Microplastic accumulation and histological effects on the Atlantic deep-sea scale-worm Laetmonice filicornis.

Small benthic scavengers and carnivores, such as polychaetes, are very interesting to assess the accumulation and transfer of microplastics (MPs) to higher trophic levels in marine ecosystems. In this study we evaluate the presence, accumulation and impacts of MPs in the North-Atlantic deep-sea polychaete Laetmonice filicornis. Three types of MPs were identified: fishing lines, fibres and fragments, mostly black in colour, followed by red and blue ones. The average number of MPs was 4.10 ± 1.90 particles/g tissue. Fibres were the most abundant. They were composed of Polypropylene, Rayon, Polyethyleneimine Cellulose and Polyester. The histological analysis revealed the presence of microfibres embedded in muscles, peritoneum, nephridia, gonads and blood vessels, which can have a direct impact on vital functions, such as feeding and reproduction. This species occupies both predator and prey roles, bioaccumulate MPs and can transfer them to higher trophic links, representing a significant threat to all marine species, including humans.