Analysis of the Microplastic Pollution Index (MPI) in the sandy sediment of the coast of the capital of Sergipe

Abstract

Brazil is the fourth largest plastic waste polluter in the world. When degraded by weathering, these plastics break into smaller particles than 5 mm, known as microplastics (MPs), and accumulate on beaches. These MPs cause negative impacts on both the environment and marine life. The aim of this research was to analyze the MPs found in the sand strip (SS) and in the vegetation strip (VS) of the beaches of Aracaju, Sergipe. Sand samples were collected superficially from October 2023 to April 2024 in 10 quadrants of 50 cm x 50 cm, in each strip, within a 2,000 m² area. The MPs were extracted from the sand, counted, and classified according to shape and color. Subsequently, the Microplastic Pollution Index (MPI) was calculated. Among the 438 MPs counted, the “Fragment” shape and “White” color were the most prevalent, with 87% and 69% respectively, with higher frequency in the VS (p < 0.001). Viral Beach showed the highest concentration of MPs compared to all others (p < 0.001). The highest MPI recorded was at Viral Beach, with 14 MPs/m². The average for the beaches was 7.3 MPs/m², which classifies them as “Moderate Abundance.” The results are useful for supporting solid waste management in coastal areas and demonstrate the need for public and social actions focused on environmental education and ecosystem conservation, especially regarding the conscious use and correct disposal of plastics.