Plastic pollution in the Amazon: The first comprehensive and structured scoping review

Plastic pollution is a global One Health crisis, yet research has focused largely on marine environments. The Amazon-the world's largest drainage basin and second most plastic-polluted river-has received limited scientific attention. This scoping review is the first to apply a systematic protocol (PRISMA-ScR) to assess plastic contamination across Amazonian ecosystems. We reviewed 52 peer-reviewed studies reporting plastic litter and fragments in terrestrial and aquatic environments of the biome. Most evidence concerns microplastics in Brazilian sites along the main Amazon River, with a focus on fish. However, plastics were also found in sediments, plants, and diverse fauna including birds, reptiles, and mammals. No studies reported nanoplastics. The contamination of key food and water sources poses a major One Health risk for traditional populations. We identify urgent research gaps-especially in non-fish fauna, tributaries, and other Amazonian countries-and highlight the need for targeted mitigation through waste management and education.