Microplastics in the edible tissues of shellfishes sold for human consumption

Microplastics in seafood are an emerging area of seafood safety concern. In this study, we investigated the presence of microplastics (100 μm - 5 mm) in the edible tissues of four species of shellfishes - two species of shrimp, Metapenaeus dobsoni and Fenneropenaeus indicus; one species of crab, Portunus pelagicus; and one species of squid Uroteuthis (Photololigo) duvaucelii -all bought from fishing harbours of Kerala, India. An average of 2.7 ± 12 microplastic particles kg of edible tissue (wet weight) and 0.07 ± 0.3 microplastic particles/individual were obtained from the sampled shellfishes. No microplastics were found in the edible tissues of shrimps examined, while U. (P) duvaucelii had the highest microplastic content with an average of 7.7 ± 20 microplastic particles kg of edible tissue, followed by P. pelagicus with an average of 3.2 ± 10 microplastic particles kg of edible tissue. There was significant species variation in the microplastic contamination of shellfish soft tissues (p < 0.05). The study is the first of its kind to report the detection of microplastics in edible tissues of a squid species. Results suggested an annual dietary intake of about 13 ± 58 microplastic particles per year by shellfish consumers, which can vary based on the species, quantity, and extent of gut removal of seafood consumed.