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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study was classified as reliable without restriction because it is an acceptable and a well-documented study report.
Justification for type of information:
The standard OECD 471 test is not suitable to test petroleum UVCBs, because it has a tendency to produce false negatives for these substances. Therefore, the petroleum industry has developed a Modified Ames assay, optimized to accurately identify positive results for this endpoint. This deviation from the prescribed testing procedure requires some further explanation which is given in the attached document. The document gives a brief history of the development of the Modified Ames test and outlines Concawe’s proposed work (as part of a wider testing strategy, see Annex 13) to further support the use of this test for PS.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991

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:
The method used for this study was a modified Ames test (ASTM E1687). Because the standard Ames test is considered to be inappropriate for testing the mutagenicity of water insoluble petroleum products, the Ames test was modified as described in Blackburn and co-workers (1986). Substances tested were considered positive if they showed a mutagenicity index (MI) greater than 1.0. The hydrotreated kerosines and the straight-run, wet-treated
kerosine had MI values of 0.0.
GLP compliance:
not specified
Type of assay:
other: Modified Ames assay

Test material

Constituent 1
Reference substance name:
8008-20-6
Cas Number:
8008-20-6
IUPAC Name:
8008-20-6
Constituent 2
Reference substance name:
straight run kerosine
IUPAC Name:
straight run kerosine
Test material form:
other: low viscosity liquid hydrocarbon
Details on test material:
Test Substance: Kerosine, CAS No. 8008-20-6

One sample was tested.
Sample CAS No. Treatment Source Crude
1 8008-20-6 wet treated Middle East
- Name of test material (as cited in study report): DMSO Extracts of kerosine
- Storage condition of test material: indoors under nitrogen blanket.
- Other: Temperature of storage space maintained above 0 degrees Celsius

Kinematic viscosity (cSt): 1.24
- Flash point (°C): fire 52
- Distillation range 10 and 90 ml (°C): 168.8-236.1
- Sulphur content: 0.22%
- Nitrogen content (mg/l): 1.0
- Relative density: 0.7933
- Aniline point: 62.4
- Aromatics (%) 17.2
- Olefins (%) 1.3
- Saturates (%): 81.5

Test Substance CAS No 64742-81-0

Two samples were tested (Straight run hydrotreated) - one from Middle East and one from North Sea

- Kinematic viscosity (cSt): 1.26; 1.11
- Flash point (°C): fire 49;49
- Distillation range 10 and 90 ml (°C): 175-237; 163.4-227.7
- Sulphur content: 0.14%; 3.9 ppm
- Nitrogen content (mg/l): 1.3; 0.6
- Relative density: 0.7978 ; 0.8029
- Aniline point 61.4 ; 52.8
- Aromatics (%) 17.1 ; 22.3
- Olefins (%) 1.7; 1.8
- Saturates (%): 81.2 ; 75.9
- PAC 3-7 rings (% wt): 0; 0

Method

Species / strain
Species / strain / cell type:
other: S. typhimurium TA98
Metabolic activation:
not specified
Test concentrations with justification for top dose:
50 µl/mL
Controls
Untreated negative controls:
no
Positive controls:
no

Results and discussion

Test results
Species / strain:
S. typhimurium TA 98
Metabolic activation:
not specified
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Remarks on result:
other: strain/cell type: S. typhimurium TA98
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

The mutagenicity indices of the three samples were all zero, thus demonstrating an absence of mutagenic activity. Interestingly, none of the samples was found to contain any measurable 3-7 ring PACs.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

None of the kerosines tested were mutagenic.
Executive summary:

A standard Ames test were conducted on wet treated, straight-run kerosines and hydrotreated kerosines. S. typhimurium were exposed to kerosine and solvent DMSO at concentrations of 50 µL/mL. Because the standard Ames test is considered inappropriate for testing the mutagenicity of water insoluble petroleum products, the Ames test was modified according to Blackburn (1986) in order to be applied to straight-run kerosines. Substances tested were considered positive if they showed a mutagenicity index greater than 1.0. All three kerosines tested had MI values of 0.0, thus were not considered to be mutagenic.

This study received a Klimisch score of 1and is classified as reliable without restriction because it is an acceptable and a well-documented study report.