Registration Dossier

Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study performed in accordance with OECD Guideline and compliant with GLP criteria.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2003
Report Date:
2003

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Test substance name: 2,6-Dimethyl-4-tert.-butylbenzylcyanid
- Aggregate state: Solid powder
- Colour: White
- Homogeneity: Homogeneous
- Storage conditions: Ambient

Sampling and analysis

Analytical monitoring:
not required

Test solutions

Details on test solutions:
The test substance was added in the required amount to the test vessel with about 180 mL deionized water. The mixture was stirred for 22 ± 2 hours to obtain an optimal solution. Then synthetic medium was added, the pH-value was adjusted to 7.5 ± 0.5, the inoculum was added and the test was started.

Test organisms

Test organisms (species):
activated sludge, domestic
Details on inoculum:
Activated sludge f rom laboratory wastewater plant treating municipal sewage. The inoculum was washed, brought to a concentration of 5 g/L dry substance and aerated during the night. 50 mL were added to a total volume of 250 mL to obtain a concentration of 1 g/L dry substance in the test.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
3 h

Test conditions

Test temperature:
20 ± 0.5 °C
pH:
6.8-8
Dissolved oxygen:
- Before adding inoculum: 6.8 - 7.2 mg/L (pH corrected)
- After 3 hours inubation: 8.0
Nominal and measured concentrations:
- Nominal concentration: 0 (control) and 1000 mg/L
Details on test conditions:
- Test vessels: Erlenmeyer-vessel (nominal volume 250 mL)
- Test volume: 250 mL
- Synthetic medium: 8 mL/vessel 100-fold concentrated OECD medium
- Oxygen concentration during aeration: >2.5 mg/L
- Oxygen concentration immediately before measurement: >6.5 mg/L
- Duration of the measurement of oxygen consumption: 8 - 10 min
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol

Results and discussion

Effect concentrationsopen allclose all
Duration:
180 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:
180 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
Details on results:
No change in oxygen consumption rate was observed at 1000 mg/L
Results with reference substance (positive control):
3-h EC20: ca. 3 mg/L
3-h EC50: ca. 22 mg/L

Applicant's summary and conclusion