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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:
2014
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Version / remarks:
Adopted 1992-07-17
GLP compliance:
yes
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: STO2697671
- Expiration date of the lot/batch: 2013-12-31
-
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Datanasha Sewage Treatment Plant of Guangzhou
- Preparation of inoculum for exposure: washed by centrifugation, resuspended in mineral medium
- Concentration of sludge: 2.4 g dry material per liter
Duration of test (contact time):
28 d
Initial conc.:
33 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Test temperature: 22.1 - 22.7°C
- pH: 7.49 - 7.51
- Continuous darkness: yes

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 bottles
- Toxicity control: 1 bottle
- Other:

Reference substance:
benzoic acid, sodium salt
Key result
Parameter:
% degradation (O2 consumption)
Value:
69.3
Sampling time:
28 d
Parameter:
% degradation (O2 consumption)
Value:
46.5
Sampling time:
14 d
Details on results:
Reference substance (14d): 88 % degradation (O2 consumption)
Toxicity control (14d): 55.8 % degradation (O2 consumption)
Test substance (14d): 48.5 % and 44.5 % degradation (O2 consumption)
Test substance 28d): 72.3 % and 66.2 % degradation (O2 consumption)
Parameter:
COD
Value:
1 680 mg O2/g test mat.
Results with reference substance:
Reference substance (14d): 88 % degradation (O2 consumption)
Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable, but failing 10-day window
Conclusions:
The percentage biodegradation of the test substance did not reach 60 % within the 10d-window of the test under the conditions of the study. However, 69.3 % degradation was reached at day 28.

Description of key information

The percentage biodegradation of the test substance did not reached 60 % at the 10d-window of the test under the conditions of the study. However, 69.3 % degradation was reached at day 28.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable but failing 10-day window

Additional information