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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
27 Jun. - 10 Jul. 2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report Date:
2007

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Principles of method if other than guideline:
plate incorporation assay and preincubation test
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Test material form:
liquid: viscous
Details on test material:
- Manufacturers identification: Novares TL 10, Novares L 100, Novares L 800, Novares C 10 (different types/technical products of the substance)
- Substance type: organic
- Test material is 'Naphtha (petroleum), steam-cracked, C8-10 aromatic hydrocarbon fraction, alkylated and oligomerised', EC list number 701-299-7 (assigned by ECHA after request for change of EC number/EC name). Originally, the substance Hydrocarbons, C9-unsaturated, polymerised, CAS No. 71302- 83-5, was submitted for registration. Subsequent to substance validation, the identity of the substance was changed by ECHA (EC number 615-276-2 and new name 'Distillates (petroleum), steam-cracked, C8-12 fraction", mainly C8 - C10 unsaturated aromatic and alkylaromatic hydrocarbons, predominantly styrene- and indene-derivatives, obtained by Lewis acid-initiated alkylation and polymerisation').
- for additional information see respective study records
Specific details on test material used for the study:
- Name of test material (as cited in study report): Novares L 100; CAS-no. 71302-83-5 (Hydrocarbons, C9- unsaturated, polymerized)
- Composition of test material, percentage of components: see Section 1.2 Composition
- Lot/batch No.: 24106
- Stability under test conditions: no measured data; based on chemical structure assumed to be stable
- Storage condition of test material: room temperature, exclusion of light

Method

Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102
Metabolic activation:
with and without
Metabolic activation system:
microsomal fraction prepared from rat livers (male Wistar rats) induced with phenobarbital (80 mg/kg bw) and ß-naphthoflavone (100 mg/kg bw) orally (3x)
Test concentrations with justification for top dose:
1st and 2nd experiment: 31.6, 100, 316, 1000, 2500, and 5000 µg/plate (all strains, +/-S9)
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: compatible with survival of bacteria and S9 activity
Controls
Untreated negative controls:
yes
Remarks:
dist. water
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
sodium azide
methylmethanesulfonate
other: 4-nitro-p-phenylenediamine: TA 98, TA 1537 without S9; 2-aminoanthracene: all strains with S9
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (1st experiment: plate incorporation); 2nd experiment: preincubation test

NUMBER OF REPLICATIONS: 3 per concentration

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth/colony formation


Evaluation criteria:
Considered as mutagenic
- if a clear and dose-related increase in the number of revertants occurs in at least one tester with or without metabolic activation and/or
- if a biologically relevant positive response for at least one of the dose groups occurs in at least one tester with or without metabolic activation.

An increase is considered relevant
- if in TA 100 and TA 102 mutation rate is at least twice as high as the rate of the solvent control;
- if in TA 98, TA 1535, and TA 1537 the mutation rate is at least 3x higher than that of the solvent control.
Statistics:
According to the OECD guidelines, the biological relevance is the criterion for the interpretation of the results: a statistical evaluation was not considered necessary under this premise (report p. 20).

Results and discussion

Test resultsopen allclose all
Key result
Species / strain:
S. typhimurium TA 1535
Metabolic activation:
with and without
Genotoxicity:
negative
Remarks:
reproducible in both tests
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Remarks:
reproducible in both tests
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Remarks:
reproducible in both tests
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Remarks:
reproducible in both tests
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 102
Metabolic activation:
with and without
Genotoxicity:
negative
Remarks:
reproducible in both tests
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid

Applicant's summary and conclusion

Conclusions:
No biologically relevant increases in revertant colony numbers of any of the five tester strains were observed following treatment with the test substance 'Naphtha (petroleum), steam-cracked, C8-10 aromatic hydrocarbon fraction, alkylated and oligomerised' (Novares L 100) at any concentration level, neither in the presence nor in the absence of metabolic activation. All reference mutagens induced distinct increases of revertant colonies indicating the validity of the experiment. The test substance was shown to be not mutagenic in this bacterial reverse mutation assay.