内蒙古包头铁矿区土壤重金属污染特征及其评价

Distribution Characteristic and Assessment of Soil Heavy Metal Pollution in the Iron Mining of Baotou in Inner Mongolia

对位于内蒙古草原生态系统的包头尾矿库区和白云鄂博铁矿开采区土壤中重金属的污染状况进行了调查研究,旨在为治理草原矿区的土壤重金属污染提供理论依据.结果表明,包头尾矿库区周围不同方向的土壤都受到了重金属Pb、Cu、Zn和Mn的污染,单项污染指数法评价表明各重金属污染程度为Mn>Zn>Pb>Cu;内梅罗综合污染指数法评价表明,尾矿区东北、东南、西南、西北方向土壤重金属综合污染指数分别为2.43、10.2、1.88、1.64,主要受包头尾矿区常年主导风向西北风的影响,处于下风向的东南方位污染最为严重;除Cu外,尾矿库区各方位土壤重金属污染最严重为距尾矿库边缘50 m范围以内的区域.对于白云鄂博采矿区,单项污染指数评价表明,调查的6个区域内土壤也都受到了重金属Pb、Cu、Zn和Mn不同程度的污染;内梅罗综合污染指数评价表明,采矿区、排土场、场区外、城区外、铁路东侧和铁路西侧区域的土壤重金属综合污染指数分别为14.3、4.30、2.69、3.41、2.88、2.20,污染程度最严重的是采矿区内的土壤,另外铁路运输矿石也已经造成了沿线土壤的重金属污染.包头尾矿库区和白云鄂博采矿区的土壤具有相似的重金属污染特征,与尾矿砂中同种重金属浓度相对应,已经对当地草原生态系统的健康稳定构成了威胁.

The pollution status and total concentration of soil heavy metals were analyzed around tailing reservoir of Baotou and iron mining of Bayan Obo located in Inner Mongolia grassland ecosystem.Aim of the study is to control soil heavy metal pollution of grassland mining area and provide the basic information.The results indicated that the soils from different directions of the tailing reservoir were contaminated by Pb,Cu,Zn and Mn.According to the single factor pollution index,the pollution degree was Mn Zn Pb Cu.According to Nemerow integrated pollution index,the indexes of the northeast,southeast,southwest,and northwest of the tailing reservoir,were 2.43,10.2,1.88,1.64.Soils from the southeast had the most serious heavy metal contamination because of the dominant wind of northwest.Within 50 m from the edge of tailing reservoir,heavy metal contamination was most serious except Cu.With regard to Bayan Obo iron mining,the single factor pollution index indicated that the soils from the six surveyed regions were contaminated by Pb,Cu,Zn and Mn.The integrated pollution index indicated that the indexes of the six regions,such as the mining area,the dump,outside the dump,outside the urban area,east region of the railway,and west region of the railway,were 14.3,4.30,2.69,3.41,2.88,and 2.20,respectively.The soil pollution degree of the mining area was the highest.Additionally,the transport of ore resulted in soil heavy metal pollution along railway.In general,soils of the two studied areas had the similar pollution characteristic,and the elements of heavy metal contamination were corresponding with the concentrations of tailings.The health and stabilization of grassland ecosystem are being threatened by soil heavy metals.