Microplastics in a Brazilian Southeast Bay

RESUMEN

Introduction: Microplastics represent an unprecedented environmental impact. Seas and bays worldwide contain microplastics. Sepetiba Bay is an industrial and artisanal location with a port. It can be considered a rural area in which artisanal fisheries contribute to local development. However, rivers flow into the bay, carrying plastic pollution in addition to local irregular disposal. 

Materials and Methods: To evaluate and quantify microplastics, coastal sediments and seawater were collected in 2023. Floating solutions (25% KCl, 25% NaCl, or 25% Na2CO3) were used to separate less-dense microplastics, which were then evaluated by optical microscopy. ImageJ was used to quantify microplastic diameter. 

Results: Dozens of microplastics were encountered, with morphologies including fibers, particles, and films; most exhibited weathering. They were grouped into fragments, fibers/filaments (high aspect ratio), and microspheres for quantification. In Sepetiba Bay, there were 1.13 microplastic particles/ml of seawater and 2.32 microplastics/g of sediments, most probably of commodity polymers. Regarding the microplastics encountered, ~6% were microspheres, 38% were fibers, and 56% were fragments. It indicates that water discharged from washing machines and the textile industry, as well as fragments from improper disposal of single-use packaging, may be sources of microplastics.

Conclusion: Microplastic pollution in this bay is primarily composed of fragments and fibers, indicating uncontrolled disposal of plastic materials.

Palabras clave: microplastics, pollution, bay.