Study on the contents of heavy metal in soil and vegetation in filling reclaimed land in Xuzhou Jiuli mining area

Abstract

To keep healthy, steady and sustainable utilization of reclaimed lands by filling mining wastes and fly ash into subsided lands, five heavy metals including Cd, Cu, Pb, Cr and Zn were analyzed. The potential ecological risk and pollution degree of the heavy metals were evaluated by using Hakanson ecological risk index in reclaimed land filled with fly ash and coal gangue. In order to know heavy metals in reclaimed lands by filling mining wastes and fly ash, we survey the wheat grow up on reclaimed lands by filling mining wastes and fly ash. The results show that the entire research area is contaminated by heavy metal, especially by Pb. The average of composite pollution exponent is 7.85, pollution degree is higher, and the ecological risk index is 68.69, risk degree is higher in reclaimed soil filled with gangue. The average of composite pollution exponent was 2.74, pollution degree is low, the ecological risk index is 23.24, and risk degree is at low in reclaimed soil filled with fly ash. Crops growed up on reclaimed lands by filling mining wastes and fly ash was affected by heavy metals, to some degree, etc. The Pb content in crop exceeds the allowed figure seriously.