Fiddausi Dayyabu, Mustapha Zakariyya Karkarna, Nura Umar Kura, Surayya Farouk Durumin iya
Groundwater is the primary source of domestic water in Kano Metropolis, yet its quality is increasingly threatened by rapid urbanization and anthropogenic activities. This study evaluated the spatiotemporal variation in groundwater quality using systematic sampling and multivariate statistical approaches. Forty-eight water samples (24 boreholes and 24 wells) were purposely collected across eight Local Government Areas during dry and wet seasons (feb-sept 2023). Physicochemical parameters were analyzed in line with WHO standards. Results indicated significant seasonal differences, with higher contamination observed during the dry season. Chloride concentrations peaked at 579.38 mg L⁻¹, turbidity at 8.01 NTU, and total dissolved solids (TDS) at 538 mg L⁻¹, both exceeding WHO permissible limits and posing potential risks of salinity-related health effects. Principal Component Analysis (PCA) identified four key factors explaining 76.1% of the total variance, attributed to salinity and mineralization, carbonate buffering, organic contamination, and sulphate enrichment. Agglomerative Hierarchical Clustering (AHC) distinguished boreholes, which showed relative stability, from wells, which were highly susceptible to surface contamination. Hydrochemical facies plots from Piper diagrams revealed dominance of Ca–Mg–SO₄–Cl and Ca–Mg–Cl–SO₄ water types, reflecting both geogenic and anthropogenic influences. The findings demonstrate that groundwater in Kano is vulnerable to deterioration from industrial effluents, poor sanitation, and unregulated land-use practices. To mitigate contamination risks, the study recommends an integrated groundwater management strategy that includes continuous monitoring, stricter waste disposal regulations, improved well and borehole siting, and community education on water safety. These interventions are critical to ensuring long-term groundwater sustainability and safeguarding public health in the metropolis