Bioaccumulation, Biopersistence, and Toxicity of CMP Nanoparticles in Mammalian and Aquatic Models
Research Report Highlight
Researchers report on: (1) Chronic toxicity of four pristine model CMP slurries on Daphnia magna. (2) Bioaccumulation of pristine ceria and alumina slurries in macrophages. (3) Acute toxicity of the four pristine model slurries on Tetrahymena pyriformis.
Chronic effects on mortality, body size, and reproduction after a 21-day exposure to c-silica, f-silica, ceria, and alumina CMP nanoparticles (NPs) at a concentration of 0.1 mg/mL were assessed with Daphnia magna. C-silica, f-silica, and ceria did not cause significant mortality in Daphnia whereas alumina caused ~70% mortality. C-silica, f-silica, and ceria did not reduce body size. Alumina reduced the average Daphnia body size moderately by ~18% compared to controls. C-silica and f-silica had little effect on Daphnia reproduction whereas ceria and alumina severely reduced Daphnia reproduction by 86% and 76%, respectively. These data suggest that different model CMP slurries exert different and unpredictable adverse effects on Daphnia magna. Especially important is that ceria affected neither mortality nor body size but severely reduced Daphnia reproduction, which could have serious consequences in aquatic ecosystems and warrants further study.
To assess bioaccumulation of ceria and alumina in mouse macrophage RAW 264.7 cells, the cells were exposed to NPs at various concentrations for 2 days at 37 °C and washed extensively. Cell-associated ceria and alumina were quantified by ICP-MS. Both ceria and alumina accumulated in macrophages and these amounts increased as a function of the applied dose.
The toxicity of c-silica, f-silica, ceria, and alumina was assessed with Tetrahymena pyriformis after a 24-h exposure. Ceria had no significant effect on Tetrahymena growth at concentrations up to 2 mg/mL. Alumina and c-silica caused slight reduction in Tetrahymena growth at concentrations >1 mg/mL. F-silica caused a dose-dependent reduction in Tetrahymena growth that reached 50% at 2 mg/mL.