Existence of microplastics in the edible part of the sea cucumber Apostichopus japonicus

Microplastics (MPs; <= 5 mm) have become a potential threat to human health due to the widespread detection of MPs in foods consumed by humans. Here, we investigated the potential of MP occurrence in the main edible part of the most valuable species of sea cucumbers (Apostichopus japonicus). Laboratory experiments showed that fluorescent MPs and microfibers (MFs) could transfer into the body wall of the sea cucumber. The evidence revealed that these MPs enter the body wall via the outer surface. Although these MPs decreased after the sea cucumbers were transferred to clean water, traces of MPs (at least one MP particle) were found up to 60 d posttransfer. To validate these laboratory observations, sea cucumber samples were collected from the field. MPs were found in 86% of live and processed sea cucumber samples. The MP abundances in the field samples ranged from 0-15 MPs animal-1 and 0-2 MP g-1. The isolated MPs were mainly MFs, constituting 81% of MPs, followed by fragments, films, and beads. Fourier transform infrared spectroscopy revealed that the polymer composition of the isolated MPs mainly included rayon, followed by polyester and chlorinated polyethylene. The findings of this study demonstrated that the body walls of farmed and processed sea cucumbers contain MPs, thus highlighting the need to control MP pollution during the farming and processing of sea cucumbers.

Automated summary

Laboratory experiments showed that microplastics and microfibers can transfer into the body wall of sea cucumbers, entering through the outer surface. In samples collected from the field, 86% of sea cucumbers were found to contain microplastics, mainly in the form of microfibers. The need to control microplastic pollution during the farming and processing of sea cucumbers was emphasized based on the findings of this study.