Long-term effect of zinc oxide nanoparticles on population growth, reproductive characteristics and zinc accumulation of marine rotifer, Brachionus plicatilis

In the present study, the effects of ZnO nanoparticles (NPs) on marine rotifer, Brachionus plicatilis, was investigated in three separate experiments. Firstly, the sensitivity and reproductive characteristics of B. plicatilis were studied at concentrations of 0, 0.1, 0.5, 1, 3, 5 and 10 mg L-1 of ZnO-NPs for 10 days. Based on the results, the total number of rotifers (TNR) significantly decreased at 5 and 10 mg L-1 of ZnO-NPs. In addition, the specific growth rate (SGR) of animals was negative at two of the concentrations of ZnO-NPs. In the second experiment, the TNR at 4 concentrations of ZnO-NPs (0, 10, 13, 17, and 19 mg L-1) during 72 h were tested and the 24-72 h LC50 of ZnO-NPs was calculated. After three days, the entire population of rotifers was generally lost at 19 mg L-1 of ZnO NPs. The LC50 of ZnO-NPs in animals at 24, 48, and 72 h intervals was registered as 18.2±1.34, 12.43±0.08, and 9.63±0.26 mg L-1, respectively. Finally, the zinc accumulation in rotifers was measured at different concentrations (0, 0.1, 0.5, and 1.3 mg L-1) of ZnO-NPs and maximum zinc (123 μg g-1 of rotifer DW) uptake by rotifers was observed in treatment 3 mg L-1 of ZnO-NPs. In sum, it can be concluded that the B. plicatilis can be used as a biological model for studying marine water contaminants with nanoparticles, especially ZnO-NPs.