4-tert-butylcyclohexanone

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

4-tert-butylcyclohexanone

EC Number:

202-678-5

EC Name:

4-tert-butylcyclohexanone

Cas Number:

98-53-3

Molecular formula:

C10H18O

IUPAC Name:

4-tert-butylcyclohexan-1-one

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic (adaptation not specified)

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

2.4 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Incubation temperature: 20 +/- 1°C

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

Test performance:

All validity criteria of the test method were met:
- The reference substance has reached the level for ready biodegradability by 14 days.
- No toxicity of the test substance was observed in the toxicity control.
- The difference of extremes of replicate values of the removal of test chemical at the end of the test is less than 20 %.
- Oxygen depletion in the inoculum blank did not exceed 1.5 mg/l dissolved oxygen after 28 days.

% Degradation

% Degradation 1

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

7 d

% Degradation 2

Parameter:

% degradation (O2 consumption)

Value:

14

Sampling time:

14 d

% Degradation 3

Parameter:

% degradation (O2 consumption)

Value:

23

Sampling time:

21 d

% Degradation 4

Parameter:

% degradation (O2 consumption)

Value:

32

Sampling time:

28 d

Details on results:

Within 28 days, a degradation of 32% was determined for p-tert.-Butylcyclohexanon rein.
p-tert.-Butylcyclohexanon rein has to be classified as ¿Not Readily Biodegradable¿

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Conclusions:

Within 28 days, a degradation of 32% was determined for p-tert.-Butylcyclohexanon rein.
p-tert.-Butylcyclohexanon rein has to be classified as ¿Not Readily Biodegradable¿

Executive summary:

A study was performed to assess the ready biodegradability of p-tert-Butylcyclohexanon rein. The principles of Good Laboratory Practice (GLP) were applied.

The study was conducted in accordance with the Council Directive 92/69/EEC Method C.4-E: Closed Bottle Test. This test method is in all essential parts identical with OECD Guideline 301 D.

The method assesses the ready biodegradability of a test substance under aerobic conditions at 20 ± 1°C in the dark. The test substance p-tert.-Butylcyclohexanon rein in a mineral medium was inoculated with secondary effluent and incubated for 28 d under aerobic conditions in completely full, closed bottles. During this period the biodegradation is followed by analysis of dissolved oxygen. The amount of oxygen taken up by the test chemical, corrected for uptake by the blank inoculum run in parallel, is expressed as a percentage of theoretical oxygen demand (ThOD) or chemical oxygen demand (COD).

p-tert.-Butylcyclohexanon rein showed:

0 % degradation after 7 days.

14 % degradation after 14 days.

23 % degradation after 21 days.

32 % degradation after 28 days.

Therefore p-tert.-B utylcyclohexanon rein has to be classified as ¿Not Readily Biodegradable¿.

No toxicity of the test substance was observed in the toxicity control.

The reference compound showed 75 % degradation after 14 days.