1. Toxicology and Biochemistry, National Institute for Occupational Health, National Health Laboratory Service, Johannesburg, South Africa
2. Department of Environmental Health, University of Johannesburg, Johannesburg, South Africa
3. Environmental Health Division, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa
4. Water Research Group, Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
5. School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
6. Haematology and Molecular Medicine Department, University of the Witwatersrand, Johannesburg, South Africa