黄、东海沉积物中多氯联苯的分布及来源

发布时间：2018-04-27 02:12

  本文选题：多氯联苯 + 来源解析　； 参考：《中国海洋大学》2014年博士论文

【摘要】：自1970s发现其毒性以来，多氯联苯（PCBs）在环境中的含量以及其迁移转化一直是研究的热点。PCBs作为一种典型的持久性有机污染物，其来源与人类生产活动密切相关。在本研究中，我们选择受陆源输入影响较明显的黄、东海作为研究对象，通过分析该区域沉积物中PCBs的含量、组成及分布来揭示陆架海生态环境受陆源输入的有机污染物的影响情况。 本论文通过对该区域中66个表层沉积物样品和4根沉积柱中PCBs的含量及组成分析，结合统计学模型对PCBs的来源进行解析。主要在以下几方面取得了一些进展和新的认识： (1).将超声辅助碱液分解杂质与溶剂萃取相结合，建立了一种快速高效净化、萃取沉积物中多氯联苯（PCBs）的气相色谱分析方法。超声辅助条件下，，在2.0mol L-1的NaOH甲醇溶液中超声10min，利用NaOH甲醇溶液的碱解作用即可使有机氯农药（OCPs）完全分解，在利用有机溶剂萃取沉积物中PCBs的同时消除OCPs等的干扰。在优化的实验条件下，PCBs各单体的回收率在72.1%－113.7%，相对标准偏差在0.4%－6.3%(n=6)之间。气相色谱图显示，碱解净化后杂质含量显著减少，基线得以明显改善，能满足定性定量检测的要求。 (2).东海内陆架泥质区表层沉积物中PCBs含量为24.3~343.3pg/g，平均126.7pg/g，浓度高值出现在长江口附近区域。单体组成以3Cl-5Cl CBs为主，占76.1%；含氯量45.1%-58.8%，平均49.9%，单体组成特征与国产PCBs的单体组成较为相似；虽然PCBs浓度在河口区出现高值，但含氯量较低，随离长江口距离增加，含氯量有增加趋势。该区域表层沉积物中PCBs的分布呈现明显的来源控制特征，表明长江可能是该区域中PCBs的主要输入源。 (3).黄海中部区域表层沉积物中PCBs含量为99pg/g~3.13ng/g，平均715pg/g，浓度高值主要出现在36°N断面附近。5Cl CBs含量显著偏高，占43.70%；沉积物中PCBs的含氯量介于47.64%~58.15%,平均53.45%，与东海内陆架泥质区相比，该区域沉积物中PCBs的含氯量较高，高氯取代单体含量所占比重显著偏高。该区域表层沉积物中PCBs的分布受控于沉积环境，河流输送的PCBs可能对该区域中PCBs的含量贡献较少。 (4).对比了主成分分析-多元线性回归（PCA-MLR）与偏最小二乘回归（PLSR）的源解析结果。两种方法能够给出相近的成分载荷，主成分1（PC1）相似度较高，但其他成分样本得分相差较大，其结果表明PLSR所解析结果更加精细和便于识别。基于PLSR的解析结果，东海内陆架泥质区表层沉积物中的PCBs64.4%来源于地表径流输送入海的工业合成PCBs（3Cl CBs占主导），21.8%来源于大气沉降（5ClCBs占主导），13.8%来源于沿岸城市排污（高氯取代为主）；黄海表层沉积物中的PCBs60.5%来源于大气沉降输送的非故意产生的PCBs；24.0%来源于国产5Cl CBs，15.5%来源于经河流输送入海的3Cl CBs。 (5).近一个世纪以来，长江口区域PCBs的沉积记录受PCBs的生产使用影响明显，浓度峰值出现在1950s-1960s；在近代PCBs的含量有逐渐增高的趋势。近百年来东海内陆架泥质区所沉积的PCBs中大部分（＞70%）来源于工业合成的PCBs泄漏，人为活动中非故意产生的PCBs所占比例较少；据PLSR结果，在近几十年工业合成的PCBs对该区域中PCBs的影响程度有增加趋势，而非故意产生的PCBs影响程度并无明显的变化趋势，说明非故意过程中PCBs的形成受多种因素的影响，其产生量与工业生产总值并不是简单的线性关系。
[Abstract]:Since 1970s has been found to be toxic, the content of polychlorinated biphenyls (PCBs) in the environment and its migration and transformation have always been the focus of research,.PCBs as a typical persistent organic pollutant. Its source is closely related to human production activities. In this study, we choose the yellow and East China Sea as the research object, which is influenced by land source input. By analyzing the content, composition and distribution of PCBs in the sediments of this area, we can reveal the influence of the organic pollutants from the terrigenous source on the ecological environment of the shelf sea.
Based on the analysis of the content and composition of PCBs in 66 surface sediment samples and 4 sedimentary columns in this area, the source of PCBs is analyzed with statistical model. Some progress and new understanding are made in the following aspects:
(1) a rapid and efficient purification method for the extraction of polychlorinated biphenyls (PCBs) in sediments was established by combining the ultrasonic assisted lye decomposition impurities and solvent extraction. The ultrasonic 10min was used in the NaOH methanol solution of the 2.0mol L-1 under the ultrasonic assisted condition, and the organochlorine pesticide (OCPs) could be finished by the alkali solution of NaOH methanol solution. Full decomposition, in the use of organic solvent extraction of PCBs in the sediment at the same time elimination of OCPs interference. Under the optimized experimental conditions, the recovery of PCBs monomers is 72.1% - 113.7%, the relative standard deviation is between 0.4% and 6.3% (n=6). Gas chromatography shows that the content of impurities in the alkaline solution is significantly reduced, the baseline is obviously improved and can be satisfied. The requirements for the quantitative detection of sex.
(2) the content of PCBs in the surface sediments of the muddy area of the East China Sea is 24.3~343.3pg/g, with an average of 126.7pg/g and high concentration in the vicinity of the Yangtze Estuary. The composition of the monomer is mainly 3Cl-5Cl CBs, accounting for 76.1%, the chlorine content is 45.1%-58.8%, and the average composition is similar to that of the homemade PCBs, although the PCBs concentration is in the estuary area. There is a high value, but the chlorine content is low. With the increase of the distance from the Yangtze Estuary, the chlorine content increases. The distribution of PCBs in the surface sediments of this region shows a distinct source control feature, indicating that the Changjiang River may be the main source of PCBs in this area.
(3) the content of PCBs in the surface sediments of the central the Yellow Sea region is 99pg/g~3.13ng/g, with an average of 715pg/g, and the high concentration of the concentration is mainly higher in the vicinity of the 36 degree N section, and the content of.5Cl CBs is 43.70%. The chlorine content of PCBs in the sediments is between the 47.64%~58.15% and the average of 53.45%. The content of PCBs in the sediments of the East China Sea is compared with the mud content in the East China Sea. The proportion of PCBs in the surface sediments of this region is controlled by the sedimentary environment, and the PCBs transported by the river may contribute less to the content of PCBs in this area.
(4) compared the source analysis results of principal component analysis multivariate linear regression (PCA-MLR) and partial least squares regression (PLSR). The two methods can give similar component loads, the similarity of principal component 1 (PC1) is higher, but the scores of other components are different, and the results show that the PLSR results are more precise and easier to recognize. PLSR based on the results. The analytical results show that PCBs64.4% from the surface sediments of the muddy area of the East China Sea inland shelf is derived from the industrial synthetic PCBs (dominated by 3Cl CBs) transported to the sea by surface runoff. 21.8% originates from atmospheric sedimentation (5ClCBs dominated) and 13.8% from coastal city discharge (high chlorine substitution), and the PCBs60.5% in the surface sediments of the Yellow Sea is derived from atmospheric sedimentation. The unintentional PCBs; 24% came from the domestic 5Cl CBs, and 15.5% came from the 3Cl CBs. transported to the sea through the river.
(5) (5) the deposition records of the Yangtze Estuary region have been affected by the production and use of the PCBs in the last century. The peak concentration appears at 1950s-1960s, and the content of PCBs in modern times is increasing gradually. Most of the (> 70%) of the PCBs deposited in the mud area of the inland shelf of the East China Sea in the last hundred years is derived from the industrial synthesis of PCBs leakage and human activities. The proportion of unintentionally produced PCBs is less; according to the results of PLSR, the impact degree of industrial synthetic PCBs on PCBs in this area has increased in recent decades, and the degree of unintentionally produced PCBs has no obvious change trend. It shows that the formation of PCBs in unintentional process is influenced by many factors, and its production amount and industrial production are general. Value is not a simple linear relationship.

【学位授予单位】：中国海洋大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：X55

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