Présentations Colloques

Session 8.04: Isotopic and residence time tracers
Moussa (orateur)
Contamination by Selected Trace Elements in Groundwater of Azzaba district in Northeast of Algeria
The region of Azzaba, located in northeast of Algeria, is geologically characterized by various mineral-bearing indices which are classified as polymetal (Pb, Zn and Cu) and mercuro-polymetallic (Hg, Pb, Zn, Cu) elements. Fifteen groundwater samples were analyzed to understand the chemical composition of the selected trace elements. The results have shown that Hg, Pb and Arsenic were identified as contaminants in almost all the groundwater samples. The bicarbonated calcic facies could be explained by the presence of cavernous limestone and calcareous sandstone of the Paleocene-Eocene age. The chlorided sodic and sulphated calcic facies were found in sandy and clayey reservoirs of Oligocene. Referring to the WHO standards, the mercury and lead norms are largely exceeded in groundwater. Geochemical modeling carried out to study the possibility of metal precipitation and the formation of the secondary ores, has shown an over saturation with regard to calcite, dolomite and aragonite+ and under saturation with respect to halite, gypsum and anhydrite. The minerals of Hg, As and Pb are under saturated in the groundwater of the study area.