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Biodegradation in water: screening tests

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biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
May 18, 2005 - July 07, 2005
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
according to
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Version / remarks:
adopted July 17, 1992
according to
EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)
Version / remarks:
July 31, 1992
GLP compliance:
yes (incl. certificate)
Oxygen conditions:
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
The activated sludge used for this study was washed by centrifugation and the supernatant liquid phase was decanted. The solid material was resuspended in tap water and again centrifuged. This procedure was repeated twice. An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge to its dry weight was determined. Based on this ratio, calculated aliquots of washed sludge suspension, corresponding to 1.5 g dry material per litre were mixed with test water and then aerated until use.
Duration of test (contact time):
28 d
Initial conc.:
103 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
Temperature: 21.5-21.8°C
Light conditions: darkness
pH: 7.6 (start), 7.6-7.8 (end)

The amounts of test item and reference item were directly weighed into the test flasks. No emulsifiers or solvents were used, but the solutions were dispersed by stirring to achieve a homogeneous solution of the test item. The closed test flasks were incubatd in a climatised room under contiuous stirring.
Reference substance:
Key result
% degradation (O2 consumption)
Sampling time:
28 d
Details on results:
After correction for the mean biochemical oxygen demand of the inoculum controls (based on ThOD-NH4) no biodegradation greater than 4% was observed during the test.
Results with reference substance:
The reference item Aniline was sufficiently degraded to 96 % after 14 days and to 106 % after 28 days of incubation, thus confirming the suitability of the used activated sludge inoculum.
Validity criteria fulfilled:
Interpretation of results:
not readily biodegradable
The test item is not considered to be readily biodegradable.
Executive summary:

The informtion for this endpoint study record was obtained from an experimental study. The OECD GLP criteria were met and the methods applied are fully compliant with OECD TG 301F.

The test item is not considered to be readily biodegradable.

Description of key information

The test item is not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed
Type of water:

Additional information