Plastic particles in three Brazilian Federal Conservation Units: are aquatic matrices really protected?

This study investigated, for the first time, plastic particle contamination in abiotic and biotic matrices of three Brazilian Federal Conservation Units. We analyzed small freshwater bodies (lagoons and puddles), characterizing the abundance, size, shape, and color of plastic particles in three matrices: water, sediment, and tadpoles. Nine species of Neotropical anuran tadpoles were examined. Microplastic particles were identified based on visual criteria under optical microscopy. Plastic particles were detected in all matrices, with varying abundances. Both microplastics (MPs) and mesoplastics were observed, with MPs < 0.5 mm predominating, mainly in the form of blue fibers. Five tadpole species showed MP contamination: Dendropsophus novaisi, Scinax pachycrus, Leptodactylus caatingae, Leptodactylus macrosternum, and Physalaemus cuvieri, with no mesoplastics detected in tadpoles. The results indicate considerable, though not extreme, exposure to plastic particles, likely associated with human sources adjacent to the protected areas. The presence of these particles even in legally protected environments highlights the silent threat of plastic pollution and the urgent need for effective public policies. This study contributes to the understanding of plastic particle contamination in freshwater ecosystems and their bioaccumulation in tadpoles, reinforcing the importance of sustainable management in these environments.