Naphthalene

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1985

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study according to OECD guideline.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1985

Report date:

1985

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: EPA TSCA

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

Remarks:

: A limit test was performed but the highest achievable concentration was approximately 0.4 mg/L rather than 2 mg/L.

Test guideline 3

Qualifier:

equivalent or similar to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

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

Details on test material:

- Name of test material (as cited in study report): Naphthalene
- Substance type: Polycyclic aromatic hydrocarbon
- Physical state: Solid, but liquid at 101°C
- Analytical purity: Provided as 100%
- Impurities (identity and concentrations): None
- Composition of test material, percentage of components: Provided as 100% naphthalene
- Purity test date:
- Lot/batch No.: 5601-56-1, Order J-299
- Expiration date of the lot/batch: 1986
- Stability under test conditions: Stable to boiling point (218°C)
- Storage condition of test material: Room temperature

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

NAME:
- Name: Hilltop-Wistar Albino rats, (HLA(WI)BR

SOURCE:
- Age at study initiation: Male 48 days, female 62 days
- Weight at study initiation: Males 269 – 290, Females 240 - 265
- Fasting period before study: None
- Housing: 2 to 3 per sex
- Diet (e.g. ad libitum): ad libitum, except during exposure
- Water (e.g. ad libitum): ad libitum, except during exposure
- Acclimation period: 8 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 – 22°C
- Humidity (%): 30 – 44%
- Air changes (per hr):
- Photoperiod (hrs dark / hrs light): 12/ dark/12light

IN-LIFE DATES:
- From: To: 2/13/1985 to 2/27/1985 (day of exposure to death)

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

other: Air, filtered compressed

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION:
- Exposure apparatus: Naphthalene was generated using a Compact Tube Furnace. Seven ampoules containing a known amount of naphthalene were placed in the furnace tube at overlapping times and heated at a mean temperature of 101±4°C. Filtered compressed air was passed through a desiccant prior to entering the furnace tube. This air then entered the chamber holding the animals. The resulting chamber airflow rate was 25 litres per minute
- Exposure chamber volume: 120 L
- Method of holding animals in test chamber: Individually housed in 21 x 12.5x 18 cm stainless steel wire-mesh cages held in a cuboidal Plexiglas chamber
- Source and rate of air: 25 L/minute
- Method of conditioning air: Filtered compressed air passed through a desiccant prior to entering furnace tube.
- Treatment of exhaust air: None
- Temperature, humidity, pressure in air chamber: Temperature 24°C, Humidity 49%

TEST ATMOSPHERE:
- Brief description of analytical method used: Perkin-ElmerSigma 2000 gas chromatograph (GC) with flame ionization detector. Column 10% SP 2100 on 80/100 Suplecoport. Column temperature 180°C. Carrier nitrogen with hydrogen and air.
- Samples taken from breathing zone: yes

VEHICLE (if applicable):
- Composition of vehicle (if applicable): Not applicable
- Concentration of test material in vehicle (if applicable): Not applicable
- Justification of choice of vehicle: Not applicable
- Lot/batch no. (if required): Not applicable
- Purity: Not applicable

CLASS METHOD (if applicable)
- Rationale for the selection of the starting concentration: Highest achievable vapour concentration

Analytical verification of test atmosphere concentrations:

yes

Remarks:

every 30 minutes. Perkin-ElmerSigma 2000 gas chromatograph (GC) with flame ionization detector. Column 10% SP 2100 on 80/100 Suplecoport. Column temperature 180°C. Carrier nitrogen with hydrogen and air.

Duration of exposure:

4 h

Concentrations:

77.7 ppm, ~ 0.4 mg/L (highest concentration technically achievable)

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days (or other?) 14 days
- Frequency of observations and weighing: Clinical prior to exposure, during exposure and daily for 14 days: Weekly weights
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight, organ weights, histopathology, other: Clinical signs, body weights, gross pathology.

Statistics:

Mean and standard deviations for body weights, body weight changes, exposure concentrations, temperature and humidity.

Results and discussion

Effect levels

Effect levels 1

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 77.7 ppm

Based on:

other: 100% naphthalene

Exp. duration:

4 h

Remarks on result:

other: Clinical signs observed on the day of exposure included closed eyes, lacrimation and mouth breathing.

Effect levels 2

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 0.4 mg/L air (analytical)

Based on:

other: 100% naphthalene

Exp. duration:

4 h

Remarks on result:

other: Clinical signs observed on the day of exposure included closed eyes, lacrimation and mouth breathing.

Effect levels 3

Sex:

male/female

Dose descriptor:

LC0

Effect level:

77.7 ppm

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No effect

Clinical signs:

other: Clinical signs observed on the day of exposure included closed eyes, lacrimation and mouth breathing. No effects on post-treatment day 7 or 14.

Body weight:

No effect

Gross pathology:

No effect

Applicant's summary and conclusion

Interpretation of results:

other: The toxicity category cannot be determined because the highest achievable dose was 0.4 mg/L.

Remarks:

Criteria used for interpretation of results: expert judgment

Conclusions:

Not toxic at highest attainable concentration of 0.4 mg/L.

Executive summary:

A single four-hour exposure of 77.7 ppm of naphthalene produced no mortality. Clinical signs observed for both sexes during the exposure period included signs of ocular and respiratory irritation. There were no clinical signs observed following the exposure or during the 14-day post-exposure period. Body weight gains were observed for all animals except for one female on post-exposure day seven considered to be non-treatment related. No exposure-related gross pathologic lesions were observed at necropsy. The results of this study indicate that the LC₅₀ for naphthalene vapour in Wistar albino rats is greater than 77.7 ppm, (0.4 mg/L) naphthalene. The 77.7 ppm concentration was the highest naphthalene vapour concentration obtainable under the conditions of the study.