Daily intake of inorganic arsenic and some organic arsenic species of Japanese subjects

The daily dietary intake of inorganic arsenic (InAs) and some of organic arsenic (OrAs) species of Japanese subjects were estimated by determining the concentrations of As species in two different sets of total diet sample: duplicated diet samples collected from 25 subjects in Japan and a certified reference material with total diet matrix (NIES CRM No. 27 Typical Japanese Diet, TJD). The concentration of InAs and OrAs in diet samples were determined by LC-ICP-MS using a photo-oxidation and hydride generation system. The median intake of InAs for the 25 subjects was 3.8 μg day−1 (2.0–57 μg day−1) and intake of 27 μg day−1 was estimated from TJD. The median intake of MMA, DMA and TMAsO were <0.18, 1.1 and <0.053 μg day−1 for the 25 subjects and that of MMA, DMA, AB and TMAsO was estimated to be 3.9, 11, 140 and 5.9 μg day−1, respectively, based on TJD analysis. On the basis of InAs intakes estimated and the oral slope factor of the US EPA and Health Canada, excess cancer risk was estimated to exceed acceptable level. Cancer risk posed by the dietary InAs of the general Japanese may not be negligible.