Naphthalene

Toxicity to reproduction

Administrative data

Endpoint:

toxicity to reproduction

Remarks:

other: subchronic

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study performed according to EPA and OECD guideline

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Materials and methods

Test guideline

Test guideline 1

Qualifier:

equivalent or similar to guideline

Guideline:

other: EPA OPP 82-4 (90-Day Inhalation Toxicity)

Deviations:

no

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

no

Remarks:

but no recovery groups included

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Naphthalene

EC Number:

202-049-5

EC Name:

Naphthalene

Cas Number:

91-20-3

Molecular formula:

C10H8

IUPAC Name:

naphthalene

Test material form:

solid: crystalline

Details on test material:

- Name of test material (as cited in study report): Naphthalene
- Substance type: Aromatic hydrocarbon
- Physical state: Grey-white crystalline solid
- Analytical purity: Assumed to be pure
- Impurities (identity and concentrations): None provided
- Lot/batch No.: LI-1 (LX No: LX158-01)
- Expiration date of the lot/batch: (a) 27 April 1993, (b) 25 June 1993
- Stability under test conditions: Stable
- Storage condition of test material: Room temperature

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

SOURCE:
- Age at study initiation: 8 ½ weeks
- Weight at study initiation: Male 221 – 272g; female 155 – 190g
- Fasting period before study: None
- Housing: Group housed 5/sex/cage
- Diet: ad libitum (while in cages)
- Water: ad libitum
- Acclimation period: 18 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 – 22°C
- Humidity (%): 30 – 67
- Air changes (per hr): Not provided
- Photoperiod (hrs dark / hrs light): 12 hr dark / 12 hr light

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure (if applicable):

nose only

Vehicle:

clean air

Details on exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION:

-Exposure apparatus: Nose only inhalation chamber (ADG Instruments) with 20 exposure ports and a top section incorporating a tangential air inlet.Each chamber was assembled in 3 sections and formed a 28 cm diameter cylinder with a volume of approximately 50 litres. A separate exposure chamber was used for each group.
- Method of holding animals in test chamber: Molded polycarbonate tubes tapered at one end to allow the nose-only of the rat to protrude from the tapered end of the chamber. The other end was closed by insertion of an expanded plastic bung.
- Source and rate of air: Air was withdrawn from the base of the chamber at a rate of 30 litres/minute. The air was withdrawn by a vacuum pump through filtration media, to remove particulate, and a silica gel to remove excess moisture. The air supply to the chamber was comprised of a carrier (vapour) and a diluent air supply, to a total of 25 litres/minute to allow the exposure chamber to be maintained at a slight negative pressure.
- Method of conditioning air: See above
- System of generating particulates/aerosols: A separate vapour generation system was used for each group. It consisted of a 3-necked round bottom flask containing an aliquot of the test substance. Air was passed through the flask and vapour-laden air passed out through a second neck. The third neck contained a thermometer. At lower concentrations the test atmosphere was generated under ambient temperatures using the carrier airflow to maintain the concentration. At higher concentrations the test substance flask and carrier air was heated in a water bath to assist vaporisation. The vapour-laden air was passed through a clear plastic tube with glass wool (particulate trap) and mixed with diluent air (where applicable) before entering the chamber.
- Temperature, humidity, pressure in air chamber: Temperature 19.7 – 20.1°C; Humidity 45 – 52%; Oxygen concentration 21%
- Air flow rate: 30 litres/minute
- Air change rate: (30 l/min)/50 l; 36/hour
- Method of particle size determination: Not applicable

TEST ATMOSPHERE:
- Brief description of analytical method used: GC analysis of samples reacted with carbon disulfide. Column: 2mm x 1m i.d. glass packed with 10% OV-101 (80 -100 mesh). Column conditions: temperature- injector 200°C, column 120°C, detector 250°C. Gases: helium 30ml/min, hydrogen 33 ml/min, air 300ml/min: Retention time for Naphthalene 1.3 minutes.
- Samples taken from breathing zone: Yes

VEHICLE (if applicable):
- Justification for use and choice of vehicle: Air; Not applicable

Details on mating procedure:

No mating occured

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Samples taken at 1, 3 and 5 hours for all treatment groups during each exposure.
Brief description of analytical method used: GC analysis of samples reacted with carbon disulfide. Column: 2mm x 1m i.d. glass packed with 10% OV-101 (80 -100 mesh). Column conditions: temperature- injector 200°C, column 120°C, detector 250°C. Gases: helium 30ml/min, hydrogen 33 ml/min, air 300ml/min: Retention time for Naphthalene 1.3 minutes.
Samples taken from breathing zone: Yes

Duration of treatment / exposure:

13 consecutive weeks

Frequency of treatment:

Six hours exposure for 5 days a week

Details on study schedule:

No data

Doses / concentrations

Remarks:

Doses / Concentrations:
Target 2, 10, 60 ppm: analysed 2, 10, 58 ppm (11, 52, and 304 mg/m3)
Basis:
analytical conc.

No. of animals per sex per dose:

10/sex/dose

Control animals:

yes, concurrent vehicle

Details on study design:

Dose selection rationale: 4 week inhalation study
Rationale for animal assignment (if not random): Computer distribution based on body weight
Rationale for selecting satellite groups: None

Positive control:

none

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Twice a day
- Cage side observations checked in table [No. 9.1] were included.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Weekly

BODY WEIGHT: Yes
- Time schedule for examinations: Weekly

FOOD CONSUMPTION:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes, Weekly

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: Not calculated but data present

WATER CONSUMPTION: No

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: Prior to allocation and during week 13
- Dose groups that were examined: All

HAEMATOLOGY: Yes
- Time schedule for collection of blood: Week 13
- Anaesthetic used for blood collection: Yes, light ether anaesthesia
- Animals fasted: Yes
- How many animals: All
- Parameters checked in table [No. 9.7] were examined. PCV, Hb, RBC, MCHC, MCV, WBC, Diff, Plts, TT, Retic, and P, H, A, and R.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Week 13
- Animals fasted: Yes
- How many animals: All
- Parameters checked in table [No. 9.8] were examined. CPK, glucose, GPT, GOT, g-GT, AP, total protein, Alb, Glob, Urea Nitr, total bilirubin, creatine, NA, K, Ca, P, Cl, and Chol.

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

Oestrous cyclicity (parental animals):

No data

Sperm parameters (parental animals):

No data

Litter observations:

No litters produced

Postmortem examinations (parental animals):

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes

Postmortem examinations (offspring):

No offspring produced

Statistics:

Bartlett’s for homogeneity, if heterogeneous then Kruskal-Wallis. Analysis of variance (Student’s t test) for dose response.

Reproductive indices:

No data

Offspring viability indices:

No data

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

3 deaths but not related to treatment. Increase in brown staining of fur but not considered toxicologically significant.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Reduced body weight gain at 58 ppm in males and females. Reduced body weight gain at 10 ppm in males.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

Reduced body weight gain at 58 ppm in males and females. Reduced body weight gain at 10 ppm in males.

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

See "details on results".

Other effects:

not specified

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

not examined

Details on results (P0)

Histopathology non-neoplastic:

Degenerative changes in the olfactory epithelium including slight disorganisation, occasional degenerated cells, atrophy and erosion. The changes were more severe at 10 and 58 ppm and generally less severe at mild grades of individual lesions at 2 ppm. Subepithelial effects were observed in Bowman’s glands.
Proliferative lesions of the olfactory epithelium at the 58 ppm dose included hyperplasia of basal cells, rosette formation, hyperplasia (with loss of olfactory features), and in a single case early squamous metaplasia. The dose response of the proliferative lesions was not as obvious as of the degenerative changes due to the fact that continuous degenerative damage at the 60 ppm level resulted in increased cell death, thus restricting the proliferative (reparative) changes.

Effect levels (P0)

1

Dose descriptor:

NOAEC

Remarks:

(highest exposure level tested)

Effect level:

306 mg/m³ air (analytical)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Histopathology of reproductive organs: testes, epididymis, ovaries, uterus, oviduct along with reproductive organ weights (testes with epididymides, prostate, ovaries)

2

Dose descriptor:

LOAEC

Effect level:

0.011 mg/L air

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Histopathology: local degenerative effects in the olfactory region - atrophy, hyperplasia of epithelium, loss of Bowman´s glands

3

Dose descriptor:

LOAEC

Effect level:

2 ppm (analytical)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: see histopathologic effects above

Results: F1 generation

General toxicity (F1)

Clinical signs:

not specified

Mortality / viability:

not specified

Body weight and weight changes:

not specified

Sexual maturation:

not specified

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

not specified

Histopathological findings:

not specified

Details on results (F1)

No production of offspring.

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

Table 1: Macroscopic pathology incidence summary – terminal kill (from Report, Table 8)

(Note: Only organs showing any anomalies are included)

Females	Group 1	Group 2	Group 3	Group 4
Animals on study	10	10	10	10
Animals completed	10	9	10	10
Uterus Fluid distension	1	3	1	2

Males	Group 1	Group 2	Group 3	Group 4
Animals on study	10	10	10	10
Animals completed	9	9	10	10
Epididymides Yellow swellings	0	0	0	1

Table 2: Microscopic pathology incidence summary (from Report, Table 10)

(Note: Only organs showing any anomalies are included)

	Group 1	Group 2	Group 3	Group 4
Animals on study	10	10	10	10
Animals completed	10	10	10	10
Uterus
Examined	10	4	1	10
No abnormalities detected	9	0	0	8
Luminal dilatation (total)	1	4	1	2
Moderate	1	3	1	2
Marked	0	1	0	0
Ovaries
Examined	10	0	0	10
No abnormalities detected	10	0	0	8
Cystic corpus luteum	0	0	0	1
Cystic follicles	0	0	0	1
Epididymides
Examined	10	0	0	10
No abnormalities detected	10	0	0	9
Sperm granuloma	0	0	0	1
Testes
Examined	10	0	0	10
No abnormalities detected	10	0	0	8
Atrophy (total)	0	0	0	1
Minimal	0	0	0	1
Tubular atrophy (total)	0	0	0	1
Minimal	0	0	0	1

 

Applicant's summary and conclusion

Conclusions:

Conclusion: Regardless of the route of exposure, no effect in the rat on reproductive organs was found in sub-chronic studies.

Executive summary:

Ten male and ten female CRL:CD®(SD)BR Sprague-Dawley rats were exposed nose-only to 0, 2, 10, and 60 (58 measured) ppm for six hours a day for five days a week for 13 consecutive weeks. Detailed macroscopic examinations of each rat was performed and organ weights of ovaries, prostate, testes with epididymides were controlled. Microscopic examination of testes plus epididymides, prostate, seminal vesicles, uterus (corpus plus cervix), oviduct and ovaries was performed. No treatment-related effects or alteration in any reproductive organ was found (testes, epididymides, uterus, cervix, ovaries, and oviducts) after exposure to naphthalene by inhalation.