Multi-isotope Approach to Study the Problem of Salinity in the Coastal Aquifer of Oued Laya, Tunisia
Geochemical and both stable (δ2H, δ18O and δ37Cl) and radioactive (3H) isotopic determinations were applied to identify the main processes involved in the increased salinization of groundwater in the Mio-Pliocene aquifer of Oued Laya, located in the eastern coast of Sousse, Tunisia. Geochemical results indicate water-rock interaction, including dissolution of evaporitic minerals, as the major process responsible for groundwater salinity. In addition, seawater intrusion is also responsible for the groundwater mineralization in this region, resulting in Cl-Na-type groundwaters and degradation of groundwater quality. The geochemical and isotopic composition of the groundwater reflects the lithological composition of the subsurface geology, the presence of salt basins (“sebkhas”), and ion exchange processes between the groundwater and clays.
KeywordsGeochemistry Salinization Coastal aquifers Isotopes Tunisia
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