【作者】 刘在平；

【导师】 张松林；

【作者基本信息】 西北师范大学 ， 环境科学， 2011， 硕士

【摘要】 环境中有毒有害污染物的种类和数量日益增多,给生态环境和人体健康造成了巨大威胁,如何评价其对生物的影响越来越受到人们的关注。本文通过查阅国内外大量文献,对有毒有害污染物氯苯、间甲酚和城市污水的生态毒性研究进展简要分析发现,与其他众多污染物相比,其毒性较大,但缺乏鱼类的胚胎和仔鱼毒性数据。而作为毒性评价指示生物,斑马鱼胚胎和仔鱼更加方便、灵敏和经济,且与其他毒性数据相关性较好。因此,本文采用斑马鱼胚胎发育技术和静态实验方法,选取上述3种污染物作为受试物,测定其单一毒性及部分污染物的联合毒性,对测定结果进行了定量分析,并对单一污染物斑马鱼仔鱼致死效应建立了参数回归方程。利用斑马鱼胚胎和仔鱼急性毒性测试,研究了氯苯、间甲酚和城市污水3种污染物的胚胎和仔鱼毒性效应,包括亚致死效应和致死效应,以及相应效应各毒理学终点与污染物暴露浓度间的剂量-效应和时间-效应关系,初步揭示了氯苯、间甲酚和城市污水等污染物的毒性效应,以此为进一步开展水生生物生态毒性研究的剂量、时间和毒理学终点选择提供科学依据。具体研究结果如下:(1)用不同浓度的氯苯、间甲酚和城市污水分别对斑马鱼胚胎进行暴露实验发现,不论是单一毒性实验还是联合毒性实验,在不同时刻其对斑马鱼胚胎的毒理学终点不同,如氯苯对胚胎的毒性主要表现为48h水肿,而间甲酚主要表现为对黑色素和黄色素的影响,城市污水则影响胚胎的黑色素、眼点及24h时20s主动运动和血液循环等。此外,在同一时刻、不同浓度的污染物对胚胎的毒性也是有很大差别的。(2)氯苯、间甲酚和城市污水毒性暴露实验中,除每组中最低浓度外,其他各浓度组均造成斑马鱼仔鱼不同程度的死亡、且其参数回归方程各不相同,说明其致毒机理有差异。(3)对氯苯和间甲酚进行联合毒性作用实验,用相加指数法、毒性单位图解法和毒性单位分析法分别评价其对斑马鱼胚胎和仔鱼的毒性。结果表明,在不同时刻和不同浓度下其联合作用类型不同,有时为抗拮作用,有时为相加作用或协同作用,说明其联合作用机理很复杂。(4)实验时选取不同的暴露时刻,所得实验结果相差很大。其中,胚胎和仔鱼暴露于污染物的时间越早,其对污染物的毒性越敏感。更多还原

【Abstract】 The increasing of number and variety of poisonous and harmful pollutants in environment posed a great threat to ecological environment. How to evaluate the influence of these pollutants to creatures aroused more and more attention recently. By consulting a large number of documents at home and abroad, we analyzed briefly the ecological toxicity study progress of chlorobenzene, m-cresol and urban sewage. Compared with other many pollutants, they had higher toxicity, but lack of relevant toxicity data of embryos and larvas of fish. As toxicity assessment, the embryos and larvas of zebrafish have advantages such as convenience, sensitiveness, economy, and good correlation with many other toxicity data. Therefore, this paper used developmental technology of zebrafish embryos and static experiment method, selected three kinds of pollutants mentioned above, tested their single toxicity and joint toxicity of part pollutants, analysed quantificationally the determination results, and established parameters regression equations of lethal effects of single pollutant to zebrafish larvas.Acute toxicity tests were conducted to embryos and larvas of zebrafish. And then, researched the toxic effects, including lethal effects and sublethal effects of chlorobenzene, m-cresol and urban sewage to embryos and fries. The dose-effect and time-effect relationships between each toxicology endpoint for corresponding effect and exposure concentration of pollutants were studied, too. This provided scientific basis for further research on choice of dosage, time and toxicology endpoint in aquatic organisms ecotoxicological study. Meanwhile, toxigenicity mechanisms were revealed preliminarily for chlorobenzene, m-cresol and urban sewage. Especially research results were showed below:(1) Zebrafish embryos were exposed to chlorobenzene, m-cresol and urban sewage of different concentrations respectively, whether single or joint toxicity tests, they both had different toxicology endpionts in different time, for chlorobenzene embryonic toxicity were mainly 48h edema, m-cresol influenced primarily on melanin and uranidin, and urban sewage acted on melanin, eyespots 20s active movement at 24h and blood circulation, etc. In addition, at the same time, pollutants of different concentrations on embryonic toxicity had also greatly distinction.(2) In toxic exposure experiments of chlorobenzene, m-cresol and urban sewage, except for the lowest concentration groups, other various concentrations groups caused different death rates of zebrafish larvas. Their parameters regression equations were different, showed difference in toxigenicity mechanisms.(3) Via joint action experiments of chlorobenzene and m-cresol, toxicities to zebrafish embryos and larvas were evaluated by additive index method, toxic unit graphic method and toxicity units analytical method. The results indicated that it had different effect types in different time and different concentrations, such as antagonistic joint action, sometimes for additional joint action or some synergistic joint action. So, their joint mechanisms were very complex.(4) Choosing different exposure time in experiment, the experimental results had prodigious difference. Experiments showed that the earlier zebrsfish embryos and larvas were exposured, the more sensitive they would be to toxicity of pollutants.更多还原