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: GLP guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report Date:
2012

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
Test material form:
other: White solid

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- 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, domestic
Details on inoculum:
- Laboratory culture: Activated sludge from the municipal wastewater treatment plant of Mannheim, Germany was collected from the aeration tank of the plant
- Preparation of inoculum for exposure: The activated sludge suspension was sieved with a fine woven mesh (mesh size about 1 mm). This suspension was pre-aerated over night at room temperature. At the next day the sludge suspension was washed once with tap water and the suspension was adjusted to 3 g/L dry matter.
- Pretreatment: None
- Initial biomass concentration: 1.5 g/L dry mass

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
180 min

Test conditions

Test temperature:
20.6°C - 21°C
Nominal and measured concentrations:
1000, 500, 250, 125, 62.5 mg/L as nominal concentration based on test substance without correction of purity.
100, 10, 1 mg/L as nominal concentration based on reference substance.
Details on test conditions:
TEST SYSTEM
- Test vessel: Glass-flasks (nominal volume 1000 mL)
- Aeration: incubation was started by aeration of the test vessels with pressure air
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 4
- No. of vessels per reference substance: 2

OTHER TEST CONDITIONS
- Adjustment of pH: no

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Test concentrations: 62.5, 125, 250, 500, 1000 mg/L
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol

Results and discussion

Effect concentrations
Duration:
180 min
Dose descriptor:
EC10
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Results with reference substance (positive control):
The EC50 of 3,5-dichlorophenol was 5 mg/L.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes