矿区充填复垦土壤重金属分布特征研究

为保证矿区种植农作物的充填复垦土地的生态安全,以徐州柳新矿区粉煤灰、煤矸石充填以及对照场地为研究区,通过对3块场地中As,Cd,Cr,Cu,Hg,Pb,Zn 7种重金属元素不同深度含量分析,总结7种重金属纵向的分布情况,并将3块场地重金属含量与土壤背景值、土壤环境质量标准做比较,分析7种重金属元素的变化度和污染程度.结果表明:3块场地中,相对于土壤背景值,Hg,Cu,Cd,Pb的变化度均较大;煤矸石场地的Zn变化度偏大;As,Cr的变化度均较小.相对于土壤质量评价标准,Cd均超过土壤质量标准;除极少数As,Zn,Cu样点超标,其余均未超标.在此基础上,对Cd进行详细分析,以粉煤灰场地为例,建立了Cd纵向分布的克里格模型,所建模型拟合精度较高.研究结果将为矿区污染土地的修复并进而制定相应治理措施提供依据.

Distribution of Heavy Metals in Reclamation Soils of Mining Area

To keep the ecological safety of reclaimed lands by filling mining wastes and fly ash into subsided lands used as agricultural purpose, we took Liuxin mining area, Xuzhou in Chi- na, as the research area, and the contents of heavy metals As, Hg, Pb, Cu, Cd, Cr and Zn in different soils, including reclaimed soils and control soil with different depths, were tested and compared with control soil. Based on that the serious Cd pollution was mainly studied. The results show that: relative to the Xuzhou soil background value, the variation degree of Hg, Cu, Cd, Pb is great; the variation degree of Zn in gangue is also great. The variation degree of As, Cr as well as fly ash site, control soil is little. Refer to the China soil quality standard, all Cd. Samples surpass the standard; with the exception of few samples of As, Zn and Cu, others do not exceed the standard. Taking Cd distribution in fly ash site as an example, the polynomial fitting model was used to describe its change regularity with depth and the fitting equation is feasible. Besides, the Kriging Model was applied to investigate the Cd distribution regulation. The built models show high fitting precision and the research results above will provide foundations for rehabilitating the polluted land in mining area and then setting corresponding measures.