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Toxicological information

Genetic toxicity: in vivo

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Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / bone marrow chromosome aberration
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: This study is classified as reliable with restrictions because, though it does not follow a prescribed guideline, it is well conducted and reported.

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1994

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Principles of method if other than guideline:
No specific GLP guideline was followed. The study is well conducted and reported.
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
other: low viscosity liquid hydrocarbon
Details on test material:
- Name of test material (as cited in study report): Home heating oil
- Substance type: Mixtures of hydrocarbons
- Boiling range °F: 248-800
- Aromatic content: 44.8 wt % (4+ ring aromatics 0.351 wt %)

Test animals

Species:
mouse
Strain:
CD-1
Sex:
male/female

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
corn oil
Doses / concentrations
Remarks:
Doses / Concentrations:
1.0, 2,5, 5,0 g/kg
Basis:
no data
No. of animals per sex per dose:
15 male 15 female / dose level

Examinations

Tissues and cell types examined:
bone marrow erythrocytes
Details of tissue and slide preparation:
bone marrow smears harvested at 24, 48, 72 hrs post exposure

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
valid
Negative controls validity:
not examined
Positive controls validity:
valid

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
The study authors concluded that home heating oil did not exhibit a positive response when tested for micronucleus induction.
Executive summary:

In a micronucleus assay, fifteen male and female CD-1 mice were treated with 1.0, 2.5, or 5.0 g/kg of home heating oil dissolved in corn oil via oral gavage. A concurrent control group received only corn oil, while another group served as positive control and was treated with 0.04 g/kg cyclophosphamide.

Five male and female mice from each dose group were sacrificed 24, 48 or 72 hours after test material administration. Bone marrows were removed and examined for the presence of micronuclei. Mice treated with cyclophosphamide were sacrificed 24 hours after administration. The micronucleus assay was conducted using the Schmid method. Erythrocytes numbering 1,000, were counted for each animal bone marrow slide and the number of polychromatic (PCE) and normochromatic (NCE) erythrocytes were tabulated. Frequency of micronucleus induction was determined by examining the number of micronuclei per 1,000 PCEs. 

There was no increase in the frequency of micronuclei for the test material. In addition, there was no evidence of bone marrow depression. Cyclophosphamide, the positive control, exhibited appropriate results and the vehicle control result was within the normal range. Based on these results the study authors concluded home heating oil did not exhibit a positive response. 

This study received a Klimisch rating of “reliable with restrictions” because, though it does not follow a prescribed guideline, it is well conducted and reported.