1. a Water and Health, Ethiopian Institute of Water Resources (EiWR), Addis Ababa University, P.O. Box: 1176, Addis Ababa, Ethiopia
2. b Department of Environmental Sciences, Wachemo University, P.O. Box: 667, Hosanna, Ethiopia
3. c Department of Environmental Health and Technology, Jimma University, P.O. Box: 1995, Jimma, Ethiopia