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Environmental fate & pathways

Biodegradation in water: screening tests

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Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Qualifier:
according to
Guideline:
EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
Activated sludge from a biologic sewage treatment plant was used. The chosen plant is treating mostly household sewage.
The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant, Im Altenschemel, NW-Lachen-Speyerdorf.
Date of collection: 10. May 2017, batch no: 20170510.
The sludge was filtrated, washed with tap water 2x, then washed with and re-suspended in test medium. It was then aerated.
The dry matter was determined as 3800 mg suspended solids/L.
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
37 mg/L
Based on:
ThOD
Remarks:
(corresponding to 100.4 mg/L ThOD)
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

% Degradationopen allclose all
Key result
Parameter:
% degradation (O2 consumption)
Value:
46
Sampling time:
10 d
Key result
Parameter:
% degradation (O2 consumption)
Value:
48
Sampling time:
28 d

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
Oxygen consumption in the blank controls and in the positive controls was normal, indicating that the test system has worked properly.
The degree of biodegradation reached 48 % after 28 days. The 10-day-window began on day 6, at its end (day 16), 46 % were reached, staying below the pass level of 60% given in the OECD guideline. Therefore, when applying the 10-day-window, the test item Estragole is not readily biodegradable.