Microplastic Accumulation in Commercially Important Black Sea Fish and Shellfish: European Sprat ( Sprattus sprattus ), Mussels ( Mytilus galloprovincialis ) and Rapa Whelks ( Rapana venosa )

Microplastics (<5 mm) have become a pervasive pollutant because of their persistence, bioavailability, and risk of trophic transfer. The present work provides new evidence on microplastic contamination in three economically important species from the Romanian Black Sea coast: Mytilus galloprovincialis , Rapana venosa , and Sprattus sprattus . Microplastics were extracted using 10% potassium hydroxide (KOH) chemical digestion and examined under a stereomicroscope. Microplastics frequency of occurrence (FO%) ranged from 66.7% to 93.3%, with mean abundances per individual being 3.06 ± 3.71 in mussels, 3.26 ± 2.08 in rapa whelks, and 3.13 ± 2.44 in sprats. Fibers were the dominant type, followed by fragments, with blue, black, and transparent colours most common. Most particles were within the 1–5 mm and 330 µm −1 mm size classes, with smaller fractions between 100 and 330 µm, indicating ingestion of particles large enough to accumulate rather than be rapidly egested. The microplastic contamination found in predatory R. venosa suggests trophic transfer of microplastics from bivalve prey. As all three species are consumed by humans, they represent potential pathways for microplastic exposure. These results emphasize the urgent necessity for additional research on sources, environmental pathways, and possible health risks of microplastics in the Black Sea.