3β,21-dihydroxy-16α-methylpregn-5-en-20-one 21-acetate

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. 95 - Jan. 96

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:

1997

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:

3β,21-dihydroxy-16α-methylpregn-5-en-20-one 21-acetate

EC Number:

214-633-7

EC Name:

3β,21-dihydroxy-16α-methylpregn-5-en-20-one 21-acetate

Cas Number:

1173-09-7

Molecular formula:

C24H36O4

IUPAC Name:

2-[(1S,2R,3aS,3bS,7S,9aR,9bS,11aS)-7-hydroxy-2,9a,11a-trimethyl-1H,2H,3H,3aH,3bH,4H,6H,7H,8H,9H,9aH,9bH,10H,11H,11aH-cyclopenta[a]phenanthren-1-yl]-2-oxoethyl acetate

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): 16Alpha-Methyl-Acetoxypregnenolon
- Analytical purity: 97,3%
- Lot/batch No.: 14415018

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.:

11 mg/L

Based on:

DOC

Results and discussion

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

26

Sampling time:

28 d

Details on results:

The reference compound sodium acetate was degraded to 100% on day 29.
In the toxicity control, the reference compound (sodium acetate) plus the test compound
ZK 29211 was degraded to 59% on day 29, which was slightly lower than the degradation
expected on the basis of the results for the individual substances.
The substance was not toxic to the microbes of activated sludge .

Any other information on results incl. tables

Table1: Ready Biodegradability of test substance ZK-No. 29211 in comparison to the functional control and the toxicity control

Biodegradation (%)
	Days
	6	14	21	28
Test substance	4	13	20	26
Toxicity control	19	41	52	59
Functional control	54	77	90	100

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 29211 is not readily
biodegradable under the conditions of the test. However, at the end of the test period, the test
substance was partly degraded.

Executive summary:

The test substance 16Alpha-Methyl-Acetoxypregnenolon (ZK 29211) 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 11 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 micraorganisms. 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 test substance as 11 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 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 26% at the end of the test. The reference compound sodium acetate was degraded to 100% on day 29. The time required for 60% biodegradation of the reference compound was less than 8 days.

In the toxicity control, the reference compound (sodium acetate) plus the test compound

was degraded to 59% on day 29, which was slightly lower than the degradation expected on the basis of the results for the individual substances. However, this is considered to be a laboratory specific phenomenon and not due to toxic effects.