Pan Yuxue, Li Haitao
Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, A11 Datun Avenue, Chaoyang District, Beijing, 100101, China.
Environ Manage. 2016 Apr;57(4):879-93. doi: 10.1007/s00267-016-0658-6. Epub 2016 Jan 20.
The rapid urbanization of China and associated demand for land resources necessitates remediation, redevelopment, and reclamation of contaminated soil. Before these measures are taken, a basic investigation and inventory of heavy metal (HM) pollution levels in contaminated soil is necessary for establishing and implementing the redevelopment plan. In the present study, to identify the policy implications of inventorying and mapping HM pollution of soil in brownfields throughout China, the Bayan Obo giant rare earth element (REE)-Nb-Fe ore deposit of Baotou in Inner Mongolia, China, which is the largest REE mineral deposit in the world, was taken as a case study. Soil samples from 24 sites in Bayan Obo mining area (MA) and 76 sites in mine tailing area (TA) were collected for determining contents of soil HMs (Cr, Cd, Pb, Cu, and Zn). The results showed that the average concentrations of Cr, Cd, Pb, Cu, and Zn in both MA and TA were all higher than their corresponding background values for Inner Mongolia but lower than the Class II criteria of the National Soil Quality Standards of China (GB 15618-1995). Enrichment factor (EF) analysis of the soil samples indicated that the soil in the brownfield sites was highly enriched with Cr, Cd, Pb, Cu, and Zn compared to the corresponding background values. In MA, the EF for Cd was the highest among the studied elements, while in TA, the EF for Cr (3.45) was the highest, closely followed by the EF for Cd (3.34). The potential ecological risk index (RI) indicated a moderate potential ecological risk from the studied HMs in MA and a low potential ecological risk in TA, and the results of RI also suggested that the soil was most heavily polluted by Cd. According to the spatial distribution maps of HM, contamination hot-spots were primarily located near mining-related high-pollution plants. Based on the results, policy recommendations are proposed related to brownfield management in urban planning.
中国快速的城市化进程以及对土地资源的相关需求，使得对污染土壤进行修复、再开发和开垦成为必要。在采取这些措施之前，对污染土壤中的重金属（HM）污染水平进行基本调查和清查，对于制定和实施再开发计划至关重要。在本研究中，为了确定中国各地棕地土壤中重金属污染清查和绘图的政策含义，以内蒙古包头的白云鄂博巨型稀土元素（REE）-铌-铁矿床为例进行研究，该矿床是世界上最大的稀土矿床。采集了白云鄂博矿区（MA）24个地点和尾矿区（TA）76个地点的土壤样本，以测定土壤中重金属（铬、镉、铅、铜和锌）的含量。结果表明，MA和TA中铬、镉、铅、铜和锌的平均浓度均高于内蒙古相应的背景值，但低于中国国家土壤质量标准（GB 15618-1995）的二级标准。对土壤样本的富集因子（EF）分析表明，与相应背景值相比，棕地土壤中铬、镉、铅、铜和锌高度富集。在MA中，镉的EF在所研究元素中最高，而在TA中，铬的EF（3.45）最高，紧随其后的是镉的EF（3.34）。潜在生态风险指数（RI）表明，MA中所研究的重金属存在中等潜在生态风险，TA中存在低潜在生态风险，RI结果还表明土壤受镉污染最严重。根据重金属的空间分布图，污染热点主要位于与采矿相关的高污染工厂附近。基于这些结果，提出了与城市规划中棕地管理相关的政策建议。
