Microplastics in different tissues of caught fish in the artificial reef area and adjacent waters of Haizhou Bay

In recent years, the microplastics (MPs) pollution in the offshore of microplastics has gradually become a concerning topic, and the understanding the accumulation of MPs in different tissues of organisms is also an important aspect. MPs can easily affect target tissues and transport related chemicals to humans through the food chain. MPs in the gills and guts of fish in the artificial reef area of Haizhou Bay and adjacent waters were detected in this study. The results showed that MPs were ubiquitous in the gills and guts of 26 species, with average quantities of 3.54 ± 2.14 pieces/fish and 3.00 ± 2.63 pieces/fish, respectively. More than 99% of the plastics were MPs that were less than 5 mm in diameter, with blue fiber being the most common. The number and quantity of MPs in gills were higher than those in guts in different habitat types, living water layers and feeding habits of fish. At the community level, as the body length and body weight increased, the quantity of MPs in the gills and guts showed a slight decreasing trend, and the correlation was not strong (P > 0.05). With increasing trophic levels (TLs), MPs were biomagnified in the guts (Trophic magnification factor, TMF = 1.37), but no change occurred in the gills (TMF = 1.00). We believe that biomagnification of MPs should be obtained by comparing the quantity of MPs in whole organisms rather than only in specific tissues before such conclusions can be defined. We recommend that periodic marine monitoring programs be implemented, as well as research into smaller MPs and even nanoplastics, to assess from the perspective of water, sediments, organisms and ecotoxicology, which will provide useful information for MPs pollution in artificial reefs and help to improve the MPs pollution database in China.