1. Department of Environmental Management, Pan African University Life and Earth Sciences Institute, University of Ibadan, Ibadan, Nigeria
2. Mabibo Medical Research Centre, National Institute for Medical Research, P. O. Box 9653, Dar es Salaam, Tanzania
3. Department of Petroleum and Energy Engineering, College of Earth Science, The University of Dodoma, P. O. Box 259, Dodoma, Tanzania
4. Department of Geology, Pan African University Life and Earth Sciences Institute, University of Ibadan, Ibadan, Nigeria
5. Department of Physics, College of Natural and Mathematical Sciences, University of Dodoma, P. O. Box 259, Dodoma, Tanzania