Disodium 4-[4-[[5-[(2-bromo-1-oxoallyl)amino]-2-sulphonatophenyl]azo]-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl]-2,5-dichlorobenzenesulphonate

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:

1993

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. 4 instead of 5 test concentration. Preparation of he inoculum: Higher sludge weight after the washing procedure (sludge concentrations in the test according to the Guidelines).

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Test substance:
Code number: FAT-40'061/D
EN-number: 280736.26
Purity: 98.3
Appearance: Solid
Solubility: 100 g/l in water
Storage: room temperature
Expiration date: may 1998
Safety: Test substance will, unless otherwise specified, be handled using safety precautions "Sicherheit im Labor von A - Z", SAV: 00 303

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

other: Activated sludge of a communal sewage treatment plant (ARA-Pro Rheno Basel).

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20.2 °C

pH:

pH of sludge: 6.6 before the test beginning.

Dissolved oxygen:

0.1 - 0.2 l/min by pasteur-pipette

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 (Merck 821768)

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

Remarks:

respiration rate

Details on results:

The IC50 (3 h) of the test substance FAT 40061/D : >320.0 mg/l.

Results with reference substance (positive control):

The IC50 (3 h) of the reference substance 3,5-Dichlorophenol : 7.8 mg/l.

Validity criteria fulfilled:

yes

Conclusions:

The IC50 (3 h) of the test substance FAT 40061/D: >320.0 mg/l.

Executive summary:

The objective of this study was the determination of the test substance concentration, which reduces the respiration of activated sludge by 50 % (IC50 value). The toxicity of FAT 40061/D to activated sludge was determined in a 3-hour respiration inhibition test according to the OECD Guideline No. 209, and to the EG Method Nr.L 133/118. The test was performed in compliance with the Good Laboratory Practice (GLP) Regulations of Switzerland. The test substance concentrations tested were 320,100, 32 and 10 mg/l and the % inhibitions obtained were 0, 0, 0 and 4.44 % respectively. Based on these findings, IC50 (3 h) of the test substance FAT 40061/D was determined to be >320.0 mg/l.

Description of key information

The objective of this study was the determination of the test substance concentration, which reduces the respiration of activated sludge by 50 % (IC50 value). The toxicity of FAT 40061/D to activated sludge was determined in a 3 hours respiration inhibition test according to the OECD Guideline No. 209, and to the EG Method Nr.L 133/118. The test was performed in compliance with the Good Laboratory Practice (GLP) Regulations of Switzerland. The test substance concentrations tested were 320,100, 32 and 10 mg/l and the % inhibitions obtained were 0, 0, 0 and 4.44 % respectively. Based on these findings,IC50 (3 h) of the test substance FAT 40061/D was determined to be >320.0 mg/l. In the other supporting study, the IC50 value for FAT 40061/A was found to be greater than 300 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:

320 mg/L