17H-Dicyclopropa[6,7:15,16]cyclopenta[a]phenanthren-17-one, octadecahydro-3,5-dihydroxy-10,13-dimethyl-, (3S,5R,6R,7R,8R,9S,10R,13S,14S,15S,16S)-

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Feb - Mar 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report date:

1999

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

No version available

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

3 beta,5-Dihydroxy-6 beta,7 beta;15 beta,16 beta-dimethylene-5 beta-androstan-17-one

EC Number:

617-347-4

Cas Number:

82543-16-6

Molecular formula:

C21 H30 O3

IUPAC Name:

3 beta,5-Dihydroxy-6 beta,7 beta;15 beta,16 beta-dimethylene-5 beta-androstan-17-one

Test material form:

solid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): The activated sewage sludge for the inoculum was collected on the day before the start of the experiment from a well-operated municipal sewage treatment plant ("Kläranlage Berlin-Ruhleben")
- Laboratory culture: stirred and aerated
- Storage conditions: room temperature

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

10 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Aeration of dilution water: the test solutions were supplied with filtered CO2-free air (2.5 to 6.0 L air per hour for each test vessel) for 30 d

TEST SYSTEM
- Number of culture flasks/concentration: 3
- Details of trap for CO2 and volatile organics if used: For the determination of the CO2 produced, three CO2 absorber bottles, filled with 100 mL 0.025 N Ba(OH)2 each, were connected in series to the exit air-pipe of each test bottle. The amount of CO2 produced was determined by titration of the remaining Ba(OH)2 with 0.05 N standardized HCI.

SAMPLING
- Sampling frequency: On day 3, 4, 7, 9, 14, 18, 23, 28 and 30
- Sampling method: On days 3, 4, 7, 9, 14, 18, 23, 28 and 30 the CO2 absorber bottle nearest to the test bottles was removed for the titration, with the exception of day 30 when all three bottles of the test substance vessels and the toxicity control were removed. The remaining two absorbers were each moved one place closer to the test vessel and a new absorber bottle filled with fresh Ba(OH)2 was placed at the far end of the series. In cases where BaC03 was also precipitated in the second absorber bottle of any solution, titrations of two Ba(OH)2 bottles were performed. Subsequently, two fresh absorbers were added.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 3 vessels
- Toxicity control: yes, 1 vessel
- Reference substance: yes, 1 vessel

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

3

Sampling time:

30 d

Details on results:

In the toxicity control, the reference compound (sodium acetate) plus the test compound was degraded to 52% on day 30 (28 days of incubation).

BOD5 / COD results

Results with reference substance:

The reference compound sodium acetate was degraded to 71% on day 9 (8 days of incubation) and up to 100% on day 28.

Any other information on results incl. tables

The CO2 produced by the blank control (20.1 mg/L) was within the limit set by the OECD guideline (40 mg/L). The criteria set by the OECD guideline require that the reference substance is degraded to 60% or more within 14 days after start of incubation. The reference substance sodium acetate was degraded to 71 % within 8 days of incubation. Hence, the yalidity criteria of the OECD guideline were fulfilled, i.e. the inoculum was viable and active.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

In accordance with the OECD guideline, the test compound Dimethylenketon is not readily biodegradable
under the conditions of the test and it was not toxic to the microbes of activated sludge.

Executive summary:

The purpose of this study was to determine the ready biodegradability of Dimethylenketon (ZK 34517). The study was conducted in agreement with the OECD test guideline no.301 B and the EC guideline. The test substance Dimethylenketon was incubated in an aqueous solution including nutrients with microorganisms from a municipal sewage treatment plant for 28 days (start of treatment =day 1).

The test substance was incubated in a concentration of 10 mg carbon/L in triplicate. The biological degradation of the test and reference substances was evaluated by measurement of the carbon dioxide (C02) produced during the test period.

The test compound Dimethylenketon was degraded to 3% on day 30 (28 days of incubation). In accordance with the OECD guideline, the test compound ZK 34517 is not readily biodegradable under the conditions of the test and it was not toxic to the microbes of activated sludge.