In the present study, the bivalve mollusc M. edulis was
used as a model organism to investigate the uptake, fate,
and biological consequences of ingesting microscopic particles
of polystyrene. Mussels are an important component
of benthic assemblages worldwide (9) and are thought to act
as ecosystem-engineers via occupation of primary space,
filtration, and provision of secondary habitat (10). Mytilus
edulis was selected as a model organism as it has a large
geographic range and is an important component of the diet
of various intertidal predators including humans. The
hemolymph can be easily sampled and its toxicological
responses to many contaminants are well described (11–14).
Studies examining feeding in M. edulis have shown that
microspheres of polystyrene are drawn through the inhalant
siphon and filtered via the gill. On the gill, filamentous cilia
capture plastic particles and rapidly transport them to the
ventral groove and on to the labial palps, where cilia sort
particles for ingestion or rejection as pseudofeces (15