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A Study On Acute Toxicity Of Some Substituted Benzenes To Photobacterium Phosphoreum

Posted on:2004-01-02Degree:MasterType:Thesis
Country:ChinaCandidate:L H DiFull Text:PDF
GTID:2121360095450199Subject:Geotechnical engineering
Abstract/Summary:PDF Full Text Request
Nowadays it is one of the difficult problems that how to evaluate the toxicity of the substituted benzenes to the environment efficiently. Photobacterium Phosphoreum used as bio-indicator is convenience sensitive and economical. 17 substituted benzenes were studied in this paper. The acute toxicity of these 17 tested compounds and the combined toxicity of 5 compounds were measured. The data of single compounds was discussed roughly and the predicted equation was set up. The effect of combined compounds was analysed approximately. The toxicity of two kinds of wastewaters to Photobacterium Phosphoreum was measured at last. The results can be used to evaluate the toxicity impact to the environment of the treatment technics of these wastewaters.The acute toxicities of 17 substituted benzenes to Photobacterium Phosphoreum were measured, and the effects of substituted groups and positions on toxicities were discussed roughly. The molecular structural descriptors, such as quantum chemical parameters and linear solvation energy parameters, with clear physicochemical senses, were calculated, and relationships between toxicities of tested compounds and their molecular structural descriptors were developed by using quantitative structure-activity relationship (QSAR) technique. The results indicated that there was a significant positive proportion between toxicity and intrinsic volume or area of compound molecules, and the equations were robust enough through Jacknife test. The results were satisfying when the obtained equation was used to predict 27 compounds with similar structure as selected ones.Based on the determination of single compounds, Benzene Phenol Aniline Nitrobenzene and o-chlorophenol were selected. These 5 compounds were combined by equal toxicity method and the toxicity types were evaluated. Then another 5 groups were choosed. These compounds were combined by varied proportion. And the combined toxicity effect were also determined. The law of the combined toxicity and the influence factor were analyzed roughtly. The results indicated that the combined toxicity was related not to the types but to the contents of the test compounds.The toxicity of wastewater to the environment was not well eliminated by most treatment plants. The paper wastewater was difficult to be treated for high COD and toxiccompounds. The sewage was also not think much of. In the last part, the toxicity of paper intermediate wastewater and sewage from different treatments were measured. For paper wastewater, the results indicated that wastewater was still provided with toxicity even after coagulation although the composite coagulation reagent was the best one to get rid of the toxicity of wastewater . On the other hand, its toxicity could be greatly dropped by ultrafiltration and MWC06000 was the best one. For the sewage from a wastewater treatment plant, the existing technics could remove part toxicity, but there was some toxicity left in the effluent So the control of the toxicity impact of the treatment technics was very important.
Keywords/Search Tags:substituted benzenes, Photobacterium Phosphoreum, acute toxicity, combined toxicity, quantitative structure activity relationships, toxicity enhance index
PDF Full Text Request
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