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题名: 利用有机地球化学指标研究 几种入海有机污染物的环境行为
作者: 赵宗山
学位类别: 博士后
答辩日期: 2016-12
授予单位: 中国科学院研究生院
授予地点: 北京
导师: 蔡亚岐
关键词: 有机地球化学指标 ; organic geochemical index ; 有机污染物 ; POPs ; 来源 ; sources ; 归宿 ; fate ; 生物标志物 ; biomarker
其他题名: The Study on Environmental Behaviors of Several Marine Organic Pollutants Using Organic Geochemistry Index
学位专业: 生态学
中文摘要:       陆架海是连接陆地与海洋的纽带,也是受人类活动影响最明显的区域。近几十年来,大量污染物通过大气沉降、河流输运等方式进入海洋,并引发了一系列海洋环境问题及污染事件,严重威胁海洋生态系统。目前,海洋环境中污染物的来源解析的主要方法是扩散模型和受体模型,扩散模型的基础是污染源的排放特征,受体模型的基础是大量实际的环境样品(受体),二者具有一定的互补性。但二者的实质都是通过计算对污染物进行溯源和迁移转化分析,存在一定的局限性。
      分子生物标志物是海洋沉积有机质来源研究中重要的有机地球化学指标,可以反映沉积有机质中陆源-海源有机质的贡献。当前使用的海洋有机地球化学指标主要包括甾醇类、烯酮类和脂肪酸等生物标志物,它们具有在地质环境中不易降解、能够稳定存在和反映其生物来源及迁移转化的特点。本文利用海洋有机化学指标,对黄海及东海海域典型持久性有机污染物  (SCCPs、PCBs、OCPs等)的来源分布、迁移转化机制等进行了初步探讨。
       首先,基于总有机碳和生物有机分子等生物标志物参数,对长江口-闽浙沿岸海区SCCPs的来源进行了识别研究。SCCPs在研究区域各采样点均有检出,浓度平均值为24.0 ng/g d.w.,低于一般水平。沉积物中SCCPs含量从沿岸向深海逐渐降低,其高值区在东海沿海岸线呈带状分布。SCCPs含量与TOC及颗粒物粒度含量对比显示,它们之间呈现出较好的线性相关性,表明TOC及颗粒物粒度是影响有机污染物沉积分布的主要因素。ΣC27+C29+C31正构烷烃及陆源有机物(TOM)与SCCPs也表现出相似的分布特征及良好相关性,从侧面显示SCCPs与陆源有机物具有相同的来源和迁移路径,即都是主要通过长江输送入海并沿着浙江福建沿岸向南迁移。
      其次,利用分子生物标志物参数识别了东海不同海域PCBs的来源、转运和归宿行为。PCBs在东海海域广泛存在,在43个采样点中均有检出,平均含量为25.41 pg/g d.w。其中,低氯代PCBs同系物是PCBs这类污染物的主要组成部分。PCBs的空间分布呈现随离岸距离的增加污染物浓度逐渐降低的趋势,高值点主要分布于浙江-福建沿岸泥质区。TOC与PCBs的分布趋势基本一致,显示颗粒有机碳的吸附对PCBs空间分布的决定性作用。生物标志物ΣC27 + C29 + C31正构烷烃和BIT指标与PCBs对比显示,长江口及内陆架海域29°N以北的沉积PCBs主要来源于长江输入和大气沉降;济州岛西南方向大陆架中心海域的沉积PCBs主要来源于大气输运及沉降,并受到生物泵的影响;内陆架海域29°N以南的沉积PCBs主要来源于台州-温州地区产生的气态PCBs的沉降,以及长江输送。PCBs同系物组成与梯烷核心脂和近年东海水体缺氧调查数据也显示,PCBs在厌氧氨氧化活动比较明显的区域或者水体缺氧区域,更容易发生还原性脱氯作用。
       最后,还利用生物标志物探讨了海洋环境中携带OCPs进入沉积环境中的主要载体-海洋初级生产力。由于陆架海区域OCPs的入海路径主要包括大气沉降和河流输运,且入海后溶解态OCPs是其主要赋存形态,作为海洋生态系统基础的海洋浮游植物无疑是其重要的载体。研究结果显示,OCPs总量分布趋势由近岸向南黄海中部逐渐增加的趋势,最高点出现在南黄海中北部。粒度分析结果显示,OCPs的空间分布主要受控于粒度。结合浮游植物在海洋真光层中的广泛分布,以及颗粒有机质对OCPs的吸附,我们利用基于生物标志物识别陆海有机质的TMBR指标,估算了海洋浮游植物对南黄海OCPs沉积通量的贡献(>75%),指出了海洋初级生产力在南黄海OCPs沉降过程中的关键性作用。
英文摘要:       Shelf seas heavily affected by human activities are the link between the land and the ocean. Over the past few decades, large amounts of contaminants have been transferred into the ocean through atmospheric deposition and riverine input, led to series of marine environmental problems and caused serious threat to marine ecosystems. To date, the main source analysis methods for pollutants are diffusion model and receptor models. The basis of the diffusion model is the emission characteristics of pollution sources, while it is massive environmental samples (receptors) for receptor model. There is a certain complementarity between these two models. But in essence, both of them are based on the calculations of characteristic data for identifying the source, transferring and transforming of contaminants.
Molecular biomarkers are one of the most important marine organic geo-chemical indexes for identifying the source of sedimental organic matters in marine environment. The commonly used biomarkers are sterols, ketenes and fatty acids, which are resistent to degradation in geological environment and can reflect their biological source. In this paper, marine molecular biomarkers are used for studying the spatial distribution, source, transferring and transforming of POPs (such as SCCPs, PCBs and OCPs) in the Southern Yellow Sea (SYS) and the East China Sea (ECS).
      Firstly, the sources of SCCPs in the part of the ECS (Yangtze River Estuary and Zhejiang-Fujian coastal area) have been identified by using total organic carbon (TOC) and molecular biomarkers. SCCPs have been detected in all the sampling sites and the mean content of these sedimental SCCPs is 24.0 ng/g. SCCPs present an decreasing trend toward the sea and high values locate in the zonal area along the coastline. Compared with TOC and grain size analysis, there is a closely relationship between them, indicating that the distribution of SCCPs in the ECS are mainly affected by TOC and grain size. Additionally, by comparing with biomarkers of ΣC27+C29+C31 n-alkanes and the calculated terrestrial TOC (defined as terrestrial matter, TOM) with SCCPs, it has been found that there are broadly similar distribution patterns and good correlationships. The results indicated that TOM and SCCPs posses similar source and transferring paths; that is, both of them are mainly from the riverine input by Yangtze River and move towards the south along the coastline by the Zhejiang-Fujian coastal currents.
       Secondly, the source, transferring and environmental fate of PCBs in the ECS have also been studied by using these molecular biomarkers. PCBs have been detected in all the 43 samples and their mean content is 125.41 pg/g d.w. Among, low-chlorinated PCBs are dominated in all the PCB components. High values locate in the mud area of Zhejiang-Fujian coastal area. The similar patterns between TOC and PCBs suggest that the distribution of PCBs is mainly controlled by particle organic carbon. By comparing ΣC27+C29+C31 n-alkanes and BIT with PCBs, it can be concluded that: PCBs in the Yangtze River Estuary and the inner shelf north of 29 oN are mainly from the riverine input of Yangtze River, PCBs in the mud area southwest of the Cheju Island come from atmospheric deposition and PCBs in the inner shelf south of 29 oN are from the riverine input of Yangtze River and local coastal sources. The records of ladderane core lipids and hypoxia area in the past decade indicated that dechlorination degree of PCBs in the Yangtze River Delta and its adjacent areas with low dissolved oxygen is much higher than that in other regions.
       Finally, the role of marine productivity for the sinking of OCPs in the SYS have been also studied by using molecular biomarkers. Based on the fact that the main entering paths for OCPs into the shelf seas are atmospheric deposition and riverine input, and dissolved OCPs are the main forms for those OCPs existing in the water columns, it is undoubtedly that marine productivity should be the important carrier for the sinking of OCPs into marine sediments. The results of sedimentary OCPs presents that they presents an increasing trend towards the central basin of the SYS and the highest values locate in the middle-north region of the SYS. The spatial distribution is mainly controlled by grain size. Due to the fact that marine productivity live in the euphotic zone of water column and particle organic matter is preferring to adsorb OCPs, we assumed that there is an adsorption equilibrium for OCPs between water and particulate organic matter. According to this assumption, the contribution of marine productivity for the sinking of OCPs have been estimated by using TMBR index. The high contribution (>75%) indicated that marine productivity plays a key role for the sinking of OCPs into the marine sediment in the SYS.
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/37059
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:
赵宗山. 利用有机地球化学指标研究 几种入海有机污染物的环境行为[D]. 北京. 中国科学院研究生院. 2016.
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