Zirconium oxide, hafnium and ytterbium doped

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

In line with Annex XI, section 1.2 of Regulation (EC) 1907/2006, conducting a study to assess the toxicity of reproduction with zirconium oxide, hafnium and ytterbium doped (target substance) is scientifically not necessary. Due its low solubility and bio-accessibility a toxicity to reproduction of the target substance is not expected. The insolubility of the target substance was confirmed by a Transformation/dissolution assay (see IUCLID section 4.8). Hafnium and zirconium was not detectable. For ytterbium, an average metal release of 0.069 µg/L was measured after 7 days at 100 mg/L mass loading. To evaluate the bio-accessibility of the target substance a bio-elution test was conducted (see IUCLID section 7.1.1). The highest metal release values were found in artificial lysosomal fluid with a metal release for Yb of 8.314 µg/L, for Zr of 4.30 µg/L and for Hf of 0.02 µg/L (which is actually the limit of quantification). For the oral and dermal route, the metal release of hafnium was below the detection limit, for Yb within the range of 0.485 to 3.24 µg/L and for Zr within 0.01-0.02 µg/L. Thus, the bioavailability of the target substance can be expected to very low. Furthermore, a weight of evidence approach based on ytterbium oxide and ytterbium chloride as ytterbium based substances is established to determine the toxicity to reproduction of YbHfZrO. Based on the results of both source substances and due to the low solubility and bio-accessibility a toxicity to reproduction induced by the target substance is not expected.

Link to relevant study records

Reference

Reference 1

Endpoint:

screening for reproductive / developmental toxicity

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Reference 2

Endpoint:

extended one-generation reproductive toxicity - basic test design (Cohorts 1A, and 1B without extension)

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Effect on fertility: via oral route

Endpoint conclusion:

no study available

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Effects on developmental toxicity

Description of key information

In line with Annex XI, section 1.2 of Regulation (EC) 1907/2006, conducting a study to assess the developmental toxicity with zirconium oxide, hafnium and ytterbium doped (target substance) is scientifically not necessary. Due its low solubility and bio-accessibility, developmental toxicity of the target substance is not expected. The insolubility of the target substance was confirmed by a Transformation/dissolution assay (see IUCLID section 4.8). Hafnium and zirconium was not detectable. For ytterbium, an average metal release of 0.069 µg/L was measured after 7 days at 100 mg/L mass loading. To evaluate the bio-accessibility of the target substance a bio-elution test was conducted (see IUCLID section 7.1.1). The highest metal release values were found in artificial lysosomal fluid with a metal release for Yb of 8.314 µg/L, for Zr of 4.30 µg/L and for Hf of 0.02 µg/L (which is actually the limit of quantification). For the oral and dermal route, the metal release of hafnium was below the detection limit, for Yb within the range of 0.485 to 3.24 µg/L and for Zr within 0.01-0.02 µg/L. Thus, the bioavailability of the target substance can be expected to very low. Furthermore, a weight of evidence approach based on ytterbium oxide and ytterbium chloride as ytterbium based substances is established to determine the developmental toxicity of YbHfZrO. Based on the results of both source substances and due to the low solubility and bio-accessibility, developmental toxicity induced by the target substance is not expected.

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Species:

rat

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Justification for classification or non-classification

In line with Annex XI, section 1.2 of Regulation (EC) 1907/2006, conducting a study to assess the toxicity to reproduction with zirconium oxide, hafnium and ytterbium doped (target substance) is scientifically not necessary. Due its low solubility and bio-accessibility a toxicity to reproduction of the target substance is not expected. The insolubility of the target substance was confirmed by a Transformation/dissolution assay (see IUCLID section 4.8). Hafnium and zirconium was not detectable. For ytterbium, an average metal release of 0.069 µg/L was measured after 7 days at 100 mg/L mass loading. To evaluate the bio-accessibility of the target substance a bio-elution test was conducted (see IUCLID section 7.1.1). The highest metal release values were found in artificial lysosomal fluid with a metal release for Yb of 8.314 µg/L, for Zr of 4.30 µg/L and for Hf of 0.02 µg/L (which is actually the limit of quantification). For the oral and dermal route, the metal release of hafnium was below the detection limit, for Yb within the range of 0.485 to 3.24 µg/L and for Zr within 0.01-0.02 µg/L. Thus, the bioavailability of the target substance can be expected to very low. Furthermore, a weight of evidence approach based on ytterbium oxide and ytterbium chloride as ytterbium based substances is established to determine the toxicity to reproduction of YbHfZrO. Based on the results of both source substances and due to the low solubility and bio-accessibility classification for reproductive/developmental toxicity is not warranted.