1. Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, Universitätstrasse 16, CHN, CH-8092 Zurich, Switzerland
2. Soil Chemistry and Biogeochemistry Group, Department of Soil Science, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand
3. Environmental Chemistry Group, Institute of Chemistry, University of Neuchâtel, Avenue de Bellevaux 51, 2000, Neuchatel, Switzerland