Investigation of sulphate origins in the Jeffara aquifer, southeastern Tunisia: A geochemical approach

Abstract

The chemical composition of groundwater within the multilayer Jeffara aquifer and the detailed analysis of saturation indices enables identification of the origin of mineralization and hydrogeochemical processes occurring in groundwater. It has been demonstrated that groundwater is mainly characterized by a Ca-Mg-SO 4-Cl water type. Geochemical pattern is controlled by the dissolution of evaporites, largely abundant in the study area and incongruent dissolution of dolomite. Gypsum, anhydrite, mirabilite and thenardite have been examined as potential sources of sulphate dissolved in groundwater. Since Jeffara groundwater is recharged by the Continental Intercalaire (CI) geothermal water, water temperature decreases from the CI to the Jeffara aquifer. Solubility of the majority of minerals is modified by this change in temperature and thus a mixing process of thermal and non-thermal waters was examined.

Temporal hydrogeochemical evolution of karst groundwater discharging into a continental-type Ramsar site in the Huasteca Potosina, Mexico

“…The rst component represents the ows that have remained in the subsoil for a longer time, including elements such as Li + , F − , characteristic of groundwater ows that have had a longer travel time and depth, giving them enough time in the subsoil to increase their concentration (Carrillo-Rivera, et al, 2002). Also in this same classi cation we nd elements such as Ca 2+ and Mg 2+ , whose increase is, as mentioned above, related to the dissolution of evaporite minerals; in this case gypsum (Edmunds et al 1997;Kamel et al, 2013), which is grouped in this same factor. The EC associated with this is an indication of groundwater ows that have experienced longer water-rock interaction.…”

Arsenic, barium, strontium and uranium geochemistry and their utility as tracers to characterize groundwaters from the Espadán–Calderona Triassic Domain, Spain

“…In the study area, the most likely sources of strontium are sulfate salts, present as celestine (SrSO 4 ) or gypsum/anhydrite containing trace concentrations of this element, as suggested by other authors for similar geological scenarios (Edmunds et al, 1997;Kamel et al, 2005Kamel et al, , 2013. The relationship between strontium and barium in groundwater is controlled by the dissolution of sulfate salts containing strontium and the precipitation of barite.…”

Hydrochemical Characterization and Water Quality of the Continental Intercalare Aquifer in the Ghardaïa Region (Algerian Sahara)

“…SO 4 2correlation (Fig. 4e) shows a proportional evolution of sulfate and sodium (r = 0.89), indicating another origin of sulfate than gypsum and anhydrite, namely the dissolution of thenardite (Na 2 SO 4 ) ( Kamel and al., 2013). The good correlation between Mg 2+ and SO 4 2-(r = 0.87) suggests that some of the SO 4…”

“…(2) Calculate the quality rating scale for each of the parameters considered. The quality assessment scale (qi) is calculated by equation 8: qi= (ci/si)*100 (8) where: qi is the quality rating scale, Ci is the concentration of the respective chemical parameter in each water sample in mg/l, and Si is the Algerian standard for drinking water (Table 3).…”