Water quality assessment and supply challenges in Thabazimbi Local Municipality of South Africa

Abstract

The global distribution of freshwater resources is irregular, and scarcity is increasing due to population expansion and anthropogenic activities. The present study assessed the community of Thabazimbi Local Municipality’s perception of daily water supply and water quality challenges they face. For this process, the study evaluated the seasonal physico-chemical, microbial, and chemical quality of drinking water sources in five villages within the Municipality, South Africa. A total of 252 water samples were collected from groundwater sources (boreholes) and treated tap water points during the wet and dry seasons and analysed for seasonal physico-chemical and microbial characteristics. A mixed-methods approach was exploited to explore perception from the participants. The quantitative approach was conducted with 250 respondents to determine their demographic characteristics, sources of water used, the reliability of these sources, the appearance of the water, and levels of user satisfaction, using a questionnaire. Additionally, for the qualitative phase, five semi-structured interviews were conducted with community water users, water officials, and water tankers to gain a deeper understanding of the area's challenges with water provision. The findings revealed that 65.60% of the respondents relied on a municipal treated water source. In comparison, 32% used boreholes as their primary water source, with over 81.60% reporting that their primary source was sometimes interrupted or unavailable. During the interruptions, 43.37% reported using alternative water sources, such as water tanker services or local water vendors in their area. Regarding water quality, only 24.10% reported consistently clear water, while 32.13% experienced occasionally cloudy water; 25% consistently were subjected to unclear water, and 18.88% frequently had discoloured water. A Regression Analysis revealed a statistically significant relationship between perceived water cleanliness and satisfaction with water services (R = 0.584, R² = 0.341, p < 0.001). Qualitative data from interviews with municipal staff and water tankers in the study area revealed critical water quality and supply challenges. The primary issues included - poor coordination between stakeholders, a lack of water treatment at the source, inadequate water monitoring, limited operational infrastructure, and inconsistent water distribution. These results were visually presented using thematic network mapping to highlight interconnections between governance limitations and infrastructure shortages. The results of the water quality analysis revealed that the key physico-chemical parameters of the groundwater exceeded the recommended guidelines for drinking water by South African National Standards (SANS 241). Total Dissolved Solids (TDS) and Electrical Conductivity (EC) in most studied boreholes, for example, GW1, GW4, GW9, exceeded the World Health Organization and South African National Standards 241:2015 guidelines, particularly during the wet season. Microbial contamination was widespread and severe. Escherichia coli was detected in 71% and 57% of groundwater samples in the wet and dry seasons, respectively, indicating faecal contamination. Treated tap water also showed non-compliance, with E. coli detected at some sites, indicating treatment failures or post-treatment contamination. The chemical analysis identified nitrate as the most significant chemical contaminant, with most sites exceeding the safe limit of 50 mg/L, primarily linked to agricultural activity. Fluoride levels in two boreholes (GW12, GW13) exceeded the 1.5 mg/L guideline, which may be associated with geogenic sources, particularly the weathering of fluoride-bearing minerals in the local geology. The mean concentrations of the major cations followed the general order of Mg²⁺ > Na⁺ > Ca²⁺ > K⁺ for both groundwater and treated water sources. Manganese and iron exceeded SANS 241 limits (max: 649 μg/L and 1030 μg/L, respectively). Chromium and arsenic were near the guideline limits (46.4 μg/L and 9.16 μg/L); all other metals measured (Al, V, Co, Ni, Cu, Zn, Se, Cd, Sb, Hg, Pb) were within safe limits. Quantitative Microbial Risk Assessment (QMRA) estimated annual infection risks for children approaching 100% at numerous sites, vastly exceeding the WHO acceptable risk of 10-4. A non-carcinogenic risk assessment for trace metals revealed hazard levels, primarily from arsenic and chromium in GW1 and GW12, with children being 3-5 times more vulnerable than adults. The Water Quality Index (WQI) classified most of the studied tap water and groundwater samples as “Excellent to Good”, however, some groundwater samples from boreholes GW1, GW3, and GW5 were classified as “Poor” due to the combined influence of multiple chemical parameters, exceeding guideline limits, resulting in low WQI values. This research revealed that the studied areas face critical water quality and supply challenges, with water sources often interrupted or unavailable. It is recommended that intervention policies be put in place and that the water source be treated prior to consumption.