This study investigated the trophic transfer of microplastic from mussels to crabs. Mussels (Mytilus
edulis) were exposed to 0.5 mm fluorescent polystyrene microspheres, then fed to crabs (Carcinus maenas).
Tissue samples were then taken at intervals up to 21 days. The number of microspheres in the
haemolymph of the crabs was highest at 24 h (15 033 ml1 SE 3146), and was almost gone after 21
days (267 ml1 SE 120). The maximum amount of microspheres in the haemolymph was 0.04% of the
amount to which the mussels were exposed. Microspheres were also found in the stomach, hepatopancreas,
ovary and gills of the crabs, in decreasing numbers over the trial period. This study is the first to
show ‘natural’ trophic transfer of microplastic, and its translocation to haemolymph and tissues of a crab.
This has implications for the health of marine organisms, the wider food web and humans