title: Urinary arsenic metabolites in children and adults exposed to arsenic in drinking water in Inner Mongolia, China.
abstract: BACKGROUND
  We report the concentrations and distributions of urinary arsenic (As) metabolites in 233 residents exposed to 20, 90, or 160 microg/L inorganic arsenic (iAs) in drinking water from three villages in Hohhot, Inner Mongolia, China, that formed one control and two exposed groups.
  
  
  METHODS
  We used hydride generation-atomic absorption spectrometry (HGAAS) to determine iAs, monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA).
  
  
  RESULTS
  The concentrations of each urinary As species in the two exposed groups were significantly higher than in the control group for both children and adults. Both children and adults in exposed groups had higher percent iAs and MMA and lower percent DMA, and low primary and secondary methylation indices (PMI and SMI, respectively) than those in the control group. However, children showed significant increases in percent DMA and the SMI as well as decreases in the percent MMA when the iAs exposure level increased from 90 to 160 microg/L. In addition, children in the two exposed groups showed lower percent MMA but higher percent DMA and higher SMI than adults in the same exposed group. No significant differences in As metabolite concentrations and distributions were found between males and females in each group. A significant correlation was also found in the SMI between 11 pairs of children and their mothers from the 160-microg/L-exposed group.
  
  
  CONCLUSIONS
  Children had higher a capacity for secondary methylation of As than adults when exposed to the same concentrations of iAs in drinking water. Exposure to As may increase the capacity for methylation in children to some extent.
authors: Department of Environmental and Occupational Health, College of Public Health, China Medical University, No. 92 Bei Er Road, Heping District, Shenyang 110001, People's Republic of China. sunf@mail.cmu.edu.cn
authors: Guifan
authors: G
authors: Sun
authors: Yuanyuan
authors: Y
authors: Xu
authors: Xin
authors: X
authors: Li
authors: Yaping
authors: Y
authors: Jin
authors: Bing
authors: B
authors: Li
authors: Xiance
authors: X
authors: Sun
mesh_terms: D000328:Adult; D000367:Age Factors; D001151:Arsenic / Q000378:metabolism* / Q000652:urine*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D002681:China; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000378:metabolism* / Q000652:urine*; D005260:Female; D006801:Humans; D008297:Male; D008745:Methylation; D014881:Water Supply
chemical_list: D004785:Environmental Pollutants; D001151:Arsenic