Lanthanum nitrate genotoxicity evaluation: Ames test, mouse micronucleus assay, and chromosome aberration test

- Genotoxicity of Lanthanum nitrite (LaN) was comprehensively characterized through a battery of in vitro and in vivo tests.
- LaN was not mutagenic to bacterial cells in Ames test.
- LaN did not increase the bone marrow micronucleus and chromosome aberration in the mouse after repeated oral exposure.
- LaN did not increase the frequency of chromosome aberration in CHO cells in vitro.
- Lanthanum is not of potent genotoxic hazard to human under oral exposure.

The increasing use of rare-earth elements (REE) and their compounds has led to their accumulation in the environment and has raised concern about their safety. The toxic effects of REE such as lanthanum are largely unknown; genotoxicity studies have been limited and results are controversial. We evaluated the genotoxicity of lanthanum nitrate (La(NO3)3) in several in vitro and in vivo tests, including bacterial reverse mutation assay (Ames test), mouse bone marrow micronucleus assay, and chromosome aberration assay. La(NO3)3 was not mutagenic in the Ames test. La(NO3)3 did not increase the frequencies of bone marrow micronuclei or chromosome aberration in the mouse after repeated treatments at oral doses up to 735 (females) and 855 mg/kg (males). The compound did not increase the frequency of chromosome aberrations in CHO cells in vitro. These results indicate that lanthanum is not a genotoxic hazard.