1. Eawag—Swiss Federal Institute of Aquatic Science and Technology, Department of Surface Waters Research and Management, Seestrasse 79, CH-6047 Kastanienbaum, Switzerland
2. Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitätsstrasse 16, CH-8092 Zürich, Switzerland
3. Department of Inorganic and Analytical Chemistry, University of Geneva, Quai E.-Ansermet 30, 1211 Geneva, Switzerland
4. Integrated Systems Laboratory (LSI), Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland