Toxic metals in packed rice: Effects of size, type, origin, packing season, and storage duration

Abstract

The aim of our study was to quantify toxic metals in rice, to determine factors affecting its contamination, and evaluate exposure from its consumption in Lebanon and United Arab Emirates (UAE). For this, a market screening was done and all brands (107 from Lebanon and 129 from UAE) were collected twice and tested using ICP-MS. For As, Cd, Hg and Pb, in UAE, 9%, 1%, 100%, and 69% of samples exceeded the international limits, while in Lebanon, 25%, 73%, 100%, and 69% of samples were above limits, respectively. For As, in Lebanon, brown rice, long grains and brands from developed countries were significantly more contaminated, while in UAE, packing season, country of origin, and collection time had significant effect. For Cd, collection time had significant effect in Lebanon and UAE. Regarding Cr, in Lebanon, country of origin, grain size, rice type, and time between packing and purchasing had significant effect, while in UAE, collection time had significant effect. For Hg, collection time had significant effect in Lebanon and UAE. Alarming exposure levels for Hg and Pb from rice were detected in the UAE. Future studies must assess the effects of handling and cooking to better assess exposure to toxic metals from rice consumption.