莱州湾区域河流沉积物和大气中六溴环十二烷的污染特征初步研究

	莱州湾区域河流沉积物和大气中六溴环十二烷的污染特征初步研究
	刘艺凯
学位类型	硕士
导师	唐建辉 ; 于志强
	2013-05-24
学位授予单位	中国科学院研究生院
学位授予地点	北京
学位专业	海洋化学
关键词	六溴环十二烷溴系阻燃剂莱州湾沉积物大气污染特征异构体组成手性特征
其他摘要	六溴环十二烷（HBCDs）是继多溴联苯醚（PBDEs）和四溴双酚 A（TBBPA）之后的世界第三大溴系阻燃剂。由于其良好的阻燃性能和较低的成本，而被广泛地应用于建筑材料、装潢纺织品、电子电器等领域。HBCDs 作为添加型的阻燃剂，与材料之间没有化学键的束缚，因此容易在产品的生产、加工、运输、使用和处理的过程中释放到环境中去；特别是作为五溴和八溴联苯醚的替代品，其使用量逐年增加，造成一定程度的污染。近年来研究发现，HBCDs 具有长距离迁移性、持久性、生物富集性和生物毒性等典型持久性有机污染物（POPs）的特性，引起国际社会的关注，但是我国关于 HBCDs 的研究工作刚刚起步，仅有少量的文献报道，且主要集中在南方地区，如广州电子垃圾拆解地和珠江三角洲等地区。本论文以我国溴系阻燃剂生产厂家集中地之一的渤海莱州湾邻近区域作为研究对象，采用液相色谱/三重四极杆质谱（LC-MS/MS）检测环境样品中 HBCDs异构体及手性对映体，调查了 HBCDs 在研究区域河流沉积物和大气样品中的含量水平、来源、分布状况、影响因素、异构体组成及手性特征等，为进一步研究其分布、源特征和迁移转化机制提供数据支持，并为我国建立 HBCDs 环境健康评估提供基础性和原始性资料。本论文取得的研究结果如下： 1）莱州湾河流沉积物中HBCDs 的含量范围为 0.03~20.17 ng·g-1，平均值为2.14 ng·g-1；HBCDs 的含量水平与亚洲地区相当，与欧洲一些国家相比处于较低的水平。HBCDs 的分布呈现明显的点源特征：工业区>城市区>未分类区>农业区，说明当地的化工厂、溴阻燃剂厂等生产、加工活动是一个重要的 HBCDs 释放源。通过对 HBCDs 和 PBDEs 相关性分析得出，HBCDs 和 PBDEs 具有相似的输入途径。除了工业源影响 HBCDs 的分布特征外，该区域沉积物中总有机碳（TOC）也是其分布的一个影响因素，特别是非工业区河流沉积物中 HBCDs 和TOC 具有良好的相关性（r=0.63, p=0.011）。但是可能受到复杂环境的影响，其分布与粒度的相关性差。2）莱州湾河流沉积物中 HBCDs 异构体组成各不相同，α-HBCD、β-HBCD和 γ-HBCD 的平均相对丰度分别为 21.5%、8.2%和 71.6%，其异构体组成与技术产品不同，HBCDs 可能在沉积物介质中发生了生物转化或者在其生产和释放到环境的过程中发生了光/热等非生物转化。不同功能分区内 HBCDs 的组成变化有明显的不同，可能是由于不同功能分区的 HBCDs 来源不同或者发生了不同的环境行为，工业区 HBCD 异构体组成更接近于技术产品。沉积物样品中 α-HBCD、β-HBCD 和 γ-HBCD 的手性特征值（EFs）的范围分别为 0.371~0.489、0.444~0.537和 0.458~0.538，与国内技术产品存在显著性差异。手性特征作为示踪生物/微生物转化的依据，暗示了研究区域沉积物中可能发生了 HBCDs 对映体生物转化现象。 3）莱州湾工业区大气中HBCDs 的含量范围（气相+颗粒相）是 140.2~2149.8pg·m-3，平均值为 685.2 pg·m-3，且HBCDs 几乎全部（93.3%~99.9%）分配在颗粒相中。研究区域 HBCDs 的含量水平远高于国内外其他地区，与欧洲工厂区大气中 HBCDs 的污染水平相当，需要及早引起相关部门的重视。 4）莱州湾工业区大气中 HBCDs 异构体组成各不相同，α-HBCD、β-HBCD和 γ-HBCD 平均相对丰度分别为 23.4%、24.8%和 51.8%，与技术产品具有明显的差别，且研究发现大气样品中 α-HBCD 与 γ-HBCD，以及 β-HBCD 与 γ-HBCD的百分比含量间存在着显著的负相关，3 种异构体可能在其生产和释放过程中发生了热/光转化。大气颗粒物样品中 α-HBCD、β-HBCD 和 γ-HBCD 的 EFs 值范围分别为 0.476~0.526、0.435~0.466 和 0.448~0.502，α-HBCD 与技术品中的 EFs 值并没有显著的差异，而 β-HBCD 和 γ-HBCD 却与技术产品的 EFs 值有显著性地差别，但是由于数据量有限，有待进一步研究其转化机制。综上所述，通过优化 HBCDs 异构体和对映体的分析方法，有助于开展环境和人体中 BFRs 的研究。根据上述研究结果，初步了解了莱州湾河流沉积物及大气中 HBCDs 的污染现状，基于对 HBCDs 异构体组成和手性特征的研究，初步探讨了区域 HBCDs 的污染特征、引起 HBCDs 异构体组成发生改变的可能影响因素以及 HBCDs 的环境过程，包括迁移、转化行为等，从而为控制污染物提供基础性依据。 ; Hexabromocyclododecanes (HBCDs) are the third most produced brominated flame retardants (BFRs). They are mainly applied in building materials for thermal insulation, in upholstery textiles, and to a minor extent in electrical household equipments. As additive BFRs, they are not chemically bonded into the polymer matrix, and can easily release and leach from HBCD-containing consumer products during processing, transportation, using and treatment. Since HBCDs have been replacements for penta- and octa-BDEs, they became ubiquitous contaminants in the environment. Recent studies indicated that HBCDs share the major characteristics of persistent organic pollutions (POPs): long-range transport, persistent, bioaccumulation and toxicity, which raised great concerns in the international environmental community. However, based on the best of our knowledge, little is known about HBCDs in the Chinese environment, and most of these studies mainly concentrated in the southern region, such as e-waste recycling areas and the Pearl River Delta region. In this thesis, we collected riverine surface sediments and atmospheric samples in Laizhou Bay area, which is a center of bromine-related producers in China and the biggest BFRs manufacturing in Asia. A liquid chromatography coupled to triple quadrupole mass spectrometer (LC-MS/MS) method was used for the determination of HBCD diastereoisomers and enantiomers, which can be used to investigate the pollution status, distributions, possible sources, diastereoisomers profiles and enantiomer fractions of HBCDs. From this thesis, several conclusions are drawn as follows: 1) The concentrations of total HBCDs in the surface sediments ranged from 0.03 to 20.17 ng·g-1，with a mean value of 2.14 ng·g-1. HBCDs level was omparable to regions in Asia, but lower than reported data in Europe. The distributions of HBCDs present the obvious characteristics of point sources in the study areas: industrial > urban > unclassified > rural, indicating that a strong influence of direct emission from local factories. Due to good correlation between the concentrations of HBCDs and PBDEs, they may have the similar input way. In addition to industrial sources, nice correlation between total organic carbon (TOC) and HBCD concentrations suggest that TOC is also an influencing factor for HBCDs distribution. However, HBCDs concentrations and grain sizes in sediments showed a poor correlation. 2) HBCD diastereoisomers profiles are different from commercial products, with the average relative abundance of 21.5%, 8.2% and 71.6% for α-HBCD, β-HBCD and γ-HBCD, respectively. This might due to biological process or thermal or photolytic shift during the production process and in the environmental media. Moreover, HBCD diastereoisomers profiles were significantly different in diverse functional zones, suggesting that diverse sampling sites may have various HBCD sources. The enantiomeric fraction values for α-HBCD, β-HBCD and γ-HBCD ranged from 0.371 to 0.489, from 0.444 to 0.537 and from 0.458 to 0.538, respectively, and differed from domestic commercial products. The differences suggested that stereoselective transformation of the three diastereoisomers occurred, which is more likely due to biological conversion process in the sediment matrix. 3) The concentrations of total HBCDs in atmospheric samples (gas + particle phases) ranged from 140.2 to 2149.8 pg·m-3, with a mean value of 685.2 pg·m-3 , and HBCDs were predominantly sorbed to the atmospheric particulate (93.3%~99.9%). HBCDs levels were similar to some industrial districts of Europe, yet much higher than reported data from domestic and oversea unban and rural atmosphere. This should arouse much attention. 4) The average relative abundance of α-HBCD, β-HBCD and γ-HBCD in airborne samples is 23.4%, 24.8% and 51.8%, differed from the commercial products. Moreover, the percentage content between α-HBCD and γ-HBCD, β-HBCD and γ-HBCD has significantly negative correlation, suggesting that thermal conversation during the productive process or photolytically-mediated shift in the environmental media existed. The enantiomeric fraction values for α-HBCD, β-HBCD and γ-HBCD in atmospheric particulate ranged from 0.476 to 0.526, from 0.435 to 0.466 and from 0.448 to 0.502, respectively. The chiral signatures of α-HBCD showed no significant difference from commercial mixture, while β-HBCD and γ-HBCD revealed the opposite characteristics, implied that enantiomeric or diastereoisomeric transformation happened in atmospheric medium，may also involved the bioprocesses.However, due to the limited data in our study, the conversion mechanism remains to be further research.Based on the optimized method for ananlyzing HBCD diastereoisomers and enantiomers, we can further apply it in the BFRs ananlysis of the environmental and human samples. According to the above results, we preliminarily understand the pollution status, pollutant characteristics, and environmental processes of HBCDs in the riverine sediments and atmosphere from Laizhou Bay area. Thus, they can provide the fundamental basis on the control of pollutants.
文献类型	学位论文
条目标识符	http://ir.yic.ac.cn/handle/133337/6355
专题	中国科学院烟台海岸带研究所知识产出_学位论文
推荐引用方式 GB/T 7714	刘艺凯. 莱州湾区域河流沉积物和大气中六溴环十二烷的污染特征初步研究[D]. 北京. 中国科学院研究生院,2013.

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