Análises de microplásticos em praias da ilha de Mosqueiro, Pará, Amazônia, Brasil.

Abstract

Microplastics are fragments of plastic whose size does not exceed 5 mm. Plastic pollution in the oceans, mainly plastic items smaller than 5 mm, called microplastics (MPs), is a ubiquitous environmental problem. Virgin plastic spherules (pellets) and plastic particles used by industries are defined as primary microplastics and reach the marine environment through loss during their production chain and through the discharge of wastewater. Secondary MPs result from the fragmentation of larger plastics, due to the physicochemical degradation process. Beaches are sedimentary environments where materials accumulate and, as such, are hot spots for plastic contamination. This study seeks to quantitatively evaluate MPs, classify which types of plastic predominate and characterize their chemical composition, on sandy beaches located on the island of Mosqueiro, PA –Brazil, considering that there are still no studiesfocused on this topic in this region. The sediment samples were obtained during the year 2022, in the months of October and December on the beaches of Chapéu Virado and Marahu located on Ilha de Mosqueiro. The collection was carried out along the high tide line, on each beach 10 quadrants were sampled, thus composing 10 independent samples on each beach, where each was 20 m away from the other, collected superficially, at a depth of 1 cm. After collection, the samples were transported to the Chemical Analysis Laboratory where they were dried in an oven at 60° C, followed by flotation using a ZnCl2 solution to separate the MP's from the sand through the difference in densities, then it was vacuum filtration was carried out using fiberglass filters where the MP's were retained and finally classification under a magnifying glass with 40x magnification. Microplastics were found in all 40 sampled points, where 1245 Microplastics (MPs) classified as secondary were identified, 1241 units (units) of filaments and 4 units. of fragments. Marahú beach had a higher quantity of PM particles compared to Chapéu Virado beach. Local hydrodynamics can influence the deposition of microplastics and can also be responsible for their transport to adjacent regions.