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题名: 二噁英分析方法与大气中的分布特征研究
作者: 周志广
学位类别: 博士
答辩日期: 2014-12
授予单位: 中国科学院研究生院
授予地点: 北京
导师: 赵斌
关键词: 二噁英,高分辨气相色谱-高分辨质谱,快速筛查法,大气,多级监测 体系,Dioxins, HRGC-HRMS, rapid screening method, atmosphere, multilevel monitoring solution
其他题名: Research on the Analytical Methods and Distribution Characteristics in Atmosphere for PCDD/Fs
学位专业: 环境科学
中文摘要:       二噁英类(PCDD/Fs)是典型的持久性有机污染物,并首批被列入《斯德哥尔摩公约》优先控制的持久性有机污染物名录。初步估算,我国二噁英类的年排放量高达10 kg TEQ,在目前公开报告二噁英类排放量的国家中居首位。这些都对二噁英类污染的监测及监管提出了更高的要求。二噁英检测技术主要分为仪器分析方法和生物检测方法。仪器分析方法可以准确定量每种异构体,因此被称为“黄金标准”;生物检测方法由于其较仪器分析方法更加简便、快速和经济,更加适用于对大量样品的筛查。而样品前处理无论对仪器分析方法还是生物检测方法而言,都是直接影响最终检测结果的关键步骤。每个标准分析方法都有相匹配的前处理方法,而应用简便快速的方法实现对干扰化合物的有效分离是前处理方法学中的难点。因此,本研究首先开展了针对二噁英分析的前处理方法的系统性研究,发展了新型样品净化方法,并采用实际环境样品进行了方法的适用性研究。由于大气污染状况日趋严重,对环境分析也提出了更多要求,因此本研究进一步应用二噁英分析方法,开展了对大气及垃圾焚烧废气中二噁英的形态分布规律的研究。具体研究结果如下:
      快速简便的前处理方法及其分离净化效果:针对二噁英的萃取方法,开展了对现有方法的比对研究,并在此基础上优化了关键步骤,针对飞灰样品建立了一套更加快速的萃取方法,方法的回收率较标准操作方法更优,并将操作时间由72 小时缩减为6 小时。针对二噁英的快速净化和分离方法,发展了2 种新方法,酞氰铜硅胶分离法和超级活性炭分离法。两种方法的二噁英回收率均可满足标准的要求,同时较标准方法更加简便且节省溶剂。但是酞氰铜硅胶分离法无法将non-ortho PCBs 与二噁英进行有效分离,而超级活性炭分离法则可以实现对non-ortho PCBs 的有效分离,提示两种方法具有不同的适用范围。
      前处理方法对二噁英分析的适用性及实用性的研究:研究发现上述方法可以用于下一步的二噁英分析,尤其适用于二噁英报告基因生物检测法。基于前一章方法学的研究,建立了完整的样品前处理流程,并采用飞灰和土壤样品验证了前处理方法的实用性。首先对固体废弃物焚烧产生的38 个飞灰样品进行了验证,生物检测分析方法与仪器分析方法的检测结果呈现出良好的相关性,相关系数为0.99。此外还对39 个垃圾焚烧厂周边土壤样品进行了检测,生物检测所得到的结果与仪器分析方法相比仍具有良好的相关性,相关系数为0.92,较飞灰样品略低,考虑为土壤基质的复杂性所致。说明所建立的前处理方法可应用于对飞灰、土壤等样品的二噁英筛查。
      大气中二噁英的形态分布规律研究:主要针对北京城区大气的二噁英形态分布进行了研究。分析结果表明,北京市大气中的二噁英异构体以PCDFs 为主,尤其2, 3, 4, 7, 8-PeCDF 所占比重较大,具有明显燃烧源的特征,北京大气中的二噁英浓度在冬季时要大于夏季,发生雾霾时的浓度要大于无雾霾时,在雾霾时浓度甚至超过0.6 pg-TEQ/m3,在主城区内并没有发现明显空间差异性,溴代二噁英的浓度要低于氯代二噁英,在形态分布上亦出现了与氯代二噁英相似的规律。同时,对大气样品进行了二噁英生物分析方法的检测,发现总毒性当量与仪器分析方法呈现出很好的相关性,相关系数为0.97。
      废气中二噁英的形态分布特征研究:论文选取危险废物焚烧及医疗垃圾焚烧产生的废气、烧结废气,以及生活垃圾焚烧产生的废气进行了分析。分析结果表明,每种废气中PCDFs 对总TEQ 的百分比要大于PCDDs,而且主要以2, 3, 4, 7,8-PeCDF 为主,这与大气中的二噁英分布呈现相似的规律。同时也对每种废气样品进行了生物检测,两种分析方法呈现出了良好的相关性,将样品综合起来考虑,亦呈现出良好的相关性,相关系数为0.98。
      此外,由于在环境管理实践中涉及不同层次的监控要求,需要有机结合仪器分析及生物检测法,建立多级监控的解决方案,将先进的环境分析技术应用于实际的环境管理工作。因此,本研究在对二噁英分析方法的展开研究的同时,提出了针对污染源检测、自然介质的日常监测以及应急监测等的二噁英多级监控方案,力争为二噁英的污染防治提供技术支持。
英文摘要:       Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are a group of persistent organic pollutants (POPs), which have been first added to the prior controlled organic pollutants list in Stockholm Convention. It is estimated that the annual emission of PCDD/Fs in China adds up to 10 kg TEQ, taking the lead among the countries that released national dioxin inventories worldwide. The analytical methods for dioxin consist of instrumental analysis and bio-analytical methods. The instrumental analysis is capable of precisely quantifying each congener, thus considered as “golden standard”. The bio-analytical methods are simpler, cheaper and quicker than that of instrumental analysis, and hence have been applied in rapid screening of dioxins in a batch of samples. Sample pretreatment is a vital procedure for both instrumental and bio-analytical analysis, dictating the accurate quantification. Therefore, to develop a simple, rapid and efficient separation
of interfering components is one of the most difficulties in pretreatment methodology. In this study, we have conducted extensive research on pretreatment methods for dioxin analysis, and developed new sample preparation systems which were applied to environmental samples for method verifications. As the air quality deteriorating, demands for environmental analysis are sustainably growing. In the thesis, we have studied the characteristics of dioxins in ambient air and flue gas samples using the developed purification and analytical techniques. The major findings are summarized as below:
      Development of pre-treatment methods and its efficacy:  In this study, two new methods were developed for sample clean-up and separation for dioxins, one was based on copper phthalocyanine bonded silica gel, and the other was based on super activated carbons. Both of them were verified to have high recovery rate for dioxins, which fulfilled the national criteria. These results implicated that the pre-treatment method is suitable for subsequent analytical methods for dioxins, in particular for the bio-analytical methods. However, separation method based on copper phthalocyanine bonded silica gel failed to separate non-ortho PCBs from dioxins, while the one based on super activated carbons could, indicating their difference in potential applications.
      Verifications of the methods: To test if the newly developed methods are applicable and practical for dioxin analyses in real environmental samples, fly ash samples and soil samples were employed. Thirty-eight fly ash samples collected from solid waste incinerations were employed in the first round of verification. The results of the bio-analytical method showed a good linear relationship compared with that of instrumental method (the correlation coefficient was 0.99). In the second round of verification, Thirty-nine soil samples collected around waste incineration plants were used. The results of the bio-analytical method showed a reasonable linear relationship compared with that of instrumental method (the correlation coefficient was 0.92). The complexity of soil matrix might be one of the reasons for the lower coefficient for soil sample analysis.
      Distribution of dioxin like compounds in the atmosphere of urban areas in Beijing: The results showed that PCDFs was the dominant homologue, in particular, 2, 3, 4, 7, 8-PeCDF was the most important contributor. This feature of the homologue profile was consistent with the characteristics of combustion sources. The concentrations of PCDD/Fs in Beijing atmosphere in the winter were significantly higher than those in the summer. The concentrations of PCDD/Fs in the air samples collected on the days with haze were significantly higher than those without haze. Moreover, PBDD/Fs could be detected in the samples with the same distribution pattern as that of PCDD/Fs.
      Distribution characteristics of PCDD/Fs in flue gas samples: The flue gas samples were obtained from four kinds of incinerators, classified into hazardous, medical and municipal-solid waste, and iron ore sintering. The results showed that the contribution of PCDFs to the total I-TEQ was higher than those of PCDDs. Similar with the distribution pattern of Beijing atmosphere samples aforementioned, 2, 3, 4, 7, 8-PeCDF, in particular, was the greatest contributor to total I-TEQ among other congeners. Apart from HRGC-HRMS, bio-analytical method was employed as well. A good correlation between the total TEQ data by using the two methods was obtained.
      At last, with the “golden standard” method and the latest developed rapid screening methods for dioxin analysis, a multilevel monitoring solution was proposed. Given different requirement of environmental management under different conditions, HRGC-HRMS needs to be coupled with the rapid screening methods, such as a reporter gene based bio-analytical method.

内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/34484
Appears in Collections:环境化学与生态毒理学国家重点实验室_学位论文

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Recommended Citation:
周志广. 二噁英分析方法与大气中的分布特征研究[D]. 北京. 中国科学院研究生院. 2014.
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