IRUNDE, Regina, Chemistry, UDSM, P.O.Box 35061, Dar Es Salaam, 35061, Tanzania, United Republic of; KTH-International Groundwater Arsenic Research Group, Department of Sustainable Development, Environmental Science and Engineering, KTH Royal Institute of Technology, Teknikringen 10B, Stockholm, 100 44, Sweden, LIGATE, Fanuel, Department of Water Resources Engineering, College of Engineering and Technology, University of Dar es Salaam, Dar es Salaam, Tanzania, United Republic of; KTH-International Groundwater Arsenic Research Group, Department of Sustainable Development, Environmental Science and Engineering, KTH Royal Institute of Technology, Teknikringen 10B, Stockholm, SE-100 44, Sweden; Department of Chemistry, Mkwawa College of Education, University of Dar es Salaam, Dar es Salaam, P.O.Box 35091, Tanzania, United Republic of, IJUMULANA, Julian, Department of Water Resources Engineering, College of Engineering and Technology, University of Dar es Salaam, Dar es Salaam, Tanzania, United Republic of; Department of Sustainable Development, Environmental Science and Engineering, KTH Royal Institute of Technology, Teknikringen 10B, Stockholm, 100 44, Sweden, GUSTAFFSSON, Jon-Petter, KTH-International Groundwater Arsenic Research Group, Department of Sustainable Development, Environmental Science and Engineering, KTH Royal Institute of Technology, Teknikringen 10B, Stockholm, 100 44, Sweden, MAITY, Jyoti Prakash, Earth and Environmental Sciences, National Chung Cheng University, 168 University Road, Ming-Shung, Chia-Yi County, 62102, Taiwan, BHATTACHARYA, Prosun, Department of Sustainable Development, Environmental Science and Engineering, KTH Royal Institute of Technology, Teknikringen 10B, Stockholm, SE-100 44, SWEDEN, MTALO, Felix W., Department of Water Resources Engineering, College of Engineering and Technology, University of Dar es Salaam, Dar es Salaam, Tanzania, United Republic of and AHMAD, Arslan, Department of Environmental Technology, Wageningen University and Research (WUR), Wageningen, 6708 PB, Netherlands; SIBELCO Ankerpoort NV, Op de Bos 300, Maastricht, 6223 EP, Netherlands