2-Oxazolidinone, 3-ethenyl-5-methyl-

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16-09-2019 - 08-01-2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Source and Collection:
A fresh sample of activated sludge was collected on 15th Oct. 2019 from the aeration tank of the Zhu Yuan Domestic Wastewater Treatment Plant in Shanghai which treats predominantly domestic sewage. Use the sludge within day of sampling and the activated sludge was kept aerobic until use.

Treatment of inoculum:
Coarse particles were removed by filtration through a fine sieve (1 mm) and the sludge was kept aerobic thereafter. After removal of any coarse particles, the sludge was separated by centrifuging for 20 minutes at 4000 rpm, 4°C. The supernatant was discarded. The sludge was then washed in the mineral medium. The re-suspended sludge was then centrifuged after thorough mixing, supernatant discarded and the washed sludge was re-suspended in a further volume of mineral medium. This procedure was repeated 3 times. A small amount of the washed sludge (0.4g) was weighed and dried by moisture meter at 10500 for 1 h to calculate the dry weight which was 5.50%.

Sludge suspension:
127.27g wet sludge(dry matter weight was about 7g) was suspended in 7L mineral medium to obtain the concentration of 1 g dry matter/L. The sludge suspension was used as the inoculum. The final concentration of sludge in test solution was 0.25 g dry matter/L (0.25g SS/L).

Pretreatment: none

Duration of test (contact time):

28 d

Initial conc.:

70 mg/L

Based on:

other: Total Organic Carbon (TOC) nominal

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium: according to guideline
- Solubilising agent (type and concentration if used): no
- Test temperature: 20.0 – 20.7°C
- pH: 7.0 – 7.6
- pH adjusted: yes
- Suspended solids concentration: 0.25 g/L dry weight
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 5L incubation vessels
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: aeration with cleaned air
- Measuring equipment: The determination of dissolved organic carbon (DOC) was performed by Carbon analyser (Jena Multi N/C 3100, software: Multiwin v4.09)
- Test performed in open system: yes

SAMPLING
- Sampling frequency: 3h after test start and Day 3, 6, 10, 14, 17, 22, 27 and 28.
- Sampling method: The samples of the sludge suspensions (inoculum blank, test substance, toxicity and procedure control) were filtered by a 0.22 pm membrane as soon as they are taken, discarding the first 5 mL of filtrate and then analyzed directly by carbon analyzer. The quantity of sample added was about 25 mL
- Sample storage before analysis: No storage before analysis

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Procedure control: yes (Positive control)
- Toxicity control: yes

Reference substance:

diethylene glycol

Remarks:

200 mg/L in test

Test performance:

Test substance preparation
The water solubility of test substance is 90.9 g/L , therefore, the test substance was added by preparing stock solution. To prepare the stock solution of test substance, 1500.4mg of test substance was dissolved in 3L mineral medium and the concentration of stock solution was 500mg/L.
Reference substance preparation
To prepare the stock solution of reference substance, 2000.1mg of diethylene glycol was dissolved in 1 L mineral medium and the concentration of stock solution was 2g/L. The final concentration of reference substance in the test system was 200mg/L.
Sampling
The losses due to evaporation were immediately replaced prior to each sampling. Analysis of DOC was carried out by the DOC analysis on 3h and Days 3, 6, 10, 14, 17, 22, 27 and 28.

Determination of temperature, pH and dissolved oxygen (DO)
The temperature, pH and dissolved oxygen of each flask was determined on each day of sampling. Keep the temperature in the range of 20-24 0C and the dissolved oxygen higher than 1 mg/L, adjust to pH 6.5-8.0 with NaOH (40 g/L) or H2S04 (50 g/L) if necessary.

Parameter:

% degradation (DOC removal)

Value:

7

Sampling time:

28 d

Details on results:

During the 28-d test, the temperature was in the range of 20.0-20.7°C (in the range of 20-25 °C), the pH of test vessels was between 6.594-7.946, and the dissolved oxygen (DO) of each test vessels was from 6.57 mg/L to 8.70 mg/L (higher than 1 mg/L).
The relative degradation values calculated from the DOC analysis performed during the test period indicated that the average percentage biodegradation on the 28th day was 7%.

Results with reference substance:

The average percentage degradation of procedure control was 100% after 14 days. It is concluded that the inoculum degradation activity meets the requirements of this test.
The degradation percentage of toxicity control on day 14 was 56%, which was higher than the toxicity inhibition level (>25%). It is concluded that the test substance has no inhibitory effects on inoculumn at the test concentration.

Validity criteria fulfilled:

yes

Interpretation of results:

not inherently biodegradable

Conclusions:

The test substance was found to be not inherently biodegradable under the present test conditions.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

03-03-2015 - 01-04-2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study without restrictions

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

prolonged test duration of 60 days

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Municipal activated sludge from the wastewater treatment plant of Mannheim, Germany
- Storage conditions: The inoculum was collected from the aeration tank of the plant and aerated in the laboratory until use. 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 72 hours at 22 ± 2° C,
- Preparation of inoculum for exposure: At the day of exposure the suspension was washed one time with tap 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 tap water and the concentration of the sludge was adjusted to 6.0 g/L dry weight.
- Pretreatment: none
- Concentration of sludge: 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 conc.:

20 mg/L

Based on:

other: Total Organic Carbon (TOC) nominal

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: according to guideline
- Solubilising agent (type and concentration if used): no
- Test temperature: 22+/- 2°C
- pH adjusted: 7.4 +/- 0.2
- Suspended solids concentration: 30 mg/L dry weight

TEST SYSTEM
- Culturing apparatus: 2L incubation vessels
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: aeration with carbon dioxide free air
- Measuring equipment: The determination of total carbon in solids is performed using a solid sample module SSM-5000A connected with a TOC-analyzer (Shimadzu TOC-5000A).
- Test performed in closed vessels: yes
- Test performed in open system: no
- 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.
The TIC-value of the freshly prepared sodium hydroxide solution was determined and considered by the calculation of biogenic produced carbon dioxide amount. The incubation bottles were stirred on magnetic stirrers; the aeration was performed with carbon dioxide free air at a flow of approximately 800 mL per hour.

SAMPLING
- Sampling frequency: every 2-5 days

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Inhibition control: yes
- Toxicity control: yes

Reference substance:

aniline

Parameter:

% degradation (CO2 evolution)

Value:

< 10

Sampling time:

28 d

Validity criteria fulfilled:

yes

Description of key information

The substance is not readily biodegradable and no inherently biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

other: OECD 302B mineral medium

Additional information

The conclusion that 5-Methyl-3-vinyloxazolidin-2-on was not 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 not reached. The degree of biodegradation after an exposure period of 28 days was < 10% CO2/ThCO2 in this test.

The conclusion that 5-Methyl-3-vinyloxazolidin-2-on was not inherent biodegradable is based on the results of a study according to OECD, in which the reduction of dissolved organic carbon was determined. The degree of biodegradation after an exposure period of 28 days was 7% DOC in this test.