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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:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Near-guideline, GLP-compliant study. Adequate for assessment.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1986
Report date:
1986

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Principles of method if other than guideline:
Salmonella typhimurium TA98 exposed using either a standard plate incorporation assay or a modified protocol (8-fold increase in S9; 3-fold increase in NADP)
GLP compliance:
yes
Type of assay:
bacterial gene mutation assay

Test material

Constituent 1
Reference substance name:
64741-62-4
Cas Number:
64741-62-4
IUPAC Name:
64741-62-4
Test material form:
other: Viscous hydrocarbon liquid
Details on test material:
Catalytic cracked clarified oil (CCCO), CAS No. 64741-62-4.
Sample No API 81-15
Gravity degrees API: 0.1
Specific gravity: 1.0753
Viscosity in SUS 210 °F: 56.1
Flash Pt °F: 396
Ash, weight %: 0.05
Sulfur weight %:1.1
Pour Pt °F: 35
Asphaltenes (MM-596): 4.2 %
Carbon residue in weight %: 4.6

Method

Target gene:
hisD3052
Species / strain
Species / strain / cell type:
S. typhimurium TA 98
Details on mammalian cell type (if applicable):
not applicable
Additional strain / cell type characteristics:
not applicable
Metabolic activation:
with
Metabolic activation system:
Aroclor 1254-induced rat S9
Test concentrations with justification for top dose:
Trial 1: 1000, 5000, 10000, 25000, 50000 ug/plate
Trial 2: 33, 100, 333, 1000, 3333 ug/plate
Vehicle / solvent:
DMSO
Controls
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene (4 ug); perylene (50 ug)
Details on test system and experimental conditions:
Standard plate incorporation assay: 10% Aroclor 1254- induced rat S9 homogenate mix per ml; 4 mM NADP
Modified protocol: 80% S9 homogenate per ml; 12 mM NADP
Testing performed twice (independent repeat)
2-aminoanthracene and perylene used as positive control substances
Evaluation criteria:
Doubling in mutation frequency
Statistics:
None reported

Results and discussion

Test results
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
>10000 ug/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Remarks on result:
other: strain/cell type: Modified Ames assay using Salmonella typhimurium strain TA98
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

In both cases, significant and reproducible dose-dependent increases in the number of revertants were obtained.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
positive

positive in Salmonella typhimurium TA98 in vitro with and without metabolic activation
Executive summary:

The mutagenic potential of catalytic cracked clarified oil (up to 50000 µg/plate; sample API 81-15) was investigated in a non-guideline GLP-compliant study. Four separate tests were conducted in duplicate using S. typhimurium strain TA 98 in the presence of either 10% Aroclor 1254-induced rat liver S9 mix and 4 mM NADP or 80% S9 mix and 12 mM NADP; 2-aminoanthracene and perylene were used as positive control substances. A two-fold increase in revertants per plate was regarded as a positive response.

The test substance was positive in all 4 tests, with the number of revertants increased maximally 13.1, 27.8, 44 and 46.3-fold, respectively over solvent controls. The largest increase in revertants occurred in the assays activated with 80% S-9 and 12 mM NADP. A satisfactory response was obtained with the positive control substances.

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