Distribuição espacial e caracterização de microplásticos em ambientes aquáticos do arquipélago das Ilhas Canárias

Abstract

Microplastic pollution has become a global environmental issue, particularly relevant in marine and insular systems. This dissertation aimed to investigate the spatiotemporal distribution and characterization of microplastics in aquatic environments of the Canary Islands archipelago, considering abundance, particle size, morphology, and polymer composition. Sampling was conducted during three oceanographic campaigns, in which surface microplastics were collected and analyzed using spectroscopic techniques. A total of 780 particles were recorded, with a predominance of fragments (57.9%) and fibers (40.0%). Polyethylene terephthalate (PET) and low-density polyethylene (LDPE) were the most frequent polymers. Particle size showed high variability, indicating structural heterogeneity of contamination. Microplastic abundance differed significantly among campaigns, with the RAPROCAN25 campaign accounting for more than 80% of the total records, as well as exhibiting the highest densities and the most intense local accumulation areas (hotspots). Significant differences in morphotype and polymer composition among campaigns suggest variations in input sources, transport pathways, and environmental processing, with a strong association between fibers and PET and between fragments and polyolefins. Overall, the results indicate that microplastic contamination in the Canary Islands is spatially aggregated, compositionally dynamic, and predominantly derived from secondary sources. The distribution patterns are strongly influenced by the interaction between the Canary Current, the connectivity with the North Atlantic subtropical gyre, anthropogenic pressure, and local geomorphological features, which favor retention and accumulation processes. In this context, the archipelago acts as a strategic zone for the interception and redistribution of marine pollutants at the oceanic scale, highlighting its importance as a key area for monitoring and understanding microplastic polluti