(±)-13-ethyl-3-methoxygona-1,3,5(10),8-tetraen-17-one

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:

Jun - Jul 1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: According to OECD guideline under GLP

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

Not relevant

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

(±)-13-ethyl-3-methoxygona-1,3,5(10),8-tetraen-17-one

EC Number:

227-699-7

EC Name:

(±)-13-ethyl-3-methoxygona-1,3,5(10),8-tetraen-17-one

Cas Number:

5941-92-4

Molecular formula:

C20H24O2

IUPAC Name:

13-ethyl-3-methoxy-6,7,11,12,13,14,15,16-octahydro-17H-cyclopenta[a]phenanthren-17-one (non-preferred name)

Details on test material:

- Name of test material (as cited in study report): Ethyltetraenon
- Analytical purity: 95.9%
- Lot/batch No.: 1114001

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

10 mg/L

Based on:

DOC

Results and discussion

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

6

Sampling time:

28 d

Details on results:

The test compound was degraded to 6% on day 30 (8: 28 days of incubation).
The reference compound sodium acetate was degraded to 70% on day 10 (9 days of incubation) and up to 90% on day 30.
In the toxicity control, the reference compound (sodium acetate) plus the test compound was degraded to 45% on day 30.

Any other information on results incl. tables

Table 1: Biological degradation (cumulative) in percent (corrected for blank C02 production) of ZK 47568

Test	Nominal	Day of sampling
compound	concentration of carbon	3	4	7	10	14	18	24	28	30
ZK 47568	10 mg/I	1	1	1	1	1	2	3	3	6
Sodium acetate (reference)	10 mg/I	14	34	58	70	77	81	85	87	90
ZK 47568 + sodium acetate (toxicity control)	10 mg/I +	8	19	31	38	41	43	44	45	45
	10 mg/I

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not inherently biodegradable

Conclusions:

The test compound ZK 47568 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 Ethylteraenon (ZK 47568). The study was conducted in agreement with the OECD guideline for testing of chemieals, Ready biodegradability: C02-evolution test, no. 301 B.

The test substance ZK 47568 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 nutrient solutions were made up of phosphates, magnesium sulphate, iron chloride, ammonium chloride and calcium chloride. The test substance was incubated in a concentration of 10 mg carbon/L in triplicate. Additionally, a reference substance (sodium acetate) was tested according to the same procedure, in order to verify the viability and activity of the degrading microorganisms. Furthermore, a blank control was tested in triplicate without any test or reference substance. One further set was incubated with sodium acetate as 10 mg carbon/L (reference substance) plus ZK 47568 as 10 mg carbon/L representing a toxicity control. The biological degradation of the test and reference substances was evaluated by measurement of the carbon dioxide (C02) produced during the test period. CO2 production was determined on days 3, 4, 7, 10, 14, 18, 24 and 28. On day 29 the solutions were acidified in order to expel all dissolved CO2 and CO2 was determined on day 30. The CO2 production was calculated as the percentage of total CO2 that the test material could theoretically have produced, based on carbon content. The blank CO2 production was subtracted for correction.

The test compound was degraded to 6% on day 30 (8: 28 days of incubation). The reference compound sodium acetate was degraded to 70% on day 10 (9 days of incubation) and up to 90% on day 30. In the toxicity control, the reference compound (sodium acetate) plus the test compound was degraded to 45% on day 30.