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

Abstract

Abstract: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 CaCO 3 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.

Evaluation of the impact of mine activity on surrounding soils of Draa Lasfar mine in Marrakech- Morocco

“…Draa Lasfar mine involves a deposit of pyrite located 10 km northwest of Marrakech city ( Figure 1) that can pose a risk to the environment due to tailings discharges surrounding the mine area (Avila et al, 2012).…”

Study of potential environmental risk of trace metallic elements in mine tailings: Case of Draa Lasfar functional mine in Marrakech - Morocco

“…The sequential extraction was performed using five-step procedure (Fuentes et al, 2004). Additionally, a sixth step was added, which consisted of dissolving the final residue using the same digestion procedure for the total metal determination (Gleyzes et al, 2002;Avila et al, 2012). (F5) Organic-Bound: The residue from Fe-Mn oxides bound fraction was extracted with 3 ml of 0.02M HNO3 and 5 ml of 30% H2O2 (adjusted to pH 2 with HNO3) was added and the mixture heated to 85°C for 3 hours, with occasional agitation.…”

Heavy metals speciation to study mining activity impact on surrounding soils: Kettara mine, Marrakech – Morocco

“…Sequential extraction was used to assess heavy metal speciation in the samples, utilizing a five-step procedure [22] . Additionally, a sixth step was added to dissolve the final residue, using the same digestion procedure, for the determination of total metal [11] .…”

“…In mining areas, high levels of heavy metals can accumulate in nearby agricultural soils, food crops and watercourse systems due to the release and dispersal of mining waste [8][9][10] . This presents a potential health risk to residents living close to mining areas [10,11] . The intensive mining activity in the Marrakech region poses a significant danger due to the large quantities of heavy metals that are released into the environment.…”