Macroplastics in the Guarapiranga reservoir (São Paulo, Brazil): estimating the generation of microplastics

Pollution control of continental waters is essential, especially reservoirs, as they are the source of public supply. One of the main protagonists of this pollution is plastics and their size influences the levels of negative impact on the environment, and this study identified macroplastics ¿ 5mm and microplastics 1mm ≤ 5mm. The Guarapiranga Reservoir is the second largest supply system in the São Paulo Metropolitan Region, so it is necessary to guarantee its noble use to maintain supply and public health. The study aims to estimate the amount of microplastics that the macroplastics collected on the banks of the reservoir can generate in two seasonal seasons, dry and rainy, identifying the main polymers, product function, mass and volume. The dry season field collection took place in June 2023 and the items were sorted by washing, photographic recording, counting, weighing, identification by evidence or ATR FT-IR spectroscopy technique. 315 items were collected at 9 points, resulting in 7 items/m² and 1,268 g. The most commonly found polymer was PP, mostly found in disposables and packaging, followed by EPS, for food packaging and HDPE, found in bottle caps. These polymers corroborate the most prevalent land use and occupation: leisure areas, i.e. the waste from consuming drinks and food during leisure time at the reservoir is not properly disposed of post-consumption. The maximum projection of microplastics (1mm particles) was 2.27x1014 items/m² and the minimum projection (5mm particles) was 1,814 items/m² in a total volume of 1,135 cm³. The potential for long-term pollution is evident, making it a tool for developing public policies on plastics, reinforcing existing ones and investing in water treatment technologies. Also see: https://micro2024.sciencesconf.org/559494/document