淮南煤矿复垦区土壤重金属含量分布及潜在生态风险评价

Distribution and Potential Ecological Risk Assessment of Soil Heavy Metals in Reclaimed Land in Huainan Coal Mine

以淮南矿区煤矸石充填复垦地为研究对象,对该复垦区不同土地利用方式(小麦地、桃林、蔬菜大棚、油菜地)下土壤Cd,Zn,As,Ni,Cu,Pb,Cr,Mn共8种重金属含量进行了分析和评价。结果表明,相对土壤背景值,该复垦区土壤中Zn,Cr,Mn,As污染较为严重;相对未复垦区,复垦区土壤中的Zn,Cd,As分别是未复垦区的4.38,2.57和2.20倍,具有明显的累积现象。不同土地利用方式土壤重金属含量差异较大,小麦地和桃林地的Zn,Cd,As含量远大于油菜地和蔬菜大棚,Cr含量则表现为桃林地、蔬菜地远大于小麦地和油菜地,Ni,Cu,Mn,Pb在4种土地利用类型下的差异不显著。土地利用方式、施肥以及受采矿活动的影响程度不同是导致土壤重金属含量差异的主要原因。淮南煤矿复垦土壤中各重金属的生态风险顺序为:Cd>Zn>As>Ni>Cu>Pb>Cr>Mn。Cd的潜在生态风险值最大(89.71),属于强生态风险,其余元素均为轻微风险。不同土地利用方式的风险顺序为:小麦地>桃林地>蔬菜大棚>油菜地。

Samples collected around reclamation land of Huainan coal mine were analyzed on the concentration of heavy metals（Cd, Zn, As, Ni, Cu, Pb, Cr, Mn） in the soils under different land use patterns（wheat field, peach oehard, vegetable greenhouse and rape field）. The results showed that the concentration of heavy metals Zn, Cd and As in soil from reclaimed coal mine was 4.38,2.57,2.20 times of reference soil and there was a rather large difference of the accumulation of soil heavy metals under different land use patterns. The concentration of Zn, Cd, As in wheat field and peach orchard are higher than that in the vegetable green- house and rape field. The Cr concentration in vegetable greenhouse and peach orchard are higher than that in the wheatland and rape field. The difference of concentration of heavy metals of Ni, Cu, Mn, Pb under dif- ferent land use patterns was not significant. Land use types, fertilization and coal mining activities were the main reasons leading to the difference of heavy metals concentration in soils under different landuse patterns. The order of soil heavy metals concentration risks in soils is as Cd〉Zn〉As〉Ni〉Cu〉Pb〉Cr〉Mn while the highest is the Cd concentration in reclaimed soi1（89.71）. The ecological risks in different land use pat- terns is as wheat feild〉peach orchard〉vegetable greenhouse〉rape field.