2-ethylhexanal

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to OECD 403 under GLP conditions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

no

GLP compliance:

yes

Remarks:

BIBRA toxicology international

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-ethylhexanal

EC Number:

204-596-5

EC Name:

2-ethylhexanal

Cas Number:

123-05-7

Molecular formula:

C8H16O

IUPAC Name:

2-ethylhexanal

Details on test material:

- Analytical purity: 2-ethylhexanal 97.96% determined with GC
- Impurities (identity and concentrations): 2-ethylhexenal 0.11 %, 2-ethylhexanol 0.05 %, water 0.34 %
Identity of 2-ethylhexanal confirmed using 1H-NMR spectrum

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Olac Ltd., Bicester, Oxon, UK
- Weight at study initiation: approximately 150 g
- Fasting period before study: no fasting
- Housing: polypropylene cages with stainless-steel mesh tops and floors suspended over paper for the removal of excreta
- Diet: ad libitum except chamber acclimatisation and exposure
- Water: ad libitum except chamber acclimatisation and exposure
- Acclimation period: 4 h daily exposure to air alone, on 3 d prior to study


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24
- Humidity (%): 45-70
- Air changes (per hr): at least 15
- Photoperiod (hrs dark / hrs light): 12/12 (06.00 - 18.00 GMT/18.00 - 06.00 GMT)

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION (Limit2)
- Exposure apparatus: all-glass inhalation chamber
- Exposure chamber volume: 70 l
- Method of holding animals in test chamber: stainless-steel wire mesh cage
- Source and rate of air: 40 l/min
- System of generating aerosols: steady infusion of the material into a concentric jet atomiser through which 40 l/min of air was passed. Atmosphere was passed into a mixing vessel in heating mantle (100 °C) containing glass fibre filter pads.


TEST ATMOSPHERE
- Brief description of analytical method used: gas-liquid chromatography
- Samples taken from breathing zone: yes

Analytical verification of test atmosphere concentrations:

yes

Remarks:

Concentration within the exposure chamber was measured using gas-liquid chromatography

Duration of exposure:

4 h

Concentrations:

Two Limit tests (Limit 1+2) were performed (nominal concentrations):
-Limit 1: 6.4 +/- 0.43 mg/L (1199 +/- 80.5 ppm)
-Limit 2: 10.68 mg/L (2000 ppm)
Analytical concentrations:
-Limit1: 1.62 +/- 1.20 mg/L (303 +/- 224.7 ppm)
-Limit2: 6.83 +/- 1.32 mg/L (1279 +/- 247 ppm)

LIMIT2: maximum concentration exceeds 5 mg/L (936 ppm) requiered under OECD 403

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:
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: observations each day, frequent observation of variation of conditions and behaviour; weighing on days -3, 0, 1, 2, 7, 14
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight, histopathology

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 6.83 mg/L air

Exp. duration:

4 h

Remarks on result:

other: No mortality observed within 4 h - vapor was tested

Mortality:

No mortality observed

Clinical signs:

other: During exposure: gradual reduction in respiratory rate combined with reduction to noise stimuli (most severe at 2 h of exposure) Irritations of the mucosa, nostrils and eyes (closed) had reddish-brown colouration, reversible within 3 d

Body weight:

Weight reduction for 2 d after exposure followed by a weight increase. Overall body weight development was positive.

Gross pathology:

Pale pink to deep-red colouration of the lungs (all animals), pale kidneys (2x males), opaque eyes with a small milky area (1x male)

Applicant's summary and conclusion

Executive summary:

Study is conducted under GLP conditions and according to OECD guideline 403 (valid without restrictions). 5 Rats/sex were exposed for 4 h to 6.83 mg/L (vapour). No mortality occurred. Observed clinical effects and necropsy findings point to irritating properties of the substance.

Conclusion:

Acute inhalative toxicity LD50 > 6.83 mg/L/4h.