Disodium 1,1'-isopropylidenedi-p-phenylene bis[2-[[5-amino-3-methyl-1-(3-sulphonatophenyl)-1H-pyrazol-5-yl]azo]benzenesulphonate]

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:

9 March to 10 March 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:

- Deion. water instead of dest. water for the stock solution. - Preparation of the inoculum : 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)

Remarks:

Swiss GLP

Specific details on test material used for the study:

- Batch no: 1
- Purity: 80 %
- Storage: Room temperature
- Expiry date: 10/98

Analytical monitoring:

yes

Vehicle:

yes

Details on test solutions:

None

Test organisms (species):

activated sludge, domestic

Details on inoculum:

Organisms: Activated sludge of a communal sewage treatment plant (ARA-Birsig Therwil)
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:

no

Total exposure duration:

3 h

Remarks on exposure duration:

None

Post exposure observation period:

None

Hardness:

None

Test temperature:

Temperature: 21.5 °C

pH:

pH of sludge: 7.8 at the beginning of the test

Dissolved oxygen:

None

Salinity:

None

Conductivity:

None

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

Details on test conditions:

Test system / Test organism:
Organism: Activated sludge of a communal sewage treatment plant (ARA-Birsig Therwil)
Sludge pretreatment: 3 times washing with tap water and addition of synthetic sewage (a day before the main test)

Experimental conditions:
Temperature: 21.5 °C
Sludge dry weight: 1.56 g/l
Test volume: 100 ml
Test duration: 3h
Estimation technique: O2 - consumption, measured with an oxygen sensitive electrode system: OXI DIGI 530 (SAV : 00 109)
Aeration: 0.1 - 0.2 l/min by pasteur-pipette
pH of sludge: 7.8 before the test beginning

Reference substance (positive control):

yes

Key result

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 320 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Details on results:

The IC50 (3 h) of the test substance FAT - 21'015/B was >320.0 mg/l
The IC20 (3 h) of the test substance FAT - 21'015/B was 165.0 mg/l

Results with reference substance (positive control):

The IC50 (3 h) of the reference substance 3,5-Dichlorophenol: 9.5 mg/l

Reported statistics and error estimates:

None

Validity criteria fulfilled:

yes

Conclusions:

The IC50 (3h) for FAT 21015/B was found to be greater than 320 mg/L.

Executive summary:

The toxicity of FAT 21015/B to activated sludge was determined in a 3-h respiration inhibition test according to the EEC Method No. L 133/118 -122 and to the OECD Guideline No. 209. The test substance concentrations tested were 320,100, 32 and 10 mg/l. The reference substance, 3,5-Dichlorophenol was tested in concentrations of 32, 10 and 3.2 mg/l. The IC₅₀ (3h) for FAT 21015/B was found to be greater than 320 mg/L while that of reference substance 3,5-Dichlorophenol was 9.5 mg/l.

Description of key information

The toxicity of FAT 21015/B to activated sludge was determined in a 3-h respiration inhibition test according to the EEC Method No. L 133/118 -122 and to the OECD Guideline No. 209. The test substance concentrations tested were 320,100, 32 and 10 mg/l. The reference substance, 3,5-Dichlorophenol was tested in concentrations of 32, 10 and 3.2 mg/l. The IC₅₀(3h) for FAT 21015/B was found to be greater than 320 mg/L while that of reference substance 3,5-Dichlorophenol was 9.5 mg/l. In another supporting study, the IC50 value for FAT 21015/A was found to be greater than 300 mg/l.

Key value for chemical safety assessment

EC50 for microorganisms:

320 mg/L