17-acetoxy-1β,2β-methanopegna-4,6-diene-3,20-dione

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 Apr - 03 Sep 1998

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: activated sewage sludge from a municipal teatment plant (Kläranlage Berlin Ruhleben)
- Preparation of inoculum for exposure: effluent concentration in reaction mixture was 5 mL/L
- Pretreatment: the activated sludge was stirred and aerated for about 2 h, then homogenized and settled for 30 min.
- Water filtered: yes

Duration of test (contact time):

28 d

Initial conc.:

10 mg/L

Based on:

test mat.

Initial conc.:

20 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (CO2 evolution)

Value:

0

Sampling time:

28 d

Remarks on result:

other: nominal concentration: 20 mg/L

Parameter:

% degradation (CO2 evolution)

Value:

2

Sampling time:

28 d

Remarks on result:

other: nominal concentration: 10 mg/L

Results with reference substance:

The reference compound sodium acetate was degraded to more than 80%.

Validity criteria for the measurement of the biodegradation according to OECD 301:

Target condition according to guideline:	Actual condition according to the study:	Validity criteria met:
In order to check the procedure, reference compounds which meet the criteria for ready biodegradability are tested by setting up an appropriate vessel in parallel as part of normal test runs. Suitable compounds are aniline (freshly distilled), sodium acetate and sodium benzoate.	sodium acetate	Yes
A test is considered valid if the difference of extremes of replicate values of the removal of the test chemical at the plateau, at the end of the test or at the end of the 10-d window, as appropriate, is less than 20% and if the percentage degradation of the reference compound has reached the pass levels by day 14.	The % degradation of the two measured values of the test substance at the end of the test (28 d) range between 2 -5% There was 73% degradation of the reference substance after 28 d - the pass level (88 % for ThOD) was reached.	Yes
If in a toxicity test, containing both the test substance and a reference compound, less than 35% degradation (based on total DOC) or less than 25% (based on total ThOD or ThCO2) occurred within 14 days, the test substance can be assumed to be inhibitory. The test series should be repeated, using a lower concentration of test substance (if this can be done without seriously impairing the accuracy of the DOC determination) and/or a higher concentration of inoculum, but not greater than 30 mg solids/L.	The reference substance sodium acetate was degraded to more than 60% within 9 day. The CO2 produced in the blank control (35 mg) in the normal test period was within the limit set by the OECD guideline (50 mg). Hence, the quality criteria of the OECD guideline were fulfilled, i.e., the inoculum was viable and active.	Yes

 

Validity criteria fulfilled:

yes

Remarks:

See 'Any other information on results incl. tables'

Interpretation of results:

not readily biodegradable

Conclusions:

The reference compound sodium acetate was degraded to more than 80%, the test substance was degraded to 2% and 5%, respectively. The test substance is not readily biodegradable under the conditions of the test.

Executive summary:

The study was conducted to assess the biodegradation in water: ready biodegradability. The study was conducted in accordance with the OECD guideline 301 B. The reference compound sodium acetate was degraded to more than 80%, the test substance was degraded to 2% and 5%, respectively. The test substance is not readily biodegradable under the conditions of the test.

Description of key information

The study was conducted to assess the ready biodegradability. The study was conducted in accordance with the OECD guideline 301 B. The reference compound sodium acetate was degraded to more than 80%, the test substance was degraded to 2% and 5%, respectively. The test substance is not readily biodegradable under the conditions of the test.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater