【作者】 郑曦；

【导师】 韩宝平；

【作者基本信息】 中国矿业大学 ， 环境科学， 2010， 博士

【摘要】 作为南水北调工程东线的调水通道,京杭大运河（苏北段）的水质对东线整体调水水质的影响是十分巨大的。在调水状态下,水体中的化学平衡将被打破,并产生一系列的化学过程。本论文在江苏省自然科学基金的资助下,于2009年7月-2010年2月采集京杭大运河（苏北段）河水及表层沉积物96个样品,过水湖泊湖水及表层沉积物58个样品,合计共154个样品,对京杭大运河（苏北段）水体中多环芳烃的分布特征、污染程度和底泥中多环芳烃（PAHs）的释放动力学规律进行了系统研究,得出下列研究成果:1.京杭大运河（苏北段）水体底泥与河水中PAHs的平均含量为5239ng/g和5984ng/L,均处于中等污染水平,总有机碳是影响PAHs在不同地段沉积物中分布的主要因素;不同地段水体中PAHs的含量由高到低排列:徐州段>淮安宿迁段>扬州段,微山湖>洪泽湖>骆马湖。丰水季节水体中的PAHs含量大于枯水期,京杭大运河（苏北段）水体中的PAHs将会对调水的水质产生较大的影响。2.通过比值法与主成分因子分析法对京杭大运河（苏北段）水体中PAHs的来源进行解析得知:煤炭、木材的燃烧,机动船的燃油排放以及周边农田作物焚烧等人类活动的影响是苏北大运河（苏北段）多环芳烃的主要来源,煤炭燃烧与炼焦生产的排放对京杭大运河（苏北段）河道中PAHs的影响最大,贡献率达到93%。3.利用沉积物质量基准法（SQGs）和商值法（HQ）对京杭大运河（苏北段）与过水湖泊水体中的PAHs进行了风险评价,结果表明严重的多环芳烃生态风险在京杭大运河（苏北段）中不存在,但淮安宿迁段底泥中DahA、徐州段底泥中Ace、Phe、Ant和DahA的含量均超过ERM值（分别是275ng/g、1187ng/g、1639 ng/g、1228ng/g和340 ng/g）,发生生物毒性效应的概率较高;水体中BaP的含量数倍高于其生态基准值,存在潜在的生态风险。4.不同粒径沉积物中PAHs的含量与粒径大小成正相关,粒径中TOC含量是影响PAHs在不同粒径沉积物中分布的主要因素, TOC和粒径大小呈显著正相关,相关系数r2为0.8749。5.利用自制装置模拟了不同情况下河道底泥中多环芳烃的释放特征,实验结果表明:底泥PAHs的释放有一个快速释放的阶段,随后进入缓慢释放阶段;控制底泥PAHs释放的影响因素按其影响程度大小分别是底泥有机碳含量、扰动、温度、PH值;多次换水清洗可以对水体的PAHs内源污染起到一定的控制作用,但不能根本消除污染沉积物对水质的影响。依据实验结果,建立了底泥中某些单体PAHs向上覆水释放的动力学模型:C_w= [1-Fe^-K1t-（1-F）e^-K2t]×B（式中B是与底泥中该PAHs的初始含量、两界表面积和水相的体积有关的一个常数）,并得出静止与扰动状态下,不同单体PAHs的K1和K2的值。该论文有图34幅,表55个,参考文献228篇。更多还原

【Abstract】 Beijing-Hangzhou Grand Canal (Subei Section )is the east route of Water Transfer Project from South to North in China, which water quality will significantly affect the efficiency of Water Transfer Project from South to North. With the water transferred, the chemical balance in the water of The Grand Canal will change, and a series of chemical processes will happen. With the aid of Jiangsu nature science fund, we collected 96 samples of Beijing-Hangzhou Grand Canal (Subei Section ),and 58 samples of three storage lakes.We focused on the distribution,source apportiment and assessment of PAHs in surface sediments and water of Beijing-Hangzhou Grand Canal (Subei Section ), we also researched the release kinetics of PAHs in the sediments of Beijing-Hangzhou Grand Canal (Subei Section ).The main conclusions of this work were as follows:(1) The average total concentrations of 16 PAHs in sediment and water from Beijing-Hangzhou Grand Canal (Subei Section ) were 5239ng/g and 5930 ng/L , which were in moderate level compared with other waters. TOC was important for PAHs distribution in sediments. The concentrations of PAHs in different section arranged from high to low: Xuzhou section>Huaian-Suqian section>Yangzhou section,Weishan lake>Hongze lake>Luoma lake. The PAHs concentrations of water were higher in flood seasons than that in dry seasons,the PAHs in the watercourse Beijing-Hangzhou Grand Canal (Subei Section ) will significantly affect the efficiency of Water Transfer Project from South to North.(2) Ratios of Phen/Ant、Fla/Pyr , Sources apportionment by principal component analysis reflected that PAHs in Beijing-Hangzhou Grand Canal (Subei Section) were mainly from coal ,coke,firewood and petroleum and diesel oil combustion. The main sources of PAHs in Hongze lake, Luoma lake and Weishan lake were mainly from coal,firewood and petroleum and diesel oil.(4)The ecological risk of surface sediment and water in Beijing-Hangzhou Grand Canal (Subei Section) was assessed with the methods of sediment quality guidelines (SQGs) and HQ, respectively. The results showed that the concentration levels of PAHs in the study area have not caused the marked negative influence on organism. However DahA compound in Huaian-Suqian section sediment and Ace, Phe, Ant and DahA compounds in Xuzhou section sediment were present in excess of the moderate ERM, BaP in water were present in excess of the Ecological criteria of PAHs in water, and the biological effects exist.(5) TOC was important for PAHs distribution in sediments. Additionally, sediment organic matter type and structure also played an important role in PAHs distribution in different grain size fractions. Release kinetics of PAHs in the sediments were studied by experiments. The release rules were studied under static and suspended water conditions. The results showed that there were faster release speeds at the beginning of the experiment,and the release speeds slow down gradually with the increasing time. The factors that influence the release of PAHs from the sediment arranged from high to low: The concentration of TOC in the sediment, suspended condition, the temperature and pH.The PAHs concentrations in the water could effectively reduced after 5 times water-exchange, but at last the PAHs concentrations in the overlying water will keep stable levels because of the release from the sediments. A release kinetic model of PAHs from aquatic sediments was set up on the basis of these data. Cw= [1-Fe-K1t-(1-F)e-K2t]×B. The test result showed that the simulation data by the kinetic model can well fit the measure data, so the model can be used to describe the release kinetic proeess of PAHs from the sediments to water.更多还原