Impact
of Microplastic Beads and Fibers on Waterflea
(Ceriodaphnia dubia) Survival, Growth, and Reproduction:
Implications of Single and Mixture Exposures
posted on 2017-10-23, 00:00authored byShima Ziajahromi, Anupama Kumar, Peta A. Neale, Frederic D. L. Leusch
There is limited knowledge regarding
the adverse effects of wastewater-derived
microplastics, particularly fibers, on aquatic biota. In this study,
we examined the acute (48 h) and chronic (8 d) effects of microplastic
polyester fibers and polyethylene (PE) beads on freshwater zooplankton Ceriodaphnia dubia. We also assessed the acute response
of C. dubia to a binary mixture of microplastic beads
and fibers for the first time. Acute exposure to fibers and PE beads
both showed a dose-dependent effect on survival. An equitoxic binary
mixture of beads and fibers resulted in a toxic unit of 1.85 indicating
less than additive effects. Chronic exposure to lower concentrations
did not significantly affect survival of C. dubia, but a dose-dependent effect on growth and reproduction was observed.
Fibers showed greater adverse effects than PE beads. While ingestion
of fibers was not observed, scanning electron microscopy showed carapace
and antenna deformities after exposure to fibers, with no deformities
observed after exposure to PE beads. While much of the current research
has focused on microplastic beads, our study shows that microplastic
fibers pose a greater risk to C. dubia, with reduced
reproductive output observed at concentrations within an order of
magnitude of reported environmental levels.