1. Wollega University, College of Natural and Computational Sciences, Department of Environmental Sciences, P.O. Box: 395, Nekemte, Ethiopia
2. Ambo University, College of Agriculture and Veterinary Sciences, Department of Natural Resource Management, P.O. Box: 19, Ambo, Ethiopia
3. Wollega University, College of Natural and Computational Sciences, Department of Chemistry, P.O. Box: 395, Nekemte, Ethiopia