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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
Study period:
Study Plan Signed 21 January 1997 - Final Report emission 27 February 1997; Experimental Phase : 21 January 1997 to 19 February 1997.
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report date:
1997

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
GLP compliance:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
(E)-cyclohexadec-5-enone
Cas Number:
35951-24-7
Molecular formula:
C16H28O
IUPAC Name:
(E)-cyclohexadec-5-enone
Constituent 2
Chemical structure
Reference substance name:
(Z)-cyclohexadec-5-enone
Cas Number:
21944-95-6
Molecular formula:
C16H28O
IUPAC Name:
(Z)-cyclohexadec-5-enone
Specific details on test material used for the study:
Name (as stated in the report): Ambretone
Batch: 261997

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
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 resuspending in mineral medium) and kept aerobic until being used on the same day.
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
100 mg/L
Based on:
other: nominal test substance concentration
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Reference substance
Reference substance:
other: Sodium benzoate
Remarks:
99% purity

Results and discussion

% Degradation
Key result
Parameter:
% degradation (O2 consumption)
Value:
86
Sampling time:
28 d
Details on results:
Oxygen uptakes, as read on the SAPROMAT meters are corrected:
- by deducting the basic oxygen uptake of sludge blank samples (Flasks 2/3 and 2/4)
- proportionally to account for the differences between actual and nominal concentrations of test and reference substance

BOD5 / COD results

Results with reference substance:
Degradation of Sodium Benzoate exceeds 40% after 7 days and 65% after 14 days (observed 72% biodegradation on Day 7 and 83% on Day 14): the activity of the inoculum is thus verified and the test is considered valid.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
Ambretone undergoes 86% biodegradation after 28 days in the test conditions. Biodegradation starts (exceeds 10%) on day 3 (11% biodegradation) and reaches 72% at the end of the 10-day window (days 3 to 13).
Thus, Ambretone should be regarded as readily biodegradable according to this test.
The curves obtained with the reference substance alone and with Ambretone + reference substance show no toxic effect of Ambretone on the micro-organism at the test concentration.
Executive summary:

The Ready Biodegradability of Ambretone was determined by the Manometric Respirometry Test according to the OECD guideline 301F.

Ambretone undergoes 86% biodegradation after 28 days in the test conditions. Biodegradation starts (exceeds 10%) on day 3 (11%) and reaches 72% at the end of the 10-day window (days 3 to 13).

Thus, Ambretone should be regarded as readily biodegradable according to this test.

At the concentration used in the test (100 mg/L), Ambretone is not inhibitory to the micro-organisms.