GEOSPATIAL ANALYSIS OF GROUNDWATER QUALITY VARIATION FOR DOMESTIC USE IN GOMBE METROPOLIS, NIGERIA

Abstract Groundwater remains a vital resource for domestic use in rapidly urbanizing environments such as Gombe Metropolis, Nigeria, yet its quality is increasingly threatened by human activities and poor waste management. This study investigates the spatial variability of groundwater quality for domestic use in Gombe Metropolis, Nigeria, using a geospatial approach. This study assessed groundwater suitability by comparing physicochemical and microbiological parameters with World Health Organization (WHO) and Nigerian Standard for Drinking Water Quality (NSDWQ) guidelines. A multistage random sampling technique was adopted to select 42 groundwater samples across 14 wards across Gombe, Akko, Kwami, and Yamaltu-Deba LGAs. Water samples were analyzed for temperature, pH, electrical conductivity (EC), total dissolved solids (TDS), major cations (Ca²⁺, Mg²⁺, Na⁺, K⁺), anions (Cl⁻, NO₃⁻, SO₄²⁻, PO₄³⁻, HCO₃⁻, F⁻), heavy metals (Pb, As, Cu, Fe), and microbial indicators (total coliforms, E. coli), using standard laboratory procedures including Atomic Absorption Spectrophotometry (AAS). Spatial analysis and kriging interpolation in ArcGIS were employed to generate geospatial distribution maps, while inferential statistics such as ANOVA and T-tests assessed parameter variation. Findings revealed significant spatial disparities in water quality. Notably, high nitrate (32.23 mg/L) and arsenic (0.40 mg/L) concentrations were detected in Barunde and Jeka da fari respectively, while Shamaki and Ajiya showed elevated EC (1348.63 µS/cm) and TDS (239.22 mg/L) levels. Microbiological contamination was highest in Jeka da fari and Nasarawo. Kriging maps revealed hot spots of chemical and microbial contamination primarily in urbanized wards, indicating anthropogenic influence. Conversely, Liji and GRA exhibited relatively low contaminant concentrations, suggesting minimal pollution. The study recommends routine groundwater monitoring, improved urban waste management, community education on sanitation, and targeted treatment technologies to ensure safe drinking water. This integrated geospatial framework provides an essential tool for water quality management and sustainable planning in fast-growing urban centres.