1. Helmholtz Zentrum München, Institute of Groundwater Ecology, 85764 Neuherberg, Germany
2. Centre for Hydrogeology and Geothermics (CHYN), University of Neuchâtel, 2000 Neuchâtel, Switzerland
3. Swiss Federal Institute of Aquatic Science and Technology (Eawag), 8600 Dübendorf, Switzerland
4. Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, 81377 Munich, Germany