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毛白杨和芦苇对多氯联苯的植物修复效应研究

标题: 毛白杨和芦苇对多氯联苯的植物修复效应研究
英文标题: Phytoremediation of Polychlorinated Biphenyls by Populus Tomentosa Carr and Phragmites Australis (Cav.) Trin. Ex Steud
作者: 李铮
出版时间: 2012-01-01
所在大学: 河北农业大学
关键词: 多氯联苯,毛白杨,芦苇,生物修复
英文关键词: Polychlorinated biphenyls,Populus tomentosa Carr,Phragmites australis (Cav.) Trin. ex Steud,bioremediation,remediation
论文级别: 硕士
学位: 学位论文
导师: 杜克久%傅珊
专业: 林木遗传育种
提交时间: 2012
摘要: 多氯联苯(Polychlorinated biphenyls,PCBs)是一类典型的持久性有机污染物(Persistant Organic Pollutants,POPs).作为首批被列入斯德哥尔摩公约中优先控制的12类持久性有机污染之一,PCBs具有致癌,致畸,致突变等多种毒性效应,并通过食物链富集和生物放大作用,引发人和动物免疫系统疾病,严重威胁人民的生命健康.目前生物修复技术因其经济可行已经成为国内外的研究热点,本研究以我国常见植物毛白杨和芦苇作为研究对象,通过PCB3进行两个浓度(20μg/mL和2μg/mL)暴露试验研究杨树和芦苇对PCBs的富集和降解效应.主要结果如下:1.通过对毛白杨和芦苇进行两个浓度(20μg/mL和2μg/mL)暴露试验,发现PCBs在毛白杨和芦苇各器官中存在明显的分布差异.其中在高浓度(20μg/mL)暴露试验中,毛白杨器官中PCBs的含量表现为根>叶>茎,芦苇器官中PCBs的含量表现为根>茎>叶;在低浓度(2μg/mL)暴露试验中,毛白杨器官中PCBs的含量表现为叶>根>茎,芦苇器官中PCBs的含量表现为根>叶>茎.分析原因后发现:植物器官内的PCBs含量与暴露浓度和植物叶片的结构可能有有直接关系.2.分析两个浓度暴露下,PCBs中各氯代物在毛白杨和芦苇中的比重发现:毛白杨和芦苇器官中2氯、3氯和4氯的比重大于PCB3,而5氯(包括5氯)以上的高氯代物的比重远远低于PCB3.所以推测毛白杨和芦苇器官可能将PCBs中的5氯以上(包括5氯)的高氯代物通过脱氯作用降解为低氯代物,而且脱氯作用也可能随着暴露浓度的增大而增大.3.试验以PCB81、PCB118、PCB105和PCB157为研究对象,研究毛白杨和芦苇组织内共平面PCBs的生物修复效应.研究发现:低浓度暴露时,dl-PCBs在芦苇器官的含量顺序为根>茎>叶,dl-PCBs在毛白杨器官的含量为叶>根>茎;高浓度暴露时,dl-PCBs在芦苇器官中的含量顺序为根>茎>叶,dl-PCBs在毛白杨器官中的含量为根>叶>茎.分析认为毛白杨和芦苇对dl-PCBs的吸收可能与暴露浓度和植物叶片结构有关.4.通过对比高浓度和低浓度暴露时毛白杨和芦苇器官中dl-PCBs的比重,发现除了低浓度暴露时芦苇根内PCB105的比重大于PCB3外,其它器官和浓度的dl-PCBs均小于PCB3中的比重.分析认为芦苇和毛白杨各器官均可能对dl-PCBs有一定的修复作用.5.通过对毛白杨和芦苇植物各器官内PCBs的组成分分析,推测毛白杨和芦苇对PCBs有一定的生物修复效应.
英文摘要: Polychlorinated biphenyls (PCBs) were listed along with 11 other compounds as persistent organic pollutants (POPs) by the Stockholm Convention on 22 May 2001. PCBs are stable in the environment, can undergo long-range atmospheric transport, and can bioaccumulate through the food chain. Exposure to PCBs can result in a broad spectrum of health effects, and the next generation hormonal dysfunctions. Epidemiologic evidence indicated that PCBs caused various kinds of cancer by the International Agency for Research on Cancer (IARC). In recent studies on human health regarding PCBs exposure, more studies have focused on the bioaccumulation of congener-specific levels. This trend is due to the development of new technology that enabled the determination of trace amounts of specific PCB congeners in environmental and biological samples with superb sensitivity and reliability. On the other hand, efforts to improve bioremediation have been evolving over the last several decades. Present research is focoused on the investigation of bioaccumulation and remediation of PCBs ( 20μg/mL and 2μg/mL) in poplar and reed.In the high concentration (20μg/mL) exposure experiment, content of PCBs in the poplar organization showed concentrations in an order of root>leaf>stem. Moreover, content of PCBs in the reed organization also showed concentrations in an order of root>stem>leaf. In contrast, in the low concentration (2μg/mL) exposure experiment, content of PCBs in the poplar organization showed concentrations in an order of leaf>root>stem. Furthermore, content of PCBs in the reed organization also showed concentrations in an order of root>leaf>stem.Of the PCB homologues, the dominant PCBs detected in the poplar and reed were tri-CBs, followed by tetra-CBs and di-CBs. Higher-chlorinated congeners from the poplar and reed were much lower than those obtained from PCB3.In this study, PCB81、PCB118、PCB105 and PCB157 were focused on the behalf of dl-PCBs. In the low concentration exposure experiment, content of dl-PCBs in the reed organization showed concentrations in an order of root>stem>leaf. Furthermore, content of PCBs in the poplar organization showed concentrations in an order of leaf >root>stem. In contrast, in the high concentration exposure experiment, content of dl-PCBs in the reed organization showed concentrations in an order of root>stem>leaf. Moreover, content of dl-PCBs in the poplar organization showed concentrations in an order of root>leaf >stem.By the comparison of dl-PCB ratios in the exposure experiment (20μg/mL and 2μg/mL), it is evident that dl-PCBs from the poplar and reed were much lower than those obtained from PCB3, except for PCB105. With the increase in exposure concentration, the dl-PCBs proportion of reed and poplar organization decreased significantly