The retention of Zr from potential therapeutic silica-zirconia core–shell nanoparticles in aquatic organisms

Abstract Model experiments under laboratory conditions were carried out to assess the accumulation tendency of Zr from a silica-zirconia core–shell nanoparticles, synthesised for the assay. Acute exposition tests were conducted with Daphnia magna and Danio rerio and the accumulation tendency of the nano and the molecular form was compared. Significant elevation of Zr was found in the tissue of the test organisms treated by the NP compared to the control, however, the retention of zebrafish was lower than that of the daphnids. Increased level of bioconcentration factor and the strong correlation of the redundancy analysis data suggest accumulation tendency in D. magna, yet long-term experiments are required to prove and further assess the environmental risk of food-chain bioconcentration. The BCF results were under the REACH limit for the D. rerio groups indicating the low short-term accumulation tendency of Zr from the NP. However, Zr level was significantly higher in zebrafish individuals originating from the SiO2@ZrO2 NP exposed treatments compared to the groups supplemented by the same concentration of ZrOCl2, which did not result in the elevation of Zr in fish tissue. The trace element homeostasis of D. rerio was not affected by the acute SiO2@ZrO2 NP exposition and no lethality occurred.