Determination of Essential (Ca, Fe, I, K, Mo) and Toxic Elements (Hg, Pb) in Brazilian Rice Grains and Estimation of Reference Daily Intake

Abstract

The levels of Hg and Pb (toxic elements) and Ca, Fe, I, K, Mo (essential elements) were measured in 44 Brazilian rice samples divided among white polished (W), parboiled white (PW) and parboiled brown (PB). Rice grains were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Concentrations of toxic elements varied from 0.3 to 13.4 and 0.4 to 14.5 ng·g–1 for Hg and Pb, respectively. The values for essential elements were in the same range of those for rice produced in other countries. In general parboiled samples presented higher levels of all elements in study compared to white samples. The Estimated Daily Intake through rice consumption was 0.44 µg for Pb, 0.22 µg for Hg, 0.65 µg for I, 39.5 µg for Mo, 0.43 mg for Fe, 4.1 mg for Ca and 88.9 mg for K. Our findings demonstrated that rice can contribute significantly to the RDIs of molybdenum and potassium, but it can not be considered an important source of I, Fe and Ca. Moreover, the estimated daily intake of lead and mercury through rice consumption is much lower than the Provisional Tolerable Daily Intake.