【作者】 王益民；

【导师】 张迎梅；

【作者基本信息】 兰州大学 ， 动物学， 2010， 博士

【摘要】 在兰州和白银地区,每天都有大量的污染物被排入黄河,造成了黄河兰州段水体不同程度的污染,必然会影响到生活在其中的鱼类等水生生物。依赖于黄河生活的人们的身体健康也会受到威胁。控制水体污染非常重要,准确评估水体污染程度,是治理和改善黄河兰州段水质的前提。研究污染水体对鱼类产生的毒性效应,能直接反映水体的污染程度,有助于评估污染水体给人类带来的健康风险。利用鱼类监测水体污染可以补充常规水质监测的不足。本研究以黄河兰州段常见的两种土著鱼类——黄河高原鳅(Triplophysa pappenheimi)和黄河(?)(Gobio hwanghensis)为材料,研究黄河兰州段污染水体的毒性效应,并利用鱼类不同层面对污染的响应评价污染状况。首先,通过筛选鱼体内的有机污染物,测定重金属(Cu、Pb、Zn、Cd)在鱼类组织(肝、肾、鳃、肌肉)中的含量,研究污染物在鱼体内的富集状况；其次,通过测定鱼类肝、肾、鳃组织中总抗氧化能力(Total anti-oxidant capacity, T-AOC)和丙二醛(Malondialdehyde, MDA)含量,分析鱼类红细胞微核率(Micronucleus, MCN frequency)和肝、肾、鳃组织细胞的DNA损伤程度,观察鱼类肝、肾、鳃、肠组织结构的变化,确定污染水体对鱼类的毒性效应；最后,根据实验研究结果,总体评价黄河兰州段水体的污染状况。研究结果如下：1.有机污染物定性分析。用GC/MS技术在T.pappenheimi肝脏内检测出了8种有毒有机污染物,分别是硝基苯(Nitrobenzene)、四氯化碳(Carbon Tetrachloride)、1,4-二噁烷(1,4-Dioxane)、甲苯(Toluene)、N-苯基-2-萘胺(2-Naphthalenamine)、正十四烷(Tetradecane)、正十八烷(Octadecane)、正二十烷(Eicosane)等,它们均具有致癌、可疑致癌或促癌性质。2.黄河兰州段重金属污染评价。黄河兰州段兰州和白银两地,Cu、Pb、Zn和Cd在水体中的浓度均未超过中国《地表水环境质量标准》(GB 3838-2002)中Ⅲ类水质的评价标准,在底泥中的浓度均未超过美国国家海洋和大气管理局(NOAA)的泥沙质量评价标准中的低浓度效应范围值,在两种鱼肌肉中的含量未超过中国《农产品安全质量无公害水产品安全要求》(GB 18406.4-2001)中规定的质量标准。3.黄河兰州段兰州和白银两地重金属污染程度比较。水体中,白银样点Cu、Pb、Zn、Cd的含量显著高于兰州样点(P<0.05),Pb在白银样点的浓度超过了中国《生活饮用水卫生标准》(GB 5749-2006)中规定的最大值。底泥中,白银样点的Cu和Cd的含量显著高于兰州样点(P<0.05),Pb的含量显著低于兰州样点(P<0.05)。Ghuanghensis组织内,白银样点的Cu、Zn含量和兰州样点无显著差异(P>0.05),白银样点Cd的含量显著高于兰州(P<0.05),白银样点Pb的含量显著低于兰州(P<0.05)。4.重金属在两种鱼组织中的分布规律。重金属在T.pappenheimi和Ghwanghensis两种鱼内脏中的含量均高于肌肉中的含量,其中Cu和Pb在肝脏中的含量较高,Zn在鳃中的含量较高,Cd在肾脏中的含量较高。5.污染水体对鱼类的毒性效应。生活在污染河段的鱼类,其肝、肾、鳃组织中T-AOC显著低于对照样品(P<0.05),MDA含量显著高于对照样品(P<0.05),MCN和DNA损伤程度显著高于对照样品(P<0.05)。经组织学观察,其肝、肾、鳃、肠等组织,未见明显病理学改变。总之,黄河兰州段水环境中存在多种具有致癌、可疑致癌或促癌性质的污染物,该段水环境具有致癌风险,但黄河兰州段重金属污染程度在白银和兰州地区两地均未及严重水平；Pb在白银水体中的含量较高,作为饮用水源可能会给人类带来健康影响；黄河兰州段水体中的污染物在鱼类组织中的富集,对鱼类造成了氧化胁迫效应,损伤了鱼类遗传物质,但尚未对鱼类组织结构产生影响。T.pappenheimi和G. hwanghensis的肝和肾对重金属具有较强的富集能力,可用于监测黄河上游重金属污染。T. pappenheimi组织的T-AOC、MDA、MCN、DNA损伤程度等指标综合反映了黄河水质污染状况,是较为理想的生物标志物,可用于监测黄河上游水体污染。更多还原

【Abstract】 Large numbers of pollutants are discharged into the Yellow River in Lanzhou and Baiyin region every day, which makes the river polluted seriously. Inevitably, organisms including fish species are affected adversely, and health of residents relying on the river for water supply are threatened, either. It is very important to control of the water pollution. Whereas, evaluating water quality precisely is the premise of water pollution control. The toxic effects of polluted water on organisms could reflect the condition of water pollution, and it is helpful to make the risk assessment of polluted water for human being. Using fish to monitor water pollution would supplement the routine water monitoring.In this study, two dominant endemic fish species, Triplophysa pappenheimi and Gobio hwanghensis, both common in Lanzhou section of the Yellow River, were chosen as target species for evaluating the toxic effects of polluted water.First, the toxic organic pollutants in fish tissues were identified qualitatively and the concentrations of heavy metal (Cu, Pb, Zn and Cd) in fish tissues (liver, kidney, gill and muscle) were determined quantitatively.Second, the toxic effects of polluted water on fish were evaluated by determining the total anti-oxidant capacity (T-AOC) and the level of malondialdehyde (MDA), by statisticly analyzing of the micronucleus frequency (MCN), and the degree of DNA damage, and by the histological observation.Last, the evaluation of polluted condition in Lanzhou section of the Yellow River and risk assessment for human being were conducted based on the presence of toxic organic pollutants, the concentration of heavy metals in fish tissues, and the variation of fish oxidative stress markers (T-AOC and MDA), genetic material damage markers (MCN and DNA damage) and pathological observation. The results showed that:1. Qualitative analysis of organic pollutants:eight kinds of toxic organic pollutants in liver of T. pappenheimi were found by means of GC/MS, which were: Nitrobenzene, Carbon Tetrachloride,1,4-Dioxane, Toluene,2-Naphthalenamine, Tetradecane, Octadecane and Eicosane. These pollutants have been considered as carcinogen, suspected carcinogen or carcinogenic promoting agents. 2. Evaluation of heavy metal pollution in Lanzhou section of the Yellow River:Both in Lanzhou and Baiyin, Cu、Pb、Zn and Cd concentrations in water body met the third-class water quality standard restricted in Environmental quality standards for surface water (GB 3838-2002). In sediment they did not exceed the effects range-low values described by the National Oceanic and Atmospheric Administration of America.In fish muscles they did not exceed evaluation criteria limited in Safety qualification for agricultural product for non-environmental pollution aquatic products (GB 18406.4-2001), respectively.3. Comparison of heavy metal pollution between Lanzhou and Baiyin:In water body, Baiyin Cu, Pb, Zn and Cd concentrations were significantly (P<0.05) higher than those in Lanzhou, Pb concentration exceeded the maximum permitted level prescribed in Standards for Drinking Water Quality (GB 5749-2006). In sediment, Baiyin samples contained higher concentrations of Cu, Cd and lower concentrations of Pb than those in Lanzhou sediment (P<0.05). In G. hwanghensis tissues, Cu and Zn levels in fish obtained from Baiyin were similar to those from Lanzhou(P>0.05), Baiyin fish contained significant higher Cd and lower Pb concentrations than those in Lanzhou fish (P<0.05).4. Distribution patterns of heavy metal in fish tissues:heavy metal concentrations in inner organs were all higher than those in muscles. Cu and Pb were found highly accumulated in liver, Zn in gill and Cd in kidney.5. Toxic effects of polluted water on fish:T-AOC in liver, kidney and gill were significantly lower than that in the same tissue of control samples (P<0.05), while the MDA level, MCN frequency and DNA damage were all significantly higher than that in the same tissue of control samples (P<0.05). Obvious pathological changes in liver, kidney, gill and intestines were not observed.In conclusion, the presence of carcinogen, suspected carcinogen or carcinogenic promoting agents in fish tissues indicated that the polluted water in Lanzhou section of the Yellow River may bring cancer risks to organisms including human being. Lanzhou section of the Yellow River was not significantly contaminated by Cu, Pb, Zn, and Cd. Pb in Baiyin section may bring health risk to human being if it is used directly as drinking water. The accumulation of pollutants in fish tissues had caused oxidative stress and genetic material damage, but had not yet injured fish tissues. Heavy metals accumulated highly in liver and kidney of T. pappenheimi and G. hwanghensis. As a result, liver and kidney had potential value on monitoring metal pollution. T-AOC, MDA, DNA damage or MCN in tissues (liver, kidney, gill or peripheral blood) of T. pappenheimi were all useful bio-indicators in monitoring water pollution.更多还原