新疆准东煤田土壤重金属来源与污染评价

选择新疆准东煤田五彩湾露天煤矿为研究区,通过测定研究区内不同采样点土壤中Zn、Cu、Ni和Cr 4种重金属元素的含量,利用GIS技术和多元统计方法分析重金属的空间分布特征和主要来源,并通过降尘量分布特征和区域DEM等因素探究重金属富集的原因,最后应用地累积指数评价重金属污染等级并估算其污染范围,结果表明:Cu和Ni的浓度分布特征相似,主要来源于土壤母质,浓度分布与人为活动关系不密切.Zn除与Cu和Ni的分布特征相似外,还在煤矿区域明显集中,其来源具有多源性,不仅来源于土壤母质,也部分来源于煤矿开采时扩散的煤尘.Cr主要分布在煤矿和人为活动频繁的区域,来源于煤矿开采中的煤尘和人为的活动.在距离煤矿约7km范围内土壤受到Cr不同程度的污染,污染程度最高为中度污染,总的污染的频率为28%.煤矿区域各个单元的污染程度存在以下关系:工业区>开采区>排土场>办公生活区.Zn和Cr的区域富集除了受煤矿区域特殊地形和地貌的影响外,还与煤尘的粒径和气象因素有关.

Soil heavy metal sources and pollution assessment in the coalfield of East Junggar Basin in XinJiang

Wucaiwan open coalmine in the East Junggar Basin in XinJiang was selected as the research region, by measuring the content of soil heavy metal included Zn、Cu、Ni and Cr in different sampling point of research region, we analyzed spatial distribution characteristics and pollution source of heavy metal using multivariate statistical analysis and GIS techniques. Then we explored the causes of heavy metal enrichment through the characteristic of dust fall and DEM, and assessed the soil pollution grade of heavy metal by applying geoaccumulation index and estimated the range of pollution. The results indicate that, the content of copper and nickel in soil have the similar distribution, which comes mainly from soil parent material, and have no close relationship with human activity. The content of zinc, which is of multi-sources, is not only from soil parent material but also from the diffusible coal dust in coal mining. The chromium mainly distributes around the coal mining and human frequent activity, its content comes mainly from the coal dust and human factor. The soil suffer varying degrees of pollution for chromium in the about 7km range from open-pit coal, the maximum extent of the pollution has reached moderate polluted, and the total frequency of pollution is 28%. The pollution levels of each unit in coal have the following relationships: industrial district > mining areas > refuse dump > office and living areas. The continuous enrichment of zinc and chromium is result of the special terrain and the landscape in coal mining region, in addition to the size of coal dust and weather factor.