Césard Millogo^{1, 2,}, Blehiman Sagnon³, Sayoba Kafando², Samuel Nakolendoussé²

The population of the city of Manga and the surrounding area is supplied with drinking water by boreholes exploiting the fractured rock aquifer. However, these boreholes are often managed without considering the impact of natural geogenic and anthropogenic sources of toxic chemicals, which can threaten groundwater quality. Major ion geochemistry, water quality index calculations have been used to understand the hydrogeochemical processes controlling water quality. To carry out this study, 94 water samples from wells were collected and analyzed. Physicochemical parameters indicate neutral and soft waters due to low mineralization. The dominant ions are Ca²⁺, Mg²⁺, and HCO₃⁻. Most of the analyzed samples are considered excellent according to the WQI. Analysis using bivariate diagrams revealed that the main factors affecting solute acquisition in groundwater are silicate weathering, mineral dissolution and precipitation, ion exchange, and evapotranspiration. This study enabled us to assess the hydrochemical quality of the water and gain a better understanding of the physico-chemical processes controlling the mineralization of groundwater in the study area. It will therefore be a decision-making tool for sustainable water management.

groundwater, hydrochemical evolution, saturation indices, WQI, Manga, Burkina Faso