main component 1 (isomer 1): 2-{6-fluoro-4-[3-(2,5-disulfo-phenylazo)-4-hydroxy-2-sulfonapht-7-ylamino]-1,3,5-triazin-2-ylamino}-3-{6-fluoro-4-[3-(1,5-disulfonaphth-2-ylazo)-4-hydroxy-2-sulfonaphth-7-ylamino]-1,3,5-triazin-2-ylamino}-propane sodium salt;main component 1 (isomer 2): 2-{6-fluoro-4-[3-(2,5-disulfo-phenylazo)-4-hydroxy-2-sulfonaphth-7-ylamino]-1,3,5-triazin-2-ylamino}-3-{6-fluoro-4-[3-(2,5-disulfo-phenylazo)-4-hydroxy-2-sulfonaphth-7-ylamino]-1,3,5-triazin-2-ylamino}-propane sodium salt;main component 2: 2,3-bis-{6-fluoro-4-[3-(2,5-disulfo-phenylazo)-4-hydroxy-2-sulfonaphth-7-ylamino]-1,3,5-triazin-2-ylamino}-propane sodium salt;main component 3: 2,3-bis-{6-fluoro-4-[3-(1,5-disulfonaphth-2-ylazo)-4-hydroxy-2-sulfonaphth-7-ylamino]-1,3,5-triazin-2-ylamino}-propane sodium salt

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:

21 October 1996 to 20 February 1997

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

Qualifier:

according to guideline

Guideline:

other: EEC Directive 87/302, No. L 133/118 "Respiration Inhibition Test"

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Identity: FAT 40557/A
Batch-no.: PV1
Purity: 65 %
Appearance: Solid powder, red-brown
Solubility (g/l): >100
Stability in Water: At least 48 hours
Expiration date: 30 September, 2002
Storage conditions: At room temperature at about 20 °C, away from direct sunlight.

Analytical monitoring:

no

Vehicle:

yes

Details on test solutions:

500 mg test substance was weighted into a 1-L volumetric flask which was filled to volume with bidistilled water. From this stock solution test media were prepared.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Test organisms: Activated sludge of a communal sewage treatment plant (ARA Ergolz II, Füllinsdorf/Switzerland).
- Preparation of sludge: The activated sludge was centrifuged and the supernatant liquid phase decanted. The solid material was resuspended in tap water and again centrifuged. The latter procedure was repeated twice. An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge (g) to its dry weight (g) determined. based on this ration, calculated aliquots od washer sludge suspension, corresponding to 4 g dry material per litre, were made up with Soerensen buffer (pH7). To this mixture, 50 mL OECD recommended synthetic sewage feed per litre was added daily, starting three days prior to use, and the sludge was aerated until use. Before use, the pH was adjusted to 7.8 with 0.5 mol/L H2SO4.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

30 min

Test temperature:

20.5 °C

pH:

7.6-7.9

Nominal and measured concentrations:

Nominal: 0, 3.2, 10, 32, 50 and 100 mg/L.

Details on test conditions:

- The test was carried out in glass flasks (>500 mL) aerated with an air-flow of about 0.2L/minute instead of 0.5L/minute to prevent possible foam development.
- After 30 minutes of aeration at 20.5 °C, the first sample was taken for oxygen measurement over a period of up to 10 minutes. thereafter, in 10-minute intervals the rest of the samples was submitted to measurement of oxygen concentrations. During measurement, the sample was not aerated but continuously stirred on a magnetic stirrer. The apparatus used for oxygen measurements was the WTW OXI 539 meter (Wissenschaftlich-Technische Werkstätten, Weilheim/Germany)

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

The respiration rate od aerobic waste water bacteria was practically not inhibited (-6.6 to 1.7%) when exposed to the test article concentrations in the range from 3.2 to 100 mg/L

Results with reference substance (positive control):

The EC50 (30 minutes) of the reference substance 3,5-Dichlorophenol: 10.4 mg/L

Validity criteria fulfilled:

yes

Conclusions:

The EC50 of FAT 40557/A is > 100 mg/L in microorganisms of activated sludge.

Executive summary:

The toxicity of FAT 40557/A in activated sludge was determined in a GLP-compliant 30 minutes respiration test according to OECD Guideline 209. The test substance concentrations tested were 3.2, 10, 32, 50 and 100 mg/L and a control. Based on the test results, the EC50 of the test substance was determined to be >100 mg/L.

Description of key information

The EC50 is > 100 mg/L in microorganisms of activated sludge.

Key value for chemical safety assessment

EC50 for microorganisms:

100 mg/L

Additional information

The toxicity of FAT 40557/A in activated sludge was determined in a GLP-compliant 30 minutes respiration test according to OECD Guideline 209. The test substance concentrations tested were 3.2, 10, 32, 50 and 100 mg/L and a control. Based on the test results, the EC50 of the test substance was determined to be >100 mg/L.