Bioconcentration and stabilization potential studies of arsenic and some heavy metals in Astragalus gossypinus

Nowadays, soil contamination by heavy metals is one of the dangerous environmental pollutions and various methods such as phytoremediation as an environmental-friendly, simple and inexpensive method have been proposed to reduce it. Therefore, the present study was conducted to compare the capability of Astragalus spp. which grown in Markazi Province, Iran in 2016 for feasibility the introduce hyperaccumulator species. In so doing, a total of 48 soil samples and also 48 Astragalus samples were collected. After acid digestion of samples, the heavy metal concentrations were measured using ICP-OES. Also, the TF and BCF of metals were computed. The results showed that the mean concentrations of elements (mg/kg) in soil samples to be: 10.09 for As, 168.97 for Zn, 41.22 for Pb, and 50.49 for Ni. The mean contents of As, Zn, Pb, and Ni (mg/kg) in root samples were found to be 1.02, 47.87, 3.63, and 2.83 respectively, while, the mean concentrations of metals (mg/kg) in flower (aerial part) samples were 2.02 for As, 21.18 for Zn, 10.84 for Pb, and 4.03 for Ni. Based on the results, since the TF and the BCF of Zn were 0.73 and 0.52 respectively, therefore Zn mobility in Astragalus was low. While, the TF and BCF of As, Pb and Ni were > 1 and < 1 respectively, and indicates the high mobility of these elements in the plant. Thus, Astragalus spp. can be considered as a suitable species for stabilization of Zn and efficient for the accumulation of As, Pb, and Ni.