1. School of Agriculture, Earth and Environmental Science, College of Agriculture Engineering and Science, University of KwaZulu Natal, Durban, South Africa
2. School of Chemistry and Physics, College of Agriculture Engineering and Science, University of KwaZulu Natal, Durban, South Africa
3. Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
4. Environment and Health Research Unit, South African Medical Research Council, Pretoria, South Africa
5. Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Hatfield, South Africa