Reaction mass of lithium sodium hydrogen 4-amino-6-({5-[(5-chloro-2,6-difluoropyrimidin-4-yl)amino]-2-sulfonatophenyl}diazenyl)-5-hydroxy-3-[(4-{[2-(sulfonatooxy)ethyl]sulfonyl}phenyl)diazenyl]naphthalene-2,7-disulfonate and lithium sodium hydrogen 4-amino-6-({5-[(5-chloro-2,6-difluoropyrimidin-4-yl)amino]-2-sulfonatophenyl}diazenyl)-5-hydroxy-3-{[4-(vinylsulfonyl)phenyl]diazenyl}naphthalene-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:

05-03-2001 to 06-03-2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

The test substance was added to 130 mL of deionised water and stirred overnight before testing.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Name and location of sewage treatment plant where inoculum was collected: aeration tank of a wastewater treatment plant treating predominantly domestic sewage (Wupper area water authority)
- Pretreatment: aeration of the activated sludge and daily feed with synthetic medium

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

18-22°C

pH:

6.9

Nominal and measured concentrations:

Nominal: 100, 1000 and 10000 mg/L

Details on test conditions:

TEST SYSTEM
- Sludge concentration (weight of dry solids per volume): 400 mg/L
- Nutrients provided for bacteria: synthetic medium

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionised water

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : oxygen consumption of the activated sludge exposed to the test substance concentrations

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 10

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol at 5, 10 and 20 mg/L

Key result

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

> 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

The test substance caused only 8% respiration inhibition of the activated sludge microorganisms.

All validity criteria of the study were met and the study was considered acceptable.

Results with reference substance (positive control):

The EC50 of the reference substance was determined to be 11 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

Under the study conditions, the nominal 3 h EC10 and EC50 of the test substance were >10000 mg/L.

Executive summary:

A study was conducted to determine the toxicity of the test substance to wastewater sludge bacteria according to OECD Guideline 209 and EU Method C.11, in compliance with GLP. The activated sludge at the equivalent of 400 mg/L was exposed to nominal concentrations of 0, 100, 1000 and 10000 mg/L of the test substance for 3 h. The positive control or reference substance 3,5 -dichlorophenol was run in parallel at 5, 10 and 20 mg/L. Temperature, pH and oxygen inhibition were recorded at test start and end. The test substance caused only 8% respiration inhibition of the sludge bacteria. Under the study conditions, the nominal 3 h EC10 and EC50 of the test substance were >10000 mg/L (Müller, 2001).

Description of key information

The nominal 3 h EC10 and EC50 of the test substance were >10000 mg/L

Additional information

A study was conducted to determine the toxicity of the test substance to wastewater sludge bacteria according to OECD Guideline 209 and EU Method C.11, in compliance with GLP. The activated sludge at the equivalent of 400 mg/L was exposed to nominal concentrations of 0, 100, 1000 and 10000 mg/Lof the test substance for 3 h. The positive control or reference substance 3,5 -dichlorophenol was run in parallel at 5, 10 and 20 mg/L. Temperature, pH and oxygen inhibition were recorded at test start and end. The test substance caused only 8% respiration inhibition of the sludge bacteria at the highest concentration of 10000 mg/L. Under the study conditions, the nominal 3 h EC10 and EC50 of the test substance were >10000 mg/L (Müller, 2001).