Morphology, Chemical Characterization and Sources of Microplastics in a Coastal City in The Equatorial Zone With Diverse Anthropogenic Activities (Fortaleza City, Brazil)

<title>Abstract</title> The aim of the present study was to perform morphological and chemical characterizations of microplastics (MPs) found in seawater samples from the coast of the city of Fortaleza (CE) using Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy and differential scanning calorimetry (DSC). Sampling was performed using a neuston sampler. MPs were separated based on the difference in density. MPs with varied morphologies were found. Fibers and fragments were the most abundant (57% and 36.2%, respectively). FTIR, Raman spectroscopy and DSC confirmed the presence of polyurethane and alkyd resin, polyethylene, polypropylene, polystyrene, polyamide blends, thermoplastic rubber and polyester fibers. Many studies have chemically characterized plastic materials using FTIR, Raman spectroscopy and DSC and common MPs, such as polyethylene, polypropylene, polyamide and polyester, have been characterized. However, characterization becomes more complex when MPs are less common particles, weathered particles and blends of polymers and additives. There is also less information on these types of MPs in commercial polymer databases. Therefore, the MP spectra obtained in this study can serve as a database to compare and characterize common as well as less common, more complex MPs.