Plastics debris is accumulating in the environment and is fragmenting into smaller
pieces; as it does, the potential for ingestion by animals increases. The consequences
of macroplastic debris for wildlife are well documented, however the impacts of microplastic
(< 1 mm) are poorly understood. The mussel, Mytilus edulis, was used to investigate
ingestion, translocation, and accumulation of this debris. Initial experiments showed
that upon ingestion, microplastic accumulated in the gut. Mussels were subsequently
exposed to treatments containing seawater and microplastic (3.0 or 9.6 microm). After
transfer to clean conditions, microplastic was tracked in the hemolymph. Particles
translocated from the gut to the circulatory system within 3 days and persisted for
over 48 days. Abundance of microplastic was greatest after 12 days and declined thereafter.
Smaller particles were more abundant than larger particles and our data indicate as
plastic fragments into smaller particles, the potential for accumulation in the tissues
of an organism increases. The short-term pulse exposure used here did not result in
significant biological effects. However, plastics are exceedingly durable and so further
work using a wider range of organisms, polymers, and periods of exposure will be required
to establish the biological consequences of this debris.