| 题名 | 藏东南植被和土壤中典型持久性有机污染物的分布特征 |
| 作者 | 张淑娟 |
| 学位类别 | 硕士 |
| 答辩日期 | 2014-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 杨瑞强 |
| 关键词 | 多环芳烃（PAHs） 有机氯农药（OCPs） 得克隆类化合物 藏东南 植被 Polycyclic Aromatic Hydrocarbons (PAHs) Organochlorine Pesticides (OCPs) Dechlorane Plus (DPs) Southeast Tibetan Plateau Vegetation |
| 其他题名 | Distribution Patterns of Selected Persistent Organic Pollutants inVegetation and Soil from the Southeast Tibetan Plateau |
| 中文摘要 | 持久性有机污染物（POPs）是一类具有半挥发性、长期残留性、生物富集性和高毒性的化合物，能够随大气迁移到偏远的高山地区，并随着温度的降低沉降到地球表面，会对敏感的高山生态系统带来威胁。青藏高原的高山平均海拔超过4000米，远离人类活动干扰，但其周边是人类活动密集的区域如中国、印度和孟加拉等，这些区域尤其是印度次大陆国家产生的有机污染物会在印度季风的作用下对青藏高原产生影响。本文选取藏东南为研究区域，选取了三类具有代表性意义的POPs作为研究对象，包括有有机氯农药（Organochlorine Pesticides，OCPs），多环芳烃（Polycyclic Aromatic Hydrocarbons, PAHs）和得克隆类阻燃剂（Dechloranes Plus, DPs）。通过研究POPs在植被和土壤中的分布特征，探讨影响其空间分布特征的主要影响因素，深入理解高海拔区域POPs的迁移行为，并对污染物的可能来源进行评估。本论文共分为以下五章： 第一章对包括青藏高原在内的全球偏远高山区域POPs长距离迁移行为进行概述，并介绍了大气被动采样技术以及植被用于指示大气POPs污染的特性。 第二章介绍了样品的采集情况并建立了各样品中POPs的分析方法。本研究样品从五个梯度共48个采样点中分别采集了土壤、松针、树皮和苔藓四种介质。各介质目标化合物经加速溶剂萃取仪提取后，使用复合硅胶柱对提取液中的POPs进行净化和富集，然后分别使用气相色谱-电子捕获检测器完成OCPs、气相色谱-质谱完成PAHs和DPs的分离和分析，整个分析过程实行严格的质量控制。OCPs、PAHs和DPs在四种介质中的方法检出限分别在5.49-199 pg·g-1、15.9-2414 pg·g-1和20-30 pg·g-1之间，OCPs/DPs和PAHs的加标回收率分别在64.0-120%和76.2-99.6%之间。 第三章讨论了OCPs在植被和土壤中分布特征及来源解析。其中树皮和松针中OCPs的干重浓度显著高于苔藓和土壤中OCPs的干重浓度，而经脂质/总有机碳（TOC）校正后，苔藓中OCPs浓度显著高于其他介质中OCPs的浓度。由于各介质对大气POPs吸收具有特异性，因此它们作为大气POPs的指示物具有各自的适用性。本文结合多种介质共同指示大气POPs能够弥补单一介质指示污染的局限性，从而给出区域POPs污染的综合信息。我们还发现一些OCPs的干重浓度随海拔的升高具有显著上升的趋势。此外，OCPs在森林内土壤中的浓度显著高于其在林外土壤中的浓度，说明了森林能加强OCPs向土壤中的迁移，表现出POPs的森林过滤效应。另外，对OCPs单体比值的分析表明该区域有林丹和工业三氯杀螨醇输入。 第四章讨论了PAHs在植被和土壤中的分布特征及来源解析。发现PAHs在该区域的污染水平与北美山脉相当，但低于欧洲山脉。四种介质中PAHs干重浓度无显著性差异，但经过脂质/TOC归一化后，苔藓PAHs浓度显著高于其他介质。与OCPs不同的是，PAHs的浓度与海拔的关系并不显著，可能是因为当地PAHs的排放影响了污染物的分布模式。另一方面，与OCPs相似，PAHs受森林过滤效应影响明显，而且林内与林外浓度的比值（F/C）与PAHs单体的辛醇-大气分配系数的Log值（Log KOA）呈现显著的正相关关系，表明疏水性相对强的化合物的森林过滤效应强。另外，轻（2~3环）PAHs占总PAHs比例为78%-90%，说明该地区PAHs主要来源于长距离迁移，而且稳定单体比值分析表明PAHs多是由木材、煤和石油燃烧产生。 第五章讨论了DPs在苔藓中的分布特征。发现只有Dechlorane 602 （DEC 602）和得克隆（Dechlorane Plus，DP）在苔藓中能检出。其中DP浓度与全球其他偏远地区树皮中浓度相当，而DEC 602浓度比DP约高一倍,。另外，DEC602和DP与海拔并无显著相关关系，但DEC 602的浓度随着海拔的升高而增加，说明DEC 602随大气迁移能力更强。反式得克隆（anti-DP）所占比例与工业DP相似，说明苔藓对两种DP异构体的富集并无立体选择性。 最后对本研究工作进行总结并提出工作展望。 |
| 英文摘要 | Persistent Organic Pollutants (POPs) are characterized by their semi-volatility, persistence, bioaccumulation, and high toxicity. POPs can be transported to remote alpine regions by long-range atmospheric transport and deposited to the earth surface in cold high-altitude regions, posing threats to the sensitive alpine environment. With an average altitude of over 4000 meters, the Tibetan Plateau (TP) is isolated from human activities. Meanwhile, it is surrounded by the developing countries such as India and China with intense air pollution. Thus, the organic pollutants emitted by the surroundings can be transported to TP by the Indian monsoon and have an adverse impact on TP. We selected southeast TP as study area, and three kinds of POPs as the target compounds including organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs) and dechlorane plus (DPs). This study aimed to analyze the spatial distribution of OCPs, PAHs and DPs in vegetation and soils, and investigate possible factors influencing the spatial distribution. The possible sources of OCPs and PAHs were also analyzed. This thesis is comprised of the following five chapters: 1. This chapter reviewed the long-range atmospheric transport (LRAT) behavior in remote alpine regions including TP. The passive air sampler technique and vegetation used as bio-indicators for atmospheric pollution were also discussed. 2. The sampling procedure and analytical methods of POPs were elaborated in this chapter. Soil, conifer needle, tree bark and lichen samples were collected from 48 sites along the five transects. The target compounds were extracted by the accelerated solvent extraction (ASE). After that, the extracts were purified by the column chromatography, and determined by the gas chromatography-electron capture detector (GC-ECD) for OCPs, and gas chromatography-mass detector (GC-MS) for PAHs and DPs. The quality control was conducted during the whole procedure. The method detection limits for OCPs, PAHs, and DPs in the four matrices were in the range 5.49-199 pg·g-1, 15.9-2414 pg·g-1, and 20-30 pg·g-1, respectively. The recoveries of the spiked standards were 64.0 - 120% for OCPs/DPs, 76.2 - 99.6% for PAHs. 3. The distribution patterns and possible sources of OCPs in vegetation and soil were discussed in this chapter. The dry weight concentrations of OCPs in bark and lichens were much higher than that in lichen and soil samples. However, lichen showed much higher levels than those in other matrices when the concentration was normalized by lipid/total organic carbon (TOC). Because of the specific properties of each matrix in absorbing contaminants from the atmosphere, complementary analysis in multiple media can lead to a more comprehensive information of air pollution. A significantly positive correlation was observed between the concentration of several OCPs and the altitude, suggesting the mountain cold-trapping effect. Furthermore, soil from the forest sites showed higher concentrations of OCPs than that from the reference sites, which proved the forest filter effect in that the forest enhanced the transfer of OCPs from atmosphere to soil showing the forest filter effect. Besides, the isomer ratios of OCPs indicated input of lindane and dicofol in this region. 4. The distribution patterns and possible sources of PAHs were discussed in this chapter. The contamination level in the TP was comparable with that in North American mountains, and lower than that in European mountains. There was no significant difference among the dry weight concentrations of the four matrices. However, concentrations in lichen showed much higher levels than those in other matrices when normalized by lipid/TOC. No correlation ws observed between concentrations of PAHs and the altitude, which was different from the distribution of OCPs. Local emission sources might have an effect on the PAHs distribution pattern. Soil from the foreset sites also contained higher level than that from clearing sites, and the concentration ratio between the forest soil and the reference soil showed significantly positive correlation with logarithm transformed octanol-air distribution coefficient (Log KOA), indicating forest filter effect was pronounced for highly hydrophobic compounds. Besides, the light PAHs (2~3 ring) constituted 78%-90% of the total PAHs implying the PAHs in this region mainly came from long-range atmospheric transport, and the stable isomer ratio analysis indicated wood, coal and petroleum combustion was the main emission source of PAHs. 5. The distribution pattern of DPs in lichen was discussed in the chapter. Only DEC 602 and DP were detected in lichen samples. DP level in lichen samples was comparable with that in barks from other remote areas in the world, and the concentration of DEC 602 was twice of DP. Although no significant correlation was observed between DPs concentration and altitude, higher contamination level was observed in higher altitude regions indicating DEC 602 was prone to deposit in higher altitude regions. The ratio of anti-DP to total DP was in the range of technical DP indicating no stereoselective accumulation of the two isomers was observed in lichen samples. Finally, the highlight of the work was summarized and the future work was proposed. |
| 公开日期 | 2015-07-07 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/15606]  |
| 专题 | 生态环境研究中心_环境化学与生态毒理学国家重点实验室 |
| 推荐引用方式 GB/T 7714 | 张淑娟. 藏东南植被和土壤中典型持久性有机污染物的分布特征[D]. 北京. 中国科学院研究生院. 2014. |
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