1. Norwegian Geotechnical Institute (NGI), P.O. Box 3930 Ullevål Stadion, 0806 Oslo, Norway
2. Department of Plant and Environmental Sciences (IPM), Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway
3. Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, 0315 Oslo, Norway
4. Department of Geological Sciences, University of Oslo, Oslo, Norway
5. Department of Applied Environmental Sciences (ITM), Stockholm University, 10691 Stockholm, Sweden