Assessment of heavy metals contamination in soils around a mining site in Marrakech region, Morocco

Mining sites are a permanent toxicological problem for the surrounding ecosystems and human health. In the present study we investigate the accumulation of heavy metals in agricultural soils collected from the surrounding area of a mining site of Marrakech (Morocco). The occurrence of heavy metals in field soils was, in a decreasing order, Zn > Cu > Pb and Cd. Concentrations of the heavy metals were higher in the studied soils compared to the control soil. Based on the geoaccumulation index (GeoI) and the contamination factor (CF), the contamination degree can be defined as slightly contaminated for Pb and Zn, highly contaminated for Cd and moderately contaminated for Cu. With respect to the pollution load index (PLI) the metal levels exceed local and regional background concentrations indicating contamination sufficiently high to attract attention and to pose risk to the ecosystem. Heavy metals are persistent in the environment and are subject to bioaccumulation in food chains and therefore pose substantial health risks for human and animal.