Combination of Micro‐Raman and Infrared Spectroscopy to Identify Intriguing Case of Aged Microplastics of Estuarine Sediments

Abstract The Atlantic Forest is one of the richest regions in biodiversity in the world. Originally the biome covered around 15% of the Brazilian territory. Currently, there are approximately 12.4% of forest remnants preserved in the country. Regarding mangrove areas in the state of São Paulo, there are around 223 km 2 according to the Brazilian Mangrove Atlas, with around 120.5 km 2 located in Baixada Santista. Analysis of sediments found in the estuarine mangroves of Santos shows a high concentration of microplastics (MPs), generated by industrial processes and human activity, that constitutes today one of the main environmental problems. The MPs presented in the sediment samples are quantified using a methodology that involves drying, sieving, quantification, and identification of these MPs through FTIR and micro‐Raman spectroscopy. The two techniques complement each other to identify MP filaments and fragments through common polymer spectra. Furthermore, the micro‐Raman technique also identified additives flexo blue (blue ink) and neolan green 8G (dye) in MPs. All identified polymers (< 5 mm) have wide applications and demands in various sectors, including packaging, construction, automotive, electronics, and textiles.