Disodium 5,5'-[(1-methylethylidene)bis(4,1-phenyleneoxysulphonyl-2,1-phenyleneazo)]bis[6-amino-4-hydroxynaphthalene-2-sulphonate]

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:

Study initiation date - 15 March 1995; Experimental start and end date - 22 March 1995; Study completion date - 27 March 1995.

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:

See "Any other information on materials and methods incl. tables"

Qualifier:

according to guideline

Guideline:

other: EEC Directive 87/302, L 133/118- 122 "Activated Sludge, Respiration Inhibition Test", (Edition : 30.05.1988).

Deviations:

yes

Remarks:

See "Any other information on materials and methods incl. tables"

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Code number: FAT 21021/D
Batch-No.: 9
Purity: ca. 70 %
Appearance: solid
Solubility: 30 g/l
Storage: room temperature
Expiration: 12/99

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge

Details on inoculum:

Organism: Activated sludge of a communal sewage treatment plant (ARA-Pro Rheno Basel).
Sludge pretreatment: 3 times washing with tap water and addition of synthetic sewage (a day before the main test).

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20 ± 2 °C

pH:

7.8

Nominal and measured concentrations:

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.

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 respiration due to nitrification

Results with reference substance (positive control):

IC50 (3h) of 3.5-Dichlorophenol was determined to be 13 mg/L.

Validity criteria fulfilled:

not specified

Conclusions:

IC50 (3 h) of the test substance FAT 21021/D was found to be greater than 320 mg/L.

Executive summary:

The toxicity of FAT 21021/D to activated sludge was determined in a 3-hours respiration inhibition test according to the EEC Directive 87/302, L 133/118- 122 and to the OECD Guideline No. 209. This study was performed in compliance with Good Laboratory Practice (GLP) and based on the OECD Principles of Good Laboratory Practice, adopted May 12, 1981. The test substance concentrations tested were 320, 100, 32 and 10 mg/L. The reference substance used was 3,5-Dichlorophenol. Based on the findings of the study, the IC50 of FAT 21021/D was found to be greater than >320 mg/L. The IC50 (3h) of 3.5-Dichlorophenol was determined to be 13 mg/L.

Description of key information

In a key study the toxicity of FAT 21021/D to activated sludge was determined in a 3-hours respiration inhibition test according to the EEC Directive 87/302, L 133/118- 122 and to the OECD Guideline No. 209. This study was performed in compliance with Good Laboratory Practice (GLP) and based on the OECD Principles of Good Laboratory Practice, adopted May 12, 1981. The test substance concentrations tested were 320, 100, 32 and 10 mg/L. The reference substance used was 3,5-Dichlorophenol. Based on the findings of the study, the IC50 of FAT 21021/D was found to be greater than >320 mg/3. IC50 (3h) of 3.5-Dichlorophenol was determined to be 13 mg/L. This outcome was further supported by the results of a similar study with FAT 21021/A, where the IC50 was found to be greater than 300 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:

320 mg/L