Fatty acids, C12-14 (even numbered), methyl ester

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

31 Aug - 28 Sep 1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Circular on Test Methods of New Chemical Substances (Japan), Biodegrability test

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

mixture of sewage, soil and natural water

Details on inoculum:

- Source of inoculum/activated sludge (location, sampling depth): location: 10 sites (4 sewage plants, 3 rivers, 1 lake and 2 bays) around Japan, sampling depth: return sludge in sewage plants, surface water and surface soil of foreshore
- Laboratory culture: Thirty minutes after stopping of aeration, discard about one third of the whole volume of supernatant and add an equal volume of a solution (pH adapted to 7.0 with NaOH) containing 0.1% each of glucose, peptone and pottasium orthophosphate, to the settled material and re-commence aeration. This procedure was repeated once per day.
- Temperature: 25 ± 2 °C
- Concentration of sludge: 30 mg/L

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: recommended medium in the guideline (JIS K 0102-1993)
- Test temperature: 25 ± 1 °C
- Suspended solids concentration: 30 mg/L

TEST SYSTEM
- Culturing apparatus: 300 mL culture bottle
- Number of culture flasks/concentration: 1 (water + test substance), 3 (sludge + test sub.), 1 (sludge + reference sub.), 1 (sludge)
- Measuring equipment: Coulometer
- Test performed in closed vessels due to significant volatility of test substance: Yes
- Details of trap for CO2 and volatile organics if used: soda lime

SAMPLING
- Sampling frequency: 7, 14, 21, 28 days

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: no
- Toxicity control: no

Reference substance:

aniline

Key result

Parameter:

% degradation (O2 consumption)

Value:

78

Sampling time:

28 d

Details on results:

No 10-day window required. Substance was readily biodegradable.
Partial hydrolisation of the test substance in water to form dodecanoic acid and methanol was described.

Results with reference substance:

The oxygen consumption for aniline in the above used test system reached 62% and 75% degradation after 7 days and 14 days.

Table 1. Table of BOD

	7^thday		14^thday		21^stday		28^thday
	BOD (mg)	Deg(%)	BOD (mg)	Deg(%)	BOD (mg)	Deg(%)	BOD (mg)	Deg(%)	MeanDeg. %
Sludge+Aniline	57.4	62	71.0	75	71.5	75	75.0	76
Water + Testsub.	0	-	0.2	-	0.2	-	0.2	-
Controlblank	1.6	-	3.4	-	3.7	-	6.7	-
Sludge+ Testsub.	40.5	46	57.1	64	68.3	77	73.1	79	78
Sludge+ Testsub.	31.3	35	48.2	53	60.1	67	68.3	73
Sludge+ Testsub.	32.3	37	51.7	58	65.5	74	75.3	82

Deg. =( BOD- control blank) / TOD x 100 TOD of test substance: 83.9 mg TOD of aniline: 90.3 mg

 

Table 2.Result of analysis for BOD and GC

		water+ testsub.	sludge+ testsub. (*1)			TheoreticalAmount
		sampleNo. 2	sampleNo. 4	sampleNo. 5	sampleNo. 6
BOD	mg	0.2	66.4	61.6	68.6	83.9
GC (residue of test substance)	mg	26.9	0.0	0.0	0.0	30.4
	% (*2)	89	0	0	0	-
GC (production ofdodecanoicacid)	mg	1.1	0.0	0.0	0.0	28.4
	% (*2)	4	0	0	0	-

(*1) (sludge+ test sub.)was calculated by subtracting blank values.

(*2) Residue and production percentage was calculated as followed.

Residue percentage = Residue amount (mg) /Theoretical amount (mg) x 100

Production percentage = Production amount (mg) /Theoretical amount (mg) x 100

 

Validity criteria fulfilled:

yes

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:

1989

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

yes

Remarks:

adaptations for poorly soluble substances made (BODIS method)

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Sewage treatment plant Hochdahl, municipal sewage, serving a population equivalent of 27000

Duration of test (contact time):

28 d

Initial conc.:

100 other: mg

Based on:

ThOD/L

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Concentration of elements in test medium (according to OECD 301 Guideline)
P 116 mg/L
N 1.3 mg/L
Na 86 mg/L
K 122 mg/L
Mg 2.2 mg/L
Ca 9.9 mg/L
Fe 0.01-0.05 mg/L
- Mineral test medium was inoculated with 2.5-3.5 mL activated sludge, stirred and stabilised for one week. Then, it was distributed at 200 to 300 mL into test bottles, bottles were aerated with compressed air until O2 saturation was reached and then spiked with a pre-determined amount of test material
- Test temperature: 20-25 °C, however since the O2 measurements should be carried out at 20 ± 0.5 °C, the temperature was adjusted half an hour before

TEST SYSTEM
- Culturing apparatus: Bottles with sintered glass tube head
- Number of culture flasks/concentration: 3
- Method used to create aerobic conditions: Compressed air

Reference substance:

acetic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

83

Sampling time:

28 d

Parameter:

% degradation (O2 consumption)

Value:

68

Sampling time:

7 d

Details on results:

The test substance reached 83% degradation on day 28, fulfilling the 10-d window criterion. Therefore, it can be considered readily biodegradable

Results with reference substance:

Sodium acetate reached 93% biodegradation within 14 days and a final biodegradation value of 94% on day 28

Table 1. % Biodegradation measured as O2 consumption of test and reference substance

Day	TS	Ref substance
7	67	86
14	81	93
21	82	94
28	83	94

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Reference 3

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:

Category justification is attached in chapter 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (O2 consumption)

Value:

83

Sampling time:

28 d

Remarks on result:

other: CAS 6788-59-8

Key result

Parameter:

% degradation (O2 consumption)

Value:

78

Sampling time:

28 d

Remarks on result:

other: CAS 111-82-0

Description of key information

Readily biodegradable:

> 70% in 28 days (read across)

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

As no experimental data evaluating the potential for ready biodegradability of Fatty acids, C12-C14 (even numbered), methyl esters (CAS No. 308065-15-8) are available, in accordance to Regulation (EC) No. 1907/2006, Annex XI, 1.5, read-across from structurally related category members, methyl laurate (CAS No. 111-82-0) and Fatty acids, coco, Me esters (CAS No. 61788-59-8) is performed. All three substances are characterized as esters of methanol and either C12 to C14 fatty acids (CAS No. 308065-15-8 and CAS No. 61788-59-8) or only C12 fatty acids (CAS No. 111-82-0). Therefore, their biodegradation potential is expected to be comparable and the read-across is considered justified.

The study evaluating the biodegradation potential of methyl laurate (CAS No. 111-82-0, Japanese Ministry of Economy, Trade and Industry, 1995) was conducted according to OECD 301C (Modified MITI Test), under GLP conditions. A mixture of sewage, soil and natural water was used as inoculum and O2 consumption monitored as indicator of biodegradation. After 28 days of incubation, the test substance reached 78% biodegradation. Since the 10-day window concept does not apply to the MITI method, methyl laurate can be considered readily biodegradable according to OECD criteria. On the other hand, the test investigating the potential for ready biodegradability of Fatty acids, coco, Me esters (CAS No. 61788-59-8, Richterich, 2001) was performed following a method equivalent to OECD Guideline 301D, adapted for poorly soluble substances (BODIS test). This substance reached 83% biodegradation after 28 days, fulfilling the 10-day window criterion (> 60% biodegradation within this period) and therefore it is readily biodegradable too.

Based on the results obtained for the structurally related category members (in accordance to Regulation (EC) No. 1907/2006, Annex XI, 1.5), Fatty acids, C12-C14 (even numbered), methyl esters can be considered as readily biodegradable.