Integrated hydrochemical and microbiological assessment of groundwater quality for early contamination detection and preventive management

Abstract Groundwater is a critical source of drinking water in many rural areas and peri-urban communities; however, both geochemical and microbiological factors increasingly influence its suitability. This study presents an integrated assessment of groundwater quality in mining and agriculture-influenced communities of Ghana (Segyemase, Juaso and Nsuapemso) using hydrochemical characterization, water quality indices, microbiological indicators and risk-based interpretation. Sixteen borehole water samples were analysed for physicochemical parameters, major ions and selected trace metals, alongside microbial indicators including total coliforms, faecal coliforms, Escherichia coli , Salmonella spp . and Vibrio spp. Hydrogeochemical processes were evaluated using ionic ratios, saturation indices and Piper diagrams, while groundwater suitability for drinking was assessed using the Water Quality Index (WQI) and complementary pollution indices. Microbiological quality was evaluated through descriptive statistics, exceedance analysis and risk-based assessment. Results indicate that groundwater chemistry is predominantly controlled by the water-rock interaction process, with Ca-HCO 3 and Ca-Mg-SO 4 facies reflecting spatial variability linked to lithology and mining influence. All sampled boreholes were classified as excellent for drinking based on WQI values. Pollution indices (GPI, WPI and CPI) generally indicated low to moderate physicochemical impairment, whereas the Water Nutrient Pollution Index (WNPI) identified localised nutrient impacts and the Ecological Risk Index (ERI) classified all samples as low ecological risk. However, microbiological assessment revealed the widespread occurrence of total coliforms and the localized detection of faecal coliforms and E. coli in two boreholes, indicating sanitary vulnerability and a potential public health risk. These findings demonstrate that chemical suitability does not necessarily equate to microbiological safety. Integrated interpretation enabled prioritization of high-risk boreholes for targeted intervention and informed community-level risk communication. The study highlights the importance of combining hydrochemical assessment, water quality indices, pollution indices, microbiological monitoring and risk-based frameworks to support early contamination detection, evidence-based groundwater management and preventive public health protection.