Zirconium oxide, erbium and yttrium doped

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the substance is highly insoluble in water, hence indicating that aquatic toxicity is unlikely to occur

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
The structurally similar read across substance, erbium gadolinium yttrium zirconium oxide, is practically insoluble in water. The substance is considered to be a suitable substitute for the registered substance since the only difference between the substance being registered and the read-across substance is that the substance to be registered is missing the gadolinium oxide content (about 1.4%). The absence of this compound at such a low % is considered highly unlikely to affect its properties.
The water solubility of the read-across substance was determined according to the column elution method. During the study, zirconium was measured because it is the dominant element in the material. Of the other elements, only erbium was measured, because based on comparison of the relative presence of erbium, gadolinium and yttrium in the material, as well as comparison of the water solubility of their oxide forms, erbium was concluded to be the element that would likely be released the most (if any) from the substance when added to water. However, both zirconium and erbium concentrations were below the LOQ (< 0.001 mg/L) in all samples analysed. Therefore the read across substance can be considered as insoluble in water and, consequently, not presenting any hazards to aquatic invertebrates.
By analogy, it can therefore be concluded that the substance being registered can be considered as insoluble in water and, consequently, not presenting any hazards to aquatic invertebrates.
Based on these results, there is no need to perform toxicity tests with aquatic invertebrates. It should be noted that no adverse effects have been observed in aquatic invertebrates so far when exposed to zirconium dioxide, erbium oxide or yttrium oxide. Consequently, all three inorganic oxides are not classified for the aquatic environment. Altogether, it can be safely concluded that zirconium oxide, erbium and yttrium doped does not need to be classified for the aquatic environment either.

Description of key information

In accordance with Column 2 of REACH Annex VII, information requirement section 9.1.1, this study does not need to be conducted since the substance is highly insoluble in water.

Additional information

The structurally similar read across substance, erbium gadolinium yttrium zirconium oxide, is practically insoluble in water. The substance is considered to be a suitable substitute for the registered substance since the only difference between the substance being registered and the read-across substance is that the substance to be registered is missing the gadolinium oxide content (about 1.4%). The absence of this compound at such a low % is considered highly unlikely to affect its properties.

The water solubility of the read-across substance substance was determined according to the column elution method. During the study, zirconium was measured because it is the dominant element in the material. Of the other elements, only erbium was measured, because based on comparison of the relative presence of erbium, gadolinium and yttrium in the material, as well as comparison of the water solubility of their oxide forms, erbium was concluded to be the element that would likely be released the most (if any) from the substance when added to water. However, both zirconium and erbium concentrations were below the LOQ (< 0.001 mg/L) in all samples analysed. Therefore the read across substance can be considered as insoluble in water and, consequently, not presenting any hazards to aquatic invertebrates.

By analogy, it can therefore be concluded that the substance being registered can be considered as insoluble in water and, consequently, not presenting any hazards to aquatic invertebrates.

Based on these results, there is no need to perform toxicity tests with aquatic invertebrates. It should be noted that no adverse effects have been observed in aquatic invertebrates so far when exposed to zirconium dioxide, erbium oxide or yttrium oxide. Consequently, all three inorganic oxides are not classified for the aquatic environment. Altogether, it can be safely concluded that zirconium oxide, erbium and yttrium doped does not need to be classified for the aquatic environment either.