posted on 2023-12-19, 20:06authored byYue-Yue Liu, Wei Pan, Mei Wang, Ke-Da Zhang, Hong-Jie Zhang, Bin Huang, Wei Zhang, Qiao-Guo Tan, Ai-Jun Miao
Aquatic environments are complicated
systems that contain
different
types of nanoparticles (NPs). Nevertheless, recent studies of NP toxicity,
and especially those that have focused on bioaccumulation have mostly
investigated only a single type of NPs. Assessments of the environmental
risks of NPs that do not consider co-exposure regimes may lead to
inaccurate conclusions and ineffective environmental regulation. Thus,
the present study examined the effects of differently sized silica
NPs (SiO2 NPs) on the uptake of iron oxide NPs (Fe2O3 NPs) by the zooplankton Daphnia
magna. Both SiO2 NPs and Fe2O3 NPs were well dispersed in the experimental medium
without significant heteroaggregation. Although all three sizes of
SiO2 NPs inhibited the uptake of Fe2O3 NPs, the underlying mechanisms differed. SiO2 NPs smaller
than the average mesh size (∼200 nm) of the filtering apparatus
of D. magna reduced the accumulation of Fe2O3 NPs through uptake competition, whereas larger SiO2 NPs inhibited the uptake of Fe2O3 NPs
mainly by reducing the water filtration rate of the daphnids. Overall,
in evaluations of the risks of NPs in the natural environment, the
different mechanisms underlying the effects of NPs of different sizes
on the uptake of dissimilar NPs should be considered.