Toxic Metals and Metalloids in Hassawi Brown Rice: Fate during Cooking and Associated Health Risks

Abstract

Rice has been a dietary staple for centuries, providing vital nutrients to the human body. Brown rice is well known for its nutrient-dense food profile. However, owing to multiple causes (anthropogenic and non-anthropogenic), it can also be a potential source of toxic heavy metals in the diet. Brown Hassawi rice samples were collected from the Al-Ahsa region and analyzed for its content of toxic metals. The results reveal that all the tested metals varied significantly in the brown rice samples, while As and Pb in all three samples exceeded their respective maximum allowable limits (MALs), followed by Cd, which nearly approached the MAL in two samples out of three. Brown rice samples were cooked in rice:water systems, viz., low rice:water ratios (1:2.5, 1:3.5) and high rice:water ratios (1:5, 1:6), along with soaking as a pre-treatment. Soaking was unproductive in removing the heavy metals from the rice, whereas cooking dissipated all metals from the rice, except for Cd, which was statistically non-significant. The high-water cooking of the rice was more effective in the dissipation of metals from the rice as compared to low-water cooking conditions. Through the consumption of rice, the estimated daily intake (EDI) of heavy metals is 162 g per person per day for As, which is above the provisional maximum tolerable daily intake (PMTDI) regardless of cooking circumstances. The hazard risk index (HRI) also highlighted the fact that As can be a potential health hazard to rice consumers in the Al-Ahsa region of Saudi Arabia. These results indicate the potential health risks caused by the consumption of this rice by humans. Regular monitoring is recommended to manage and control elevated concentrations and related health hazards as a result of the use of Hassawi rice contaminated by the accumulation of metals and metalloids.