1. Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences (SLU), Box 7050, SE-75007 Uppsala, Sweden
2. Institute of Soil Science and Land Evaluation, Soil Chemistry and Pedology, University of Hohenheim, Emil-Wolff-Straße 27, 70599 Stuttgart, Germany
3. The Swedish Chemicals Agency (KemI), SE-172 67 Stockholm, Sweden