【作者】 吴玲玲；

【导师】 陈玲； 张亚雷；

【作者基本信息】 同济大学 ， 环境科学， 2007， 博士

【摘要】 河口区是人类活动与海陆相互强烈作用的典型地带。长江口是我国的第一大河口。近年来，由于经济的快速发展和人口高度密集，越来越多的污染物进入长江，导致长江口水体的生态环境逐渐恶化。持久性有机物污染由于具有长期残留性、生物积累性、长距离迁移性和高致毒性等特点，而成为目前备受世界关注的环境问题。本文以低分子量多环芳烃和有机氯农药为研究对象，分析其在长江口水—沉积物两相介质中的含量和分布特征；在此基础上，选取长江口水体中这两类POPs物质污染较严重的菲和林丹，在实验室进行鱼类毒理学试验，分别模拟长江口水体中的污染浓度以及亚致死浓度对毒理学模式鱼(斑马鱼(Brachydanio rerio))和长江鱼类(黄颡鱼(Pelteobagrus fulvdraco))的毒性效应，并探讨了这些毒理学指标对长江水体中多环芳烃和有机氯农药污染的指示作用；同时利用斑马鱼胚胎对长江口沉积物的污染水平进行评价。主要得到以下几条结论：(1)对长江口水体中的低分子量多环芳烃(LMW PAHs)的含量和分布特征进行了初步研究，结果表明：长江口水体中萘、芴、菲、蒽4种LMW PAHs的总浓度在平水期为64.28～102.59ng／L，平均浓度为80.24ng／L。丰水期为146.46～411.86ng／L，平均浓度为292.36ng／L。与国内外重要河流相比，其污染处于中等偏下水平。表层水体中LMW PAHs的分布主要受人类活动影响，在监测的6个国控断面中，南通和徐六泾断面污染较严重。平水期和丰水期水体中的PAHs可能来自于居民生活燃气和燃煤及生活污水、工业污水，也可能来源于机动船只的含油废水排放和燃料油的燃烧及泄漏。枯水期的多环芳烃污染主要来自于燃烧。平水期和丰水期水体中的PAHs均以菲和萘为主要污染组分。水体中LMW PAHs的含量受季节变化的影响，PAHs的含量为丰水期＞平水期。(2)对长江口水体和沉积物中的有机氯农药的含量和分布特征进行了初步研究，结果表明：长江口表层水体中有机氯农药的浓度范围在平水期为2.63～30.53ng／L，平均浓度为15.42 ng／L；枯水期为2.30～16.01ng／L，平均浓度为8.64ng／L；丰水期为22.66～153.90ng／L，平均浓度为65.25ng／L。与国内外重要的河流相比，长江口水体中有机氯农药的污染程度属于中等水平。表层沉积物中有机氯农药的污染水平较低。对有机氯农药的组成特征的分析表明，长江口水体的DDTs大部分已经降解，以残留的DDT和其降解产物为主要组分。水体中的HCHs还没有完全降解，且近期内水体中存在林丹的输入。丰水期水体中有机氯的浓度要明显高于平水期和枯水期。(3)林丹是构成长江口水体中有机氯农药的重要组分。将斑马鱼分别暴露在浓度为0.01，1.0和100.0μg／L的林丹水溶液中36d，以研究林丹对斑马鱼(Brachydanio rerio)的组织结构的影响，结果表明：浓度为0.01μg／L的林丹溶液暴露下，未对斑马鱼的鳃和肝组织造成明显的损伤。暴露在浓度为1.0μg／L和100.0μg／L的林丹的水溶液中36d，斑马鱼的鳃和肝组织结构变化显著，斑马鱼鳃组织变化为：上皮细胞残损、脱落，鳃小片上皮细胞水肿，柱细胞变形。斑马鱼肝组织变化为：部分肝细胞肿大，细胞核萎缩变形或偏离细胞中心，胞质疏松，空泡明显增加，细胞质中可见脂沉积。暴露在100.0μg／L的林丹溶液中，其鳃和肝组织结构受到的损害更为严重。斑马鱼的鳃和肝组织病理学指标可以作为指示水体中林丹污染的生物标志物。长江口水体中林丹的污染浓度下短期暴露，未对斑马鱼的鳃和肝组织造成损害。(4)菲是构成长江口水体中多环芳烃污染的重要组分。将斑马鱼分别暴露在浓度为0.05和100.0μg／L的菲的水溶液中36d，以研究菲对斑马鱼(Brachydanio rerio)的组织结构的影响，结果表明：斑马鱼的鳃和肝对水体中的菲反应敏感，浓度为0.05μg／L的菲已经对斑马鱼的鳃、肝产生毒性效应，表现为发生鳃小片上皮细胞肥大和水肿；肝细胞发生肿大，胞质产生空泡，影响了其呼吸代谢和肝的物质合成与转运功能的发挥。伴随菲浓度的升高。菲浓度达到100.0μg／L时，斑马鱼的鳃和肝受到损伤加重：鳃丝上皮增厚、鳃小片上皮隆起。肝细胞变得不规则，细胞核萎缩变形和偏离细胞中心，部分肝细胞空泡化程度加重，发生核溶解或细胞溶解造成局部肝组织坏死。斑马鱼的鳃和肝组织病理学指标可以作为指示水体中菲污染的生物标志物。长江口水体中菲的污染水平已经对斑马鱼的鳃和肝组织产生了一定的毒害，应引起有关部门的高度重视。(5)实验室人工繁殖底栖性鱼种黄颡鱼(Pelteobagrus fulvidraco)，模拟长江水体中菲的污染水平以及亚致死浓度对黄颡鱼幼鱼肝脏的抗氧化酶活性的影响。结果显示：菲对黄颡鱼肝脏中CAT活性表现为抑制作用；对GPx活性主要表现为诱导作用；较低浓度(0.05μg／L)的菲胁迫下，SOD活性表现为诱导效应，较高浓度(100μg／L)的菲胁迫下，SOD活性表现为先抑制后诱导效应；CAT活性对菲的胁迫相对更敏感。黄颡鱼肝脏中的抗氧化酶活性可以作为生物标志物来评价长江口水体的菲的污染程度。长江口水体中的菲的污染水平已经对黄颡鱼肝脏中的抗氧化酶活性产生了影响。(6)斑马鱼胚胎致畸技术是各国际标准组织认可的标准毒性测定方法之一。本论文采用斑马鱼胚胎发育技术，对菲的毒性进行测定，并筛选出胚胎发育过程中的敏感性指标，用来指示水体中菲的污染程度。结果表明，斑马鱼胚胎可以作为水体中菲污染的生物标志物。在囊胚期进行染毒，斑马鱼胚胎对菲的毒性作用最敏感。96h孵化率、48h致死率、24h卵凝结和96h致畸率4项指标可以指示水体中菲污染的程度。它们对菲的敏感性为：96h孵化率指标＞48h致死率＞24h卵凝结＞96h致畸率。目前，长江口水体中菲的污染水平没有对斑马鱼的胚胎发育产生明显的毒性效应。(7)沉积物是河口地区水体中污染物质的“汇”。较水质分析而言，对沉积物的污染状况进行分析和评价更能代表河口区污染水平。本论文利用斑马鱼胚胎发育技术通过直接接触暴露法和萃取有机物暴露法对长江口的沉积物的毒性进行了评价。结果表明：长江口沉积物(浓度为430mg／mL(水))通过直接接触暴露对斑马鱼胚胎的致死率为9.33(±2.31)～38.67(±2.31)％，致畸率为1.33(±2.31)～9.33(±2.31)％。萃取有机物暴露法(浓度为60mg／mL(水))对斑马鱼胚胎的致畸率为4.71(±2.08)～11.81(±2.41)％。萃取有机物暴露法比直接接触暴露法对斑马鱼胚胎的致畸效应要强烈。南通、徐六泾、石洞口断面的沉积物对斑马胚胎的毒性作用较强，南港、吴淞口下23km、北港的沉积物对斑马胚胎的毒性作用较弱。长江口沉积物中萃取出的有机污染物已经对斑马鱼胚胎产生了致死和致畸效应，说明长江口沉积物中的有机污染物对水生生物具有潜在的毒性，应加强对长江口水体中有机污染物的控制。更多还原

【Abstract】 The Yangtze River is the longest river in China and the third longest in the world.Polycyclic aromatic hydrocarbons （PAHs） and organochlorine pesticides wereimportant persistent organic pollutants. The aim of this study is to examineorganochlorine pesticides and low molecular weight polycyclic aromatichydrocarbons （LMW PAHs） distribution in water from the Yangtze River estuary andtry to develop a set of biomarkers to indicate PAHs and OCPs pollution level in thefollowrag study areas. The histopathologic and embryonic biomarkers of zebrafish（Brachydanio rerio） and Yellow cartfish （Pelteobagrus fulvidraco） were used toassess the toxicology of organochlorine pesticides and LMW PAHs in water andsediment of the Yangtze River estuary. The results of the present research areas asfollows:（1） The concentration and distribution of LMW PAHs, i.e., naphthalene,fluorene, phenanthrene and anthracene were monitored in November 2005, Marchand July 2006 in the water of the Yangtze River. The LMW PAHs in the aqueoussamples were extracted via C-18 solid phase extraction cartridges （SPE） andquantitatively determined by high performance liquid chromatography with ultraviolet detection and fluorescence detection （HPLC-DAD/FLD）. Comparing withthose of other rivers in China, the mean concentration of PAHs in the Yangtze Riverwas of moderate level. The concentration of PAHs in the surface water of NT andXLJ were higher than other sites in the Yangtze River estuary. The individualcomposition of PAHs was characterized by naphthalene, and phenanthrene was thesecondary component in high flow season. However, the individual composition ofPAHs was characterized by phenanthrene, and naphthalene was the secondarycomponent in normal flow season. The ratios of phenanthrene to anthracenesuggested that PAHs in the water were derived from many sources in high flowseason and normal season. And PAHs were derived from combustion of fossil fuels inlow flow season. The seasonality of the mass concentration of PAHs was significant,and the level of PAHs in high flow season was higher than that in low flow seasonand normal season. （2） 7 kinds of organochlorine pesticides （OCPs, including HCHs and DDTs） inwater from the Yangtze River were determined by using solid phase microextraction（SPME）-gas chromatography with electron capture detector. Compared with otherrivers in China, the mass concentration of OCPs in the water of the Yangtze Riverwas of moderate and a bit higher level. However, the concentration in the sedimentwas of lower lever. HCHs had higher mass concentration than DDTs. Distributioncharacteristics of OCPs components showed there were some new input oflindane（γ-HCH） in near term at most sections. Mass concentration of OCPs in waterwas distinguishing at different season, which was higher in high flow season than inlow season and normal season. Agricultural runoff and soil denudation enhanced inhigh flow season, and took more OCPs into the Yangtze River.（3） Water pollution induces pathological changes in fish. As an indicator ofexposure to contaminants, histology represents a useful tool to assess the degree ofpollution, particularly for sublethal and chronic effects. In this papers,histopathological effects of lindane and phenanthrene on gill and liver of zebrafish（Brachydanio rerio） were determined by light microcope, respectively. The fish wereexposed to the different concentrations of lindane（0, 0.01, 1.0 and 100.0μg/L） andphenanthrene （0, 0.05 and 100.0μg/L） for 36 days. There were no pronouncedhistopathological alterations in gill and liver of fish exposed to 0.01μg/L lindane,which suggested there were no evident effect on gill and liver of fish of lindane levelin the Yangtze River estuary. The common gill alterations at 1.0 and 100.0μg/L lindanwere desquamation of epithelial cell, hypertrophy of epithelial cells and deformationof pillar cells. Exposed to 1.0 and 100.0μg/L lindane for 36d, hepatic lesions in liverwere characterized by hepatocyte hypertrophy, nuclear atrophy and deformation,vacuolization, focal necrosis and lipidosis. The histopathological changes in gill andliver tissues of Brachydanio rerio were sensitive to phenanthrene exposure. It hadalready had toxic action on gill and liver of fish exposured to 0.05μg/L phenanthrene,which suggested the toxic action of phenanthrene level in the Yangtze River estuaryon gill and liver of fish. In the gills epithelial hypertrophy and edema were observed,in the liver there were hypertrophy of hepatocytes and vacuolization. After exposureto 100.0μg/L phenanthrene for 36 days, the lesions in gill were characterized by thickening of the filament epithelium and lifting of the lamellar epithelium; In theliver the shape of hepatocytes were irregular, some nuclei were atrophy anddeformation or in a lateral position close to the cell membrane, hepatocytes werehighly vacuolated, and focal necrosis occurred after cytolysis and karyolysis.Impairments of gill and liver of fish increased with increasing concentrations ofchemicals. The histopathological effects on gill and liver of zebrafish could also beused as a biomarker and an early warning indicator of PAHs and lindane pollution.（4） The juvenile Yellow cartfish, Pelteobagrus fulvidraco, which was artificialpropagated in our laboratory, was exposed to phenanthrene at environment level inYangtze river （0.05μg/L）and sublethal concentration（100μg/L） for 0.25, 1, 3, 7,14days in experimental condition to investigate the effects on the main antioxidantenzymes: superoxide dismutase （SOD）, catalase （CAT） and seleniumdependentglutathione peroxidase （GPX） in the liver of fish. The results showed that SOD andCAT and GPX content in the liver of Pelteobagrus fulvidraco were significantlyrelated to phenanthrene pollution level in water. After low concentration ofphenanthrene exposure, more superoxide radicals could be produced, and theactivities of hepatic SOD were significantly induced, and the generation of O₂^·- waswithin the SOD elimination capacity. Otherwise, with the concentration ofphenanthrene up to the certain extent, the O₂^·- generation increasing and exceeds thefunction of SOD elimination, the O₂^·- as well as other oxyradicals can inversely insultthe enzyme to make it inactivated. The GPX content in the liver of Pelteobagrusfulvidraco exposed to phenanthrene was principally induced, and CAT activities weresuppressed during early days. With the prolonged exposure, the antioxidant enzymesactivities were up to the control value. All the results showed that CAT activity in fishliver were more sensitive to phenanthrene exposure, therefore, they could also beused as a biomarker and an early warning indicator of phenanthrene pollution.（5） The embryo development technique in zebrafish, Brachydanio rerio, is atoxicity testing method making use of sensitivity of fish embryo development in earlystage to study and evaluate the specific effecting mechanism, the most sensitiveeffecting time, embryo toxicity and teratogenicity of chemicals through observing thedevelopment process of zebrafish embryo after chemicals exposure to fertilized ova. This technique was used to test toxicity of phenanthrene in this papers. The resultsshowed that phenanthrene could markedly inhibit the development of Brachydaniorerio embryos, and caused its malformation and even death. There were differenttoxicity endpoints which could be observed in embryos exposed to phenanthrene withdifferent time. And the most sensitive effect duration of phenanthrene was blastulastage The acute toxicological endpoint of Brachydanio rerio embryos was in order of96h hatching rate＞48h lethal rate＞24h coagulated eggs＞96h abnormalities. Theembryo development of zebrafish could also be used as a biomarker of PAHspollution.（6） The suitability of a sediment contact assay using zebrafish （Brachydaniorerio） embryos to evaluate the degree of sediment contamination in Yangtze Riverwas investigated in this papers. Fertilized zebrafish eggs were exposed to both thewhole and organic extract concentrations prepared from collected sediments from 6sites along Yangtze River （from Nanjing to Shanghai）. The different toxicityendpoints, such as mortality, abnormality, heart rate, and hatching rate in thedeveloping embryos were recorded during a 96h exposure. The results showed thatthe embryotoxic of sediment in Yangtze river was NT, XLJ and ZY were moreseverer than SDK, NG and BG, and teratogenic responses in embryos exposed toorganic extracts were more severe than whole sediment exposure. Furthermore,embryotoxic responses by zebrafish embryos to sediment exposures were alsodiscussed in relation to the analyzed contaminants in the sediments （heavy metals,PAHs, DDT, HCH, solvent）. Overall, the present study points out that the sedimentcontact assay with zebrafish embryos offers a practicable and highly sensitivebioassay for the general assessment of sediment toxicity of Yangtze River estuary.更多还原