Heavy Metal Contamination and Mobility at the Mine Area of Draa Lasfar (Morocco)

The present study represents a first insight into the Draa Lasfar mine (Marrakech) to assess the possible diffusion of heavy metals and to predict the risk of their mobility in the surroundings of the mine area. The edaphologic parameters pH, electrical conductivity (EC), loss on ignition (LOI) and CaCO3 were measured according to standard methods, whilst heavy metals concentration was determined by FP-XRF. Concentration enrichment ratios (CER) were calculated in order to estimate the anthropogenic contribution of target pollutants determining As, Cu, Pb and Zn as the main pollutants, whereas Ba, Ca, Fe, K, Mn, Rb, Sr, Ti and Zr were considered lithogenic components. GIS contour maps of pollutants using CER data, showed the most polluted areas at the vicinity of the mine, especially at the northwest area, probably linked to weathering effects and topography of the area. Particle size studies revealed that As, Pb and Zn are part of the mineral ore while Cu behavior corresponded to an anthropogenic origin. Additionally, mobility assays employing single leaching tests indicated a greater mobility of As and Zn rather than that of Pb and Cu due to their lower adsorption process in the soil, independently of their respective concentration.