2-(3,7-dimethylocta-2,6-dienyl)cyclopentan-1-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:

October 29, 2015 - January 5, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The analog substance has a very similar chemical structure to the substance being registered. The reported substance has a C8 carbon chain with two methyl groups and two double bonds, and the analog substance has a C9 carbon chain with two methyl groups and two double bonds in the same positions.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Both the source and target substances were tested in very pure forms. The target substance was tested at 100% purity, and the source substance was tested at 99% purity with 1% tocopherol added as a preservative.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

Test results from one test substance flask were improperly recorded. The results reported are based on the results for the other two flasks.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-(3,7-dimethyl-2,6-nonadien-1-yl)-cyclopentane

Cas Number:

1206769-45-0

Molecular formula:

C16H26O

IUPAC Name:

2-(3,7-dimethyl-2,6-nonadien-1-yl)-cyclopentane

additive 1

Reference substance name:

3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-benzopyran-6-ol

EC Number:

233-466-0

EC Name:

3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-benzopyran-6-ol

Cas Number:

10191-41-0

Molecular formula:

C29H50O2

IUPAC Name:

2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)chroman-6-ol

Test material form:

liquid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Easton Wastewater Treatment Facility
- Storage conditions: aerated at test temperature until use
- Storage length: plates incubated for 48 hrs
- Initial cell/biomass concentration: 1,000 mg total suspended solids/L
- Water filtered: yes
- Type and size of filter used, if any: 2 mm

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

10 other: mg C/L

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: modified biochemical oxygen demand test dilution water prepared with high quality water
- Test temperature: 20 +/- 3 degrees C
- pH: 7.6
- pH adjusted: yes
- Aeration of dilution water: yes
- Suspended solids concentration: =< 30 mg/L

TEST SYSTEM
- Culturing apparatus: 4 L amber bottles
- Number of culture flasks/concentration: 3
- Method used to create aerobic conditions: Air entering chambers was passed over Drierite and then Ascariate. Aeration was done for a 24-hr period , and then the flow of air was stopped.
- Details of trap for CO2 and volatile organics if used: Air exiting the test bottles was passed through three gas washing bottles. Each of the gas washing bottles contained 100 mL of 0.5 M KOH.

SAMPLING
- Sampling frequency: days 3, 6, 8, 13, 17, 20, 23, and 27
- Sampling method: The CO2 trap nearest the test chamber was removed. The two other traps were moved down one position, and then a new trap added.
- Sample storage before analysis: Samples from the end of the study were aerated overnight, and then a sample removed for dissolved organic carbon analysis.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: yes
- Toxicity control: yes

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

Test performance:

The value of CO2 evolved in the blank control chambers did not exceed 40 mg/L. The reference substance produced an average of 90.9% of theoretical CO2 evolved. Thus, the study is valid. The toxicity control degraded > 25% by day 14, and thus the substance is non-inhibitory at the test concentration.

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

73

Sampling time:

27 d

Details on results:

The average percent biodegradation was greater than 60% by day 6. Thus fulfilling the 10 day window requiremetn.

BOD5 / COD results

Results with reference substance:

The reference substance produced an average of 90.9% of theoretical CO2 evolved.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The substance methyl apritone is readily biodegradable.

Executive summary:

The ready biodegradability of the test substance methyl apritone was determined in an OECD 301B test. Inoculum was exposed to the test substance for 29 days, during which the amount of carbon dioxide evolved was measured. Sodium benzoate was used as a reference substance with toxicity controls, and inoculum blanks tested as well. Results of the controls and blanks were valid. The substance was degraded an average of 73%, and met the 10 -day window requirement. The substance is therefore readily biodegradable.