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Biodegradation in water: screening tests

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biodegradation in water: screening tests
Type of information:
other: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
From June 29 to August 24, 1995
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study
The test was conducted by means of Read Across approach. The reliability of the source study report is 2. Further information was attached at section 13
according to guideline
other: ISO 11734
GLP compliance:
not specified
Oxygen conditions:
Inoculum or test system:
anaerobic bacteria
Details on inoculum:
- Source of inoculum: Municipal sewage Kriftel
- Storage conditions: at 35°C +/- 2°C thermostat Incubator, the temperature has remained during the test in range of 33.0°C- 37.0°C
- Storage length: 7 days- Preparation of inoculum for exposure: bacterial biomass anaerobic digester of a semi-continuous operation, through a 0.5 mm sieve to separate coarse particles, washed, resuspended to the DOC value of the class does not exceed 10 mg/L (C)100 mL/L of anaerobic inoculum suspension with a solids content of 32.4 g/L, corresponding to 3.24 The final volume in the dry mass of the audit method.
- Pretreatment:the inoculum was 7 days for depletion of carbon in the incubatormixed at 35 ± 2 °C- Type and size of filter used, if any: 0.5 mm
Duration of test (contact time):
ca. 56 d
Initial conc.:
113 mg/L
Based on:
Initial conc.:
500 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
CO2 evolution
Parameter followed for biodegradation estimation:
CH4 evolution
Details on study design:
-Test vessel: 1000 mL glass tank with magnetic stirrer
- Composition of medium: ISO 11734 Punkt 6.2 Testmedium
- Test temperature: 33 - 37 °C
- pH: 7.2
- pH adjusted: yes
- Suspended solids concentration: 100 mL/L
- Stock solution: 2000 mg/L; 2000 mg/800 mL weighed in highly purified water, measured pH 4.3; adjusted to pH 7.2, stirred for 2 hours at 22°C, measured pH 7.2, filled up to 1000 mL and used as stock solution.

- Number of culture flasks/concentration: 3
- Details of trap for CO2 and volatile organics if used: graduated gas mouse
- Inoculum blank: yes
Reference substance:
benzoic acid, sodium salt
% degradation (CO2 evolution)
< 20
Sampling time:
56 d
% degradation (CH4 evolution)
< 20
Sampling time:
56 d
Results with reference substance:
> 60 % gas formation
Validity criteria fulfilled:
Interpretation of results:
not readily biodegradable
A significant anaerobic biodegradation was not observed. The formation of gas within 56 days remained below 20% of the theoretical maximum.
Executive summary:


The test substance was tested for biodegradation in anaerobic conditions according to the ISO 11734.


The formation of gas within 56 days remained below 20 % of the theoretical maximum. A significant anaerobic biodegradation was not observed.

Description of key information

Not readily biodegradable

Key value for chemical safety assessment

Additional information