三种酰胺类除草剂在水藻体系中的降解及脱毒研究

【作者】 席萌；

【导师】 刘维屏；

【作者基本信息】 浙江大学 ， 环境科学， 2006， 硕士

【摘要】 本文以三种常见的酰胺类除草剂Rac-异丙甲草胺(Rac-metolachlor)、S-异丙甲草胺(S-metolachlor)、丁草胺(butachlor)为对象,研究了它们对普通小球藻(chlorella vulgaris)、蛋白核小球藻(Chlorella pyrenoidosa)、斜生栅藻(Scendesmus obliquus)三种水藻体系的毒性效应,结果显示除草剂对普通小球藻、蛋白核小球藻、栅藻均有很强的生长抑制现象。初步的毒理学试验表明,硫代硫酸钠(STS)能够减弱酰胺类除草剂对藻类的急性毒性,STS对酰胺类除草剂的转化作用使其有可能作为一种良好的化学修复剂用于减轻环境和健康风险。 研究表明,S-异丙甲草胺对三种藻的毒性效应大于 Rac-异丙甲草胺和丁草胺;Rac-异丙甲草胺、S-异丙甲草胺和丁草胺在低浓度时刺激了藻类的生长;除草剂对藻类的影响在很大程度上表现为浓度相关性,除草剂浓度越高,藻类生长受抑制的程度越大。 STS能够降低Rac-异丙甲草胺、S-异丙甲草胺和丁草胺的毒性,促进藻类生长。当处理的丁草胺和Rac-异丙甲草胺浓度小于其96h-EC50值时,加入STS能较好的恢复蛋白核小球藻的生长;而当处理的除草剂浓度大于其96h-EC50值,加入STS没有效果。 25mg/L和10mg/L的STS减弱了Rac-异丙甲草胺和S-异丙甲草胺的对蛋白核小球藻的毒性效应;经STS预处理24h的S-异丙甲草胺的浓度组,蛋白核小球藻的衰亡比之未经预处理的组推迟了24h;比较Rac-异丙甲草胺和S-异丙甲草胺加入STS预处理24h毒性效应的变化,发现STS与Rac-异丙甲草胺预反应24h后接种蛋白核小球藻,修复作用不明显,而STS与S-异丙甲草胺预反应24h后接种蛋白核小球藻,96h以前表现出了良好的修复效果。更多还原

【Abstract】 The toxicity of Rac-metolachlor S-metolachlor and butachlor on three algae was carried out. The results showed that these herbicides had inhibition action of different degrees on algae of chlorella vulgaris, Chlorella pyrenoidosa and Scendesmus obliquus. Preliminary toxicity assays using algae showed that sodium thiosulfate transformation largely eliminated the acute toxicity of Acetanilide herbicide to this organism. These results suggested that sodium thiosulfate transformation of Acetanilide herbicide was a benign chemical approach that may be used for mitigating environmental and health risks.Results showed that S-metolachlor was more toxic than Rac-metolachlor and butachlor of algae. When the herbicides were presented in low concentrations, growth of algae was stimulated. The growth of algae were closely relative to the concentration of herbicides, results showed that the inhibition of algae was stronger with hebicides in higher concentration.Sodium thiosulfate could eliminate the toxicity of Rac-metolachlor, S-metolachlor and butachlor to promote the growth of chlorella vulgaris, Chlorella pyrenoidosa and Scendesmus obliquus. When herbicides were below 96h-EC50, the Chlorella pyrenoidosa grew well with Sodium thiosulfate, while herbicides were above 96h-EC50, the Sodium thiosulfate was not effective.Preliminary toxicity assays using Chlorella pyrenoidosa showed that Sodium thiosulfate transformation largely eliminated the acute toxicity of Rac-metolachlor and S-metolachlor to this organism. The study showed that 24 hours’ pre-reaction of Sodium thiosulfate and S-metolachlor, the effect of inhibiting growth of Chlorella pyrenoidosa delayed. Results showed that 24 hours’ reaction of Sodium thiosulfate and S-metolachlor could remediate the growth of Chlorella pyrenoidosa in 96 hours, however, the reaction of Sodium thiosulfate and Rac-metolachlor showed not effect.更多还原