Bioaccumulation of Fe2O3(magnetic) nanoparticles in Ceriodaphnia dubia

While nano-Fe2O3(magnetic) is generally considered non-toxic, it could serve as a carrier of other toxic chemicals such as As(V) and enhance their toxicity. The bioaccumulation of nano-Fe2O3(m) with different exposure times, NP concentrations, and pH conditions was investigated using Ceriodaphnia dubia (C. dubia) as the model organism. Under natural pH conditions, C. dubia significantly accumulated nano-Fe2O3(m) in the gut, with the maximum accumulation being achieved after 6 h of exposure. The concentration of nano-Fe2O3 also impacted its accumulation, with the maximum uptake occurring at 20 mg/L or more. In addition, the highest bioaccumulation occurred in a pH range of 7–8 where the highest feeding rate was reported, confirming that the ingestion of NPs is the main route of nano-Fe2O3(m) bioaccumulation. In a clean environment without NPs, depuration of nano-Fe2O3(m) occurred, and food addition accelerated the depuration process.

► Nano-Fe2O3(m) enhances the toxicity of As(V).
► C. dubia significantly accumulate nano-Fe2O3(m) through ingestion.
► The bioaccumulation of nano-Fe2O3(m) is affected by time, NP concentration, and pH.
► Food addition accelerates the depuration process of accumulated nano-Fe2O3(m).