lambda4-cerium(4+) zirconium(4+) tetraoxidandiide

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Study period:

November - December 1982

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to OECD TG 403-compliant study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1983

Report date:

1983

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

no

GLP compliance:

no

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Cerium dioxide

EC Number:

215-150-4

EC Name:

Cerium dioxide

Cas Number:

1306-38-3

Molecular formula:

CeO2

IUPAC Name:

cerium dioxide

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: not specified
- Age at study initiation: not specified
- Weight at study initiation: 180 - 186 g
- Fasting period before study: no
- Housing: by groups of 5 in makrolon cages
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 3
- Humidity (%): 50 +/- 20
- Air changes (per hr): 12
- Photoperiod (hrs dark / hrs light): 12 / 12


IN-LIFE DATES: Exact dates not specified

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
- Exposure apparatus: disposable air-tight chamber, particle generator, exposure cages, densitometer, regulator, dust measurer and granulometer
- Exposure chamber volume: 1 m3
- Method of holding animals in test chamber: stainless steel wired cages (35 x 24 x 20 cm) of 5 animals per sex
- Source and rate of air / Method of conditioning air: not specified
- System of generating particulates/aerosols: micronizer with non-powdery, compressed air supplied with test powder through a vibrating tunnel
- Method of particle size determination: granulometer (0.5 µ to 10 µ)
- Treatment of exhaust air: not specified
- Temperature, humidity, pressure in air chamber: 21-22°C, 27-40%, not specified, respectively


TEST ATMOSPHERE
- Brief description of analytical method used: aerosol concentration measured by light relection / mass concentration of dust inside the chamber measured by differential measurement of beta-rays transmission
- Samples taken from breathing zone: yes
- Particle size distribution:
0.5 to 1 µ = 98.3%
1 to 3 µ = 1.7%
- MGMD (Mean Gravimetric Median Diameter): 0.754 µ

- Rationale for the selection of the starting concentration: described as 'maximum technological concentration'

Analytical verification of test atmosphere concentrations:

yes

Remarks:

aerosol concentration measured by light reflection

Duration of exposure:

4 h

Concentrations:

Mean observed concentration = 2.01 mg/L

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:
Mortality and clinical signs: during exposure, for the following hours, and daily during 14 days
Body weight: just after exposure and on days 1, 2, 4, 7 and 14
- Necropsy of survivors performed: yes
- Other examinations performed: histopathology on macroscopic abnormalities

Statistics:

Not included

Results and discussion

Effect levels

Effect levels 1

Sex:

male/female

Dose descriptor:

LC0

Effect level:

2.01 mg/L air (analytical)

Based on:

act. ingr.

Exp. duration:

4 h

Remarks on result:

other: Maximum technically administrable concentration

Effect levels 2

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 2.01 mg/L air (analytical)

Based on:

act. ingr.

Exp. duration:

4 h

Remarks on result:

other: Maximum technically administrable concentration

Mortality:

No mortality occurred during the observation period

Clinical signs:

other: No clinical signs were observed

Body weight:

No significant body weight changes occured

Gross pathology:

At necropsy, no macroscopic abnormalities were observed

Applicant's summary and conclusion

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: other: Annex VI Directive 67/548/EEC or UN/EU GHS

Conclusions:

Inhalation LC50 higher than 2.01 mg/L for male and female rats exposed for 4 hours

Executive summary:

In an acute inhalation toxicity study (Institut Français de Toxicologie report No. 302217 E), one group of Sprague-Dawley rats (5/sex) was exposed by whole-body inhalation route to Cerium Oxide for 4 hours at a mean concentration of 2.01mg/L, the maximum technically administrable concentration, and observed for 14 days. Mortality and clinical signs were checked during and within the few hours after exposure, and daily for 14 days. Body weight was recorded prior to exposure and on days 1, 2, 4, 7 and 14.

 

No mortality occurred during the observation period. No clinical signs were observed. No significant body weight changes occurred. At necropsy, no macroscopic abnormalities were observed.

 

Therefore, the inhalation LC50 was higher than 2.01 mg/L for males and females exposed for 4 hours. No classification for acute inhalation toxicity is warranted based on the absence of mortality at the concentration tested, according to the criteria of Annex VI Directive 67/548/EEC or UN/EU GHS.

 

This study is classified as acceptable. Its design is compatible with the OECD 403 guideline requirements for acute inhalation toxicity.