1. Centre for Environmental Management, University of the Free State, Bloemfontein, South Africa
2. Graduate Mastery, Boskruin View Office Park, Randburg, South Africa
3. Department of Life Sciences, Central University of Technology, Bloemfontein, Free State, South Africa
4. School of Chemistry and Physics, University of KwaZulu-Natal, Durban, KwaZulu-Natal, South Africa
5. Department of Chemistry, University of Manchester, London, UK