Disodium 6-(4,6-dichloro-1,3,5-triazin-2-ylamino)-1-hydroxy-2-(4-(2-(sulfonatooxy)ethylsulfonyl)phenylazo)naphthalene-3-sulfonate

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:

From Aug. 07, 1997 to Sep. 24, 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

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Commission Directive 88/302/EEC; Official Journal of the EC L 133 Part C (1988)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

No data

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Direct weighing
- Incubation time: 3 h with permanent aeration

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Origin: Sewage treatment plant at Frankfurt am Main-Sindlingen
- Method of cultivation: aeration tank of a waste water treatment plant treating predominantly domestic sewage (Wupper area water authority)
- Preparation of inoculum for exposure: Sediment from activated sewage sludge was washed three times by centrifuging and resuspending in water with 0.9 % NaCl
- Pretreatment: Corresponding to the cited test guideline
- State of acclimatization: Not pre-adapted to the test substance or the reference substance
- pH of the suspension before application: 6.6
- Amount used : 450 mI/L sludge suspension
- Content of suspended solids: 27.78 h/L(centrifuged wet matter)
- Content of suspended solids: 3.56 g/L (dry matter)
- Content in the final test volume: 1.6 g/L(dry matter)

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Remarks on exposure duration:

-

Post exposure observation period:

None

Hardness:

No data

Test temperature:

20.6-21.2 °C

pH:

8.0-8.2

Dissolved oxygen:

No data

Salinity:

No data

Nominal and measured concentrations:

Nominal: 250, 500, 10000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass bottles
- Type (delete if not applicable): Closed
- Material, size, headspace, fill volume: Diameter of 60 mm and a grounded neck (NS 29), height 170 mm and a total volume of approx. 480 mL, Test volume of 200 mL each batch
- Aeration: 50 L/h, only during the incubation period
- Temperature control: The temperature control was performed by a water circulating thermostate
- Oxygen measurements : With oxygen electrodes, connected to oximeters and two channel recorders
- Monitoring : During the measuring period the oxygen concentration curves were plotted by the recorders
- Respiration rate: The slope of the linear part of the respiration curves accorded to the corresponding respiration rates
- Measurements of the pH: pH-meters

OTHER TEST CONDITIONS
- Adjustment of pH: Yes

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol (5, 20, 30 mg/L)

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: -

Duration:

3 h

Dose descriptor:

other: EC20 and EC80

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: -

Details on results:

- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No
- A significant inhibition could not be observed.
- The documented EC-values were above the highest tested concentration.

Results with reference substance (positive control):

- Results with reference substance valid: Yes
- EC50: 19 mg/L

Reported statistics and error estimates:

The EC values are determined by probit analysis according to Finney

Table 1. DOC-analyses in samples from the test system

Nominal concentration after addition of the stock solution	Analyses at the test start: DOC	Analyses at the test end: DOC	Deviation between start and end of test [%]
1000	250.7	266.5	+ 6.3
500	125.1	130.8	+ 4.6
250	64.1	64.9	+ 1.2

 

A significant decrease (> 20 %) of the dissolved organic carbon of the test substance during the test period was not observed.

Table 2:  Respiration rates and inhibition of respiration of test and reference material concentration

Controls/Tests [mg/L]	Activity ( A ) [mgO2/(L.h)]	Respiration inhibition [%]	Means
Blank 1	41.3	-	40.9
Blank 2	40.8	-
Blank 3	40.5	-
Ref. Sub, 5 mg/L	37.2	9.0	-
Ref. Sub, 20 mg/L	18.0	56.0	-
Ref. Sub, 30 mg/L	15.5	62.2	-
1000 (A) 1000 (B)	34.8 36.1	15.0 11.8	13.4
500 (A) 500 (B)	37.1 36.0	9.3 11.9	10.6
250 (A) 250 (B)	34.5 34.5	15.6 15.6	15.6

(A)/(B): parallel batches. The corresponding amounts of test substance in the batches are given in mg/L 

Validity criteria fulfilled:

yes

Conclusions:

Under the test conditions, the EC50 of the test substance to activated sludge (domestic sewage treatment plant) is > 1000 mg/L, which was the highest concentration in the test

Executive summary:

A study was performed to assess the toxicity of test substance to bacteria according OECD Guideline 209 and Commission Directive 88/302/EEC part C, EC Gazette L 133 (1988) in compliance with GLP.

The domestic activated sludge collected from sewage treatment plant at Frankfurt am Main-Sindlingen was exposed to test substance at different concentrations. The respiratory rate inhibition of sludge microorganisms was determined after 3 h incubation time under static conditions. The nominal test concentrations were 0, 250, 500 and 1000 mg/L.

Test substance showed 13.4 % respiration inhibition of activated sludge at a concentration of 1000 mg/L. The documented EC-values (EC20, EC50 and EC80) were above the highest tested concentration (1000 mg/L)

The 3 h EC50 value for the reference material, 3, 5-Dichlorophenol was 19 mg/L. 

Under the test conditions, the EC50 of the test substance to activated sludge (domestic sewage treatment plant) is > 1000 mg/L, which was the highest concentration in the test. 

Description of key information

The EC50 of the test substance to activated sludge (domestic sewage treatment plant) is > 1000 mg/L, which was the highest concentration in the test (Dr. Hryk R, 1997)

Key value for chemical safety assessment

EC50 for microorganisms:

1 000 mg/L

EC10 or NOEC for microorganisms:

1 000 mg/L

Additional information

A study was performed to assess the toxicity of test substance to bacteria according OECD Guideline 209 and Commission Directive 88/302/EEC part C, EC Gazette L 133 (1988).

The domestic activated sludge collected from sewage treatment plant at Frankfurt am Main-Sindlingen was exposed to test substance at different concentrations. The respiratory rate inhibition of sludge microorganisms was determined after 3 h incubation time under static conditions. The nominal test concentrations were 0, 250, 500 and 1000 mg/L. T

Test substance showed 13.4 % respiration inhibition of activated sludge at a concentration of 1000 mg/L. The documented EC-values (EC20, EC50 and EC80) were above the highest tested concentration (1000 mg/L)

The 3 h EC50 value for the reference material, 3, 5-Dichlorophenol was 19 mg/L. 

The EC50 of the test substance to activated sludge (domestic sewage treatment plant) is > 1000 mg/L, which was the highest concentration in the test (Dr. Hryk R, 1997)