1,1-dimethylheptanethiol

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1986-11-26 to 1986-12-12

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This study was classified as reliable without restriction because it appears to have followed the recommendations of OECD Guideline 403.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1987

Report date:

1987

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

1,1-dimethylheptanethiol (CAS # 25360-10-5)

IUPAC Name:

1,1-dimethylheptanethiol (CAS # 25360-10-5)

Details on test material:

- Name of test material (as cited in study report): t-nonyl mercaptan
- Substance type: Heavy Mercaptan
- Physical state: Liquid
- Analytical purity: Not reported
- Lot/batch No.: 1.31
- Storage condition of test material: Under ambient temperature and humidity in dark

Test animals

Species:

rat

Strain:

other: Crl:CD(SD) BR

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (U.K.) Ltd., Margate
- Age at study initiation: 6 to 8 weeks old
- Weight at study initiation: 180 to 200 grams
- Fasting period before study: none
- Housing: In groups of 5 within grid-floor cages
- Diet (e.g. ad libitum): ad libitum except during exposure
- Water (e.g. ad libitum): ad libitum except during exposure
- Acclimation period: 6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 °C to 25°C
- Humidity (%): 40% to 70%
- Air changes (per hr): 15/hr
- Photoperiod (hrs dark / hrs light): 12 hrs dark/12 hrs light

IN-LIFE DATES: From: 1986-11-20 To: 1986-12-12

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

head only

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Hazleton modified heated 'J-Tube' generator
- Exposure chamber volume: 10 Liters
- Method of holding animals in test chamber: Restraining tubes
- Source and rate of air: Filtered air from a compressed air supply at 11.6 to 13 L/minute
- Method of conditioning air: Filtered
- Temperature, humidity, pressure in air chamber: 19°C to 22°C; 43% to 66%

TEST ATMOSPHERE
- Brief description of analytical method used: The concentration of the test article was determined twice-hourly by sampling through a Miran 1A infra-red gas analyzer set at a wavelength of 3.39 µm and a path-length of 0.75m. The instrument was calibrated by injection of known volumes of the liquid test article in to the gas analyzer and a curve plotted of absorbance versus calculated concentration. The calibration of the instrument was checked before the exposure.
- Samples taken from breathing zone: yes

Analytical verification of test atmosphere concentrations:

yes

Remarks:

twice hourly

Duration of exposure:

ca. 4.5 h

Remarks on duration:

Owing to a transient drop in the chamber atmosphere concentration, the exposure period for the treated group was increased by half an hour t o 4.5 hours.

Concentrations:

Measured concentration: 0 and 1074 ppm (7.04 mg/L or 7041 mg/m3)
Nominal concentration: 0 and 1585 ppm (10.39 mg/L or 10391 mg/m3)

No. of animals per sex per dose:

5

Control animals:

yes

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Observations - hourly during exposure and on day of exposure, one daily thereafter for 14 days; Body weight - Immediately prior to and after exposure; on observation days 7 and 14; and immediately prior to termination
- Necropsy of survivors performed: yes
- Other examinations performed: histopathology

Statistics:

mean and standard deviations were determined where appropriate

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

>= 7.04 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4.5 h

Remarks on result:

other: = 7041 mg/m3 of 1074 ppm

Mortality:

No mortality was observed in either male or female rats through the course of the study

Clinical signs:

other: Marked clinical signs of pilo-erection, ataxia, transient salivation and wet fur were observed for all treated animals. These signs were not apparent in control animals.

Body weight:

No treatment-related effects on body weight were observed in either male or female rats.

Gross pathology:

No gross or histopathological signs of specific organ toxicity were observed in any of the treated animals.

Applicant's summary and conclusion

Interpretation of results:

not classified

Remarks:

Migrated information the single concentration tested (7.04 mg/L) produced no mortality Criteria used for interpretation of results: EU

Conclusions:

In an acute inhalation toxicity study, groups of Crl:CD(SD)BR strain rats (5/sex) were exposed by inhalation route to 1,1-dimethylheptanethiol for 4.5 hours at a concentration of 7.04 mg/L.  The inhalation LC50 was determined to be > 7.04 mg/L in rats.

Executive summary:

In an acute inhalation toxicity study, Crl:CD(SD)BR strain rats (5/sex) were exposed via inhalation (head only) to 1,1-dimethylheptanethiol for 4.5 hours at a concentration of 7.04 mg/L. Animals were subsequently observed for a period of 14 days.

No mortality was observed in either male or female rats through the course of the study. Marked clinical signs of pilo-erection, ataxia, transient salivation and wet fur were observed for all treated animals. These signs were not apparent in control animals. No treatment-related effects on body weight were observed in either male or female rats. No gross or histopathological signs of specific organ toxicity were observed in any of the treated animals. Based on the lack of treatment-related signs of clinical toxicity, the acute inhalation LC₅₀ for 1,1-dimethylheptanethiol was determined to be > 7.04 mg/L.

This study received a Klimisch score of 1 and is classified reliable without restriction because it appears to have followed the recommendations of OECD Guideline 403.