The Study of the Accumulation Characteristics of Environmental Characteristic Microplastics in Organisms at Different Trophic Levels

Microplastics are widely present in aquatic environments and, due to their high hydrophobicity, can carry organic pollutants while affecting their accumulation and toxicity in organisms at different trophic levels.The ingestion of microplastics by organisms can be divided into direct and indirect ingestion.Direct ingestion refers to organisms directly consuming microplastics present in the environmental medium, while indirect ingestion can be understood as microplastics being ingested by organisms along the transfer of trophic levels.This study aimed to determine the distribution of microplastics in the surface water of the Yangtze River Estuary and the accumulation characteristics of microplastics in organisms at different trophic levels.In 2021, the study selected typical sampling stations in the Yangtze River Estuary and its adjacent waters for observation, analyzing the concentration and characteristics of microplastics in surface water and samples from nine different trophic level organisms (two types of gastropods and seven types of fish).The abundance of microplastics in the surface water samples collected from the Yangtze River Estuary was 661.2 220.5 items/m 3 .The average abundance of microplastics in the gills of organisms was 1.1 0.4 items/g w.w., and in the gastrointestinal tract, it was 0.3 0.1 items/g w.w.Based on the calculation of the bioconcentration factor of microplastics, we found that the bioconcentration factor of higher trophic level organisms (fish) (2.6 0.5 m 3 /kg w.w.) was significantly greater than that of gastropod organisms (0.87 0.4 m 3 /kg w.w.).In terms of feeding types, the bioconcentration factor of carnivorous fish organisms was significantly greater than that of omnivorous fish.This paper determined the trophic level of organisms through stable nitrogen isotopes ( 15 N), and the biomagnification factor of microplastics was calculated to be 4.2 based on the linear regression equation of microplastic concentration and organism trophic level.Therefore, microplastic concentrations can be transferred along different trophic levels in the food chain, and the accumulation level of microplastics in organisms significantly increases with the rise of trophic levels, indicating the potential for biomagnification of microplastics in gastropods and fish organisms.