Arsenic health risk assessment related to rice consumption behaviors in adults living in Northern Thailand.

The rice consumption behaviors of Thai citizens vary among regions. However, the influence of different consumption patterns on arsenic (As) exposure has never been reported. This study was conducted to investigate the effects of rice consumption behavior on As exposure levels. White rice (n = 96) and sticky rice (n = 63) samples were collected from local households in northern Thailand. The actual rice consumption behavior (type, frequency, and amount of rice consumed) was surveyed from the households where the rice samples were collected and used to calculate individual As exposures. The white rice (2.1%) and sticky rice (6.3%) samples contained inorganic As at higher concentrations than the Codex standard (0.2 mg kg-1). Approximately 58.3% of participants consumed white rice for breakfast and sticky rice for lunch and dinner, while 41.8% of participants consumed only white rice or sticky rice daily. Wide variations of As exposure (1 × 10-4 to 2 × 10-3 mg kg-1 day-1) were found. The average As exposure from only sticky rice consumption and combined rice consumption was 2 times higher than the As exposure from only white rice consumption. The rice ingestion rate was the most important factor affecting the level of As exposure resulting from the white rice-only and combined rice consumption patterns. For the combined rice consumption pattern, 45.7 to 93.5% of the total As exposure was from sticky rice consumption. Regarding individual characteristics, older and lower weight participants tended to consume lower amounts of rice. Thus, lower As exposure and fewer health impacts were found in those participants.