【作者】 杨丽华；

【导师】 方展强； 郑文彪；

【作者基本信息】 华南师范大学 ， 动物学， 2003， 硕士

【摘要】 本论文在调查广州市市售的经济水产品(食用鱼类和双壳类)重金属含量水平的基础上，确定广州地区几种污染较为严重的重金属即Cu、Zn、Cd和Cr。随后以这几种重金属作为实验毒物，以鲫鱼为实验动物，应用环境生物技术、火焰原子吸收分光光度法、邻苯三酚自氧化法、透射电镜等技术研究了重金属Cu、Zn、Cd和Cr对鲫鱼的急性毒性及其安全浓度评价、混合重金属在鲫鱼幼体组织内的积累和分布、Cd对鲫鱼鳃和肝脏中SOD活性的影响、Cd对鲫鱼肝细胞和肾细胞超微结构的影响等，全面和系统地研究了水环境中重金属暴露对鱼类的毒性影响，初步探讨了重金属污染对鱼类的个体——器官——组织——细胞——分子等各水平层次的影响，为制定渔业生产上预防性的管理措施提供科学依据，及时避免或减轻重金属污染对水生生态系统造成的损害。 以高氯酸—硝酸消化法和火焰原子吸收分光光度计测定了广州石牌市场食用鱼类和双壳贝类的Cd、Pb、Cr、Ni、Cu和Zn等重金属的含量。结果表明：双壳类对重金属积累的能力高于鱼类。鱼类不同组织器官对各种重金属积累能力明显不同，有毒重金属元素Cd、Pb、Cr和Ni主要分布于鳞片和鳃中，其食用部分中各重金属含量都远低于“海洋生物污染评价标准”和“人体卫生消费标准”，具安全的食用价值。但贝类的Cd含量已超过“人体卫生消费标准”，其中牡蛎的Cu和Zn含量则略超过“人体卫生消费标准”，其食用价值受到严重威胁，应引起重视。 采用静水法生物测试研究了重金属Cu、Zn、Cd和Cr对丰产鲫(Carassius auratus of Penze(♀)×Cyprinus acutidorsalis(♂))幼鱼的急性毒性，结果表明：Cu对鲫鱼为剧毒物质，Cd为中毒物质，Zn和Cr为低毒物质。四种重金属毒性大小顺序依次为：Cu＞Cd＞Zn＞Cr。Cu、Zn、Cd和Cr对鲫鱼的24h、48h、72h、96h的LC＿(50)分别为0.23、0.14、0.11、0.09mg／L，11.17、8.68、6.86、5.85mg／L，390.30、311.80、277.70、244.10mg／L，39.40、32.25、27.20、22.25mg／L，安全浓度分别为0.009mg／L、0.59mg／L、24.41mg／L、2.23mg／L。Cu对鲫鱼的安全浓度略低于渔业水域水质标准，Zn、Cd和Cr的安全浓度远远高于标准。 研究了安全浓度的混合重金属Cu、Zn、Cr、Cd污染在鲫鱼幼体组织中短期的积累和分布，实验结果表明：Cu、Zn、Cd和 Cr四种重金属之间的联合作用为毒性剧增的快同作用。Cd和 Cr在鲫鱼的鳃和肝脏中有极明显的积累（／0．01人在肌肉中的积累并不明显。除在曝露的12h和24h时观察到Zn在肝脏中有较明显的积累（／0．05）外，h和h在曝露期间在鱼体组织中无明显的积累。本研究首次发现 Cd、Cr和 Zn三种重金属在曝露初期，在肝脏的积累过程中，形成一个积累高峰，随后下降，推测可能与混合重金属间的相互作用有关，也可能与肝肋中MT的解毒功能有关。Cd在鲫鱼鳃和肝脏中属中度富集重金属，Cr在鲫鱼鳃和肝脏中属轻度富集重金属，而Zn在鲫鱼肝脏中属中度富集重余属。 使用浸浴法以0、0．73、1．46、2．95mg／L四个Cd离于质量浓度（分别为对照组浓度，96hLC。；；的 1／2、1／4和 1／8浓度）为丰产鲫幼鱼染毒六天，采用改良的邻苯三酚自氧化法分别测定了 12h，24h，48h、96h及 144h时鳃和肝脏组织中SOD的活性。结果表明，肝组织中的SOD酶活性和对Cd的敏感性均高于鳃，这与其执行的生理功能有关，肝脏是主要的解毒器官。鳃和肝脏中SOD酶活性的变化规律相似：低浓度组Cd曝露时，鲫鱼鳃和肝组织中SOD活性的变化在短时间内不明显，但随着处理时间的延长，Cd提高了鳃和肝组织中SOD活性，导致“毒物兴奋效应”。高浓度组Cd曝露时显著抑制了肝和鳃中的SOD活性，其作用随着曝露时间的延长和浓度的升高而增强，最高浓度组SOD活性一直显著低于对照组，实验木期，肝脏和鳃中的SOD活性达到最低水平，而后出现部分鲫鱼死亡，SOD酶活性降低所造成的活性氧伤害可能是引起鲫幼鱼死亡的重要原因。 利用透射电镜技术观察了Cd对鲫鱼肝细胞和肾细胞超微结构的影响，结果发现：Cd暴露对肝细胞的影响主要表现在部分肝细胞的细胞器死亡、解体，出现细胞空泡化，细胞问隙消失，粗面内质网片断化，线粒体结构破坏，溶酶体减少，出现脂褐素，脂滴数量减少等。对肾脏的影响主要表现为肾脏呈炎性反应，肾细胞刷状缘紊乱退化，粗面内质网增生，线粒体减少等。表明Cd暴露引起鲫鱼肝细胞和肾细胞的能量代谢及物质合成代谢等一系列正常的生理功能受到严重的影响。更多还原

【Abstract】 The main objective of this study is to investigate the biotoxic effect of heavy metals (cadmium (Cd), copper (Cu), zinc (Zn) and chromium (Cr)) in crucian (Carassius auratus of Penze + Cyprinus acutidorsalis . Using Cd, Cu, Zn and Cr as experimental toxicants and crucian as experimental creature, we employed the environmental biotechniques (flame atomic absorption spectrophotometry, the method of improved pyrogallol autoxidation and electron microscopy) to study the acute toxicity and secure concentrations of heavy metals to crucian; the accumulation and distribution of mixed heavy metals to fingling crucian; the activities of superoxide dismutase (SOD) of gill and liver tissues and the hispathological and ultrastructural change of superfine structure of liver and kidney of crucian after cadmium exposure. Through which, we intended to fully and systemically study the toxic influence of heavy metals to fish, and preliminarily discuss the influence of heavy metals pollution to the diversified level of fish such as individual, organ, tissue, cell and molecule. Thus we tried to provide scientific evidence to establish preventative management measures, avoid and relieve the harm of heavy metals pollution to aquicolous ecosystem in time.Six species of edible fishes and six species of edible bivalves were purchased from Shipai market in Guangzhou. The flesh of this biota was tested for their cadmium, lead, chromium, nickel, copper, and zinc concentrations (based on wet weight) using the method of HNQ3-HC104 Digestion and Flame Atomic Absorption Spectrophotometry. The results showed that the abilities of bioaccumulation of bivalves were stronger than those of fish. The concentrations of heavy metals in different tissues in fish were significant different (p<0. 01). Poisonous metals such as Cd, Pb, Cr and Ni were mainly distributed in scale and gill. Forfishes, the content of heavy metals in the edible part were far below Pollution Evaluation Standards for Marine Organism and Healthy Standards for Human Consumption, which was safe to be eaten. Cd content of bivalves had exceeded Healthy Standards for Human Consumption, and the contents of Cu and Zn in oyster had also slightly exceeded Healthy Standards for Human Consumption. Their edible value had been affected, which should be recognized.The acute toxicity of Cu, Zn, Cd and Cr to crucian ( Carassius auratus of Penze Cyprinus acutidorsalis was studied with the static test method. The results showed that Cu to crucian was a drastic toxicant; cadmium was median toxic; zinc and Cr were low toxic. The toxicity sequence of four heavy metals to crucian was Cu>Cd>Zn>Cr. The LC50 of 24h, 48h, 72h and 96h for Cu to crucian were 0.23, 0. 14,0. 11 and 0. 09mg/L. Those for Zn were 11. 17, 8. 68, 6. 86 and 5. 85mg/L. For Cd and Cr there were 390.30, 311.80, 277.70 and 244. 10mg/L, 39.40, 32. 25, 27.20 and 22. 25mg/L. The safe concentrations of these metals were 0. 009mg/L> 0. 59 mg/L, 24. 41 mg/L and 2.23 mg/L respectively. The safe concentration of Cu to crucian was slightly lower than Standard of Fishery Water Quality. The safe concentrations of Zn, Cd and Cr to crucian were far exceeded the standard.The short-term accumulation and distribution in young crucian tissue of mixed secure concentrations of heavy metals Cu, Zn, Cr and Cd pollution was studied. The results showed that associated interaction of the four heavy metals was synergistic effect of accumulated toxic. The accumulation of Cd and Cr was evident in gills and livers (p <0. 01) and wasn’ t evident in muscles. Zinc accumulation was evident in livers at 12h and 24h after exposure (P<O.05), however, Cu accumulation wasn’ t evident in fish tissues in the exposure time. The results also indicated that, in the beginning of the exposure time, Cd, Cr and Zn had an accumulation peak in liver and then a decrease in accumulationconcentration, which maybe associated with the interaction of mixed heavy metals or the detoxifcation of metallothionein (MT) in the livers. In gills and livers Cd to crucian更多还原