Pollution status and health risk assessment of groundwater aquifers in Ekpan community, Delta State, Nigeria

This study evaluates the human and ecological risks associated with physicochemical pollutants in groundwater aquifers of Ekpan community, Delta State, Nigeria. Twelve borehole water samples drawn from both shallow and deep aquifers were analyzed using standard protocols to determine their physicochemical properties and heavy metal concentrations. Results showed that pH (6.23), temperature (24.51 °C), and electrical conductivity (160 µS/cm) were within permissible limits set by the World Health Organization (WHO) and Nigeria’s Federal Ministry of Environment. Most parameters, including total dissolved solids, biochemical oxygen demand, total hardness, and major ions (Na+, Ca2+, Mg2+, SO42−, NO3−), were below recommended limits, except potassium (5.3 mg/L), which exceeded WHO standards. Heavy metal concentrations followed the order: Al > Cd > Zn > Cr > Pb > Cu > Fe > Ni > Mn > As > Hg. Notably, potassium exceeded limits in both seasons, while cadmium and lead were elevated during the rainy season. Ecological indices revealed that 60% of borehole samples were unsuitable for drinking. Cancer risk estimates ranged from 1.5 × 10−5 to 2.3 × 10−4 for adults and 2.0 × 10−5 to 3.1 × 10−4 for children. Non-cancer risks showed hazard quotients above acceptable thresholds for several metals, with children being more vulnerable, especially during the rainy season. These findings underscore the urgent need for continuous groundwater monitoring and effective management strategies to safeguard public health.