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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Sep 28, 2005 - Nov 28, 2005
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Oxygen conditions:
aerobic
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
- OriginMunicipal sewage treatment plant-Conditioning: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
Details on study design:
According to guideline
Reference substance:
aniline
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 55%, 61%, 62%, and 62 % after an incubation for 7, 14, 21 and 28 days respectively.The validity criterion that the degradation should be > 60 % after 14d was fulfilled.
Key result
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
28 d
Key result
Parameter:
% degradation (test mat. analysis)
Value:
0
Sampling time:
28 d
Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
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:

Purpose

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. 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 analytical monitoring of the test material concentration during the course of this study was performed using HPLC.

Result

Biodegradation of test item

After correction of the mean biochemical oxygen demand of the inoculum controls at the end of the 28 -day exposure period a degradation of 0%(oxgen consumption) and 0% (HPLC analysis) as found.

Biodegradation of aniline

The reference item was sufficiently degraded to 66 % after 14 days and to 70.2 % after 28 days of incubation, thus confirming the suitability of the used activated sludge inoculum.

Conclusion

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 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.

Key value for chemical safety assessment

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

Additional information

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. 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 analytical monitoring of the test material concentration during the course of this study was performed using HPLC.

Biodegradation of test item

After correction of the mean biochemical oxygen demand of the inoculum controls at the end of the 28 -day exposure period a degradation of 0%(oxgen consumption) and 0% (HPLC analysis) as found.

Biodegradation of aniline

The reference item was sufficiently degraded to 66 % after 14 days and to 70.2 % after 28 days of incubation, thus confirming the suitability of the used activated sludge inoculum.

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.