Glycerides, rape-oil mono-, di- and tri-, hydrogenated

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:

5 Jun- 3 Jul 1991

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test study comparable to guideline with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

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

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: Sewage treatment plant Hochdahl, Germany
- Concentration of sludge: 1 drop sewage effluent/L cultivation solution

Duration of test (contact time):

28 d

Initial conc.:

2 mg/L

Based on:

test mat.

Initial conc.:

5 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral nutrient solution
- Test temperature: 20 °C

TEST SYSTEM
- Culturing apparatus: glass bottles
- Number of culture flasks/concentration: 8

SAMPLING
- Sampling frequency: samples were collected at days 7, 14, 21 and 28

CONTROL AND BLANK SYSTEM
- Inoculum blank: contains inoculated mineral nutrient solution
- Abiotic control: control sample with dilution water only
- References substance control

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

65

Sampling time:

7 d

Remarks on result:

other: 2 mg test substance/L

Parameter:

% degradation (O2 consumption)

Value:

48

Sampling time:

7 d

Remarks on result:

other: 5 mg test substance/L

Parameter:

% degradation (O2 consumption)

Value:

95

Sampling time:

28 d

Remarks on result:

other: 2 mg test substance/L

Parameter:

% degradation (O2 consumption)

Value:

69

Sampling time:

28 d

Remarks on result:

other: 5 mg test substance/L

Details on results:

The test substance reached 95 (replicate containing 2 mg/L) and 69% (replicate containing 5 mg/L) biodegradation after 28 days, fulfilling the 10-d window criterion. Therefore, it can be considered readily biodegradable

Results with reference substance:

Sodium benzoate reached 89% biodegradation within 14 days, fulfilling the validity criterion (>60%)

Table 1. Biodegradability in closed bottle test

Biodegradability in closed bottle test
Compound	COD mg O2/g test substance	Test conc. mg test substance/L	% BOD / COD after days
			7	14	21	28
Sodium benzoate	1670	2	76	89	87	90
Test substance I	2584	2	65	84	91	95
Test substance II	2584	5	48	69	70	69

Interpretation of results:

readily biodegradable

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

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

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
Biodegradation data from a structurally related source substance (Glycerides, C14-18 and C16-18 unsatd. mono- and di-, CAS 67701-33-1) are used as read-across in accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.5. Both are UVCB substances, formed from the esterification of fatty acids and glycerol, having a high content of C18 fatty acids and to a certain extent C14 and C16 fatty acids. Both are composed of mono- to tri esters (Target substance: monoester: 61.9%, diester<: 29.7%, triester: 3.2%; Source substance: monoester: 30 -65%, diester: 20 -50%, triester: 4 -15%). Furthermore, their water solubilities are comparable (< 1 mg/L). Therefore, these two substances are expected to show similar degradation by activated sludge. Based on the above information, the use of data from Glycerides, C14-18 and C16-18 unsatd. mono-, di- and tri- as read-across for Glycerides, C14-18 mono- and di- is considered justified.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (O2 consumption)

Value:

95

Sampling time:

28 d

Remarks on result:

other: 2 mg test substance/L

Key result

Parameter:

% degradation (O2 consumption)

Value:

69

Sampling time:

28 d

Remarks on result:

other: 5 mg test substance/L

Details on results:

The test substance reached 95 (replicate containing 2 mg/L) and 69% (replicate containing 5 mg/L) biodegradation after 28 days, fulfilling the 10-d window criterion. Therefore, it can be considered readily biodegradable

Interpretation of results:

readily biodegradable

Description of key information

Readily biodegradable: 69-95% in 28 days (equivalent to OECD 301D, read across)

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

No study investigating the ready biodegradability of Glyceride, rape oil mono-, di- and tri-, hydrogenated (CAS 91744-94-4) is available. Therefore, biodegradation data from a structurally related source substance (Glycerides, C14-18 and C16-18 unsatd. mono- and di-, CAS 67701-33-1) are used as read-across in accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.5. Both are UVCB substances, formed from the esterification of fatty acids and glycerol, having a high content of C18 fatty acids and to a certain extent C14 and C16 fatty acids. Both are composed of mono- to tri esters (Target substance: monoester: 61.9%, diester<: 29.7%, triester: 3.2%; Source substance: monoester: 30 -65%, diester: 20 -50%, triester: 4 -15%). Furthermore, their water solubilities are comparable (< 1 mg/L). Therefore, these two substances are expected to show similar degradation by activated sludge. Based on the above information, the use of data from Glycerides, C14-18 and C16-18 unsatd. mono-, di- and tri- as read-across for Glycerides, C14-18 mono- and di- is considered justified.

The biodegradation study with the source substance was conducted according to a method equivalent to OECD Guideline 301D, under GLP conditions. Activated sludge was exposed to the test substance for 28 days at 20°C, and biodegradation measured by O2consumption. After 28 days, the test substance reached 95% (2 mg/L test concentration) and 69% (5 mg/L test concentration) biodegradation. Therefore, Glycerides, C14-18 mono- and di- is readily biodegradable. Based on the suitability of the read across approach this is also considered to be true for the target substance.