Evaluation of the Speciation of Heavy Metals (Cd, Pb, Zn, Cr and As) in the Different Horizons of an Agricultural Soil

This research has enabled the assessment of environmental risk related to potential transfers of metal trace elements such as lead, cadmium, zinc, chromium and arsenic in agricultural soils whose cultivation is nearby barley. From the industrial discharge of the technical discharge center (CET) of the municipality of Oued El Djemaa is located in the Wilaya de Rélizane-Algeria and close to solid domestic waste from industrial discharges. To meet this main objective, several analyzes were carried out, based on the first place on the chemical extraction of heavy metals by treating water. This extraction has highlighted a fairly strong accumulation of cadmium, arsenic and zinc in the soil. If the total levels of heavy metal by lawy water allow for a first state of fixtures, it is more specified according to the method of Tessier which has allowed an estimate of the future of pollutants and a risk approach. The sequential extraction on the ground showed a significant source of pollution by cadmium which is mainly related to the carbonates that makes it mobile and which constitutes a potential threat to the environment. On the other hand, arsenic and zinc are mainly related to the residual phase and the reducible phase respectively so they are little mobile in the soil and do not show threat. This research work has made it possible to access fine knowledge of the fate of metal pollutants (Cd, Pb, Zn, Cr and As) in agricultural soil. He also highlighted shadow points requiring multidisciplinary research.