Decanoic acid, monoester with glycerol

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Please refer to analogue justification provided in Section 13

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Parameter:

% degradation (CO2 evolution)

Value:

79.5

Sampling time:

28 d

Remarks on result:

other: Read across from CAS 91744-28-4

Parameter:

% degradation (CO2 evolution)

Value:

82.6

Sampling time:

28 d

Remarks on result:

other: Read across from CAS 85536-07-8

Interpretation of results:

readily biodegradable

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

4 Sep - 3 Oct 2012

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)

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesanstalt für Umwelt, Messungen und Naturschutz Baden-Württemberg, Karlsruhe, Germany

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 wastewater treatment plant, Breisgauer Bucht, sampled on September 3rd, 2012
- Pretreatment: The activated sludge was washed twice by settling the sludge, decanting the supernatant and re-suspending the sludge in tap water
- Concentration of sludge: 30 mg dry solids per litre (dry solid of the activated sludge was 2.9 g/L by weight measurements after 2 h drying at 110 °C

Duration of test (contact time):

29 d

Initial conc.:

41 - 41.1 mg/L

Based on:

test mat.

Initial conc.:

20 mg/L

Based on:

other: TOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium:
Solution A (per 1 liter demineralised water):
KH2PO4: 8.50 g
K2HPO4: 21.75 g
Na2HPO4 x 2 H2O: 33.40 g
NH4Cl: 0.50 g

Solution B:
CaCL2 x 2 H2O: 36.40 g

Solution C:
MgSO4 x 7 H2O: 22.50 g

Solution D:
FeCL3 x 6 H2O: 0.25 g

For the preparation of the mineral medium 10 mL of solution A is mixed with 800 mL demineralised water, 1 mL each of solutions B, C, and D are added and the volume is made up to 1L.

- Test temperature: 21 - 24 °C

TEST SYSTEM
- Culturing apparatus: Gas wash bottles (2000 mL) with lateral connecting pieces for butyl rubber septums were used as reactors. The liquid volume was fixed as 1500 mL each. Mixing was perfomred by a magnetic stirrer with 2 cm stir bars. The test item was added into the three test vessels. The reference compound was added to the three reference vessels. Reference compound and test item were added to the toxicity control vessel
- Number of culture flasks/concentration: 2 ( 1 flask was not considered due to preparation problems)
- Method used to create aerobic conditions: The CO2-free air production system consits of an air compressor, three 1000 mL gas wash bottles filled with dry soda lime in series followed by one bottle filled with 0.1 M NaOH. At the end of the system is one gas wash bottle filled with demineralised water, followed by an empty one to catch any drops of condensation water. A colour change of the soda lime from white to blue indicates that the CO2 absorption capacity is depleted. The CO2-free air is passed on to an air distributor with two input and 22 output channels and through PE-tubes.
- Test performed in closed vessels due to significant volatility of test substance: yes
- Details of trap for CO2 and volatile organics if used: The CO2 produced in the reactors was absorbed in two 250 mL gas wash bottles in series filled with 200 mL 0.2 M NaOH

SAMPLING
- Sampling method: Through the lateral connecting pieces through the butyl rubber septum using 5 mL PE syringes

CONTROL AND BLANK SYSTEM
- Inoculum blank: 3 flasks
- Toxicity control: 1 flask (5.15 mL of a stock solution of 10 g/L reference substance and 41.1 mg of the test item were added into the vessel. This corresponds to a concentration of 40.0 mg/L organic carbon)
- Reference: 3 flasks (5.15 mL of a stock solution of 10 g/L sodium benzoate was added into the reference vessels. This corresponds to a concentration of 20 mg/L organic carbon)

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (CO2 evolution)

Value:

79.5

Sampling time:

28 d

Details on results:

- The test substance reached 79.5% biodegradation after 28 days and therefore, it is considered as readily biodegradable.

Results with reference substance:

The reference compound sodium benzoate reached the pass level of 60% within 7 days.

The test item had no toxic effect to the inoculum (55% degradation in the toxicity control after 14 days).

Table: Biodegradation after x days in % of ThCO2

	Day 0	Day 4	Day 7	Day 10	Day 14	Day 21	Day 28	Day 29
Test flasks	0	5.4	17.0	26.6	36.6	61.1	79.3	77.6
	0	14.2	38.6	50.8	62.7	77.6	82.0	81.5
Reference flasks	0	55.2	72.4	80.5	80.6	85.3	85.9	85.2
	0	64.1	78.7	85.3	85.3	90.9	90.1	90.2
	0	59.3	75.9	82.2	82.2	87.0	87.5	88.3
Toxicity control	0	27.2	43.1	49.2	55.0	66.5	75.0	77.1

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Since the test item 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 can be considered as readily biodegradable. Thus, referring to Annex I to 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.

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

4 Sep - 3 Oct 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesanstalt für Umwelt, Messungen und Naturschutz Baden-Württemberg, Karlsruhe, Germany

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 wastewater treatment plant, Breisgauer Bucht, sampled on September 3rd, 2012
- Pretreatment: The activated sludge was washed twice by settling the sludge, decanting the supernatant and re-suspending the sludge in tap water
- Concentration of sludge: 30 mg dry solids per litre (dry solid of the activated sludge was 2.9 g/L by weight measurements after 2 h drying at 110 °C

Duration of test (contact time):

29 d

Initial conc.:

46.7 - 47 mg/L

Based on:

test mat.

Initial conc.:

20 - 20.1 mg/L

Based on:

other: TOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium:
Solution A (per 1 liter demineralised water):
KH2PO4: 8.50 g
K2HPO4: 21.75 g
Na2HPO4 x 2 H2O: 33.40 g
NH4Cl: 0.50 g

Solution B:
CaCL2 x 2 H2O: 36.40 g

Solution C:
MgSO4 x 7 H2O: 22.50 g

Solution D:
FeCL3 x 6 H2O: 0.25 g

For the preparation of the mineral medium 10 mL of solution A is mixed with 800 mL demineralised water, 1 mL each of solutions B, C, and D are added and the volume is made up to 1L.

- Test temperature: 21 - 24 °C

TEST SYSTEM
- Culturing apparatus: Gas wash bottles (2000 mL) with lateral connecting pieces for butyl rubber septums were used as reactors. The liquid volume was fixed as 1500 mL each. Mixing was perfomred by a magnetic stirrer with 2 cm stir bars. The test item was added into the three test vessels. The reference compound was added to the three reference vessels. Reference compound and test item were added to the toxicity control vessel
- Number of culture flasks/concentration: 3
- Method used to create aerobic conditions: The CO2-free air production system consits of an air compressor, three 1000 mL gas wash bottles filled with dry soda lime in series followed by one bottle filled with 0.1 M NaOH. At the end of the system is one gas wash bottle filled with demineralised water, followed by an empty one to catch any drops of condensation water. A colour change of the soda lime from white to blue indicates that the CO2 absorption capacity is depleted. The CO2-free air is passed on to an air distributor with two input and 22 output channels and through PE-tubes.
- Test performed in closed vessels due to significant volatility of test substance: yes
- Details of trap for CO2 and volatile organics if used: The CO2 produced in the reactors was absorbed in two 250 mL gas wash bottles in series filled with 200 mL 0.2 M NaOH

SAMPLING
- Sampling method: Through the lateral connecting pieces through the butyl rubber septum using 5 mL PE syringes

CONTROL AND BLANK SYSTEM
- Inoculum blank: 3 flasks
- Toxicity control: 1 flask (5.15 mL of a stock solution of 10 g/L reference substance and 46.9 mg of the test item were added into the vessel. This corresponds to a concentration of 40.1 mg/L organic carbon)
- Reference: 3 flasks (5.15 mL of a stock solution of 10 g/L sodium benzoate was added into the reference vessels. This corresponds to a concentration of 20 mg/L organic carbon)

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (CO2 evolution)

Value:

82.6

Sampling time:

28 d

Details on results:

- The test substance reached 82.6% biodegradation after 28 days and therefore, it is readily biodegradable.
- Biodegradation in the toxicity control reached 81.1% within 14 days, clearly indicating the lack of toxicity of the test item to activated sludge microorganisms.

Results with reference substance:

The reference compound sodium benzoate reached the pass level (60% biodegradation) for ready biodegradability within 7 days.

The test item had no toxic effect to the inoculum (81.1% degradation in the toxicity control after 14 days).

Table 1: Biodegradation after x days in % of ThCO2

	Day 0	Day 3	Day 7	Day 10	Day 14	Day 21	Day 28	Day 29
Test flasks	0	43.3	65.7	78.1	77.8	82.9	86.8	84.5
	0	42.4	64.8	76.4	77.1	82.5	84.1	83.5
	0	37.7	60.4	71.1	74.4	78.8	82.2	79.7
Reference flasks	0	55.2	72.4	80.5	80.6	85.3	85.9	85.2
	0	64.1	78.7	85.6	85.3	90.9	90.1	90.2
	0	59.3	75.9	82.4	82.2	87.0	87.5	88.3
Toxicity control	0	41.6	63.9	73.8	81.1	84.6	89.0	87.1

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Additional information

Since no studies investigating the biodegradation in water of Esterification product of glycerol and C8-C12 (even numbered) fatty acids (no CAS) are available, in accordance with Regulation (EC) No 1907/2006 Annex XI, 1.5, a read-across to the structurally related source substances Glycerides, C12-18 di- and tri- (CAS 91744-28-4) and Glycerides, C8-10 mono- and di- (CAS 85536-07-8) was conducted. The source substances are representative to evaluate the biodegradation in water of the target substance.

The target substance Esterification product of glycerol and C8-C12 (even numbered) fatty acids (no CAS) is a UVCB substance characterized by the alcohol component glycerol which is esterified with C8, C10 and C12 fatty acids.

The source substance Glycerides, C12-18 di and tri (CAS 91744-28-4) is characterized by the alcohol component glycerol and C12-18 fatty acids.

The source substance Glycerides, C8-10 mono- and di- (CAS 85536-07-8) is a UVCB substance characterized by the alcohol component glycerol which is esterified by C8 and 10 fatty acids.

This read-across is justified in detail within the analogue justification in IUCLID section 13. In this case of read-across, the two best suited (highest degree of structural similarity, nearest physico-chemical properties) read-across substances were used to provide a best- and worst-case approach to the target substance.

The first study with the read-across substance Glycerides, C12-18 di and tri (CAS 91744-28-4) was conducted according to OECD 301B (GLP) under aerobic conditions using domestic, non-adapted activated sludge from a wastewater treatment plant. The initial test substance concentration was 41.0-41.1 mg/L. A biodegradation rate of 79.5% (CO2 evolution) was observed after 28 days but the 10-day window was not met. Since the test item is a UVCB substance and consists of structurally similar constituents with different chain-lengths, sequential (instead of concurrent) biodegradation of the individual structures can take place, but all can be considered as readily biodegradable. Thus, referring to Annex I to 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 second study with the read-across substance Glycerides, C8-10 mono- and di- (CAS 85536-07-8) was conducted according to OECD 301B (GLP) under aerobic conditions using domestic, non-adapted activated sludge from a wastewater treatment plant. The initial test substance concentration was 46.7-47.0 mg/L. A biodegradation rate of 82.6% (CO2 evaluation) was observed after 28 days meeting the 10-day window. Thus, the substance is readily biodegradable according to the OECD criteria.

Based on the structurally related read-across substances (in accordance with Regulation (EC) No 1907/2006 Annex XI, 1.5) which are characterized by a similar ecotoxicological profile and comparable structure, it can be concluded that the target substance Esterification product of glycerol and C8-C12 (even numbered) fatty acids (no CAS) is readily biodegradable.