Evolution of potential ecological impacts of the bottom sediment from the Gulf of Gemlik; Marmara Sea, Turkey.

The eastern and southern coasts of the Gulf of Gemlik, a resort in the Sea of Marmara, Turkey, are under the influence of rapid ecotourism development, direct domestic and industrial discharges via rivers and outfalls, surface run-off, drainage from ports and shipping. According to sediment quality criteria in use around the world, sediment quality in the gulf shows a broad spectrum. It is more related by direct input, rather than by the type of sediment, and excluding inner port and southern coasts, it does not exert adverse biological effects yet. The total PAH concentrations range from 51 to 13,482 ng/g dry weight with the mean value of 1,850 ng/g dry weight (n = 61). The elevated values of the total toxic Benzo[a]pyrene equivalency (TEQcarc), with a maximum of 1,838 ng/g dry weight, were found at the inner harbor of Gemlik, possibly posing hazard to benthic organisms. Among the different PAHs, the contribution to the total TEQcarc decreased as the following order: Benzo[a]pyrene (43.6%) > Benzo[k]fluoranthene (36.0%) > Indeno[1,2,3-cd]pyrene (35.1%) > Benzo[b]fluoranthene (20.0%) > Chrysene + Triphenylene (18.9%) > Benzo[a]anthracene (12.5%).