Groundwater quality assessment and public health implications in Güyük and its surrounding communities, northeastern Nigeria

Groundwater is the primary source of potable water for the inhabitants of Guyok and its surrounding communities in Northeastern Nigeria. Its quality is controlled by the geological formations through which it percolates and by anthropogenic activities. This study assesses the hydrochemistry of groundwater from boreholes and hand dug wells, with emphasis on major ions, physicochemical parameters, and bacteriological indicators. The analysed parameters were compared with World Health Organization (WHO,2017) standards to determine suitability for drinking and domestic use. Results show alkaline pH values ranging from 7.96 to 9.30, while electrical conductivity (234–321 µS/cm), total dissolved solids (157.1–273.0 mg/L), and total hardness (122.9–210.0 mg/L) fall within permissible limits. Major ion concentrations (Ca²⁺, Mg²⁺, Na⁺, K⁺, Fe²⁺, Mn²⁺, Cl⁻, NO₃⁻, and SO₄²⁻) also comply with WHO guideline values. In contrast, bacteriological analysis revealed elevated coliform counts in hand dug wells, reaching up to 27 cfu/mL, indicating susceptibility to microbial contamination. Overall, groundwater in the area is chemically suitable for domestic use; however, bacteriological contamination poses significant public health risks, including waterborne diseases such as diarrhoea, typhoid, and cholera. Variations between borehole and hand dug well water quality reflect differences in aquifer depth, geological protection, and land use practices. The findings provide baseline data for groundwater quality management in semi urban communities of Northeastern Nigeria and underscore the need for improved groundwater protection, routine monitoring, and community-based water treatment interventions.