Researchers have recorded microplastics in frog tadpoles and their pond habitats in the wild in the Amazon for the first time, according to a new study. This confirms widespread microplastic contamination in the Amazon Rainforest, the researchers say.
Previous studies from the region have found microplastic contamination in fish, invertebrates, soil and water samples.
In the recent study, ecologist Fabrielle Barbosa de Araújo from the Federal University of Pará and her colleagues collected 20 water samples from five natural water bodies formed by the accumulation of rainwater in soil depressions at Gunma Ecological Park in Pará state in April 2025. These temporary ponds are important breeding sites and larval development areas for various frog species in the Amazon.
From each of the five ponds, the researchers also collected 100 tadpoles of the Venezuela snouted treefrog (Scinax x-signatus), commonly found in both forests and urban areas across South America.
The researchers found microplastics in each sampled pond and tadpole. Most of the microplastics were transparent, blue and black fibers made of plastic like polyester. Other studies have also found similar blue and transparent fibers across the Amazon, possibly originating from sanitary sewage and fishing activities, the researchers write.
Araújo told Mongabay by email that finding microplastics in the tadpoles and their habitats was not surprising as several previous studies have shown microplastic contamination in other organisms in the Amazon. “What really caught our attention was the large quantity found, especially because this is an area with low [human] population density and considered relatively well preserved,” she said.
Araújo said she’s particularly concerned about microplastics in the tadpoles because the “contamination can negatively affect the health of amphibians, causing genetic and morphological damage, such as alterations in blood cells and in the DNA itself.” She added that microplastic particles can also accumulate in tissues and cause physiological changes in frogs.
The authors write that tadpoles of the Venezuela snouted treefrog eat algae, fungi and eggs in water and may have ingested the microplastics that way.
“Research on the presence of microplastics in the Amazon has intensified in recent years, and our goal is to continue monitoring this contamination, especially in anuran tadpoles, in order to better understand how this pollutant is affecting the biodiversity of our region,” Araújo said.
“This study provides the first evidence that microplastics are reaching tadpoles in the Amazon, a region where we have very limited data,” Jess Hua, an ecologist who studies freshwater ecology and amphibians and wasn’t affiliated with the study, told Mongabay by email. “This is important because amphibians represent the most threatened vertebrate taxa and understanding potential threats, including from microplastics, is important to their conservation.”
Hua added that microplastic contamination in freshwater systems is still much less studied compared to marine systems.
Banner image of a Venezuela snouted treefrog by Taucce et al., 2022, via Wikimedia Commons (CC BY 4.0).
