title: Occurrences of nitrosamines in chlorinated and chloraminated drinking water in three representative cities, China.
abstract: An investigation of the occurrence of nine nitrosamines in drinking water following different water treatment processes was conducted using samples from seven drinking water treatment plants in three cities and tap waters in one city in China. The total nitrosamine levels ranged from not detected (n.d.) to 43.45 ng/L. The species and concentrations of the nine nitrosamines varied with disinfection methods and source waters. N-nitrosodimethylamine (NDMA), which is the nitrosamines of greatest concern, was identified in raw water, disinfecting water, finished water and tap water samples, ranging from 0.8 to 21.6, 0.12 to 24.2, n.d. to 8.8, and n.d. to 13.3 ng/L, respectively. Chloramination alone produced the most significant amounts of NDMA, while ozonation followed by chloramination led to moderately reduced levels. Additionally, chlorination produced relatively less NDMA, while low pressure ultraviolet radiation followed by chlorination could also significantly reduce them. Total organic carbon is one of the most important factors influencing nitrosamines formation in disinfecting water. In contrast, the addition of chlorine following any other disinfection was found to increase the formation of the other eight species of nitrosamines. The three nitrosamines recommended for monitoring by the US EPA were detected in the tap water samples, but most were present at levels below those that pose a risk to human health. Nevertheless, the occurrence and concentration of nitrosamines regulated in the Drinking Water Contaminant Candidate List could cause some potential human effects and therefore warrant attention.
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Luo
authors.forename: Donghong
authors.initials: D
authors.lastname: Wang
authors.forename: Zijian
authors.initials: Z
authors.lastname: Wang
mesh_terms: D002681:China; D002700:Chloramines / Q000032:analysis*; D017606:Chlorine Compounds / Q000032:analysis* / Q000138:chemical synthesis; D002947:Cities; D004128:Dimethylnitrosamine / Q000032:analysis; D004202:Disinfectants / Q000032:analysis*; D060766:Drinking Water / Q000032:analysis*; D006801:Humans; D009602:Nitrosamines / Q000032:analysis* / Q000138:chemical synthesis; D009930:Organic Chemicals / Q000032:analysis / Q000138:chemical synthesis; D010126:Ozone / Q000737:chemistry*; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000138:chemical synthesis; D018508:Water Purification / Q000379:methods*; D060753:Water Quality; D014881:Water Supply / Q000032:analysis
chemical_list: D002700:Chloramines; D017606:Chlorine Compounds; D004202:Disinfectants; D060766:Drinking Water; D009602:Nitrosamines; D009930:Organic Chemicals; D014874:Water Pollutants, Chemical; D010126:Ozone; D004128:Dimethylnitrosamine