Silica Nanoparticles Induce Mortality and Oxidative Stress in Ceriodaphnia reticulata (Cladocera).

ANDRADE V.S., ALE A., MUNICOY S., MORA C., BACCHETTA C., ROSSI A., DESIMONE M., GUTIERREZ M.F., CAZENAVE J.

Montevideo

Congreso; Setac Latin America 15th Biennial Meeting; 2023

Nanotechnology industry has been extensively developed in the recent years due to the unique properties of nanoproducts and their diverse applications. Nevertheless, such development has not been accompanied by ecotoxicological assessments, especially considering that aquatic systems are their main final sinks. Silica nanoparticles (SiNP) are currently one of the most produced nanomaterials under the assumption of their safety. However, the ecotoxicological studies are still incipient and their toxicity may vary according to different SiNP properties such as their size. We analyzed the effects of two sizes of SiNP (50 and 300 nm) on mortality and oxidative stress of Ceriodaphnia reticulata (Cladocera). SiNP were synthetized through Stöber method by modifying the reagents concentration according to the desired particle size. C. reticulata neonates were exposed to five concentrations (10 – 500 μg/ml) of each SiNP size and mortality was recorded at 24, 48, and 72 h. C. reticulata adults were exposed to two sublethal concentrations of each SiNP size during 72 h to assess lipid peroxidation (LPO) and the activity of antioxidant enzymes: Superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST). The lethality of the smaller SiNP (LC50 72 h: 105.5 μg/ml) was higher than the larger ones (LC50 72 h > 500 μg/ml). The 50 nm-sized SiNP increased SOD and inhibited GST activities, while larger SiNP did not exert oxidative stress under the tested concentrations. SiNP caused mortality and oxidative stress in C. reticulata despite several reports have assumed their safety. As SiNP ecotoxicity depended on their size, being the smaller ones more toxic, this study highlights the relevance of assessing the effects of different nanoparticles intrinsic properties in sensitive non-target organisms such as cladocerans. This information is crucial for regulatory purposes and contributes to the develop of safe-by-design nanoproducts to ultimately guaranteed the environment protection.