Investigation of the Uptake of Heavy Metals in Waste Leachate by Vetiver from a Contaminated Soil

The aim of this study was to evaluate the potential of uptake of lead, cadmium, manganese and nickel from municipal waste leachate by Vetiver under greenhouse conditions. This research was based on a completely randomized design in three replications with four treatments, including waste leachate with concentrations of 0, 30%, 60%, and 100%. The plants were irrigated at optimum temperature conditions for vetiver (23-23 °C) and based on water requirement for 5 months and 4 watering per week, each time using one liter of leachate. The results showed that there was a significant difference at the level of 1% in the uptake of heavy metals by the plant. Also, with the increase of leachate treatment levels to 60%, there was a significant difference at the level of 1% in root and shoot length. Then, in the treatment with 100% leachate, root and shoot length were significantly reduced. With increasing levels of leachate treatment, the uptake of heavy metals by the plant increased. The highest uptake was by the root with a total average of 200.21 mg /kg in all four treatments. The highest amount of adsorption was related to manganese, lead, nickel and cadmium with averages of 70.70, 52.73, 44.56, and 32.22 mg/kg, respectively. In the shoot, the average of the total uptake of the four elements was 147.93 mg/kg, with the highest averages belonging to manganese, lead, nickel, and cadmium as 53.18, 38.35, 35.13, and 21.27 mg/kg, respectively. The maximum uptake of the four heavy metals in the roots and shoots was related to the treatment with 100%. Also, for all elements in all treatments, the biological concentration factor (BCF) was >1 and the transfer factor (TF) was <1. The results showed that the plant was able to absorb significantly higher amounts of heavy metals at higher concentrations of leachate. Since roots showed greater uptake of the heavy metals in waste leachate than shoots, vetiver plant can act as a phytostablizer and reduce heavy metals mobilization in polluted soil.