Enoxolone

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:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Enoxolone

EC Number:

207-444-6

EC Name:

Enoxolone

Cas Number:

471-53-4

Molecular formula:

C30H46O4

IUPAC Name:

3-hydroxy-11-oxoolean-12-en-30-oic acid

Test material form:

solid: particulate/powder

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, adapted

Details on inoculum:

Activated sludge from a biologic sewage treatment plant was used as inoculum. The cho-sen plant is treating mostly domestic sewage.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

20 mg/L

Based on:

ThCO2

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Results and discussion

% Degradation

% Degradation 1

Key result

Parameter:

% degradation (CO2 evolution)

Value:

73

Sampling time:

10 d

% Degradation 2

Key result

Parameter:

% degradation (CO2 evolution)

Value:

84

Sampling time:

28 d

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

All validity criteria were met.
Degradation behaviour of positive control and toxicity control was normal. Abiotic degradation was not observed. Both replicates of the test item showed very good correspondence.
If degradation in the toxicity flask is below 25 % after 14 days, the test item can be consid-ered as toxic towards the inoculum. As degradation in the toxicity flask was 79.3 % after 14 days, the test item can be stated as “not toxic towards the inoculum in a concentration of 26.3 mg/L”.
Ready biodegradability is defined in the guidelines as degradation surpassing 60% within 10 days after reaching a level of 10 %. Therefore, the test item Enoxolone can be considered as “readily biodegradable”.
No observations were made which might cause doubts concerning the validity of the study outcome.
The result of the test can be considered valid.