Registration Dossier
Registration Dossier
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EC number: 234-373-8 | CAS number: 11129-15-0
Ecotoxicological Summary
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 calcium 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. Because calcium oxide rapidly reacts with water to form calcium hydroxide, data on the toxicity of calcium hydroxide to fish and aquatic invertebrates were considered next to those for zirconium dioxide to evaluate the potential hazards of calcium zirconium oxide to the environment. The adverse effects observed in the available tests with calcium hydroxide at concentrations below 100 mg/L were concurrent with a sharp increase in pH, initial pH being > 10 at test concentrations close to the reported EC50 values. Because the observed effects are not due to exposure to calcium (an essential and internally regulated element, present at concentrations within its typical environmental background range at the EC50 for fish and aquatic invertebrates), and because the limited release of calcium from calcium zirconium oxide as observed by Eidam (2014, 2015) in water is not expected to result in a substantial pH increase nor in a substantial increase in calcium levels in the aquatic environment, calcium zirconium oxide is concluded not to be toxic or harmful to fish and aquatic invertebrates.
In algal growth inhibition tests with zirconium compounds as well as with calcium hydroxide, adverse effects on growth have been observed at concentrations (slightly) below 100 mg/L. However, for zirconium dioxide, 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. For calcium hydroxide on the other hand, the observed effects were due to adherence of algal cells to precipitates formed during the test (most likely calcium carbonate). In both cases the observed effects were not direct effects of the elements (Zr, Ca) under consideration, but secondary effects of which the relevance in the environment could be questioned. Moreover, since all EC50 levels obtained in the available tests were > 100 mg/L, zirconium dioxide nor calcium hydroxide are considered to be toxic or harmful to algae.
Taking all this into account, the addition of calcium oxide to zirconium dioxide 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. Consquently, 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 zirconium dioxide nor calcium oxide is a hazardous substance and because there is no concern for bioaccumulation or biomagnification of zirconium dioxide or calcium oxide in both the aquatic and terrestrial environment.
Conclusion on classification
Based on the available toxicity data (fish, aquatic invertebrates, and algae) for the individual compounds zirconium dioxide and calcium oxide (data for calcium hydroxide are considered instead because calcium oxide rapidly reacts with water to form calcium hydroxide in the environment), it was concluded that there are no indications for calcium oxide to change the non-hazardous properties of zirconium dioxide, when manufacturing calcium zirconium oxide.
Therefore, as is the case for zirconum dioxide, calcium zirconium oxide is not considered to be classified for any environmental hazard either.Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
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