Abstract
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.
Highlights
Saltmarshes are important constituents of transitional environments, where they provide several services to the ecosystem and are essential to the sedimentary budget (Pethick, 1984)
The content of several heavy metals (As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn) was determined in sediments and in plants from two selected saltmarshes located in the Marano and Grado Lagoon (Northern Adriatic Sea)
The heavy metal content in the sediments was quite high at both saltmarshes
Summary
Saltmarshes are important constituents of transitional environments, where they provide several services to the ecosystem and are essential to the sedimentary budget (Pethick, 1984). These peculiar environments are subject to the effects of increasing human pressure, especially where anthropogenic activities occur. Sediments trapped by the saltmarsh vegetation may be affected by the accumulation of several contaminants, heavy metals included (Cacador et al, 1996). A common characteristic is their ability to accumulate heavy metals both in roots and shoots (Cacador et al, 2009; Canario et al, 2010). In this manner, they act as hyper accumulators, providing a natural metal-extraction pathway for remediation activities
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
