title: Applying the polarity rapid assessment method to characterize nitrosamine precursors and to understand their removal by drinking water treatment processes.
abstract: Some N-nitrosamines (NAs) have been identified as emerging disinfection by-products during water treatment. Thus, it is essential to understand the characteristics of the NA precursors. In this study, the polarity rapid assessment method (PRAM) and the classical resin fractionation method were studied as methods to fractionate the NA precursors during drinking water treatment. The results showed that PRAM has much higher selectivity for NA precursors than the resin approach. The normalized N-nitrosodimethylamine formation potential (NDMA FP) and N-nitrosodiethylamine (NDEA) FP of four resin fractions was at the same level as the average yield of the bulk organic matter whereas that of the cationic fraction by PRAM showed 50 times the average. Thus, the cationic fraction was shown to be the most important NDMA precursor contributor. The PRAM method also helped understand which portions of the NA precursor were removed by different water treatment processes. Activated carbon (AC) adsorption removed over 90% of the non-polar PRAM fraction (that sorbs onto the C18 solid phase extraction [SPE] cartridge) of NDMA and NDEA precursors. Bio-treatment removed 80-90% of the cationic fraction of PRAM (that is retained on the cation exchange SPE cartridge) and 40-60% of the non-cationic fractions. Ozonation removed 50-60% of the non-polar PRAM fraction of NA precursors and transformed part of them into the polar fraction. Coagulation and sedimentation had very limited removal of various PRAM fractions of NA precursors.
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China; College of Civil Engineering, Huaqiao University, Xiamen, 361021, China.
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Liao
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China.
authors.forename: Er
authors.initials: E
authors.lastname: Bei
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China.
authors.forename: Shixiang
authors.initials: S
authors.lastname: Li
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China.
authors.forename: Yueying
authors.initials: Y
authors.lastname: Ouyang
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China. Electronic address: chen_water@tsinghua.edu.cn.
authors.forename: Chao
authors.initials: C
authors.lastname: Chen
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China.
authors.forename: Xiaojian
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Metropolitan Water District of Southern California, 700 Moreno Avenue, La Verne, CA 91750, USA.
authors.forename: Stuart W
authors.initials: SW
authors.lastname: Krasner
authors.affiliation: Department of Environmental Health Sciences, School of Public Health, UCLA, 90095, USA.
authors.forename: I H Mel
authors.initials: IH
authors.lastname: Suffet
mesh_terms: D005591:Chemical Fractionation; D060766:Drinking Water / Q000032:analysis* / Q000737:chemistry; D009602:Nitrosamines / Q000032:analysis* / Q000737:chemistry; D018508:Water Purification / Q000379:methods*
chemical_list: D060766:Drinking Water; D009602:Nitrosamines
keywords: Disinfection by-product; Drinking water treatment process; Nitrosamine; Polarity rapid assessment method; Precursor; Resin fractionation