Microbial water quality in the upper Olifants River catchment: implications for health

Abstract

The Olifants river has been described as one of the most environmentally polluted rivers in Southern Africa, particularly in the upper catchment. Untreated water from the catchment may be used for many purposes including irrigation, recreation, consumption, and domestic purposes. As poor water remains a leading cause of morbidity and mortality, it is essential to understand the health risks that the water users in the Olifants catchment are exposed to. The aim of this research was to identify the extent of the microbiological pollution in the upper Olifants River catchment and determine the sources of the microbial contaminants by monitoring faecal indicator levels and selected water-borne pathogens. It was shown that sections of the upper Olifants River catchment are highly contaminated with faecal indicator bacteria and pathogenic microorganisms. A quantitative microbial risk assessment was also performed and it showed that the polluted waters pose an unacceptably high risk to water users within this catchment. In all regions where extreme levels of faecal pollution were observed, the source could be traced back to inadequate wastewater treatment. The microbial water quality in the upper Olifants River catchment could therefore be remediated to a large extent by ensuring proper functioning of wastewater treatment works.