【作者】 李志斐；

【导师】 谢骏；

【作者基本信息】 上海海洋大学 ， 水产养殖学， 2011， 硕士

【摘要】 三甲基氯化锡（Trimethyltin chloride,TMT）是一种重要的有机锡化合物,广泛应用于工业塑料热稳定剂、木材防腐剂、防腐涂料、农药和杀螺贝剂等方面,也曾用于化学消毒剂和杀菌灭虫剂,与工农业生产关系密切。特别是随着工业有机锡塑料及二手塑料再加工的迅速发展,TMT随生产废水、地表径流等途径进入水环境中,已在海洋、江河、水库、地下水、水生生物机体内等广泛存在。TMT具有较强的亲水性和亲脂性,极易通过消化和皮肤黏膜进入机体,对水生生物产生毒性并在体内富集,因此极有可能对水生生物造成潜在危害。然而目前对TMT的水生态毒性研究较少,正确了解TMT的水生生物毒性毒理效应及其对水生态系统的影响,为环境安全评价提供科学依据,研究结果具有现实意义。本研究选取水生态系统中的浮游植物、浮游动物和鱼类三个营养级上的代表生物,即蛋白核小球藻、大型溞和斑马鱼为试验生物，采用急性毒性试验方法，研究TMT对水生生物的毒性效应。结果如下:1.TMT对蛋白核小球藻的生长具有一定的抑制作用,并呈现出明显的剂量-效应相关关系。在整个生长试验过程中,0.1、0.38和1.14 mg/L处理下蛋白核小球藻虽然生长受到抑制但仍然在缓慢生长;5.31和20 mg/L处理细胞数目没有增长,表现为很强的抑制作用,从试验开始蛋白核小球藻生长就下降直至实验液逐渐透明,镜下观察藻细胞分解,大量藻细胞死亡。TMT浓度与叶绿素a含量表现出一定的剂量-效应关系,且随药物浓度的增大,藻体内叶绿素a含量增长速度减慢,其变化趋势与藻细胞密度的变化趋势基本吻合。TMT对蛋白核小球藻的96 h-EC₅₀为0.46 mg/L,属于极高毒物质。2.随着试验时间的延长和TMT浓度的增加,大型溞的死亡率和抑制率逐渐增加。TMT浓度为0.05 mg/L时,48 h对大型溞活动产生部分抑制，但无死亡现象;TMT浓度为0.185 mg/L时,24 h大型溞的死亡率为60%,抑制率为80%,48h大型溞的死亡率已升到100%。TMT对大型溞的24 h和48 h半数影响浓度LC₅₀分别为:0.15和0.087 mg/L,TMT对大型溞的毒性属极高毒性。3.TMT对斑马鱼的96 h-LC₅₀值为2.35 mg/L,TMT对斑马鱼的毒性属高毒。TMT对斑马鱼鳃Na⁺,K⁺-ATPase有明显的抑制作用:当TMT浓度≥0.78 mg/L时,酶活性被完全抑制,抑制率>32%;当TMT浓度为0.39 mg/L时,酶活性先表现为抑制,24 h后有恢复到对照组水平的趋势。TMT对斑马鱼头部AchE活性表现为抑制,暴露时间内随着时间的延长和药物浓度的增加,酶活性抑制增强,由于鱼脑AchE的高波动性,试验中只有最高浓度（1.17 mg/L）组受到明显的抑制（p<0.05）。TMT对斑马鱼肌肉SOD活性总体表现为先激活后下降趋势,TMT浓度越高酶活性激活越快,下降也越快,其中0.39、0.78和1.17 mg/L组活性分别在48 h、24 h和12 h激活达到最大,分别为对照组的153%、145%和153%。以上结果表明,TMT对斑马鱼属于高毒。斑马鱼鳃Na⁺,K⁺-ATPase是三甲基氯化锡的作用标靶,可以作为TMT对斑马鱼毒性效应的敏感指标。4.TMT对斑马鱼胚胎发育有较强的毒性效应,可导致胚胎孵化率显著下降,畸形率和死亡率显著升高,TMT浓度≥0.5 mg/L,96 h的孵化率﹤50%,畸形率>35%,死亡率>25%。表明TMT对鱼类发育存在威胁。5.根据TMT对藻类、溞类和鱼类的急性毒性实验结果(EC₅₀和LC₅₀),在评价因子为1000的条件下,采用商值法对TMT的生态影响进行风险评价,得出0.087μg/L作为TMT对水生生物的无影响浓度。更多还原

【Abstract】 Trimethyltin chloride （TMT） is an important organictin compound. It is widely used as plastic stabilizers, wood preservatives, anti-corrosion coatings, pesticides, and kill snails, as well as applied by chemical disinfector and sterilization, which is closely related to industry and agriculture. TMT could be released to environment following the factory effluent and surface runoff. With the rapidly development of organictin plastic and plastics reprocessing, TMT existed widely in the ocean, river, reservoir, groundwater and aquatic organism. Because of the TMT having both hydrophilic and lipophilic, it could enter organism through digestion and skin easily, generate toxicity to aquatic organisms and be accumulated in the body. However, the effects of TMT on ecological toxicity of aquatic organisms are still not clear. The present study is to determine the toxicity of TMT to aquatic organisms and ecosystem and evaluated the environmental safety. Chlorella pyrenoidosa, Daphnia magna, Danio rerio are the typical organisms of plankton, zooplankton and fish in the aquatic ecosystem. The toxicity effects of TMT on Chlorella pyrenoidosa, Daphnia magna, Danio rerio were studied in this research. Moreover, the effects of TMT on physio-biochemical characteristics of Danio rerio were conducted in this present study. The main results were listed as following:1. The growth of Chlorella pyrenoidosa was inhibited by TMT, and showed a significantly dose-response relationships. During the experiment, the growth of Chlorella pyrenoidosa in 0.1, 0.38, and 1.14 mg/L was inhibited to some extent, but still had a slowly growth trend; in 5.31 mg/L, the growth was completely inhibited. In 20 mg/L, the growth had a strong inhibition, the algae cells became transparent gradually from the beginning of the experiment on, in which most of them were disintegrated under the microscope and lethal. The TMT concentration and chlorophyll a content had a dose-response relationship, and the chlorophyll a content decreased slowly with the increase of TMT concentration. The algae cell density showed similar tendency. TMT had the highest toxicity for Chlorela pyrenoidosa, the 96 h-LC₅₀ concentration was 2.45 mg/L.2. The inhibition rate and mortality of Daphnia magna increased with the increase of TMT concentration and the test time. When the concentration of TMT was 0.05 mg/L, Daphnia magna activities were partly suppressed at 48h, but no dead; while the concentration of TMT was 0.185 mg/L, the mortality and inhibition rate was 60% and 80% respectively, and up to 100% at 48 h. The 24 h-LC₅₀ and 48 h-LC₅₀ concentration was 0.15 and 0.087 mg/L, respectively. TMT had the highest toxicity to Daphnia magna.3. TMT was high-toxic to Danio rerio, and the 96 h-LC₅₀ was 2.35 mg/L. The activities of Na⁺,K⁺-ATPase in gill was inhibited significantly by TMT. When the concentration≥0.78 mg/L, the Na⁺,K⁺-ATPase activity was inhibited significantly, and the inhibition rate≥32%. The activities of the low concentration group （0.39 mg/L） was inhibited first and then recovered after 24 h. With the increase of TMT concentration and exposure time, the inhibition of AchE activity in head was increased . Due to the high instability, only the highest concentration group was inhibited significantly. The SOD activity in muscle of Danio rerio showed the trend of increasing at first, and then decreased. When the concentration of TMT was higher, the SOD activity was decreased and activated fasterly. The SOD activity of 0.39, 0.78 and 1.17 mg/L group activated to the maximum level at 48 h, 24 h and 12 h, the activation rate was 153%, 145% and 153% of control, respectively. The above results showed that TMT was high-toxic to Danio rerio, the gill Na⁺,K⁺-ATPase and muscle SOD are targets of TMT.4. The Danio rerio embryos were significantly affectted by TMT. The hatching decreased significantly, but the deformity and mortality increased obviously. When the concentration of TMT≥0.5 mg/L, the hatching rate at 96 h was less than 50%, the deformity and mortality were≥35% and 25%, respectively. It showed that TMT could obviously inhibit the embryo development of Danio rerio.5. According to the acute toxicity test results(EC₅₀ and LC₅₀) of TMT on algae, daphnia and fish, when the evaluation factor was 1000, the quotient method was adopted to assess the ecological risk of TMT, which obtained that the concentration value 0.087μg/L of TMT was no-effect concentration to aquatic organisms.更多还原