Hydrocarbons, C7, n-alkanes, isoalkanes, cyclics

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian germ cell study: cytogenicity / chromosome aberration

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

July 1978 - January 1980

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline with acceptable restrictions.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Cross-reference

Reason / purpose for cross-reference:

read-across: supporting information

Reference

Endpoint:

in vivo mammalian germ cell study: cytogenicity / chromosome aberration

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

July 1978 - January 1980

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline with acceptable restrictions.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across source

Key result

Sex:

male/female

Genotoxicity:

negative

Remarks:

At dose level of 400 and 1200 ppm the test substance was not mutagenic in rats by the dominant-lethal test.

Toxicity:

no effects

Vehicle controls validity:

other: no vehicle was used

Negative controls validity:

valid

Positive controls validity:

valid

No treatment-related effects were observed for mortality, in-life physical or necropsy examinations and for body weights in males.

No treatment effect was indicated from microscopic evaluation of testes, seminal vesicles, epididymides and prostate tissues from 5 randomly chosen males from each exposure group.

In one animal of the 400 ppm exposure group a caseous mass was observed in the left epididymis. This caseous mass was seen microscopically to be a spermatic granuloma. Since this was observed in a single animal, this is not considered to be treatment related. Several animals (one in control, one in 100 ppm group, one in 1200 ppm group) presented a purulent prostatitis which was of probable bacterial etiology.

Pregnancy rates, implantation data and implantation efficiency values and fetal death data for females mated to treated males were considered comparable to data for females mated to negative control males for each week of the post-treatment mating period. At dose level of 400 and 1200 ppm the test substance was not mutagenic in rats by the dominant-lethal test.

Positive control:

Females mated to the positive control males had fewer implants and lower implantation efficiency values (indicative of pre-implantation loss) than females mated to the negative control males. Fetal death parameters (mean and expressed as a percentage of total implants) for these same females were significantly increased during the post-treatment mating interval.

Conclusions:

Interpretation of results: negative

Under the conditions of the test no negative effects were induced by the test substance, hydrocarbons, C7-C9, isoalkanes.

Executive summary:

This data is being read across from the source study that tested Hydrocarbon C7-C9, isoalkanes based on analogue read across.

Under the conditions of the test no negative effects were induced by the test substance, hydrocarbons, C7 -C9, isoalkanes.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1980

Report date:

1980

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 478 (Genetic Toxicology: Rodent Dominant Lethal Test)

Principles of method if other than guideline:

Similar to OECD 478, only two dose levels were used.

GLP compliance:

not specified

Type of assay:

rodent dominant lethal assay

Test material

Test material information

Constituent 1

Reference substance name:

Hydrocarbons, C7-C9, isoalkanes

EC Number:

921-728-3

Cas Number:

64741-66-8

Molecular formula:

None available - not a single isomer - see remarks

IUPAC Name:

Hydrocarbons, C7-C9, isoalkanes

Details on test material:

- Name of test material (as cited in study report): MRD-78-26
- Molecular weight: 114 g/M
- Substance type: colourless liquid
- Physical state: colourless liquid
- Analytical purity: 100% pure commercial product
- Storage condition of test material: storage shed

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories, Wilmington, Massachusetts
- Age at study initiation: males: 10 weeks at initiation of pre-treatment mating period; females: 9 weeks at initiation of week 1 of pre-treatment mating period; females: 8 weeks at initiation of week 1 of post-treatment mating period
- Housing: males: individually housing during the treatment period; females: individually housing during the pre- and post-mating period
- Diet: Purina Laboratory Chow; ad libitum; except chamber-exposed groups during the treatment period
- Water: ad libitum; except chamber-exposed groups during the treatment period

Administration / exposure

Route of administration:

inhalation

Vehicle:

none

Details on exposure:

TYPE OF INHALATION EXPOSURE: whole body


GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: The stainless steel and glass chambers had a total volume of one cubic metre with an effective volume of 760 L.
- Air flow rate: 132 L/min
- Air change rate: every 7.6 min
- The test substance was placed in fritted-bottom, gas-washing bottles. Dry air, at various flow rates, was passed through the test material and the vapour-air mixtures entered the chamber air inlets and were further diluted with room air to provide the desired concentrations.


TEST ATMOSPHERE
Atmospheric sampling was performed using a Wilks Scientific Corp., Miran IA Ambient Air Analyzer (long pathlength infrared). On each exposure day three samples were drawn from each exposure chamber (at 1, 3 and 5 hours) and the exposure concentrations calculated by comparing the absorption of this sample to the standard curve.

Duration of treatment / exposure:

8 consecutive weeks

Frequency of treatment:

6 hours/day, 5 days/week

Post exposure period:

4 weeks

Doses / concentrations

Remarks:

Doses / Concentrations:
400 and 1200 ppm
Basis:
nominal conc.

No. of animals per sex per dose:

only males were exposed: 10/group

Control animals:

yes, sham-exposed

Positive control(s):

triethylenemelamine
- Route of administration: intraperitoneally on a single day, at least 2 hours prior to mating
- Doses level/ volume: 0.5 mg/kg body weight; 1 mL/kg body weight
- Vehicle: 0.9 % injectable normal saline solution

Examinations

Tissues and cell types examined:

Males: testes, seminal vesicles, epididymides, prostate tissues
Females: uteri

Details of tissue and slide preparation:

METHOD OF ANALYSIS:
Males: Seminal vesicles, epididymides, prostate and any abnormal lesion or tissue masses were preserved in 10 % neutral buffered formalin. Testes were stored for 48 hours in Bouin´s solution and subsequently placed in formalin. Tissues from 5 randomly chosen males from each group were examined.
Females: The uteri from all females (pregnant and non-pregnant) were appropriately identified and preserved intact in a 10 % neutral buffered formalin solution.

Statistics:

Comparisons were made during the treatment and post-treatment periods between negative control, positive control and test substance-treated groups by the Chi-square test. Absolute data were compared by using the F-test and Student´s t-test. When variances differed significantly, Student´s t-test was appropriately modified using Cochran´s approximation (t´). Corpora lutea and implantation data were evaluated by the one-tailed test.

Results and discussion

Test results

Key result

Sex:

male/female

Genotoxicity:

negative

Remarks:

At dose level of 400 and 1200 ppm the test substance was not mutagenic in rats by the dominant-lethal test.

Toxicity:

no effects

Vehicle controls validity:

other: no vehicle was used

Negative controls validity:

valid

Positive controls validity:

valid

Any other information on results incl. tables

No treatment-related effects were observed for mortality, in-life physical or necropsy examinations and for body weights in males.

No treatment effect was indicated from microscopic evaluation of testes, seminal vesicles, epididymides and prostate tissues from 5 randomly chosen males from each exposure group.

In one animal of the 400 ppm exposure group a caseous mass was observed in the left epididymis. This caseous mass was seen microscopically to be a spermatic granuloma. Since this was observed in a single animal, this is not considered to be treatment related. Several animals (one in control, one in 100 ppm group, one in 1200 ppm group) presented a purulent prostatitis which was of probable bacterial etiology.

Pregnancy rates, implantation data and implantation efficiency values and fetal death data for females mated to treated males were considered comparable to data for females mated to negative control males for each week of the post-treatment mating period. At dose level of 400 and 1200 ppm the test substance was not mutagenic in rats by the dominant-lethal test.

Positive control:

Females mated to the positive control males had fewer implants and lower implantation efficiency values (indicative of pre-implantation loss) than females mated to the negative control males. Fetal death parameters (mean and expressed as a percentage of total implants) for these same females were significantly increased during the post-treatment mating interval.

Applicant's summary and conclusion

Conclusions:

Interpretation of results: negative

Under the conditions of the test no negative effects were induced by the test substance, hydrocarbons, C7-C9, isoalkanes.

Executive summary:

Under the conditions of the test no negative effects were induced by the test substance, hydrocarbons, C7 -C9, isoalkanes.