Abstract:
The first phase of the ecological restoration project of Lianhuashan mining area in eastern Guangdong is taken for a case study. The indexes of five heavy metals (As, Cd, Pb, Cu and Ni) are selected for sample collection, and the changes of standard values and background values before and after restoration are compared and analyzed to evaluate the restoration and improvement of environmental quality and ecological greening. As the research results show, the first phase of the ecological restoration project has curbed the influence of acidic mining wastewater containing heavy metals on environmental quality of downstream water. The contents of heavy metals Cu, Cd, Pb, Ni and As at the surface water monitoring point in front of the mountain were reduced by 84.1%, 86.4%, 89.4%, 90.0% and 47.7% respectively after restoration, and the reduction rate of As at the monitoring point after the mountain is greater than 98.8%. The first phase of the ecological restoration project has effectively improved the landscape of the mining area. All the 5 sample plots in the 4 ecological restoration project areas have vegetation communities formed by 3 to 5 species of plants per thousand square meters after restoration. The comprehensive index of ecological environment quality in all these areas has reached Vb, and that of No. 5 mining area is the highest, reaching 78.8% of the reference sample. The ecological restoration model of "engineering measures plus ecological regreening" adopted in the first phase of Lianhuashan mining area has produced significant effect and may provide reference for the ecological restoration of other tungsten mining areas.