Registration Dossier

Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP guideline study with restrictions: The total exposure duration was 30 minutes only.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1994
Report Date:
1994

Materials and methods

Test guidelineopen allclose all
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Qualifier:
equivalent or similar to
Guideline:
ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)
Principles of method if other than guideline:
according to Annex of EG Directive 88/302/EWG
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder
Details on test material:
- Name of test material (as cited in study report): Carboxyethylisothiuroniumbetain
- Physical state: powder
- Analytical purity: > 98%
- Lot/batch No.: 88-3054

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The test substance was directly added to the test vessels.

Test organisms

Test organisms (species):
activated sludge, domestic
Details on inoculum:
- Laboratory culture: laboratory wastewater plant with municipal sewage
- Initial biomass concentration: 1g/L

Study design

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

Test conditions

Test temperature:
20 ± 2 °C
Nominal and measured concentrations:
Nominal: 250, 500 and 1000 mg/L
Details on test conditions:
TEST SYSTEM
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 3

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: OECD medium

EFFECT PARAMETERS MEASURED: Oxygen consumption after 30 minutes exposure time.
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol

Results and discussion

Effect concentrationsopen allclose all
Key result
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:
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
Results with reference substance (positive control):
- Results with reference substance valid? yes
- Relevant effect levels: EC20 = 4 mg/L, EC50 approx. 29 mg/L, EC80 > 100 mg/L

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The test substance did not show to inhibit aquatic microorganisms. Thus, the inhibition of the degradation activity of activated sludge in STPs is not anticipated.