Reevaluating the hydrochemistry of groundwater in basement complex aquifers of Kaduna Basin, NW Nigeria using multivariate statistical analysis

Evaluation of groundwater using multivariate analysis is a valuable technique. It helps to detect the source of elements and the process(es) that controls the groundwater chemistry. This review intends to identify the hydrogeochemical process(es) that controls groundwater in Kaduna Basin. Water quality data were derived from the literature based on defined literature selection criteria. Subsequently, we applied multivariate analysis, notably, factor, cluster, and correlation analyses to classify and analyse the hydrochemical conditions. Results showed that groundwater is controlled by the rock weathering process based on correlation and factor analyses. Hierarchical cluster analysis categorised groundwater into three clusters. Cluster 1 contained locations that have an analogous concentration of pH and temperature. Cluster 1 relates to physical/external influence. Cluster 2 correlated with EC, Fe 3+ , HCO 3 − , and NO 3 − . Cluster 3 correlated with TDS, Na + , Mg 2+ , Ca 2+ , K + , SO 4 2− , and Cl − . The two clusters are related to the rock weathering process, owing to low NO 3 − concentrations. Results of factor and correlation analyses concurred with Gibb's model. The study inferred that rock weathering is the primary mechanism controlling groundwater in Kaduna Basin. The multivariate analysis provides a simple tool for identifying the relationship between geology and hydrochemistry of aquifers.