应用SHIME模型研究肠道微生物对土壤中镉、铬、镍生物可给性的影响

为了研究人体肠道微生物对土壤中Cd、Cr、Ni生物可给性的影响.本文采集我国一些地区的5种土壤,利用in vitro方法(PBET和SHIME联用)研究了这些土壤中Cd、Cr、Ni在胃、小肠、结肠阶段的生物可给性及其对人体的健康风险.结果表明,土壤中Cd、Cr、Ni在胃阶段的生物可给性分别为4.3%~94.0%、6.4%~21.6%、11.3%~47.3%;小肠阶段,土壤中Cr和Ni的生物可给性与胃阶段一致或有一定升高,但Cd的生物可给性降低了1.4~1.6倍(土壤2除外);胃肠阶段,Cd的平均生物可给性较高,而Cr的较低.结肠阶段,土壤中Cr和Ni的生物可给性均升高,是小肠阶段的1.3~2.4倍和1.0~2.1倍,分别达到了17.6%~38.7%和25.4%~56.0%;而Cd的生物可给性也升高(土壤3和4除外);Ni的平均生物可给性最高.由此可见,肠道微生物可以促进土壤中Cd、Cr、Ni的溶出释放,提高了三者的生物可给性,可能增大了人体的健康风险.

Effects of Human Gut Microbiota on Bioaccessibility of Soil Cd, Cr and Ni Using SHIME Model

The influence of human gut micobiota on bioaccessibilities of soil Cd, Cr, and Ni were investigated in this study. Five soil samples were collected from some sites of China, and the bioaccessibilities of soil Cd, Cr, and Ni in the gastric, small intestinal, and colon phases were determined using the PBET method (physiologically based extraction test) combined with SHIME model (simulator of human intestinal microbial ecosystem). The results showed that the bioaccessibilities of Cd, Cr, and Ni in the gastric phase were 4.3%-94.0%, 6.4%-21.6%, and 11.3%-47.3%, respectively. In the small intestinal phase, the bioaccessibilities of Cr and Ni were either congruent or slightly increased, while for Cd, the values were reduced by 1.4-1.6 folds except for soil 2. In the gastric and small intestinal phases, the mean bioaccessibility of Cd was higher but that of Cr was lower. In the colon phase, the bioaccessibilities of Cr and Ni were 1.3-2.4 and 1.0-2.1 times higher than those in the small intestinal phase. Furthermore, the bioaccessibility of Cd also increased except for soil 3 and 4. Human gut micobiota could induce Cd, Cr, and Ni release from soils and increase their bioaccessibilities, which may result in high risk to human health.