1. Climate and Environmental Physics, Physics Institute University of Bern Switzerland
2. Also at Water Resources and Drinking Water, EAWAG, Dübendorf, Switzerland.
3. Water Resources and Drinking Water EAWAG Dübendorf Switzerland
4. Now at Institute of Environmental Physics, University of Heidelberg, Heidelberg, Germany.
5. Also at Isotope Geology, ETH Zurich, Switzerland.
6. Département de Géologie Université Abdou Moumouni Niamey Niger