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.

The presence of microplastics (MPs) in several components of different ecosystems has aroused great concern and led to numerous studies on MP pollution. Although there has been an increasing number of these studies in aquatic ecosystems, no data about the MP pollution in zebra mussel (Dreissena polymorpha, Pallas 1771) living in Beyhan dam lake (Elazığ, Türkiye) are available. This study aimed to investigate the presence of MPs in freshwater mussel species found in this water reservoir. The distribution and characterization of MPs were investigated by Fourier transform infrared spectroscopy (FTIR) in zebra mussel (D. polymorpha) samples at four different stations. A significant difference in the MP presence between the 1st and 4th stations was observed (p < 0.05). A total of 52 MPs were determined in mussels collected from different stations in Beyhan Dam Lake. A total of 18 MPs of this total (1.80 ± 0.92 MP/individual) were obtained in station 1 and 7 of them (0.70 ± 0.82 MP/individual) were from the 4th station. Results of the MP investigation showed that the dominant color was black, the common size range was 1001–2000 µm, the dominant polymer shape was fiber, and the main polymer type was polypropylene (PP). A positive correlation was found among total MP and factors (length, tissue weight, and MP/individual). The detection of MPs in a freshwater mussel of the Beyhan dam lake can be suggested as a threat indicator and offers the possibility of using D. polymorpha as a bioindicator in the aquatic ecosystems’ MP pollution.

In recent years, with the encouragement of national and international authorities, researchers on plastic levels in aquaculture have begun to assess consumer health risks as well as ecological monitoring. Based on this guidance, the aim of this study is to determine the microplastic load of rainbow trout raised under routine breeding conditions without an external treatment in all developmental stages from egg to +1 year of age. Sperm, egg, fertilized egg, eyed egg, alevin or such fry, and swimming fry on growing stock (1-year-old) stages of cultured fish and commercial feeds were used for the following stages: 300–500 µm, 500–800 µm, 800–1200 µm, 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm. The samples were collected to determine the presence of microplastic (MP) and at which stage of this life cycle the MP has entered into the system intensively. The obtained findings showed that the total amount of MP determined in the stages without feed intake was 14 pieces, and this value increased by 557% (total of 92-piece MP) in fish that started external feeding. While no significant difference was found between the MP amounts in different feed groups, the dominant microplastic color in the feed groups was black and blue, and the polymer type was polyethylene. This general modelling, in which MP concentrations are determined in all life cycles from egg to adult in a cultured fish species, including in the given feeds, will encourage further research. Current findings have shown that any outsourced input used during growing periods can cause MP contamination to the end of fish production, processing, and storage.