5,6,7-TRIMETHYLOCTA-2,5-DIEN-4-ONE

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

From 8 December 2003 to 12 February 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Commercial name: GR-85-2517
Apect: pale yellow liquid
Expiration date: September 12, 2004

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Fresh activated sludge from a biological waste water treatment plant treating predominantly domestic sewage (city of Geneva, Peney-Dessous) was used.

The sludge is collected in the morning, washed three times in the mineral medium (by centrifuging at 1000g for 10 minutes, discarding the supernatant and resuspending in mineral medium) and kept aerobic until being used on the same day.

Duration of test (contact time):

34 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Test conditions:
- composition of medium:
Nutrient stock solutions
Solution A: KH2PO4 : 8.5g; K2HPO4 : 21.75g; Na2HP04.2H20: 33.4g and NH4CI : 0.5g; Dissolved water and made up to 1 litre.
Solution B: CaCl2 27.5g dissolved and made up to 1 litre
Solution C: MgSO4.7H2O 22.5g dissolved in water and made up to 1 litre.
Solution D: FeCl3, 6H2O: 0.25g; HCl conc. one drop dissolved in water and made up to 1 litre

The medium is prepared by mixing 50 ml of solution A and 2000 ml deionised water, adding 5 ml of each of the solution B, C and D and making up to 5 litres with deionised water. The pH is measured and if necessary adjusted to 7.4 +/- 0.2 with phosphoric acid or potassium hydroxide.


Preparation of the flasks :
Test substance samples (25 mg, corresponding to 100 mg/l in a 250-ml flask) are weighed in small aluminium boats and added directly to the test flasks of the SAPROMAT, whereas reference substance samples (sodium benzoate) are added as 1.0 ml of a 25 mg/ml solution in mineral medium.
All flasks are filled with 250 ml of mineral medium. Samples of test or reference substance, or both, are added. Then, a volume of suspended sludge corresponding to 7.5 mg dry weight (generally 1 to 3 ml) is added. Except when the test substance has an acid or alkaline character, the pH of each flask is not measured but assumed to be the same as the mineral medium, in order not to remove any floating undissolved test substance from the test medium by dipping a glass electrode in it. Neutral test substances, even sodium benzoate, were shown not to affect the pH of the medium by more than 0.1 pH unit. About 2 g of soda lime is placed in an attachment of the stopper, the flasks are closed and placed in the water bath of the SAPROMAT. After temperature and pressure equilibration, the oxygen meters of the instrument are set to zero (time zero of the experiment).

- Activated sludge
Dry weight of suspended solids: 3.30 g/L
To obtain a concentration of 30 mg/I (dry weight) in 250 ml flask, 2.27 ml of sludge is needed (inoculum)

- Nominal concentrations:
test substance: 100 mg/L
test substance: 100 mg/L

- Test temperatures: 22 °C

- Test duration: 38 days

- inital pH: 7.55

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

48

Sampling time:

28 d

Details on results:

GR-85-2517 undergoes 48% biodegradation after 28 days (56% after 34 days) in the test conditions. Biodegradation exceeds 10% on day 19 after a long lag phase and reaches only 50% at the end of the 10-day windiw (Days 1 to 29).

The curves obtained with the reference substance alone and with GR-85-2517 + reference substance show no toxic effect of GR-85-2517 to the micro- organisms at the test concentration (100 mg /l).

Results with reference substance:

Degradation of Sodium benzoate exceed 40% after 7 days and 65% after 14 days: the activity of the inoculum is thus verified (validity criterion).

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

GR-85-2517 should be regarded as not readily biodegradable according to this test

Executive summary:

The ready biodegradability of GR-85-2517 was determined by Manometric Respirometry Test according to the OECD Guidelines for Testing of Chemicals, Method No 301 F.

GR-85 -2517 undergoes 48% biodegradation after 28 days (56% after 34 days) in the test conditions. Biodegradation exceeds 10% on day 19 after long lag phase and reaches only 50% at the end of the 10 -day window (days 19 to 29).

The curves obtained with the reference susbtance alone and with GR-85-2517 + reference substance show no toxic effect of GR-85 -2517 to the micro-organisms at the test concentration (100 mg/l).

Thus, GR-85 -2517 should be regarded as not readily biodegradable according to this test.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

21 March 2013 - 4 July 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Aspect: Yellow liquid
Purity: 91.0%
Expiration date: January 10, 2014

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

Fresh activated sludge from a biological waste water treatment plant treating predominantly domestic sewage (Bois de Bay, Satigny, Switzerland) was used.

The sludge is collected in the morning, washed three times in the mineral medium (by centrifuging at 1000g for 10 minutes, discarding the supernatant and resuspending in mineral medium) and kept aerobic until being used on the same day.

Duration of test (contact time):

38 d

Initial conc.:

30 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Test conditions:

- Activated sludge
Dry weight of suspended solids: 4.74 g/L, diluted to 2,62 g/L
To obtain a concentration of 30 mg/I (dry weight) in 437 ml total volume, 5.00 ml of sludge (inoculum) was added to 432 ml of mineral medium.

- Nominal concentrations:
test substance: 30 mg/L
test substance: 100 mg/L

- Test temperatures: 21.9 - 22.2 °C

- Test duration: 38 days

- inital pH: 7.5

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

79

Sampling time:

28 d

Details on results:

The 10-day window criterion is fulfilled (16% biodegradation on day 5 and 71% on day 15)

Results with reference substance:

Degradation of sodium benzoate exceeded 40% after 7 days and 65% after 14 days: the activity of the inoculum was thus verified (validity criterion).

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Pomarose did not inhibit the intrinsic respiration of the inoculum at the test concentration and was therefore considered to be non toxic to the inoculum at the test concentration.

Pomarose should be regarded as readily biodegradable according to this test.

Executive summary:

The Ready biodegradability of Pomarose was determined by the manometric respirometry test.

Pomarose undergoes 79% biodegradation after 28 days in the test conditions. The 10 - day window criterion is also fulfilled (16% biodegradation on day 5 and 71% on day 15).

Pomarose did not inhibit the intrinsic respiration of the inoculum at the test concentration and was therefore considered to be non toxic to the inoculum at the test concentration.

Pomarose should be regarded as readily biodegradable according to this test.

Description of key information

Studies available:

Two biodegradation studies following the OECD guideline 301F procedure was performed on Pomarose in 2004 and 2013. The test item concentration used in these studies are respectivelly 100 mg/l and 30 mg/l.

The two studies are approximatelly of the same quality, however the concentration that could be found in the environment would be well below 100 mg/l. Therefore the test item concentration used in the 2013 study is more environmentally relevant. That is why this study was chosen as the key study for this endpoint.

Key results:

Pomarose undergoes 79% biodegradation after 28 days in the test conditions. The 10 - day window criterion is also fulfilled (16% biodegradation on day 5 and 71% on day 15).

Pomarose did not inhibit the intrinsic respiration of the inoculum at the test concentration and was therefore considered to be non toxic to the inoculum at the test concentration.

Pomarose should be therefore regarded as readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater