Distribution And Association Of Trace Metals In Soft Tissue And Byssus Of Mytilus Edulis From The East Coast Of Kyushu Island, Japan

Abstract. Concentrations of Cd, Pb, Zn, Cu, Ag, Cr, Co Ni, Mn, and Fe in soft tissues 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 soft tissues and byssi (Cu, Cd, and Pb and Cu, Pb, Co, Ni, Mn, and Fe, respectively) 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 contaminated locations compared to those from a nonindustrialized area. Intercomparison of the present study data with those published previously indicates that the soft tissue and especially byssus are useful in detecting some areas of some metallic contaminants. The high concentrations of Cd, and especially Pb and Cu, in Saganoseki mussels and moderately elevated concentrations of these metals in Akamizu mussels may be attributed to the anthropogenic emissions from a metallic refinery and an artificial fiber factory, respectively. It is evident that, compared to the soft tissue, the increase of Cu levels relative to Zn levels 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 byssus, 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.