A Systematic Review of Microplastic Contamination in Tuna Species: General Pathways into the Food Chain with Ecotoxicological and Human Health Perspectives.

Tuna species, as highly migratory apex predators of major commercial significance, play a vital role as biological indicators of microplastics (MPs) contamination due to their trophic position and wide geographic distribution. Current systematic review aims to analyze the occurrence, characteristics, and concentrations of MPs in various tuna species. Data from 19 studies were compiled, focusing on the presence of MPs in different organs (gills, muscles, gastrointestinal tracts). High concentrations of MPs were found in tuna species from the Bay of Bengal (42.13 ± 13.58 MPs/individual in Thunnus obesus) and the Persian Gulf (5.71 MPs/individual in Thunnus tonggol), indicating significant contamination in these regions. Polyethylene (PE) and Polypropylene (PP) were the most commonly detected polymers, suggesting their widespread presence in marine environments. The dominant size range of MPs was 0.5-2.5 mm, with fibers and fragments being the most common shapes. The presence of MPs in edible tissues raises concerns about potential health risks for both marine life and human consumers. Future research should focus on expanding geographical coverage and investigating the ecological and health impacts of MPs ingestion. Long-term monitoring and international collaboration are essential to address this global environmental challenge effectively.