Assessment of marine pollution in Izmir Bay: Heavy metal and organic compound concentrations in surficial sediments

The extent of marine pollution in Izmir Bay is investigated using inorganic and organic geochemical data from surface sediments. The concentrations of 42 elements in 84 samples established that surface sediments in Inner Izmir Bay display significant enrichments in Ag, As, Cd, Cr, Cu, Hg, Mo, P, Pb, Sb, Sn, V, and Zn, associated with notably high concentrations of total organic carbon and sulphur. Organic geochemical data in 14 samples from Inner Izmir Bay showed that these sediments also exhibit significant enrichments in polycyclic aromatic hydrocarbons and polychlorinated dibenzo-d-dioxins and dibenzofurans. Combined inorganic and organic geochemical data indicated that Inner Izmir Bay surface sediments are extremely polluted and probably pose high risk to the resident marine biological community. Except for a few small regions, the Outer and Central Izmir Bays show low levels of heavy metal enrichments. Moderate enrichments in Ag, Cd, Hg, Mo, Sb and Sn in surface sediments east of Hekim and Cicek Islands probably reflect continuous dumping of sediments excavated fromt he most polluted innermost Izmir Bay between 1976 and 1990. The zone of moderate enrichments in Cd, Cr, Cu, Hg, Pb and Zn south of the present-day mouth of Gediz River suggests that discharge from this river is one of the major sources of anthropogenic input into the Outer Izmir Bay and probably reflects the large quantities of industrial discharge into Gediz River along its course