Occurrence of nitrosamines and their precursors in drinking water systems around mainland China.
N-Nitrosamines (NAs) in drinking water have attracted considerable attention in recent years due to their high carcinogenicity, frequent occurrence, and their potential regulation. During the past three years, we have collected about 164 water samples of finished water, tap water, and source water from 23 provinces, 44 cities from large cities to small towns, and 155 sampling points all over China. The occurrence of NAs in the finished and tap water was much higher in China than that in the U.S. Nine NAs were measured and NDMA had the highest concentration. The occurrence of NDMA was in 33% of the finished waters of water treatment plants and in 41% of the tap waters. The average NDMA concentration in finished and tap waters was 11 and 13 ng/L, respectively. Formation potentials (FPs) of source waters were examined with an average NDMA FP of 66 ng/L. Large variations in NA occurrence were observed geographically in China and temporally in different seasons. The Yangtze River Delta area, one sub-area in East China, had the highest concentrations of NAs, where the average NDMA concentrations in the finished and tap water were 27 and 28.5 ng/L, respectively, and the average NDMA FP in the source water was 204 ng/L. NA control may be achieved by applying breakpoint free chlorination and/or advanced treatment of ozone - granular activated carbon process to remove the NA precursors before disinfection.
State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China.
Er
E
Bei
State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China.
Yuanyuan
Y
Shu
State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China.
Shixiang
S
Li
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.
Xiaobin
X
Liao
State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China.
Jun
J
Wang
State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China.
Xiaojian
X
Zhang
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.
Chao
C
Chen
Metropolitan Water District of Southern California, 700 Moreno Avenue, La Verne, CA, 91750, USA.
Stuart
S
Krasner
D002681:China; D004128:Dimethylnitrosamine; D004203:Disinfection; D060766:Drinking Water; D009602:Nitrosamines; D014874:Water Pollutants, Chemical; D018508:Water Purification; D060753:Water Quality
D060766:Drinking Water; D009602:Nitrosamines; D014874:Water Pollutants, Chemical; D004128:Dimethylnitrosamine
China; Disinfection by-products; Formation potential; Nitrosamines; Precursors; Survey; Water quality