Three Amides Herbicide Degradation In The Algae System And Detoxification Research

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.