Pregna-4,6-diene-3,20-dione, 17-(acetyloxy)-6-chloro-1-(chloromethyl)-, (1.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:

Jul - Aug 1994

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted 1981

Deviations:

no

GLP compliance:

yes

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: aerated and stirred
- Preparation of inoculum for exposure: homogenized ans settled over 30 min

Duration of test (contact time):

28 d

Initial conc.:

10 mg/L

Based on:

test mat.

Initial conc.:

20 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: 30 mL of the inoculum from the activated sludge were added to the nutrient solutions in each of the test vessels. These mixtures were aerated with CO2-free air for about 24 hours to purge the system of carbon dioxide before test and reference compounds were added. CO2-free air was obtained by bubbling filtered air thraugh activated charcoal and soda lime pellets.
- Test temperature: 23 - 25 °C
- pH: 6.8 - 7.6
- pH adjusted: yes

TEST SYSTEM
- Number of culture flasks/concentration: 3
- 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(OHh 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(OHh with 0.05 N standardised HCI. Periodically (every day to 3 days within the first 10 days, and every 4 to 5 days within the rest of the test period), the CO2-absorber bottle nearest to the test boUles was removed for the titration. The remaining two absorbers were each moved one place closer to the test vessel, and a new absorber bottle filled with fresh Ba(OHh was placed at the far end of the series.

SAMPLING
- Sampling frequency: on day 3, 4,7, 11, 16 21, 25, 29
After the measurements of pH on day 28, 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 replicates
- Reference substance: yes, 1 replicate
- Abiotic sterile control: no
- Toxicity control: yes, 1 replicate

Reference substance:

acetic acid, sodium salt

Key result

Parameter:

% degradation (CO2 evolution)

Value:

1

Sampling time:

28 d

Results with reference substance:

The reference compound sodium acetate was degraded to more than a calculated 100%.

Table 1: Biological degradation (cumulative) in percent

Test	Nominal	Day of sampling
compound	concentration	3	4	7	11	16	21	25	29
Sodium acetate	20 mg/I	18	31	54	80	96	102	105	105
ZK 10882	10 mg/I	1	0	1	0	0	0	0	0
ZK 10882	20 mg/I	1	1	1	1	0	0	0	0

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

In accordance with the OECD guideline, the test product is not readily biodegradable under the conditions of the test.

Executive summary:

The test substance 6 -Chlor-Chlormethyldien was incubated in aqueous solution including nutrients with microorganisms from a municipal sewage treatment plant for 28 days (start of treatment = day 1). Additionally, a reference substance (sodium acetate) was tested according to the same procedure, in order to verify the viability and activity of the degrading micraorganisms. The test substance was incubated in two concentrations (10 mg/L and 20 mg/L suspension) and the reference substance in a concentration of 20 mg/L. Furthermore, one additional vessel without any test or reference substance was used as blank (control). The nutrient solutions were made up of phosphates, ammonium sulphate, magnesium sulphate, iron chloride, ammonium chloride and calcium chloride. The biological degradation of the test and reference substances was evaluated by measurement of the CO2 produced during the test period. CO2-production was determined on days 3, 4, 7, 11, 16, 21, 25 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 reference compound sodium acetate was degraded to more than a calculated 100%, the test compound was degraded to 1.0%. Accordingly, the test product is not readily biodegradable under the conditions of the test.

Description of key information

The test substance in not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater