Fatty acids C16-18 (even numbered), mono and di esters with Sucrose

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
Vega version 1.1.3

2. MODEL (incl. version number)
Ready Biodegradability Model (IRFMN) v. 1.0.9

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
See “Test material information”

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached information on the model provided by the developer. Further information on the OECD criteria as outlined by the applicant is provided below under "Any other information of materials and methods incl. tables"

5. APPLICABILITY DOMAIN
See attached information and information as provided in "Any other information on results incl. tables".

6. ADEQUACY OF THE RESULT
See assessment of adequacy as outlined in the "Overall remarks, attachments" section.

Principles of method if other than guideline:

- Software tool(s) used including version: Vega v1.1.3

- Model(s) used: Ready biodegradability model (version 1.0.9)
Full reference and details of the used formulas can be found in:
Meylan W.M., Howard P.H., Boethling R.S. et al. Improved Method for Estimating Bioconcentration / Bioaccumulation Factor from Octanol/Water Partition Coefficient. 1999, Environ. Toxicol. Chem. 18(4): 664-672

- Model description: see field 'Justification for non-standard information', 'Attached justification' and 'any other information on Material and methods'

- Justification of QSAR prediction: see field 'Justification for type of information', 'Attached justification' and/or 'overall remarks'

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Remarks on result:

readily biodegradable based on QSAR/QSPR prediction

For detailed information on the results please refer to the attached report.

Validity criteria fulfilled:

not applicable

Interpretation of results:

readily biodegradable

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

other: ISO 9439: Evaluation in an aqueous medium of the "ultimate" aerobic biodegradability of organic compounds

GLP compliance:

no

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): Sewage treatment plant RWZI Weurt, The Netherlands

Duration of test (contact time):

28 d

Initial conc.:

30 mg/L

Based on:

TOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: according to guideline
- Test temperature: 20-25 °C
- Aeration of dilution water:
- Suspended solids concentration: 30 mg activated sludge solids/L
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 2 L test vessels
- Number of culture flasks/concentration: 2
- Measuring equipment: The carbon dioxide produced was quantified by titration with hydrochloric acid solution.

SAMPLING
- Sampling frequency: On day 1, 5, 12, 16, 23 and 28

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, two bottles
- Abiotic sterile control: no
- Toxicity control: no
- Other: Reference substance: yes, two bottles

Reference substance:

acetic acid, sodium salt

Parameter:

% degradation (CO2 evolution)

Value:

56.4

Sampling time:

28 d

Remarks on result:

other: Substance A; Mean of two replicates

Parameter:

% degradation (CO2 evolution)

Value:

79.1

Sampling time:

28 d

Remarks on result:

other: Substance B; Mean of two replicates

Results with reference substance:

The reference substance was degraded to 50.1% after 12 d and 60.95% after 16 d. No information is available if the degradation passed the 60% level of degradation after 14 d.

Table 1: Degradation of the two test items and the reference substance

Substance	Biodegradation [%]						Mean [%]
	Day 1	Day 5	Day 12	Day 16	Day 23	Day 28
A_Repl. 1	0.2	20.7	35.2	58.5	66.4	70.0	58.85
A_Repl. 2	0.0	11.8	18.1	32.9	38.1	47.7
B_Repl. 1	2.4	31.8	52.1	68.7	74.8	79.2	79.05
B_Repl. 2	3.8	30.5	49.8	68.9	74.1	78.9
Reference_Repl. 1	2.3	34.6	48.8	61.5	64.2	68.0	68.05
Reference_Repl. 2	1.8	39.1	51.4	60.7	64.3	68.1

Validity criteria fulfilled:

not specified

Remarks:

The validity criteria stipulated in the OECD Guideline cannot be checked completely since information are missing.

Interpretation of results:

readily biodegradable

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Return sludge from Kogasaki municipal sewage treatment plant (date of receipt 06 Aug 1992)

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

DOC removal

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: according to guideline
- Test temperature: 24 - 26 °C
- pH: 6.4 - 7.0

TEST SYSTEM
- Culturing apparatus: Closed system oxygen consumption measuring apparatus
- Number of culture flasks/concentration: 3
- Measuring equipment: Closed system oxygen consumption measuring apparatus (Ohkura Electric Co.); DOC was measured in the supernatant after centrifulation (1000 xg, 10 min); DOC was measured using a TOC analyzer
- Test performed in closed vessels: yes

SAMPLING
- Sampling frequency: BOD was measured continuously; DOC was measured at test end
- Sampling method: For the DOC measurement 10 mL of test solution were removed at test end (centrifuged at 1000 xg for 10 min).

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, one bottle
- Abiotic sterile control: no
- Toxicity control: no
- Other: reference substance: yes, one bottle

Reference substance:

aniline

Parameter:

% degradation (O2 consumption)

Value:

85.7

Sampling time:

28 d

Remarks on result:

other: Mean of three replicates

Parameter:

% degradation (DOC removal)

Value:

99

Sampling time:

28 d

Remarks on result:

other: Mean of three replicates

Results with reference substance:

The reference substance was degraded to 58% after 14 d and 60% after 28 d based on O2 consumption.

Table 1: Biodegradation of the test item and reference substance base on BOD

Bottle No.	ThOD [mg]	Degradability based on BOD
		Day 7		Day 14		Day 21		Day 28
		BOD [mg]	% degradation	BOD [mg]	% degradation	BOD [mg]	% degradation	BOD [mg]	% degradation
1	90.2	44.2	48	54.5	58	56.7	60	58.2	60
2	-	1.3	-	2.5	-	3.0	-	3.7	-
3	60.2	28.3	45	41.4	65	50.6	79	56.1	87
4	60.2	28.1	45	41.4	65	51.9	81	56.2	87
5	60.2	27.9	44	40.9	64	49.3	77	53.4	83
6	60.2	0.0	-	0.0	-	0.0	-	0.5	-

1: Reference substance

2: Activated sludge + basal medium

3 -5: Test substance

6: Test substance + deionized water

Validity criteria fulfilled:

not specified

Remarks:

Fulfilment of validity criteria not indicated in the report.

Interpretation of results:

readily biodegradable

Description of key information

The substance is readily biodegradable according to the OECD criteria.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

The biodegradation of the substance was assessed in a Weight-of-Evidence approach. Two experimental studies and QSAR calculations were assessed for a final conclusion.
The first study was performed according to OECD 301B using domestic activated sludge as inoculum. The initial test substance concentration of 30 mg/L was degraded by 56.4% (replicate A) and by 79.1% (replicate B) after 28 d. Formally the validity criteria of the guideline are not met since the difference in degradation slightly exceeds the limit of 20%. However, the mean degradation value of 68.95% serves as indication that the substance is readily biodegradable according to the OECD criteria.

A second experimental study is available which was performed according to OECD 301C. DOC removal and O2 consumption were followed for 28 d in order to assess the ready biodegradability of the substance. The activated sludge was obtained from a sewage treatment plant treating predominantly domestic sewage. After 28 d the substance was degraded by 85.7% based on O2 consumption and by 99% based on DOC removal.The available data do not allow assessing the 10-day window criterion. However, since the substance is a UVCB substance and consists of structurally similar constituents with e.g. different chain-lengths, degree and/or site of branching or stereo-isomers], sequential (instead of concurrent) biodegradation of the individual structures can take place, but all constituent can be considered as readily biodegradable. Thus, referring to Annex I of the OECD Guideline for Testing of Chemicals ‘Revised introduction to the OECD guidelines for testing of chemicals, section 3’ (OECD, March 2006), the 10-day window should not be considered for this UVCB substance and due to a degradation of >60 % within 28 days the substance can be regarded as readily biodegradable.
The results of the experimental studies is further supported by reliable QSAR calculations for representative constituents of the UVCB substance (VEGA 1.1.3, Ready biodegradability model v1.0.9). Based on this result all constituents are considered to be readily biodegradable.
All information (experimental and QSAR) give clear evidence that the substance is readily biodegradable according to the OECD criteria.