Sodium 3-[[3-methoxy-4-[(4-methoxyphenyl)azo]phenyl]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:

Experiment start and end date - 16 October 1990; Study completion date - 11 December 1990.

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:

no

Qualifier:

according to guideline

Guideline:

ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: ETAD-Method No.103

GLP compliance:

yes

Specific details on test material used for the study:

Test substance: FAT 20004/H
Storage: room temperature
Appearance: Solid
Purity: 100 %

Analytical monitoring:

no

Vehicle:

not specified

Test organisms (species):

activated sludge

Details on inoculum:

mixed culture of bacteria (sludge of a Husman apparatus)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

19.5 °C

Nominal and measured concentrations:

1, 3.2, 10, 32, 56 and 100 mg/L

Details on test conditions:

O2 consumption, measured with an oxygen-sensitive electrode system: OXI DIGI 530.

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Results with reference substance (positive control):

The IC50 of the reference substance 3,5-Dichlorophenol is: 18 mg/l (Criteria: 10 - 25 mg/l)

Validity criteria fulfilled:

yes

Conclusions:

The IC50 (3 h) of the test substance FAT 20004/H was found to be greater than 100 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 20004/H 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 1, 3.2, 10, 32, 56 and 100mg/l. The reference substance used was 3, 5-Dichlorophenol in concentrations of 32, 10 and 3.2 mg/l.

Results:

IC50 (3 h) of the test substance FAT 20004/H: >100.0 mg/l

IC50 (3 h) of the reference substance 3, 5-Dichlorophenol: 18 mg/l

Description of key information

The IC50 of FAT 20004 was found to be >100 mg/l.

Key value for chemical safety assessment

EC50 for microorganisms:

100 mg/L

Additional information

In a key study carried out to determine IC50 of FAT 20004/H according to GLP guideline 209, the IC50 value for FAT 20004 was found to be greater than 100 mg/L. Several other supporting studies were also performed and the IC50 value for FAT 20004 was found to be greater than 300 & 200 mg/L.