Investigation of Microplastic Pollution in the Sediment and Commercial Fish Species of Gemlik Bay (Marmara Sea) by Microscopic and Spectroscopic Methods

Abstract Currently, the microplastic pollution is a common phenomenon in the wold wide. Microplastic density has enhanced and accumulated over decades in the aquatic ecosystems and caused many physiological problems in living organisms. Also, toxicity of microplastics increases by providing a surface area to the other polutants. In this study, we aimed to evaluate and characterize the microplastic pollution in the sediment and commercial fish species in the Gemlik Bay, Marmara Sea. Our results showed that the highest accumulation of microplastics in the sediment is at the station in the Gemport Harbor (9733.3 pieces.kg -1 ) and the lowest accumulation is at the Kurşunlu offshore (3333.3 pieces.kg -1 ). On the other hand, the highest microplastic accumulation per individual was in the gills of Synapturichthys kleinii (Risso, 1827) (14.5 pieces.ind -1 ) and the lowest in Diplodus annularis (Linnaeus, 1758) (0.33 pieces.ind -1 ). The highest accumulation was indicated (8.75 pieces.ind -1 ) in the gastrointestinal tract of Chelidonichthys lucerna (Linnaeus, 1758), but the lowest accumulation is in that of D. annularis (0.88 pieces.ind -1 ) species. The fiber-type particles were the most determined microplastics in sediment and fish samples. Micro-Raman Spectrometer was revealed that Polyvinyl chloride (PVC) and polypropylene (PP) were dominant in the sediment, and polyoxymethylene (POM) and polyphenylene sulfone (PPSU) polymers were dominant in fish species. Our study showed that more intense microplastic pollution were determined in the Gemlik Bay then the other locations of Marmara Sea. Also our results suggested that there was a pollution pressure on the ecosystem and that the requirement of controlling the ports and discharge waters underlined.