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Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: guideline study, GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1996
Report date:
1996

Materials and methods

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

Test material

Constituent 1
Chemical structure
Reference substance name:
2-[(o-nitrophenyl)azo]-p-cresol
EC Number:
215-863-0
EC Name:
2-[(o-nitrophenyl)azo]-p-cresol
Cas Number:
1435-71-8
Molecular formula:
C13H11N3O3
IUPAC Name:
4-methyl-2-[(2-nitrophenyl)diazenyl]phenol
Details on test material:
- Name of test material (as cited in study report): TKA 40136, Monoazo 3113
- Physical state: Red-brownish solid
- Analytical purity: > 95%
- Lot/batch No.: Pa 369
- Storage condition of test material: At room temperature in the dark
- Expiry date: 1997-11-1

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no

Test organisms

Test organisms (species):
activated sludge, domestic
Details on inoculum:
- Preparation of inoculum for exposure: The sludge was coarsely sieved and washed with tap-water. A small amount of the sludge was weighed and dried at ca. 105°C. From this result the amount of suspended solids was calculated: the level was 3.9 g/l of sludge. The batch of sludge was used on subsequent days (maximum four days), therefore 50 ml of synthetic sewage feed was added to each litre of activated sludge at the end of each working day. The sludge was kept aerated at 20 + 2°C until use. Before use the pH was checked (7.9).

Study design

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

Test conditions

Test temperature:
20 ± 2 °C
Dissolved oxygen:
Oxygen concentration during aeration: > 2,5 mg/l
Oxygen concentration immediately before measurement: > 6,5 mg/l
Nominal and measured concentrations:
Nominal: ca. 100 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: Erlenmeyer-vessel (nominal volume 250 ml)
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 3

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
Synthetic medium: 8 ml/vessel 100-fold concentrated OECD medium
Reference substance (positive control):
no

Results and discussion

Effect concentrations
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Details on results:
- Any observations that might cause a difference between measured and nominal values: The tested substance had a very low water solubility. Therefore, the substance was added quantitatively
Results with reference substance (positive control):
EC50 = 9.75 mg/L, 95 % CL: 8.32-11.42 mg/L

Applicant's summary and conclusion