Estudo de Microplásticos em Diferentes Matrizes Ambientais da Bacia do Alto Tietê

Resumo (EN)

In recent years, microplastics (MPs) have become a growing concern for both the scientific community and the general public, as these plastic particles disperse widely across various ecosystems. Acting as transport vectors, MPs can travel far from their sources of pollution and are found in urban, rural, and forested areas. Once present in these ecosystems, it is known that both vertebrates and invertebrates, such as fish and macroinvertebrates, can ingest MPs, which may then be transferred along the food chain. Moreover, MPs contaminate other components of these environments, such as sediments, which can also serve as a source of contamination for organisms that feed, shelter, or reproduce there. Located in the metropolitan region of São Paulo, the Upper Tietê River Basin is characterized by gentle relief and low altitudes. Covering an area of 5,775 km², it includes small springs, tributaries, and streams that flow into the Tietê River. The region is subject to various anthropogenic activities, such as deforestation, urbanization, and improper disposal of industrial effluents, which pose serious risks to aquatic ecosystems. Existing conservation units have partially fulfilled their role in preserving these areas; however, due to its location in Brazil’s most densely populated region, where urban expansion is intense and MPs are widely dispersed, even remaining natural areas face contamination risks. As part of the PAN Alto Paraná (National Action Plan for Endangered Species of the Upper Paraná), sampling campaigns were conducted in municipalities within the Upper Tietê River Basin. Considering the ecological relevance of the region and the essential role played by the species found there, this study aimed to identify, quantify, and characterize the presence of microplastics in urban, rural, and forested areas through the collection of water, sediment, and fish samples from streams in the Upper Tietê sub-basin. Sampling sites were selected based on land use and land cover, allowing comparisons among different environmental contexts. The analyses revealed significant differences in microplastic quantities across environmental matrices, particularly between water and fish. Additionally, data on ecomorphology, diet, and microplastic contamination were integrated for the fish species analyzed. Among the findings, species of the order Siluriformes generally showed the highest levels of microplastic ingestion, which may be related to their benthic behavior and greater interaction with the substrate, where these contaminants tend to accumulate. Alarmingly, this pattern was predominantly associated with a species considered to be threatened with extinction.