1. Department of Earth and Environmental Sciences, Botswana International University of Science and Technology (BIUST), Palapye, Botswana
2. Department of Mining and Geological Engineering, Botswana International University of Science and Technology (BIUST), Palapye, Botswana
3. Department of Aquatic Geochemistry/Geochemistry and Mineral Resources, Karlsruhe Institute of Technology, Karlsruhe, Germany