Fatores relacionados à deposição de resíduos sólidos em uma praia flúvio-estuarina amazônica

Abstract

Brazil has a coastline that stretches for 8,698 kilometers, housing over 400 municipalities and a high population density, as it serves as a source of multiple income-generating activities. However, the lack of infrastructure and improper waste disposal lead to the dumping and accumulation of trash at the coastal zone. As a result of high consumption, a significant amount of waste is generated, most of which is discarded incorrectly and leads to social, environmental, and economic damage. Despite its environmental and social significance, studies are scarce on estimates of the quantity of waste and its distribution in coastal environments of the Amazon. The objective of this study was to identify the occurrence, abundance, distribution, and types of waste found on a fluvial-estuarine beach (Beja Beach, Abaetetuba-PA) and possible spatial and temporal deposition patterns. The beach was divided into two areas: northeast and southwest, with sampling at two levels (intertidal at the low tide line and lower intertidal); collections took place during the rainy season (March to May 2022) and the less rainy season (October and November 2022). In each seasonal period, six samplings were conducted, with three during spring tides and three during neap tides. During the rainy season, a total of 902 items were collected, with a total mass of 70.38 kg (an average of 1.87 items/m² and 0.141 kg/m²), and during the less rainy season, a total of 536 items were collected, with a mass of 12.99 kg (an average of 1.07 items/m² and 0.026 kg/m²). It was observed that the most collected items during the 12 campaigns were single-use plastics. There was a higher quantity of items, both in the rainy and less rainy seasons, in the upper intertidal zone, in the SW sector, and during spring tides (p < 0.01). Regarding mass, significant differences were observed for seasonality and zonation. Significant differences were found in the relationship between factors such as intertidal zones for both seasonal periods and tidal levels. Studies conducted in other regions of Brazilian territory also observed that the most found solid waste was plastic, especially single-use plastics. One of the factors that can explain this occurrence is the fact that the market increasingly invests in packaging and single-use plastics and the use of such products by beachgoers in the referred beach. Improper disposal leads to the incorrect disposal of these materials in the environment. The results described here provide managers with information to develop more effective strategies for the management, handling, and cleaning of beaches in the region.