Geochemical Contribution to the Understanding of Groundwater Mineralization in Southeastern Coastal Côte d'Ivoire

Abstract

The main objective of the study carried out in the south-eastern coastal region of Côte d'Ivoire was to determine the hydrogeochemical origin of groundwater mineralization. Understanding the interactions between water and the surrounding rocks is essential for identifying the root causes of mineralization, anticipating changes in water quality, and proposing strategies for sustainable management of aquifer resources The methodology adopted was based on a hydrochemical study, a projection of chemical concentrations in the Korjinski diagram and a geochemical analysis on total rock. The results of the hydrochemical study showed that the groundwater is acidic, with pH ranging from 1.57 to 6.77. The groundwater is well oxygenated and exhibits low mineralization, consistent with regional hydrochemical characteristics. In these waters, the order of ion abundance is as follows: NO3- > Cl- > HCO3- > SO42- for anions and Ca2+ > Na+ > Mg2+ > K+ for cations, giving groundwater (wells and boreholes) a calcic hydrogen carbonate, calcic chloride and sodi-potassium chloride facies. In the Korjinski diagram, groundwater belongs to the kaolinite stability domain, which is formed by the alteration of anorthite and muscovite. From a geochemical point of view, the study reveals that the enrichment of groundwater in Na+ and Ca2+ compared to K+ and Mg2+ is mainly linked to the hydrolysis of reservoir rock minerals. Moreover, the  chemical composition of the water in these elements evolves identically to that of the aquifer rocks.