Distillates (coal tar), light oils

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

Study period:

02 - 28 Aug. 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Test guideline 2

Qualifier:

according to guideline

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. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Distillates (coal tar), light oils

EC Number:

283-483-2

EC Name:

Distillates (coal tar), light oils

Cas Number:

84650-03-3

Molecular formula:

N/A

IUPAC Name:

Distillates (coal tar), light oils

Details on test material:

- Name of test material (as cited in study report): Carbolic oil
- Molecular formula (if other than submission substance): not applicable
- Molecular weight (if other than submission substance): not applicable
- Substance type: organic
- Physical state: liquid
- 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 1

Species / strain / cell type:

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

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 102

Metabolic activation:

with and without

Metabolic activation system:

Microsomal fraction prepared from induced livers of 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 experiment: 10, 31.6, 100, 316, 1000, 2500, and 5000 µg/plate (all strains, +/-S9, except TA 98)
31.6, 100, 316, 1000, 2500, and 5000 µg/plate (TA 98, +/-S9)
2nd experiment: 3.16, 10, 31.6, 100, 316, 1000, and 2500 µg/plate (TA 100, TA 1537, +/- S9)
10, 31.6, 100, 316, 1000, 2500, and 5000 µg/plate (TA 98, +/- S9)
3.16, 10, 31.6, 100, 316, and 1000 µg/plate (TA 102, +/- S9)
1.0, 3.16, 10, 31.6, 100, 316, and 1000 µg/plate (TA 1535, +/- 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

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

other: see Report p. 15

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. 21).

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

Remarks:

reproducible in both tests

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

plate incorporation test: from >= 316 µg/pl. (-S9) to >= 1000 µg/pl. (+S9) / preincubation test: from >= 100 µg/pl. (-S9) to >= 316 µg/pl. (+S9)

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium, other: TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Remarks:

reproducible in both tests

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Remarks:

plate incorporation test: at >= 1000 µg/pl. (+/-S9) / preincubation test: at >= 100 µg/pl. (-S9); at >= 316 µg/pl. (+S9)

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Any other information on results incl. tables

Summary:

No biologically relevant increases in revertant colony numbers of any of the five tester strains were observed following treatment with Carbolic Oil 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.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative