ENVIRONMENTAL POLLUTION FROM HEAVY METALS IN SOILS SURROUNDING THE ABANDONED MINE OF TANSRIFT (CENTRAL HIGH-ATLAS, MOROCCO)

Abstract

In this study, the heavy metal (HM) pollution status, possible sources, and potential ecological and health risk of heavy metals in soils around the Tansrift abandoned mine (Central High Atlas, Morocco) were investigated using the coefficient variation (CV), principal component analysis (PCA), enrichment factor (EF), geoaccumulation index (Igeo), Pollution Load Index (PLI), potential ecological risk index (RI), and total hazard index (HI). A total of 25 surface soil samples were collected and analyzed to determine the soil proprieties of magnetic susceptibility (MS), organic matter (OM) contents, texture, and the HM (Cd, Cr, Cu, Pb, and Zn) concentrations. The average metal concentrations of 7.74 (Cd), 64.19 (Cr), 333.59 (Cu), 29.95 (Pb), and 58.12 (Zn) mg/kg in soils are higher, except for Pb, than that of the local background and worldwide guidelines. The MS result showed that the soil magnetic material consisted of multidomain (MD), superparamagnetic (SP), and stable single domain (SSD) particles, which were derived from both natural and anthropogenic sources. Moreover, the statistical analysis indicated that Cu originated mainly from anthropogenic and lithologic sources such as agricultural practices, soil parent materials, and mineral dust and wastes from the Tansrift mine. In contrast, agricultural activities are the predominant origin for Cd, Cr, and Zn. EF values revealed a significant HM contamination of samples soils, which is in the order of Cd>Cu>Cr>Zn>Pb. The Igeo and PLI results attested that soils were significantly affected by Cd, Cr and Cu toxic metal and, to a lesser degree, by Pb and Zn. According to the RI levels (12.07-1540.37), 40% of sampling sites were at considerable to high ecological risk, mainly influenced by Cd and Cu. Based on the HI values, the non-carcinogenic risk of HMs in studied soils could be neglected for adults but not for children. These findings showed the adverse HM effects on the environmental quality of soils and the need to implement protective management strategies in the study area.