Hydrogeochemical and Statistical Characterization of Groundwater in the Lakes Region (Central Côte d’Ivoire)

Abstract

Rural inhabitants depend on groundwater for their drinking water in the Lakes region of central Cote d’Ivoire. The aim of this study is to identify the factors responsible of the water mineralisation and the sources of major ions in groundwater within the area. 123 groundwater samples were collected and analysed for various physico-chemical parameters. Multivariate statistical techniques including Principal Component Analysis (PCA) and Cluster Analysis (CA) were applied on the dataset to evaluate the geochemical processes that control the hydrogeochemistry of groundwater. Ca-HCO3 and Mg-Ca-HCO3 hydrochemical facies predominate the groundwater samples. The first 4 factors explain 79.139% of the total variance, their loading allowing the interpretation of hydrogeochemical processes in the area. The sources of ions in the groundwater are due to two main factors: natural mineralisation and anthropogenic activities. The silicates mineral weathering such as acid hydrolysis of silicates provide the major part of the ions in groundwater such as Ca2+, Mg2+, and HCO3-. The concentrations of NO-3 and Cl- in groundwater were due to anthropogenic activities such as farming. Reduction-oxidation process produced Mn and Fe. The results of this study show the usefulness of multivariate statistical techniques in hydrochemical studies.