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Key value for chemical safety assessment

Additional information

Summary Genotoxicity:

Lanthanum oxide was negative in a standard bacterial gene mutation assay with S. typhimurium TA1535, 1537, 98, 100 and 102 (Sokolowsky 2006) with and without a metabolic activation system. The soluble Lanthanum derivative Lanthanum nitrate hexahydrate was also reported to be negative in a bacterial assay with S. thyphimurium strains TA100, TA1535, TA97 and TA98 (Zeiger et al., 1992), suporting the negative effect of lanthanum ions in this test system Several other mutagenicity studies are available for the lanthanum carbonate. These are considered relevant for lanthanum oxide as well due to the similarly low water solubility of both substances. Lanthanum carbonate was negative in a mammalian gene mutation assay (HPRT-locus) in Chinese Hamster Ovary cells and a bacterial gene mutation assay in TA1535, TA1537, TA1538, TA98, TA100, TA102) and E. coli WP2 uvrA and WP2 uvrA (pkm101) both with and without metabolic activation (Damment et al. 2005). An in vitro cytogenetic assay in Chinese Hamster ovary cells with lanthanum carbonate was equivocal. Apparent positive findings at some concentrations were attributed to cytotoxicity and precipitation of the test substance (Damment et al. 2005).. An in vivo oral mouse bone marrow micronucleus test in CD-1 mice with lanthanum carbonate was negative (non mutagenic) (Damment et al. 2005). Several studies have also been performed with lanthanum chloride. As a the chloride is soluble lanthanum salt these are representative for testing La3+genotoxicity. Lanthanum chloride was negative in a rat bone marrow micronucleus test after intravenous administration and in a rat liver in vivo/ex vivo UDS assay after 28-day repeated intravenous administration (Damment et al. 2005).

From the results of these tests it can be concluded that lanthanum compounds, including lanthanum oxide are not genotoxic and not clastogenic.

Short description of key information:
From available valid in vitro and in vivo data with lanthanum compounds it can be concluded that lanthanum oxide is not genotoxic and not clatogenic.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Due to the negative results in in vitro and in vivo genotoxicity studies with lanthanum compounds no classification for genotoxicity is warranted.