Registration Dossier

Environmental fate & pathways

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 guidelineopen allclose all
Qualifier:
according to
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.
Qualifier:
according to
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. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Type:
Constituent
Type:
Constituent
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.