| Popis: |
Eight sediment cores from the coastal marine area of the western Saronikos Gulf have been analysed for grain size and geochemistry. The concentrations of eight metals (Al, Fe, Mn, Cu, Cr, Ni, Pb and Zn) were measured along with total organic carbon (TOC) and carbonate content. The cores are fairly homogeneous in terms of carbonates and the downcore variability of TOC percentage (% TOC) and are characterized by high surficial values that decrease with depth. Metal concentrations from both geological (Al, Mn, Cr, Ni) and anthropogenic origin (Cu, Pb, Zn) are higher in the muddy fraction than in the sand fraction of sediments. The spatial distribution of Al, Fe, Mn, Cu, Pb and Zn in surface sediments presents increasing concentrations from the northeast to the southwest part of the study area and from the shallow to the deeper parts in contrast to Cr and Ni, which are increased in the northern nearshore stations. Based on the vertical distributions, the metal to Al ratios of Cu, Pb and Zn show a constant decrease over depth along most cores, indicating the anthropogenic effects to surface sediments, while Fe/Al is constant. Spearman's correlation analysis performed among the fine-grain metal contents demonstrated a strong positive correlation (r>0.5, p |
