umu试验研究饮用水氯和氯胺消毒过程中遗传毒性的变化以及消毒条件的影响

Genotoxicity of Drinking Water During Chlorine and Chloramine Disinfection and the Influence of Disinfection Conditions Using the umu-test

采用umu遗传毒性测试方法考察了消毒剂投加量、反应时间和消毒剂氯氮比对某饮用水厂臭氧-生物活性炭出水加氯或氯胺消毒前后遗传毒性的影响.结果表明,炭后水具有一定的遗传毒性(20～70 ng/L),加氯或氯胺消毒后遗传毒性增加.反应时间为24 h,在相同投加量下氯消毒遗传毒性(40～95 ng/L)高于氯胺消毒遗传毒性(20～40 ng/L);当氯初始投加量从0 mg/L增加到10 mg/L时,炭后水的遗传毒性先迅速增加,在0.5～1 mg左右达到极大值,然后再降低,在3～5 mg左右达到极小值后缓慢上升,但是氯胺消毒后水样遗传毒性变化规律不如氯消毒的明显.当投加量为3 mg/L时,随着反应时间从0 h延长至72 h,无论是氯消毒还是氯胺消毒,炭后水遗传毒性均是先迅速增加,在2 h时达到极大值后再下降,在18 h左右达到极小值然后缓慢上升,而且任意反应时间内,氯胺消毒的遗传毒性(20～62 ng/L)均小于氯消毒(83～120 ng/L).本试验还研究了消毒剂氯氮比对炭后水氯消毒后遗传毒性的影响.在本试验条件下,从遗传毒性的角度看,对于饮用水消毒氯胺比氯更安全,而且2种消毒方式的遗传毒性的变化规律均不同于总HAAs的变化规律.

In this study,the effects of disinfectant dosage,reaction time and the ratio of Cl2 to N of disinfectant on genotoxicity of effluent of ozone-biological activated carbon（O3-BAC） during chlorine or chloramine disinfection were investigated using umu-test.It was found that,the genotoxicity of effluent of O3-BAC before disinfection ranged from 20-70 ng/L,and it increased after disinfection by chlorine or chloramines.With the same reaction time（24 h）,genotoxicity after chlorination（40-95 ng/L） was higher than that after chloramination（20-40 ng/L）under same initial dosage.For chlorination,with initial dosage increasing from 0 mg/L to 10 mg/L,genotoxicity increased firstly,and got the maximum value at about 0.5-1 mg/L dosage,then decreased and got the minimum value at about 3-5 mg/L dosage,and finally increased again.For chloramination,genotoxicity didn＇t change that much.With the dosage of 3 mg/L and reaction time increasing from 0 h to 72 h,no matter for chlorine or chloramines disinfec.tion,genotoxicity of effluent of O3-BAC both increased firstly,and got the maximum value at about 2 h,then decreased and got the minimum value at about 18 h,and finally increased again,and genotoxicity after chlorine disinfection（83-120 ng/L）was higher than that after chloramines disinfection（20-62 ng/L）under same reaction time.Further more,effects of the different ratios of Cl2 to N of disinfectant on genotoxicity of effluent of O3-BAC were also studied.Results of this study demonstrate that under test conditions,chloramine disinfection is safer than chlorine disinfection in the aspect of genotoxicity for drinking water,and the changes of genotoxicity are different from those of total HAAs.