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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
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
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
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
Qualifier:
according to guideline
Guideline:
other: ISO 11734
GLP compliance:
not specified
Oxygen conditions:
anaerobic
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:
DOC
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 CONDITIONS
-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.

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

Method

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

Results

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