The accumulation and toxicity of ZIF-8 nanoparticles in Corbicula fluminea.

• The doses of ZIF-8 in our experiments induced similar hormesis. • ZIF-8 had significant toxic effects on benthic organism Corbicula fluminea. • The toxic effects were ascribed to nanoparticles and Zn2+ induced oxidative stress. • Low and high dosages of ZIF-8 exerted different toxicity mechanisms. • The proportion of Zn2+ and ZIF-8 in the water caused the difference in toxicity. Metal-organic frameworks (MOFs) are promising new materials that have been intensively studied and possibly applied to various environmental remediation. However, little is known about the fate and risk of MOFs to living organisms in the water environment. Here, the toxic effects of ZIF-8 nanoparticles (NPs) on benthic organisms were confirmed by sub-chronic toxicity experiments (7 and 14 days) using Corbicula fluminea as the model organism. With exposure doses ranging from 0 to 50 mg/L, ZIF-8 NPs induced oxidative stress behaviors similar to the hormesis effect in the tissues of C. fluminea. The oxidative stress induced by ZIF-8 NPs and the released Zn2+ was the crucial cause of the toxic effects. Besides, we also found that the ZIF-8 NPs and dissolved Zn2+ may result in different mechanisms of toxicity and accumulation depending on the dosages. The Zn2+ release rate of ZIF-8 NPs was high at low dosages, leading to a higher proportion of Zn2+ taken up by C. fluminea than the particulate ZIF-8. Conversely, at high dosages, C. fluminea mainly ingested the ZIF-8 NPs and resulted in increased mortality. The results have important implications for understanding the fate and biological effects of ZIF-8 in natural aquatic environments. [Display omitted] [ABSTRACT FROM AUTHOR]