The Repair Effect and Accumulation Feature of Five Heavy Metals on Three Forage Grass Species in The Coalmine Wasteland

In this paper, the content of five heavy metals(Cu, Ni, Pb, Cd, Zn) were measured before and after the phytoremediation in Yingcheng coalmine wasteland, Jiutai City, JiLin Province China, by using the method of atomic absorption, and the Nemerow index method was used to evaluate the pollution intensity of the five heavy metals, in the same time, the adaptability, repair effect and accumulation feature of the three forage grass species (Melilotus suaveolens Ledeb, Medicago sativa Linn, Txifolium repens L.) were compared with each other. The results showed that the repair effect and the ability of adaptation of Melilotus suaveclens Ledeb was better, which was introduced by our Research Group and called "gold 1", two years later the pollution intensity of soil by original heavy pollution reduced to light pollution, and cadmium pollution intensity by original extremely strong pollution downed to moderate pollution with the biomass growth bigger, followed by Medicago sativa Linn, while Trifolium repens L. couldn't grow; the overall average accumulation and transformation ability of Melilotus suaveclens Ledeb were larger than Medicago sativa Linn, and increased with the extension of planted time, the accumulation and transformation ability to cadmium (Cd) and copper (Cu) of the five heavy metal elements was stronger; the accumulation and transformation ability of Medicago sativa Linn reduced with the extension of the planted time, and the accumulation ability of cadmium was stronger too, but it was poorer than Melilotus suaveclens Ledeb. The Melilotus suaveclens Ledeb. is been taken as the ideal repair plant in this study.