Registration Dossier

Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2010-03-18 till 2010-03-26
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline and GLP-compliant study.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Type:
Constituent
Details on test material:
Partie number - Q101
Sample number - 1152
Purity - not stated
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:
no
Details on sampling:
Not applicable

Test solutions

Vehicle:
no

Test organisms

Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
Collected from the aeration tank of a domestic sewage treatment plant, Cologne- Stammheim. The sludge was allowed to settle and the supernatant was decanted. After centrifuging for 15 minutes at 3500 - 4500 rpm at 20 °C the supernatant was decanted. The required amount of sludge to achieve a 3 g/L (dry weight) of suspended solids was calculated and the required amount of sludge was made up to volume with deionised water. The sludge was stored at 20 ± 2°C, aerated and fed daily with synthetic medium until used.

Study design

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

Test conditions

Hardness:
Not applicable
Test temperature:
Test temperature range during the study was 19.7 - 19.9 °C
pH:
pH range in the definitive study was 7.5 - 7.6
Dissolved oxygen:
Results of dissolved oxygen measurements are presented in the results section.
Salinity:
Not applicable
Nominal and measured concentrations:
Nominal exposure concentrations were 100, 180, 320, 560 and 1000 mg/L.
Details on test conditions:
The study was performed in 300 mL glass Erlenmeyer flasks. The incubation time was 30 minutes with permanent aeration.
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol

Results and discussion

Effect concentrationsopen allclose all
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
Duration:
3 h
Dose descriptor:
EC10
Effect conc.:
163.8 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Remarks on result:
other: 7.9 - 301.4 mg/L
Results with reference substance (positive control):
The reference study was conducted using 3,5-dichlorophenol using nominal exposure concentrations of 2.5, 5.0, 10, 20 and 40 mg/L. Inhibition of respiration was 5.9, 12.3, 41.7, 75.4 and 89.1% in the 2.5, 5.0, 10, 20 and 40 mg/L nominal treatments. The 3 h EC50 for 3,5-dichlorophenol was for 12.0 mg/L, this is within the range 5 - 30 mg/L required in the guideline.
Reported statistics and error estimates:
The EC50 value of 2,3-dichlorobutadiene-1,3 was determined by observation of the data.

Any other information on results incl. tables

Respiration rates and percentage inhibition

Treatment

Nominal concentration (mg/L)

Respiration rate
(mg O2/L/h)

% inhibition

Control 1

0

24.9

-

Control 2

0

24.0

-

Control mean

-

24.4

-

% difference in controls

-

3.6

-

 

3,5-DCP

2.5

23.0

5.9

5

21.4

12.3

10

14.3

41.7

20

6.0

75.4

40

2.7

89.1

 

2,3-dichlorobutdiene-1,3

100

22.0

9.9

180

21.8

11.0

320

19.5

20.2

560

18.9

22.8

1000*

12.9

47.4

* the physico-chemical oxygen consumption has been determined at 4000 mg/L test item concentration. As no physic-chemical oxygen consumption was observed at the that test item concentration this observation also holds true for the lower test item concentrations.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The toxicity of 2,3-dichlorobutadiene-1,3 to activated sewage sludge was investigated in a respiration inhibition test according to EU Method C11 Activated sludge respiration inhibition 2008. Following three hours exposure to 2,3-dichlorobutadiene-1,3 the EC50 was observed to be > 1000 mg/L (based on nominal exposure concentrations), the corresponding EC10 was calculated to be 163.8 mg/L.
Executive summary:

The toxicity of 2,3-dichlorobutadiene-1,3 to activated sewage sludge was investigated in a respiration inhibition test according to EU Method C11 Activated sludge respiration inhibition 2008. Following three hours exposure to 2,3-dichlorobutadiene-1,3 the EC50was observed to be > 1000 mg/L (based on nominal exposure concentrations), the corresponding EC10was calculated to be 163.8 mg/L.