Assessment of mining soils metallic contamination in a semi-arid environment

Hajar Benmazhar, Nadra Lekouch, Azedine Sedki

Résumé


The environmental pollution due to the abandoned mining sites is now, indubitably, one of the main concerns of the environmentalists worldwide. Mining waste with elevated trace elements charge has a severe impact on the soil. Furthermore, the semi-arid climate only seems to aggravate the barely vegetated soil’s condition, customarily with its intense rainfall that eventually leads to the problematic acid mine drainage phenomenon. The purpose of this research is the assessment of trace elements contamination in the soils of three abandoned mining sites in a semi-arid region. Therefore, we have conducted a broad sampling sets of soil, and waste in the different mining zones; Freg Al Ma, Roc Blanc, and Bir Nhas. The samples were collected every single month, throughout a whole year in the upstream, downstream, and nearby the mining waste. After their digestion with acidic products, the samples were analyzed using the Atomic Absorption Spectrometry (AAS). According to our findings, trace elements’ concentrations in the mining soils have all exceeded the WHO/FAO thresholds; Freg Al Ma (Zn= 310.3 ppm, Cu=112.8 ppm, Pb=114.6 ppm, Fe= 474.1 ppm), Roc Blanc (Zn= 490.3 ppm, Cu=324.7 ppm, Pb=243.4 ppm, Fe=3209.2 ppm), Bir Nhas (Zn= 682.1ppm, Cu=523.3 ppm, Pb=398.5 ppm, Fe=4476.8 ppm).The mining waste appears to be the main source of the soil’s contamination, merely due to the cluster of trace elements it discharges into the environment, especially during the rainy season.

Mots-clés


Abandoned mining sites, Soil pollution, Trace elements, Semi-arid environment

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