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:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report Date:
2017

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation))
Deviations:
yes
Remarks:
The oxygen content measurement time was higher than 10 minutes (i.e. 10.1 - 10.5 min). An influence to the results of this study can be excluded.
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no
Details on test solutions:
Application of the test substance: Direct addition by initial weight into the test flasks. The test substance was weighed in the required amounts for the test concentrations directly to the test vessels.

Test organisms

Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
Origin of inoculum: aeration tank of the wastewater treatment plant of Mannheim, Germany

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
180 min

Test conditions

Test temperature:
19.9 - 20.7 °C
pH:
7.5
Dissolved oxygen:
> 2 mg/L during aeration
Nominal and measured concentrations:
Nominal: 1000, 500, 250, 125, 62.5 mg/L and control
Reference substamce: 100, 10 and 1 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: glas beaker (nominal 1 L)
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: 500 ml fill volume
- Aeration: yes
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- No. of vessels per toxic control (replicates): 6
- Sludge concentration (weight of dry solids per volume): 1.5 g/L dry weight


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to OECD 209
- Particulate matter: not applicable

OTHER TEST CONDITIONS
- Adjustment of pH: yes

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : oxygen consumption
TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
3 h
Dose descriptor:
EC10
Effect conc.:
40 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth inhibition
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
280 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth inhibition
Results with reference substance (positive control):
The EC50 of 3,5-dichlorophenol was 8.2 mg/L
Reported statistics and error estimates:
The consumption rates were used for the determination of the ECx by the probit method based on Finney with the software TOXRAT Professional 2.10. The effect concentrations were given with an accuracy of 2 significant digits.

Applicant's summary and conclusion