Phosphoric acid, chromium(3+) salt (1:2.5)

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

other: read-across from constituent CrIII

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

publication

Title:

Effects of organic and inorganic substances on the cell proliferation of L- 929 fibroblasts and Tetrahymena pyriformis GL protozoa used for toxicological bioassays

Author:

Sauvant MP, Pepin D, Groliere CA, Bohatier J

Year:

1995

Bibliographic source:

Bulletin of Environmental Contamination and Toxicology 55: 171–178

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

Exponentially growing cultures of Tetrahymena pyriformis were exposed to the test substance for a total of 9 hours.
Population density was determined every hour by sub-sampling and cell counting via Coulter Counter.
The population growth in each treatment was evaluated in terms of doubling times (DT) relative to the control.
A 50% inhibitory concentration (IC50), for doubling time relative to the control was then determined by regression analysis.

GLP compliance:

not specified

Test material

Test material information

1

Reference substance name:

Cr III

Molecular formula:

Cr III

IUPAC Name:

Cr III

Details on test material:

CrCl3.6H2O or CrCl3

Sampling and analysis

Analytical monitoring:

not specified

Details on sampling:

not reported

Test solutions

Vehicle:

not specified

Details on test solutions:

Stock solutions of the test substance were prepared in deionized water. Further dilutions were made in deionized water. A five-step graded concentration series was used.

Test organisms

Test organisms (species):

Tetrahymena pyriformis

Details on inoculum:

- Laboratory culture: The protozoa (Strain BGL) were grown axenically at 28ºC in the PPYS-defined medium (proteose peptone yeast-extract substrate) containing protose peptone (Difco), yeast extracts (Difco), and inorganic salts. The cells were maintained in exponential growth phase.

- Initial biomass concentration: 10000 cells/ml

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

9 h

Remarks on exposure duration:

3, 6 and 9 h

Post exposure observation period:

9 h

Test conditions

Hardness:

not reported

Test temperature:

28 °C

pH:

not reported

Dissolved oxygen:

not reported

Salinity:

not reported

Conductivity:

not reported

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

62 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Basis for effect:

growth inhibition

Effect concentrations 2

Duration:

6 h

Dose descriptor:

IC50

Effect conc.:

54 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Basis for effect:

growth inhibition

Effect concentrations 3

Duration:

9 h

Dose descriptor:

IC50

Effect conc.:

50 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Basis for effect:

growth inhibition

Results with reference substance (positive control):

no data

Reported statistics and error estimates:

IC50 calculated with the linear regression model.

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Conclusions:

The 3h-IC50 of chromium chloride to Tetrahymena pyriformis was 62 mg Cr/L under test conditions. For a test duration of 9 h, an IC50 of 50 mg/L has been obtained; equivalent to 152.3 mg/L CrCl3.