Uptake of Trace Metals by Imperata Cylindrical in Pot Experiments with Mafic Tailings and its Significance for Phytoremediation

Mafic tailing is one of the common tailings in China which appears around metal-bearing mines with ultrabasic and basic rocks. These tailings are enriched in Cr, Ni, Cu, Mn and Zn comparing with other tailings.Phytoremediation is a method which can remove or reduce trace metals by plant uptake in tailing yard. This paper studies the concentration changes of Cr, Ni, Cu, Mn and Zn in mafic tailings of experiment pots and bioaccumulation during Imperata Cylindrical growth. The results indicate that serpentine-type tailings are more suitable for the growth of plants due to their completely weathering and higher organic matter than other tailings. The concentration of Ni is higher than other metals in Imperata Cylindrical and Ni in root is more easily transfer to leaf. The acid-soluble form percentages of Ni, Zn, Cu and Cr decrease after experiments which show these metals in tailings are absorbed by Imperata Cylindrical. But reducible-Mn significantly decreased after pot experiments. Based on experimental results, all metals studied in rhizosphere-influenced tailings are more stable than bulk tailings which indicate that the ecological risks of trace metalsdecrease after the phytoremediation of Imperata Cylindrical.