兰州石化工业园区土壤—蔬菜系统重金属污染风险评价

发布时间：2018-12-11 04:43

【摘要】：重金属污染是一种常见的环境问题,而在兰州市西固石化工业区,由于历史遗留问题,部分土地被用作菜地,使得重金属污染状况更为复杂。本研究主要对石化工业区周边土壤-植物系统重金属污染状况进行了评价,并对兰州石化搬迁后的棕地修复进行了探讨。主要结论如下:1.兰州西固石化工业区周边菜地表层土壤中As,Cd,Cr,Cu,Hg,Pb含量均高于当地背景值,但低于中国土壤环境二级标准。石化工业区周边菜地甘蓝可食用部分的重金属含量均低于农产品安全质量无公害蔬菜安全要求。2.潜在生态风险评估的结果表明,当地土壤重金属污染对于生态的影响较为严重,其中Cd和Hg的累积为主要的风险来源。3.人体健康风险评估的结果表明,进入口腔的土壤颗粒与日常食用蔬菜为当地居民主要的重金属暴露途径。当地居民的健康风险主要来源于Cr和As的暴露。此外Pb也对当地居民带来一定的致癌风险。4.主成份分析和聚类分析将土壤中重金属来源分为三类:Cu,Cd,Cr和Pb主要是来源于工业活动和交通运输;Hg主要来自于煤的燃烧;As主要源于土壤母质。5.从石化工业区周边采集的植物提取土壤中重金属的能力均高于甘蓝,但低于超累积植物的标准。其中金叶榆,海棠,菊芋和榆叶梅提取重金属的能力较强。若将其做为当地土壤重金属污染的植物修复材料,需使用植物修复强化措施。6.根据研究结论,提出了如下建议:1)石化工业区的土壤不适于进行农业生产活动,应尽快改变土地用途并进行污染治理。2)为降低健康风险,当地居民应尽量在室外穿戴口罩以过滤空气中的颗粒物。同时尽量避免食用石化工业区菜地所生产的蔬菜。
[Abstract]:Heavy metal pollution is a common environmental problem, but in Xigu Petrochemical Industrial Zone of Lanzhou City, due to historical problems, some of the land is used as vegetable land, which makes heavy metal pollution more complicated. In this study, the pollution of heavy metals in the soil-plant system around the petrochemical industrial area was evaluated, and the remediation of brown land after the relocation of Lanzhou Petrochemical was discussed. The main conclusions are as follows: 1. The content of As,Cd,Cr,Cu,Hg,Pb in the surface soil of vegetable field around Xigu Petrochemical Industrial Zone of Lanzhou was higher than that of the local background value, but lower than that of the second class standard of soil environment in China. The contents of heavy metals in edible parts of vegetable fields around petrochemical industrial area are lower than the safety requirements of agricultural products, pollution-free vegetables. 2. The results of potential ecological risk assessment showed that the ecological effects of heavy metal pollution on soil were serious, and the accumulation of Cd and Hg was the main risk source. The results of human health risk assessment showed that soil particles entering the mouth and daily edible vegetables were the main exposure pathways of heavy metals to local residents. The health risks of local residents are mainly due to exposure to Cr and As. In addition, Pb also poses a carcinogenic risk to local residents. 4. 4. Principal component analysis and cluster analysis divided the heavy metal sources into three categories: Cu,Cd,Cr and Pb mainly derived from industrial activities and transportation; Hg mainly from coal combustion; As mainly from soil parent material. 5. The ability of extracting heavy metals from plants collected from the periphery of petrochemical industrial area was higher than that of cabbage, but lower than the standard of superaccumulative plants. Among them, Ulmus elm, Begonia chinensis, Jerusalem artichoke and Ulmus pumila had strong ability to extract heavy metals. If it is used as a phytoremediation material for heavy metal pollution in local soil, it is necessary to use phytoremediation measures. 6. Based on the conclusions of the study, the following suggestions are put forward: 1) soil in petrochemical industrial areas is not suitable for agricultural production activities, land use should be changed as soon as possible and pollution treatment should be carried out. 2) in order to reduce health risks, Local residents should try to wear masks outdoors to filter particulates in the air. At the same time, try to avoid eating vegetables produced by vegetable fields in petrochemical industrial areas.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X820.4

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