Análise da deriva de microplásticos na Lagoa de Araruama - RJ

Abstract

This study presents an analysis of microplastic transport in Araruama Lagoon, RJ. Microplastics were categorized by density relative to local water: light, which float; neu- tral, which are distributed throughout the water column; and dense, which tend to sink, possibly depositing and later resuspending. This work was supported by a 3D hydrodynamic model developed with SisBaHiA – Sistema Base de Hidrodinâmica Ambiental. Based on the hydrodynamic model, lagran- gian transport models were constructed to analyze microplastic transport in the lagoon. Separate models simulated surface transport for light microplastics, mid-water column transport for neutral microplastics, and bottom-layer transport for dense microplastics. Hydrodynamic results showed that in the inner lagoon, the primary driving force of flow is the wind, predominantly from the northeast, while tidal forces are more influential near the Itajuru Channel. Findings indicate that light microplastics tend to be transported and accumulate along the lagoon's southern margin; neutral microplastics become trapped in vortices forming in various coves; and dense microplastics tend to accumulate along the northern margin, near their sources. It was found that the lagoon accumulates microplas- tics rather than exporting them to the sea.