NACREOUS SHELL OF MYTILUS-GALLOPROVINCIALIS AS A BIOMONITOR OF HEAVY-METAL POLLUTION IN GALIZA (NW SPAIN)

The rock mussel (Mytilus galloprovincialis Lam.) was used as a biomoni tor species for metal pollution on the coast of Galiza, NW Spain. The measured concentrations in the soft tissues and in the nacreous shell were contrasted with those from the HCl and HNO3 leached fractions of sediment samples collected from the mussels' environment. The nickel a nd lead concentrations in the nacreous shell and the zinc and lead con centrations in the soft tissues were correlated with the sediment meta l levels. The results suggest that Mytilus galloprovincialis can be us ed as a particularly appropriate biomonitor for lead pollution, with t he nacreous shell seemingly producing better results than the tissue.