Pentasodium 7-(4-(4-(5-amino-4-sulfonato-2-(4-((2-(sulfonato-ethoxy)sulfonyl)phenylazo)phenylamino)-6-chloro-1,3,5-triazin-2-yl)amino-2-ureidophenylazo)naphtalene-1,3,6-trisulfonate

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 March 1996 to 12 Jun 1996

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

Qualifier:

according to guideline

Guideline:

other: EEC Directive 87/302 No. L133/118 "Respiration Inhibition Test".

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Identity: FAT 40'549/A
Batch No: TV1
Expiration date: 01 Jan 2001
Stability in water: for atleast 48 hours
Solubility in water: approximately 90 mg/L at 20 degree celcius.
Aggregate state under storage conditions: solid (powder)
Colour: yellow brown.
Storage conditions: at room temperature
Safety precautions: Routine hygenic procudures are sufficient to assure personnel health and safety.

Analytical monitoring:

no

Details on sampling:

After 30 minutes of aeration at 20.0 °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 concentration.

Vehicle:

no

Details on test solutions:

Stock Solution: 500 mg FAT 40'549/A was weighed into a 1000 ml volumetric flask, and the flask was filled to volume with bidistilled water. As a result, a clear orange solution in bidistilled water with a concentration of 500 mg/l was prepared.

Test organisms (species):

activated sludge, domestic

Details on inoculum:

The test was performed with aerobic activated sludge from a domestic waste water treatment plant (ARA Ergolz II, Füllinsdorf / Switzerland).

Preparation of Sludge: The 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 ratio, calculated aliquots of washed sludge suspension, corresponding to 4 g dry material per litre, were made up with Soerensen buffer (pH 7). 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 7.7 with 0.5 mol/l H2S04.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

30 min

Hardness:

no data

Test temperature:

20.0 °C

pH:

7.9 - 8.2

Salinity:

no data

Nominal and measured concentrations:

nominal: 3.2, 10, 32, 50, 100 mg/l

Details on test conditions:

Synthetic sewage: 16 g peptone, 11 g meat extract, 3 g urea, 0.7 g NaCI, 0.4 g CaCI2 • 2H2O, 0.2 g MgS04 • 7H2O and 2.8 g K2HPO4 filled up to a final volume of 1 I with bidistilled water.

Test Apparatus: The test was carried out in glass flasks (>500 ml) aerated with an air-flow of about 0.2 l/minute instead of 0.5 l/minute to prevent possible foam development. The test vessels were labelled with the RCC project number and the necessary additional information to assure unmistakable identification.

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

Details on results:

The respiration rate of aerobic waste water bacteria was not inhibited (-0.2 % to -12.0 %), when exposed to the test article concentrations in the range from 100 to 3.2 mg/L. The EC50 (30 minutes) was therefore determined to be >100 mg/L.

Results with reference substance (positive control):

The EC50 (30 minutes) determined by the Logit model was calculated to be 18.9 mg/L with the 95 % confidence limits of 17.5 - 20.3 mg/L.

The dose response line was: Logit = -3.79 + 1.289 x log (dose). The 95 % confidence limits for the slope were 1.285 -1.292.

Validity criteria fulfilled:

yes

Conclusions:

The respiration rate of aerobic waste water bacteria was not inhibited when exposed to the test article concentrations in the range from 3.2 to 100 mg/L. The EC50 (30 minutes) was therefore determined to be >100 mg/L and the EC10 >= 100 mg/L.

Executive summary:

The inhibitory effect of FAT 40549/A on aerobic waste water bacteria of activated sludge was investigated in a respiration test. This test was conducted in accordance with OECD test guideline 209 in a GLP certified laboratory.

This study examined nominal test article concentrations in the range from 3.2 mg/L to 100 mg/L. The respiration rate of aerobic waste water bacteria was not inhibited when exposed to the test article concentrations in the range from 3.2 to 100 mg/L.

The EC50 (30 minutes) was therefore determined to be >100 mg/l. The EC50 (30 minutes) for the reference compound 3,5-dichlorophenol, which was tested under the same conditions as the test article, was found to be at 18.9 mg/L and therefore lies within the range of 5 - 30 mg/L recommended by the test guidelines.

Description of key information

The EC50 (30 minutes) was determined to be >100 mg/l and the EC10 was found >=100 mg/l as no reduction in respiration rate was observed. 

Key value for chemical safety assessment

EC50 for microorganisms:

100 mg/L

EC10 or NOEC for microorganisms:

100 mg/L

Additional information

The inhibitory effect of FAT 40549/A on aerobic waste water bacteria of activated sludge was investigated in a respiration test. This test was conducted in accordance with OECD test guideline 209 in a GLP certified laboratory.

This study examined nominal test article concentrations in the range from 3.2 mg/L to 100 mg/L. The respiration rate of aerobic waste water bacteria was not inhibited when exposed to the test article concentrations in the range from 3.2 to 100 mg/L.

The EC50 (30 minutes) was therefore determined to be >100 mg/l. The EC50 (30 minutes) for the reference compound 3,5-dichlorophenol, which was tested under the same conditions as the test article, was found to be at 18.9 mg/L and therefore lies within the range of 5 - 30 mg/L recommended by the test guidelines.