Faculty of Health Sciences
School of Health Systems and Public Health
School of Health Systems and Public Health
Selected Highlights from Research Findings
The influence of environmental chemicals such as of p,p’-dichlorodiphenyltrichloroethane (DDT) on human health is a source of growing concern.
Although DDT has been banned internationally for agricultural use, countries like South Africa are allowed restricted use for malaria vector control.
South Africa is a signatory to the Stockholm Convention on the control of Persistent Organic Pollutants (POP's), and now has the obligation to limit and control the release of substances like DDT into the environment.
A cross-sectional epidemiological study was conducted to investigate the effects of DDT on male reproductive health. Participants in the study comprised more than three hundred men from Venda in the Limpopo province – an area where houses are still sprayed with DDT.
Data generated during the study included semen analyses, toxicological target analyses and hormone profiles. The results indicate that very high concentrations of DDT and metabolites are present in the men’s blood serum, and that various sperm parameters are negatively affected.
The effects of DDT on seminal parameters may not be ignored and the project will be extended. The outcomes of this research provide invaluable data on the human health effects of exposure to DDT, and will support National Government and the Department of Environmental Health and Tourism in planning and decision-making. Prof C de Jager
Health Systems and Public Health
+27 (0) 12 841 2684
tiaan.dejager@up.ac.za
The World Health Organisation reports that a quarter of all preventable diseases are due to a poor physical environment, and that those most affected by such diseases are children below five years of age.
These findings have provided the impetus for a study aimed at identifying the health risks associated with indoor air pollution due to the use of dirty fuels such as wood, dung, coal or paraffin for cooking and heating.
The data for the study were derived from the 1998 South African Demographic and Health Survey (SADHS) – the first national cross-sectional survey that involved 13 826 individuals in 12 763 households. The results of this survey were subjected to statistical analysis to determine the influence of dirty fuel use on respiratory health and child mortality while controlling for other risk factors.
The outcomes of this analysis suggest that air pollution exposure carries a large public health risk in South Africa. For instance, after controlling for other potential risk factors it was found that children living in households using dirty fuels are twice as likely to die before the age of 59 months as are children living in households that do not use dirty fuels.
Since health status and risk factors were measured simultaneously, it is difficult to unravel the temporal sequence of events. The results thus do not provide incontrovertible evidence that the use of dirty fuels is a major cause of health problems.
The study therefore recommended that comprehensive environmental public health tracking networks be established in all major cities in the country.
Dr J Wichmann
Health Systems and Public Health
+27 (0) 12 841 3240
jwichmann@med.up.ac.za
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