【作者】 张英；

【导师】 宋金明；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 环境科学， 2010， 博士

【摘要】 本论文聚焦近海典型污染物——重金属(Cd、Zn、Pb、Hg和Cu)与多环芳烃——的生物毒性效应研究,采用现场地球化学调查取样和实验室毒理学研究相结合的研究路线,在系统解析渤海湾典型污染物质(重金属及多环芳烃)含量、分布特征及生态风险评价的基础上,基于“环境浓度水平暴露”的新思路,研究了受试生物体内多种生物标志物对环境浓度水平重金属胁迫的应答及其作用机制；系统研究了在多环芳烃与重金属联合暴露“复合污染”胁迫下,受试生物体内抗氧化指标及代谢酶的表达；通过对海洋环境中多溴联苯醚的集成对比研究,发现了中国某些样品中BDE-183组分比例出现异常高值的现象,首次提出可将该比值用于指示电子垃圾污染源。论文获得了如下一系列新的结论和认识：1.渤海湾海水浓度水平下的Cd和Pb可对扇贝产生明显的氧化压力并引起机体氧化损伤,EROD酶与典型多环芳烃[苯并(a)芘]之间存在良好的剂量-效应关系,重金属与苯并(a)芘在联合暴露“复合污染”胁迫下,扇贝体内生物标志物存在明显的交互作用。(1)渤海湾“复合污染”背景场的解析渤海湾表层海水中重金属Cd、Zn、Pb、Hg、Cu的平均含量分别为0.15μg／L、19.68μg／L、1.63μg／L、4.84×10-2μg／L及2.68μg／L,表底层海水重金属没有明显的差异。渤海湾表层沉积物中重金属Cd、Zn、Pb、Hg、Cu的平均含量分别为0.15mg/kg、26.43 mg/kg、16.28 mg/kg、4.25×10-2 mg/kg、20.80 mg/kg;多环芳烃的含量范围为148.97-375.32ng/g,蒽、芴、苊三种组分占∑PAHs的50%以上；不同环数多环芳烃所占比例为3环(36.49%～83.08%)>5环(10.44%～37.42%)>4环(4.10%～26.35%)>6环(0～24.94%)>2环(0～3.48%)。根据特征比值判断渤海湾表层沉积物中的多环芳烃主要源于草木燃烧。依据ERL、ERM值对渤海湾表层沉积物重金属与多环芳烃潜在生态风险进行评价可知,苊和芴可能会对渤海湾的海洋生物产生负面影响,其它的组分对渤海湾地区的潜在危害较小。(2)扇贝体内生物标志物对单一污染物胁迫的应答渤海湾实际水体环境浓度暴露的重金属对扇贝体内抗氧化体系生物标志物表达的影响各不一致。本研究发现所考察的5种重金属(Cd、Zn、Pb、Hg、Cu)中仅有经Cd、Pb暴露96h后扇贝消化腺内SOD活性显著降低,抑制率分别为16.8%和8.75%,对于CAT与GPx,相较对照组5种重金属暴露均使得酶活性降低,但Cd、Pb的抑制效果最为明显,对于CAT抑制率分别为31.5%、28.7%,对于GPx的抑制率分别为40.4%、62.4%。可见Cd和Pb显著抑制了扇贝体内的各种抗氧化酶指标,增加活性氧对机体产生氧化损伤的发生几率,研究测得经Cd、Pb暴露扇贝体内MDA水平显著升高,诱导率分别达到33.5%和60.2%。可见Cd和Pb对扇贝产生较为明显的氧化压力,而Zn、Hg和Cu对扇贝体内抗氧化指标表达影响并不显著。此外Cd和Pb还对Ⅰ相代谢酶EROD产生明显的抑制作用。苯并(a)芘胁迫扇贝48h、96 h及168 h,对其抗氧化指标及Ⅰ相／Ⅱ相代谢酶产生一定的影响。研究表明扇贝经苯并(a)芘染毒处理之后,暴露组生物体内的EROD、活性均被诱导,且各浓度水平暴露组酶活性基本随暴露时间增加而增加,同一暴露时间下,酶的活性亦随暴露浓度增加而增加,表现出一定的时间-效应关系和剂量-效应关系。当扇贝经高浓度剂量组暴露后其时间-效应关系的相关系数高达0.9996,而当暴露时间长达168 h时其剂量-效应关系的相关系数高达0.9954,这表明当生物体处于苯并(a)芘暴露环境之下,当达到一定暴露时间与暴露浓度,苯并(a)芘对体内EROD的诱导稳定时,该酶可作为生物标志物指示污染状态。另外苯并(a)芘暴露与GST酶活性存在良好的剂量-效应关系,不同的暴露时间其剂量效应关系相关系数均高于0.9961。(3)扇贝体内生物标志物对多环芳烃与重金属联合暴露“复合污染”胁迫的响应当多环芳烃与重金属联合暴露“复合污染”胁迫时,重金对与多环芳烃之间存在一定的交互作用。对EROD、GST和GPx酶活性而言,5种重金属(Cd、Zn、Pb、Hg和Cu)对苯并(a)芘表现为拮抗作用,尤以对EROD酶的作用效果最为明显。单独暴露于苯并(a)芘能够显著诱导EROD酶活性,两种污染物联合暴露的情况下,苯并(a)芘诱导的EROD显著下降,甚至较对照组出现抑制现象,而对SOD与CAT酶活性则无明显的影响。2.通过对海洋环境多溴联苯醚分布、控制因素及组成特征的系统分析,发现中国近海环境样品中BDE-183组分比例异常偏高,或可将其作为特征参数指示电子垃圾污染源。多溴联苯醚因作为阻燃剂广泛使用而对环境产生潜在生态风险,成为一类新的污染物质,论文对海洋环境PBDEs已发表数据进行了系统分析,获得了PBDEs区域分布特征、环境控制因素以及在各种环境介质中PBDEs的同系物组成特征。研究表明海洋环境体系中美国与韩国等区域的沉积物中PBDEs含量水平最高,而欧洲区域相对较低,这与各区域PBDEs的消费能力存在明显的相关关系。通过主成分分析可知近海沉积物中的PBDEs以BDE-209为主,约占总PBDEs的75%以上,而生物样品中则以低溴代同系物为主(BDE-47,-99和-100,三者约占总PBDEs的80%)。BDE-99与BDE-100的比值在营养级较低的生物体内倾向于大于1,而在高等生物体内则小于1,一些以甲壳动物或浮游植物的喂食的生物比值也大于1。值得指出的是,本论文首次报道了中国部分样品中BDE-183组分的比例异常偏高的现象,这或许可以作为特征参数指示电子垃圾污染源。更多还原

【Abstract】 The thesis is focous on the toxic effect of the typical pollutants in coastal zone, such as heavy metals (Cd, Zn, Pb, Hg and Cu) and polycyclic aromatic hydrocarbons (PAHs). Both in field investigation and lab experiment were carried out to systematically study the distribution pattern and Ecological risk assessment of the mentioned pollutants in Bohai Bay. By a hovel research thought of exposure to the environmentally comparative concentration level, we studied the multi biomarker responses to the environmentally relative concentration levels of heavy metal; "Integrated biomarker responses" index has been used to assessment the multi biomarker response research; biomarkers of antioxidant system and metabolic system were investigated to study the combined toxicity of heavy mental and PAHs; basing on the integration study of polybrominated diphenyl ethers (PBDE) in marine environment, a novel phenomena that the ratio of BDE-183 in environmental sample were high in Chinese samples, it can be used as an eigenvalue to indicate the E-waste pollution in this country. Detail of of the thesis have been list as followed,1, Exposing at an environmentally comparative concentration level of Bohai Bay, Cd and Pb have caused a serious oxidative stress in organism; they show good time-response relationship and dose-response relationship between benzo(a)pyrene exposure and EROD activity; interactive effect can be obviously investigated when the bivalves exposed to the benzo(a)pyrene and heavy metals in combinations, which means that heavy metal may have certain effects on the benzo(a)pyrene(1) Environmentally relevant concentration characteristic of "combined pollution" in Bohai BayThe average concentrations of Cd, Zn, Pb, Hg and Cu in surface seawater were 0.15μg/L,19.86μg/L,1.63μg/L,4.84×10-2μg/L and 2.68μg/L, respectively. There was no clear vertical variation characteristic for heavy metal in seawater of this region. In terms of sediment investigation, the concentration level of Cd, Zn, Pb, Hg and Cu in the surface sediment were 0.15 mg/kg,26.43 mg/kg,16.28 mg/kg,4.25×10-2 mg/kg and 20.80 mg/kg, respectively. The concentration range of∑PAHs was 148.97～375.32 ng/g. Among the 16 PAHs individual anthracene, fluorine and acenaphthene were the main components, which contributing over 50%to the∑PAHs. Basing on the ERL (Effects Range Low) and ERM (Effects Range Median) value, the potential biological risk of the mentioned pollutants in sediments can be evaluated. Results indicated that most of the heavy metals and PAHs were higher than ERL values, except fluorine and acenaphthene were ranged between ERL and ERM values which represent a effect-active range.(2) Multi biomarker responses in bivalve to the exposure of heavy metals and benzo(a)pyrene, dosed alone.When bivalves were exposed to the environmental concentration level of heavy metal (Cd, Zn, Pb, Hg and Cu), they had different responses to different heavy metal. Results showed that the activity of SOD had been significant inhibited by 16.8%and 8.75%after 96 h exposure to Cd and Pb. In terms of CAT and GPx, although all of the five metals we investigated have restricted the enzyme activities, Cd and Pb were the most effective ones, with the inhibitions on the CAT of 31.5%and 28.7%, and on GPx of 40.4 and 62.4%. Since they had a profound inhibition effect on the antioxidant enzyme which resulted in oxidative stress, the MDA level in Cd and Pb exposure groups had been elevated by 33.5%and 60.2%, respectively. According to our study, the Zn, Hg and Cu did not have obvious effect on antioxidant system, but Cd and Pb exposure caused a serious oxidative stress in organism, and the two metals have significantly inhibited the EROD activity as well.Bivalves were exposed to low, middle and high concentration of benzo(a)pyrene for 48h,96h, and 168h to study the antioxidant enzyme and phaseⅠ/phaseⅡenzyme response to this typical toxic pollutant. Among all the biomarker, EROD was the most readable for the pollution status of this pollutant, since there are good time-response relationship, and dose-response relationship between benzo(a)pyrene exposure and EROD activity.(3) Multi biomarker responses in bivalve to the exposure of heavy metals and benzo(a)pyrene, dosed in combinationsWhen the bivalves exposed to the benzo(a)pyrene and heavy metals in combinations, heavy metal may have certain effects on the benzo(a)pyrene induced enzymes, in the terms of EROD, GPx, and GST, all of the five heavy metals have exhibited a antagonism effect on benzo(a)pyrene, especially on the EROD. Although exposed to benzo(a)pyrene, dose only, has significant induced of EROD activity, when exposed to the mixture with the five metals all have reduced EROD activity, even exhibited an inhibited effect when compared with that of control. While in terms of SOD and CAT there was no obvious effect caused by heavy metal.2, Basing on investigation of distribution characteristics, controlling factor and congener pattern of PBDEs in marine system, a novel phenomena that the ratio of BDE-183 in environmental sample were high in Chinese samples, it can be used as an eigenvalue to indicate an E-waste pollution in China.PBDEs, due to their widespread usages as flame retardants and their lipophilicity and persistence, have become ubiquitous in the environment. In this thesis, the available data were summarized and analyze to describe the regional distributions, controlling factors and congener patterns of PBDEs in marine and associated environmental matrixes worldwide. Consistent with the production statue, America and Korea are more contaminated than other parts of the world, while Europe is the least contaminated. Based on the Principal Component Analysis, the congener patterns of sediments are different from those of biota. The former are predominant with the heavy brominated congeners (BDE-209 contributing over 85%to the total load) while the latter abounds with the light ones (BDE-47,-99, and-100 taking about 80%). Noticeable,, the relative high proportion of BDE-183 in Chinese sample can prove effectively that China is being polluted by the e-waste received from developed countries.更多还原