Esterification products of glycerol with docosanoic acid, icosanedioic acid and 16-methylheptadecanoic acid

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:

17.Aug. 2016 - 21. Apr. 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 5-10-A
- Expiration date of the lot/batch: 19.Oct. 2018
- Purity test date: a9. Oct. 2015

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: stored in a tightly closed vessel at 18.3 - 20.5 °C under dry conditions in the dark
- Stability under test conditions: assumed stable
- Solubility and stability of the test substance in the solvent/vehicle: assumed stable
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: assumed none

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
none

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): activated sludge from biologic sewage treatment plant (NW-Lachen-Speyerdorf)

- Pretreatment: The sludge was filtrated, washed with tap water (2x), then washed with and re-suspended in the test medium. it was then aerated until use.
- Dry matter: 4600 mg suspended solids/L
- Concentration of sludge: 25.0 mg/L
- Water filtered: no

Duration of test (contact time):

ca. 28 d

Initial conc.:

ca. 26 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium:
Stock solution a: Potassium dihydrogen phosphate 8.5 g, Dipotassium hydrogen phosphate 21.75 g, Disodiumhydrogen phosphate dihydrate 33.4 g, Ammonium chloride 0.5 g, H2O demin. ad 1000 mL
Stock solution b: Calcium chloride 27.5 g, H2O demin. ad 1000 mL
Stock solution c: magnesium sulphate heptahydrate 22.5 g, H2O demin. ad 1000 mL
Stock solution d: Iron(III) chloride hexahydrate 0.25 g, Di-sodium-ethylene diaminetetraacetate dihydrate 0.4 g, H2O demin. ad 1000 mL
Test medium: Solution a 10 mL, Solution b 1 mL, Solution c 1 mL, Solution d 1 mL, H2O demin. ad 1000 mL

- Test temperature: 19.8 - 32.5 °C
- pH: ca. 7
- pH adjusted: no
- Aeration: vessels were aerated with purified, CO2-scrubbed, moitened air
- Suspended solids concentration: 25 mg/L inoculum
- Continuous darkness: not stated
- Other:

TEST SYSTEM
- Culturing apparatus: 2000 mL SCHOTT Flasks
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: aeration of flasks with CO2 scrubbed air
- Measuring equipment: none attached
- Test performed in closed vessels due to significant volatility of test substance: no
- Test performed in open system: no
- Details of trap for CO2 and volatile organics if used: trapping of CO2 in 0.25 M NaOH. two scrubbers containing 100 mL each.
- Other:

SAMPLING
- Sampling frequency: 10 samples over 28 days
- Sampling method: pipetting 1 mL
- Sterility check if applicable: yes, apparatus blanks
- Sample storage before analysis: no specific storage conditions
- Other:

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: yes
- Toxicity control: yes

STATISTICAL METHODS:
none

Reference substance:

aniline

Preliminary study:

none

Test performance:

no unusual observations

Parameter:

% degradation (CO2 evolution)

Value:

3.7

Sampling time:

2 d

Parameter:

% degradation (CO2 evolution)

Value:

9.7

Sampling time:

4 d

Parameter:

% degradation (CO2 evolution)

Value:

19.8

Sampling time:

7 d

Parameter:

% degradation (CO2 evolution)

Value:

29.7

Sampling time:

9 d

Parameter:

% degradation (CO2 evolution)

Value:

36.1

Sampling time:

11 d

Parameter:

% degradation (CO2 evolution)

Value:

43.2

Sampling time:

15 d

Parameter:

% degradation (CO2 evolution)

Value:

50.9

Sampling time:

18 d

Parameter:

% degradation (CO2 evolution)

Value:

59.5

Sampling time:

23 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

64.5

Sampling time:

29 d

Details on results:

Te 10-day-window began on day 4, at its end, 42 % degradation were reached, missing the pass level of 60 % given in the OECD guideline.
Because the test item is a mixture (i.e. UVCB), the 10-day window has not to be taken into accoung. Degradation surpassed 60 % within 28 days.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable, but failing 10-day window

Conclusions:

The test item Nomcort SG is considered as "ready biodegradable".

Executive summary:

The test item Nomcort SG was tested using a concentration of nominally 20 mg organic carbon/L (corresponging to 25.8 mg Nomcort SG/L) in test medium following OECD 301B and EU-Method C.4 -C. Aniline was chosen as positive control.

Activated sludge was used as inoculum (concentration in the test 25.0 mg dry matter/L). The test was left running for 28 days.

All validity criteria were met. Degradation of the poistive control was 65 % after 9 days.

The following data were determined for the test item Nomcort SG:

10-day window day 4 -14

degradation at the end of 10-day window 42 %

degradation at the end of the test 65 %

pass level following guideline: 60 % at the end of 10-day window for pure substance respective 60 % at the end of the test for mixtures.

Because the test item is a mixture, the 10 -day window has not to be taken into account. As degradation surpassed 60 % in the course of the test, Nomcort SG is considered as readily biodegradable.

Description of key information

one OECD Guideline study available

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable but failing 10-day window