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Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
12 May to 9 June 1988
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study report is conducted to OECD and EEC guidelines and contains a statement of GLP compliance

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guideline
according to guideline
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Version / remarks:
GLP compliance:

Test material

Constituent 1
Chemical structure
Reference substance name:
EC Number:
EC Name:
Cas Number:
Molecular formula:
Details on test material:

- Physical state: white powder
- Analytical purity: not known
- Impurities (identity and concentrations): not known
- Composition of test material, percentage of components: not known
- Lot/batch No.: not known
- Expiration date of the lot/batch: not known
- Storage condition of test material: in a glass container at room temperature in the dark
- Other:

Study design

Oxygen conditions:
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Activated sludge bacteria from sewage treatment plant treating predominantly domestic sewage
- Method of cultivation: No information
- Storage conditions: No information
- Storage length: Collected on day of study.
- Preparation of inoculum for exposure: The sample was allowed to settle and the supernatant filtered through Whatman GFA filter paper (first 250ml discarded)
- Pretreatment: No information
- Concentration of sludge: no information
- Initial cell/biomass concentration: no information
- Water filtered: yes
- Type and size of filter used, if any: Whatman GFA paper
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
2 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
- Composition of medium: Innoculated test media treated with 1 drop of activated sludge filtrate at a rate of 1 drop per litre
- Additional substrate: None
- Solubilising agent (type and concentration if used): None used
- Test temperature: 21 C
- pH: Not reported
- pH adjusted: yes/no Not reported
- Aeration of dilution water: no
- Suspended solids concentration: none reported
- Continuous darkness: yes
- Concentration: 2 mg/l

- Culturing apparatus: 280 ml BOD bottles incubated in a water bath at 21 +/- 1 deg C
- Number of culture flasks/concentration: two
- Method used to create aerobic conditions: yes
- Method used to create anaerobic conditions: no
- Measuring equipment: Yellow springs BOD probe (Model 54)
- Test performed in closed vessels due to significant volatility of test substance: yes
- Test performed in open system: no
- Details of trap for CO2 and volatile organics if used: Not used
- Other:

- Sampling frequency: 0, 5, 15 and 28 days
- Sampling method: measuring dissolved oxygen concentration
- Sterility check if applicable: N/A
- Sample storage before analysis: Not reported
- Other:

- Inoculum blank:
Inoculated dilution water
Inoculated dilution water and filter paper
- Abiotic sterile control: None
- Toxicity control: Sodium Benzoate
- Other:

Reference substance
Reference substance:
other: Sodium Benzoate (3mg/l)

Results and discussion

% Degradation
% degradation (O2 consumption)
Sampling time:
28 d
Details on results:
Dissolved oxygen measurements for the test substance and standard substance solution, together with the inoculated and non-inoculated blank controls were measured at 0, 5, 15 and 28 days.
Oxygen depletions in the inoculated and non-inoculated control series were within prescribed limits.

BOD5 / COD results

Results with reference substance:
Sodium benzoate attained 82% degradation within 28 days.

Any other information on results incl. tables

  Culture media      Day 5   Day 15   Day 28
Dilution  water without inoculum  O2 depletion (mg O2/ l) % degradation  0.025-  0.175-  0.200-
  Dilution  water with inoculum   O2depletion (mg O2/ l) % degradation  0.175-  0.250-  0.375-
  Dilution  water with inoculum and filter paper   O2depletion (mg O2/ l) % degradation  0.275- 0.275 -  0.350-
 Test substance (2 mg/l) with inoculum   O2depletion (mg O2/ l) % degradation  0.52512 0.65015  0.62515 
  Standard substance (3 mg/l) with inoculum   O2depletion (mg O2/ l) % degradation 3.62573  3.90078  4.10082 

Applicant's summary and conclusion

Validity criteria fulfilled:
Interpretation of results:
other: not readily biodegradable under the conditions of the test
The test substance attained 15% biodegradation after 28 days but is not readily biodegradable under the conditions of the test.
Executive summary:

The substance was tested according to the closed bottle test to assess the ready biodegradability of the substance over a period of 28 days. A reference substance, sodium benzoate, was used to demonstrate that the test system is effective. The test substance attained 15% biodegradation after 28 days at a temperature of 21 deg C. Under the conditions of the test the substance is considered not readily biodegradable.