西安市城区干湿沉降中持久性有机物特征及其相关性研究

发布时间：2018-01-17 17:14

本文关键词：西安市城区干湿沉降中持久性有机物特征及其相关性研究　出处：《西安建筑科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：干、湿沉降是空气中持久性有机物去除的主要途径,也是地表环境中持久性有机物的主要来源。通过这一过程,完成了持久性有机污染物由大气向地表或水体的传输,是决定持久性有机污染物环境命运和人体暴露的重要因素。所以研究大气干、湿沉降中持久性有机物对保护环境和减少环境污染有着重要的意义。为了确定大气干湿沉降中持久性有机污染物的主要特征及干、湿沉降对大气中污染物去除的相对贡献,本研究选择西安市城区为研究对象,在东、西、南、北各区域的一环路和二环路共设11个采样点,采集了302个大气干、湿沉降样品。降雨样品经过液液萃取,降尘样品经过超声萃取,采用气相色谱法测定了36种持久性污染物的含量,它们分别为8种有机氯农药,12种多氯联苯和16种多环芳烃。通过计算沉降通量,得到不同采样点污染物的分布;并将采样点分为五个不同功能区,分析了不同功能区和不同环境介质中污染物的特征;此外,利用相关性分析污染物含量和TOC、累计晴天数之间的相关性,并对西安市城区大气干湿沉降中POPs进行了生态风险评价。结果表明:所测污染物中,16种多环芳烃和8种有机氯农药检出率均为100%,12种多氯联苯中,PCB157未检出,PCB123和PCB118检出率分别为97.4%和92.5%,其他9种检出率均为100%;就不同功能区而言,工业区交通要道区校园商业区居民区,交通要道和工业区污染物含量较多;就POPs的空间分布而言,南郊北郊东郊西郊,可以得到大气中POPs主要由燃油污染贡献;就POPs的存在特征而言,降雨降尘径流,得到湿沉降是大气环境中POPs的主要排除方式;将大气干湿沉降的两个影响因素晴天累积天数和TOC经过SPSS软件进行相关性分析,得到r0.7,P0.01,即它们都是大气中POPs干湿沉降的主要影响因素;采用效应区间法,对所测污染物进行生态风险评价,得到西安市大气沉降中POPs污染严重,污染最严重的是多氯联苯其次是有机氯农药污染和多环芳烃。
[Abstract]:Dry and wet deposition is the main way to remove persistent organic matter in air and the main source of persistent organic matter in surface environment. The transport of persistent organic pollutants from the atmosphere to the surface or water is an important factor that determines the fate of the environment and human body exposure. Persistent organic matter (pops) in wet deposition plays an important role in protecting environment and reducing environmental pollution. In order to determine the main characteristics and dryness of persistent organic pollutants in dry and wet deposition of atmosphere. The relative contribution of wet deposition to the removal of pollutants in the atmosphere, this study selected Xi'an urban area as the research object, and set up 11 sampling points in the first ring road and the second ring road in the east, west, south and north. 302 samples of dry and wet deposition were collected. The contents of 36 kinds of persistent pollutants were determined by gas chromatography after precipitation samples were extracted by liquid-liquid extraction, dust samples were extracted by ultrasonic extraction. They are 8 organochlorine pesticides, 12 kinds of polychlorinated biphenyls and 16 kinds of polycyclic aromatic hydrocarbons (PAHs). The sampling points were divided into five different functional areas, and the characteristics of pollutants in different functional areas and environmental media were analyzed. In addition, the correlation between pollutant content and TOCand the total number of sunny days was analyzed by correlation analysis. Ecological risk assessment of POPs in dry and wet deposition of air in Xi'an city was carried out. The results showed that the detection rate of 16 kinds of PAHs and 8 kinds of organochlorine pesticides were 100%. The positive rates of PCB123 and PCB118 were 97.4% and 92.5 in 12 PCB157, respectively, while the other 9 were 100. In terms of different functional areas, the content of pollutants in the main traffic roads and industrial areas of the industrial area is more than that of the residential area of the campus commercial district. As far as the spatial distribution of POPs is concerned, the POPs in the air is mainly contributed by fuel pollution in the eastern and western suburbs of the northern and southern suburbs. In terms of the existence characteristics of POPs, precipitation and dust-fall runoff and wet deposition are the main ways of eliminating POPs in atmospheric environment. Through the correlation analysis of the two influencing factors of dry and wet deposition, the accumulated days of clear days and TOC through SPSS software, we got the result of r0.7g / P0.01. That is, they are the main influencing factors of dry and wet deposition of POPs in the atmosphere. By using the effect interval method, the ecological risk assessment of the pollutants was carried out. The results showed that the pollution of POPs in Xi'an atmospheric deposition was serious, and the most serious pollution was PCBs, followed by organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs).
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X51;X131.1

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