4-(2,6,6-trimethyl-2-cyclohexen-1-yl)butan-2-one

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:

From Nov 23,2017 to January 18,2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

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)

Test material

Test material information

Constituent 1

Reference substance name:

4-(2,6,6-trimethyl-2-cyclohexen-1-yl)butan-2-one

EC Number:

250-657-4

EC Name:

4-(2,6,6-trimethyl-2-cyclohexen-1-yl)butan-2-one

Cas Number:

31499-72-6

Molecular formula:

C13H22O

IUPAC Name:

4-(2,6,6-trimethylcyclohex-2-en-1-yl)butan-2-one

impurity 1

Reference substance name:

4-(2,2-dimethyl-6-methylenecyclohexyl)butan-2-one

EC Number:

237-283-7

EC Name:

4-(2,2-dimethyl-6-methylenecyclohexyl)butan-2-one

Cas Number:

13720-12-2

Molecular formula:

C13H22O

IUPAC Name:

4-(2,2-dimethyl-6-methylenecyclohexyl)butan-2-one

Test material form:

liquid

Specific details on test material used for the study:

Lot No: SC00021444
Purity: 91.0% (Major Peak)
Expiration Date: October 06,2019

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, 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 1000 g 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):

49 d

Initial test substance concentration

Initial conc.:

30 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

A measured volume of inoculated mineral medium, containing a known concentration of test substance as the nominal sole source of organic carbon, is stirred in a closed flask at a constant temperature (± 1°C) for up to 28 days. Evolved carbon dioxide is absorbed in sodium hydroxide pellets. The consumption of oxygen is determined by measuring the pressure drop in the respirometer flask. The Biological Oxygen Demand (BOD), amount of oxygen taken up by the microbial population during biodegradation of the test chemical (corrected for uptake by blank inoculum, run in parallel) is expressed as a percentage of ThOD (Theoretical Oxygen Demand, calculated from the elemental composition, assuming that carbon is oxidized to carbon dioxide, hydrogen to water and nitrogen to ammonium, nitrite or nitrate).

Reference substance

Reference substance:

benzoic acid, sodium salt

Remarks:

Sodium Benzoate (purity 99%)

Results and discussion

% Degradation

Key result

Parameter:

% degradation (O2 consumption)

Value:

70

Sampling time:

28 d

Details on results:

Dihydro Ionone Alpha undergoes 70% biodegradation after 28 days in the test conditions.
The 10-day window criterion is not fulfilled (10% biodegradation on day 4 and 46% on day 14).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable, but failing 10-day window

Conclusions:

Dihydro Ionone Alpha should be regarded as readily biodegradable, but failing the 10-day window.