Presença de microplásticos em sedimento intertidal e tecidos de bivalves economicamente importantes: avaliação pós-engordamento de trechos de praias urbanas

Abstract

Microplastics are defined as particles smaller than 5 mm in size, which can be derived from the degradation and breakdown of larger plastics or can be produced in microscopic size and placed in aquatic environments. Such particles can be assimilated by many marine species, leading to physical damage and toxic effects, in addition to accumulating in marine organisms by various routes, reaching edible species and causing risks to human health. The various impacts caused by MPs on the biota have already been studied, however, in Brazil, the studies are in an initial phase. In addition, the study areas, located on Camburi and Curva da Jurema Beaches, in Vitória, ES, have recently gone through a process of fattening of the sand strip, considerably modifying the composition of the beach sand, which could alter the amount of MPs in the region. Thus, the present study aimed to compare the abundance and distribution of MPs found in intertidal sediments and in specimens of the bivalve molluscs Crassostrea brasiliana, Mytella strigata, Perna perna and Tivela mactroides, collected on the beaches of Camburi and Curva da Jurema, Vitória, Southeast of Brazil, in a post-fattening situation. For that, three samples of interdital sediment were collected in five sampling points, in addition to 20 individuals of each species in two sampling points. The MPs found in the study were collected and deposited on filter papers arranged in Petri dishes, where they were viewed under a magnifying glass, photographed, quantified, classified by type, color and stored for statistical analysis. The results found show that there was an increase of 171.41% in the total amount of MP after fattening process. Filaments were the dominant MP types in the two years of study. In 2020 blue filaments were more abundant among MPs, while in 2021 the highest number of MPs found represented black. The expressive increase in the number of MPs after the fattening process indicates that this type of action can lead to a drastic increase in microplastics available in the environment, further increasing the risk of contamination of the local biota, thus reaching humans via the food chain