trisodium 3-amino-4-[4-[4-(2-(2-ethenylsulfonylethoxy)ethylamino)-6-fluoro-1,3,5-triazine-2-ylamino]-2-sulfophenylazo]-5-hydroxynaphthalene-2,7-disulfonate

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 - 18 February 1999; Experiment start date - 24 February 1999; Experiment completion date - 03 March 1999; Study completion date - 24 March 1999.

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

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Identity: FAT 40'574/B
Batch: WP 23/99
Purity: Approx. 75 %
Appearance: Solid, dark-red powder
Storage: At room temperature at about 20 °C
Expiration Date: 08 February 2006

Analytical monitoring:

no

Vehicle:

yes

Details on test solutions:

1.0 g/500 ml of the test substance in deionized water. 500 mg/l of the reference substance in deionized water.

Test organisms (species):

activated sludge, industrial

Details on inoculum:

Test system: Activated sludge of a communal sewage treatment plant (ARA-Pro Rheno Basel) collected on February 23, 1999

Sludge pre-treatment: The inoculum was prepared 1 day prior to the experimental start. The freshly collected activated sludge was washed 3 times with tap water. Subsequently the sludge was aerated. A sample of the activated sludge was taken to determine the dry weight of the suspended solids. The final concentration of the inoculum was adjusted to about 5.0 g/l suspended solids. For the storage over night synthetic sewage feed was added depending on the sludge concentration.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

21.0 - 21.2 °C

pH:

8.2 - 8.5

Dissolved oxygen:

7.4 - 10.0

Nominal and measured concentrations:

Nominal: 25.6, 64, 160, 400 and 1000 mg/l of the test substance.
3.2, 10 and 32 mg/l of the reference substance.

Details on test conditions:

Sludge dry weight: 1.56 g/l suspended solids
Test volume: 100 ml
Test duration: 3 h
Aeration: 0.1 - 0.2 l/min by Pasteur pipette
Estimation technique: O2 - consumption, measured with an oxygen sensitive electrode system: OXI DIGI 530 (SOP: 00 109)

Reference substance (positive control):

yes

Remarks:

3,5 - Dichlorophenol

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 1 000 mg/L

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

1 000 mg/L

Results with reference substance (positive control):

IC50 (3 h) of the reference substance 3,5-Dichlorophenol: 15 mg/l.

Validity criteria fulfilled:

yes

Conclusions:

An IC50 value for the test substance was found to be greater than 1000 mg/L.

Executive summary:

The objective of this study was the determination of the test substance concentration, which reduces the respiration activity of activated sludge by 50 % (IC50 value). This study was conducted according to OECD test guideline 209 in a GLP-certified laboratory. Activated sludge of a communal sewage treatment plant (ARA-Pro Rheno Basel) was inoculum used for this study. 3,5 -Dichlorphenol served as positive control. The test substance concentration was 25.6, 64, 160, 400 and 1000 mg/l. The respiration rate of an activated sludge fed with a standard amount of synthetic sewage feed was measured after a contact time of 3 hours. Based on the findings of this study, the IC50 value for the test substance was found to be greater than 1000 mg/L.

Description of key information

The IC50 value for the test substance was found to be greater than 1000 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:

1 000 mg/L

EC10 or NOEC for microorganisms:

1 000 mg/L

Additional information

The objective of this study was the determination of the test substance concentration, which reduces the respiration activity of activated sludge by 50 % (IC50 value). This study was conducted according to OECD test guideline 209 in a GLP-certified laboratory. Activated sludge of a communal sewage treatment plant (ARA-Pro Rheno Basel) was inoculum used for this study. 3,5 -Dichlorphenol served as positive control. The test substance concentration was 25.6, 64, 160, 400 and 1000 mg/l. The respiration rate of an activated sludge fed with a standard amount of synthetic sewage feed was measured after a contact time of 3 hours. Based on the findings of this study, the IC50 value for the test substance was found to be greater than 1000 mg/L.