1Water and Environmental, Applied Geoscience, Council for Geoscience, 280 Pretoria Street, Silverton, Pretoria Street, Silverton, Pretoria, 0001, South Africa
2Department of Environmental Sciences, Florida Campus, University of South Africa, P O Box X6, Florida, 1710, South Africa
3Department of Water Affairs, Resources Quality Services (RQS), Roodeplaat, 0001 Pretoria, India
4Chemistry Department, Vaal University of Technology, Private Bag X021, Vanderbijl park, 1911, South Africa