Microplastic ingestion by Characidae in rural streams (Rio Grande do Sul, Brazil)

Microplastics (MP) have several negative effects on biodiversity, from the ecosystem to individual levels, and can be easily consumed by small invertebrates and fish. The increased production of plastic and absence of efficient management systems for these residues facilitate their presence in aquatic environments. In this study, we evaluated the presence of MP in the stomach contents of four species of Characidae in rural streams in the upper portion of the Uruguay River watershed (northern Rio Grande do Sul). Among the total of collected organisms (n=121), the presence of MP was observed in 72% of the analyzed stomach contents. Bryconamericus iheringii had the highest occurrence of MP (85.7%), followed by Astyanax lacustris (69.4%), Astyanax henseli (69.1%) and Oligosarchus breviostris (66.7%). Our results demonstrate the high occurrence of MP in freshwater aquatic environments, especially rural streams. The results observed in this study confirm the importance of conservation of streams, from the maintenance of riparian vegetation as a way to reduce the input of MP in these ecosystems.