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Environmental fate & pathways

Biodegradation in water: screening tests

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:
2009
Report Date:
2009

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)
Qualifier:
according to
Guideline:
EPA OPPTS 835.3110 (Ready Biodegradability)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
impurity
Specific details on test material used for the study:
Commercial name: Frutonile
Givaudan Code No.: 1461553
Chemical Nature: 2-Methyldecanenitrile
Empirical formula: C11H21N
Molecular weight: 167.3 g/mol
Aspect: colourless liquid
Lot No.: 9000738351 (analysis number TQT0800377)
Expiration date: December 26, 2010

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
Fresh activated sludge from a biological waste water treatment plant trating predominantly sewage (City of Geneva, Peney-Dessous) was used.
The sludge is collected in the morning, washed three times in the mineral medium (by centrifuging at 1000 g for 10 minutes, discarding the supernatant and and resuspending in mneral medium) and kept aerobic until being used on the same day.
Duration of test (contact time):
31 d
Initial test substance concentration
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

Test performance:
Oxygen updates, as read on the Oxitop controller, are corrected to acocunt for the small differences between actual and nominal concentrations of the test and reference substances.
Degradation of sodium benzoate exceeded 40% after 7 days and 65% after 14 days: the activity of the incolumn was thus verified (validility criterion).
The repeatability validility criterion (not more than 20% difference between replicates) is fulfilled. Therefore, the test is considered valid.
% Degradationopen allclose all
Key result
Parameter:
% degradation (O2 consumption)
Value:
74
Sampling time:
28 d
Parameter:
% degradation (O2 consumption)
Value:
76
Sampling time:
31 d
Parameter:
% degradation (O2 consumption)
Value:
10
Sampling time:
4 d
Parameter:
% degradation (O2 consumption)
Value:
54
Sampling time:
14 d

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The Ready Biodegradability of Frutonile was determined by the Manometric Respirometry Test.
The curves obtained with the reference substance alone and with Frutonile + reference substance show no toxicc effect of Frutonile to the micro-organisms at the test concentration (100 mg/l).
Frutonile undergoes 74% biodegradation after 28 days (76% after 31 days) in the test conditions.
The 10-day window criterion is not fullfilled (10% biodegradation on day 4 and 54% on day 14). Not meeting the 10 day window criterion shoulkd be attributed to the fact that the test substance contains nitrogen: The oxygen consumption observed is the addition of the oxygen consumption due to oxidation of carbon and hydrogen on one hand , and the oxidation of the nitrogen to nitrate by a difference bacterial species on the other hand (sequential oxidation). The 10-day window should therefore not be used as pass/fail criterion.
Thus, Frutonile should be regarded as readily biodegradable according to this test.