Author(s)

A. S. Al-Farraj, M. I. Al-Wabel, T. S. Al-Shahrani, S. E. El-Maghraby & M. A. S. Al-Sewailem

Abstract

Plant specie Rhazya stricta, which naturally grows around Mahad AD’Dahab Mine, has been selected in order to study its ability to absorb and accumulate heavy metals (Cd, Cu, Pb, Zn). Twenty four samples from roots, stems, and leaves of Rhazya stricta were collected at 0, 1, 2, 3, 4, 5, 6, and 7 km away from the landfill. Moreover, eight compost soil samples were collected from each plant site. Plant and soil samples were analyzed for total concentration of Cd, Cu, Pb, and Zn. The results showed soil contamination with respect to Cd, Cu, Pb and Zn. The concentration of those metals was very high near the landfill area (first and second locations) compared with the others. Therefore, the enrichment factor (EF) indicated very highly polluted (20 < EF ≤ 40) with Cd (33) and Zn (22) at the first location, whereas EF was 8 and 10 for Cd and Zn, respectively, at 1km away from the first location, which means a significant contamination (5 < EF ≤ 20). Furthermore, the results showed a reduction of the accumulation coefficient (AC) (<1) of heavy metals (Cd, Cu, Pb, Zn). Nevertheless, the high concentration of heavy metals in soil reflected positively on the absorption by Rhazya stricta. Therefore, Rhazya stricta, in the first and second locations, had higher concentrations of heavy metals in their roots, stems, and leaves. The study clarified that the accumulation factor for Cd, Pb, Cu and Zn was high in roots compared with stems or leaves of Rhazya stricta. The translocation factor (TF) of Cu from roots to stems was (0.76), while it was (0.63) for cadmium. However, based on (TF) from stems to leaves, heavy metals can be ordered as follows: Cd> Zn> Cu> Pb. These results indicated that Rhazya stricta might not be appropriate

Keywords

heavy metals, Rhazya stricts, Mahad AD’Dahab, Saudi Arabia, gold mining