A New Assessment of Heavy Metal Contaminations in an Eutrophicated Bay (Inner Izmir Bay, Turkey)

The distribution, controlling geochemical factors and contamination status of heavy metals in inner Izmir Bay (Eastern part of Aegean Sea) were investigated. 23 surface sediment samples were collected and analized for major elements (Al and Fe), heavy metals (Pb, Zn, Cd, Cu, Hg, Cr, Mn), organic matter, grain size composition, carbonate and Chl.-a. Metals controlling factors were elucidated based on statistical methods such as the Pearson product-moment linear correlation and Factor Analysis. The results illustrated that Pb, Zn, Cr and Cd are mainly controlled by organic matter and a lesser extent Fe. Pb also controlled by carbonate and Mn additionally. Other controlling factor on Cr and Cd are Chl.-a via uptake in water column and then sedimentation. Cu and Hg are mainly controlled by Chl.-a. Some evidences were found on changing of carrier phases. The results indicated that contamination of surface sediments in inner Izmir Bay is dominated Pb, Hg, Cd, Zn and to a lesser extent Mn, Cu, Cr and Fe. Igeo classification was consistent with the Enrichment Factor ans Contamination Factor classes generally. Geoaccumulation index values for Zn, Hg, Cr and Cd have decreased two contamination classes from 1994 to 2008, whereas Pb has remained the same and Cu has decreased only one class. Generally Cu, Zn, Pb, Hg and Cr contaminations were below effects range median values. The extent of heavy metal contamination and degree have been affected significantly by sedimentological parameters such as grain size, organic carbon, carbonate and chloropyll-a.