Variabilidade espacial e temporal de microplásticos em córregos urbanos do município de Cuiabá-MT

Abstract

The ingestion of microplastics (MPs) adsorbed with toxic substances, such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), organochlorinated pesticides (OCPs), antibiotic and potentially toxic metals, can generate physiological pacts in aquatic organisms, and which consequently can cause direct and indirect harmful effects in humans. However, the presence of these residues in urban lytic environments, dependent on a number of variables related to these residences, such as the release of domestic effluents and the collection of waste in general. The main objective of this study was to investigate the spatial and temporal variability of MPs in urban streams obtained from sediments, collected in eight tributaries of the Cuiabá-MT river basin. It was verified through environmental perception, the surroundings of the exutories in their main tributaries of the Cuiabá river basin and, it is recorded all types of waste found, in addition to the collections performed. The temporal and spatial influence on the type and quantity of MPs present in the sediment of the collection sites was investigated and confirmed. The methodology applied in this study was the use of secondary data of morphometric characteristics of urban streams. For the processing of samples of plastic bags classified in various colors and characteristics, the isolation of this material was used with adaptations of laboratory methods for analysis, together with methodologies used in scientific studies carried out on Isolated MPs in freshwater environments. Subsequently, sediment and plastic packaging samples were submitted and analyzed in triplicate. Several fibers of these residues were obtained in variable colors and sizes in the months of collection during the rainy season from November/2019 to January/2020 (Graphs 1, 2 and 3, respectively). Thus, it was observed that in the months of study had the following accumulated occurrences of precipitation: November/19 (57.30mm), December/19 (212.60mm), and January/20 (182.60mm). In the dry season, the month of August/20 was recorded with zero (0.0mm), followed by September/20 (1.90mm) and October/20 (93.60mm). Configuring the month of December/19, give it greater rainfall intensity, and consequently greater probability of an increase in the number of sediments and waste carried for water bodies. For the fibers of MPs obtained satisfactory results, proving the presence of these residues in various types of size and colors in this habitat, bringing serious concerns of pollution and degradation in the environment and aquatic life. It was concluded that it was not possible to find the potentially toxic metals in these watercourses adsorbed in The MPs and sediments, however, it is necessary to have more scientific studies to confirm these results. Several mps fibers were found in different colors and dimensions, derived from the decomposition of the discarded materials in the water courses and by the release of washing water.