1,3-Cyclopentanedione, 2-[(2E)-2-(3,4-dihydro-6-methoxy-1(2H)-naphthalenylidene)ethyl]-2-ethyl-

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:

Dec 1995 - Jan 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:

1997

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:

3-Methoxy-18-methyl-8,14-seco-1,3,5(10),9(11)-estratetraene-14,17-dione

EC Number:

613-005-3

Cas Number:

62298-52-6

Molecular formula:

C20H24O3

IUPAC Name:

3-Methoxy-18-methyl-8,14-seco-1,3,5(10),9(11)-estratetraene-14,17-dione

Details on test material:

- Name of test material (as cited in study report): 17-Keto-Ethyl-Seco-Verbindung
- Analytical purity: 98.8
- Lot/batch No.: 10037206

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

12 mg/L

Based on:

DOC

Results and discussion

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

10

Sampling time:

28 d

Details on results:

The reference compound sodium acetate was degraded to 100% on day 29. The time required for 60% biodegradation of the reference compoundwasless than 8 days. In the toxicity control, the reference compound (sodium acetate) plus the test compound ZK 46073 was degraded to 42% on day 29.

Any other information on results incl. tables

Table 1: Biological degradation (cumulative) in percent of ZK 46073 (corrected for blank C02 production)

Test	Nominal	Day of sampling
compound	concentration of carbon	1	3	6	8	10	14	17	21	24	28	29
ZK 46073	12 mg/L	1	1	1	1	3	3	7	8	9	10	10
Sodium acetate (reference)	10 mg/L	1	25	54	66	72	77	87	90	94	99	100
ZK 46073 + sodium acetate (toxicity control)	12 mg/L + 10 mg/L	1	10	19	25	30	34	37	37	38	39	42

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Conclusions:

In accordance with the OECD guideline, the test compound ZK 46073 is not readily
biodegradable under the conditions of the test. The substance was not toxic to the microbes of
activated sludge.

Executive summary:

The purpose of this study was to determine the ready biodegradability of 17 -Keto-Ethyl-Seco-Verbindung (ZK 46073). The study was conducted in agreement with the test guideline OECD guideline for testing of chemicals, Ready biodegradability: C02-evolution test, no. 301 B.

The test substance was incubated in an aqueous solution including nutrients with microorganisms from a municipal sewage treatment plant for 28 days (start of treatment = day 0). 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 12 mg carbon/L in duplicate. Additionally, one set with the reference substance (sodium acetate) was incubated in a concentration of 10 mg carbon/L and tested according to the same procedure, in order to verify the viability and activity of the degrading micro-organisms. Furthermore, a blank control was tested in duplicate without any test or reference substance. One further set was incubated with sodium acetate as 10 mg carbon/L (reference substance) plus ZK 46073 as 12 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 1, 3, 6, 8, 10, 14, 17, 21, 24, 28 and 29 and 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 ZK 46073 was degraded to 10% at the end of the test. The reference compound sodium acetate was degraded to 100% on day 29. The time required tor 60% biodegradation of the reference compound was less than 8 days. In the toxicity contral, the reference compound (sodium acetate) plus the test compound was degraded to 42% on day 29. The degradation in the toxicity control was slightly lower than the degradation of the respective individual substances. The lower degradation noted in the toxicity control compared to the reference substance is considered to be a laboratory-specific phenomenon and not due to toxic effects.