Ingestão de microplásticos por diferentes guildas tróficas em um reservatório tropical

Abstract

Microplastic pollution has emerged as a significant threat to continental aquatic ecosystems, particularly in tropical reservoirs, where substantial knowledge gaps remain. This study assessed microplastic ingestion by fish belonging to different trophic guilds in the Furnas Hydroelectric Reservoir, Minas Gerais, Brazil, investigating patterns of abundance, composition, and associated ecological drivers. A total of 180 individuals representing nine species distributed among piscivorous, invertivorous, omnivorous, detritivorous, and herbivorous guilds were analyzed. Stomach contents were subjected to chemical digestion using hydrogen peroxide, followed by filtration and stereomicroscopic analysis, with particles classified according to type and color. A representative subsample was analyzed using Raman spectroscopy for polymer identification. The results revealed significant differences in microplastic ingestion among trophic guilds, with higher abundances observed in invertivorous species, highlighting the influence of feeding behavior and habitat use on contaminant exposure. Fragments and fibers were the predominant particle categories, mainly black and transparent, suggesting multiple contamination sources and high bioavailability. Raman spectroscopy confirmed the predominance of polyethylene terephthalate, followed by polystyrene and polypropylene, as well as the presence of associated pigments. These findings reinforce the role of tropical reservoirs as important microplastic retention zones and emphasize the relevance of trophic guilds as predictors of susceptibility to ingestion, contributing to the understanding of ecological mechanisms underlying microplastic contamination and supporting the development of monitoring and mitigation strategies in freshwater ecosystems. Keywords: Plastic debris; Raman spectroscopy; Polyethylene terephthalate; Environmental contamination.