Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
no hazard identified

Marine water

Hazard assessment conclusion:
no data: aquatic toxicity unlikely

STP

Hazard assessment conclusion:
no data: aquatic toxicity unlikely

Sediment (freshwater)

Hazard assessment conclusion:
no hazard identified

Sediment (marine water)

Hazard assessment conclusion:
no hazard identified

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
no hazard identified

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
no potential for bioaccumulation

Additional information

No aquatic PNEC values were derived for silicon zirconium oxide. The argumentation for this is described below.

No adverse effects were observed in the available toxicity studies with fish and aquatic invertebrates performed with zirconium dioxide at concentrations below or equal to the limit test dose of 100 mg/L. In algal growth inhibition tests with zirconium compounds, adverse effects on growth have been observed at concentrations (slightly) below 100 mg/L. However, the observed effects were due to phosphate deprivation of the algae, as a result of strong complexation of zirconium with the phosphate in the test medium. Anyhow, all EC50 levels were > 100 mg/L. In conclusion, zirconium dioxide should not be considered as toxic or harmful to aquatic organisms.

To demonstrate the validity of the read across assumption, i.e. that the addition of silicon to the crystal lattice of zirconium dioxide does not alter the unhazardous character of zirconium dioxide, studies were performed with silicon zirconium oxide for basic (Annex VII) ecotoxicological endpoints, i.e. acute toxicity to aquatic invertebrates and toxicity to aquatic algae. In both studies, no relevant adverse effects were observed up to and including at the limit test dose of 100 mg/L (using a saturated solution with nominal loading rate of 100 mg/L), which is in agreement with the available studies for zirconium dioxide (see above).

Taking all this into account, the addition of silicon to the zirconium dioxide crystal lattice can be considered not to alter the non-hazardous properties of zirconium dioxide in the environment. The substance is therefore not classified for any environmental hazard, and no chemical safety assessment needs to be performed. Consequently, it was not considered useful to derive PNEC values for the aquatic environment. For the same reasons, no PNEC values were determined for sediment and terrestrial organisms either.

Finally, no PNEC value was determined for secondary poisoning since the available mammalian studies indicate that silicon zirconium oxide is not a hazardous substance and because there is no concern for bioaccumulation or biomagnification of silicon or zirconium from silicon zirconium oxide in both the aquatic and terrestrial environment.

Conclusion on classification

Based on the available toxicity data (fish, aquatic invertebrates, and algae) for silicon zirconium oxide and zirconium dioxide, it was concluded that there are no indications for silicon to change the non-hazardous properties of zirconium dioxide, when manufacturing silicon zirconium oxide. Therefore, as is the case for zirconium dioxide, silicon zirconium oxide is not considered to be classified for any environmental hazard either.