The genotoxieity of drinking water treated with 6 disinfection methods and the effects of disinfection conditions were investigated using the urea-test The pretreatment procedure of samples for the urea-test was optim...The genotoxieity of drinking water treated with 6 disinfection methods and the effects of disinfection conditions were investigated using the urea-test The pretreatment procedure of samples for the urea-test was optimized for drinking water analysis. The results of the urea-test were in good correlation with those of the Ames-test The genotoxicity and production of haloacetic acids （HAAs） were the highest for chlorinated samples. UV ＋ chloramination is the safest disinfection method from the aspects of genotoxicity, HAA production and inactivation effects. For chloramination, the effects of the mass ratio of C12 to N of chloramine on genotoxicity were also studied. The changes of genotoxicity were different from those of HAA production, which implied that HAA production cannot represent the genotoxic potential of water. The genotoxicity per chlorine decay of chlorination and chloramination had similar trends, indicating that the reaction of organic matters and chlorine made a great contribution to the genotoxicity. The results of this study are of engineering significance for optimizing the operation of waterworks.展开更多
Flow cytometry （FCM） has been widely used in multi-parametric assessment of cells in various research fields, especially in environmental sciences. This study detected the metabolic activity of Escherichia coli and ...Flow cytometry （FCM） has been widely used in multi-parametric assessment of cells in various research fields, especially in environmental sciences. This study detected the metabolic activity of Escherichia coli and Staphylococcus aureus by using an FCM method based on 5-cyano-2,3-ditolyltetrazolium chloride （CTC）; the accuracy of this method was enhanced by adding SYTO 9 and 10% R2A broth. The disinfection effects of chlorine, chloramine, and UV were subsequently evaluated by FCM methods. Chlorine demonstrated stronger and faster destructive effects on cytomembrane than chloramine, and nucleic acids decomposed afterwards. The metabolic activity of the bacteria persisted after the cytomembmnewas damaged as detected using CTC. Low-pressure （LP） UV or medium-oressure （MP） UV treatments exerted no significant effects on membrane permeability. The metabolic activityof the bacteria decreased with increasing UV dosage, and MP-UV was a stronger inhibitor of metabolic activity than LP-UV. Furthermore, the membrane of Gram-positive S. aureus was more resistant to chlorine/chloramine than that of Gram-negative E. coil In addition, S. aureus showed higher resistance to UV irradiation than E. coli.展开更多
基金supported by the National Nature Science Foundation of China(No.50778096)
文摘The genotoxieity of drinking water treated with 6 disinfection methods and the effects of disinfection conditions were investigated using the urea-test The pretreatment procedure of samples for the urea-test was optimized for drinking water analysis. The results of the urea-test were in good correlation with those of the Ames-test The genotoxicity and production of haloacetic acids （HAAs） were the highest for chlorinated samples. UV ＋ chloramination is the safest disinfection method from the aspects of genotoxicity, HAA production and inactivation effects. For chloramination, the effects of the mass ratio of C12 to N of chloramine on genotoxicity were also studied. The changes of genotoxicity were different from those of HAA production, which implied that HAA production cannot represent the genotoxic potential of water. The genotoxicity per chlorine decay of chlorination and chloramination had similar trends, indicating that the reaction of organic matters and chlorine made a great contribution to the genotoxicity. The results of this study are of engineering significance for optimizing the operation of waterworks.
文摘Flow cytometry （FCM） has been widely used in multi-parametric assessment of cells in various research fields, especially in environmental sciences. This study detected the metabolic activity of Escherichia coli and Staphylococcus aureus by using an FCM method based on 5-cyano-2,3-ditolyltetrazolium chloride （CTC）; the accuracy of this method was enhanced by adding SYTO 9 and 10% R2A broth. The disinfection effects of chlorine, chloramine, and UV were subsequently evaluated by FCM methods. Chlorine demonstrated stronger and faster destructive effects on cytomembrane than chloramine, and nucleic acids decomposed afterwards. The metabolic activity of the bacteria persisted after the cytomembmnewas damaged as detected using CTC. Low-pressure （LP） UV or medium-oressure （MP） UV treatments exerted no significant effects on membrane permeability. The metabolic activityof the bacteria decreased with increasing UV dosage, and MP-UV was a stronger inhibitor of metabolic activity than LP-UV. Furthermore, the membrane of Gram-positive S. aureus was more resistant to chlorine/chloramine than that of Gram-negative E. coil In addition, S. aureus showed higher resistance to UV irradiation than E. coli.
