title: Pharmaceuticals in tap water: human health risk assessment and proposed monitoring framework in China.
abstract: BACKGROUND
  Pharmaceuticals are known to contaminate tap water worldwide, but the relevant human health risks have not been assessed in China.
  
  
  OBJECTIVE
  We monitored 32 pharmaceuticals in Chinese tap water and evaluated the life-long human health risks of exposure in order to provide information for future prioritization and risk management.
  
  
  METHODS
  We analyzed samples (n = 113) from 13 cities and compared detected concentrations with existing or newly-derived safety levels for assessing risk quotients (RQs) at different life stages, excluding the prenatal stage.
  
  
  RESULTS
  We detected 17 pharmaceuticals in 89% of samples, with most detectable concentrations (92%) at < 50 ng/L. Caffeine (median-maximum, nanograms per liter: 24.4-564), metronidazole (1.8-19.3), salicylic acid (16.6-41.2), clofibric acid (1.2-3.3), carbamazepine (1.3-6.7), and dimetridazole (6.9-14.7) were found in ≥ 20% of samples. Cities within the Yangtze River region and Guangzhou were regarded as contamination hot spots because of elevated levels and frequent positive detections. Of the 17 pharmaceuticals detected, 13 showed very low risk levels, but 4 (i.e., dimetridazole, thiamphenicol, sulfamethazine, and clarithromycin) were found to have at least one life-stage RQ ≥ 0.01, especially for the infant and child life stages, and should be considered of high priority for management. We propose an indicator-based monitoring framework for providing information for source identification, water treatment effectiveness, and water safety management in China.
  
  
  CONCLUSIONS
  Chinese tap water is an additional route of human exposure to pharmaceuticals, particularly for dimetridazole, although the risk to human health is low based on current toxicity data. Pharmaceutical detection and application of the proposed monitoring framework can be used for water source protection and risk management in China and elsewhere.
authors.affiliation: State Key Laboratory in Marine Pollution, and Department of Biology and Chemistry, City University of Hong Kong, Hong Kong Special Administrative Region, China.
authors.forename: Ho Wing
authors.initials: HW
authors.lastname: Leung
authors.forename: Ling
authors.initials: L
authors.lastname: Jin
authors.forename: Si
authors.initials: S
authors.lastname: Wei
authors.forename: Mirabelle Mei Po
authors.initials: MM
authors.lastname: Tsui
authors.forename: Bingsheng
authors.initials: B
authors.lastname: Zhou
authors.forename: Liping
authors.initials: L
authors.lastname: Jiao
authors.forename: Pak Chuen
authors.initials: PC
authors.lastname: Cheung
authors.forename: Yiu Kan
authors.initials: YK
authors.lastname: Chun
authors.forename: Margaret Burkhardt
authors.initials: MB
authors.lastname: Murphy
authors.forename: Paul Kwan Sing
authors.initials: PK
authors.lastname: Lam
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D002681:China; D002851:Chromatography, High Pressure Liquid; D002947:Cities; D060766:Drinking Water / Q000032:analysis*; D004781:Environmental Exposure; D004784:Environmental Monitoring / Q000379:methods*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D004364:Pharmaceutical Preparations / Q000032:analysis*; D018570:Risk Assessment; D053719:Tandem Mass Spectrometry; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification; D055815:Young Adult
chemical_list: D015415:Biomarkers; D060766:Drinking Water; D004364:Pharmaceutical Preparations; D014874:Water Pollutants, Chemical