Multivariate Hydrochemical Characterization and Spatial Variability of Groundwater Quality in Kano Region, Nigeria: Insights into Natural Geology and Anthropogenic Influence

This research detailed a hydrochemical investigation and spatial variability examination of the groundwater quality of five principal sites in Kano Region, Nigeria, namely Hotoro, Kano Municipal, Kumbotso, Kofar Fada, and Gezawa, with a total of Fifty-one (51) water samples collected. Physical, chemical and biological parameters assessed in the water samples were Electrical Conductivity, Hardness, pH, Total Dissolved Solids (TDS), Temperature, Turbidity, Dissolved Oxygen (DO2), major cations (Na+, K+, Mg2+, Ca2+) and trace metals (Cr, As, Fe, Zn, Cu, Ni, Pb, Cd). The data demonstrate a high level of spatial heterogeneity that can be considered when examining not only natural geological structures but also anthropogenic factors, particularly urbanized and peri-urban districts of Kano and certain parts of the surroundings, where increased Conductivity, TDS, Hardness, and several ion concentrations were observed. The pH was usually in a slightly acidic to slightly alkaline range, with poor levels of Dissolved Oxygen indicating a possible impact of organic contaminants or the eutrophication phenomenon. Two multivariate visualizations (Boxplots, Scatter plots) and multiple correlation matrices, PCA, and Piper diagrams help clarify the complicated correlation of the constituents of water quality. The Piper diagram revealed unique hydrochemical facies, primarily Sodium-Chloride and Calcium-Magnesium Bicarbonate, which combined the natural geochemistry of sediments with urban anthropogenic effects. The concentrations of Trace metals were generally low with little acute risk proclaimed, but localized areas of potential concern were indicated by periodic increases of Iron and Zinc. The inter-area differences were strongly indicated by statistical testing, which pointed to the need for specific water resource management approaches and pollution control strategies. In general, the combination of spatially addressed hydrochemical observations with the information on spatial data and its analysis presents the opportunity for a crucial contribution to sustainable monitoring of water quality and environmental management in the Kano area, and contributes to rational decisions to preserve the health of the general population and aquatic ecosystems.