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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:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP compliant, guideline study, available as unpublished report, no restrictions, fully adequate for assessment.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report Date:
2004

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Dicyclopentadiene/Codimer Concentrate
- Synonyms: DCPD/Codimer Concentrate, DCP97, H-25430
- CA Index name: Naphtha (petroleum), light steam-cracked, debenzenized, C8-16-cycloalkadiene concentrate
- Lot number: 121302
- Substance type: a distillate from a C8+ fraction of thermally processed pyrolysis gasoline obtained from ethylene production
- Physical state: colourless liquid
- Purity: Not applicable (The test substance was within specifications and the occurrence and distribution of isomers was as expected).
- Stability under test conditions: stable at room temperature below 70°F, protected from light and air
- Composition of test material, percentage of components:
29.175 wt % endo- and exo-DCPD
18.726 wt % C4-MCPD and C5-MCPD codimers
13.210 wt % MCPD dimer
12.903 wt % CPD-MCPD codimer
8.129 wt % C8 aliphatic and aromatic hydrocarbons
7.144 wt % C4-CPD and C5-CPD codimers
3.625 wt % MCPD-C7 dimer
2.771 wt % Tetrahydroindene
1.917 wt % Trimers
0.927 wt % C7 cyclic hydrocarbon
0.697 wt % C5 acyclic hydrocarbon dimer
0.634 wt % MCPD monomer
0.078 wt % CPD monomer
0.063 wt % C6 acyclic hydrocarbons


Method

Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
S9 from Aroclor induced rat liver
Test concentrations with justification for top dose:
15, 50, 150, 500, 1500 and 5000 µg per plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: ethanol
Controls
Negative solvent / vehicle controls:
yes
Remarks:
ethanol
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene, 2-nitrofluorene, sodium azide, 90aminoacridine, methyl methanesulfonate
Remarks:
+S9: All S.typh strains 1 µg/plate, E.coli 10 µg/plate. -S9: S. typh TA98 2-nitrofluorene 1 µg/plate, TA100 and TA1535 sodium azide 1 µg/plate, TA1537 9-aminoacridine 75 µg/plate, E.coli methyl methanesulfonate 1000 µg/plate
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48-72 hours

NUMBER OF REPLICATIONS: 3

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth
Evaluation criteria:
For each replicate plating, the mean and SD of the number of revertants/plate were counted. For a positive result, there must be a dose-related increase in the mean revertants/plate of at least one tester strain over a minimum of 2 increasing concentrations of test substance. Data sets for TA1535 and TA1537 were judged positive if the increase in mean revertants at the peak of the dose response ≥ 3 times the mean vehicle control value. Data sets for TA98, TA100 and WP2uvrA were positive if the increase in mean revertants at the peak of the dose response ≥ 2 times mean vehicle control value.

Results and discussion

Test resultsopen allclose all
Key result
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
some conditions beginning at 667, 1000 or at 5000 µg/plate
Vehicle controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
some conditions beginning at 667, 1000 or at 5000 µg/plate
Vehicle controls validity:
valid
Positive controls validity:
valid

Applicant's summary and conclusion

Conclusions:
Interpretation of results:
negative with metabolic activation
negative without metabolic activation

Dicyclopentadiene/codimer concentrate did not cause a positive response in either the presence or absence of Aroclor-induced rat liver S9.
Executive summary:

Dicyclopentadiene/codimer concentrate was tested in a bacterial reverse mutation test using Salmonella typhimurium tester strains TA98, TA100, TA1535 and TA1537 and Escherichia coli tester strain WP2 uvrA in the presence and absence or Aroclor-induced rat liver S9.

In the mutagenicity test, no positive mutagenic response was observed. The dose levels tested were 15, 15, 150, 500, 1500 and 5000 ug/plate. Toxicity was seen with some concentrations starting at 1500 or at 5000 ug/plate. No precipitate was observed.

It is concluded that dicyclopentadiene/codimer concentrate (CAS 68478-10-4) did not cause a positive response in either the presence or absence of Aroclor-induced rat liver S9 and is considered not to be mutagen in this test system.