Registration Dossier

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
Study period:
2008
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Study conducted in compliance with agreed protocols, with no deviations from standard test guidelines and no methodological deficiences, which do not affect the quality of the relevant results. The study report was conclusive, done to a valid guideline and the study was conducted under GLP conditions.

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
2008

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
EPA OPPTS 870.5265 (The Salmonella typhimurium Bacterial Reverse Mutation Test)
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
Allyl bromide was obtained from Fluka Chemical Corporation (Buchs, Switzerland) in one lot (330638) and from Aldrich Chemical Co. in one lot (03614HN). Lot 330638 was used in the 2-week studies, and lot 03614HN was used in the 40-week studies. Identity and purity analyses were conducted by the analytical chemistry laboratory, Midwest Research Institute (Kansas City, MO) and the study laboratory, BioReliance (Rockville, MD). Reports on analyses performed in support of the allyl bromide studies are on file at the National Institute of Environmental Health Sciences.
Both lots of allyl bromide, a clear, colorless liquid, were identified by the analytical chemistry laboratory using infrared and proton nuclear magnetic resonance (NMR) spectroscopy and by the study laboratory using infrared spectroscopy. All infrared and NMR spectra were consistent with the literature spectra and spectra of a reference standard from the same lot. The purity of each lot was determined by the analytical chemistry and study laboratories using gas chromatography (GC). For lot 330638, GC indicated one major peak and five impurities with a combined peak area of 0.7% relative to the total peak area. GC by a second system indicated one major peak and three impurities with a combined peak area of less than 0.5%. The relative purity was 102% when compared to a reference standard from the same lot. The overall purity of lot 330638 was greater than 99%. For lot 03614HN, GC indicated one major peak and four impurities with a combined peak area of 0.45% relative to the total peak area. GC by a second system indicated one major peak and three impurities with a total combined area less than 0.3% of the total peak area. The relative purity was 102% when compared to a frozen reference from the same lot. The overall purity of lot 03614HN was greater than 99%. During the 40-week studies, additional purity analyses were performed by the study laboratory at 26 weeks and at the end of the study using GC.
To ensure stability, the bulk chemical was stored in a sealed container under a nitrogen headspace, protected from light, at 2° to 8° C. No degradation of the bulk chemical was detected.

Method

Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Metabolic activation system:
metabolic activation enzymes and cofactors from Aroclor 1254-induced male Sprague-Dawley rat or Syrian hamster liver
Test concentrations with justification for top dose:
Dose : 0, 3, 10, 33, 100, 333, 666 and 1000 µg/plate
Details on test system and experimental conditions:
Testing was performed as reported by Zeiger et al. (1992). Allyl bromide was sent to the laboratory as a coded aliquot from Radian Corporation (Austin, TX). It was incubated with the Salmonella typhimurium tester strains TA98 and TA100 either in buffer or S9 mix (metabolic activation enzymes and cofactors from Aroclor 1254-induced male Sprague-Dawley rat or Syrian hamster liver) for 20 minutes at 37º C. Top agar supplemented with l-histidine and d-biotin was added, and the contents of the tubes were mixed and poured onto the surfaces of minimal glucose agar plates. Histidine-independent mutant colonies arising on these plates were counted following incubation for 2 days at 37° C.
Each trial consisted of triplicate plates of concurrent positive and negative controls and five doses of allyl bromide. The high dose was limited by toxicity. All trials that gave a positive response were repeated.
Evaluation criteria:
In this assay, a positive response is defined as a reproducible, dose-related increase in histidine-independent (revertant) colonies in any one strain/activation combination. An equivocal response is defined as an increase in revertants that is not dose related, is not reproducible, or is not of sufficient magnitude to support a determination of mutagenicity. A negative response is obtained when no increase in revertant colonies is observed following chemical treatment. There is no minimum percentage or fold increase required for a chemical to be judged positive or weakly positive.

Results and discussion

Test results
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
valid
Positive controls validity:
valid
Additional information on results:
Allyl bromide was mutagenic in Salmonella typhimurium strain TA100, with and without Aroclor-induced rat or hamster liver S9 (Table E1). The concentration ranges tested were 10 to 1,000 μg/plate without S9 and 3 to 333 μg/plate with S9; significant increases in revertants occurred at concentrations of 100 μg/plate and above. The mutagenic response obtained in the absence of S9 was stronger than that observed with either rat or hamster liver S9. No mutagenicity was detected in the S. typhimurium strain TA98, with or without S9, over the same concentration ranges.
Remarks on result:
other: strain/cell type: TA 98 and TA 100
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
positive
Executive summary:

Allyl bromide was mutagenic in S. typhimurium strain TA100, with and without exogenous metabolic activation (S9). No mutagenicity was detected in S. typhimurium strain TA98, with or without S9, over the same concentration range tested with TA100.