Quantificação e distribuição vertical de microplásticos na coluna d’agua em represa urbana

Abstract

In recent years, research has shown the presence of microplastics in aquatic environments worldwide. Microplastics are 5 mm or less, reaching up to a few micrometers. The main focus of research on microplastics is the marine environment, doing microplastics in the freshwater environment a vast field for further studies. In this study, 36 water samples were collected in an urban area over a period of six months (July to December), with half of the samples being collected on the water surface and the other half in the middle of the water column. In the laboratory the samples were purified and analyzed by the visual method with a microscope. The results were quantified and cataloged in terms of size, shape and color. This study identified 184 microplastic particles in the samples, indicating a predominance of transparent microplastics over colored and filaments over fragments at the study site. An average total of 20.99 particles/m³ was recorded. There was a small monthly variation in microplastic abundance regardless of depth, except in November and December, which had a significant variation. This study indicates that for a correct observation of microplastic abundance it is necessary to analyze the abundance in multilayers of the water column. The results point to a greater abundance on the surface than in the middle of the water column. Further studies are needed with a longer monitoring period to analyze, for example, ensure the influence of rainfall.