title: Peptide bonds affect the formation of haloacetamides, an emerging class of N-DBPs in drinking water: free amino acids versus oligopeptides.
abstract: Haloacetamides (HAcAms), an emerging class of nitrogenous disinfection by-products (N-DBPs) of health concern, have been frequently identified in drinking waters. It has long been appreciated that free amino acids (AAs), accounting for a small fraction of the dissolved organic nitrogen (DON) pool, can form dichloroacetamide (DCAcAm) during chlorination. However, the information regarding the impacts of combined AAs, which contribute to the greatest identifiable DON portion in natural waters, is limited. In this study, we compared the formation of HAcAms from free AAs (tyrosine [Tyr] and alanine [Ala]) and combined AAs (Tyr-Ala, Ala-Tyr, Tyr-Tyr-Tyr, Ala-Ala-Ala), and found that HAcAm formation from the chlorination of AAs in combined forms (oligopeptides) significantly exhibited a different pattern with HAcAm formation from free AAs. Due to the presence of peptide bonds in tripeptides, Tyr-Tyr-Tyr and Ala-Ala-Ala produced trichloroacetamide (TCAcAm) in which free AAs was unable to form TCAcAm during chlorination. Moreover, peptide bond in tripeptides formed more tri-HAcAms than di-HAcAms in the presence of bromide. Therefore, the peptide bond may be an important indicator to predict the formation of specific N-DBPs in chlorination. The increased use of algal- and wastewater-impacted water as drinking water sources will increase health concerns over exposure to HAcAms in drinking water.
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
authors.forename: Wenhai
authors.initials: W
authors.lastname: Chu
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
authors.forename: Naiyun
authors.initials: N
authors.lastname: Gao
authors.affiliation: Department of Earth and Environmental Studies, Montclair State University, Montclair, NJ 07043, USA.
authors.forename: Yang
authors.initials: Y
authors.lastname: Deng
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
authors.forename: Daqiang
authors.initials: D
authors.lastname: Yin
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Li
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
authors.forename: Tengfei
authors.initials: T
authors.lastname: Chu
mesh_terms: D000081:Acetamides / Q000032:analysis / Q000737:chemistry*; D000596:Amino Acids / Q000737:chemistry; D062845:Chloroacetates / Q000032:analysis / Q000737:chemistry*; D004151:Dipeptides / Q000737:chemistry; D004202:Disinfectants / Q000032:analysis / Q000737:chemistry*; D004203:Disinfection; D060766:Drinking Water / Q000032:analysis* / Q000737:chemistry; D054879:Halogenation / Q000502:physiology; D009584:Nitrogen / Q000737:chemistry; D009842:Oligopeptides / Q000737:chemistry; D062065:Wastewater / Q000032:analysis* / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D000081:Acetamides; D000596:Amino Acids; D062845:Chloroacetates; D004151:Dipeptides; D004202:Disinfectants; D060766:Drinking Water; D009584:Nitrogen; D009842:Oligopeptides; D062065:Wastewater; D014874:Water Pollutants, Chemical; C042696:tyrosyltyrosine; C016968:alanyltyrosine; C039944:alanyl-alanyl-alanine; C032619:2,2-dichloroacetamide; C009528:trichloroacetamide