西安市灞桥燃煤电厂周边土壤和灰尘介质中重金属污染特征研究

发布时间：2018-07-16 19:05

【摘要】：本人通过选取西安市灞桥燃煤电厂周边100m圈层、400m圈层、1000m圈层和1500m圈层的土壤和灰尘两种环境介质作为研究对象,采集了80个土壤和80个灰尘样品,分别测定了两种介质中As、Ba、Cd、Co、Cr、Cu、Mn、Ni、Pb、V和Zn等11种重金属元素的含量、赋存形态,并进行了空间分布特征、来源以及污染现状评价和风险评价等方面的研究。主要得到以下的结论：1.元素的统计分析结果看：电厂周围土壤介质中As、Ba、Cd、Co、Cr、Cu、 Mn、Ni、Pb、V口Zn等11种重金属元素的平均值分别为28.6、999.9、0.467、59.1、99.1、56.5、944.3、51.6、141.4、126.0、186.4 mg.kg~(-1),特别是元素Cd、Co和Pb,分别是陕西土壤背景值的5.0,5.6和6.6倍,在土壤中明显富集；西安灞桥燃煤电厂周围灰尘中As、Ba、Cd、C0、Cr、Cu、Mn、Ni、Pb、V和Zn等11种重金属元素的平均值为84.2、1434.5、1.4、56.8、314.6、69.3、666.7、37.2、223.9、106.5、278.83 mg.kg~(-1),特别是元素As、Cd、Co、Cr和Pb,分别是陕西土壤背景值的7.6、14.8、 5.4、5.0、10.5倍,在灰尘中明显富集。2.形态分析结果表明：在电厂周围土壤中,重金属元素随环境条件发生迁移转化的顺序Mn(72.6%)Co(69.2%)Zn(58.5％)≈Pb(58.3％)Cu(41.3%)Ba(32.2%) ≈Ni(31.9%)V(24.0%)Cr(20.6%)；在灰尘中重金属元素随环境发生迁移转化的顺序为:Co(85.1％)Pb(64.6%)Zn(59.7%)Cu(54.7%)Mn(41.1％)Ni(35.1％) Cr(22.3％)Ba(21.8%)V(21.2%).可见,元素Co、Cu、Pb、Zn在土壤和灰尘介质中均易发生二次污染,潜在危害较大,需要优先进行防控。3.在不同的圈层,电厂周边土壤和灰尘中的重金属浓度和赋存形态都存在一定的差异；在不同圈层,元素Mn、Co、Cu口Pb都易发生迁移转化,对环境潜在危害较大。4.西安市灞桥燃煤电厂周边土壤重金属来源可分为三类：As、Cd、Cu、Pb主要来源于交通污染源、煤炭燃烧和工业排放；Cr、Mn、Ni、V、主要来源于成土母质；Ba和Zn受工业排放、交通污染和居民活动的综合作用的影响,Co主要受自然与人为因素共同控制,其中Co的人为来源主要是煤炭燃烧和其它工业源排放。西安市灞桥燃煤电厂周边灰尘重金属来源可分为三类：As、Cd、Cr、Cu、Pb、V和Zn主要来源于交通污染源、煤炭燃烧和工业排放；Mn主要来源于成土母质；Ba、Co、Cr和Ni主要受自然与人为因素共同控制。5.运用地累积污染指数法、内梅罗综合污染指数法、污染负荷指数法和潜在生态风险指数法对西安灞桥燃煤电厂周边土壤和灰尘介质中的重金属元素进行了污染现状评价和风险评价。结果表明：燃煤电厂周围灰尘中重金属的污染程度比土壤中重金属污染程度严重,且土壤中重金属Cd、Co、Pb口Zn污染较重,灰尘中重金属As、Cd、Co、Cr、Cu、Pb和Zn污染严重。
[Abstract]:By selecting two kinds of soil and dust in the surrounding 100m circle, 400m circle, 1000m circle and 1500m circle, 80 soil and 80 dust samples were collected, and the contents of 11 kinds of heavy metal elements, such as As, Ba, Cd, Co, Cr, Cu, Mn, Ni, Ni, Cu, etc., were measured in the two media. The characteristics of spatial distribution, source, pollution status evaluation and risk assessment are studied. The following conclusions are obtained: the statistical analysis results of the 1. elements: the average value of the 11 heavy metal elements, such as As, Ba, Cd, Co, Cr, Cu, Mn, Ni, Pb, V mouth Zn, around the soil medium in the power plant 5944.3,51.6141.4126.0186.4 mg.kg~ (-1), especially the elements Cd, Co and Pb, are 5.0,5.6 and 6.6 times the soil background value of Shaanxi, and they are obviously enriched in the soil. The average value of the 11 kinds of heavy metals such as As, Ba, Cd, C0 in the dust of the coal-fired power plant in Baqiao, Xi'an 23.9106.5278.83 mg.kg~ (-1), especially elements As, Cd, Co, Cr and Pb, are 7.6,14.8 and 5.4,5.0,10.5 times of the soil background values in Shaanxi, respectively, and the obvious enrichment of.2. morphology in dust shows that the sequence of heavy metals in the soil around the power plants (72.6%) (69.2%) Cu (41.3%) Ba (32.2%) Ni (31.9%) V (24%) Cr (20.6%); the order of migration and transformation of heavy metals in the dust is Co (85.1%) Pb (64.6%) Zn (59.7%) Cu (54.7%) Mn (41.1%) Ni (35.1%) Cr (22.3%)). There are certain differences in the concentration and occurrence of heavy metals in the soil and dust surrounding the power plant, and there are certain differences in the concentration and occurrence form of the heavy metals in the soil and dust around the power plant. In different circles, the elements Mn, Co, and Cu port Pb are easy to migrate and transform, and the potential harm to the environment is larger.4., the source of heavy metals in the surrounding soil of Xi'an Baqiao coal fired power plant in Xi'an city can be divided into three categories As, Cd, Cu, Pb are mainly derived from traffic pollution sources, coal combustion and industrial emissions; Cr, Mn, Ni, V are mainly derived from the soil matrix; Ba and Zn are influenced by industrial emissions, traffic pollution and the integrated effects of residential activities, Co mainly controlled by natural and man-made factors, among which the main sources of Co are coal combustion and other industrial sources. As, Cd, Cr, Cu, Pb, V and Zn are mainly derived from traffic pollution sources, coal combustion and industrial emissions; Mn is mainly derived from soil parent materials; Ba, Co, Cr and Ni are mainly controlled by natural and man-made factors in the cumulative pollution index method, Nemero synthesis, Nemero synthesis Pollution index method, pollution load index method and potential ecological risk index method were used to evaluate the pollution status and risk assessment of heavy metals in the soil and dust medium surrounding Baqiao coal-fired power plants in Xi'an. The results showed that the pollution degree of heavy metals in the dust around the coal-fired power plant was more serious than the heavy metal pollution in the soil, and the soil was more serious than the soil. The heavy metals Cd, Co and Pb Zn in the soil are heavily polluted. Heavy metals such as As, Cd, Co, Cr, Cu, Pb and Zn in the dust are seriously polluted.
【学位授予单位】：陕西师范大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X773;X50

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