Environmental assessment of heavy metal and organic matter contamination, related to anthropogenic production in Ildır Bay, Eastern Aegean Sea, Türkiye

Ildır Bay, a semi-enclosed bay in the Eastern part of the Aegean Sea, is important in many areas such as fishing, aquaculture and also tourism. Due to these activities, the ecosystem of the bay has been significantly affected anthropogenically. It is not known which activity affects how much the ecosystem. However, the rapid development in the field of aquaculture is remarkable. The main purpose of this study is to describe the organic carbon and heavy metal distribution in sediments of the bay and the changes in the ecological level especially those caused by domestic and aquaculture effluent.

Sediment samples were collected by Gramp Sampler in 2007 at surface and subsurface levels from nine stations in Ildır Bay and one in Gerence Bay. Organic carbon and selected heavy metals were analyzed. Results of analyses showed that the concentrations of some transitional metals (Mn, Ni, Zn, Hg, Cr) and Pb in the sub-surface layers were less compared with surface layers. Significant differences between surface and sub-surface sediments were observed regarding contamination with organic carbon. Differences were also observed all over the bay, ranging from 1.29 to 27.69 mg/g. In addition, metal/organic matter association decreased in comparison with the lower surface layers. Principal Component Analysis supports that a negative trend began in the marine sediment criteria in Ildır Bay.