1. Department of Chemistry, College of Natural and Applied Science, University of Dar es Salaam, P.O. Box 35061, Dar es Salaam, Tanzania
2. Department of Water Resources, Water Institute, P.O. Box 35059, Dar es Salaam, Tanzania
3. Tanzania Agricultural Research Institute, Mikocheni, P.O. Box 6226, Dar es Salaam, Tanzania
4. Department of Geography & Environmental Studies, Sokoine University of Agriculture, Morogoro, Tanzania