Bioaccessibility of 12 trace elements in marine molluscs

We conducted a large scale investigation of the bioaccessibility of 12 trace elements from 11 marine mollusc species (scallop, oyster, clam, abalone, snail, and mussel) collected from five locations in Chinese coastal waters. The bioaccessibility of all the 12 trace elements was generally high, with the average values ranging from 42.5% to 90.7%. The highest bioaccessibility was observed for As, Cu, Ni and Se, and the lowest for Fe, Co and Pb. Steaming decreased the bioaccessibility of all 12 trace elements and thus diminished their risks. No correlation was observed between the bioaccessibility and the total concentration of the 12 elements. However, there was a significant correlation between the bioaccessibility of the 12 elements and their subcellular distribution. For most trace elements, a significantly negative relationship was demonstrated between the bioaccessibility and the elemental partitioning in the metal-rich granule fraction or in the cellular debris fraction, and a significantly positive correlation was observed between the bioaccessibility and the elemental partitioning in the heat-stable protein fraction and in the trophically available fraction. Hence, the elemental subcellular distribution, especially the elemental partitioning in the trophically available fraction, might be a good predictor of the bioaccessibility and risks of trace elements in molluscs.