湖北某矿区土壤重金属污染状况研究

发布时间：2018-05-03 00:18

本文选题：矿区 + 土壤　；参考：《武汉工程大学》2015年硕士论文

【摘要】：埋藏于地下的矿物由于矿山的开采和冶选而暴露在地表环境中,使土壤原有的环境结构和状态产生巨变,采选过程中重金属元素通过污水灌溉、大气降尘、尾渣扬尘或淋溶等方式进入周围环境,当土壤中重金属元素的含量超过土壤的自净能力时,就会造成土壤重金属污染。土壤重金属污染不仅会严重危害生态环境和人体健康,还会对矿产采选行业的发展产生阻碍。因此,对矿区土壤重金属污染状况进行研究的重要性日益凸显,矿区的生态重建和环境污染修复问题也日益迫切。论文以湖北某矿区为重点研究对象,根据矿区不同功能分区系统采集土壤样本,采用原子吸收分光光度计等设备进行重金属含量的室内测定,以此为基础分析矿区土壤重金属污染特征及污染规律,并采用内梅罗指数法、地累积指数法、模糊数学法分析评价矿区土壤重金属污染程度,以及潜在生态危害指数法评价矿区的潜在生态风险。结果表明,矿区土壤中Cu、Zn、Pb、Cd、Ni五种重金属元素的含量平均值均超过湖北省土壤背景值,其中Cd含量均值超出背景值79倍多,矿区土壤已经受到了以Cd为主的重金属污染,污染程度十分严重。选冶区南侧的污水处理站下游方向和尾矿库下游的土壤样品中重金属Cu、Zn、Pb、Cd、Ni含量均明显增高,说明选冶区和尾矿库区对矿区土壤中重金属含量的贡献较大。Cu、Zn、Pb、Cd4种元素显著相关,可以说明这四种元素来源相同,主要来自于矿区选冶区的矿石冶炼过程和尾矿库的尾渣堆积。矿区工业场地、选冶区、尾矿库区和办公生活区均存在不同程度的土壤重金属污染现象,其中工业场地的道路运输区域、选冶区的污水处理站下游以及尾矿库区下游为重金属富集较严重的区域。内梅罗指数法表明,以湖北省土壤环境背景值和国家土壤环境质量三级标准分别作为评价标准,评价结果显示湖北某矿区40个采样点的土壤样品均已达到重污染程度。地累积指数法显示,不论是各点位单个重金属元素还是各重金属所有点位的平均值,重金属Cd的污染指数均为最高,对矿区土壤的污染贡献最大。矿区土壤的模糊综合评价结果表明,矿区土壤环境污染为严重污染级别,土壤重金属污染问题亟待解决。矿区土壤重金属污染的潜在生态风险评价表明,Cd危害矿区生态安全的潜在风险很大,整个矿区的生态风险程度较强。综合四种评价方法可以看出,矿区已受到以Cd为主的重金属污染,重金属污染较严重的区域为选冶区下游和尾矿库区下游。
[Abstract]:Minerals buried underground are exposed to the surface environment because of mining and metallurgical separation of mines, resulting in great changes in the original environmental structure and state of the soil. Heavy metal elements are irrigated by sewage and dust fall in the atmosphere during the process of mining and dressing. When the dust or leachate of the tailings enters the surrounding environment, the heavy metal pollution will occur when the content of heavy metal elements in the soil exceeds the self-purification ability of the soil. Soil heavy metal pollution will not only seriously harm the ecological environment and human health, but also hinder the development of mineral mining industry. Therefore, the importance of studying heavy metal pollution in mining area is becoming more and more important, and the problems of ecological reconstruction and environmental pollution remediation in mining area are becoming more and more urgent. This paper focuses on a mining area in Hubei province. According to different functional zoning systems of mining area, soil samples are collected, and heavy metal contents are measured in laboratory with atomic absorption spectrophotometer and other equipment. On this basis, the characteristics and laws of heavy metal pollution in soil of mining area were analyzed, and the degree of heavy metal pollution in mining area was analyzed and evaluated by Nemero index method, ground accumulation index method and fuzzy mathematics method. And potential ecological hazard index method to evaluate the potential ecological risk in mining area. The results showed that the average contents of five heavy metals in the soil of the mining area were all higher than the background value of Hubei Province, and the average of CD content was more than 79 times higher than the background value, and the soil of the mining area had been polluted by heavy metals mainly of CD. The pollution is very serious. The lower direction of sewage treatment station on the south side of the dressing and smelting area and the content of heavy metal Cu ~ (2 +) Zn ~ (2 +) Pb ~ (2 +) CD ~ (2 +) in the soil samples of the lower reaches of the tailings pool are obviously increased, which indicates that the contribution of the heavy metal content to the soil of the mining area is greater in the dressing and smelting area and the tailings reservoir area, and there is a significant correlation among the four elements. It can be concluded that these four elements come from the same source, mainly from the ore smelting process and tailings accumulation in the ore dressing and smelting area. Industrial sites, dressing and smelting areas, tailings storage areas and office living areas all have different degrees of soil heavy metal pollution, among which the road transportation areas of industrial sites, The lower reaches of sewage treatment stations and tailings reservoirs are heavy metal enrichment areas. The Nemero index method shows that the soil environmental background value of Hubei Province and the national standard of soil environmental quality are taken as the evaluation criteria respectively. The evaluation results show that the soil samples from 40 sampling sites in a mining area in Hubei Province have reached the level of heavy pollution. The soil accumulation index method showed that the pollution index of CD was the highest, which contributed the most to the soil pollution in the mining area, whether the single heavy metal element at each site or the average value of all the heavy metal sites. The results of fuzzy comprehensive evaluation of soil in mining area show that the pollution of soil environment in mining area is serious and the problem of heavy metal pollution in soil should be solved urgently. The potential ecological risk assessment of heavy metal pollution in mining area shows that the potential risk of CD endangering the ecological safety of mining area is very large, and the ecological risk degree of the whole mining area is relatively strong. By synthesizing four evaluation methods, it can be seen that the mining area has been polluted mainly by heavy metals, and the regions where heavy metal pollution is more serious are the downstream of dressing and smelting area and the area of tailings reservoir.
【学位授予单位】：武汉工程大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;X751

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