Abstract

Mining activity is one of the most important sources of heavy metals in the environment. In Marrakech region, functioning or abandoned mines represent a great hazard due to huge amounts of waste deposited in waste dumps and tailings often with high concentration of heavy metals pollution. In this study, the chemical forms of four heavy metals in mine tailings of Draa Lasfar in north-west of Marrakech city (Morocco) were studied by determining of four metals (Cd, Cu, Pb, and Zn) using standard solvent extraction and atomic absorption spectrophotometric techniques. The chemical pools of the metals indicated that the metals were distributed into six fractions with most of the metals residing in the non-residual fractions, suggesting how readily the metals are released into the environment. Results showed Cd and Cu were predominantly associated with short-term mobile fraction (F1 and F2) while Pb was largely associated with long-term mobile fraction (F3, F4 and F5) and Zn was essentially bound to Fe–Mn oxide phase (F4).

Key words: Heavy metal contamination, mining activity, sequential extraction, mine tailings, Marrakech – Morocco.