The occurrence of fluoride in South African groundwater: A water quality and health problem

Abstract

Groundwater is the most appropriate and widely used source of drinking water for many rural communities in South Africa. Pilot studies and surveys conducted by the Department of Water Affairs and Forestry (DWAF) indicated that there are a number of boreholes across the country that contain apart from fluoride, levels of nitrate, some heavy metals, total dissolved solids, sulphates and faecal coliforms (in some regions) that could pose a health risk if the water is used for drinking purposes. Very few boreholes have been tested for heavy metals or toxic organic substances. However, considering the levels of fluoride, in general, groundwater is of acceptable quality except for some areas in which elevated levels of natural groundwater fluoride occur. The study on which this paper is based was conducted to identify areas of high groundwater fluoride concentration in South Africa and to relate this to the occurrence of dental fluorosis in most communities using the groundwater for domestic use. Two sets of data were used. The fluoride data were obtained by extracting fluoride groundwater quality data from DWAF’s Water Management Systems (WMS) database. STATISTICA and ARCVIEW were used to process the data. The dental fluorosis data were obtained from a field study conducted by the Department of Health. The degree of dental fluorosis was determined using Dean’s classification criteria for dental fluorosis. The occurrence of dental fluorosis was observed in those areas in which fluoride levels were higher than the recommended guidelines for drinking water. The degree and severity of mottling in the subjects studied by the DOH team, corresponded with the level of fluoride in drinking water and the percentage morbidity of dental fluorosis varied from province to province, district to district and village to village.