Health Risk Of Organophosphate Esters And Identification Of Bisphenol A And Of Unknown Disinfection By-products In Drinking Water

To address the drinking water safety,the emerging environmental pollutants and new disinfection by-products（DBPs）were researched in this study.For emerging environmental pollutants,organophosphate esters（OPEs）were selected to research,due to their great bio-toxicity,endocrine disruption and carcinogenicity.During drinking water disinfection,emerging environmental pollutants could react with the chlorine to form DBPs with higher toxic.However,due to the structure stability,OPEs almost not react with chlorine to form DBPs.Bisphenol A（BPA）,a well known emerging environmental pollutant,endocrine disrupter and model compound,was used to study the DBPs during drinking water disinfection.In addition,although more than 700 DBPs have been identified in drinking water,more than 70%of DBPs in drinking water are still unknown.Therefore,in our study,the unknown DBPs were also studied using higher resolution mass spectrum（HRMS）.The main conclusions are shown in following paragraphs:（1）OPEs widely occurred in drinking water of Chinese cities with a total concentration of 13.42-265.48 ng/L.Compared to other countries,the pollution of OPEs in China was at a medium and/or low level.The serious pollution occurred in Northeast China,Pearl River Delta,Yangtze Delta,Hebei Province and Chongqing City.The occurrence and distribution of OPEs in drinking water of China have a good corresponding relationship with the Aihui-Tengchong Line（2）Drinking water is an important pathway of OPEs exposure.Compared with non-cancer risk,cancer risk could be a more sensitive tool for revealing the threats of OPEs to human health,suggesting more attention should be paid on cancer risk of OPEs.Health risk assessment suggested that potential cancer risk occurred for OPEs but not serious(>10^-6but<10^-5).In addition,no obvious non-cancer effects occurred（<1）.The distribution of health risk of OPEs did not have gender difference,and the serious risk was observed in Jilin Province,followed by the Pearl River Delta and Yangtze Delta.Advanced drinking water treatment technology could reduce about65.6%and 36.5%of cancer risk and non-cancer risk,respectively.（3）Based on mass spectrum technology,30 halogenated BPAs were identified and 18 of them were never reported before.In both chlorination and chloramination,iodide could increase the transformation rate of BPA.However,during chloramination,since limited HCl O/Cl O^-formed,the transformation rate of BPA was much lower than that of chlorination.Based on observed halogenated BPAs,the reaction pathways,reaction scheme and bromine and iodide recycling of BPA were proposed,which highlighted the catalytic role of iodide in the chlorination process.（4）Based on HRMS,a group of new DBPs,halogenated cyclopentadienes were identified in both chlorinated and chloraminated drinking water,including hexachlorocyclopenta-1,3-diene,pentachlorocyclopenta-1,3-diene,tetrachlorocyclopentadiene,and trichlorocyclopenta-1,3-diene.Compared with chloramination,halogenated cyclopentadienes are more easily formed during chlorination.