Sodium dichromate

Acute Toxicity: inhalation

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

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

no

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Potassium dichromate

EC Number:

231-906-6

EC Name:

Potassium dichromate

Cas Number:

7778-50-9

Molecular formula:

Cr2H2O7.2K

IUPAC Name:

potassium dichromate

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 or test system 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 levels

Effect levels 1

Sex:

male

Dose descriptor:

LC50

Effect level:

99 mg/m³ air (analytical)

Exp. duration:

4 h

Effect levels 2

Sex:

female

Dose descriptor:

LC50

Effect level:

83 mg/m³ air (analytical)

Exp. duration:

4 h

Effect levels 3

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:

other: 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,

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/m^3)		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.