a b s t r a c t
Suspended particles are a natural component of aquatic ecosystems. This study provides a report on the
survival, growth and reproduction of common-scale and nanoscale particles of Daphnia magna Straus
exposed to five types of particles (i.e. KN (kaolinite), MN (montmorillonite), MNn (nanoscale MN), NP
(natural particles), and NPn (nanoscale NP)). The results of the study show that the suspended particles
elicited a dose-dependent toxicity in KN, MN and MNn, with the following toxicity pattern:
MN > KN > MNn. On the contrary, NP and NPn did not show any harmful effects on the animals. Instead,
NP and NPn, especially NPn, contributed to the survivorship of the animals. The animals were able to survive
throughout the 21-day period of bioassays, and when the particle concentration reached 600 mg L1,
they produced many neonates without any addition of food. This experimental results also indicated that
the nanoscale particles were less toxic than the common-scale ones, both for MN and NP. Moreover, the
results of the 21-day period of bioassays indicated that when the organisms were exposed to particles of
different size scales, they showed different selection patterns for allocating resources. This may be due to
the generation of different assimilation and digestion patterns.