Microplastic pollution of the beaches of Guanabara Bay, Southeast Brazil

• An analysis of microplastic pollution of the beaches of Guanabara Bay in southeastern Brazil was carried out.
• Concentrations and distributions of microplastic on beaches were described.
• Environmental consequences of microplastic in the coastal area were discussed.
• Our analyses showed that there were differences between the seasons in the concentrations of microplastic in Guanabara Bay.

Plastic debris is widely recognized as an important marine environmental pollutant. Plastics pollution of coastal areas is a growing concern, with research efforts focusing on macroplastic (>5 mm) and microplastic fractions. Currently, a large proportion of the plastics found in the ocean are in the form of microplastics (<5 mm). Due to their buoyant and persistent properties, microplastics have the potential to be widely dispersed via hydrodynamic processes and ocean currents. Guanabara Bay has been identified as one of the most polluted environments on the Brazilian coastline, mainly due to the presence of heavy metals and hydrocarbons. The aim of this work was to investigate, using field surveys, the abundance, composition and distribution of microplastics and small plastic fragments on the beaches of Guanabara Bay, located in southeastern Brazil. Microplastic concentrations ranged from 12 to 1300 particles per m2on the beaches. Fibres, fragments, styrofoam and pellets accounted for 8766 particles, with microplastic fragments representing 56% of the total detected debris, followed by styrofoam fragments (26.7%), pellets (9.9%) and fibres (7.2%).