Tracing the Journey of Microplastics from Aquatic Ecosystems to Seafood

Microplastic pollution has become an important environmental issue due to the widespread occurrence, persistence, and biological accessibility of small plastic particles in aquatic ecosystems. Fish and other seafood organisms are of particular concern because they may come into contact with microplastics at different stages of their life cycle. These particles can be taken up directly from contaminated water and sediments or indirectly through the consumption of contaminated food. Microplastics have been reported in numerous marine and freshwater organisms, including commercially valuable fish, crustaceans, and bivalves. Their detection in gastrointestinal tracts and, in some cases, edible tissues has raised concerns about seafood safety and quality, ecosystem health, and the possibility of human exposure through seafood consumption. The effects of microplastic ingestion on aquatic organisms are not uniform and can vary according to several characteristics of the particles, including their size, shape, polymer type, concentration, and the chemicals or microorganisms associated with their surfaces. Ingested microplastics may interfere with normal digestive processes and can potentially contribute to oxidative stress, inflammation, changes in feeding behaviour, and other physiological disturbances. Moreover, plastic particles can act as carriers or surfaces for environmental contaminants such as persistent organic pollutants, heavy metals, and microorganisms. These interactions may influence the availability, transport, and exposure of aquatic organisms to such contaminants. The movement of microplastics through aquatic food webs is also complex. Unlike certain persistent chemical pollutants, microplastics do not necessarily undergo progressive biomagnification at each successive trophic level. However, feeding relationships can provide opportunities for microplastics and their associated contaminants to move between organisms and reach higher-level consumers. As seafood forms an important component of the human diet, consumption of contaminated fish and other seafood represents one possible route of human exposure to microplastics. However, the actual level of dietary exposure and the extent to which such exposure poses a health risk to humans are still being investigated.