Reaction mass of Disodium [3-{[4-chloro-2-(hydroxy-kO)-5-methoxyphenyl]diazenyl-kN2}-4-(hydroxy-kO)naphthalene-2,7-disulfonato(4-)](hydroxy)chromate(2-) and Trisodium [3-{[4-chloro-2-(hydroxy-kO)-5-methoxyphenyl]diazenyl-kN2}-4-(hydroxy-kO)naphthalene-2,7-disulfonato(4-)](dihydroxy)chromate(3-)

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22 June 1994 to 26 July 1994

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

yes

Remarks:

higher sludge weight after the washing procedure (Sludge concentrations in the test according to the guidelines). 4 instead of 5 test concentrations.

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Code number: FAT 20044/B
Batch-Nr.: 99
Appearance: solid
Solubility: 60g/l [in water]
Storage: room temperature
Expiration date: 07/99

Analytical monitoring:

not specified

Vehicle:

yes

Remarks:

deionized water

Details on test solutions:

Stock solutions 500 mg/l test substance / reference substance in deionized water.
Test concentrations: 320, 100, 32 and 10 mg/l of the test substance.
32, 10 and 3.2 mg/l of the reference substance.

Test organisms (species):

activated sludge, domestic

Details on inoculum:

Sludge pretreatment: 3 times washing with tap water and addition of synthetic sewage (a day before the main test).

Test type:

not specified

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Test temperature:

21.5 °C

pH:

7.6

Nominal and measured concentrations:

Test concentrations: 320, 100, 32 and 10 mg/l of the test substance. 32, 10 and 3.2 mg/l of the reference substance.

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 320 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Results with reference substance (positive control):

The IC50 (3 h) of the reference substance 3,5-Dichlorophenol 15.0 mg/l.

Validity criteria fulfilled:

not specified

Conclusions:

The IC50 (3 h) of FAT 20044/B >320.0 mg/l.

Executive summary:

Determination of the IC50 (3 h) (Activated sludge respiration inhibition test) with FAT 20044/B was carried out according to OECD guideline 209. Test concentrations used was 320, 100, 32 and 10 mg/l of the test substance and 32, 10 and 3.2 mg/l of the reference substance. Based on the study results, the IC50 (3 h) of FAT 20044/B >320.0 mg/l while that of the reference substance 3,5-Dichlorophenol 15.0 mg/l.

Description of key information

Determination of the IC50 (3 h) (Activated sludge respiration inhibition test) with FAT 20044/B was carried out according to OECD guideline 209. Test concentrations used was 320, 100, 32 and 10 mg/l of the test substance and 32, 10 and 3.2 mg/l of the reference substance. Based on the study results, the IC50 (3 h) of FAT 20044/B is >320.0 mg/l while that of the reference substance 3,5-Dichlorophenol is 15.0 mg/l.

Key value for chemical safety assessment

EC50 for microorganisms:

320 mg/L