Microplastic pollution in UNESCO world natural heritage sites: A global integrative review

Microplastic (MP) pollution has emerged as a primary threat to aquatic and terrestrial ecosystems, including globally recognized protected areas. This review critically evaluates the presence, distribution, and impacts of MPs in regions classified as UNESCO World Natural Heritage Sites. The analysis encompasses 60 studies published up to December 2024, highlighting temporal trends and geographic gaps. Findings reveal that of the 312 UNESCO-recognized areas, only 28 have been the focus of MP-related studies, primarily in coastal and aquatic ecosystems. Notable sites include the Galápagos Islands, the Great Barrier Reef, and the Fernando de Noronha Archipelago. MPs, predominantly synthetic fibers composed of polyethylene (PE) and polypropylene (PP), were detected across various environmental matrices and organisms, including sediments, surface waters, and marine and freshwater species. Furthermore, human activities such as unregulated tourism and improper waste disposal exacerbate the dispersion of MPs, compromising the ecological integrity of these regions. This review identifies methodological gaps and proposes more integrated approaches to enhance monitoring and mitigation efforts, emphasizing the importance of global and regional public policies. By contributing to a broader understanding of MPs’ impacts in areas of high ecological and cultural value, this study highlights the need for coordinated actions that balance environmental conservation with economic sustainability.