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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 from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
No data reported
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study is classified as reliable without restriction because it was carried out in a method similar to OECD TG 471 with modifications.

Data source

Reference
Reference Type:
publication
Title:
Estimation of the dermal carcinogenic activity of petroleum fractions using a modified Ames assay
Author:
Blackburn GR, Deitch RA, Schreiner CA, Mehlman MA, and Mackerer CR
Year:
1984
Bibliographic source:
Cell Biol Toxicol, Vol 1(1), pp 67-80

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
with modifications
Principles of method if other than guideline:
Method: other: procedure described in paper by Blackburn et al. The light paraffinic distillate was extracted with dimethylsulphoxide by performing five successive one-to-one extractions and pooling extracts. The pooled extract sample was stored at 4 degrees celsius in an amber bottle until assayed.
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
other: Oily liquid
Details on test material:
Test substance:
Sample number 3 CAS 64741-50-0

Method

Target gene:
Not applicable
Species / strain
Species / strain / cell type:
other: Modified Ames Test using Salmonella typhimurium strain TA 98 and Aroclor 1254-induced rat or hamster liver S-9
Details on mammalian cell type (if applicable):
Not applicable
Additional strain / cell type characteristics:
not specified
Metabolic activation:
with
Metabolic activation system:
Aroclor 1254-induced rat or hamster liver S9
Test concentrations with justification for top dose:
range of doses that provided an initial linear dose response; specific doses not stated.
Vehicle / solvent:
No data reported.
Controls
Untreated negative controls:
not specified
Negative solvent / vehicle controls:
not specified
True negative controls:
not specified
Positive controls:
yes
Remarks:
benzo(a)pyrene at 5 ug/plate and 2-aminoanthracene at 2 ug/plate
Positive control substance:
not specified
Details on test system and experimental conditions:
The light paraffinic distillate was extracted with dimethylsulphoxide by performing five successive one-to-one extractions and pooling extracts. The pooled extract sample was stored at 4 degrees celsius in an amber bottle until assayed.
Evaluation criteria:
A tangent to the dose-response curve at zero dose was constructed to provide the Mutagenicity Index.
Statistics:
A tangent to the dose-response curve at zero dose was constructed to provide the Mutagenicity Index.

Results and discussion

Test results
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
not specified
Untreated negative controls validity:
not specified
Positive controls validity:
valid
Remarks on result:
other: other: Modified Ames Test using Salmonella typhimurium strain TA 98 and Aroclor 1254-induced hamster liver S-9
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

The test substance was not mutagenic in standard assay, but extraction with DMSO produced a mutagenic response.  The mutagenicity index was 17.  This compares with values of 0 for a solvent refined oil and 40 for a cracked distillate.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
positive with metabolic activation

DMSO-extracted light paraffinic distillate was classified as mutagenic and produced a mutagenicity index of 17. Assay sensitivity (the number of TA98 revertants per plate) improved with 8-fold increase of S9.
Executive summary:
In a modified in vitro mutagenicity assay, S. typhimurium strain TA98 was exposed to a DMSO-extracted light paraffinic distillate at a concentration of 50 microlitres per plate with metabolic activation (Aroclor 1254 -induced rat or hamster liver S9) using the standard pre-incubation method. The test substance was considered mutagenic and produced a mutagenicity index of 17. This study received a Klimisch score of 1 and is classified as reliable without restriction because it was carried out in a method similar to OECD TG 471 with modifications.