Geochemical evolution and quality assessment of groundwater resources at the downstream section of the Kano-Challawa River system, Northwest Nigeria

Abstract

ABSTRACT This study was carried out to investigate the spatial variations and pollution source of the Kano-Challawa groundwater for the sustainable management of water resources. Seventy-two groundwater samples were collected from twelve sampling points (GW1-GW12) along the downstream of the Kano-Challawa River system and twenty-nine groundwater quality variables were analysed. The main findings from this study were: (1) Six varimax factors from principal component analysis were extracted and accounted for 80.660% of the total variance and revealed natural process of silicate mineral and anthropogenic influences are the major common sources of groundwater pollution. (2) Hierarchical cluster analysis grouped the sampling points into four clusters (group 1: GW8, GW11; group 2: GW1, GW5, GW10, GW12; group 3: GW7, GW3, GW4; group 4: GW2, GW6, GW12) based on similarities of the groundwater characteristics. (3) The Piper tri-linear plot revealed the five groundwater types: (Ca2+-Mg2+-Cl−) (Ca2+-Na+-) (Na+-Cl−) (Na+-) (Na+-) thereby indicating the nature of the groundwater chemistry of the Kano-Challawa River system. Furthermore, correlation coefficient analysis revealed the linear relationships among the chemical parameters, where the total dissolved solids (TDS) had significant multiple correlations with Na+, K+, Mg2+, Ca2+, and Cl− indicating the leaching of natural salts into the groundwater aquifer. The pH had a negative moderate to strong correlation with all the parameters except Ca2+, Na+, K+, and indicating an increase in the concentration of most of the constituents and the risk of salinization in the study area.