Microplastic pollution in bivalve species from tropical mangrove habitats

Abstract

The presence of microplastics (MPs) in three bivalve species used for human consumption was assessed. Bivalves were collected from a mangrove of the most densely populated city in Brazil. The results revealed that 63 % of bivalves were contaminated, with density of 0.85 ± 0.13MPs.ind⁻¹ and 0.80 ± 2.2MPs.g⁻¹ww. Particles were mainly classified as fibers and films, with sizes ranging from 103 µm to 4994 µm. Our findings suggest that infaunal species ingest microplastics of higher density than the sessile oyster. Polymer identification revealed the presence of polyethylene terephthalate, polypropylene, polyethylene, and polycarbonate. Finally, we detected a lack of seasonal variation in the MPs, indicating a regular urban-derived source of MPs, with constant outflow from wastewater over the year. Our new results highlight the importance of studies in highly-urbanized mangroves in the Global South due to the scarcity of problem-based research and the fact that these estuaries are hotspots for MPs worldwide.