ELEMENTAL COMPOSITION OF RICE AND OTHER GRAINS FROM THE UNITED STATES AND OUTSIDE

The concentrations of toxic and essential metals in rice and other grains grown in the United States (US) and other countries were determined using Inductively Coupled Plasma Mass Spectrometer (ICPMS). Concentrations (in µg/kg) of toxic metals reported as median (IQR) were 217 (180 – 291), 4.5 (2.6-11), 17.4 (9.5-42), and 4.9 (2.7 – 6.4) for As, Pb, Cd, and Hg in brown rice from US respectively. White rice from Thailand, India and Italy showed a higher average toxic metal concentration (in µg/kg) 155 (58 – 183) for As 3.6 (2.0 – 96) for Pb, and 8.4 (3.1 – 27) for Cd compared to white rice from the US. Toxic metal concentrations (in µg/kg) in white rice from the US averaged at 131 (65- 202), 2.8 (0.2 – 32), 6.5 (1.7 – 71), and 3.9 (1.4 – 15) for As, Pb, Cd, and Hg, respectively. Other grains showed As, Pb, Cd, and Hg concentrations (in µg/kg) of 5.4(1.9 – 26), 4.6(1.2 – 80), 6.7 (1.2 – 49), and (0.2 - 2.6), respectively. Essential elements (Ca, Zn, Fe, Cu, Mg, Mn, Co, and Sr) concentrations in other grains were higher than rice samples. None of the samples exceeded the codex standards set for Pb and Cd, however, brown rice exceeded the standards for As (200 µg/kg). Our findings suggest that alternating or coupling rice with other grains in diet could reduce exposure to toxic metals including high As in brown rice and provide the required essential elements scarce in rice.