Pentane-2,4-dione

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: Acceptable, well-documented study report.

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1986

Report date:

1986

Reference 2

Reference Type:

publication

Title:

Unnamed

Year:

1986

Reference 3

Reference Type:

secondary source

Title:

Unnamed

Year:

2001

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

no

Principles of method if other than guideline:

Dynamic study: Groups of 5 male and 5 female Hilltop-Wistar albino rats were exposed for four hours to dynamically generated vapour of 2,4-pentanedione. Concentrations tested were 628, 919, 1231 and 1508 ppm (corresponding to 2619, 3823, 5133 and 6288 mg/m3). Chamber concentrations were concurrently analysed throughout each 4-hour exposure by GC. Postexposure period 14 d, body weight determined at 0, 7 and 14 d postexposure.

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Details on test material:

Purity: 99%

Test animals

Species:

rat

Strain:

other: Hilltop-Wistar albino rats [HLA(WI)BR]

Sex:

male/female

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

not specified

Vehicle:

not specified

Details on inhalation exposure:

Chamber concentrations concurrently analysed throughout each 4-hour exposure by GC.

Analytical verification of test atmosphere concentrations:

not specified

Duration of exposure:

4 h

Concentrations:

628, 919, 1231 and 1508 ppm (corresponding to 2619, 3823, 5133 and 6288 mg/m3)

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: Body weight was determined 0, 7, and 14 days postexposure.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight, organ weights, histopathology

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

5 104 mg/m³ air (analytical)

Based on:

test mat.

95% CL:

>= 4 432 - <= 5 876

Exp. duration:

4 h

Mortality:

Dynamic exposure: The results indicate that the 4 hour dynamic LC50 (95 % confidence limits) for 2,4-pentanedione (combined male and female) is 1224 (1063 to 1409) ppm (corresponding to 5104 (4432 - 5876) mg/m3). The LC50 was determined for combined male and female rat. Deaths were observed with both male and female rats exposed to concentrations of 1508 and 1231 ppm (mortality 8/10 and 6/10). Deaths occurred mostly during exposure or within 24 hours post-exposure (1 exception on day 3 in male rats in the 1508 ppm group). No mortalities were observed with rats exposed to dynamic concentrations of 919 or 628 ppm.

Clinical signs:

other: Clinical signs observed in rats of the 1508 and 1231 ppm exposure groups included periocular, perinasal and perioral wetness and encrustation, forced respiration, distended abdomen, tremors, ataxia, decreased motor activity, a negative tail and toe pinch

Gross pathology:

Necropsy of rats that died: red lungs, dark livers, gas-filled stomachs. No effects on sacrificed survivors.

Applicant's summary and conclusion

Interpretation of results:

Category 3 based on GHS criteria

Conclusions:

Under the evaluated conditions, an LC50 value of 5104 mg/m³ was determined (male/female combined).

Executive summary:

The results indicate that the 4 hour dynamic LC50 (95 % confidence limits) for 2,4-pentanedione (combined male and female) is 1224 (1063 to 1409) ppm (corresponding to 5104 (4432 - 5876) mg/m3). The LC50 was determined for combined male and female rat. Deaths were observed with both male and female rats exposed to concentrations of 1508 and 1231 ppm (mortality 8/10 and 6/10). Deaths occurred mostly during exposure or within 24 hours post-exposure (1 exception on day 3 in male rats in the 1508 ppm group). No mortalities were observed with rats exposed to dynamic concentrations of 919 or 628 ppm.

Clinical signs observed in rats of the 1508 and 1231 ppm exposure groups included periocular, perinasal and perioral wetness and encrustation, forced respiration, distended abdomen, tremors, ataxia, decreased motor activity, a negative tail and toe pinch. Deceased animals had red lungs, dark livers and gas-filled stomachs. The surviving animals did not show any abnormalities in necropsy.