Microplastics, which are accumulating in marine sediments, are assumed to pose a risk for deposit feeding
invertebrates. We tested whether the fiddler crab Uca rapax ingests and retains microplastics in its
body. Furthermore, we investigated whether retention rates depend on (a) the quality of the marine environment
in which the plastics were pre-weathered and on (b) their abundance. For this, polystyrene pellets
were submersed at a polluted and a pristine site near Niterói, Brazil, for 2 weeks. Then specimens of
U. rapax were, in laboratory experiments, exposed to fragments (180–250 lm) derived from these pellets
for 2 months. After this period, microplastics were observed in the gills, stomach and hepatopancreas of
the animals. However, fragment retention was not influenced by the two factors that we manipulated.
The presence of microplastics in different organs of the crab supports the assumption that these particles
have the potential to harm marine invertebrates