Regional geochemistry of mineral waters in Algerian territory -Application of thermodynamic models-

Abstract

This study aims to analyze the hydrochemical characteristics and thermodynamic behavior of mineral waters in Algeria by identifying the main processes controlling water chemistry and evaluating mineral saturation states. The study included 36 mineral water samples, whose physical and chemical properties were analyzed and hydrochemically classified using the PHREEQC software and the SIT database to simulate chemical speciation and calculate saturation indices. The results show that water chemistry is mainly controlled by carbonate rock dissolution processes, whereby the majority of waters are of a calcium–bicarbonate (Ca-HCO₃) type, and saturation indices indicate supersaturation with respect to calcite and undersaturation with respect to gypsum, anhydrite, and halite, reflecting ongoing water–rock interaction processes. Some samples also show a clear influence of evaporitic formations through high sulfate concentrations and the occurrence of the calcium–sulfate (Ca-SO₄) facies. The study highlights the importance of thermodynamic modeling in understanding groundwater evolution in Algeria and in interpreting the geochemical processes controlling water quality.