Contribution à l’étude de la pollution métallique (Cd, Co, Cu, Cr, Pb, Ni et Zn) dans quatre sols agricoles de l’ouest d’Algérie et évaluation d’un test de dépollution

Abstract

We are investigating the concentrations and forms of heavy metals lead, zinc, chromium, cobalt, nickel, cadmium and copper in agricultural soils near intensive traffic areas. In two major cities in western Algeria, Tlemcen and Sidi Bel Abbes. We analyzed four soil samples (E1 and E2) cultivated with grapes, (E3 and E4) grown with wheat. The average concentration of lead, cadmium, chromium and copper in these agricultural lands exceeded the environmental quality standards of the soil in Europe. The average of total concentrations of nickel, cobalt and zinc are less than the environmental quality standards of the soil in Europe. Moreover, this is consistent with the obtained results of the contamination degrees and the potential ecological risk of a single heavy metal ( i E r ), i E r were classified as considerable (80 ≤ i E r <160), high (160 ≤ i E r <320); that, Ei r average for Pb in all soil samples is 68.67 and 162.91 for the Cd. A result, The ERI of the four soil samples provide high in all cases. When using a sequential extraction, our results show that cadmium compounds are preferentially concentrated in the carbonate fraction, Acid-extractable fraction and residual phase of the soil, causing a risk because of its high value, Co: concentrated in the phases of reducible and oxidizable. Pb, Zn, Cu and Ni are highly concentrated in the remaining two remaining phases, which are weak in reducible and oxidizable phases. These results show that these minerals are less readily available in the examined soil. Depollution test indicates that RPA has a higher potential for immobilizing MTEs, although a slight increase in water-soluble phosphate at the beginning of incubation is comparable to other treatments. The results also made it possible to verify that the application of two phosphates slightly increased the residual fractions of the MTEs and that the addition of OA had a limited effect on the distribution of the fractions of the MTEs