Screening for Microplastic Uptake in an Urbanized Freshwater Ecosystem: Chondrostoma nasus (Linnaeus, 1758) Case Study

The feeding characteristics of the nase, based on its mouth morphology and feeding behavior related to aquatic habitat substrata sediments make this fish a biological uptake vector for microplastics in freshwater ecosystems. Fibers may have limited absorption through the gastrointestinal tract therefore unlikely to be found in fish gastrointestinal tissue and muscle tissue. The presence of microplastic fibers in the gastrointestinal content is proof of how difficult it is for these fibers to become embedded in other organs. The absence of microplastic fibers in muscle tissue and gastrointestinal tissue is key information for microplastic fabrication and management in aquatic ecosystems. The majority of fish have relatively low levels of microplastics; however, a few individuals have a higher dose. This is true for all types of microplastics analyzed, with the exception of fish that had just one microplastic present in the analyzed matrix. The microplastics are not concentrated in the fish muscle tissue, gastrointestinal tissue and gastrointestinal content in relation to fish age, which may be due to their different mobility in the ecosystem, or due to the recent appearance of this type of contamination and the scale at which microplastics bioaccumulate. Such a relatively common fish species must be included in the assessment and monitoring systems of the Eurasian lotic systems. The risks involved include the transfer of the freshwater environments microplastics into human tissues via the food web of fishing species with the nase as a key basis.