Evaluation of the Potential Ecological Risk of Heavy Metal Pollution in Soil and Bioaccumulation Characteristics of Dominant Plants in Siding Pb-Zn Mineland

Soils and dominant plants were surveyed in the Siding mineland area. Based on the determination of heavy metal concentration of soil from 8 sections and 14 dominant plant species in different parts, the potential ecological risk was assessed using the Hakanson Index Method. The results indicated that the soil of Siding mineland area was seriously contaminated by Pb and Zn. The risk index values of Pb and Zn were higher than 320, and the degree of ecological hazard was extremely high. While the risk index values of Cu and Cr were lower than 40, and the degree of ecological hazard was low. Statistical analyses showed that mining and smelt activities had a great influence on the concentration and distribution of heavy metals. Pb-Zn and Pb-Cu were likely from a same source, while Cr had a different cumulating character. Furthermore, Pb, Zn, Fe, Mn, Cu and Cr in 14 dominant plant species were at different levels. But the heavy metal concentrations of aboveground part had not reached the level for hyperaccumulators. Among all the dominant plants, Phragmites australis (Cav) Trin.ex Steud., Imperata cylindrical (Linn.) Beauv., Herba taraxaci and Peris vittata L. appeared to have good accumulation of Pb and Zn, and would be very useful in the restoration of Pb and Zn contaminated areas.