Registration Dossier

Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
13 August 1999
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP and guideline compliant study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1999
Report Date:
1999

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Deviations:
no
Qualifier:
according to
Guideline:
ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Dimethylolpropionsaure (Bis-MPA)
- Physical state: white solid
- Analytical purity: 99.4%
- Lot/batch No.: SE 8069
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
Not applicable

Sampling and analysis

Analytical monitoring:
not required
Details on sampling:
Not applicable

Test solutions

Vehicle:
no

Test organisms

Test organisms (species):
activated sludge
Details on inoculum:
Activated sludge was taken from laboratory wastewater plants treating municipal sewage.

The inoculum was washed, brought to a concentration of 5 g/I dry substance and aerated for about 24 hours. 50 ml were added to a total volume of 250 ml to obtain a concentration of 1 g/I dry substance in the test.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
30 min
Post exposure observation period:
Not applicable

Test conditions

Hardness:
Not applicable
Test temperature:
20 ± 2 °C
pH:
See results tables
Dissolved oxygen:
See results tables
Salinity:
Not applicable
Nominal and measured concentrations:
Nominal concentration of dimethylolpropionsaure used: 1000 mg/L
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol

Results and discussion

Effect concentrationsopen allclose all
Duration:
30 min
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
Duration:
30 min
Dose descriptor:
other: EC20
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Duration:
30 min
Dose descriptor:
other: 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
Details on results:
Not applicable
Results with reference substance (positive control):
Reference substance after 30 min incubation time:
 
EC20(mg/L) - 1.5
EC50(mg/L) - 5.5
EC80(mg/L) - 45

 
 
Reported statistics and error estimates:
Not aplicable

Any other information on results incl. tables

pH values during the study

Vessel number

BC1

BC2

BC3

TS1

pH value before adding the inoculum:
before correction:
after correction:


6.7
7.2


6.7
7.2


6.7
7.4


6.8
7.2

pH value after 30 minute incubation

-

-

-

7.5

 

Results of the definitive test after 30 min incubation period with 1000 mg/L dimethylolpropionsaure

Vessel no.

mv BC

TS1

RS1

RS2

RS3

Oxygen concentration start (mg O2/L)

-

7.8

7.4

8.2

8.7

Oxygen concentration after 6 min (mg O2/L)

-

5.8

5.7

7.5

8.5

Oxygen consumption rate (mg O2/L x 6 min)

1.9

2.0

1.7

0.7

0.2

Oxygen consumption rate (mg O2/L x h)

19

20

17

7

2

Specific oxygen consumption rate (mg O2/g x h)

19

20

17

7

2

Change in oxygen consumption rate compared with the blank control (%)

-

-5

11

63

89

mv BC = mean value of blank control

TS = test substance

RS = reference number

 

Reference substance after 30 min incubation time

 

EC20(mg/L)

EC50(mg/L)

EC80(mg/L)

EC20(mg/L)

Reference substance

ca. 1.5

ca. 5.5

ca. 45

100

 

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
The EC50 for the reference inhibitor, 3,5-dichlorophenol was in the range of 5 - 30 mg/L.
Conclusions:
Activated sludge obtained from laboratory wastewater plants treating municipal sewage was exposed in a 30 -minute inhibition of oxygen consumption test to 1000 mg dimethylolpropionsaure/L. The test design followed OECD 209 guidelines. The 30 -minute EC50 based on respiration inhibition was >1000 mg/L (the highest nominal exposure concentration tested).
Executive summary:

Activated sludge obtained from laboratory wastewater plants treating municipal sewage was exposed in a 30 -minute inhibition of oxygen consumption test to 1000 mg dimethylolpropionsaure/L. The test design followed OECD 209 guidelines. The 30 -minute EC50 based on respiration inhibition was >1000 mg/L (the highest nominal exposure concentration tested).