The methylation of mercury by the gastro-intestinal contents of the rat.

Bacteria in the sediments of lakes and rivers, and in soil, have been shown to convert inorganic mercury salts into the more toxic methylmercury and dimethylmercury, which are absorbed from the human gastrointestinal tract much more rapidly than their inorganic counterparts (Jensen & Jernelov, 1969; Matsumura et al., 1972; Beckert et al., 1974; Clarkson, 1971). Abdulla et al. (1973) demolistrated the methylation of HgC& in rats with jejunal blind-loops, which suggests that small amounts of methylmercury may be formed by the microbial flora of the gut. In the present communication, the ability of suspensions of rat caecal and small intestinal contents to synthesize methylmercury is demonstrated.