5-methyl-1,3-oxazolidin-2-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:

2015-04-21 - 2015-05-19

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study according to OECD guideline

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

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:

5-methyl-1,3-oxazolidin-2-one

EC Number:

810-292-9

Cas Number:

1072-70-4

Molecular formula:

C4H7NO2

IUPAC Name:

5-methyl-1,3-oxazolidin-2-one

Details on test material:

- Name of test material (as cited in study report): 5-methyl oxazolidin-2-one
- Physical state: Liquid/colorless, clear
- Analytical purity: 98.0 area-% (GC)
- Lot/batch No.: EWALD-00441
- Expiration date of the lot/batch: 19 Jan 2017
- Stability under test conditions: stable
- Storage condition of test material: at room temperature
- Water solubility: Miscible in any ratio

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum (location, sampling depth, contamination history, procedure): Municipal activated sludge from the wastewater treatment plant of Mannheim, Germany. The inoculum was collected on 20 April 2015 from the aeration tank of the plant. A suitable aliquot of the activated sludge suspension was sieved by a finely woven mesh with a mesh size about 1 mm. To reduce the content of inorganic carbon in the blank controls the activated sludge was aerated with carbon dioxide free air for about 24 hours at 22 ± 2° C.

- Preparation of inoculum for exposure: At the day of exposure the suspension was washed one time with drinking water. Therefore the aeration was stopped and the sludge was allowed to settle. After settling the supernatant was discarded and the remaining sludge suspension was filled up with drinking water and the concentration oft the sludge was adjusted to 6.0 g/L dry weight. Aliquots of 7.5 mL were added to the test vessels to obtain an activated sludge concentration of 30 mg/L dry weight.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

20 mg/L

Based on:

other: TOC

Initial test substance concentration 2

Initial conc.:

42 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: acccording to the guideline
- Test temperature: 22 ± 2° C.
Due to technical malfunction of the electricity supply the test temperature was
marginally above 24 °C for a short time. An impact to the test result can be excluded
- pH: 7.1 - 7.7
- pH adjusted: The pH-values in the test vessels were measured and adjusted to 7.4 ± 0.2, if
necessary
- Aeration of dilution water: the aeration was performed with carbon dioxide free air at a flow of approximately 800 mL per hour


TEST SYSTEM
- Culturing apparatus: 2 L incubation bottles
- Number of culture flasks/concentration: 2
- Measuring equipment: carbon dioxid trap
- Details of trap for CO2 and volatile organics if used: The bottles were connected to two serial scrubbing bottles (total
volume 250 mL) filled with 100 mL 0.05 mol sodium hydroxide solution for the
adsorption of carbon dioxide from biodegradation processes. Usually twice a week the
Total Inorganic Carbon (TIC) values of the adsorption solutions of the first trap were
determined and used for the calculation of the produced carbon dioxide. After each
sampling the second trap was moved forward and the new trap with fresh sodium
hydroxide solution was placed into the second position. Each trap was analyzed
separately.

SAMPLING
- Sampling frequency: Usually twice a week

CONTROL AND BLANK SYSTEM
-2 blank control assays (BC)
2 test substance assays (TS)
1 inhibition control test assay (IH)
1 reference substance assay (RS)

Reference substance

Reference substance:

aniline

Results and discussion

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

60 - 70

Sampling time:

28 d

BOD5 / COD results

Results with reference substance:

Degree of biodegradation of the reference substance after 14 days: 71 % CO2/ThCO2

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The conclusion that 5-methyl oxazolidin-2-one was readily biodegradable in this
carbon dioxide evolution test based on the quantitative determination of the formed
carbon dioxide in the test substance assays by comparison with the calculated maximal
theoretical carbon dioxide production.
The required pass level for ready biodegradability within a ten days window was
reached.
The degree of biodegradation after an exposure period of 28 days was 60-70 %
CO2/ThCO2 in this test.
The degree of biodegradation was calculated as mean of the values from two test
assays at the end of exposure.
The results in this study are consistent with all validity criteria and the test is valid
according to the test guideline of this study. No deviations from the test guidelines or
other incidents occurred during the course of the reported test, which may have
influenced the results.