Heavy Metals Distribution in Soils of an Agricultural Area Impacted by Former Mining Activities: Case of Trozza Mine, Tunisia

Abstract

Mining waste management is currently a major environmental concern due to the presence of high concentrations of potentially toxic metals (Pb, Zn, Cd, among others) in the surroundings of old mining areas. The large quantities of tailings are a direct cause of serious metal contamination, which is a threat to the environment as well as human beings. The decommissioned Jbal Trozza mine in Kairuan (Tunisia) is considered a serious problem, and in order to evaluate the distribution of metals contents in the mine area, tailings and soils samples were collected in the vicinity of the mine. The mine tailings are characterized by high levels of Pb (1830–5950 mg.kg−1), Zn (7590– 12480 mg.kg−1 ) and Cd (85.95–123.25 mg.kg−1). The adjacent soils were also highly contaminated with metals. The results show that the average concentrations of Pb, Zn and Cd in the soil of the mine area clearly exceed the Tunisian standard values in agricultural areas (100 mg. kg−1 for Pb, mg.kg−1 for Zn and 3 mg.kg−1 for Cd).