A mixture of: sodium/potassium 7-[[[3-[[4-((2-hydroxy-naphthyl)azo)phenyl]azo]phenyl]sulfonyl]amino]-naphthalene-1,3-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:

17 July 1992 to 14 October 1992

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

yes

Remarks:

Deion. water instead of dest. water for the stocksolution; 4 instead of 5 test concentrations; test temperature was 22.6 °C instead of 20 ± 2 °C

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Code number: FAT45155/B
Batch number: TV1
Appearance: solid
Solubility: ~100g/l (in water) [estimation]
Storage: room temperature + light protected
Expiration date: 15.5.1997

Analytical monitoring:

no

Details on sampling:

no data

Vehicle:

no

Details on test solutions:

Test concentrations: 320, 100, 32 and 10 mg/l of the test substance; 32, 10 and 3.2 mg/l of the reference substance

Test organisms (species):

activated sludge

Details on inoculum:

organism: activated sludge of a communal sewage treatment plant (ARA-Pro Pheno Basel)
sludge pretreatment: 3 times washing with tap water and addition of synthenic sewage (a day before the main test)
pH of sludge: 6.6 before the start of the experiment

Test type:

static

Water media type:

not specified

Limit test:

no

Total exposure duration:

3 h

Hardness:

no data

Test temperature:

Temperature: 22.6 °C

pH:

7.3-7.7

Dissolved oxygen:

not applicable

Salinity:

no data

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

Details on test conditions:

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

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

Results with reference substance (positive control):

The IC50 of the reference substance 3,5-Dichlorophenol : 10.5 mg/l.

Reported statistics and error estimates:

IC50: The respiration rate of each test concentration was calculated as a percentage of the mean of the two control respiration rates. The results were plotted on a logarithmic (concentration)/normal (% inhibition) graph.

Validity criteria fulfilled:

yes

Conclusions:

The IC50 (3 h) of FAT 45155/B is > 320 mg/l.

Executive summary:

A GLP-compliant toxicity study of FAT 45'155/B to activated sludge was determined in a 3-h respiration inhibition test according to the OECD Guideline No. 209. The test substance concentrations tested were 320,100, 32 and 10 mg/l. The reference substance 3,5-Dichlorophenol was tested in concentrations of 32,10 and 3.2 mg/l. Based on the study results, IC50 of FAT-45155/B is >320 mg/l while the reference substance is 10.5 mg/l.

Description of key information

The IC50 of test substance is >320 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:

320 mg/L

Additional information

A GLP-compliant toxicity study of FAT 45155/B to activated sludge was determined in a 3-h respiration inhibition test according to the OECD Guideline No. 209. The test substance concentrations tested were 320,100, 32 and 10 mg/l. The reference substance 3,5-Dichlorophenol was tested in concentrations of 32,10 and 3.2 mg/l. Based on the study results, IC50 of FAT 45155/B is >320 mg/l while the reference substance is 10.5 mg/l.