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Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study

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 301 B (Ready Biodegradability: CO2 Evolution 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

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge: Laboratory wastewater plant treating municipal and synthetic sewage
- Preparation of inoculum for exposure: Inoculum was pre-aerated two days before the start of the test
- Initial cell/biomass concentration: 30 mg/L dry substance
Duration of test (contact time):
28 d
Initial test substance concentrationopen allclose all
Initial conc.:
25 mg/L
Based on:
test mat.
Initial conc.:
ca. 15 mg/L
Based on:
other: TOC
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST CONDITIONS
- Test temperature: 22 ± 2 °C

TEST SYSTEM
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: A mixture of oxygen and nitrogen was led through a botlle, containing 0.5-1 L 0.0125 M Ba(OH)2 solution to trap CO2 which might be present in small amounts. The CO2-free air was sparged through the scrubbing solutions at a constant rate.
- Measuring: Carbon dioxide trap (Barium hydroxide), titration with 0.05 M HCl
- Test performed in open system: no

SAMPLING
- Sampling frequency: Every second or third day up to day 10, thereafter at least every fifth day

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: no
- Other: Toxicity control
Reference substance
Reference substance:
other: 40 mg/L Sodium acetate

Results and discussion

% Degradation
Parameter:
% degradation (CO2 evolution)
Value:
>= 7.3 - <= 9.7
Sampling time:
28 d

BOD5 / COD results

Results with reference substance:
30.2% after 5 days, 89.1% after 14 days and > 100% after 28 days

Applicant's summary and conclusion

Interpretation of results:
other: Not readily biodegradable under this test conditions