ASSESSMENT OF GROUNDWATER QUALITY AND HUMAN HEALTH RISK IN UVWIE AND WARRI SOUTH L.G.As., DELTA STATE, NIGERIA

Groundwater is the principal source of domestic water supply in many communities within Warri, Delta State, Nigeria; however, increasing urbanization, industrialization, and petroleum-related activities have raised concerns over its quality and sustainability. This study evaluated the hydrogeochemical characteristics and human health implications of groundwater in Uvwie and Warri South Local Government Areas, focusing on physicochemical properties, hydrogeochemical evolution, and associated health risks. Ten (10) groundwater samples were systematically collected from boreholes and hand-dug wells across the East, West, North, South, and Central zones. In-situ measurements were obtained using portable meters, while major ions and heavy metals were analyzed using standard titrimetric methods and Atomic Absorption Spectrophotometry (AAS). Data were interpreted using descriptive statistics, Piper and Gibbs diagrams, ionic ratio analysis, and Human Health Risk Assessment (HHRA) models. Groundwater was slightly acidic (pH 5.7– 6.6; mean = 6.15) with moderate mineralization (EC: 790–1080 µS/cm; mean = 913.5 µS/cm). Sodium and chloride dominated the hydrochemistry, producing mainly Na–Cl facies with mixed Na–Cl and Ca–HCO₃ water types. Piper and Gibbs diagrams indicated groundwater evolution is primarily controlled by rock–water interaction and evaporation, with some anthropogenic influence. Lead (0.010–0.021 mg/L) and cadmium (0.003– 0.006 mg/L) exceeded drinking water limits in several locations. Health risk assessment showed HQ values >1 (Pb = 1.23; Cd = 1.10), HI = 2.33, and TCR = 4.3 × 10-4, indicating unacceptable non-carcinogenic and carcinogenic risks. The study concludes that groundwater quality in the study area is influenced by both natural hydrogeochemical processes and anthropogenic contamination.