ABSTRACT
ABSTRACT: Groundwater nitrate exceeds drinking water specifications in many parts of the southern African region. High nitrate levels in drinking water lead to infant methaemoglobinaemia and, at higher levels, livestock poisoning. Both are potentially fatal. A simplified map of nitrate occurrences in Botswana, Namibia and South Africa indicates regionally significant areas of high nitrate levels. Case studies in some of these areas show the extent of nitrate pollution observed during the past two decades. Isotopic methods indicated that the nitrate in groundwater can be derived from natural or anthropogenic sources. Nitrate originating from anthropogenic sources is the major problem and needs to be approached as an environmental management issue. Cattle husbandry, in the form of feedlots and concentrations around watering points, has great pollution potential and has caused fatalities. On-site sanitation systems also caused fatalities and have led to the abandoning of well fields. The impact of industry and sewage sludge disposal seems to be locality limited, while fertilizer use by agriculture was low and did not have any significant effect on groundwater. The lack of recorded information on the occurrence of infant methaemoglobinaemia and livestock losses tends to obscure the seriousness of the situation among developing nations. There is a need for a better understanding of the processes leading to nitrate pollution, natural enrichment, and impact on the health of the population.
