The fauna and toxicological evaluation of marine sewage outfalls

With this study, the fauna of Rize, Pazar and Yalova marine sewage outfalls were determined, the relationships with the ecological environment and the effects of pollutants were discussed together. In this study conducted between April 2018 and April 2019, video survey method and underwater visual census were used seasonally to determine the faunistic characteristics of marine sewage outfalls. As a result of the sampling, 9826+ individuals belonging to 6 classes and 23 families belonging to a total of 25 species were observed. Sediment samples were taken to determine the benthic organisms and a total of 1625 individuals/m2 were obtained from 11 species from 9 families. In addition, surface sediment samples were taken to analyze the pollutants carried by the deep sea discharge system and to determine their toxic effects. Heavy metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) were investigated in the sediments to determine pollution degree. Stations of Yalova (S5, S6) were classified as having high contamination levels (1034.436 and 1476.483 ng/g, respectively) and all the other stations suffered moderate pollution in terms of Σ16PAHs. ΣDTT level in sediments of Yalova and Rize stations were determined above Probable Effect Levels (PELs). The highest metal concentrations ranged from 4,97 to 29,65 mg/kg for Ni; 7,57–44,14 mg/kg for Cr; 9,84–42,76 mg/kg for Cu and 48,08–103,77 mg/kg for Zn. In addition, the "Whole Sediment Toxicity Test" was carried out on sediment samples and the survival rates of amphipod E. olivii were determined between 26,67 ± 7,64 and 88,33 ± 2,89 as a result of the test.