Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 11 A Datun Road, Beijing, 100101, People's Republic of China.
College of Resources and Environment, University of Chinese Academy of Sciences, Huairou, People's Republic of China.
Environ Geochem Health. 2020 Sep;42(9):2841-2851. doi: 10.1007/s10653-020-00523-4. Epub 2020 Feb 7.
Water quality improvement is the most efficient way to prevent arsenic exposure. After the cessation of arsenic ingestion, arsenic methylation capacity of the exposed population can change significantly. The factors associated with these changes remain poorly understood. Therefore, arsenic methylation capacity in a study cohort was estimated before and after water quality improvement in the present study. Results indicated that urinary content of the arsenic species in the study cohort significantly decreased after water quality improvement. In addition, the proportions of inorganic arsenic (%iAs) and monomethyl arsenic acid (%MMA) were significantly decreased, while proportions of dimethyl arsenic (%DMA) increased. The primary methylation index (PMI) and secondary methylation index (SMI) increased from 0.85 to 0.92 and 0.82 to 0.84, respectively. Arsenic species urinary content and arsenic methylation index varied slightly between the study cohort after water quality improvement and the control cohort. The rate of increase in PMI was higher than that in SMI. The study group aged 31-50 years had the highest increase in PMI. Logistic regression revealed that %DMA before water quality improvement was negatively associated with the increase in PMI, while %iAs were positively related, and %MMA were positively associated with the increase in SMI. It is concluded that urinary arsenic species content and arsenic methylation capacity increased to the levels of the control cohort after water quality improvement. An increase in primary arsenic methylation capacity may be a burden on the secondary arsenic methylation capacity. The main role of arsenic methylation capacity recovery may be the cessation of arsenic exposure.
水质改善是预防砷暴露最有效的方法。停止摄入砷后，暴露人群的砷甲基化能力可能会发生显著变化。这些变化的相关因素仍知之甚少。因此，本研究在水质改善前后对研究队列的砷甲基化能力进行了评估。结果表明，水质改善后，研究队列的尿砷形态含量显著降低。此外，无机砷（%iAs）和一甲基砷酸（%MMA）的比例显著降低，而二甲基砷（%DMA）的比例增加。主要甲基化指数（PMI）和次要甲基化指数（SMI）分别从 0.85 增加到 0.92 和从 0.82 增加到 0.84。水质改善后研究队列与对照组队列的尿砷形态和砷甲基化指数略有差异。PMI 的增长率高于 SMI。31-50 岁年龄组的 PMI 增长率最高。Logistic 回归显示，水质改善前的%DMA 与 PMI 的增加呈负相关，而 %iAs 与 PMI 的增加呈正相关，%MMA 与 SMI 的增加呈正相关。结论是，水质改善后，尿砷形态含量和砷甲基化能力增加到对照组水平。初级砷甲基化能力的增加可能对次级砷甲基化能力构成负担。砷甲基化能力恢复的主要作用可能是停止砷暴露。
