| Urinary Arsenic Metabolites in Children and Adults Exposed to Arsenic
in Drinking Water in Inner Mongolia, China Guifan Sun, Yuanyuan Xu, Xin Li, Yaping Jin, Bing Li, and Xiance Sun Department of Environmental and Occupational Health, College of Public Health, China Medical University, Shenyang, Liaoning, People's Republic of China Abstract
Background: We report the concentrations and distributions of urinary arsenic (As) metabolites in 233 residents exposed to 20, 90, or 160 µg/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 µg/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-µg/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. Key words: arsenic, children, drinking water, metabolism, methylation. Environ Health Perspect 115:648–652 (2006) . doi:10.1289/ehp.9271 available via http://dx.doi.org/ [Online 9 January 2007]
This article is part of the mini-monograph "Occurrence and Health Effects of Arsenic in China." Address correspondence to G. Sun, Department of Environmental and Occupational Health, College of Public Health, China Medical University, No. 92 Bei Er Rd., Heping District, Shenyang, 110001, People's Republic of China. Telephone: 86 24 2326 1744. Fax: 86 24 2326 1744. E-mail: sunf@mail.cmu.edu.cn. We thank the people of Inner Mongolia for participating in this study. We also thank Y. Zheng for her comments during the manuscript preparation. This work was supported by National Natural Science Foundation of China (NSFC) research grant 30530640. The authors declare they have no competing financial interests. Received 17 April 2006 ; accepted 20 September 2006.
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