Hydrochemical Characterization and Pollution Assessment of Groundwater in Yendogo and Its Environs, Sokoto Basin, Northwestern Nigeria

Abstract

Groundwater is the principal source of water for domestic and agricultural activities in Yendogo and its environs, Sokoto Basin, northwestern Nigeria. Assessing its hydrochemical characteristics and pollution status is essential for sustainable groundwater management under changing climatic conditions. This study assessed the hydrochemical characteristics, pollution status, and suitability of groundwater for domestic use. Field investigations, groundwater sampling, and in-situ measurements of pH, temperature, electrical conductivity (EC), and total dissolved solids (TDS) were carried out. Laboratory analyses were conducted to determine major ions and selected heavy metals, while the analytical data were processed using AquaChem, Microsoft Excel, and Surfer software and compared with World Health Organization (WHO) drinking water guidelines. Groundwater was generally fresh, slightly acidic, and moderately mineralized, with temperature ranging from 28.0–31.8°C, pH 4.78–5.90, EC 159–772 µS/cm, and TDS 112–360 mg/L. Hydrochemical analysis showed that groundwater is predominantly of the Ca–Mg–HCO₃ hydrochemical facies, indicating that groundwater chemistry is mainly controlled by carbonate dissolution and natural rock–water interactions. Most physicochemical parameters and major ions and the selected heavy metals were within WHO permissible limits. However, lead (Pb) concentrations exceeded the WHO guideline value in some sampling locations, indicating localized contamination and the need for continuous groundwater quality monitoring. Overall, the groundwater is generally suitable for domestic use; however, appropriate treatment is recommended before consumptions in areas where elevated lead concentrations were observed.