Acute Toxicity of Colloidal Silicon Dioxide Nanoparticles on Amphibian Larvae: Emerging Environmental Concern

LAJMANOVICH R.C., ; PELTZER P.M., ; MARTINUZZI C.S.,; ATTADEMO A.M.,; COLUSSI C.L.,; BASSÒ A.

INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH

UNIV TEHRAN

Lugar: Tehran; Año: 2018 vol. 12 p. 269 - 278

1735-6865

Emerging contaminants derive from pharmaceuticals, pesticides, disinfection by-products, home and care products, andwood preservation and industrial chemicals that contain specific drugs, metals, metal oxides and metalloids as nanoparticles(NPs) in their formulations. Although the use of silicon dioxide (SiO2) NPs in commercial products increases, itsimpacts on the environment and on animal and human health are largely unknown. Thus, the aim of this study was toevaluate the ecotoxicity of colloidal SiO2-NPs in Rhinella arenarum larvae exposed to 0.001, 0.01, 0.1, and 1 mg/Lcolloidal SiO2-NPs for 48 h. Biotoxicological endpoints (median lethal concentration-LC50; 95% confidence limits), theno-observed-effect concentration (NOEC), the lowest-observed-effect concentration (LOEC), Toxic Units (TU), oxidativestress enzyme activity (glutathione S-transferase-GST), and genotoxicity (frequency of micronuclei, and other erythrocytenuclear abnormalities-ENAs) were measured in exposed larvae. Scanning electron microscopy equipped with an energydispersive X-ray system allowed detecting that SiO2-NPs aggregate on the dorsal skin of SiO2-treated larvae. The 48 hLC50 of colloidal SiO2-NPs was 0.0251 mg/L (0.0163- 0.0338 mg/L). The NOEC and LOEC values after 48 h were0.001 mg/L and 0.01 mg/L, respectively. According to the hazard classification system for wastewaters discharged into theaquatic environment, the colloidal SiO2-NPs evaluated are Class V, i.e., of very high acute toxicity (TU = 3984.06). At48 h of exposure to NOEC, GST activity and ENAs frequency were significantly increased (118.75 and 58%, respectively)with respect to controls. The results of the present study indicate that, at low concentration, colloidal SiO2-NPs exertedhigh toxicity on R. arenarum tadpoles.