Coastal Aquifer Salinization in Semi-Arid Regions: The Case of Grombalia (Tunisia)

Groundwater resources are facing increasing pressure especially in semi-arid regions where they often represent the main freshwater resource to sustain human needs. Several aquifers Mediterranean basin suffer from salinization and quality degradation. This study provides an assessment of Grombalia coastal aquifer (Tunisia) based on multidisciplinary approach that combines chemical isotopic (?2H, ?18O, 3H, 14C ?13C) methods characterize relation between groundwater variation recharge. The results indicate total dissolved solids exceed 1000 mg/L most samples excepting recharge area. In addition water–rock interaction, evaporation nitrate pollution contributing mineralization, reverse cation exchange process constitute important mechanism controlling mineralization with enhancing risk saltwater intrusion. Environmental isotope tracers reveal is evolving within open system close system. A significant component recent water recharging confirmed by applying correction models ?13C values activities tritium contents. However, this recharge, which mainly associated return flow irrigation water, contributes salinization, for shallow aquifer.