The content of several heavy metals (As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn) was determined in
sediments and in plants (the halophytes Sarcocornia fruticosa and Limonium vulgare) from two selected
saltmarshes located in the Marano and Grado Lagoon (Northern Adriatic Sea). This environment has been
affected by severe Hg contamination from both industrial and long-term mining activities. In both saltmarshes,
Hg content in sediments exceeded the estimated background value (0.13 μg g-1), showing the highest
concentrations (13.7 μg g-1) in the eastern sector (Grado Lagoon), the most affected by cinnabar ore extraction.
On the other hand, the saltmarsh, located in the Marano Lagoon, showed a higher degree of contamination for
As, Cd and Pb, which can be related to industrial sources. The rhizo-sediments of both halophytes reflected
the characteristics of the non-vegetated sediment, with higher organic carbon content and similar metal
concentrations. Enrichment Factors (EF=[metal]root/[metal]rhizo-sediment) for each sediment layer were calculated
for both halophytes, showing metal enrichments in the roots and the presence of preferential layers of metal
accumulation. Hg showed accumulation (EF>1) in the roots below the 20 cm depth, with higher contents in S.
Fruticosa. As and Cd were accumulated by both halophytes, more efficiently by S. Fruticosa, and the same
species showed also accumulation of Pb and Zn. Translocation of metals from the roots to the aboveground
biomass was investigated by measuring metal contents in shoots and leaves of the two species. With the
exception of Cd and Hg, all metals were present in the aboveground biomass, most evidently for Cr in S.
Fruticosa and Zn in L. Vulgare, although the presence of the latter in leaves could be due to plant physiology
rather than translocation of the contaminant.
