title: [Study for distribution level of disinfection byproducts in drinking water from six cities in China].
abstract: OBJECTIVE
  To find the distribution level and geographical variations of disinfection by-products (DBPs) in drinking water.
  
  
  METHODS
  The samples were selected from water utilities in six cities (Daqing, Beijing, Tianjin, Zhengzhou, Changsha and Shenzhen) of China. The water source and technology of water treatment were investigated and the indices including trihalomethanes (THMs) and haloacetic acids (HAAs) in main DBPs and natural organic materials (NOM), pH, chlorine dosage and temperature were determined.
  
  
  RESULTS
  In six cities the highest concentrations of TTHMs and THAAs in the distribution system were 92.8 microg/L and 40.0 microg/L, respectively. The concentration of every compound of THMs and HAAs was under the limit of standards for drinking water quality, but the concentrations of 'TTHMs at some samples were higher than the maximum acceptable level (MAC) defined by standards for drinking water quality. The geographical variations of THMs and HAAs in six cities were Zhengzhou > Tianjin > Daqing > Beijing > Shenzhen > Changsha and Changsha > Tianjin > Shenzhen > Daqing > Zhengzhou > Beijing, respectively. The levels of THMs of drinking water at Tianjin and Zhengzhou were higher than the others and the levels of HAAs of drinking water at Changsha, Tianjin and Shenzhen were higher than the others. The seasonal variations of both groups of THMs and HAAs were high in summer and low in winter.
  
  
  CONCLUSIONS
  The pollution level of DBPs in drinking water from Chinese six cities were low. The concentration of DBPs related to seasonal. THMs distributed mainly to the North and HAAs distributed mainly to the South.
authors.affiliation: Beijing Center for Disease Control and Prevention, Beijing 100013, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Deng
authors.forename: Jianrong
authors.initials: J
authors.lastname: Wei
authors.forename: Xueli
authors.initials: X
authors.lastname: E
authors.forename: Wuyi
authors.initials: W
authors.lastname: Wang
authors.lastname: et al
mesh_terms: D000085:Acetates / Q000032:analysis*; D002681:China; D002947:Cities; D004202:Disinfectants / Q000009:adverse effects*; D060766:Drinking Water / Q000032:analysis*; D054879:Halogenation; D022882:Trihalomethanes / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification; D014881:Water Supply / Q000032:analysis / Q000706:statistics & numerical data
chemical_list: D000085:Acetates; D004202:Disinfectants; D060766:Drinking Water; D022882:Trihalomethanes; D014874:Water Pollutants, Chemical