A new record for the presence of microplastics in dominant fish species of the Karasu River Erzurum, Turkey

It is known that microplastics (MPs) are increasingly detected in aquatic environments (sea and fresh water), and the presence of these pollutants have worrying potential effects on the biota. This study is the first research to measure and characterize MPs in freshwater ecosystems (inland waters) in Turkey. Accordingly, the identification and characterization of MPs in the gastrointestinal systems of fish by making samples of three species [chub (Squalius cephalus), common carp (Cyprinus carpio), and mossul bleak (Alburnus mossulensis)] of the carp family living in Karasu River in Erzurum. Hydrogen peroxide application and Fourier transform infrared-attenuated total reflectance (ATR-FTIR) analyses were done for this purpose. In the obtained results, 232 microplastics were found in all three fish gastrointestinal systems. While the highest determined color was black (39-58%), the most common shape was fiber (88%), fragment (6%, and pellet (6%); MPs in the range of maximum 1001-2000 mm were detected in size. Plastics are defined as polyethylene, polyester, poly (vinyl stearate), polyethylene terephthalate, polypropylene, and cellulose. Among the studied species, the most common type of plastic pollutants was found in S. cephalus. The findings indicated the presence of microplastics in dominant species. However, these findings will be basic information for future studies on living things and microplastics in inland waters.