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Toxicological information

Genetic toxicity: in vitro

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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:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Acceptable, well documented publication which meets basic scientific principles

Data source

Reference
Reference Type:
publication
Title:
A study on the mutagenic activity of styrene and styrene oxide
Author:
Vainio H et al
Year:
1976
Bibliographic source:
Scand. j. work environ. & health 3 (1976) 147-151
Report Date:
1976

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
no positive controls
GLP compliance:
no
Remarks:
study performed before implementation of GLP
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Species / strain
Species / strain / cell type:
S. typhimurium, other: TA1535, TA1537, TA1538, TA100 and TA98
Metabolic activation:
with and without
Metabolic activation system:
S9
Test concentrations with justification for top dose:
10 exp.-4 , 10 exp. -5, 10 exp. -6, 10 exp. -7 , 10 exp. –8 , 10 exp. –9, 0 mol / plate
Vehicle / solvent:
ethanol
Controls
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
no

Results and discussion

Test results
Species / strain:
S. typhimurium, other: TA1535, TA1537, TA1538, TA100 and TA98
Metabolic activation:
with and without
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not specified
Positive controls validity:
not specified
Additional information on results:
strains TA 1537 and TA 98 were tested negative
Remarks on result:
other: strain/cell type: TA 1535, TA 1538, TA 100
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
positive

The test compound was positive in three of five strains and is therfore regarded positive in the bacterial reverse mutation assay
Executive summary:

In a reverse gene mutation assay in bacteria, strains TA1535, TA1537, TA1538, TA100 and TA98 ofS. typhimuriumwere exposed to Styrene Oxide dissolved in ethanol at concentrations of 10 exp-4, 10 exp. -5, 10 exp. -6, 10 exp. -7 , 10 exp. –8 , 10 exp. –9, 0 mol / plate in the presence and absence of mammalian metabolic activation (liver S9 mix from rats induced with Clophen) using the co-incubation method. 

Styrene Oxide was tested up to cytotoxic concentrations (10 exp-4 mol/plate). In strain TA 1535, a dose related increase to 357 (without metabolic activation) and 484 (with metabolic activation) revertants vs. 20 and 45 revertants in control was observed. In strain TA 100, a dose related increase to 1111 (without metabolic activation) and 1165 (with metabolic activation) revertants vs. 84 and 135 revertants in control was observed.  There was a concentration related positive response of induced mutant colonies over background.

This study is classified as acceptable. This study satisfies the requirement for Test Guideline  OPPTS 870.51001; OECD 471 for in vitro mutagenicity (bacterial reverse gene mutation) data. The lack of a positive control is acceptable as the test compound is clearly positive and thus demonstrates adequate sensitivity of the test system.