The Use of Zebra Mussel (Dreissena polymorpha) as a Sentinel Species for the Microplastic Pollution of Freshwater: The Case of Beyhan Dam Lake, Turkey

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.