State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University , Nanjing, 210023, P.R. China.
Environ Sci Technol. 2016 Jul 5;50(13):7189-97. doi: 10.1021/acs.est.6b01533. Epub 2016 Jun 22.
Iron (Fe) is a common trace element in drinking water. However, little is known about how environmental concentrations of Fe affect the metabolism and toxicity of arsenic (As) in drinking water. In this study, influence of Fe at drinking water-related concentrations (0.1, 0.3, and 3 mg Fe (total)/L) on As metabolism and toxicity, and the roles of gut microbiota during this process were investigated by using in vitro Simulator of the Human Intestinal Microbial Ecosystem (SHIME). Results showed that Fe had ability to decrease bioaccessible As by coflocculation in small intestine. 0.1 and 0.3 mg/L Fe significantly increased As methylation in simulated transverse and descending colon. Gut microbiota played an important role in alteration of As species, and Fe could affect As metabolism by changing the gut microbiota. Bacteroides, Clostridium, Alistipes, and Bilophila had As resistance and potential ability to methylate As. Cytotoxicity assays of effluents from simulated colons showed that the low levels of Fe decreased As toxicity on human hepatoma cell line HepG2, which might be due to the increase of methylated As. When assessing the health risk of As in drinking water, the residual Fe should be considered.
铁（Fe）是饮用水中的一种常见微量元素。然而，人们对环境浓度的铁如何影响饮用水中砷（As）的代谢和毒性知之甚少。在这项研究中，使用体外人类肠道微生物生态系统模拟器（SHIME）研究了饮用水相关浓度（0.1、0.3 和 3 mg Fe（总）/L）的铁对砷代谢和毒性的影响，以及在此过程中肠道微生物群的作用。结果表明，铁具有通过小肠共絮凝降低生物可利用砷的能力。0.1 和 0.3 mg/L 的铁显著增加了模拟横结肠和降结肠中的砷甲基化。肠道微生物群在改变砷形态方面发挥了重要作用，铁可以通过改变肠道微生物群来影响砷的代谢。拟杆菌、梭菌、Alistipes 和Bilophila 具有砷抗性和潜在的将砷甲基化的能力。来自模拟结肠的流出物的细胞毒性测定表明，低水平的铁降低了砷对人肝癌细胞系 HepG2 的毒性，这可能是由于甲基化砷的增加。在评估饮用水中砷的健康风险时，应考虑残留的铁。
