Black HM 2482

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

- In vitro gene mutation study in bacteria (with and without metabolic activation): negative
- In vitro mammalian cells Chromosome aberration (with and without metabolic activation): negative
- In vitro gene mutation study in mammalian cells (with and without metabolic activation): negative

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Description of key information

In vivo mammalian cells Chromosome aberration: negative

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

A Bacterial Reverse Mutation Test, performed with and without metabolic activation, is available on the test substance. Experiments were carried out using S. typhimurium strains TA 98, TA 100, TA 1535, TA 1537 and TA 1538.The test article was tested at the following concentrations: 1.58, 5, 15.8, 50, 158, 500, 1580 and 5000 micrograms per plate. Each concentration, including the controls, was tested in triplicate. No toxic effect of the test article was observed. Up to the highest investigated dose, no relevant incerase of the revertant colony numbers was obtained in any Salmonella typhimurium strain used when compared with the corresponding controls. The presence of liver microsomal activation did not influence these findings.

 

An in vitro mammalian cells Chromosome aberration on the test substance is available. The test item dissolved in culture medium, was assessed for its potential to induce structural chromosome aberrations in V79 cells of the Chinese hamster in vitro in the absence and the presence of metabolic activation by S9 mix. Two independent experiments were performed. ln experiment l, the exposure period was 4 hrs with and without metabolic activation. In experiment ll the exposure period was 4 hrs with S9 mix and 18 hrs and 28 hrs without S9 mix. In both experiments, in the absence and the presence of S9 mix, no biologically relevant increase in the number of cells carrying structural chromosome aberrations was observed. In both experiments, no biologically relevant increase in the rate of polyploid metaphases was found after treatment with the test item (1.1 - 3.6 %) as compared to the rates of the negative controls (1.5 - 3.2 %). In conclusion, it can be stated that under the experimental conditions the test item did not induce structural chromosome aberrations in V79 cells (Chinese hamster cell line) when tested up to clearly precipitating concentrations.

 

An in vitro gene mutation study in mammalian cells is available on the test substance. The test item was tested in a Mammalian Cell Gene Mutation Test (HPRT test) in CHO-K1 cells according to OECD Guideline 476, to determine whether the test item or its metabolites can induce forward mutation at the hypoxanthine-guanine phosphoribosyl transferase enzyme locus (hprt) in cultured Chinese hamster cells. The concentration levels for the performed Mutation Assay (with and without S9-mix) were 250, 500, 1000, 1500 and 2000 μg/mL. In conclusion, test item tested up to the maximum recommended concentration (2000 μg/mL) without and with metabolic activation system over a 5-hour treatment period did not induce statistically and biologically significant increases in mutant frequency compared to the solvent control.

 

An in vivo mammalian cells Chromosome aberration experiment was performed to assess the potential mutagenic activity induced by test substance through damage to the chromosomes of to the mitotic apparatus according to Schmid (1) with the modifications of Salomone et al. (2). The test groups received 5000 mg/kg bw as the maximurn tolerated dose of the test article. After single application of the test article at 5000 mg/kg bw by gavage, no significant test article-related increase of micronucleated polychromatic erythrocytes was observed in either male and female treated groups, when compared with corresponding negative control groups. In conclusion, it can be stated that under the extrerimental conditions reported, the test article induced no chromosome mutations by chromosome-breaking activity or by damage to the mitotic apparatus. Therefore, test article is not considered to be mutagenic in this in vivo mouse micronucleus assay.

Justification for classification or non-classification

According to the CLP Regulation (EC) No. 1272/2008, for the purpose of the classification for germ cell mutagenicity, substances are allocated in one of two following categories:
- substances known to induce heritable mutations or to be regarded as if they induce heritable mutations in the germ cells of humans or substances known to induce heritable mutations in the germ cells of humans or
- substances, which cause concern for humans owing to the possibility that they may induce heritable mutations in the germ cells of humans.

 

The test substance did not show any reason of concern in all in vitro and in vivo tests performed. Therefore, the substance is not classified for genetic toxicity according to the CLP Regulation (EC) No. 1272/2008.