Relationship between the microplastics in typical marine organisms and the environment: A case study in Bohai Bay,...

Microplastics are widely distributed in the marine environment, and the impact on organisms is worthy of attention. This study focused on the Bohai Bay as the research area, aiming to gain a deeper understanding of the relationship between the distribution of microplastics in organisms and the environment as well as their feeding methods. The average abundance of microplastics in the water was 1.83 ± 0.54 items/L at 16 sampling sites in the Bohai Bay. The abundance of microplastics in different organisms and different tissues varied. The abundance of microplastics in the gastrointestinal tracts (4.4 ± 0.7 items/ind., 5.5 ± 0.2 items/g) of predatory fish was higher than that in their gills (2.2 ± 0.8 items/ind., 5.8 ± 1.0 items/g). The polymer types of microplastic in organisms were all present in seawater, including rayon, PET, polyester and PE. Fibrous microplastics were the main shape type in both seawater and organisms, accounting for more than 70.0%. Microplastics smaller than 0.5 mm accounted for the highest proportion, being 43.2% in seawater and 76.5% in organisms. The microplastics size fraction in seawater sample was basically consistent with the microplastics in wild marine organisms. In particular, the abundance, shape, size, color and polymer type distribution patterns of microplastics in filter-feeding mussels was more closely resembled those in seawater. The results revealed that the biological uptake mechanisms suggested by the tissue-specific correlations.