Caracterização da poluição por microplásticos no litoral de Limón, Caribe Sul da Costa Rica, como subsídio à gestão costeira

Abstract

Pollution by solid waste tends to cause severe social and environmental damage and compromises coastal and marine ecosystems. This study aimed to characterize the temporal and spatial occurrence of microplastics present on the beaches of the coast of Limón, southern Caribbean of Costa Rica, and identify their possible sources. The selected beaches comprise a stretch of 70 kilometers long, characterized by having large areas for environmental protection, agricultural and residential areas with low occupation density, urban and port areas. The rapid urban and industrial growth that has been occurring in the last decades, with the construction of a port, the container terminal of Moín and an international airport, allied to the strong tourism of the region, is worrying, mainly because of the very dynamic. The coast of Limón has a high susceptibility to the occurrence of earthquakes, mass movements, hurricanes and problems with coastal erosion and floods. Despite the great importance for the country, this Caribbean coast is poorly studied and studies related to coastal dynamics and pollution by solid waste are still scarce. The research methodology consisted of a comprehensive bibliographic review on the subject in question and the performance of several laboratory analyzes on the materials collected on the beaches in 2017 and 2019, for the sedimentary characterization and the content of micro solid residues. The results show that the beaches studied in the northwest sector had the highest concentrations of microplastics, with emphasis on Cieneguita and Aeroporto, with a predominance of pellets, followed by fragments. These beaches are dynamic, consisting basically of fine sands; they are inserted in a coastal stretch with a strong concentration of industrial, port and airport activities, also marked by violence and environmental problems. The lower occurrence of microplastics in the southeast sector may be related to the greater number of preservation areas and the smaller number of possible sources. On the beaches of Manzanillo and Gandoca, fine to medium sands are poorly selected, with a high concentration of heavy minerals. With varying sizes, shapes and colors, most microplastics had a worn appearance, which suggests the reworked by the coastal processes and their subsequent deposition on the studied beaches. The impact of this type of pollution on the coast of Limón is notorious and deepening the knowledge of this problem will support the implementation of measures and laws that aim to reduce the damage caused by microplastics to Costa Rica's biodiversity and geodiversity.