Evaluating the heavy metals-associated ecological risks in soil and sediments of a decommissioned Tunisian mine

Abstract

There is no doubt that mining activities result in a serious threat to the environment. This study dealt with the heavy metals pollution and ecological risk assessment of the former Jebal Ressas mining site on soils and surrounding sediments. Twenty soil samples were gathered from around the mining discharges and agricultural land, and six sediment samples were collected from Wadi Hmma. Then the trace metal elements Pb, Zn, Cd, As, Ni, Cr and Cu concentrations were determined for these samples. The analyses revealed the presence of the heavy metals (Pb, Zn, Cd and As) in the soil for most of the samples, mainly those close to the mining waste. The Pb, Zn, Cd and As concentrations were remarked to exceed the respective local geo-geochemical backgrounds, indicating an anthropogenic source of pollution. However, the weak presence of Ni and Cr with Fe, not exceeding 3, in these soils reflect the natural origin of these elements. The ecological risk potential index study results unveiled that the Cd content has a significant potential ecological risk.