Evaluation of shallow groundwater in Rural Kebbi State, NW Nigeria, using multivariate analysis: implication for groundwater quality management

Abstract

This study assessed shallow groundwater in rural Kebbi State using Pearson’s Correlation (r), Factor Analysis (FA), and Hierarchical Cluster Analysis (HCA). One hundred (100) shallow groundwater samples were drawn randomly from hand-dug shallow wells in 10 Local Government Areas (LGAs). Physical parameters (pH, temperature, TDS, EC, salinity) were analysed in situ using hand-held metres. Separate water samples were taken to analyse ions (Fe, Zn, K, Mg, Mg, HCO3, Ca). Results revealed that shallow groundwater is lightly acidic, except in Zuru and Fakai LGAs, where an alkaline condition occurred. Correlation analysis revealed that the dissolved solids in shallow aquifers result from natural geological and anthropogenic influences. However, FA had shown that most of the variability in shallow groundwater is influenced by natural geological factors with little evidence from anthropogenic inputs. The HCA categorised shallow groundwater into three groups: those shallow wells having higher concentrations of Zn and Cl with more elevated salinity and temperature; those shallow wells having very low salinity in central Kebbi State, and those shallow aquifers having alkaline waters. Except for higher Fe and Zn concentrations, the shallow aquifers contained water of excellent quality for drinking. Correlation analysis, FA, and HCA present simple statistical tools for assessing the hydrochemistry of groundwater.