Multi-elemental bio-accessibility from long-grain rice for realistic risk assessment using on-line continuous leaching coupled to inductively coupled plasma mass spectrometry: The non‑arsenic side of the story

This study investigates the leaching of toxic (Cd and Pb) and essential elements (Cu, Fe and Zn) from organic white, organic brown and basmati rice using the continuous on-line leaching method and a conventional batch method. The samples were maintained at 37 °C while being sequentially leached by artificial saliva, gastric juice and intestinal juice. Elements released were determined by inductively coupled plasma mass spectrometry, revealing over 60 % bio-accessibility in most instances. The total concentrations of Cd (140-150 μg kg^-1) and Pb (150-170 μg kg^-1) are near or exceed regulations in Europe. Washing rice prior to cooking reduced the toxic elements concentration by up to 50 % while preserving essential elements. However, consuming less than half a serving could still pose a health risk to a 20-kg child. Correlations between temporal leaching profiles of different elements revealed common sources of those elements, which differed between rice types, potentially enabling rice discrimination.