Evaluation of phytoremediation potential of lead and cadmium in rangeland plant species, Dactylis glomerata, Festuca ovina and Medicago sativa

Potentially toxic elements (PTEs) contain two classes of essential and non-essential elements that are significant in toxicological ecology. These elements have high stability and have the ability to cause toxicity in living organisms. Phytoremediation has been considered as one of the most appropriate and efficient methods to uptake these elements. The aim of this study was to investigate the ability of different forage species to absorb PTEs and to be aware of the compatibility and resistance of each to contamination, a comparison between species with different biological conditions. This study was performed in a greenhouse environment and Dactylis glomerata, Festuca ovina and Medicago sativa species were considered. To measure PTEs (lead and cadmium), dry ash extraction method was used. Also, to determine the phytoremediation potential of plant indices TF, BCF and BAC were used. To compare the data statistically, multivariate analysis of variance test in the form of general linear model was used and for multiple comparison of means, Duncan test was used. The results showed that D. glomerata with increasing concentrations of lead (200 to 800 mg/kg) and cadmium (50 to 200 mg/kg) increased their concentration in shoots and roots by about 84% and 86%, respectively in the shoot and root. The root uptake of M. sativa increased with increasing lead concentration, and as a result, M. sativa is an extractive plant for both cadmium and lead. In Festuca ovina species, with increasing lead concentration, the rate of uptake by roots and shoots was 70% and 58%, respectively, and for cadmium was 79% and 73%, respectively. In general, in the studied species, the efficiency of phytoremediation of lead was higher in the aerial parts to the root, but cadmium of the roots of D. glomerata and F. ovina, had more phytoremediation efficiency than the aerial parts.