Chronic Effects of Silver Nanoparticles on Micro-Crustacean Daphnia lumholtzi

Abstract

This study aimed to enhance our insight on the potential toxicological effects of silver nanoparticles (AgNPs) into the aquatic environment. To investigate the chronic toxicity of nanoparticles, freshwater micro-crustacean Daphnia lumholtzi was exposed to different concentrations of 0.2, 0.5 µg/l AgNPs, and control, for 21 days. Toxicological endpoints at different growing stages such as the maturation and reproduction were recorded. The reproduction rate of D. lumholtzi exposed to both AgNPs concentrations (0.2 and 0.5 µg/l ) was significantly lower than that of control. In turn, the maturation exposed to both AgNPs concentrations was not significantly different from the control treatment. This result indicates that AgNPs (with a concentration lower than 0.5 µg/l) did not have an adverse effect on the maturation of D. lumholtzi, but AgNPs with a concentration higher than 0.2 caused a toxic effect on the reproduction rate of D. lumholtzi during 21 days of the exposure period. In conclusion, the present results showed that AgNPs have toxic effects on D. lumholtzi and it has the potential to use as good freshwater aquatic zooplankton for assessment on the toxicity of nanomaterials in tropics. The future study should pay more attention to the effect of AgNPs on survival, growth rate, and multiple generations of daphnids to better understand the effects of nanoparticles in general and AgNPs in particular.