Microplastic contamination in tadpoles (Anura) in the Brazilian Amazon

The potential risks posed by microplastics (MPs) to anuran tadpoles remain poorly studied in the Brazilian Amazon region. Therefore, the aim of this study was to analyze MP contamination in Scinax x-signatus tadpoles at two developmental stages, as well as to characterize and quantify MPs. In addition, we evaluated MP concentrations in surface water and their relationship with environmental characteristics. The study was conducted at the Gunma Ecological Park, Santa Bárbara, Pará, Brazil, across five sampling sites during April 2025. We identified MP contamination in both surface water and tadpoles from all sampled sites. Environmental characteristics showed no direct relationship with MP contamination in tadpoles. However, tadpoles in the pre-metamorphic stage exhibited higher levels of MP contamination than those in the pro-metamorphic stage. A correlation was observed between tadpole body weight (g) and MP concentration, indicating that MP ingestion decreased as body weight increased. This study is the first to report in situ MP contamination in anuran tadpoles from the Amazon region, demonstrating the susceptibility of these organisms to contamination by this pollutant.