【作者】 吴东艳；

【导师】 周立志；

【作者基本信息】 安徽大学 ， 生态学， 2011， 硕士

【摘要】 近年湖泊污染受到广泛关注,特别是长江中下游富营养化湖泊形成的蓝藻“水华”已经成为严重的环境问题,影响到区域生态安全,湖泊富营养化成为了制约经济和社会持续性发展的重要因素。巢湖是我国长江流域严重富营养化的淡水湖泊之一；菜子湖相对受工业污染较轻,湖泊富营养化较不明显。水质的恶化必然会影响到生活在其中的水生生物,依赖于湖泊生活的人们身体健康也会受到威胁,因此控制水体污染非常重要。准确评估水体污染程度,是治理和改善湖泊富营养化的前提。水体污染对水生动物产生的毒性效应,能直接反映水体的污染程度。因此利用水生动物监测水体污染,有助于准确评估水体污染潜在的生态风险。本研究以安徽沿江富营养化程度不同的两个浅水湖泊巢湖和菜子湖为研究区域,选择克氏原螯虾(Procambarus clarkii)为指示物种,评价了这两个湖泊水体污染物的毒性作用。利用微核实验和彗星电泳实验对克氏原螯虾血细胞的DNA损伤和微核率进行了检测,分析了克氏原螯虾的遗传毒性效应及其季节变化特征,探讨了水体富营养化和水生动物遗传毒性之间的相关性,评价了两湖泊水体的综合污染状况,研究结果如下：(1)巢湖克氏原螯虾血细胞微核率4月份最低,为0.316±0.131,11月份最高0.691±0.057；菜子湖克氏原螯虾血细胞微核率4月份为0.243±0.063,11月份为0.394±0.017；DNA损伤4月份两湖泊最低,巢湖TailDNA、TM和OTM值分别为2.34±0.88、0.36±0.22和0.52±0.20,菜子湖TailDNA、TM和OTM值分别为1.92±1.98、0.35±0.33和0.51±0.27,11月份最高,巢湖TailDNA、TM和OTM值为8.92±1.73、3.94±0.17和4.63±1.62,菜子湖TailDNA、TM和OTM值为6.17±0.20、1.54±0.03和1.63±0.13,4-11月份巢湖和菜子湖克氏原螯虾血细胞微核率和DNA损伤都随着时间的推移增加,说明2010年4-11月份巢湖和菜子湖克氏原螯虾遗传毒性随时间的变化增强,两湖泊存在不同程度遗传毒性污染物的污染。(2)富营养化程度较高的巢湖克氏原螯虾的遗传毒性高于菜子湖,两湖泊7、8、9、10和11月份细胞微核率差异性均达到极显著水平(P<0.01),DNA损伤6月份差异显著(0.01<P<0.05),7、8、9、10和11月份差异性达到极显著(P<0.01),巢湖水体对克氏原螯虾具有更强的遗传毒性,巢湖含有更高浓度的具有遗传毒性的污染物。(3)巢湖蓝藻爆发初期6、7月份DNA损伤和微核率都有较大的增加幅度,表明克氏原螯虾遗传毒性有增加趋势,DNA损伤5月和6月,6月和7月差异性达到极显著(P<0.01),微核率6-7月份差异性显著(0.01<P<0.05),6、7月份巢湖克氏原螯虾遗传毒性增加幅度最大；但是菜子湖克氏原螯虾遗传毒性没有相同的变化趋势,所以,我们蓝藻爆发初期巢湖克氏原螯虾遗传毒性增加可能与水体富营养化引起的蓝藻水华有关。(4)两种不同的检测方法结果一致,但彗星实验相对更敏感,所以有必要从多方面考虑,将不同遗传毒性检测方法结合起来,才能更好的监测污染物对机体产生的遗传毒性作用。富营养化严重的巢湖克氏原螯虾遗传毒性具有明显的季节特征,因此对蓝藻水华期水质遗传毒性应予以高度的关注和重视。更多还原

【Abstract】 Lake pollution received extensive attention in recent years. Particularlly, eutrophication resulting in cyanobacteria bloom in the lakes in the middle and lower Yangtze River floodplain has become a serious environmental problem, threating the security of regional ecological systems. The lake eutrophication, becoming a major factor hampering economic and social sustainable development, is a serious national environmental problem. The Chaohu Lake is one of the most serious eutrophication lakes in China. Caizi Lake is less affected by industrial pollution relatively, and had less eutrophication. Inevitably, organisms are affected adversely, and the residents relying on the lakes 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. So, using organisms to monitor water pollution would supplement the routine water monitoring.In this study, Chaohu Lake and Caizi Lake two different eutrophic lakes along the Yangtze River in Anhui Province were chosed as our study area, and Procambarus clarkii as target species to assess the toxic effects of the pollutants in the two lakes. DNA damages and micronucleus ratios of haemocytes of Procambarus clarkii detected by comet assay and micronucleus test, seasonal variation of genotoxicity and the correlation between water eutrophic and genotoxicity were analyzed to evaluate the pollution of the two lakes. The results were as follows.(1) In Chaohu Lake and Caizi Lake, the lowest micronucleus ratios of haemocytes of Procambarus clarkii in April were 0.316±0.131 and 0.243±0.063 respectively, and the highest values in November were 0.691±0.057 and 0.394±0.017 respectively. The lowest values of the three indicators of DNA damage, JailDNA，TM and OTM were 2.34±0.88,0.36±0.22 and 0.52±0.20 respectively in Chaohu Lake, and 1.92±1.98,0.35±0.33 and 0.51±0.27 respectively in Caizi Lake. The highest values were 8.92±1.73,3.94±0.17,4.63±1.62 in Chaohu Lake, and 6.17±0.20, 1.54±0.03, 1.63±0.13 in Caizi Lake respectively. The highest values of micronucleus ratios and DNA damage appeared in November and the lowest values appeared in April. Micronucleus ratios and DNA damage had an increasing tendency frome April to November in the two lakes, indicating that the genotoxicity enhanced as the time changed and there were different pollution in the two lakes(2) The higher eutrophic Chaohu Lake was detected to have higher genotoxicity than the lower eutrophic Caizi Lake. Micronucleus ratios and DNA damage reached significant differences (P< 0.01) from July to November between the two lakes. In June, DNA damage reached differences (0.01< P< 0.05) between the two lakes. There has the higher genotoxicity on Procambarus clarkii and it contains the higher concentration of genetic toxic pollutants in Chaohu Lake.(3) In the early period of cyanobacterial bloom June and July, DNA damage and micronucleus ratios increased significantly in Chaohu Lake, which indicates increased genotoxicity to Procambarus clarki. DNA damage reached significant differences (P<0.01) between May and June, June and July, and micronucleus ratios reached differences (0.01<P<0.05) between June and July. In June and July, the genetic toxicity of Procambarus clarkii increased greatest in Chaohu Lake. But there did not have the similar tendency in Caizi Lake. So, we thought that genotoxicity significantly increased in the early period of cyanobacterial bloom maybe related with Chaohu Lake eutrophic.(4) Detection results were the same for the two different tests, but comet assay is more sensitive then micronucleus test. So we suggest that it’s necessary to combine the two tests to get more effective detection of genetic toxicity.Genetic toxicity of Chaohu Lake has obvious seasonal characteristics, so it is suggested to pay more attention on the water quality during the period of cyanobacterial bloom.更多还原