Glycerides, C16-22

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

From Nov. 04, 2009 to Dec. 02, 2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

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, C16-22

EC Number:

268-083-8

EC Name:

Glycerides, C16-22

Cas Number:

68002-70-0

Molecular formula:

Triglyceride containing a glycerol backbone esterified to fatty acids with a chain length varying from C16 to C22

IUPAC Name:

Tri (C16-22 fatty acyl) glycerol

Details on test material:

- Name of test material (as cited in study report): Fully hydrogenated high erucic acid rapeseed oil (CAS N° 84681-71-0, EC N° 283-532-8); under the SDA nomenclature, the name of this substance is ‘Glycerides, C16-22’
- Physical state: Solid (white yellow)
- Expiration date of the lot/batch: December, 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 litre 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, FeCl3 x 6H2O and deionised water up to 1000 mL volume
- Test temperature: 22 ± 1 °C
- pH: 7.4 ± 0.2 (pH-electrode WTW pH 340i)
- 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: Potassium hydroxide solution (45%) was used for trapping the produced carbone dioxide

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:

29

Sampling time:

1 d

Remarks on result:

other: None

Details on results:

- The 10 day window failed.

- Since the biodegradation did not reach the pass criterion of 60% degradation and no 10 day-window could be determined, the validity criterion was not applicable. At the end of the experiment, the difference in replicate variation was 0%.

- 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 nitrification was not determined by means of an analytical method because the biodegradation rate was not higher than 60% based on ThODNH4

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 degraded to more than 60% after 3 days of incubation. It was degraded to 90% after 14d and to 98% after 28d of incubation.

Any other information on results incl. tables

Inoculum control: The oxygen demand of the inoculum control (medium and inoculum) was 25 mg O2/L and thus not greater than 60 mg O2/L within 28 d as required by the test guideline.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Under the test conditions, fully hydrogenated high erucic acid rapeseed oil was determined to be not readily biodegradable.

Executive summary:

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

Fully hydrogenated high erucic acid rapeseed 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 high erucic acid rapeseed oil contains little amount of nitrogen, the nitrate concentration was measured. However, the nitrification was not determined by means of an analytical method because the biodegradation rate was not higher than 60% based on ThODNH4.

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

Under the test conditions, fully hydrogenated high erucic acid rapeseed oil was determined to be not readily biodegradable.