Bioindicator organisms: heavy metal pollution evaluation in the Ionian Sea (Mediterranean Sea--Italy).

Trace metal concentrations of mercury, cadmium, lead and chromium in Patella caerulea, and Mullus barbatus were investigated to provide information on pollution of Ionian Sea, since these metals have the highest toxic potential. High chromium levels (0.47-0.97 microg g(-1) ww) were registered in limpet samples collected from two station near the Gulf of Taranto, while elevated concentration of mercury (0.31-1.50 microg g(-1) ww) were found in mullet specimens from Sicily. The metal concentrations recorded at the clean stations may be considered as useful background levels to which to refer for comparison within the Mediterranean area. On the contrary, the high levels of chromium and mercury found respectively in the areas near the Gulf of Taranto and at Capo Passero being of concern in terms of environmental health need frequent monitoring.