Heavy metal contamination of soils from abandoned mines: The case of Aouli-Mibladen-Zeïda mines in Morocco

This study assesses the metal contamination of soils in the vicinities of Aouli, Mibladen and Zeïda mines abandoned in the High Moulouya in eastern Morocco focusing in particular on its spatial variability as well as on the extent of the contaminated area. The results show that the studied soils close to mining sites and even very remote are highly contaminated with heavy metals: Pb, Zn, Cu and Cd. The results also highlight great variability in concentrations between soils of the three mining sites as well as at the same mining site. The index of soil pollution is generally high even for soils sampled downstream located at more than 130 km from the mining sites, while surface levels on tailings are extremely high, indicating that they are perennial sources of contamination by heavy metals. The insalubrious area affected by metallic pollution derived from the abandoned mining sites in the high Moulouya is very large due to dispersal by wind and water transport of metallic pollutants of mine tailings. Remedial measures must be taken to immobilize pollutants and limit their transport to the environment.