Quantitative assessment of microplastics in fish from the Gulf of Guinea, Ghana, using LDIR spectroscopy: Implications for marine food safety and health risk evaluation.

In this study, microplastic (MP) contamination was investigated in 24 marine fish species from 3 environmental hotspots- Labadi, Teshie, and Jamestown, along Ghana's Gulf of Guinea coastline. Specific fish species studied included Pseudotolithus senegalensis, Sphyraena guachancho, Brachydeuterus auratus, Chloroscombrus chrysurus, and Ethmalosa frimbriata. Fifty-eight percent of the total MPs were detected in the gastrointestinal tracts, and 42% detected in gills of 177 individual fish tested in this study. Labadi showed the highest contamination levels [mean MP concentration: 22 ± 19 (items fish)-1]. Omnivorous fish species had the highest mean ingestion rate of MPs (19.4), surpassing both carnivorous (17.7) and herbivorous species (13.5), and indicating dietary habits as a significant factor in MP bioaccumulation. White-coloured MP films (60%) of sizes: 100-1000 µm were the dominant ingested shape. Other MP shapes included fragments (26.3%), fibres (10.5%), beads (1.05%), and foam (0.61%). Using advanced spectroscopic technique such as Laser Direct Infrared (LDIR) Imaging, 16 MP polymers were characterized with polyvinyl chloride (PVC) being the prevalent MP polymer type (80%). The study observed a strong positive correlation between carnivorous demersal and omnivorous pelagic-neritic fish for specific MP polymers, suggesting that factors other than polymer density influence MP consumption patterns for fish habitats within the water column. The annual MP exposure to Ghanaian adults via fish consumption [(194-29,239 MP items (person year)-1] significantly exceeded the European Safety guidelines [518-3078 (items year)-1], emphasizing dietary habits and environmental pollution as key factors. This study provides a critical baseline on MP pollution in Ghanaian marine ecosystems, highlighting the urgent need for interventions to mitigate plastic pollution, protect marine biodiversity, safeguard marine food, and public health in West Africa.