Microplastics in the muscle of marine fish from coastal China: occurrence and characteristics

Introduction: Microplastics in fish muscle are relevant to seafood-related human exposure, but data on their occurrence and characteristics remain limited, particularly across coastal regions of China. This study investigated microplastic contamination in the muscle of marine fish and estimated dietary exposure in the Chinese population.

Methods: A total of 131 marine fish representing 19 species were collected from the Bohai Sea, East China Sea, and South China Sea. Microplastics in muscle within the 10–500 μm size range were extracted and identified using laser direct infrared imaging. Dietary exposure was estimated using the mean microplastic concentration in muscle combined with individual marine fish consumption data from Chinese food consumption surveys.

Results: Microplastics were detected in the muscle of 125 of 131 fish (95.4%). The mean, median, and range of microplastic abundance in muscle were 19.31, 12.96, and 0.00–97.83 items/g, respectively. Particles <100 μm accounted for 90.7% of detected microplastics, with the 20–50 μm fraction being predominant. Fragments were the most abundant shape category (48.2%), and polyvinyl chloride was the dominant polymer (42.7%). For the 10–500 μm fraction, the mean and 95th percentile dietary exposures were 2.78 and 19.54 items/kg body weight/day in the general population, and 20.25 and 53.64 items/kg body weight/day in marine fish consumers, respectively.

Conclusions: Microplastics were prevalent in the muscle of marine fish from coastal China, and the marine fish consumption constituted a source for dietary microplastics exposure. The data on microplastics contamination characteristics and dietary exposure may support the future seafood-related microplastic assessment.