Comparison of contamination levels and health risks of toxic metals in raw and home-cooked rice; A field study on some rural households of Northern Iran

Abstract

To date, the majority of studies have assessed the health risks of toxic metals (TMs) in raw rice and/or in rice that is cooked in the laboratory under controlled conditions. However, people usually consume rice that is cooked in metallic cookware using ordinary cooking water and various additives. Therefore, this study focused on the contamination levels of TMs in raw rice and rice cooked under real conditions by the rural households of northern Iran. The levels of As and Cd in the cooking water used in rural households were negligible. The As levels in raw and cooked rice were 257 ± 134 and 243 ± 28 μg/kg, respectively, and the corresponding values for Cd were 8.54 ± 6.94 and 8.64 ± 3.18 μg/kg, respectively. Probabilistic health risk assessment showed unacceptable health risks for the As contamination of both raw and home-cooked rice but with different probability distributions. Overall, this study showed that the cooking water with low TMs levels was not sufficient for the significant reduction of these contaminants in rice during home cooking. Therefore, it is essential to monitor the TMs levels in home-cooked rice, instead of raw and/or artificially cooked rice, for a more realistic assessment of attributed health risks to the general public.