Uncertainty and sensitivity analyses of human health risk from bioaccessible arsenic exposure via rice ingestion in Bangkok, Thailand

BACKGROUND Rice can be a source of arsenic (As) exposure, causing health impacts after ingestion. OBJECTIVE This study analyzed health risks due to As exposure through rice consumption, focusing on both bioaccessible (bAs) and total (tAs) As levels. METHODS Monte Carlo simulations were applied to determine health risk uncertainties and to analyze factors influencing health risks. RESULTS Cooked white and brown rice contained lower tAs and bAs than FAO/WHO standards of 0.20 and 0.35 mg/kg, respectively. As became less bioaccessible after cooking (14.0% in white rice and 18.5% in brown rice). Non-carcinogenic effects (MOS < 1) were found in 5% of children. Carcinogenic effects (MOE<100), especially lung cancer, were found in 75% of adults, with a probable incidence of 7 in 1,000,000. The lowest and highest annual cancer cases were 18 in 10,000,000 adolescents and 15 in 1,000,000 adults, respectively. The risks were mainly affected by body weight and bAs concentration. SIGNIFICANCE The results identified a certain risk level of non-carcinogenic effects in children and adolescents as well as carcinogenic effects in adults. The per capita consumption of rice in Thai adults should be reduced to prevent incidences of lung cancer.