Trifluoro(trifluoromethyl)oxirane

Genetic toxicity: in vitro

Administrative data

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:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This study was selected as the key study because the information provided for the hazard endpoint is sufficient for the purpose of classification and labeling and/or risk assessment.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

Remarks:

Conducted according to guideline in effect at time of study conduct

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.5100 - Bacterial Reverse Mutation Test (August 1998)

Deviations:

no

Remarks:

The study was conducted according to the guideline in effect at the time of study conduct.

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Trifluoro(trifluoromethyl)oxirane

EC Number:

207-050-4

EC Name:

Trifluoro(trifluoromethyl)oxirane

Cas Number:

428-59-1

Molecular formula:

C3F6O

IUPAC Name:

2,2,3-trifluoro-3-(trifluoromethyl)oxirane

Details on test material:

- Purity: 99.544%

Method

Target gene:

histidine

Species / strain

Species / strain 1

Species / strain / cell type:

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

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

Aroclor-induced rat liver S9

Test concentrations with justification for top dose:

preliminary toxicity test: 2800, 6900, 8300, 9700, 14000, 32000 and 37000 µmole per liter
second preliminary toxicity test: 240, 360, 550, 820, 1200, 1800 and 2800 µmole per liter
initial mutagenicity test: 48, 110, 240, 550, 1200 and 2800 µmole per liter
ftrst repeat mutagenicity assay: 9.4, 21, 48, 110, 240 and 550 µmole per liter
second repeat mutagenicity assay: 9.4, 21, 48, 110,240,550 and 1200 µmole per liter

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: air

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene (all strains +S9), 2-nitrofluorene (TA98 -S9), sodium azide (TA100 and TA1535 -S9), 9-aminoacridine (TA1537 -S9), methyl methane sulfonate (WP2urvA -S9)

Details on test system and experimental conditions:

METHOD OF APPLICATION: One-half (0.5) milliliter of S9 or Sham mix and 100 µL of tester strain were added to 2.0 mL of molten selective top agar at 45±2°C. After vortexing, the mixture was overlaid onto the surface of 25 mL of minimal bottom agar. The overlaid plates were inverted and placed
uncovered in the appropriate number of 9-liter desiccators. An appropriate quantity of the test substance was introduced into each desiccator by withdrawing an appropriate amount of air and replacing it with the test substance.

DURATION
- Exposure duration: The desiccators were incubated, with stirring, for approximately 24 hours at 37±2°C.
- Expression time (cells in growth medium): Following the 24-hour incubation, the plates were removed from the desiccators and incubated with the lids replaced at 37±2°C for an additional 24 to 48 hours.
- Fixation time (start of exposure up to fixation or harvest of cells): 48 to 72 hours

NUMBER OF REPLICATIONS: 3

Evaluation criteria:

For the test substance to be evaluated positive, it must have caused a dose-related increase in the mean revertants per plate of at least one tester strain over a minimum of two increasing concentrations of test substance. Data sets for tester strains TA1535 and TA1537 were judged positive if the increase in mean revertants at the peak of the dose response is equal to or greater than 3.0-times the mean vehicle control value. Data sets for tester strains TA98, TAl00 and
WP2 uvrA were judged positive if the increase in mean revertants at the peak of the dose response was equal to or greater than 2.0-times the mean vehicle control value.

The following criteria must be met for the mutagenicity test to be considered valid. All Salmonella tester strain cultures must demonstrate the presence of the deep rough mutation (rfa) and the deletion in the uvrB gene. Cultures of tester strains TA98 and TAl00 must demonstrate the presence of the pKM101 plasmid R-factor. All WP2 uvrA cultures must demonstrate the deletion in the uvrA gene. All cultures must demonstrate the characteristic mean number of spontaneous revertants in the vehicle controls as follows (inclusive): TA98 , 10 - 50; TAl00, 80 - 240; TA1535, 5 - 45; TA1537, 3 - 21; WP2 uvrA, 10 - 60. To ensure that appropriate numbers of bacteria are plated, tester strain culture titers must be greater than or equal to 0.3x10e9 cells/mL. The mean of each positive control must exhibit at least a 3.0-fold increase in the number of revertants over the mean value of the respective vehicle control. A minimum of three non-toxic dose levels is required to evaluate test data. A dose level is considered toxic if one or both of the following criteria are met: (1) A >50 % reduction in the mean number of revertants per plate as compared to the mean vehicle control value. This reduction must be accompanied by an abrupt dose-dependent drop in the revertant count. (2) A moderate reduction in the background lawn.

Statistics:

For each replicate plating, the mean and standard deviation of the number of revertants per plate were calculated.

Results and discussion

Test results

Test results 1

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

Initial mutagenicity test toxicity beginning at 240 or 550 µmole/L . First repeat mutagenicity assay, toxicity beginning at 240 or 550 µmole/L. Second repeat mutagenicity assay, toxicity beginning at 550 µmole/L

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

Initial mutagenicity test toxicity beginning 2800 µmole/L

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

In the initial preliminary toxicity test, the maximum dose tested was 37000 µmole per liter. This dose represents a 90% replacement of ambient air with test substance. Dose levels tested were 2800, 6900, 8300, 9700, 14000, 32000 and 37000 µmole per liter. No precipitate was observed but toxicity was observed beginning at 2800 µmole per liter. A second preliminary toxicity test was performed with dose levels 240, 360, 550, 820, 1200, 1800 and 2800 µmole per liter. No precipitate was observed but toxicity was observed beginning at 550, 820, 1200 or 1800 µmole per liter. Based on the findings of the toxicity test, the maximum dose plated in the mutagenicity test was 2800 µmole per liter.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

This study and the conclusions which are drawn from it fulfill the quality criteria (validity, reliability, repeatability).
The results of the Bacterial Reverse Mutation Test Using Gas-Phase Exposure indicate that, under the conditions of this study, the test substance did not cause a positive mutagenic response in either the presence or absence of Aroclor-induced rat liver S9.

Executive summary:

The test substance was tested in the Bacterial Reverse Mutation Test using gas-phase exposure using Salmonella typhimurium tester strains TA90, TA100, TA1535, TA1537, and Escherichia coli tester strain WPuvrA in the presence and absence of Aroclor-induced rat liver S9. The test was performed in two phases, using the desiccator method. The first phase, the preliminary toxicity test, was used to establish the dose-range for the mutagenicity test. The second phase, the mutagenicity test, was used to evaluate the mutagenic potential of the test substance. Untreated controls (air controls) were used as the negative controls.

In the initial preliminary toxicity test, the maximum dose tested was 37000µmole per liter. This dose represents a 90% replacement of ambient air with test substance. Dose levels tested were 2800, 6900, 8300, 9700, 14000, 32000, and 37000µmole per liter. No precipitate was observed but toxicity was observed beginning at 2800µmole per liter. A second preliminary toxicity test was performed under the same test conditions with dose levels of 240, 360, 550, 820, 1200, 1800, and 2800µmole per liter. No precipitate was observed but toxicity was observed beginning at 550, 820, 1200, or 1800µmole per liter. Based on the findings of the toxicity test, the maximum dose plated in the mutagenicity test was 2800µmole per plate. 

In the initial mutagenicity test, no positive mutagenic response was observed with tester strain WP2uvrA in the presence of S9 activation and with tester strains TA98, TA1535, and WP2uvrA in the absence of S9 activation. The dose levels tested were 48, 110, 240, 550, 1200, and 2800µmole. No precipitate was observed. Toxicity was observed beginning at 240 or 550µmole per liter with Salmonella tester strains and at 2800µmole per liter with E. coli. In the first repeat mutagenicity assay with tester strains TA98, TA100, TA1535, and TA1537 in the presence of S9 activation and tester strains TA100 and TA1537 in the absence of S9 activation, dose levels tested were 9.4, 21, 48, 110, 240, and 550µmole per plate. No positive mutagenic response was observed. No precipitate was observed.  Toxicity was observed beginning at 240 or 550µmole per liter. In the second repeat mutagenicity assay with tester strain TA100 in the absence of S9 activation, dose levels tested were 9.4, 21, 48, 110, 240, 550, and 1200µmole per plate. No positive mutagenic response was observed. No precipitate was observed but toxicity was observed beginning at 550µmole per liter.

The results of the Bacterial Reverse Mutation Test Using Gas-Phase Exposure indicate that, under the conditions of the study, the test substance did not cause a positive mutagenic response either in the presence or absence of Aroclor-induced rat liver S9.