13-ethyl-11-methylene-gon-4-ene-3,17-dione

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:

10 Jun 2020 - 09 July 2020

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Adopted, July 17, 1992

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

(3aS,3bS,9aR,9bS,11aS)‐11a‐ethyl‐10‐methylidene‐1H,2H,3H,3aH,3bH,4H,5H,7H,8H,9H,9aH,9bH,10H,11H,11aH‐cyclopenta[a]phenanthrene‐1,7‐dione

Cas Number:

54024-17-8

Molecular formula:

C20 H26 O2

IUPAC Name:

(3aS,3bS,9aR,9bS,11aS)‐11a‐ethyl‐10‐methylidene‐1H,2H,3H,3aH,3bH,4H,5H,7H,8H,9H,9aH,9bH,10H,11H,11aH‐cyclopenta[a]phenanthrene‐1,7‐dione

Test material form:

solid: particulate/powder

Details on test material:

Storage Conditions: In refrigerator (2-8°C)

Specific details on test material used for the study:

Physical Description: Off-white powder
Storage conditions: In refrigerator (2-8°C)
Test item handling: No specific handling conditions required

Study design

Oxygen conditions:

anaerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source: The source of test organisms was activated sludge freshly obtained from a municipal
sewage treatment plant: 'Waterschap Aa en Maas', 's-Hertogenbosch, The Netherlands, receiving predominantly domestic sewage.
- Treatment: The freshly obtained sludge was kept under continuous aeration until further treatment. Before use, the sludge was coarsely sieved (1 mm). After treatment, the concentration of suspended solids (SS) was determined to be 3 g/L in the concentrated sludge as used for the test. The sludge was used as inoculum at a concentration of 10 mL per liter of mineral medium, leading to a final concentration SS of approximately 30 mg/L.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

80 mg/L

Based on:

ThOD

Initial test substance concentration 2

Initial conc.:

29 mg/L

Based on:

test mat.

Details on study design:

TEST CONDITIONS

- Test vessels: 500 mL amber glass bottles. The end volume of medium was 244 mL, in order to obtain the required headspace-to volume ratio.
- Milli-RO water Tap-water purified by reverse osmosis (Milli-RO) and subsequently passed over activated carbon.
- CO2 absorber: Soda lime pellets (Merck, Darmstadt, Germany).
- Illumination: The test media were incubated in the dark.
- Suspended solid concentration: approximately 30 mg/L.
- Stock solution Mineral medium
A) 8.50 g KH2PO4: 21.75 g K2HPO4; 67.20 g Na2HPO4.12H2O; 0.50 g NH4Cl dissolved in Milli-RO water and made up to 1 L, pH 7.4 ± 0.2
B) 22.50 g MgSO4.7H2O dissolved in Milli-RO water and made up to 1 L.
C) 36.40 g CaCl2.2H2O dissolved in Milli-RO water and made up to 1 L.
D) 0.25 g FeCl3.6H2O dissolved in Milli-RO water and made up to 1 L.
_ Mineral medium 1 L mineral medium contains: 10 mL of solution (A), 1 mL of solutions (B) through (D) and Milli-RO water.
- Test temperature: Continuously measured in a vessel with Milli-RO water in the same climate-controlled incubator. The measure temperature was between 22 and 23°C
- pH: The pH was measured at the start and at the end of the test period. The pH at the start of the test was 7.4 and varied between 7.4 and 8.2 at the end of the test.

TEST DESIGN
- Test suspension: containing test item and inoculum (2 bottles).
- Inoculum blank: containing only inoculum (2 bottles)
- Procedural control: containing procedural control item and inoculum (1 bottle).
- Toxicity control: containing inoculum, test item and procedural control item in amounts contributing equally to the total ThOD (1 bottle).
- Test vessel preparation: At the start of the test (Day 0), test and/or procedural control item were added to the respective bottles. The volumes of suspensions were made up to 244 mL using inoculated mineral medium. Rubber gaskets containing an appropriate amount of CO2 absorber were inserted into each bottle. Subsequently, each bottle was sealed by screwing an automated respirometer head on top.
- Measuring equipment: Lovibond BD600-GLP manometric respirometry system, equipped with an inductive stirring system.
- Measurements: Oxygen consumption measurements were recorded automatically for 28 days

Reference substance

Reference substance:

other: Sodium acetate

Results and discussion

Test performance:

The relative biodegradation values calculated from the measurements performed during the
test period revealed no biologically relevant biodegradation of EMETAM by the end of the
test, based on ThOD (0 % and 1 % for bottle A and B, respectively).
In the toxicity control, more than 25 % biodegradation occurred within 14 days (44%, based
on ThOD). Therefore, the test item was considered not to inhibit microbial activity.
Functioning of the test system was checked by testing the procedural control item sodium
acetate, which showed a normal biodegradation curve.

% Degradation

% Degradation 1

Key result

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

28 d

Remarks on result:

other: Based on ThOD

% Degradation 2

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Remarks on result:

other: Based on ThOD

BOD5 / COD results

Results with reference substance:

. The procedural control item (reference substance) was biodegraded by at least 78 % within 14 days.

Any other information on results incl. tables

 

pH valuea of different test media

Test medium	Day 0	Day 28
Blank Control (A)	7.5	7.4
Blank Control (B)	7.5	7.4
Procedural Control	7.5	8.2
Emetam (A)	7.5	7.4
Emetam (B)	7.5	7.4
Toxicity Control	7.5	8.1

 

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

For detail see "Overall Remarks, Attachment"

Interpretation of results:

not readily biodegradable

Conclusions:

In conclusion, EMETAM was not readily biodegradable under the conditions of the Manometric Respirometry Test.

Executive summary:

In a manometric Respirometry test performed according to OECD guideline 301F and GLP principles, EMETAM was evaluated for its ready biodegradability. The test was performed in an aerobic aqueos medium containing activated sludge over a period of 28 days. The test item was tested in duplicate at a concentration of 29 mg/L, corresponding to a ThOD of 80 mg O₂/L. The relative biodegradation values calculated from the measurements performed during the test period revealed no biological relevant biodegradation of EMETAM by the end of the test, based on ThOD (0% and 1% for bottle A and B, respectively). In the toxicity control 44% biodegradation occurred within 14 days, based on ThOD. Therefore, the test item was considered not to inhibit microbial activity. In conclusion, EMETAM was not readily biodegradable under the conditions of the Manometric respirometry test.

All validity criteria were met, the study is considered valid.