The impact of sediment dumping sites on the concentrations of microplastic in the inner continental shelf of Rio de Janeiro/Brazil

The marine environment is constantly being impacted by anthropogenic activities. Nowadays, microplastics (MPs) representing one of the most deleterious material among of all substances and material from anthropogenic origin. The Microplastics (MPs) are particles smaller than 5 mm. This study presents information on abundance, distribution, type and colour of microplastics in the bottom sediments of the continental Shelf of Rio de Janeiro State. This area is strongly impacted due to its location in front of one of the most polluted coastal bays in the Brazilian Coastline. It receives untreated sewage from an Ipanema Beach submarine emissary and also a great amount of sediments dredged from Rio de Janeiro Harbour, which strongly influences the distribution of MPs in the area. The analyses detected the presence of MP in 100% of the samples, composed mainly by secondary microplastics, and almost 50% were fibers, followed by plastic films, plastic fragments and pellets. Based on the nature of the sources of the MP, a great variety of colours was shown, dominated by four main colours: blue, white, transparent, and black, this pattern could potentially increase their bioavailability due to resemblance to prey items, especially to visual raptorial species. •Microplastic pollution in Rio de Janeiro Continental Shelf•Concentrations and distribution of microplastic in the bottom sediment of Rio de Janeiro Continental Shelf•Type and colour of microplastic in the bottom sediment of Rio de Janeiro Continental Shelf•The impact of dumping sites in the concentrations of microplastic in the bottom sediment of Rio de Janeiro Continental Shelf