Avaliação de microplásticos em lixiviado de aterro sanitário

Abstract

Microplastics (MPs) are plastic particles ranging in size from 0.001 to 5 mm, whose presence in the environment has raised increasing concern due to potential risks to biota and human health. Despite advances in research in aquatic environments, the occurrence and characterization of MPs in landfill leachates remain scarcely explored in Brazil. In this context, the aim of this study was to identify and characterize MPs present in raw leachate samples from a landfill located in the municipality of São Leopoldo – RS. Three sampling campaigns were conducted throughout 2024. The samples underwent sieving, oxidative treatment with Fenton’s reagent, vacuum filtration, and subsequently, suspected particles were confirmed as MPs by Raman spectroscopy. Only after this chemical confirmation were the particles physically characterized in terms of morphology, shape, color, and size. Concentrations ranged from 13 to 73 items/L. Polypropylene (PP) and polyethylene (PE) polymers predominated, together representing the majority (80%) of identified MPs. Fragment-type particles were predominant (98%), indicating a secondary origin, i.e., derived from the fragmentation of plastic waste disposed of in the landfill. Most particles were smaller than 75 µm, suggesting high mobility and potential for percolation in the environment. MP abundance correlated with leachate physicochemical variables, such as turbidity, organic load, and color, as well as environmental factors, including temperature and precipitation. The results indicate that landfills may act as significant sources of MPs. This study helps fill knowledge gaps on the topic in Brazil and may support environmental education initiatives and the development of strategies to mitigate plastic pollution.