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

Abstract

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.