Acetaldehyde

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: well documented non GLP study report that is similar to OECD Guideline 403

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1981

Report date:

1981

Reference 2

Reference Type:

publication

Title:

INHALATION TOXICITY OF ACETALDEHYDE IN RATS. I. ACUTE AND SUBACUTE STUDIES

Author:

LMI. APPELMAN, R.A. WOUTERSEN and V.J. FERON

Year:

1982

Bibliographic source:

Toxicology, 23 (1982) 293-307

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

GLP compliance:

not specified

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Acetaldehyde

EC Number:

200-836-8

EC Name:

Acetaldehyde

Cas Number:

75-07-0

Molecular formula:

C2H4O

IUPAC Name:

acetaldehyde

Details on test material:

Acetaldehyde (grade: for sythesis) was obtained from Merck-Schuchardt, Germany

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Central institute for breeding of Laboratory animals TNO, Zeist, Netherlands.
- Age at study initiation: no data
- Weight at study initiation (mean): 191 g and 149 g for males and females respectively
- Fasting period before study: no data
- Housing: per sex, five to a cage
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: no data


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22+/-1 °C
- Humidity (%): 40-60%
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: The animals were exposed in horizontally placed glass exposure cylinders, fitted with an interior of perforated stainless steel plate to separately accommodate ten rats.
- Exposure chamber volume: cylinder with 0.9x0.15 m
- Method of holding animals in test chamber: see above
- Source and rate of air: 8 l/min
- Method of conditioning air: filtered and dried nitrogen was passed through a glass evaporator filled with acdtaldehyde kept at a temperature of 4 °C. To obtain the desired acetaldehyde concentration in the test atmosphere the nitrogen flow loaded with acetaldehyde was miced in the proper ratio with the main airflow passed through the exposure chambers.
- Temperature, humidity, pressure in air chamber: 23 °C

TEST ATMOSPHERE
- Brief description of analytical method used: gaschromatography (Intersmat GC 120) with a flame ionistation detector

DOSE SELECTION
available data from Syrian hamster (Kruysse, 1970): LC50 31 g/m3; 4 h

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

10436 ppm, 12673 ppm, 15683 ppm, 16801 ppm

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: subsequent obervation; weighing at day 0, 1, 2, 4, 7, 14
- Necropsy of survivors performed: no
- Other examinations performed: clinical signs, body weight,organ weights, histopathology, other:

Statistics:

The 4 hour LC50 and the 95% confidence limit were calculated according to Finney (1971)

Results and discussion

Effect levels

Effect levels 1

Sex:

male/female

Dose descriptor:

LC50

Effect level:

13 300 ppm

95% CL:

11 200 - 15 400

Exp. duration:

4 h

Effect levels 2

Sex:

male/female

Dose descriptor:

LC50

Effect level:

24 040 mg/m³ air

95% CL:

20 250 - 27 840

Exp. duration:

4 h

Mortality:

All animals that died, died within a period of 2 days after termination of the exposure, except for one animal exposed to the 15683 ppm acetaldehyde that died on day 6 of the observation period.

Clinical signs:

other: During the first half an hour of the exposure period the animals were restless, kept their eyes closed and showed a laboured respiration. After approximately one hour the animals were lying with their eyes open and showed severe mouth breathing.

Body weight:

Both males and females lost body weight during the first day of the observation period. Thereafter they gained weight in a normal way, exept for the females of the 15683 ppm group, which gained weight in a normal way nut until the second week.

Gross pathology:

no data

Other findings:

-

Any other information on results incl. tables

Table 1.Overview on the deaths (male and female) during the exposure period and the complete experiment, respectively.

 

concentration[ppm]	Number of deaths during exposure	Number of deaths during the complete experiment	Total mortality [%]
10436	1	1	20
12673	-	5	50
15683	2	7	60
16801	6	8	80

 

Applicant's summary and conclusion

Conclusions:

Acetaldehyde has a low toxicity after inhaltion under the reported conditions. The LC 50 (4h) is 24.04 mg/L.

Executive summary:

Acetaldehyde was investigated for inhalation toxicity in an experimental study that was similar to OECD Guideline 403. From the observed mortalities after 4 hours exposure the LC 50 was calculatad as 24.04 mg/L (13300 ppm). Acetaldehyde could thus be considered as of low toxicity when inhaled.