Fatty acids, coco, esters with 1,3-butanediol

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:

25 Oct - 12 Dec 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Version / remarks:

1992

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Valence’s Waste treatment Plant (collected on 26th October 2017)
- Pretreatment: The sludge was settled and the liquid supernatant discarded. The concentrated sludge was then suspended in the mineral solution. These two steps were repeated twice.
- Concentration of sludge: The concentration of suspended solids was determined after rinsing the sludge. An activated sludge volume was filtered on a 1.2 μm filter with a vacuum pump. Then, the filter
was dried in drying oven at 105 °C. Solid matter was 4.52 g/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: according to the guideline
- Additional substrate: no
- Solubilising agent (type and concentration if used): no
- Test temperature: 20.5 ° C ± 1
- pH: 7.5 - 7.8 (at Day 0 and 28)
- Continuous darkness: yes
- Other: The flasks were closed with the measuring heads and stirred with a magnetic stirrer.

TEST SYSTEM
- Culturing apparatus: 650 mLwhite glass bottles
- Number of culture flasks/concentration: 2
- Measuring equipment: heads and oxitop® controller
- Details of trap for CO2: The CO2 released was trapped by soda pellets.

SAMPLING
- Sampling frequency: on days 0, 1, 2, 3, 4, 6, 9, 13, 20, 28
- Sampling method: Oxygen consumption was measured by decreasing of the pressure in the bottles. The Biological Oxygen Demand values were extracted from the measurement heads.

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 replicates (250 mL tes media + 1.7 mL inoculum)
- Reference control: 2 replicates (250 mL test media + 26.3 mL reference item + 1.7 mL inoculum)
- Abiotic control: 1 replica (23.2 mL test item + 250 mL media)
- Toxicity control: 1 replica (23.1 mg test item + 24.4 mg reference substance + 250 mL media + 1.7 mL inoculum)

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

60.1

Sampling time:

28 d

Details on results:

57.7 % biodegradation took place in the toxicity control within 13 d and therefore the test item was not toxic to micro-organisms.
The degradation of test item was not abiotic as the abiotic control revealed.

Results with reference substance:

> 60% biodegradation of the reference substance took place within 14 d (61.35% in 4 days)

The results were retrospectively to the study report recalculated and corrected by the laboratory and documented in the amendment N°02 to final report GLP study RRCo-000104_01. These results are presented below:

BIOLOGICAL RESULTS:

Table 1: % Biodegradation of reference control, test item, toxicity control and abiotic control.

Time (Days)	Reference control A	Reference control B	Test item solution A	Test item solution B	Toxicity control	Abiotic control
0	0	0	0	0	0	0
0.5	0	0	0.7	1.5	0.5	5.3
1	10.5	9.8	7.4	8.5	7.6	4.5
2	36.4	38	14.1	14.7	12.9	3.8
3	48.1	47.8	18	19.5	16.4	4.5
4	61.8	60.9	22.6	23.6	21.3	4.1
6	76.2	73.5	27.5	29.4	45.4	4.5
9	81.4	80.8	34.5	35.9	52.6	4.5
13	84.9	83.8	41.1	42.1	57.7	4.1
20	89	91.7	52.5	54	72.4	3.7
28	90.2	92.9	59.2	60.9	82.5	4.1

VALIDITY CRITERIA:

Table 2: Validity criteria for OECD 301.

Criterion from the guideline	Outcome	Validity criterion fulfilled
Difference of extremes of replicate values of the removal of the test chemical at the plateau, at the end of the test or at the end of the 10-d window, as appropriate, is less than 20%.	Difference of extremes 1.1%	yes
Percentage degradation of the reference compound has reached the pass levels by day 14.	61.35 % by Day 4	yes
The oxygen uptake of the inoculum blank is normally 20-30 mg O2/L and should not be greater than 60 mg/L in 28 days.	22.1 mg O2/L in 28 d	yes
The toxicity control should degrade to at least 35% (based on DOC) or at least 25% (based on ThOD or ThCO2) within 14 d.	57.7 % by Day 13	yes
The pH value should be in the range 6-8.5 in the test vessel, if the oxygen consumption by the test substance is less than 60% and the pH value is outside the range 6-8.5, the test should be repeated with a lower concentration of test substance.	pH between 7.5 and 7.8	yes

Validity criteria fulfilled:

yes

Remarks:

For further details please refer to “Any other information on results incl. tables”.

Interpretation of results:

readily biodegradable

Description of key information

Readily biodegradable (60.1 % degradation after 28 d, OECD 301F)

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

One study is available in which the biodegradability of fatty acids, coco, esters with 1,3-butanediol (CAS 73138-39-3) was tested. The study was conducted according to the OECD guideline 301 F and GLP. Non-adapted activated sludge was used as inoculum and was exposed to 100 mg/L test material for 28 d. Oxygen consumption was measured by decreasing of the pressure in the bottles on days 0, 1, 2, 3, 4, 6, 9, 13, 20 and 28 in order to monitor the biodegradation of the substance. A reference and a toxicity control were run in parallel. The substance was found to biodegrade rapidly. 60.1% biodegradation was recorded after 28 d and therefore the substance is regarded as readily biodegradable. All validity criteria mentioned by the guideline were fulfilled. 57.7% biodegradation took place in the toxicity control within 13 d and therefore the test item was not toxic to micro-organisms.