Sodium [3-hydroxy-4-[(1-hydroxy-8-sulpho-2-naphthyl)azo]naphthalene-1-sulphonato(4-)]chromate(1-)

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Not genotoxic

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From January, 11 to February, 07 1994

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

EPA OTS 798.5265 (The Salmonella typhimurium Bacterial Reverse Mutation Test)

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9

Test concentrations with justification for top dose:

Range finding test: 20.58, 61.73, 185.19, 555.56, 1666.67, 5000.00 µg/plate mutagenicity tests: 61.7, 185.19, 555.56, 1666.67, 5000.0 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO, Bidistilled water

Untreated negative controls:

yes

Negative solvent / vehicle controls:

no

True negative controls:

no

Positive controls:

yes

Positive control substance:

cyclophosphamide

other: 2-Aminoanthracene

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium.
Inoculates from frozen master copies were set up monthly. They were grown in liquid nutrient broth medium (NB-medium) overnight and then plated on NB-agar. After incubation, single colonies were taken from the plates, grown overnight in liquid NB-medium and then used for the experiment.

Statistics:

A statistical analysis of the test data was not performed. The use of statistical methods concerning this particular test system is not generally recommended

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not determined

Vehicle controls validity:

not examined

Untreated negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Range finding test

Six concentrations of test item ranging from 20.6 to 5000.0 µg/plate were tested with strain Salmonella typhimurium TA 100 to determine the highest concentration to be used in the mutagenicity assay. The experiments were performed with and

without metabolic activation. Normal background growth was observed. The numbers of revenant colonies were not reduced. From the results obtained, the highest concentration suitable for the mutagenicity test was selected to be 5000.0 µg/plate with and without metabolic activation.

Mutagenicity test,

In the mutagenicity tests normal background growth was observed with all strains at all concentrations. The numbers of revertant colonies were not reduced. The test substance exerted no toxic effect on the growth of the bacteria.

Conclusions:

The substance and its metabolites did not induce gene mutations in the strains of Salmonella typhimurium used.

Executive summary:

The substance has been tested for mutagenic effects in vitro in histidine-requiring strains of Salmonella typhimurium according to the OECD Guideline 471 and in compliance to the GLP Pinciples.

The following strains of Salmonella typhimurium were used: TA 98, TA 100, TA 102, TA 1535 and TA 1537. The test was performed with and without the addition of rat-liver post mitochondrial supernatant (S9 fraction) as an extrinsic metabolic activation system. The compound was tested as a suspension in DMSO at five concentrations in the range of 61.7 to 5000.0 µg/plate in the presence and absence of a metabolic activation system (rat-liver post mitochondrial supernatant: S9-fraction). In order to confirm the results, the experiments were repeated with and without metabolic activation at five concentrations in the same concentration range. Each strain was additionally tested in the presence and in the absence of a metabolic activation system with a suitable, known mutagen as positive control. In both experiments, performed with and without metabolic activation, none of the tested concentrations of test substance led to an increase in the incidence of histidine-prototrophic mutants by comparison with the negative control, therefore the substance is considered as not mutagenic

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

The assessment was based on one study conducted on the substance in itself.

During the study (Huntsman, 1994), the substance was tested for mutagenic effects in vitro in histidine-requinng strains of Salmonella typhimurium according to the OECD Guideline 471 andi in compliance to the GLP Principles. The following strains of Salmonella typhimurium were used: TA 98, TA 100, TA 102, TA 1535 and TA 1537. The test was performed with and without the addition of rat-liver post mitochondrial supernatant (S9 fraction) as an extrinsic metabolic activation system.
In both experiments, performed with and without metabolic activation, none of the tested concentrations led to an increase in the incidence of histidine-prototrophic mutants by comparison with the negative control.

 

Justification for classification or non-classification

According to the CLP Regulation (EC n. 1272/2008) a mutation means a permanent change in the amount or structure of the genetic material in a cell. The term ‘mutation’ applies both to heritable genetic changes that may be manifested at the phenotypic level and to the underlying DNA modifications when known (including specific base pair changes and chromosomal translocations). The term ‘mutagenic’ and ‘mutagen’ will be used for agents giving rise to an increased occurrence of mutations in populations of cells and/or organisms.

The test substance is not capable to induce permanent mutation inside the genetic structure, therefore according to the ECHA guidance R.7a R.7.7 -1 Flow chart of the mutagenicity testing strategy, no further testing at this level are necessary and no classification is warranted according to the CLP Regulation (EC n. 1272/2008).