19-Norpregn-5(10)-ene-21-nitrile, 17-hydroxy-3-oxo-, (17.alpha.)-

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:

Jan - Feb 2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Deviations:

no

Principles of method if other than guideline:

not relevant

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Duration of test (contact time):

28 d

Initial conc.:

200 mg/L

Based on:

ThOD/L

Parameter:

% degradation (O2 consumption)

Value:

0.9

Sampling time:

28 d

Details on results:

The reference compound sodium acetate was degraded to 83% . 60% degradation was reached on day 6.
In the toxicity control, the reference compound (sodium acetate) plus the test compound ZK 37877, was degraded to 45% on day 29.

Table 1: Biological degradation in percent (corrected for blank O2 consumption) of ZK 37877 (selected timepoints)

		Day ofsampling (selected time points)
Test compound	Concentration expressed in theoretical O2 demand	2	6	10	14	18	22	26	29
ZK 37877	200 mg/L	0,2	0	0	0,4	0,5	0,7	0,7	0,9
Reference (sodium acetate)	200 mg/L	21,1	60,2	75,4	79,4	80,8	82,8	82,2	83,2
Toxicity control (ZK 37877 + sodium acetate)	100 mg/L+ 100 mg/L	19,1	40,4	43,3	44,2	44,9	44,9	45,1	45,3

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

In accordance with the OECD 301F, the test compound ZK 37877 is not readily biodegradable under the conditions ofthe 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 5 -Dehydrocyanomethylketon (ZK 37877), which is an intermediate of the synthesis of Dienogest, in the manometric respiration test. The study was conducted in agreement with the OECD test guideline no. 301F.

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 1). The nutrient solutions were made up of phosphates, magnesium sulphate, iron chloride, ammonium chloride and calcium chloride. The test substance was incubated at a concentration of 200 mg theoretical oxygen demand (ThOD) per litre. Additionally, a reference substance (sodium acetate) was tested in a single set according to the same procedure, in order to verify the viability and activity of the degrading microorganisms. One further set was incubated with sodium acetate at 100 mg ThOD/L (reference substance) plus ZK 37877 at 100 mg ThOD/L representing a toxicity control. Furthermore, a blank control was tested in triplicate without any test or reference substance. The biological degradation of the test and reference substances was evaluated by measurement of the O2 consumption during the test period. O2 consumption was continuously monitored and recorded by an automated device. The O2 consumption was calculated as the percentage of total O2 that the test material could theoretically have consumed, based on the molecular formula. The blank O2 consumption was subtracted for correction.

The test compound was degraded to 0.9% on day 29 (28 days of incubation). The reference compound sodium acetate was degraded to 83% on day 29 (28 days of incubation). 60% degradation was reached on day 6. In the toxicity control, the reference compound (sodium acetate) plus the test compound ZK 37877, was degraded to 45% on day 29 (28 days ofincubation) which reflected the degradation in the individual sets.

Description of key information

In accordance with the OECD 301F, the test compound ZK 37877 is not readily biodegradable under the conditions ofthe test and it was not toxic to the microbes of activated sludge.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater