Determination of Arsenic in Thai Rice

Studies have shown that rice (Oryza sativa L.) is one of the main sources of inorganic arsenic in foods. Rice absorbs arsenic from the soil and more so when planted in soils contaminated with agrochemicals residues. In this research, the concentration of arsenic in over 40 rice samples, selected randomly from paddy fields in the North of Thailand, was determined by inductively coupled plasma–mass spectrometry (ICP-MS). It was found that the average levels of arsenic in rice grown in uncontaminated soil was 1.8 x10-3 mg kg-1 (1.8 ppb) relatively lower than the guideline of 0.2 mg kg-1 (200 ppb) agreed by Codex Alimentarius for arsenic in rice. Thus, it is possible to suggest that a normal intake of Thai rice from the paddy fields of North Thailand, would not pose any significant adverse health effect on the consumer and import restriction of such produce on the ground of safety will be unreasonable.