Water Quality Index and the quality of freshwater resource uMhlathuze river, Kwazulu-Natal, South Africa: A Review

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Abstract uMhlathuze River in KwaZulu-Natal, South Africa, is a critical freshwater resource supporting industrial, agricultural, and domestic activities. However, its water quality is under threat from various anthropogenic pressures. This review synthesises existing literature to assess the river’s water quality, focusing on key contaminants, spatial and temporal trends, ecological impacts, and socio-economic implications. Key pollutants identified include elevated levels of nitrates (>10 mg/L), phosphates (>2 mg/L), heavy metals such as lead (Pb > 0.01 mg/L) and chromium (Cr > 0.05 mg/L) (Nsibande et al. Afr. J. Aquat. Sci. 2024, 262–274, 3.), and microbial contaminants with faecal coliforms exceeding 1,000 CFU/100 mL (Mthembu et al., Afr. J. Microbiol. Res. 2012, 2020–2026, 9.). Seasonal variations exacerbate these issues, with higher pollutant loads observed during rainy periods due to increased runoff from industrial, agricultural, and urban areas. Figures illustrating contaminant trends by season or location could complement these findings. The degraded water quality has led to declines in biodiversity, including fish and aquatic macroinvertebrates, and poses significant public health risks for communities reliant on the river for drinking water and sanitation. Maps of pollution hotspots and biodiversity loss would aid in visualizing these impacts. Key knowledge gaps include inconsistent sampling methodologies, insufficient long-term data, and the absence of a region-specific Water Quality Index (WQI). This review highlights the need for standardised WQI frameworks, advanced monitoring technologies, and pollution tracking mechanisms to address these challenges. Additionally, socio-economic studies and community-based conservation initiatives are recommended to mitigate pollution impacts and improve water resource sustainability. These findings serve as a foundation for targeted research and policy actions to protect and sustainably manage the uMhlathuze River system.