1. Faculty of Natural and Agricultural Sciences, Institute of Ground Water Studies, University of the Free State , Bloemfontein 9301, South Africa ; , Jamshoro 76062, Pakistan
2. Department of Basic Sciences and Related Studies, Mehran University of Engineering and Technology , Bloemfontein 9301, South Africa ; , Jamshoro 76062, Pakistan
3. Faculty of Natural and Agricultural Sciences, Institute of Ground Water Studies, University of the Free State , Bloemfontein 9301, South Africa