Quantification of aluminum and heavy metal contents in cooked rice samples from Thailand markets using inductively coupled plasma mass spectrometry (ICP-MS) and potential health risk assessment
This work quantified contents of Al and heavy metals, namely Cr, Fe, Cu, Zn, As, Cd, and Pb, in cooked rice samples prepared using five different cooking utensils (new and used Al cookers, a Teflon-coated Al cooker, a stainless steel cooker, and a glass beaker) and four different water conditions (tap water, de-ionized water, acidic water, and basic water) in order to assess metal leaching from cooking utensils and potential health risks to local consumers. The result showed that Al contents (76.50 mg kg-1 in raw rice and 76.83 mg kg-1 in cooked rice samples) and Zn contents (22.86 mg kg-1 in raw rice and 22.43 mg kg-1 in cooked rice samples) represented the two largest contents of tested elements, in which contents of Al > Zn > Fe > Pb ≈ Cu > Cr >As ≈ Cd. However, no strong indication of substantial metal leaching from cooking utensils to cooked rice were observed in this work as the metal contents in cooked rice samples did not significantly differ from raw rice grains (p < 0.05). The result also indicated that the estimated weekly intake of Al and Pb associated with rice consumption of a person who consumed approximately 0.3 kg of rice per day (181.07 mg kg-1 week-1 and 4.85 mg kg-1 week-1, respectively) was greater than the provisional tolerance weekly intake (PTWI) recommended by the joint FAO/WHO committee for a person who weighs 60 kg (120 mg kg-1 week-1 and 1.5 mg kg-1 week-1, respectively). In terms of the assessment of non-carcinogenic and carcinogenic health risks, the hazard index (HI) calculated from all concerned metals was 9.18, with the largest contributions from Pb (3.19), As (2.67), and Al (1.51), indicating a potential non-carcinogenic risk, while the total cancer risk (CRt) was 2.45´10-2, with the largest contributions from Pb (1.0´10-2) and Cd (1.2´10-2), indicating serious carcinogenic risks to local consumers.