Investigação da ingestão de resíduos plásticos por arraias potamotrygoninae em praias da Amazônia Brasileira

Abstract

Plastic waste pollution is among the main environmental challenges today, with a growing impact on aquatic ecosystems, especially on the riverine environments of the Amazon. This thesis aimed to investigate the ingestion of plastic waste by freshwater stingrays of the subfamily Potamotrygoninae on beaches around Manaus, Amazonas, integrating ecological, environmental, and socio-behavioral approaches. To this end, the socioeconomic profile and environmental perceptions of beach users regarding the improper disposal of waste were evaluated, as well as the occurrence, distribution, and characterization of plastic particles in environmental matrices (water and sediment) and in biota (6 species of stingrays). The results showed the wide distribution of plastic waste in the studied areas, with a predominance of particles in the water column (1404), followed by sediment (456). Ingestion of plastic debris was recorded in Paratrygon aiereba, Potamotrygon constellata, Potamotrygon marquesi, Potamotrygon motoro, Potamotrygon orbignyi, Potamotrygon schroederi, and Potamotrygon wallacei, and was more associated with bioturbation behavior and the bioavailability of particles, with greater vulnerability in the younger portion of the population. Polypropylene, polyethylene, and polyethylene terephthalate were identified as possible polymers. It was observed that the beaches act as accumulation zones for these contaminants, influenced by the proximity of the city of Manaus, anthropogenic pressure, and the hydrological dynamics of the Rio Negro. There is a divergence between beachgoers' environmental perceptions and their actual litter-disposal practices on beaches, indicating limitations in the effectiveness of environmental education efforts. The results demonstrate a continuous flow of contaminants between the environment and the biota, indicating chronic exposure for the rays. It is concluded that neotropical rays present themselves as potential bioindicators of environmental quality and that tackling plastic pollution in the Amazon requires integrated strategies that combine environmental monitoring, solid waste management, and environmental education.