Pregna-1,4,6-triene-3,20-dione, 17-hydroxy-

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 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

17-Hydroxy-1,4,6-pregnatriene-3,20-dione

EC Number:

613-906-1

Cas Number:

66212-25-7

Molecular formula:

C21 H26 O3

IUPAC Name:

17-Hydroxy-1,4,6-pregnatriene-3,20-dione

Test material form:

solid: bulk

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): Kläranlage Berlin Ruhleben
- Method of cultivation: homogenized aerated and stirred

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

10 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Test temperature: 23 - 24 °C
- pH: 7.5 - 7.8
- Continuous darkness: yes
- pH adjusted: yes

TEST SYSTEM
- Number of culture flasks/concentration: 3
- Method used to create aerobic conditions: Aerated with CO2-free air
- 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. On days 4, 6, 8, 11, 14, 19, 22, 2'7 and 29 the CO2 absorber bottle nearest to the test bottles was removed for the titration, with the exception of day 29 when all three bottles were removed. The remaining two absorbers were each moved one place closer to the test vessel and a new absorber bottle filled with fresh Ba(OH)2 was placed at the far end of the series. In cases where BaCO3 was also precipitated in the second absorber bottle of any solution, titrations of two Ba(OH)2 bottles were performed. Subsequently, two fresh absorbers were added.

SAMPLING
- Sampling frequency: 4, 6,8, 11, 14, 19, 22, 27, 29 days; After the measurements of pH, 1 mL of concentrated HCl was added to each test vessel in order to convert all dissolved inorganic carbon into CO2.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 3 vessels
- Abiotic sterile control: no
- Toxicity control: yes, 1 vessel
- Reference substance: yes, 1 vessel

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

82

Sampling time:

28 d

BOD5 / COD results

Results with reference substance:

The reference substance was completely degraded after 28 d.

Any other information on results incl. tables

Table 1: Amounts of CO2 produced (cumulative), in mg (values for ZK 5668, sodium acetate and toxicity control corrected for blank CO,: production)

		Day
		4	6	8	11	14	19	22	27	29
Control/blank (mean of 3 vessels)	Concentration of carbon	2,9	5	6,50	8,6	10,6	12,7	15,5	17,7	22,6
ZK 5668 (mean of 3 vessels)	0 mg/L	2,8	33	49,90	64	74,6	82,6	85,3	88,3	90,2
Reference (sodium acetate)	10 mg/L	42,5	65,7	75,00	85,5	93	99,5	101	103,8	105,3
Toxicity control (ZK 5668 + sodium acetate)	10 mg/L + 10 mg/L	39,8	92	117,90	141,7	157,9	170,3	176,1	181,7	185,2

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

According to the results of the test it can be concluded that the subsance is readily biodegradable under the conditions of the test.

Executive summary:

The purpose of this study was to determine the ready biodegradability of 1,4,6-Trienol (ZK 5668). The study was conducted in agreement with the OECD test guideline 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 1). The nutrient solutions were made up of phosphates, magnesium sulphate, iron chloride, ammonium chloride and calcium chloide. The test substance was incubated at 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/L (reference substance) plus test substance at 10 mg carbon/L representing a toxicity control. Furthermore, a blank control was tested in triplicate without any test or refeference 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 4, 6, 8, 11, 14, 19, 22, 27 and :29. On day 28 the solutions were acidified in order to expel all dissolved CO2 and CO2 was determined on day 29. The CO2 production was calculated as the percentage of total CO2 that the testmaterial could theoretically have produced, based on carbon content. The blank CO2 production was subtracted for correction.

The test compound 1,4,6 -Trienol was degraded to 68% on day 14 and 82% on day 29 (28 days of incubation). The reference compound sodium acetate was degraded to 60% on day 6 and 96% on day 29 (28 days of incubation). In the toxicity control, the reference compound (sodium acetate) plus the test compound, was degraded to 84% on day 29 (28 days of incubation), reflecting the degradation in the individual sets.

Based on the result, the substance is considered being readily biodegradable according to the OECD criteria.