Detection,Formation And Occurrence Of New Polar Phenolic Disinfection Byproducts In Drinking Water

New polar phenolic disinfection byproducts(DBPs)possess significantly developmental toxicity and growth inhibition than commonly known aliphatic DBPs,and they can act as intermediate DBPs(produced by reactions between HOCl and precursors)to form the U.S.EPA regulated DBPs(e.g.thrihalomethanes and haloacetic acids),hence they have been increasingly attracting people’s concern.In this study,based on ultra performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry(UPLC/ESI-tqMS)IntellistartTM,AntoDwell,and single factor experiment analyse,the instrumental parameters(column temperature,column type,mobile phase,ion source temperature,desolvation gas temperature,desolvation gas flow rate,cone gas flow rate,dwell time,cone voltage and collision energy)of identification method of 13 DBPs were optimized.In addition,the impact of disinfection contact times(1,6,12,24 and 72 h),disinfectants(chlorine and chloramines)and pH values(6.0,7.0,7.5,8.0 and 9.0)on the 13 DBPs were investigated,also precursor compound was identified and the formation mechanism was discussed by using UPLC/ESI-tqMS multiple reaction monitoring scan and precursor ion scanning technique.At last,the concentration and occurrence of 13 new DBPs were investigated in 16 drinking water plants of East China.The conclusions of this study are as follows:(1)The instrumental detection and quantitation limits were substantially lowered to 0.42-6.44 and 1.35-16.51 μg/L from 2.87-23.75 and 6.24-45.12μg/L after optimization,respectively.(2)Within a contact time of 3 d,the total concentration of the 13 DBPs formed in chlorination were much higher than those formed in chloramination.In chlorination,each of the 13 DBPs formed quickly and decomposed rapidly,but their total concentration showed a decreasing trend with contact time.In chloramination,as contact time increased,the concentration of four trihalophenols firstly increased and then decreased,whereas the concentration of the other nine DBPs showed an increasing trend with contact time.In chlorination and chloramination,by increasing the pH from 6.0 to 9.0,the formation of the 13 DBPs decreased by 57.8%and 62.3%,respectively.Gallic acid was found to be present in real source water samples and a simulated source water sample,and could generate 13 DBPs after chlorination and chloramination.(3)12 of the 13 DBPs(except for 3-bromo-5-chloro-4-hydroxybenzoic acid)were identified and quantified in 16 tap water samples collected from eight major cities in East China,and the total concentrations of 13 DBPs were from 9.5 to 329.8 ng/L.The higher concentrations of the 13 DBPs in tap waters might result from the higher bromide levels in source waters.Compared to conventional disinfection technologies,ozone-activated carbon treatment prior to disinfection might effectively inhibit the formation of the 13 DBPs in tap water based on the reduction of precursors.Compared with the chlorination,chloramination can reduce the total concentration of the 13 DBPs in drinking waters.Results of this research can provid technical supports for detection and accurate quantification of the 13 DBPs in micro polluted drinking water,research approachs and theoretical foundation for the control of DBPs pollution in drinking water,the results of occurrence of 13 new DBPs in drinking waters provide references for the establishment of management policies in relevant areas.