Abstract

The aim of this study is to assess the quality of the groundwater currently supplied to the rural communities of the North West Province. Groundwater samples collected from 100 boreholes in these rural areas were subjected to culture-based methods using selective media for the isolation of faecal and total coliform bacteria. Molecular analysis targeting 16S rRNA gene, and the restriction fragment-length polymorphism (RFLP) and sequence analysis of amplified gene for differentiating between species and strains of bacteria, were applied to selected coliform isolates. The physico-chemical parameters such as pH, temperature, total dissolved solids (TDS), turbidity and concentrations of chloride, sulphates, nitrate, fluoride, magnesium, sodium and calcium were also determined. The results revealed that 83% of the boreholes did not comply with the fluoride limit of SANS 241 (0 to 1 mg/l), 40% did not comply with the nitrate limit (0 to 6 mg/l as N), 45% did not comply with the magnesium limit (0 to 30 mg/l as Mg), 43% did not comply with the calcium limit (0 to 32 mg/l as Ca), 31% did not comply with TDS and 47% did not comply with the turbidity limit (<1 NTU). The results also indicated that 23 and 86% of the boreholes did not comply with the limits set by the national guidelines (SANS 241 and DWAF) in terms of faecal (0 cfu/100 ml) and total coliforms (0 to 5 cfu/100 ml), respectively. The results of the molecular study revealed that out of 100 boreholes, 51% tested positive forCitrobacter freundii, 28% for Serratia marcescens, 12% for Morganella morganii, 8% for Salmonella enterica, 7% for Aeromonas veronii, 5% for Bacillus cereus, 2% for Enterobacter cloacae and 1% for Escherichia coli and Shigella dysenteriae. The findings of this study showed convincing evidence that some groundwater supplies in rural areas of North West pose a serious health risk to consumers.

Key words: Groundwater, physical, chemical, microbiological water quality.