DISTRIBUTION AND ASSOCIATION OF TRACE-METALS IN SOFT-TISSUE AND BYSSUS OF MYTILUS-EDULIS FROM THE EAST-COAST OF KYUSHU ISLAND, JAPAN

Concentrations of Cd, Pb, Zn, Cu, Ag, Cr, Co Ni, Mn, and Fe in soft ti ssues and byssi of blue mussel (Mytilus edulis) from three sites along the east coast of Kyushu Island, Japan, were determined by AAS method . Large inter-regional differences in metal concentrations in both sof t tissues and byssi (Cu, Cd, and Pb and Cu, Pb, Co, Ni, Mn, and Fe, re spectively) were recorded. Highly significant correlations (p < 0.01) were observed between tissue and byssal concentrations of Pb, Cu, Zn, and Mn. The tissue concentrations of Cu, Cd, and Pb were two orders of magnitude greater in Mytilus edulis from expected to be the most cont aminated locations compared to those from a nonindustrialized area. In tercomparison of the present study data with those published previousl y indicates that the soft tissue and especially byssus are useful in d etecting some areas of some metallic contaminants. The high concentrat ions of Cd, and especially Pb and Cu, in Saganoseki mussels and modera tely elevated concentrations of these metals in Akamizu mussels may be attributed to the anthropogenic emissions from a metallic refinery an d an artificial fiber factory, respectively. It is evident that, compa red to the soft tissue, the increase of Cu levels relative to Zn level s in the byssi of M. edulis are eight times higher, with a slope b (Cu /Zn) of 7.5 for byssus and 0.93 for soft tissue. This suggests that by ssus, as compared to soft tissue, is a more sensitive bioindicator for Cu. From the data obtained, the soft tissue and especially byssi of M . edulis appear to be good bioindicators for identification of coastal areas exposed to metallic contaminants.