4,4-dimethyl-3,5,8-trioxabicyclo[5.1.0]octane

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

May - Jun 1995

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)

Version / remarks:

1993

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: activated sludge collected from a municipal sewage treatment plant (predominantly domestic sewage)
- Storage length: 24 hours
- Preparation of inoculum for exposure: nutrient solution containing phosphates, ammonium chloride, vitamins and trace elements were added to the test solution.
- Pretreatment: sludge samples were taken one day before start of the test. The sewage sludge was kept under aerobic conditions until test initiation. Approximately 1 hour before start of the test, aeration was discontinued. The inoculum was obtained from the supernant.

Duration of test (contact time):

28 d

Initial conc.:

20 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium: 57.6 mL of the test solution, 15 mL nutrient solution, 926.9 mL demineralized water
- Test temperature: 21 +/- 1°C
- pH: 7.6
- pH adjusted: no
- Aeration of dilution water: yes
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 2 L glass beakers incubated on a magnetic stirrer
- Number of culture flasks/concentration: 3 replicates
- Method used to create aerobic conditions: aeriation by constant stirring
- Measuring equipment: DOC-analyses by carbon anylser

SAMPLING
- Sampling frequency: sampling at day 1, 2, 5, 8, 15, 21, 28, 29

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 3 replicate
- Toxicity control: yes, 1 replicate
- Reference substance (sodium acetate): yes, 1 replicate:

Reference substance:

acetic acid, sodium salt

Key result

Parameter:

% degradation (DOC removal)

Value:

15

Sampling time:

28 d

Details on results:

The toxicity control (sodium acetate + test substance at equal DOC concentrations) was degraded to 58% at day 28. The used concentration of the test substance did not show toxic effects to bacteria.

Results with reference substance:

The reference substance (sodium acetate) was degraded to 97% on day 5.

Validity criteria for the measurement of the biodegradation according to OECD 301:

Target condition according to guideline:	Actual condition according to the study:	Validity criteria met:
In order to check the procedure, reference compounds which meet the criteria for ready biodegradability are tested by setting up an appropriate vessel in parallel as part of normal test runs. Suitable compounds are aniline (freshly distilled), sodium acetate and sodium benzoate.	Acetic acid, sodium salt was used as a reference compound.	Yes
A test is considered valid if the difference of extremes of replicate values of the removal of the test chemical at the plateau, at the end of the test or at the end of the 10-d window, as appropriate, is less than 20% and if the percentage degradation of the reference compound has reached the pass levels by day 14.	At the end of the test, at the plateau, or the end of the 10-d window, biodegradation in parallels with test item did not differ by more than 20 percentage points.	Yes
If in a toxicity test, containing both the test substance and a reference compound, less than 35% degradation (based on total DOC) or less than 25% (based on total ThOD or ThCO2) occurred within 14 days, the test substance can be assumed to be inhibitory. The test series should be repeated, using a lower concentration of test substance (if this can be done without seriously impairing the accuracy of the DOC determination) and/or a higher concentration of inoculum, but not greater than 30 mg solids/L.	The reference compound reached the level of ≥ 60 percent for ready biodegradability within 14 days.	Yes

 

Validity criteria fulfilled:

yes

Remarks:

See 'Any other information on results incl. tables'.

Interpretation of results:

not readily biodegradable

Conclusions:

The test substance showed 15% degradation within 28 days. Therefore, the test substance is considered to be ''Not Readily Biodegradable'.

Executive summary:

The study was performed to determine the ready biodegradability of the test substance. The study was conducted in accordance with the OECD Guideline 301 E 'Modified OECD Screening test'. The test substance was incubated in aqueous solutions including nutrients with microorganimsm from a municipal sewage treatment plant for 28 days under aerobic conditions. The test concentration was 20 mg/L as dissolved organic carbon (DOC) for the test substance. The biological degradation of the test substance was evaluated by the decrease of DOC in the solutions. DOC was anylzed on day 1, 2, 5, 8, 15, 21, 28 and 29. The test substance showed 15% degradation within 28 days. Therefore, the test substance is considered to be 'Not Readily Biodegradable'. The used concentration of the test substance did not show toxic effects to bacteria.

Description of key information

A study was performed to determine the ready biodegradability of the test substance. The study was conducted in accordance with the OECD Guideline 301 E 'Modified OECD Screening test'. The test substance was incubated in aqueous solutions including nutrients with microorganimsm from a municipal sewage treatment plant for 28 days under aerobic conditions. The test concentration was 20 mg/L as dissolved organic carbon (DOC) for the test substance. The biological degradation of the test substance was evaluated by the decrease of DOC in the solutions. DOC was anylzed on day 1, 2, 5, 8, 15, 21, 28 and 29. The test substance showed 15% degradation within 28 days. Therefore, the test substance is considered to be 'Not Readily Biodegradable'. The used concentration of the test substance did not show toxic effects to bacteria.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater