The Detection And Formation Potential Of New Type Haloquinone Disinfection By-products In Drinking Water

Water is the important strategic resource for our social and economic development,and drinking water safety has been the focus of society attention.Halobenzoquinones(HBQs)are emerging disinfection by-products(DBPs)in drinking water,which are more toxic than those regulated DBPs and may cause bladder cancer.To determine the HBQs in drinking water,an analytical method using solid phase extraction(SPE)combined with liquid-phase mass spectrometry technology was established.The occurrence of HBQs in drinking water of Wuhan was investigated,and the information potential was studied through precursor identification and disinfection simulation.The main results are as follows:1.The extraction effeciencies of three different types of SPE columns Bond Elut C18,Bond Elut ENV and Oasis HLB were compared,and the results showed that the Bond Elut ENV column was better than the others.The elution conditions,including the choice of the elution solvent and corresponding volume,were also investigated.In addition,the analytical method performances were evaluted: The limitation of detection was 14-450 ng/L,and the standard relative deviation(c=10 ?g/L,50 ?g/L,n=6)was 1.90-14.50%,and the recovery was in the range of 65.12~116.92% except 2,5-dibromo-1,4-benzoquinone,2,3,5,6-tetrabromo-1,4-benzoquinone and 2,6-DIBQ with values below 50%.There are 8 HBQs detected in the output water of five waterworks in Wuhan,including five Cl-HBQs: 2,6-dichloro-1,4-benzoquinone,3,4,5,6-tetrachloro-1,2-benzoquinone,2,3,5,6-Tetrachloro-1,4-benzoquinone,2,5-dichloro-1,4-benzoquinone and 2,3,5-Trichloro-1,4-benzoquinone,with an average concentration range of 1.00-42.14 ng/L,and three Br-HBQs: 2,6-dibromo-1,4-benzoquinone,2,3-dibromo-5,6-dimethyl-1,4-benzoquinone and 3,4,5,6-tetrabromo-1,2-benzoquinone,with an average concentration of 0.44-79.90 ng/L.2.Artificial sweeteners acesulfame(ACE)and sucralose(SUC)have been used as sewage marker.Some studies have been shown that they can react with chlorine-containing disinfectant to produce DBPs,thus they can be a precursor of DBPs.A rapid analytical method was developed to directly quantify the two artificial sweeteners.The detection limits for ACE and SUC were 1.75 ng/L and 0.03 ng/L.The concentrations of ACE and SUC in drinking water in Wuhan were 97.57-264.01 ng/L and 0-113.95 ng/L respectively,and increasing in a downstream direction.The remaining water quality parameters showed that the raw water quality of the five drinking water plants of Wuhan was good.3.In the research of formation potential of HBQs,the functions of three disinfectants in drinking water were simulated to analyze the relationship with the formation of HBQs.The results showed that different disinfection methods had different effects on the formation of HBQs.Among them,the ozone disinfectant presented its greatest potential to generate HBQs,followed by chloramine disinfection,and sodium hypochlorite disinfection was the least.In addition,five precursors that may produce HBQs under chlorination were examined.The results showed that none of the five precursors could generate 2,3-dibromo-5,6-dimethyl-1,4-benzoquinone under chlorination,while p-cresol could form 2,5-dichloro-1,4-benzoquinone,and the generated amount increased with the increasing p-cresol concentration in the raw water.The precursors producing the diversities of Cl-HBQs in chlorination were set as the following order: phenol > p-cresol > phenylalanine > tyrosine > toluene,and for the formation diversities of Br-HBQs in chlorination,the precursors were sorted as: phenylalanine > tyrosine > toluene > p-cresol > phenol.All in all,the disinfection mode and precursor have important influence on the formation of HBQs in drinking water.