Hydrocarbons, C10, aromatics, >1% naphthalene

Repeated dose toxicity: inhalation

Administrative data

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

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

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Source of data is from peer reviewed literature. Acceptable well-documented study report which meets basic scientific principles: non-GLP.

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:

sub-chronic toxicity: inhalation

Type of information:

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

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Source of data is from peer reviewed literature. Acceptable well-documented study report which meets basic scientific principles: non-GLP.

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

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

no effects observed

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Details on results:

RATS. One rat at the 0.10-mg/liter level died after 14 days. Death was attributed to a pneumonic infection as evidenced by extensive lung abscesses. None of the observations were dosage-related and are discounted for that reason.
Significant findings (Rats) - Concentration (mg/liter)
Specific gravity urine, 9 weeks, rats - 0.38 mg/liter - Not dosage-related;
Blood urea nitrogen, 3 weeks, rats 0.10 mg/liter - Not dosage related;
Red blood cell count, Packed cell volume, and Hemoglobin, 9 weeks, rats 0.38 mg/liter - Not dosage-related
Alkaline phosphatase, 9 weeks, rats 0.10 mg/liter - Not dosage-related;
Neutrophil differential, 13 weeks, rats 0.22 mg/liter - Not dosage-related;
Lymphocyte differential, 13 weeks, rats 0.22 mg/liter - Not dosage-related.

DOGS. Pre-exposure polymorphonuclear neutrophilic leucocytes for the 0.1 mg/liter dogs were slightly higher than the controls on an absolute basis, but on the basis of change from pre-exposure after 13 weeks of inhalation, there were no significant differences that were treatment related.

Key result

Dose descriptor:

NOAEC

Remarks:

Rat

Effect level:

> 0.38 mg/L air (analytical)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Systemic Toxicity

Key result

Dose descriptor:

NOAEC

Remarks:

Dog

Effect level:

> 0.38 mg/L air (analytical)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Systemic Toxicity

Critical effects observed:

not specified

Conclusions:

The test material’s NOAEC > 0.38 mg/liter (66 ppm), which was the highest achievable vapor concentration.

Executive summary:

This data is being read across from the source study that tested Hydrocarbons, C10, aromatics based on analogue read across.

Twenty-five male rats and four dogs per level were exposed for 6 hr/day, 5 days/wk for 13 wk. Another 20 rats, from the same week of production, were maintained for use as challenge exposure controls (naive rats). The challenge exposures were run to determine whether the 6-hr daily inhalation of a non-lethal level of hydrocarbon, would result in the rat becoming more or less resistant. One rat at the 0.10-mg/liter level died after 14 days. Death was attributed to a pneumonic infection as evidenced by extensive lung abscesses. None of the observations were dosage-related and are discounted for that reason. The test material’s NOAEC > 0.38 mg/liter (66 ppm), which was the highest achievable vapor concentration.

Data source

Reference

Reference Type:

publication

Title:

Petroleum hydrocarbon toxicity studies XIV. Animal and human response to vapors of "high aromatic solvent".

Author:

Carpenter CP, Geary DL Jr, Myers RC, Nachreiner DJ, Sullivan LJ, King JM.

Year:

1977

Bibliographic source:

Toxicol Appl Pharmacol. 1977 Aug;41(2):235-49.

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 413 (Subchronic Inhalation Toxicity: 90-Day Study)

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Hydrocarbons, C10, aromatics

IUPAC Name:

Hydrocarbons, C10, aromatics

Test animals

Species:

other: Rats and Dogs

Strain:

other: RATS: Harlan Wistar; DOGS: Beagles

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: RATS: Harlan
-Number: RATS: 25 males; DOGS: 4 males

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

25 rats and four dogs per dose were used.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Gas chromatographic analyses of the nominal 0.25, 0.5, and 1.0 mg/liter vapor-air mixtures yielded mean measured concentrations of 0.10, 0.22, and 0.38 mg/liter or 17, 38, and 66 ppm.

Doses / concentrations

Remarks:

Doses / Concentrations:
17, 38, and 66 ppm (0.10, 0.22, 0.38 mg/L)
Basis:
analytical conc.

No. of animals per sex per dose:

RATS: 6 males/dose (25 total); DOGS: 1 male/dose (4 total)

Details on study design:

Methods

Species and number. Twenty-five male rats and four dogs per level were used. Another 20 rats, from the same week of production, were maintained for use as challenge exposure controls (naive rats). The challenge exposures were run to determine whether the 6-hr daily inhalation of a non-lethal level of hydrocarbon, whether by acclimatization or induction of enzymes, would result in the rat becoming more or less resistant than non-exposed or naive controls from the same lot of animals.

Concentrations. A control group (exposed to dilution air) plus groups exposed to three graded levels of test material were utilized for each compound.

Duration. Exposures were 6 hr/day, 5 days/wk for 13 wk.

Observations. Once each week, body weights of both species and food consumption for dogs were determined. Overall appearance and behavior were checked daily.

Procedure. At 3, 8, and 13 wk of exposure three, three, and four rats, respectively, from each group, including controls, were sacrificed. After 13 wk of exposure 10 surviving rats from each group and 20 unexposed rats of the same age were used to detect any significant differences in time to death or in occurrence of signs of distress among the groups. The groups were “challenged” simultaneously by exposure to a vapor air concentration 1.25-2 times the 4-hr rat LC50 until 25 % of the group succumbed or for no more than a 6-hr period. The remaining rats, or those surviving the subacute exposure, exclusive of the ten per level reserved for the challenge exposure were sacrificed after 13 wk and tissues were taken for histopathological interpretation following gross autopsy. The assignment of rats to each of the above groups was made by random selection before the start of the study.

Clinical and hematological schemata. These tests were performed on all dogs initially and prior to sacrifice; and on rats, prior to sacrifice at 3, 8, and 13 wk of exposure. Minimum hematological evaluation for each animal included hematocrit, total erythrocyte count, reticulocyte count, and total and differential leucocyte counts. The biochemical survey included serum alkaline phosphatase, serum glutamic oxoacetic transaminase, serum glutamic pyruvic transaminase, and blood-urea-nitrogen on the rats, and these tests plus bilirubin and blood glucose on the dogs. Initial pre-terminal electrocardiograms were performed on all dogs. Urinalyses were conduct with both species.

Autopsy and pathology schemata. Gross examinations were made of all organ system Histopathological examination included brain (three sections), respiratory (three sections minimum, based on acute exposure data results), heart, thyroid, live kidney, adrenal, spleen, pancreas, stomach and intestines, skeletal muscle, bat marrow, and peripheral nerves. The reproductive organs and eyes were not scheduled for histopathological study unless abnormalities were discovered upon gross examination. Tissues were taken from all dogs and from rats sacrificed after 3, 8, and 13 wk of inhalation of the vapor.

Examinations

Observations and examinations performed and frequency:

Observations. Once each week, body weights of both species and food consumption for dogs were determined. Overall appearance and behavior were checked daily.

Clinical and hematological schemata. These tests were performed on all dogs initially and prior to sacrifice; and on rats, prior to sacrifice at 3, 8, and 13 wk of exposure. Minimum hematological evaluation for each animal included hematocrit, total erythrocyte count, reticulocyte count, and total and differential leucocyte counts. The biochemical survey included serum alkaline phosphatase, serum glutamic oxoacetic transaminase, serum glutamic pyruvic transaminase, and blood-urea-nitrogen on the rats, and these tests plus bilirubin and blood glucose on the dogs. Initial pre-terminal electrocardiograms were performed on all dogs. Urinalyses were conduct with both species.

Sacrifice and pathology:

Autopsy and pathology schemata. Gross examinations were made of all organ system. Histopathological examination included brain (three sections), respiratory tract (three sections minimum, based on acute exposure data results), heart, thyroid, live kidney, adrenal, spleen, pancreas, stomach and intestines, skeletal muscle, bone marrow, and peripheral nerves. The reproductive organs and eyes were not scheduled for histopathological study unless abnormalities were discovered upon gross examination. Tissues were taken from all dogs and from rats sacrificed after 3, 8, and 13 wk of inhalation of the vapor.

Statistics:

Statistical analysis. Based on mortality during a 14-day observation period, the most probable LC50 with its fiducial range was calculated by the Thompson method of moving averages using tables by Weil (1952) and other unpublished tables. The results of the quantitative continuous variables, such as body weight changes, were intercompared for the dosage groups and the controls by the use of the following tests: Bartlett’s homogeneity of variance, analysis of variance, rank sum, and Duncan’s multiple range. The latter was used, if F for analysis of variance was significantly high, to delineate which groups differed from the controls. If Bartlett’s test indicated heterogeneous variances, the F test was used for each group versus the control. If these individual F tests were not significant, Student’s t test was used; if significant, the means were compared by the Cochran t test or the rank sum test. Frequency data, such as incidences of mortality or of micro-pathological conditions, were intercompared by the normal deviate of chi square calculated with Yates’ correction for continuity. In all cases the fiducial limit of 0.05 was employed to delineate the critical level of significance.
In general, only criteria that differed statistically significantly from the control group are discussed. Omission of comment is indicative that no valid differences were found. An attempt has been made to round off machine calculated data but if it is obvious that the data portend fictitious accuracy the implication should be ignored.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

no effects observed

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Details on results:

RATS. One rat at the 0.10-mg/liter level died after 14 days. Death was attributed to a pneumonic infection as evidenced by extensive lung abscesses. None of the observations were dosage-related and are discounted for that reason.
Significant findings (Rats) - Concentration (mg/liter)
Specific gravity urine, 9 weeks, rats - 0.38 mg/liter - Not dosage-related;
Blood urea nitrogen, 3 weeks, rats 0.10 mg/liter - Not dosage related;
Red blood cell count, Packed cell volume, and Hemoglobin, 9 weeks, rats 0.38 mg/liter - Not dosage-related
Alkaline phosphatase, 9 weeks, rats 0.10 mg/liter - Not dosage-related;
Neutrophil differential, 13 weeks, rats 0.22 mg/liter - Not dosage-related;
Lymphocyte differential, 13 weeks, rats 0.22 mg/liter - Not dosage-related.

DOGS. Pre-exposure polymorphonuclear neutrophilic leucocytes for the 0.1 mg/liter dogs were slightly higher than the controls on an absolute basis, but on the basis of change from pre-exposure after 13 weeks of inhalation, there were no significant differences that were treatment related.

Effect levels

1

Key result

Dose descriptor:

NOAEC

Remarks:

Rat

Effect level:

> 0.38 mg/L air (analytical)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Systemic Toxicity

2

Key result

Dose descriptor:

NOAEC

Remarks:

Dog

Effect level:

> 0.38 mg/L air (analytical)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Systemic Toxicity

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

The test material’s NOAEC > 0.38 mg/liter (66 ppm), which was the highest achievable vapor concentration.

Executive summary:

Twenty-five male rats and four dogs per level were exposed for 6 hr/day, 5 days/wk for 13 wk. Another 20 rats, from the same week of production, were maintained for use as challenge exposure controls (naive rats). The challenge exposures were run to determine whether the 6-hr daily inhalation of a non-lethal level of hydrocarbon, would result in the rat becoming more or less resistant. One rat at the 0.10-mg/liter level died after 14 days. Death was attributed to a pneumonic infection as evidenced by extensive lung abscesses. None of the observations were dosage-related and are discounted for that reason. The test material’s NOAEC > 0.38 mg/liter (66 ppm), which was the highest achievable vapor concentration.