Registration Dossier

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:
1 (reliable without restriction)

Data source

Reference Type:
study report
Report Date:

Materials and methods

Test guideline
according to
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
GLP compliance:
yes (incl. certificate)

Test material

Test material form:
solid: particulate/powder

Study design

Oxygen conditions:
Inoculum or test system:
sewage, domestic (adaptation not specified)
Details on inoculum:
The inoculum: Secondary effluent, microorganisms from a domestic waste water treatment plant.
Origin: The secondary effluent was supplied from the sewage plant for domestic sewage in Veszprém, Hungary.
Conditioning: The secondary effluent used for this study was allowed to settle approximately for an hour, then the decanted effluent was aerated until use (not later than an hour).
Duration of test (contact time):
ca. 28 d
Initial test substance concentration
Initial conc.:
ca. 2.1 mg/L
Based on:
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
The test was carried out in an incubator and controlled environment room (during the formulation and oxygen measuring) at a temperature of 22 ± 2 °C according to guideline. The test flasks were placed into an incubator and kept at 22.0 - 23.1°C, in the dark. The temperature was measured on weekdays during the experiment.
The oxygen concentration of test water was 8.7 mg/L at the start of the test.
The pH value of the test water was checked prior start of the experiment. The pH of the test water was 7.20.
The test conditions were measured with suitable instruments and documented in the raw data.
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

% Degradation
Key result
% degradation (O2 consumption)
ca. 35.3
Sampling time:
28 d

Applicant's summary and conclusion

Validity criteria fulfilled:
Interpretation of results:
not readily biodegradable
Executive summary:

The test item was investigated for its ready biodegradability in a Closed Bottle Test over a period of 28 days under anaerobic conditions (OECD 301D method). The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. As a reference item Sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control.

Under the test conditions the percentage biodegradation of the test item reached a mean of 35.3 % after 28 days based on the ThOD of the test item. According to the test guidelines the pass level for ready biodegradability is removal of 60 % ThOD. Therefore, the test item is considered not readily biodegradable.