Trace metals in Posidonia oceanica in a coastal area of the Ionian Sea (Calabria, Italy)

As, Cd, Cu and Pb concentrations were meas- ured in Posidonia oceanica sampled from mea- dows located in two sites along the calabrian coast (Ionian Sea, South-eastern Mediterranean). By dating the scales and the rhizome using ret- rospective procedures (lepidochronology), a time series over a period of nine years (1995- 2004) was analysed. Throughout the whole lepi- dochronological period, the arsenic content in the scales was tenfold higher than that meas- ured in the rhizome with a peak in the lepido- chronological year 1996-1997 and a general de- crease in the years after. Pb concentration also showed a tendency to decrease with time, whe- reas the Cd and Cu concentration were in- creasing. A comparison of the metal level in dead sheaths (scales) and living tissue (leaves) was also performed. The detailed distribution of the trace metals along the leaf axis and in the leaves at different developmental stages (adult, intermediate and juvenile) showed some differ- ences in the metal content. The results also in- dicate that the arsenic content measured in the leaf blade reflects the high As content measured at the superficial sediments at one of the two sampled sites, demonstrating, for the first time, that P. oceanica would be a good indicator for this element.