3'H-Cycloprop[15,16]androsta-6,15-dien-17-one, 15,16-dihydro-3,5-dihydroxy-, (3.beta.,5.beta.,15.alpha.,16.alpha.)-

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

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Reference substance 001

Cas Number:

82543-15-5

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): sewage treatment plant "Kläranlage Berlin Ruhleben"
- Storage conditions: room temperature

Duration of test (contact time):

42 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
- Test temperature: 21 - 23°C
- pH: 7.4 -7.7
- pH adjusted: no
- Continuous darkness: yes
- Aeration: the test solutions were supplied with filtered CO2-free air (2.0 to 5.5 L air per hour for each test vessel)

TEST SYSTEM
- Test performed in closed vessels: yes
- 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: 3, 4, 7, 9, 14, 18, 23, 28, 30, 35, 42, 44

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

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

% Degradation 1

Key result

Parameter:

% degradation (CO2 evolution)

Value:

41

Sampling time:

28 d

% Degradation 2

Parameter:

% degradation (CO2 evolution)

Value:

48

Sampling time:

42 d

BOD5 / COD results

Results with reference substance:

100% after 28 d.

Any other information on results incl. tables

Biological degradation (cumulative) in percent (corrected for blank CO. production) of Endiol

Test Compound	Nominal Concentration of carbon	Day of sampling
		3	4	7	9	14	18	23	28	30	35	42	44
Endiol ( ZK 38700)	10 mg/L	4	12	12	12	16	26	35	41	43	44	46	48
Reference (sodium acetate)	10 mg/L	13	39	57	71	85	93	97	100	100	100	100	100
Toxicity control (ZK 38700 + sodium acetate)	10 mg/L + 10 mglL	7	23	32	38	46	50	57	63	65	67	69	71

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Conclusions:

In accordance with the OECD guideline, the test compound Endiol is not readily biodegradable under the conditions of the test and it was not toxic to the microbes of activated sludge. However, at the end of the test period, the test substance was partly degraded, probably indicating inherent biodegradability.

Executive summary:

The purpose of this study was to determine the ready biodegradability of Endiol (ZK 38700), which is an intermediate of the synthesis of drospirenone. The study was conducted in agreement with the OECD test guideline no. 301 B and the EC guideline. The test substance Endiol was incubated in a concentration of 10 mg carbon/L in triplicate. 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 10 mg carbon/I (reference substance) plus Endiol at 10 mg carbon/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 carbon dioxide (CO2) produced during the test period. CO2 production was determined on days 3, 4, 7, 9, 14, 18, 23, 28, 30, 35, 42 and 44. On day 43 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 Endiol was degraded to 48% at the end of the test on day 44 (42 days of incubation). The reference compound sodium acetate was degraded to 71% on day 9 (8 days of incubation) and up to 100% on day 28. In the toxicity control, the reference compound (sodium acetate) plus the test compound Endiol was degraded to 71 % on day 44 (42 days of incubation).The test compound Endiol is not readily biodegradable under the conditions of the test and it was not toxic to the microbes of activated sludge.