1. Department of Environmental Sciences (IMV), Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway
2. Department of Soil Science, University of Zambia (UNZA), Lusaka, Zambia
3. Norwegian Geotechnical Institute (NGI), P.O. Box 3930 Ullevål Stadion, 0806 Oslo, Norway
4. Department of Applied Environmental Sciences (ITM), Stockholm University, 10691 Sweden