College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 101408, China; Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Sci Total Environ. 2018 Dec 10;644:815-821. doi: 10.1016/j.scitotenv.2018.07.003. Epub 2018 Jul 11.
Arsenic (As) is a highly toxic contaminant in food and soil. In this study, we investigated the effects of four nutritional states (including a fed state with vitamin C, a fed state with protein powder, a fed state with glucose and a fasted state) on the variability of soil As bioaccessibility and biotransformation using the physiologically based extraction test (PBET) combined with a simulator of the human intestinal microbial ecosystem model (SHIME). The results indicated that the vitamin C and protein powder increased As bioaccessibility in gastric digests. In the colon phase, As bioaccessibility was observably enhanced by protein powder, and it varied under the vitamin C and glucose conditions. Additionally, the order of As methylation percentages in the four nutritional states was protein powder > vitamin C > fasted state > glucose (except S2); As bioaccessibility increased 1.3-13.7% and 15.8-35.4% in treatments of the vitamin C and protein powder, respectively. Meanwhile, large amounts of monomethylarsonic acid (MMA) were observed in the colon digest in the protein powder condition. In contrast, As methylation was significantly decreased with the addition of glucose, with a decline of 25.9-45.5%. Additionally, glucose enhanced the reduction of As(V). Therefore, nutritional status is a crucial parameter for the prediction of bioaccessibility and speciation of As when assessing health risks from As following oral exposure.
砷（As）是食物和土壤中一种毒性很强的污染物。本研究采用基于生理学的提取试验（PBET）与人类肠道微生物生态系统模型模拟器（SHIME）相结合，研究了四种营养状态（包括维生素 C 喂养状态、蛋白粉喂养状态、葡萄糖喂养状态和禁食状态）对土壤砷生物可给性和生物转化变异性的影响。结果表明，维生素 C 和蛋白粉增加了胃消化液中的砷生物可给性。在结肠阶段，蛋白粉显著增强了砷的生物可给性，而在维生素 C 和葡萄糖条件下则有所变化。此外，四种营养状态下的砷甲基化百分比顺序为蛋白粉＞维生素 C＞禁食状态＞葡萄糖（S2 除外）；维生素 C 和蛋白粉处理分别使砷生物可给性增加了 1.3-13.7%和 15.8-35.4%。同时，在蛋白粉条件下，结肠消化物中观察到大量的一甲基砷酸（MMA）。相比之下，葡萄糖的添加显著降低了砷的甲基化，降幅为 25.9-45.5%。此外，葡萄糖增强了 As(V)的还原。因此，在评估口服暴露后砷的健康风险时，营养状态是预测砷生物可给性和形态的关键参数。
