Cancer Risk Assessment of Inorganic Arsenic Among Japanese Population

Abstract

PP-30-093 Background/Aims: Japanese people consume large amounts of seafood and seaweed containing arsenic at high concentration. Most of the arsenicals are organic with low toxicity; however, the foods also contain trace amount of inorganic arsenic (iAs), which is a human toxicant and carcinogen. However, to date, detailed exposure assessment of iAs in Japanese has not been carried out. In this study, we estimated daily iAs intake of 25 Japanese from diet and other exposure sources (soil, indoor dust, and ambient air), and we assessed their cancer risk posed by the iAs exposure. Methods: Duplicate portion diet samples were collected from 25 households, and soil and indoor dust samples were from the other 20 households. These samples were extracted by a synthetic gastric juice to obtain bioaccessible fraction. The concentration of iAs in the bioaccessible fraction was measured by LC-ICP-MS with a photo-oxidation/hydride generation system. Inhalation iAs intake was estimated by atmospheric monitoring data. Results: The median daily consumption of dietary iAs was estimated to be 3.84 μg/d with the range of 1.98–57.1 μg/d. The estimated iAs intakes from nondietary oral sources and inhalation were negligible (<1% of dietary intake or 0.0286–0.100 μg/d) when default soil/indoor dust ingestion rate and inhalation rate were assumed. The maximum dietary intake of iAs was observed for the person who ate Hijiki seaweed (Sargassum fusiforme) on the sampling day. Based on this result and EPA Oral Slope Factor (1.5[mg/kg/d]-1), skin cancer risk of Japanese was estimated to be 1.4 × 10−[graphic]. Conclusion: Cancer risk posed by the iAs intake of Japanese may be significant.