Metals in Undaria pinnatifida (Harvey) Suringar and Sargassum muticum (Yendo) Fensholt edible seaweeds growing around Venice (Italy)

Undaria pinnatifida and Sargassum muticum are the most abundant invasive edible algae species that have colonized the hard substrate around Venice. The contents of Ca, Mg, Fe, Zn, Cu, Mn, Sr, Pb, Cr, Al, Co, Cd, Ni, As, Hg and Ba, were investigated by ICP-MS in seaweed samples collected (Spring 2013) in six different sites of Venice. A correlation analysis of the results was performed. Sargassum muticum exhibited overall higher contents than U. pinnatifida for many of the considered elements. The elemental contents in both species were in ranges comparable to those reported for seaweeds subjected to anthropogenic impact. Considering the French legislation as a working reference for Pb, Cd and inorganic As limits for seaweed for human consumption, the present results pointed out that in both species Pb content was on average higher than the French limits, whereas the Cd and Hg contents were much lower than the same legislation limits