Pollution and toxicity of sediment in potential dredging sites of the Marmara Sea, Turkey

Abstract

This study aims to assess the impact of the sediment in the potential dredging areas of the Marmara Sea. To that aim, sediments were analyzed for polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and heavy metals, sources were discussed, and toxicity tests were applied. For assessment, lower and upper limits of Turkish draft regulation (LTR, UTR) and UNEP-MAP's guidance document (LCT, UCT), and effects range low and median (ERL, ERM) were used. Total concentrations were found between 562 and 8643 µg kg-1 for PAHs, 4-36 µg kg-1 for PCBs, and 14-190 µg kg-1 for OCPs. The highest ∑PAH concentrations were measured in Golden Horn, and none of the PAH compounds was above ERM. ERL and UCT were exceeded in İstinye and Golden Horn stations. The highest ∑PCBs and ∑OCPs levels were determined in İzmit Bay (IB). ΣPCBs in IB were higher than ERL and LTR, while ΣDDT were found above ERM and UCT. High concentrations of chromium (∼190 mg kg-1) and copper (∼180 mg kg-1) in Golden Horn and mercury in IB (∼4 mg kg-1) were detected. The highest toxicities were observed in İstinye and İzmit Bay. According to the regulations, none of the sediments can be dumped.