1-(5-ethyl-5-methylcyclohex-1-en-1-yl)pent-4-en-1-one

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:

29-01-2016 to 14-04-2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study performed under GLP. All relevant validity criteria were met.

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

inspected: September 2013; signature: December 2013

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): A mixed population of activated sewage sludge micro-organisms (Test System) was obtained from the secondary treatment stage of the sewage treatment plant at Villette (Geneva, Switzerland)), which treats predominantly domestic sewage.
- Laboratory culture: See source of inoculum/activated sludge.
- Method of cultivation: The sample of activated sewage sludge was maintained on continuous aeration upon receipt.
- Storage conditions: See pretreatment field.
- Storage length: < 1 week
- Preparation of inoculum for exposure: See pre-treatment field.
- Pretreatment: The sample of activated sewage sludge was maintained on continuous aeration upon receipt. A sample of the activated sewage sludge was washed three times by settlement (centrifuge) and suspension in culture medium. To remove any excessive amounts of Dissolved Organic Carbon (DOC) that may have been present, the solution was stirred and maintained on with pure oxygen at room temperature. Determination of dry weight is made to inoculate final solution with 30mg/L dry weight activated sludge.
- Concentration of sludge: The sludge was diluted in the BOD bottles to 30 mg DW/L.
- Initial cell/biomass concentration: Not applicable.
- Water filtered: Not applicable. Culture medium was in accordance with OECD TG 301F.
- Type and size of filter used, if any: Not applicable.

Duration of test (contact time):

28 d

Initial conc.:

100.5 mg/L

Based on:

other: Test item (test 1)

Initial conc.:

99.95 mg/L

Based on:

other: Test item (test 2)

Initial conc.:

100.2 mg/L

Based on:

other: Test item (test 3)

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: See table 1. 10 mL of Solution A [KH2PO4: 8.50 g/L; K2HPO4: 21.75g/L; Na2HPO4,2H2O: 33.40 g/L; NH4Cl: 0.50 g/L]; 1 mL of Solution B [CaCl2,2H2O: 36.40 g/L]; 1 mL of Solution C [MgSO4,7H2O: 22.50 g/L]; 1 mL of Solution D [FeCl3,6H2O: 0.25 g/L] and purified water diluted to 1 L.
- Solubilising agent (type and concentration if used): None.
- Test temperature: 22 ±1 °C
- pH: See table 1.
- pH adjusted: No. (final pH was in the range of 7.30 to 7.70 for test item vessels)
- CEC (meq/100 g): Not reported.
- Aeration of dilution water: Not reported
- Suspended solids concentration: 30 mg/L dry weight
- Continuous darkness: No. The test was conducted in diffuse light.

TEST SYSTEM
- Culturing apparatus: 1000mL glass flasks with continuous stirring (fill volume ca. 200 mL)
- Number of culture flasks/concentration: In triplicate (test item); In duplicate (Inoculum blank); single flasks (Abiotic Sterile Control and toxicity control)
- Method used to create aerobic conditions: Sealed flasks with sensor head/CO2 trap.
- Method used to create anaerobic conditions: Not applicable.
- Measuring equipment: The respirometer used during this study is an Oxitop Control System (WTW oxitopC). Evolved carbon dioxide is absorbed by the CO2 trap.
- Test performed in closed vessels due to significant volatility of test substance: Not reported.
- Test performed in open system: No.
- Details of trap for CO2 and volatile organics if used: See above.

SAMPLING
- Sampling frequency: Daily.
- Sampling method: The respirometer used during this study is an Oxitop Control System.
- Sterility check if applicable: Not reported.
- Sample storage before analysis: Not applicable.

CONTROL AND BLANK SYSTEM
- Inoculum blank: Yes. See table 1.
- Abiotic sterile control: Yes.
- Toxicity control: Yes.
- Other: Positive reference control (Sodium Benzoate).

Reference substance:

benzoic acid, sodium salt

Remarks:

99.80 mg/L

Test performance:

1. The repeatability validity criterion (not more than 20% difference between replicates) is fulfilled for the flasks containing test item at end of 10-day window and on day 28. Therefore, the test is considered valid.
2. The BOD of the inoculated blank control was 43.4 mgO2/L and 31.0 mgO2/L and < 60 mgO2/L after 28 days
3. The pH at day 28 was in the range of 6.0 to 8.5 (actual 7.34 to 7.37 for test item vessels)
4. The toxicity test attained 29% degradation at 14 days and 49% degradation after 28 days thereby confirming that the test material was not toxic to the sewage treatment microorganisms used in the study.
5. Sodium Benzoate attained 84% degradation at 14 days and 90% degradation after 28 days thereby confirming the suitability of the inoculum and test conditions.

Parameter:

% degradation (O2 consumption)

Value:

23

Sampling time:

28 d

Remarks on result:

other: test 1; 10-day window not met

Parameter:

% degradation (O2 consumption)

Value:

25

Sampling time:

28 d

Remarks on result:

other: test 2 ; 10-day window not met

Parameter:

% degradation (O2 consumption)

Value:

21

Sampling time:

28 d

Remarks on result:

other: test 3 ; 10-day window not met

Details on results:

The 10-day window criteria was not met in all replicates.

Results with reference substance:

Sodium Benzoate attained 84% degradation after 14 days thereby confirming the suitability of the inoculum and test conditions.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The mean biodegradation in triplicate was 23% at day 28. The 10-day window criteria was not met.

Executive summary:

The ready biodegradability test was carried out according to OECD TG 301F guideline under GLP. The test item, at a concentration of 100.5 mg/L in test 1, at a concentration of 99.95 mg/L in test 2 and at a concentration of 100.20 mg/L in test 3 was exposed to activated sewage sludge micro-organisms obtained from the secondary treatment stage of the sewage treatment which treats predominantly domestic sewage (Villette: Geneva, Switzerland) with culture medium in sealed culture vessels in diffused light at 22°C ± 1°C for 28 days. The sludge was diluted in the BOD bottles to 30 mg DW/L. The degradation of the test item was assessed by the measurement of daily oxygen consumption on days 0 and 28 using an Oxitop control system. Control solutions with inoculum and the reference substance, sodium benzoate, together with a toxicity control were used for validation purposes. In the test inoculum blank the oxygen uptake was < 45 mg O2/L. The pH value at the end of the test period 28 days did not exceed 7.34 in the test item systems and 7.70 in the reference item system. The test system met the validation criteria of the guideline. The toxicity test attained 29% degradation after 14 days thereby confirming that the test item was not inhibitory to the sewage treatment micro-organisms used in the study. Sodium Benzoate attained 84% degradation after 14 days thereby confirming the suitability of the inoculum and test conditions. The mean biodegradation for triplicate test flasks at 28 days for the test item was 23% and the 10-day window was not met. Under the conditions of the study, test item is not considered as readily biodegradable.

Description of key information

Biodegradation: not readily biodegradable, mean biodegradation 23 % (28-days; 10-day window not met), OECD TG 301F, 2016

Additional information

Key Study : OECD TG 301F, 2016 : The ready biodegradability test was carried out according to OECD TG 301F guideline under GLP. The test item, at a concentration of 100.5 mg/L in test 1, at a concentration of 99.95 mg/L in test 2 and at a concentration of 100.20 mg/L in test 3 was exposed to activated sewage sludge micro-organisms obtained from the secondary treatment stage of the sewage treatment which treats predominantly domestic sewage (Villette: Geneva, Switzerland) with culture medium in sealed culture vessels in diffused light at 22°C ± 1°C for 28 days. The sludge was diluted in the BOD bottles to 30 mg DW/L. The degradation of the test item was assessed by the measurement of daily oxygen consumption on days 0 and 28 using an Oxitop control system. Control solutions with inoculum and the reference substance, sodium benzoate, together with a toxicity control were used for validation purposes. In the test inoculum blank the oxygen uptake was < 45 mg O2/L. The pH value at the end of the test period 28 days did not exceed 7.34 in the test item systems and 7.70 in the reference item system. The test system met the validation criteria of the guideline. The toxicity test attained 29% degradation after 14 days thereby confirming that the test item was not inhibitory to the sewage treatment micro-organisms used in the study. Sodium Benzoate attained 84% degradation after 14 days thereby confirming the suitability of the inoculum and test conditions. The mean biodegradation for triplicate test flasks at 28 days for the test item was 23% and the 10-day window was not met. Under the conditions of the study, test item is not considered as readily biodegradable.