3,4-dichloro-α,α,α-trifluorotoluene

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

3,4-dichloro-α,α,α-trifluorotoluene is not considered to be mutagenic in a bacterial reverse mutation study.

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP, non-guideline study, available as unpublished report, limitations in design and/or reporting (for some strains inappropiate positive control reference substances were used), but otherwise adequate for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The substance was tested in a reverse mutation assay (Ames test) using five strains of Salmonella typhimurium (TA 1535, TA 1537, TA 1538, TA 98, TA 100) and one strain of Escherichia coli (WP2 uvrA pKM 101) in the presence and absence of metabolic activation.

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Target gene:

- S.typhimurium: His-locus
- E.coli: Trp-locus

Species / strain / cell type:

S. typhimurium, other: TA 1535, TA 1537, TA 1538, TA 98, TA 100

Additional strain / cell type characteristics:

not applicable

Species / strain / cell type:

E. coli WP2 uvr A pKM 101

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

Aroclor induced rat liver S9 mix

Test concentrations with justification for top dose:

31.25, 62.5, 125, 250, 500, 1000, 2000, 4000 µg/plate

Vehicle / solvent:

DMSO

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Remarks:

20 µg/plate

Positive control substance:

benzo(a)pyrene

Remarks:

TA 1538, TA 98, TA 100 (with and without metabolic activation)

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Remarks:

20 µg/plate

Positive control substance:

other: neutral red

Remarks:

TA 1537 (with and without metabolic activation)

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Remarks:

5 µg/plate

Positive control substance:

sodium azide

Remarks:

TA 1535 (with and without metabolic activation)

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Remarks:

20 µg/plate

Positive control substance:

other: potassium dichromate

Remarks:

E.coli (with and without metabolic activation)

Details on test system and experimental conditions:

- METHOD OF APPLICATION: in medium; in agar (plate incorporation)
- DURATION: Exposure duration: 48-72 h
- NUMBER OF REPLICATIONS: 3
- DETERMINATION OF CYTOTOXICITY: Reduction in background

Evaluation criteria:

Reproducable values of 2.5 x control value or greater are considered to indicate a mutagenic response

Species / strain:

S. typhimurium, other: TA 1537, TA1538, TA 98, TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

only without metabolic activation

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

other: For TA 1538, TA 98, TA 100, and TA 1537 only a valid positive control for assays with metabolic activation was tested.

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

other: For TA 1535 only a valid positive control for assays without metabolic activation was tested.

Species / strain:

E. coli WP2 uvr A pKM 101

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

only without metabolic activation

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

other: Only valid without metabolic activation.

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: The addition of 4000 µg/plate caused the pH of the medium to change from 7.31 to 7.32.
- Water solubility: The test compound formed small, oily pools in the top agar at amount of 1000 µg/plate and above, showing that is was not totally miscible in the aqueous test system.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
Microscopal evaluation of the background showed evidence of cytotoxicity in all of the bacterial tester strains, except TA 1535, in the absence of rat liver S9 fraction only. In the E.coli this was observed at 250 µg/plate onward, and in the S.typhimurium strains it was observed at 500 µg/plate onward.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results (migrated information):
negative

It is concluded that there is no evidence of induction of gene mutations by the test substance and its metabolites in the five S.typhimurium and one E.coli strains used in this study.

Executive summary:

The substance was tested for its mutagenic potential based on the ability to induce point mutations in several strains of Salmonella typhimurium (TA 1535, TA 1537, TA 1538, TA 98, TA 100) and one E.coli strain (WP2 uvrA pKM 101), with and without metabolic activation. Strains were exposed in a standard plate-incorporation test to 0, 31.25, 62.5, 125, 250, 500, 1000, 2000, and 4000 µg/plate. The test compound formed small, oily pools in the top agar at amount of 1000 µg/plate and above, showing that is was not totally miscible in the aqueous test system. The addition of 4000 µg/plate caused a small change in the pH of the medium. Microscopal evaluation of the background showed evidence of cytotoxicity in all of the bacterial tester strains, except TA 1535, in the absence of rat liver S9 fraction only. In the E.coli this was observed ate 250 µg/plate onward, and in the S.typhimurium strains it was observed at 500 µg/plate onward. An increase in the number of his+ or trp+ revertants was not observed with or without a metabolizing system. It was therefore concluded that the test substance is not mutagenic under these experimental conditions.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Additional information from genetic toxicity in vitro:

3,4-dichloro-α,α,α-trifluorotoluene was tested for its mutagenic potential based on the ability to induce point mutations in several strains of Salmonella typhimurium (TA 1535, TA 1537, TA 1538, TA 98, TA 100) and one E.coli strain (WP2 uvrA pKM 101), with and without metabolic activation (BASF SE 1987). Strains were exposed in a standard plate test to 0, 31.25, 62.5, 125, 250, 500, 1000, 2000, and 4000 µg/plate. The test compound formed small, oily pools in the top agar at amount of 1000 µg/plate and above, showing that is was not totally miscible in the aqueous test system. The addition of 4000 µg/plate caused a small change in the pH of the medium. Microscopal evaluation of the background showed evidence of cytotoxicity in all of the bacterial tester strains, except TA 1535, in the absence of rat liver S9 fraction only. In the E.coli this was observed at 250 µg/plate onward, and in the S.typhimurium strains it was observed at 500 µg/plate onward. An increase in the number of his+ or trp+ revertants was not observed with or without a metabolizing system. It was therefore concluded that the 3,4-dichloro-α,α,α-trifluorotoluene is not mutagenic under these experimental conditions.

In a bacterial reverse mutation assay presented in the ECHA disseminated dossier it was also concluded that 3,4-dichloro-α,α,α-trifluorotoluene was not mutagenic.

 

Additional information is available in a report (BG Chemie Toxikologische bewertungen, Nr. 89, 1997), in which a summary of study results is presented, for a structural analogue of 3,4-dichloro-α,α,α-trifluorotoluene. It is stated that 3-chloro-α,α,α-trifluorotoluene is not genetic toxic in vitro, because it does not cause gene mutations, chromosome aberrations, or has an effect on the DNA. This was tested in the Ames test, chromosome aberration test with V79 cells, DNA repair test with Bacillus subtilis, a test to determine mitotic gene conversion, and a mitotic cross-over test with Saccharomyces cerevisiae.

Justification for selection of genetic toxicity endpoint
Only one genetic toxicity in vitro study available.

Justification for classification or non-classification

Based on the negative results available for 3,4-dichloro-α,α,α-trifluorotoluene and its structural analogue 3-chloro-α,α,α-trifluorotoluene, classification for genetic toxicity is not warranted in accordance with EU Classification, Labeling and Packaging of Substance and Mixtures (CLP) Regulation No. 1272/2008 and EU Directive 67/548 (DSD).