Swiss regulation on polluted sites (OSites 26.08.98) is indeed adapted to the polluted sites located in porous media, but not in karstic ones ! The standard investigation techniques do not help either to assess the impact of these sites on the water quality in the karstic networks, while they form important drinking water resources.

The purpose of the Chlorokarst project is to design an evaluation process for polluted sites located in karstic media, and to propose investigation techniques adapted to their specificities. The project is supported by the OFEV and is performed in partnership with the University of Neuchâtel and the MFR consulting office.

Various devices and methods are tested in the field in the Jura region : integrative passive samplers, automatic samplers, integral pumping tests, double GC analyzes, geological and hydrogeological reservoir models.

An evaluation process is currently discussed with the OFEV and is debatted with the Cantonal authorities.

The progress of the project and the first results were exposed on November 26, 2015, during the 8th Chloronet technical day. An article referring to Chlorokarst was published in the “Environnement” magazine of the OFEV, in late 2015.