Groundwater Quality Assessment, Trace Element Pollution, and Health Risk Assessment of Hand-Dug Wells within Ladoke Akintola University of Technology Campus and Environs, Ogbomoso, Southwestern Nigeria

Abstract

Groundwater is the primary source of potable water within Ladoke Akintola University of Technology (LAUTECH). Natural geochemical processes and increasing anthropogenic activities may compromise its quality and pose potential health risks. This study evaluated the physicochemical characteristics, trace-element concentrations, groundwater pollution status, and associated health risks of groundwater from thirty-nine (39) hand-dug wells. Sixteen (16) wells were selected for detailed pollution-index and health-risk assessments based on their spatial distribution and contamination characteristics. Physicochemical parameters and trace-element concentrations were determined using standard analytical procedures. Groundwater pollution was evaluated using the Heavy Metal Pollution Index (HPI), Heavy Metal Evaluation Index (HEI), and Contamination Index (Cd). Health risks were assessed using United States Environmental Protection Agency (USEPA, 2011) models based on the Hazard Quotient (HQ), Hazard Index (HI), and Cancer Risk (CR). The groundwater was moderately acidic to neutral (pH 4.92–6.94), and most physicochemical parameters complied with the World Health Organization (WHO, 2022) and Nigerian Standard for Drinking Water Quality issued by the Standards Organisation of Nigeria (SON, 2015) guideline values. Elevated concentrations of cadmium (Cd), lead (Pb), and nickel (Ni) were detected in representative wells, resulting in varying degrees of groundwater contamination. The HI ranged from 0.216 to 0.639 for adults and from 0.504 to 1.491 for children. All adult HI values were below the acceptable threshold, whereas selected wells recorded values greater than one for children, indicating potential non-carcinogenic health risks. Total Cancer Risk (TCR) values ranged from 1.23 × 10⁻³ to 3.72 × 10⁻³ for adults and from 2.87 × 10⁻³ to 8.68 × 10⁻³ for children, exceeding the USEPA acceptable cancer-risk range (10⁻⁶–10⁻⁴) in all assessed wells. Cadmium and nickel were the principal contributors to carcinogenic risk. The results emphasise the need for continuous groundwater-quality monitoring, effective waste management, source protection, and appropriate groundwater treatment to safeguard public health.