Etude phytoécologique des bordures de l'oued Boumerzoug et évaluation de leurs niveaux de contamination métallique (Pb, Zn, Cr, Cd et Cu)

Abstract

This study is a phytoecological analysis of the vegetation which develop on the Boumerzoug wadi banks, tributary of the Rhumel wadi. The physico-chemical characterization of the studied grounds shows a certain homogeneity between the latter, for the whole of the physico-chemical variables, except for texture. However, determination of contamination/pollution indices (C/p) revealed a slight to severe contamination, for lead and chromium, and moderated to very severe, for copper ; a contamination moderated to slight pollution, for zinc, and a slight pollution to severe for cadmium. This pollution by cadmium seems to be related as well to the urban and industrial waste as to the farming practices of the exploitations which border the wadi. The study of the vegetation of the Boumerzoug wadi banks showed that the distribution ot the plant species is influenced oy the texture of the soil and the ecological (factors, such as the raising of the banks, the distance of banks and the overgrazing. Thus, the wooded and shrubby formations extends preferably on the backs banks of the wadis, seldom flooded and most stable. The grazed pools settle as well on the borders as far from banks of the wadi, but they differ from one another in the pasture intensity which they undergo.