Reaction mass of methyl 2-methylbenzene-1-sulfonate and methyl toluene-4-sulphonate

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

A bacterial reverse mutation assay (Ames) according to OECD TG 471 was conducted for the evaluation of point mutagenic effects. In this assay 4 histidine auxotrophic mutants of Salmonella typhimurium (TA 1535, TA 1537, TA 100, TA 98) were used. The test material was, therefore, tested up to the maximum recommended dose level of 5000 µg/plate. Cytotoxicity in all of the Salmonella tester strains was observed at concentrations >= 2500 µg/plate.

The vehicle (DMSO) control plates gave counts of revertant colonies within the normal range. All of the positive control chemicals used in the test induced marked increases in the frequency of revertant colonies, both with or without metabolic activation.

According to the results in TA 100 and TA 1535 the substance is mutagenic in the Ames test under the experimental conditions chosen.

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

only four strains tested (E. coli WP2 strain or S. typhimurium TA 102 were not investigated)

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature
- Solubility and stability of the test substance in the solvent/vehicle: Complete solubility of the test substance in DMSO

Target gene:

histidine locus

Species / strain / cell type:

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

Metabolic activation:

with and without

Metabolic activation system:

S9-Mix from the liver of Aroclor 1254 induced male rats

Test concentrations with justification for top dose:

0, 20, 100, 500, 2500, 5000 µg/plate (with and without S9-mix)

Vehicle / solvent:

DMSO.

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitro-1,2-phenylene diamine, 2-aminoanthracene, N-methyl-N´-nitro-N-nitrosos-guanidine (MNNG), 9-aminoacridine chloride monohydrate

Remarks:

2-aminoanthracene (promutangen) only used with S9-mix, the other positive controls only used without S9-mix.

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DETERMINATION OF CYTOTOXICITY
- gross appraisal of background growth
- a toxic effect was assumed when there was a marked and dose-dependent reduction in the mutant-count per plate, compared to the negative controls
- total bacterial counts

Evaluation criteria:

In general, a substance to be characterized as positive in the Ames test has to fulfil the following requirements:
- doubling of the spontaneous mutation rate (control)
- dose-response relationship
- reproducibility of the results

Statistics:

Not specified.

Species / strain:

S. typhimurium, other: TA 1537 and TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

ambiguous

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

ADDITIONAL INFORMATION ON CYTOTOXICITY:
A bacteriotoxic effect (reduced his- background growth, decrease in the number of his+ revertants) was observed at doses >= 2500 µg/plate.

Remarks on result:

other: Slightly enhanced colony numbers at 500 µg/plate without S-9 mix and at 2500 µg/plate with metabolic activation.

Conclusions:

positive

Executive summary:

A bacterial reverse mutation assay (Ames) according to OECD TG 471 was conducted for the evaluation of point mutagenic effects. In this assay 4 histidine auxotrophic mutants of Salmonella typhimurium (TA 1535, TA 1537, TA 100, TA 98) were used. The test material was, therefore, tested up to the maximum recommended dose level of 5000 µg/plate. Cytotoxicity in all of the Salmonella tester strains was observed at concentrations >= 2500 µg/plate.

The vehicle (DMSO) control plates gave counts of revertant colonies within the normal range. All of the positive control chemicals used in the test induced marked increases in the frequency of revertant colonies, both with or without metabolic activation.

According to the results in TA 100 and TA 1535 the substance is mutagenic in the Ames test under the experimental conditions chosen.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (positive)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

A classification according to Regulation (EC) No 1272/2008, Annex I, is not warranted.