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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:
Sep 28, 2010 - Dec 08, 2010
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
according to guideline
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
GLP compliance:
yes (incl. QA statement)
Specific details on test material used for the study:
Batch: K41093666
Puritiy: 99.94 %
Oxygen conditions:
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure):
activated sludge, micro organisms from a domestic waste water treatment plant

- Origin
Municipal sewage treatment plant

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 centrifuged again. 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.
Duration of test (contact time):
28 d
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Parameter followed for biodegradation estimation:
test mat. analysis
Details on study design:
According to guideline
Reference substance:
Preliminary study:
The biodegradation in % was calculated based on the ThOD of the test item.
Test performance:
The reference item (Aniline) was sufficiently degraded to 60, 71.4, 73.2, and 73.5 % after an incubation for 7, 14, 21 and 28 days respectively.
The validity criterion that the degradation should be > 60 % after 14d was fulfilled.
% degradation (O2 consumption)
Sampling time:
28 d
% degradation (test mat. analysis)
Sampling time:
28 d
Validity criteria fulfilled:
Interpretation of results:
not readily biodegradable
The degradation rate of the test material did not reach 60 % within the 10-day window and after 28 days of incubation. Thus the test item is not readily biodegradable.
Executive summary:

The test item was investigated for its ready biodegradability in a Manometric Respirometry Test over a period of 28 days. The biodegradation was followed by the oxygen uptake of the micro organisms during exposure. The test material concentration was monitored by HPLC. As a reference item aniline was tested simultaneously under the same conditions as the test item, and functioned as a procedure control. The GLP study was performed according to OECD TG 301C.

The degradation rate of the test material did not reach 60 % within the 10 -day window and after 28 days of incubation. Thus the test item is not readily biodegradable.

Description of key information

The relevant study was performed according to GLP and the methods applied are fully compliant with OECD TG 301C. The test material was not readily biodegradable.

Key value for chemical safety assessment

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

Additional information