Characterisation and chemometric evaluation of 21 trace elements in three edible seaweed species imported from south-east Asia

This study was performed to delineate a characterisation of 21 trace elements (Al, As, Be, Cd, Co, Cr, Cu, Fe, Hg, Mo, Mn, Ni, Pb, Sb, Se, Sn, Sr, Tl, U, V, and Zn), in 92 samples of edible seaweeds, belonging to three species (Laminaria Japonica, 16; Porphyra Yezoensis, 54; Undaria Pinnatifida, 22) produced in south-eastern Asiatic countries. Analytical method based on inductively coupled plasma mass spectrometry was used. The compliance of samples with current European regulations was investigated and the 26% of samples was found not-compliant for Cd level. The suitability of the method due to multi-elemental determination allowed a multivariate approach to study the differentiation between species and to investigate the contribution of each element in differentiation. Influence of the geographical origin onto trace element profile was evaluated, and correlation study between each pair of elements was performed by Pearson coefficients. Taxonomic genus and, although to a lesser extent, the geographic origin have a great influence on trace element profile. Comparison with other similar studies was also performed. Discussion on safety aspects concerning heavy metal exposure related to seaweed consumption has been addressed, by comparing the tolerable levels of the most important toxic elements and the intake brought by seaweed species. For some toxic metals, such as Al and Cd, a remarkable risk related to seaweed consumption has been assessed, though with differences between species.