Oligomerisation products of plasma treated triglycerides, C16-18 (even numbered) and C18 (unsaturated)

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:

2019

Report date:

2019

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

July 1992

Deviations:

yes

Remarks:

- Temperature range 19.1 – 22.2 °C instead of 20.0 – 24.0 °C. Uncritical deviation. - The flasks for IC measurement were stored at 3.7 – 7.9 °C instead of 4 °C. Uncritical deviation.

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Version / remarks:

May 2008

Deviations:

yes

Remarks:

idem

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

vegetable oil mono- and polyunsaturated C16-C22 triglycerides

Molecular formula:

C51H92O6 to C69H128O6

IUPAC Name:

vegetable oil mono- and polyunsaturated C16-C22 triglycerides

Constituent 2

Reference substance name:

dimers of vegetable oil mono- and polyunsaturated C16-C22 triglycerides

Molecular formula:

C102H186O12 to C138H256O12

IUPAC Name:

dimers of vegetable oil mono- and polyunsaturated C16-C22 triglycerides

Constituent 3

Reference substance name:

trimers of vegetable oil mono- and polyunsaturated C16-C22 triglycerides

Molecular formula:

C153H280O18 to C207H388O18

IUPAC Name:

trimers of vegetable oil mono- and polyunsaturated C16-C22 triglycerides

Constituent 4

Reference substance name:

tetramers and higher oligomers of vegetable oil mono- and polyunsaturated C16-C22

Molecular formula:

C204H374O24 and higher oligomers

IUPAC Name:

tetramers and higher oligomers of vegetable oil mono- and polyunsaturated C16-C22

Test material form:

liquid: viscous

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: ESN Stadtentsorgung Neustadt sewage treatment plant, Im Altenschemel, 67435 NW-Lachen-Speyerdorf.
- Storage conditions:
- Storage length: 3 days (May 17th to May 20th)
- Pre-treatment of the sludge: the sludge was filtrated, washed with test medium (2x) and re-suspended in test medium. It was then aerated until use.
- Concentration of sludge: The dry matter was determined to contain 4.98 g of suspended solids/L.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

20 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

PRE-TEST
The carbon content of 76.70 % (mean of 76.80 % and 76.60 %) was determined by ele-mental analysis under non-GLP conditions, performed at laboratory Mikroanalytisches Labor Pascher, An der Pulvermühle 1, 53424 Remagen, Germany. Before using, the test item was shaken. Then, the test item was pipetted into the flasks directly, using the densi-ty 0.92 g/cm3 given by the sponsor. The amounts were calculated from the carbon con-tent, determined by elemental analysis.

TEST CONDITIONS
- Composition of medium: see below.
- Test temperature: 19.1-22.2°C
- pH: 7.5
- pH adjusted: no
- Aeration of dilution water: Flasks filled with medium and inoculum were aerated for 72 hours with purified CO2-free, moistened air to purge the system of CO2.
- Suspended solids concentration: 4.98 g suspended solids/L; inoculum concentration: 25.0 mg/L.
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 1500 mL flasks
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: The test vessels were aerated with purified (by activated charcoal), CO2-scrubbed, moistened air.
- Details of trap for CO2 and volatile organics if used: The emitted CO2 was trapped in 0.25 M NaOH. Two scrubbers containing 100 mL each were connected in series to the test vessels. The initial IC value of the 0.25 M NaOH was separately determined in each flask.

SAMPLING
- Sampling frequency: on day 0, 2, 4, 7, 9, 11, 14, 18, 23 and 29
- Sampling volume: 1 mL. The resulting change in the volume of the front flask was considered in the calculation of emitted CO2.

CONTROL AND BLANK SYSTEM
- Apparatus blank: yes, 2 flasks containing mineral medium only
- Inoculum blank: yes, 2 flasks containing mineral medium and inoculum
- Positive control: yes: 2 flasks containing positive control, mineral medium and inoculum
- Abiotic sterile control: yes: 1 flask containing test item, mineral medium and HgCl2
- Toxicity control: yes: 1 flask containing test item, positive control, mineral medium and inoculum

Reference substance

Reference substance:

aniline

Results and discussion

Preliminary study:

The carbon content of the test item was determined to be 76.70%.

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

67.3

Sampling time:

29 d

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Executive summary:

The test item Oligomerisation product obtained by plasma treatment of vegetable oil mono- and polyunsaturated C16-C22 triglycerides was tested using a concentration of nominally 20 mg organic carbon/L of test item in test medium following OECD 301B and EU-Method C.4-C. Activated sludge was used as inoculum (concentration in the test 25.0 mg dry matter/L). The test was left running for 28 days.

The following data were determined for the test item Oligomerisation product obtained by plasma treatment of vegetable oil mono- and polyunsaturated C16-C22 triglycerides.:

- 10-day-window: day 4 to 14
- degradation at the end of 10-day-window: 51%
- degradation at the end of the test: 67%
According to the guideline, the pass level is 60 % of degradation at the end of 10-day-window for pure substances and 60 % of degradation at the end of the test for mixtures. Because the test item is a mixture, the 10-day-window does not have to be taken into account. As degradation reached the pass level of 60% in the course of the test, the test item is considered readily biodegradable within 28 days.