2-hydroxy-3-(oleoyloxy)propyl 5-oxo-L-prolinate

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12 Nov - 11 Dec 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2014

Report date:

2014

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Version 1992

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Version / remarks:

Version 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Hessisches Ministerium für Umwelt, Energie, Landwirtschaft und Verbraucherschutz, Wiesbaden, Germany

Test material

Test material information

Constituent 1

Reference substance name:

2-hydroxy-3-(oleoyloxy)propyl 5-oxo-L-prolinate

EC Number:

283-393-3

EC Name:

2-hydroxy-3-(oleoyloxy)propyl 5-oxo-L-prolinate

Cas Number:

84608-82-2

Molecular formula:

C26H45NO6

IUPAC Name:

2-hydroxy-3-(oleoyloxy)propyl 5-oxo-L-prolinate

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Aerobic activated sludge (microorganisms from a domestic wastewater treatment plant) was supplied by the sewage works of Rossdorf, Germany.
- Preparation of inoculum for exposure: The aerobic activated sludge was washed by centrifugation and the supernatant liquid phase was decanted. The solid material was resuspended in tap water and centrifuged again. This procedure was done three times. An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge to its dry weight was determined. Based on this ratio, calculated aliquots of washed sludge suspension, corresponding to 3.5 g dry material
per litre were mixed with test water. This suspension was used for the experiment.
- Concentration of sludge: 28.7 mg/L

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

104.1 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

238.6 mg/L

Based on:

other:

Remarks:

ThOD NH4

Initial test substance concentration 3

Initial conc.:

252.9 mg/L

Based on:

other:

Remarks:

ThOD NO3

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: according to guideline
- Solubilising agent: For a better distribution of the test item, silicone oil AR20 with a concentration of about 1% was added to the test flasks.
- Test temperature: 22 ± 1°C
- pH: 7.6 (measured at test start); 7.1-7.5 (measured at test end)
- pH adjusted: no
- Continuous darkness: yes

TEST SYSTEM
- Number of culture flasks/concentration: 2 flasks with test item (25.6 and 25.2 mg per flask with 244 mL final volume each)
- Measuring equipment: BSB/BOD-Sensor-System, Aqualytic Dortmund, Germany. The amount of O2 consumed by the activated sludge was calculated from the decrease of pressure in the reaction vessel. The change of pressure in the test flasks was measured by means of a manometric method (BSB/BOD-Sensor-System) each day.
- Test performed in closed vessels: The test flasks were closed gas-tight by a measuring head.
- Details of trap for CO2 and volatile organics: Potassium hydroxide solution (45%) was used for trapping the produced carbon dioxide.

SAMPLING
- Sampling frequency and method: Samples were taken every day from both test flasks, the toxicity and the reference control.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 2 flasks
- Abiotic control: yes, 1 flask (25.0 mg test item per flask with 246.4 mL final volume)
- Toxicity control: yes, 1 flask (25.5 mg test item and 25.3 mg reference item per flask with 244 mL final volume)
- Reference control: yes, 1 flask (25.2 mg reference item per flask with 244 mL final volume)

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (O2 consumption)

Value:

80

Sampling time:

28 d

Remarks on result:

other: based on ThOD NH4

% Degradation 2

Parameter:

% degradation (O2 consumption)

Value:

76

Sampling time:

28 d

Remarks on result:

other: based on ThOD NO3

Details on results:

The mean biodegradation percentage based on ThOD NO3 at the end of the 10-day window was 70%; the criterion of the 10 day window was passed. Nitrogen is part of the molecular structure of the test item; therefore nitrification (ThOD NO3) was considered for the evaluation of results.

The toxicity control reached 58% degradation after 14 days. The substance is therefore not considered inhibitory to microorganisms.

BOD5 / COD results

Results with reference substance:

The reference item sodium benzoate was sufficiently degraded to 77% after 14 days and to 80% after 28 days of incubation, thus confirming the suitability of the aerobic activated sludge inoculum used.

Any other information on results incl. tables

Table 1:Percentage Biodegradation of Test Item, of Sodium Benzoate and of the Toxicity Control based on ThOD NH4

Time (days)	Percentage Biodegradation
	Test item		Reference substance	Toxicity control
	Flask 1 [%]	Flask 2 [%]	Flask 5 [%]	Flask 7 [%]
1	12	13	32	17
2	19	21	41	25
3	29	32	64	40
4	40	42	67	45
5	48	53	70	50
6	56	61	73	53
7	60	65	73	55
8	67	70	73	56
9	69	72	73	57
10	73	74	76	58
11	72	75	74	59
12	73	76	76	58
13	75	76	76	58
14	74	77	77	58
15	75	78	76	57
16	75	80	76	57
17	77	80	76	57
18	77	80	78	57
19	76	81	77	56
20	78	81	77	56
21	78	83	77	56
22	78	83	77	56
23	78	83	77	56
24	78	83	80	56
25	78	83	80	56
26	80	83	80	56
27	78	81	80	56
28	78	81	80	56

Table 2: Validity criteria

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%.	1.9%	yes
Percentage degradation of the reference compound has reached the pass levels by day 14.	60% reached after 3 days	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.	58%	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.	27.5 mg/L	yes

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

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

Interpretation of results:

readily biodegradable