Lanthanum(3+) acetate

Endpoint summary

Additional information

Genetic toxicity in vitro:

Bacterial reverse mutation assay:

Thompson (2013) performed an Ames test (OECD 471; EU B.13/14 and EPA OPPTS 870.5100) with S. typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and E. coli strain WP2 uvrA with and without metabolic activation.

Following test concentrations were applied in triplicate: 50, 150, 500, 1500, 5000 µg/plate for experiment 1 and 5, 15, 50, 150, 500, 1500, 5000 µg/plate for experiment 2. Negative controls and positive controls were run in triplicate and were considered to be valid. According to the results of the study, the test substance is not mutagenic in the Ames with and without metabolic activation.

Chromosome Aberration:

Bowles (2013) performed an in vitro Chromosome Aberration test in human lymphocytes (OECD 473). Two experiments were performed using different test concentrations with and without S9 activation (4h or 24h exposure; 20h expression period). Both negative and positive controls were considered to be valid. In both experiments lanthanum acetate considered not to induce any significant increases in the frequency of cells with aberrations, which included at least one precipitating dose level, either in the absence or presence of metabolic activation. Therefore, lanthanum acetate was considered to be non-clastogenic.

In vitro mammalian cell gene mutation:

Morris (2013) performed a CHO hprt forward mutation assay, targeting the HPRT locus of Chinese hamster ovary (CHO) cells, according to OECD 476. The technique used is a plate assay using tissue culture flasks and 6-thioguanine (6-TG) as the selective agent. CHO cells were treated with the test item at up to 8 dose levels, together with solvent (dimethyl sulphoxide) and positive controls (ethyl methane sulphonate). Four treatment conditions (4h or 24h exposure, with or without metabolizing system, 1% or 2% final concentration) were used in 2 experiments. The vehicle and positive control were considered to be valid and the test item did not demonstrate dose related increases in mutant frequency either with or without metabolic activation, either in the first or the second experiment. Therefore, the test item was considered to be non-mutagenic to CHO cells at the HPRT locus under the conditions of this test. 

Genetic toxicity in vivo:

According to REACH Annex IX section 8.4, column 2, no further in vivo testing is required as no positive results were obtained in any of the three in vitro studies performed according to REACH Annexes VII and VIII section 8.4.

Justification for selection of genetic toxicity endpoint
One study cannot be selected as there are 3 in vitro key studies available.

Short description of key information:
Genetic toxicity in vitro:
Bacterial reverse mutation assay: performed according to OECD Guideline 471 in S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2 uvr A (Thompson, 2013). The test item was not mutagenic with and without metabolic activation.
In vitro mammalian chromosome aberration test: performed according to OECD Guideline 473 and EU Method B.10 in human lymphocytes (Bowles 2013). The substance was not clastogenic in the absence and presence of metabolic activation.
In vitro mammalian cell gene mutation test: CHO hprt forward mutation assay performed according to OECD Guideline 476 and targeting the HPRT locus of Chinese hamster ovary (CHO) cells (Morris 2013). The test item was not mutagenic under the experimental conditions in the absence and presence of metabolic activation.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the available data and according to the criteria of the CLP Regulation (EC) 1272/2008, lanthanum acetate should not be classified for mutagenicity.