Phytoremediation of soils polluted by heavy metals using Vetiver grass and Tall Fescue

Abstract

Phytoremediation is a biological method to improve soils contaminated with heavy metals. The objective of the present research was to study the capability of Vetiver grass and Tall Fescue in refining and reducing pollution of Cd, Cu and Zn from contaminated soils. The research was implemented in greenhouse during two separate tests (Vetiver grass and Tall Fescue) in a completely randomized design including seven levels of pollution (0, 50, 100, 200, 400, 600, 800 mg kg-1 soil) from three heavy metal types (Cd, Cu and Zn) in three replications. The effects of different levels of heavy metals on the growth characteristics (fresh and dry weights) of Vetiver were not significant. Besides, the effect of cadmium levels on shoot dry weight, the effect of Zn levels on shoot fresh and dry weights and the effect of Cu levels on shoot and root fresh and dry weights in Fescue were not significant compared to the control treatment. The maximum Cd, Cu and Zn concentrations in Vetiver related to 800 mg kg-1 treatment were found as 591, 298 and 356 mg kg-1. The maximum content of Cd (96 mg kg-1), Cu (27 mg kg-1) and Zn (37 mg kg-1) in Fescue was also measured at soils polluted with 800 mg kg-1. Among different pollution treatments, Cd had the highest uptake and accumulation rate in shoot and root of plants. The results showed the higher capability of Vetiver compared to Fescue for remediation of environments contaminated with heavy metals especially Cd in Iran.