Chemical characterization of plastic pellets collected fron various beaches nationwide

Abstract

This research presents a detailed chemical characterization of plastic pellets collected from several Spanish beaches to assess their composition and environmental degradation status. Samples were analyzed using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), a technique that allows the identification of polymer types and degradation indicators such as oxidation-related functional groups. Most samples were identified as polyethylene (PE), with a few cases of polypropylene (PP) and latex (LX), while others remained unidentified due to advanced degradation or spectral ambiguity. The analysis revealed varying degrees of weathering and oxidation, with more intense degradation observed in samples from Barcelona and Playa Grande (Tenerife), and better-preserved pellets found in Garachico and Menorca. Furthermore, a separate methodological section explored the correlation between the yellowness index (YI) and RGB color values using a reference dataset, with the aim of developing a color scale as a tool to visually estimate degradation levels. The results contribute to a better understanding of plastic pollution along Spanish coasts and highlight the importance of both spectral and visual indicators in assessing the environmental impact of microplastics.