The city of Rio de Janeiro, located on the southeastern coast of Brazil, has about 6.8 million
inhabitants and is one of the main economic, cultural, financial and tourist centers in the country. The
lack of adequate systems for the treatment of domestic and industrial effluents, the indiscriminate
release of solid waste and the large flow of visitors and tourists on the beaches of the city of Rio de
Janeiro make it an excellent object of study to assess the contamination status of beaches located in
large urban centers. This research aims to evaluate the abundance, distribution, quantification and
characterization of microplastics present on the beaches of the city of Rio de Janeito. 34 samples were
collected divided into 15 beaches. Initially, the organic matter was digested using 30% H2O2 and
then the microplastics were separated using a saturated NaCl solution (1.2 g/cm3). The separated
microplastics were examined under a microscope and classified according to length, color and shape
(fiber/film, shred, threads/fibers and styrofoam/foam). Finally, microplastics were then analyzed
using an FT-IR microscope for polymer type characterization. The results obtained demonstrate that
the beaches of the city of Rio de Janeiro had an average abundance of 113 ± 81 particles/kg, thus
being consistent with other beaches in the world. Botafogo beach had the highest abundance of
microplastics with mean values of 343 ± 236 particles/kg, a result of the legacy of contamination
from Guanabara Bay. The plastic particles examined ranged from 0.6 to 2.4 mm, with more than 50%
having a size of less than 1 mm. Fragments, films, lines/fibers and styrofoam/foams were found, with
lines and fragments being the most abundant, representing 61% and 27%, respectively. The most
abundant colors were blue (35.6%), black (25.8%) and transparent (18.7%). The polymers analyzed
by micro-FTIR showed a spectrum with bands of functional groups characteristic of polyurethane,
phenol formaldehyde resin or phenolic resin (PF), polyvinyl acetate polymer (PVA),
polyvinylcarbozol-PVK. Based on the results obtained, it is concluded that the beaches of the city of
Rio de Janeiro show contamination by microplastics (abundance, type and color) consistent with other
beaches in large cities in the world, with the exception of Botafogo beach, which had the highest
abundance among the beaches. It is understood that the routine garbage collection carried out on the
beaches by the city's urban cleaning company contributes to reducing the formation of secondary
microplastics on the main beaches of the city. Further studies must be carried out to better understand
the possible sources of microplastics and their possible consequences for the coastal environment
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