Occurrence, trophic transfer and risk assessment of microplastics in fishery organisms from the Bohai Sea, China

Marine microplastic (MP) pollution has emerged as a critical environmental issue, posing significant risks to a wide range of marine organisms. However, the trophic transfer of MPs with different characteristics among marine species remain poorly understood. This study investigated the abundances and characteristics of MPs in various fishery organisms from the Bohai Sea, China, and evaluated the influencing factors, trophic transfer and associated risks. Results showed that MP abundances ranged from 0.50 ± 0.52-2.38 ± 1.41 items per individual. Most MPs were smaller than 1 mm (74.6 %), with fiber being the most common shape (80.8 %), and transparent being the dominant color (75.3 %). Among the 13 identified polymer types, cellophane was the most prevalent. MP ingestion by fishery organisms was significantly influenced by body size, biological taxa, and habitat, while showing no correlation with feeding habits. Notably, the trophic transfer and significant biomagnification of MPs occurred through the marine food chain. Specially, MPs within the size ranges from 30 to 500 µm, in fibrous shape, transparent color, and composed of cellophane, PET, PP, and PA polymers, demonstrated enhanced potential for trophic transfer. PHI-based quantitative risk assessment revealed a medium to danger risk of MPs to marine fishery organisms, with hazard indices spanning medium to danger risk levels. These findings provide new insights into the bioaccumulation and risk of MPs across different trophic levels in marine organisms.