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

Abstract

This research detailed a hydrochemical investigation and spatial variability examination of the groundwater quality at five principal sites in the 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 (DO), major cations (Na+, K+, Mg2+, Ca2+), and trace metals (Cr, As, Fe, Zn, Cu, Ni, Pb, Cd). The data demonstrated a high level of spatial heterogeneity that should be considered when examining not only natural geological structures but also anthropogenic factors, particularly in urbanised and peri-urban districts of Kano and certain parts of the surroundings, where elevated Conductivity, TDS, Hardness, and several ion concentrations were observed. The pH was usually in the slightly acidic to slightly alkaline range, with low levels of Dissolved Oxygen indicating possible impacts from organic contaminants or eutrophication. Two multivariate visualisations (box plots, Scatter plots, multiple correlation matrices, PCA, and Piper diagrams) help clarify the complex correlations among 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 identified, but periodic increases in iron and Zinc indicated localised areas of potential concern. The inter-area differences were strongly supported by statistical testing, indicating the need for specific water resource management approaches and pollution control strategies. The statistical testing strongly indicated an inter-area difference, necessitating specific approaches to water resources management and pollution control strategies. Overall, the synthesis of spatially resolved hydrochemical measurements with spatial data and its processing has the potential to make an essential contribution to the sustainable monitoring of water quality and environmental management in the Kano region, and to support sound decisions to preserve the health of the overall population and water bodies. In general, the combination of spatially addressed hydrochemical observations with spatial data and its analysis presents an opportunity for a crucial contribution to sustainable monitoring of water quality and environmental management in the Kano area, and to rational decisions to preserve the health of the general population and aquatic ecosystems.