Assessment of stored water quality and its implications on human health in the Madombidzha area, Limpopo Province, South Africa

Abstract

Access to safe drinking water remains a critical public health challenge in many rural communities in South Africa. In Madombidzha Village, Limpopo Province, many households rely on untreated borehole water and prolonged household storage, practices that may compromise water quality and increase health risks. This study aimed to administer 278 household questionnaires to assess water-use and storage practices. Forty water samples (20 borehole and 20 stored household samples) were collected during both wet and dry seasons and analyzed in triplicate to evaluate physicochemical parameters (including pH, electrical conductivity, total dissolved solids, turbidity, major ions, and trace metals) and microbiological indicators (total coliforms and Escherichia coli). Health risks were estimated using Quantitative Microbial Risk Assessment (QMRA). The results revealed significant seasonal and spatial deterioration in water quality. Physicochemical analysis showed pH values in both borehole (6.33–9.00) and stored water (5.89–9.70), with increased alkalinity during the dry season. Electrical conductivity and total dissolved solids were exceptionally high in many samples, frequently exceeding South African National Standards (SANS 241) limits, indicating severe mineralisation. Nitrate concentrations were extremely elevated in all boreholes (65.03–976.13 mg/L) and in most stored water samples (up to 379.89 mg/L), far exceeding recommended guidelines and posing a substantial risk of methemoglobinemia. Chloride levels also surpassed aesthetic thresholds in most sites, while sulphate and fluoride remained within acceptable limits. Magnesium concentrations exceeded recommended limits in several boreholes and storage containers, whereas sodium, potassium, and calcium were generally within acceptable ranges, with some site-specific variability. Most trace metals complied with SANS 241 limits, although isolated exceedances of zinc and lead were observed, likely linked to corrosion, geological mineralisation, and container leaching. Microbiological analysis showed widespread contamination. All boreholes tested positive for total coliforms, and 78% were contaminated with E. coli. Stored water exhibited further deterioration, with higher microbial loads observed particularly during the wet season, likely due to runoff, infiltration, and poor container hygiene. QMRA indicated a high annual probability of infection (0.5–1.0) among consumers of both borehole and stored water, with children at greatest risk. Overall, the findings demonstrate that borehole and stored household water in Madombidzha Village are unsafe