Dichromium tris(chromate)

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:

weight of evidence

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: The EU RAR summarises the results of a number of acute inhalation toxicity studies performed with water soluble Cr (VI) compounds; most studies were not performed to recognised guidelines.

Data source

Reference

Reference Type:

review article or handbook

Title:

European Union Risk Assessment Report: chromium trioxide, sodium chromate, sodium dichromate, ammonium dichromate, potassium dichromate

Author:

European Chemicals Bureau

Year:

2005

Bibliographic source:

3rd Priority List; Volume 53

Materials and methods

Principles of method if other than guideline:

The EU RAR reports the results of a number of studies of various designs.

GLP compliance:

not specified

Test type:

other: various

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Chromium trioxide

EC Number:

215-607-8

EC Name:

Chromium trioxide

Cas Number:

1333-82-0

Molecular formula:

CrO3

IUPAC Name:

chromium trioxide

Constituent 2

Reference substance name:

Sodium dichromate

EC Number:

234-190-3

EC Name:

Sodium dichromate

Cas Number:

10588-01-9

Molecular formula:

Cr2H2O7.2Na

IUPAC Name:

sodium dichromate

Constituent 3

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:

Studies were performed with chromium trioxide, sodium dichromate and potassium dichromate.

Test animals

Species:

rat

Strain:

other: various

Sex:

male/female

Administration / exposure

Route of administration:

other: inhalation and intratracheal instillation

Type of inhalation exposure:

not specified

Vehicle:

other: water

Analytical verification of test atmosphere concentrations:

yes

Remarks on duration:

various

Concentrations:

Various

No. of animals per sex per dose:

Various

Control animals:

other: in some studies

Results and discussion

Effect levels

Effect levels 1

Sex:

male

Dose descriptor:

LC50

Effect level:

99 mg/m³ air

Exp. duration:

4 h

Remarks on result:

other: Potassium dichromate

Effect levels 2

Sex:

male

Dose descriptor:

LC50

Effect level:

200 mg/m³ air

Exp. duration:

4 h

Remarks on result:

other: Sodium dichromate

Effect levels 3

Sex:

male

Dose descriptor:

LC50

Effect level:

104 mg/m³ air

Exp. duration:

4 h

Remarks on result:

other: Sodium chromate

Effect levels 4

Sex:

male

Dose descriptor:

LC50

Effect level:

217 mg/m³ air

Exp. duration:

4 h

Remarks on result:

other: Chromium trioxide

Any other information on results incl. tables

The EU RAR states that potassium dichromate aerosols (mass median aerodynamic diameter 1-2 microns) were toxic when inhaled by rats, deaths occurring following a 6-hour exposure to 37 mg/m³ (13 mg Cr (VI)/m³) and above. There were no deaths at 31 mg/m³ (11 mg Cr(VI)/m³). Decreased body weight gain and increased lung weight were observed following 2 -hour exposure to 20 mg/m³ (7 mg Cr(VI)/m³).

LC50 values of 99 mg/m³ (potassium dichromate) (35 mg Cr(VI)/m³), 200 mg/m³ (sodium and potassium dichromate) (70 mg Cr(VI)/m³) and 104 mg/m³ (sodium chromate) (33 mg Cr(VI)/m³) have been reported for male rats with a 4-hour aerosol exposure period. Signs of toxicity included reduced body weight, respiratory distress and irritation of the respiratory tract.

Lung oedema, inflammation and tracheal epithelium necrosis were seen in rats following inhalation of 28 mg/m³ sodium chromate (9 mg Cr(VI)/m³) for 24 hours; minimal lung effects (reduction in glycoprotein secretion in the trachea) were seen at 8 mg/m³ (3 mg Cr(VI)/m³) for 24 hours.

Intratracheal instillation of potassium dichromate at 1.14 mg (0.4 mg Cr(VI)) produced lung inflammation in rats.

An LC50 value of 217 mg/m³ (113 mg Cr(VI)/m³) for chromium (VI) trioxide (presumably aerosol) has been reported for rats with a 4-hour exposure period. It is predicted that severe damage to tissues of the respiratory tract would occur at low concentrations due to the corrosive nature of this substance. In the case of all the Cr (VI) compounds under consideration, depending upon the pH of the Cr (VI) solution, corrosive effects can occur on contact.

Applicant's summary and conclusion

Interpretation of results:

Toxicity Category II

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The available data indicate that the water-soluble Cr (VI) compounds are very acutely toxic by inhalation. Based on the LC50 reported on the soluble Cr (VI) compounds, a theoretical LC50 for Dichromium tris(chromate) should range between 96 and 327 mg active ingredient/m³.

Executive summary:

The EU RAR reports a number of studies designed to investigate the acute inhalation toxicity of water soluble Cr (VI) compounds. The results of these studies indicate that this group of compounds is very toxic by inhalation.