Evaluation of soil pollution around Mahad AD’Dahab Mine

Abstract

Mahad AD’Dahab mine was, chosen to study its effect on the surrounding area pollution, as it was the oldest in Saudi Arabia. The objective of this study was to evaluate the degree of contamination of Mahad AD’Dahab soil with respect to heavy metals (As,Be, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Ti, V, Zn and Hg). One hundred thirty nine soil samples representing three depths from 55 location around the mining area were collected from a transect (0– ≈12 km) closed to the mining area. The collected samples were prepared and analyzed for their contents of above metals. The obtained results indicate that the soils of study area are so much loaded with heavy metals. The total concentrations of heavy metals indicated that most soil samples were significantly polluted (99 %) with one metal or more based on the Enrichment Factor (EF). While the percent of high polluted and very high polluted soil samples were 46 & 33% respectively. Moreover, the physical barriers (e.g. mountains) minimized the hazard of soil heavy metals pollutions. As the EF was > 40 in 41% of the surface soil samples (0–15 cm). While the respective values reached 27 and 23 % in the sub surface layers (15–30 cm) (>30 cm) soil samples, respectively. The concentrations of the studying heavy metals could be arranged in the following order: Cd> Hg > Pb > Zn> Cu > As >Mo >Be. Comparing the obtained results with the international guidelines such as (Scotland, Holland & Chinese), data indicate that, the soil samples were polluted with Cu, Zn, Pb, Cd, Hg & As. Also, the calculated coefficient of variation (CV) shows that the soils of the studying area were highly polluted with heavy metals in the following order: Cd> Zn> Pb> Hg> Cu> Mo. In conclusion, all results indicate that the mining activities at Mahad AD’Dahab were positively contributed to the soil heavy metals pollution in such area. Because of the pollution level reached a dangerous degree, especially in the western area, environmental impact assessment must be applied to minimize the negative effects of heavy metals pollution resulted from industrialization and mining activities under Saudi Arabian conditions