Interaction of Microplastic Presence and Oxidative Stress in Freshwater Fish: A Regional Scale Research, East Anatolia of Türkiye (Erzurum & Erzincan & Bingöl)

The presence of microplastic (MP) in different fish species taken from stations in Erzurum, Erzincan and Bingöl was examined. The obtained data were classified and shared with the scientific world as the first record made in this region. In the obtained results, the most dominant color was black (39–58%) and the most prevalent forms were fragment and fiber. The sizes (0–50, 50–100 µm) of microplastics differed according to the region and species. When the number of MPs in the gastrointestinal systems of different fish species in the Bingöl, Erzurum and Erzincan provinces was evaluated, the most microplastics were found in Squalius squalus (20.7%) and Blicca bjoerkna (18.2%) in Bingöl province from among six different species. In Erzincan province, four fish species were sampled, and the rates were (29.7%) in Capoeta umbla and (26.6%) in Blicca bjoerkna . The highest abundance in Erzurum province was determined in Cyprinus carpio (53.0%). In the analyses performed on liver tissues, the highest ROS, which is the indicator of oxidative damage, was listed as Bingöl > Erzincan > Erzurum, while MDA levels were recorded as Bingöl > Erzurum > Erzincan, from high to low. When the differences between species were examined, the highest SOD and CAT activity was determined in the Mugil cephalus species. Considering the total MP numbers in fish samples, 47 MP was determined in this species. On the other hand, in the Squalius squalus species, where the highest total MP was determined, SOD and CAT activities were found to be low in Bingöl province. Therewithal, the high levels of ROS and MDA in this species can be said to induce oxidative stress due to the presence of microplastics on the one hand and to reduce antioxidant levels on the other hand. When the findings were evaluated, it was concluded that MPs in freshwater are a potential stressor, and freshwater environments may represent a critical target habitat for future MP removal and remediation strategies.