RESUMO
Concentrations of Al, V, Mn, Fe, Co, Cu, Ni, Zn, Sr, Mo, Cd, Sb, Pb, Th, U, REE, Na, K, Mg, Ca, Si, P, S, Ti, Cr and Ba were determined in the <63 microm fraction of bottom sediments of the Szczecin Lagoon and the Gdansk Basin, Baltic Sea, by ICP-MS, ICP-AES and XRF methods. Sediment samples from the Szczecin Lagoon displayed somewhat higher concentrations of P, Mn, Cr, Cu and possibly Cd, Pb and Zn in those collected in October 1997 after the exceptional flooding of the Oder River than in those collected in December 2000. The data suggest that the flood resulted in the enhanced transport of redox-sensitive and anthropogenic elements in the Oder River and their subsequent redeposition mainly in the western part of Szczecin Lagoon. The sediments of the Szczecin Lagoon also appear to be the most polluted with heavy metals within the Polish Exclusive Economic Zone (EEZ) of the Baltic Sea. Cd, Pb, Zn and Cu are anthropogenically enriched in top layers of sediment cores from the Gdansk Basin, but the decrease of these elements with depth in the core is not systematic. The rare earth element (REE) patterns in sediments from both these areas do not appear to have been greatly modified during transport from their source into the southern Baltic. Factor analysis (FA) of the compositional data shows that sediments from Szczecin Lagoon can be divided into three main groups depending on their composition. It is concluded that clay minerals and organic matter build aggregates and flocs, which effectively concentrate trace metals and sink down to form a 'fluffy layer'.
RESUMO
Concentrations of Hg, Cd, Pb, Ag, Cu, Zn, Cr, Ni, Co, Mn, and Fe in soft tissues, shells and byssus of blue mussel (Mytilus edulis trossulus) from 23 sites along the Polish coast of the Baltic Sea were determined by AAS method. Byssus, as compared with the soft tissue, concentrated more effectively Pb, Cu, Cr, and especially Ag, Ni, Mn and Fe, moderately Hg and Zn and less effectively Cd. Significant inter-regional and inter-size differences in metal concentrations in both soft tissues and byssus were recorded. Highly significant correlations (P<0.01, P<0.05) were observed between tissue and byssal concentrations of Cd, Pb, Ni and Ag. Factor analysis showed clear separation of both the tissue and byssi samples based on their geographic distribution, possibly reflecting a different rate of deposition of clay minerals at the head of the Pomeranian Bay and the Gulf of Gdansk. The Pomeranian Bay differs from the Gulf of Gdansk in respect to geological structure of bottom sediments as a substrata for the M. edulis trossulus as well as in relation to various sources of metallic pollutants. From the data obtained in the present study and those reported previously the soft tissue and especially byssus of M. edulis, in contrast to shells, appear to be a significantly better bioindicator for identification of coastal areas exposed to metallic contaminants.
