A review on microplastics in bivalves: analysis, quantification, and effects

Microplastics (MPs) contamination poses serious risks to aquatic ecosystems and food security, as bivalves and other marine organisms easily ingest these particles. Bivalves are of particular concern due to their ecological roles, wide distribution, and importance in the human diet. To better understand the bioaccumulation of MPs and contamination in the food chain, we reviewed 56 published articles (2016-2024), including experimental studies, biomonitoring, and prevalence of MPs, using keywords related to microplastics, bivalves, abundance, shape, and color. Overall, the reviewed studies indicate that bivalves accumulate a variety of microplastic forms, with fibers consistently dominating fragments and other morphologies. Polystyrene and polypropylene were the most commonly reported polymers, while black and white particles represented the most common colors. Reported loads of MPs varied considerably across species and geographic regions, reflecting differences in local sources such as fishing gear, textiles, and human activities. These findings underscore the role of bivalves as reliable bioindicators of MPs pollution, and emphasize their importance not only in monitoring ecosystem health but also in informing management strategies and safeguarding food security.