Inorganic arsenic in the Japanese diet: daily intake and source.

The concentrations of arsenic (As) species in 19 food composites prepared from 159 food items purchased in Shizuoka city, Japan, were determined (1) to estimate total daily intake of inorganic As (InAs) and some organic As species and (2) to determine food contributing to total daily InAs intake. As analysis included extraction of As species with a synthetic gastric juice (0.07 mol/L HCl + 0.01 % pepsin) from food composite and high-performance liquid chromatography-high efficiency photo-oxidation-hydride generation-inductively coupled plasma mass spectrometry. InAs was detected in 9 of 19 food composites at a concentration of 0.423-450 ng As/g fresh-weight. Daily intake of InAs from cereals was greatest (13 μg/person/day) followed by algae (5.7 μg/person/day), and the intake from the two categories constituted 90 % of the total daily InAs intake of adults (21 μg/person/day on a bioaccessible-fraction basis and 24 μg/person/day on a content basis). Analysis of individual food items showed that rice and hijiki contributed virtually 100 % of InAs from cereals and algae, respectively. The present survey indicated that InAs from rice and hijiki consumption contributed to total daily InAs intake and consequently to significant cancer risk of the general Japanese population. Daily intake of some organic forms of As and their contributing food categories was also estimated.