Registration Dossier

Diss Factsheets

Ecotoxicological information

Toxicity to microorganisms

Currently viewing:

Administrative data

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:
10 September 1998 to 11 September 1998
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted to EU & OECD test guidance in compliance with GLP.
Qualifier:
according to guideline
Guideline:
other: Commission Directive 88/302/EEC; Official Journal of the EC L 133, Part C: Biodegradability: Test for inhibition of oxygen consumption (corresponds for the most part to the test method OECD 209)
Deviations:
no
Principles of method if other than guideline:
A defined quantity of activated sludge is mixed with synthetic medium and the respiratory rate is measured. This rate is compared to those measured in test preparations with various concentrations of the test substance. In order to check the sensitivity of the activated sludge used, 3.5-dichlorophenol is used as a reference substance.
Deviations from the SOPs with reasons : Incubation time of 3 hours with permanent aeration instead of 30 minutes incubation time. Reason: Recommendation of the German member state authority.
GLP compliance:
yes
Analytical monitoring:
no
Details on sampling:
The test concentrations where not confirmed by analytical techniques or sampling.
Vehicle:
no
Details on test solutions:
The test substance has been added to about 130 ml deionized water and stirred overnight before testing (equilibration phase).
Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
Type: activated sludge (mixed population of different microorganisms)
Origin: aeration tank of a waste water plant treating predominantly domestic sewage (Wupper area water authority)
Pretreatment: none
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
3 h
Post exposure observation period:
No post exposure observation period
Hardness:
Not reported.
Test temperature:
20.9 - 21.0
pH:
7.5 - 8.0
Dissolved oxygen:
Start of study 5.8 - 6.3 mg O2/l
End of study 2.6 - 2.9 mg O2/l
Salinity:
Not applicable.
Nominal and measured concentrations:
Test concentrations (mg/l): 100, 1000, 10000
Test substance concentration in physico-chemical oxygen consumption control (mg/l): 10000
Details on test conditions:
A defined quantity of activated sludge is mixed with synthetic medium and the respiratory rate is measured. This rate is compared to those measured in test preparations with various concentrations of the test substance. In order to check the sensitivity of the activated sludge used, 3.5-dichlorophenol is used as a reference substance.

Incubation time of 3 hours with permanent aeration instead of 30 minutes incubation time. Reason: Recommendation of the Environmental Federation Office.

The study is carried out with nominal weights. The test concentrations are not confirmed by chemical analysis.

Test concentrations (mg/l): 100, 1000, 10000
** Test substance concentration in physico-chemical oxygen consumption control (mg/l): 10000

Type of application: direct weighing
Test concentration of the activated sludge: 320 mg/l
Test temperature: 20±2°C
Incubation time : 3 hours with permanent aeration

** The physico chemical oxygen consumption control is carried out, since some substances can also consume oxygen by chemical reactivity. In order to be able to tell the difference between physico chemical oxygen consumption and biological oxygen consumption (respiration), at least the maximum concentration of the test substance is tested without activated sludge.
Reference substance (positive control):
yes
Remarks:
3.5-dichlorophenol
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
> 10 000 mg/L
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Details on results:
Details under any other information
Results with reference substance (positive control):
Details under any other information
Reported statistics and error estimates:
No data

Measured values of test substance / control / reference substance

 

Test concentration [mg/l]

Initial concentration* [mg/250 ml]

O2-start [mg O2/l]

O2-end [mg O2/l]

Time [min.]

Temp. [°C]

pH

Test substance

100

25

6.1

2.6

6

20.9

8.0

1000

250

6.3

2.8

6

20.9

7.9

10000

2500

5.8

2.98

6

21.0

7.8

Control 1

 

 

6.1

2.9

6

21.0

7.9

Control 2

 

 

6.2

2.6

6

20.9

8.0

Physio-chemical oxygen consumption control

10000

2500

9.2

9.2

9

21.0

7.5

Reference substance

5

2.5

6.0

3.1

6

21.0

8.0

10

5

6.4

4.5

5

20.9

8.0

20

10

8.6

7.8

7

20.9

8.1

Comments:      Because of strong respiration of the activated sludge only 0.32 g/l ss were used.

The test substance has been added to about 130ml deionised water and stirred overnight before testing (equilibration phase).

* Volume added in ml of 3.5-Dichlorophenol stock solution (500 mg/l), total volume 250 ml.

 

STUDY EVALUATION

Test Substance: T-9601

Reference substance: 3.5-Dichlorophenol

 

Test concentration [mg/l]

Respiratory rate [mg/l h]

Phys. chem. O2-consumption [mg/l h]

Respiratory rate- phys. chem. O2-consumption [mg/l h]

Inhibition [%]

Test substance

100

35.0

0.0 *

35.0

0.0

1000

35.0

0.0 *

35.0

0.0

10000

29.0

0.0

29.0

14.7

Control, mean

 

34.0

 

Control 1

36.0

Control 2

36.0

Reference substance

5

29.0

-

-

14.7

10

22.8

-

-

32.9

20

6.9

-

-

79.7

Comments relevant to result:

Purity of test substance: 94.7%

Purity of the reference substance: 97%

Test concentrations are given as nominal concentrations and have not been confirmed by analytical methods.

* The physico-chemical oxygen consumption is determined at 10000 mg/l test substance. No physic-chemical oxygen consumption has been determined. Therefore lower concentrations of the test substance cause no physic-chemical oxygen consumption (deduced values).

Validity criteria fulfilled:
yes
Conclusions:
Toxicity of T-9601 to activated sludge: EC 50 > 10000 mg/l
Executive summary:

Study conducted to Commission Directive 88/302/EEC; Official Journal of the EC L 133, Part C: Biodegradability: Test for inhibition of oxygen consumption (corresponds for the most part to the test method OECD 209). Study in compliance with GLP.

 

A defined quantity of activated sludge is mixed with synthetic medium and the respiratory rate is measured. This rate is compared to those measured in test preparations with various con­centrations of the test substance. In order to check the sensitivity of the activated sludge used, 3.5-dichlorophenol is used as a reference substance.

 

Toxicity of T-9601 to activated sludge : EC 50 > 10000 mg/l

Description of key information

Toxicity of T-9601 to activated sludge: EC 50 > 10000 mg/L

Key value for chemical safety assessment

EC50 for microorganisms:
10 000 mg/L

Additional information

Study conducted to Commission Directive 88/302/EEC; Official Journal of the EC L 133, Part C: Biodegradability: Test for inhibition of oxygen consumption (corresponds for the most part to the test method OECD 209). Study in compliance with GLP.


 


A defined quantity of activated sludge is mixed with synthetic medium and the respiratory rate is measured. This rate is compared to those measured in test preparations with various con­centrations of the test substance. In order to check the sensitivity of the activated sludge used, 3.5-dichlorophenol is used as a reference substance.


 


Toxicity of T-9601 to activated sludge : EC 50 > 10000 mg/L