Niobium hydride

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Ames, Micronucleus and Mammalian Gene Mutation Studies

Due to the physical properties of the test material it is not possible to perform the Salmonella typhimurium Reverse Mutation Assay, the Escherichia coli Reverse Mutation Assay, the in vitro micronucleus study or the mammalian gene mutation study.

Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro cytogenicity / micronucleus study

Data waiving:

study technically not feasible

Justification for data waiving:

other:

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
The performance of the micronucleus study was not technically feasible due to the physical properties of the test material.
The test material was a silver grey solid, it was grounded with a mortar and pestle to obtain a powder before the solubility test was performed. The test material did not dissolve in the commonly used solvents dimethyl sulfoxide and ethanol nor could a homogeneous suspension be obtained at concentrations of 93.91, 50 and 5 mg/mL. All formulations were treated with ultrasonic waves for at least 43 minutes. At concentrations of 93.91 and 50 mg/mL a non-homogenous suspension was obtained with test material on the bottom of the test tube. At the concentration of 5 mg/mL a colourless solution with test material on the bottom was obtained. No homogeneous suspension or solution could be obtained with acetone, tetrahydrofuran, dimethylformamide and hexane at a concentration of 10 mg/mL. All formulations were treated with ultrasonic waves for at least 18 minutes. All formulations were again colourless solutions with test material on the bottom of the test tube.
Therefore it was concluded that due to the physical properties of the test material it was not possible to perform the in vitro micronucleus study.

Reference 2

Endpoint:

in vitro gene mutation study in bacteria

Data waiving:

study technically not feasible

Justification for data waiving:

other:

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
The performance of the bacterial reverse mutation assay was not technically feasible due to the physical properties of the test material.
The test material was a silver grey solid. It was grounded with a mortar and pestle to obtain a powder before the solubility test was performed. The test material did not dissolve in the commonly used solvents dimethyl sulfoxide and ethanol nor could a homogeneous suspension be obtained at concentrations of 93.91, 50 and 5 mg/mL. All formulations were treated with ultrasonic waves for at least 43 minutes. At concentrations of 93.91 and 50 mg/mL a non-homogenous suspension was obtained with test material on the bottom of the test tube. At the concentration of 5 mg/mL a colourless solution with test material on the bottom was obtained. No homogeneous suspension or solution could be obtained with acetone, tetrahydrofuran, dimethylformamide and hexane at a concentration of 10 mg/mL. All formulations were treated with ultrasonic waves for at least 18 minutes. All formulations were again colourless solutions with test material on the bottom of the test tube.
Therefore it is concluded that due to the physical properties of the test material it is not possible to perform the Salmonella typhimurium Reverse Mutation Assay and the Escherichia coli Reverse Mutation Assay.

Reference 3

Endpoint:

in vitro gene mutation study in mammalian cells

Data waiving:

study technically not feasible

Justification for data waiving:

other:

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
The performance of the mammalian gene mutation study was not technically feasible due to the physical properties of the test material.
Due to the insolubility of the substance and the fact it cannot form a suspension the test will not be technically feasible even if testing was to be performed with the the powder form of the substance.
In addition taking account the physical form that the substance is only ever manufactured in there is a strong argument that exposure to workers or the general public to the test substance is not possible and that coupled with the expected extremely low solubility means the substance will also not be bioavailable.

Endpoint conclusion

Endpoint conclusion:

no study available

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Ames, Micronucleus and Mammalian Gene Mutation Studies

The performance of the bacterial reverse mutation assay and micronucleus study were not technically feasible due to the physical properties of the test material.

The test material was a silver grey solid, it was grounded with a mortar and pestle to obtain a powder before the solubility test was performed. The test material did not dissolve in the commonly used solvents dimethyl sulfoxide and ethanol nor could a homogeneous suspension be obtained at concentrations of 93.91, 50 and 5 mg/mL. All formulations were treated with ultrasonic waves for at least 43 minutes. At concentrations of 93.91 and 50 mg/mL a non-homogenous suspension was obtained with test material on the bottom of the test tube. At the concentration of 5 mg/mL a colourless solution with test material on the bottom was obtained. No homogeneous suspension or solution could be obtained with acetone, tetrahydrofuran, dimethylformamide and hexane at a concentration of 10 mg/mL. All formulations were treated with ultrasonic waves for at least 18 minutes. All formulations were again colourless solutions with test material on the bottom of the test tube.

Therefore it is concluded that due to the physical properties of the test material it is not possible to perform the Salmonella typhimurium Reverse Mutation Assay, the Escherichia coli Reverse Mutation Assay, the in vitro micronucleus study or the mammalian gene mutation study.