Reaction mass of stigmast-5-en-3-β-ol and stigmasta-5,22-dien-3-β-ol and (24R)-ergost-5-en-3β-ol

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

Report date:

2020

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of (24R)-ergost-5-en-3β-ol and stigmast-5-en-3-β-ol and stigmasta-5,22-dien-3-β-ol

EC Number:

904-790-6

Molecular formula:

C28H48O; C29H50O; C29H48O

IUPAC Name:

Reaction mass of (24R)-ergost-5-en-3β-ol and stigmast-5-en-3-β-ol and stigmasta-5,22-dien-3-β-ol

Study design

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

76.5 mg/L

Based on:

COD

Initial test substance concentration 2

Initial conc.:

150 mg/L

Based on:

test mat.

Details on study design:

For the test concentration and for the negative control, 100 mL capacity conical glass flasks
capped with air permeable stoppers were used.
Six replicates for test concentration and six for negative control were prepared. At test start,
50 mL of test solutions were poured into the test flasks and inoculated with algae to obtain a
starting cell density of about 104 cells/mL.
For the test concentration and for the negative control, 100 mL capacity conical glass flasks
capped with air permeable stoppers were used.
Six replicates for test concentration and six for negative control were prepared. At test start,
50 mL of test solutions were poured into the test flasks and inoculated with algae to obtain a
starting cell density of about 104 cells/mL.

Temperature: 21.6-23.1 °C
Light conditions: darkness
Stirring: continuous

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (O2 consumption)

Value:

126.1

Sampling time:

28 d

% Degradation 2

Parameter:

% degradation (O2 consumption)

Value:

61.4

Sampling time:

10 d

Details on results:

The ThOD NH3 value was calculated to be equal to 1.67 mg O2/mg for reference item, Sodium benzoate, while COD value was assessed to be 0.51 mg O2/mg for the test item.
These values were used to calculate % biodegradation.
At the start and test end no nitrite and nitrate were present.
No significacnt degradation was observed in the abiotic control (equal to 5.2% at the test end).
The test item does not cause inhibitory effect on the microorganisms activity at the tested concentration. Actually, the toxicity control exceed the 25% pass level within the 14 days of exposure (81,3%).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

At the end of the test the biodegradation was 126.1% (mean % values between two replicates).
Therefore, the test item was found to be ready and completely biodegradable under the conditions applied in a manometric respirometry test, since at the end of the 10-day window the biodegradation was 61.4% and a maximum biodegradation of 126.1% was found at the end of the test (mean % values between two replicates).

The test item showed no inhibitory effects on the microorganism activity at the tested concentration, as demonstrated by the biodegradation percentage in the toxicity cotrol exceeding the 25% pass level within 14 days of exposure (81.3%).