Microplastic pollution and risk assessment in urban beaches of the Caribbean region

BACKGROUND AND OBJECTIVES: Microplastic pollution on tropical urban beaches is a growing concern due to its persistence, mobility, and potential transfer to coastal organisms. While research on marine ecosystems has advanced significantly, substantial gaps persist regarding their spatial distribution, community composition, and the ecological risks facing urban beaches in the Colombian Caribbean. The study objectives were to assess microplastic pollution and associated risks on three urban beaches in San Antero, Córdoba, considering its spatial and seasonal variability and potential anthropogenic sources.METHODS: Surface sediments were collected from Blanca, Bucaneros and Puerto beaches, including the supralittoral, mesolittoral, and infralittoral zones during rainy, transitional, and dry periods. Microplastics were separated via density separation using a saturated sodium chloride solution, subsequently filtered, and evaluated for morphological characteristics, dimensions, and coloration through stereomicroscopic. The polymer composition was determined using Fourier transform infrared spectroscopy. In addition, pollution indices, morphological impact, potential ecological risk, pollution risk, and source contribution were applied.FINDINGS: Abundances ranged from ۵۳۰ to ۱۳۹۲ particles per kilogram, with the highest values ​​during the rainy season, in the supralittoral zone, and at Puerto beach. Fibers overwhelmingly dominated the morphological composition, representing ۹۶ percent of the particles and irregular fragments constituted ۴ percent. Blue and white particles predominated within the samples, whereas infrared spectroscopic analysis of a representative subset identified polyethylene terephthalate and polypropylene as the primary polymer types. Although the indices based on abundance and polymer composition indicated low pollution and low ecological risk, the predominance of fibres and the high values ​​of the source contribution index evidenced continuous anthropogenic inputs.CONCLUSION: The urban beaches evaluated function as microplastic accumulation zones potentially influenced by rainfall, coastal dynamics, tourism, fishing, and urban activities. These findings emphasize the imperative to enhance plastic waste management strategies and environmental surveillance across tropical coastal zones within the Colombian Caribbean. These findings provide baseline information for tropical urban beaches and support the development of source-oriented strategies to reduce microplastic inputs into coastal ecosystems.

کلیدواژه ها:

Anthropogenic sources ، Caribbean beaches ، Microplastic ، Pollution indices ، Polymer characterization