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Toxicological information

Acute Toxicity: inhalation

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Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Proprietary, GLP-compliant guideline-equivalent study.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1985

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Deviations:
no
GLP compliance:
yes
Test type:
standard acute method
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
The test material consisted of orange granules and was prepared as a mixture from four different sources

Test animals

Species:
rat
Strain:
Fischer 344
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River USA
- Age at study initiation: Young adult
- Weight at study initiation: 80-100 g
- Fasting period before study: -
- Housing: Individual
- Diet: ad libitum except during exposure
- Water: ad libitum except during exposure
- Acclimation period: two weeks


ENVIRONMENTAL CONDITIONS
- Temperature (°C): not reported
- Humidity (%): not reported
- Air changes (per hr): not reported
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
whole body
Vehicle:
other: water
Details on inhalation exposure:
Liquid aerosols of the test material were generated using a nebuliser. Animals were exposed in a chamber of 225 l volume, with an airflow of at least 43 l/min.
Analytical verification of test atmosphere concentrations:
yes
Remarks:
colorimetric
Duration of exposure:
4 h
Concentrations:
50, 60, 100 or 160 mg/m3
No. of animals per sex per dose:
Five
Control animals:
yes
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations: animals were observed every 15 minutes during the first two hours of exposure, then hour;y and twice daily thereafter
- Necropsy of survivors performed: yes
- Other examinations performed: bodyweights were recorded on Days 1, 2, 3, 4, 7, 10 and 14; organ weights recorded at necropsy
Statistics:
Analysis of variance and multiplce comparison parameters for continous parametric data; Fisher's exact test and Wilcoxon Rank Sum test for discontinous data. LC50 values according to Litchfield & Wilcoxon.

Results and discussion

Preliminary study:
Not applicable
Effect levelsopen allclose all
Sex:
male
Dose descriptor:
LC50
Effect level:
99 mg/m³ air (analytical)
Exp. duration:
4 h
Sex:
female
Dose descriptor:
LC50
Effect level:
83 mg/m³ air (analytical)
Exp. duration:
4 h
Sex:
male/female
Dose descriptor:
LC50
Effect level:
94 mg/m³ air (analytical)
95% CL:
78 - 109
Exp. duration:
4 h
Mortality:
Mortality was seen in males at >=60 mg/m3 and at >=100 mg/m3 in females. Deaths occurred between Days 3-10.
Clinical signs:
No signs of toxicity were observed during the exposure period. Signs of toxicity were observed post exposure at 50 mg/m3 (rapid breathing, rales, red nasal discharge), 60 mg/m3 (additionally rough coat), 100 mg/m3 (additionally thin appearance, gasping, hypoactivity, yellow fur, dyspnoea) and 160 mg/m3 (additionally laboured breathing and hypothermia).
Body weight:
Weight losses were seen in surviving animals at 60, 100 and 160 mg/m3, initially reduced weight gain was seen at 50 mg/m3.
Gross pathology:
Gross necropsy revealed discolored lungs in all treated groups.
Other findings:
Lung weights were increased in exposed animals compared to controls.

Any other information on results incl. tables

Concentration (mg/m3)

Mean particle size (µm)

Mortality

Nominal

Analytical

M

F

0

-

-

0/5

0/5

180

50

1.4

0/5

0/5

330

60

*

1/5

0/5

520

100

1.5

4/5

5/5

500

160

*

5/5

5/5

*not analysed

Particle size was not analysed in two of the exposure groups due to technical problems, however results from other groups indicate a sufficiently small particle size.

Applicant's summary and conclusion

Interpretation of results:
very toxic
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The acute inhalation LC50 values of 83-99 mg/m3 (0.088-0.093 mg/l) result in classification of potassium dichromate as (R26) 'Very toxic by inhalation'
Executive summary:

The acute inhalation toxicity of potassium dichromate in the rat was investigated in a guideline-comparable study. Groups of rats (5/sex) were exposed to aerosols of the test substance (in water) at achieved concentrations of 0, 50, 60, 100 or 160 mg/m3 and observed for 14 days. Signs of toxicity were observed in all exposed groups; deaths occurred in males at >=60 mg/m3 and in females at >=100 mg/m3. Reduved weight gain or weight loss was seen in survivng animals. Gross necropsy revealed discoloration of the lungs in all treated groups; lung weights were also elevated.

LC50 values of 83 -99 mg/m3 were calculated.