Microplastic Uptake in Fishes from Crișul Repede River (Bihor County, Romania): A Preliminary Study

Microplastic (MP) pollution in freshwater is an important global issue affecting an increasing number of areas. MP is ingested by aquatic organisms and transferred through food chains, causing impacts on both aquatic life and human health. While studies on MP uptake in the gastrointestinal tract (GIT) of fish are numerous globally, in Romania, there are extremely few. As a result, we conducted research on this phenomenon in fish species from the Crișul Repede River (CR) in two river sectors with different levels of anthropogenic impact. We found out that 100% of the collected fish had MPs in their GIT, with most of the particles being small-sized fragments (0.025–0.1 mm). Upstream, benthopelagic species ingested more MPs than downstream, whereas for benthic species, the amount of MPs in the GIT was greater downstream. Larger individuals contained more MPs than smaller ones. The presence of MPs in fish bodies can pose a problem if these particles enter internal organs and trigger adverse physiological effects.