This paper is about groundwater’s quality in Ghassira which is located in El-Abiod valley in eastern Algeria. The water is used for human consumption and irrigation. The different layers belong to several types of rocks (limestone and evaporate ...). To study the behaviour   of dissolved salts in this water, we have used geology of the aquifers and statistics. This combination gives us information about minerals those are responsible of water’s quality.  80% of analyzed samples are influenced by evaporate rocks (gypsum, halite…) and 20% by limestone. Many processes have generated these two classes and are relating, especially, with the rocks of aquifers.

Ain Djacer Area is the seat of an aquifer which is located in the alluvial deposits of Mio-Plio-Quaternary. This groundwater has to bedrock clays and gypsum marl Miocene, is surrounded by Cretaceous limestones which are limited to a fixed potential. It is a synclinal filled by sediments Mio-Plio-Quaternary where all flows converge toward the center of the plain. The intensive exploitation of groundwater resources in the region has greatly influenced the hydrodynamic and hydrochemical functioning of the shallow aquifer. This caused a decrease in the static level and mineralization of groundwater. To demonstrate the effect of this situation on the quality of groundwater, a hydrogeochemical study was conducted. This study showed that the calcium bicarbonate facies is near limestone and sodium chloride concentration in the center of the plain in liaison with the lithology. The thermodynamic analysis showed that the main geochemical processes involved in the acquisition of saline load are related to water-rock interaction (dissolution of carbonate and evaporate minerals), the cation exchange and concentrating along flow.