Citation:
Abstract:
: This paper is a contribution to evaluate the physicochemical characteristics of the groundwater of Merdja Zana-Chott Saboun. The study of geology with the geophysics highlights the existence of two formations aquifers. The first surface formation, formed by levels of sand, gravel, limestone and clay intercalations, dating to the age of the Mio-PlioQuaternary. The second formation is carbonated and formed primarily by limestones of the lower Cretaceous and superior Jurassic. The covering of surface reaches, in certain places, 150m of thickness in particular near the Chott and a low thickness in the vicinity of the mountains. T: This Thist t t he multivariate statistical techniques, were used to identify the hydrochemical processes and their relation with groundwater quality and to get an insight into the hydrochemical Chott Saboun aquifer groundwater chemistry evaluation. Twenty five samples are analyzed. The Piper diagram showed that water facies are magnesium bicarbonate on the sides of the western reliefs and magnesium chloride-sulphated at the north and the center of the plain. The PCA carried out on three factors revealed that on the factorial design F1-F3, nitrates negatively determine factor 3, indicating the presence of an agriculture pollution. On the factorial design F1-F2, HCO3 - negatively determine the factor 2, indicating the carbonated origin. However, the CA, based on variables, showed that the waters in the region can be classified into three groups according to flow direction while, the CA, based on major ion contents, defined three groups, reflecting the same hydrochemical facies. The first group characterized by Mg2+ and Cl- , HCO3 - . Samples of this group are mostly located in the north and northeastern part of the region. The second group characterized by Mg2+ and SO4 --, Clis located near the Northwestern and western outcrops. The third group coincides with the central part, the lowest of the plain, characterized by Mg2+ and SO4 --. The hydrochemical study made it possible to allot the evaporitic origin to the elements Na+, Mg2+ , K + , Cl- , SO4 - , while for element HCO3 - it results from the carbonated formations. These results showed that the presence of nitrates in the studied area is closely linked to the agricultural activity.