Marine organisms, especially mussels, can efficiently take up microplastics (MPs) through their filtration processes. This study evaluated the characteristics of MPs in green mussels (Perna viridis) sold at traditional seafood markets in Jakarta, Indonesia. The polymers of MPs were examined using Fourier Transform Infrared spectroscopy, while the chemical components of MPs in green mussels were analyzed using Gas Chromatography-Mass Spectrometry. The MPs identified in green mussels sold at traditional seafood markets in Jakarta are predominantly of fiber type, display a black coloration, and measure <
100 μm in size. The density of these microplastics in green mussels is uniform across all traditional markets. The concentration of microplastics in green mussels correlates positively with the length of the green mussel shell. The average annual consumption of mussel products by people in Jakarta was 11,170 items/year/person. Green mussels from Jakarta exhibited a significantly elevated polymer hazard index (III), indicating the presence of polymers categorized as high risk. Certain plasticizers (phthalates) and specific additive chemicals (phenol, butylated hydroxytoluene, and hexadecanamide) were also present in green mussels sourced from traditional markets in Jakarta. These substances are toxic and have a negative impact on both aquatic life and humans.