Coconut oil, hydrogenated

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:

From Oct. 9, 2009 to Dec. 11, 2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study was conducted according to standard guidelines (with GLP)

Justification for data waiving:

other:

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Glycerides, C8-18 and C18-unsatd.

EC Number:

266-946-3

EC Name:

Glycerides, C8-18 and C18-unsatd.

Cas Number:

67701-28-4

IUPAC Name:

Glycerides, C8-18 and C18-unsatd.

Details on test material:

- Name of test material (as cited in study report): Fully hydrogenated coconut oil (CAS N° 84836-98-6, EC N° 284-283-8); under the SDA nomenclature, the name of this substance is ‘Glycerides, C8-18, C18 unsaturated’
- Physical state: Solid (bright yellow)
- Expiration date of the lot/batch: December 26, 2009
- Storage condition of test material: In original container, at room temperature (10-30 °C), in the dark

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Not applicable

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: Municipal sewage treatment plant (Rossdorf, Germany)
- Preparation of inoculum for exposure: The activated sludge was washed by repeated centrifugation and re-suspension in tap water. The sediment of the last washing re-suspended in test medium and aerated until use.
- Pretreatment: The washed activated sludge was pre-conditioned in test medium for a maximum of 7 d
- Concentration of sludge: 1.5 g dry material per L of test medium

Duration of test (contact time):

ca. 28 d

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: 85 mg KH2PO4, 217.5 mg K2HPO4, 334 mg Na2HPO4 x 2 H2O, 5 mg NH4Cl, 22.5 mg MgSO4 x 7 H2O, 36.4 mg CaCl2 x 2 H2O and deionised water up to 1000 mL volume
- Test temperature: 22 ± 1 °C
- pH: 7.4 ± 0.2
- Continuous darkness: Yes
- Other: Continuous stirring of test flasks in climatic chamber


TEST SYSTEM
- Culturing apparatus: Manometric test system with test flasks containing a volume of approximately 500 mL
- Number of culture flasks/concentration: Duplicate
- Measuring equipment: Pressure decrease (to determine oxygen consumption) measured using BSB Sensomat system, Aqualytic Dortmund
- Test performed in closed vessels: Yes (closed gas-tight by a measuring head)
- Details of trap for CO2 if used: Evolved carbon dioxide was absorbed in an aqueous solution (45%) of potassium hydroxide.

SAMPLING
- Sampling frequency: Day 0 and 28 (for analysis of nitrate and nitrite using ion chromatography)
- Sampling method: Sufficient aliquot was withdrawn from the bottles containing the test item and inoculum, from the inoculum control and from the toxicity control (after measurement of oxygen concentration).
- Sample storage before analysis: (≤-10 °C)

CONTROL AND BLANK SYSTEM
- Inoculum blank: Yes (duplicate)
- Abiotic sterile control: Yes (single)
- Toxicity control: Yes (single)
- Other: Procedure control (single)

Reference substance

Reference substance:

benzoic acid, sodium salt

Remarks:

ThOD: 1.666 mg oxygen per mg

Results and discussion

% Degradation

Parameter:

% degradation (O2 consumption)

Value:

65

Sampling time:

1 d

Remarks on result:

other: 10-d window failed

Details on results:

- The 10 day window failed.

- The difference of the duplicate values for the degradation of the test item and the plateau, at the end of the test and at the end of the 10 d window, was less than 20%

- The test item contains little amounts of nitrogen, therefore the evaluation of biodegradation has to be based on the assumption that nitrification occurred, in the following expressed as ThODNO3.

However, the nitrate concentration in the test item treated vessels was below LOQ. Therefore, no nitrification occurred.

If no nitrification is considered, the mean biodegradation was also 65% after 28 days of incubation (ThODNH4), still failing the 10-d window.

BOD5 / COD results

Results with reference substance:

The reference item sodium benzoate was sufficiently degraded to 90% after 14 days and to 98% after 28 days of incubation, thus confirming the suitability of the aerobic activated sludge inoculum used

Any other information on results incl. tables

In the toxicity control containing both, the test item and the reference item sodium benzoate, 52% biodegradation was noted within 14 days based on ThOD_NH4and ThOD_NO3respectively. After 28 days of incubation a degradation of 51% were measured.

Thus, the test item can be assumed to be not inhibitory to the aerobic activated sludge microorganisms.

For more details on the results, see table 1 - 4 and figure 1 - 2 under the window 'attached background material'.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable, but failing 10-day window

Conclusions:

Under the test conditions, fully hydrogenated coconut oil was determined to be readily biodegradable, but failed the 10-d window.

Executive summary:

A study was conducted to determine the ready biodegradability of fully hydrogenated coconut oil according to OECD Guideline 301F and EU Method C4 -D.

Fully hydrogenated coconut oil was exposed to aerobic activated sludge from the aeration tank of a domestic waste water treatment plant for 28 days. The biodegradation was followed by the oxygen uptake of the micro organisms during exposure. As a reference item sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control.

Considering that fully hydrogenated coconut oil contains little amount of nitrogen, the nitrate concentration was measured. However, the nitrate concentration in the test item treated vessels was below LOQ. Therefore, no nitrification occurred.

The reference item was degraded to more than 60% after 3 d of incubation.

Under the test conditions, fully hydrogenated coconut oil was determined to be readily biodegradable, but failed the 10-d window.