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Biodegradation in water: screening tests

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Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
Mar 24, 2004 - May 21, 2004
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
GLP compliance:
yes (incl. certificate)
Specific details on test material used for the study:
Lot: L538792
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 re-suspended 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, corresponding to 1.5 g dry material per litre were mixed with test water.
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:
aniline
Preliminary study:
The biodegradation in % was calculated based on the ThOD of 3.394 mg 02/mg test item.
Test performance:
The reference item (Aniline) was sufficiently degraded to 61 % after 14 days and to 69% after 28 days of incubation.The validity criterion that the degradation should be > 60 % after 14 d 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 microorganisms 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 chemical analysis of the test material was perfomred 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% as found.

Biodegradation of aniline

The reference item was sufficiently degraded to 69 % after 14 days and to 75 % 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.

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
Apr 03 - May 31, 2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)
Qualifier:
according to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
GLP compliance:
yes
Specific details on test material used for the study:
Batch: E26001046


Oxygen conditions:
aerobic
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.:
102.4 mg/L
Based on:
test mat.
Initial conc.:
2.677 other: mg O2/mg test item
Based on:
ThOD
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
according to OECD TG 301 F
Reference substance:
benzoic acid, sodium salt
Key result
Parameter:
% degradation (O2 consumption)
Value:
3
Sampling time:
28 d
Details on results:
Points of degradation plot (test substance): 3% degradation after 28 d
Results with reference substance:
Points of degradation plot (reference substance): 87% degradation after 14 d, 90% degradation after 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 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.The GLP study was performed according to OECD TG 301F.

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 the degradation of max 3 % was found.

Biodegradation of Sodium Benzoate

The reference item was sufficiently degraded to a mean of 70 % after 4 days, and to a mean of 92 % after 28 days of incubation, thus confirming the suitability of the used activated sludge inoculum.

Biodegradation in the Toxicity Control

In the toxicity control containing both, the test item and the reference item, 34 % biodegradation was noted within 14 days and 35 % biodegradation was determined after 28 days of incubation. Thus, the test item can be assumed to be not inhibitory on the activated sludge micro organisms.

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 studies supplied were performed according to GLP and the methods applied are fully compliant with OECD TG 301C and 301F. No degradation was found in any of these studies.

Key value for chemical safety assessment

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

Additional information

Based on available data the test item must be regarded as not readily biodegradable.