Spatio-temporal evaluation of macro, meso and microplastics in surface waters, bottom and beach sediments of two embayments in Niterói, RJ, Brazil.

This study evaluated in the dry and rainy periods, the anthropogenic influence and the hydrodynamics in the distribution of plastic items in surface waters and bottom and beach sediments of the Jurujuba (Guanabara Bay, low and medium hydrodynamic) and Itaipu (oceanic region, high hydrodynamics) embayments; places of cultivation and extraction of mussels. Microplastics were 83% of the wastes collected, with a higher average concentration (138.41 items.kg-1) in beach sediments. High density polyethylene (HDPE) (38%), polypropylene (21%), and styrene (10%) were the most frequent polymers. There was no difference between the water and bottom sediment samples in the different embayments, in the studied periods, different from that observed in the beach sediment samples, with higher concentrations in the rainy season in Jurujuba. The results suggest that beach sediments are the best compartment to understand the dynamics of the distribution of plastic waste over time.

Marine debris on beaches of Arraial do Cabo, RJ, Brazil: An important coastal tourist destination.

Arraial do Cabo, RJ, Brazil, is known as the diving capital due to its clear waters and great biodiversity, a consequence of the upwelling phenomenon. This feature attracts tourists tripling their population during holidays, causing increase in the amount of debris on beaches and waters endangering marine biodiversity. To evaluate the amount of solid waste found on beaches in two different holiday period, eight people in each beach collected macrodebris (≥2 cm) in a transect covering an 20 m wide area, during 20 min, in winter/2015 and summer/2017. The materials were weighed, quantified and characterized. In the summer, when the number of tourists is greater, a larger total amount of waste in units were found. Plastic and cigarette butts were the most abundant. The results show that the city does not have adequate planning to receive a large amount of tourists, being vulnerable to socioeconomic and environmental damages.