C18 (branched) fatty acids, esters with mono-, di-, and tri-glycerol

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:

2005-05-19 to 2005-06-17

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

C18 (branched) fatty acids, esters with mono-, di-, and tri-glycerol

EC Number:

701-479-5

Molecular formula:

C42H82O7

IUPAC Name:

C18 (branched) fatty acids, esters with mono-, di-, and tri-glycerol

Details on test material:

- Name of test material (as cited in study report): Hostacerin DGI
- Physical state: Liquid, light yellow viscous
- Analytical purity: 100 % (a/a)
- Lot/batch No.: DEGE910173
- Expiration date of the lot/batch: 2006-08-01
- Stability under test conditions: Not applicable
- Storage condition of test material: Room temperature, protected from light and mositure, in original container.

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Municipal sewage treatment plant, D-31137 Hildesheim, Germany
- Pretreatment/Concentration of sludge: The activated sludge was washed twice with autoclaved tap water. After the second washing the settled sludge was resuspended in mineral salts medium and was maintained in an aerobic condition by aeration for 2-4 hours. Thereafter the sludge was homogenized with a blender. The supernatant was decanted and maintained in an aerobic condition by aeration with Co2 free air until test start.
10 mL/L were used to initiate inoculation.
- Initial cell/biomass concentration: 6 * 10E9 CFU/L corresponding to 6 * 10E7 CFU/L in the test vessel

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

20 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral salts medium acc. to OECD 301 B / CO2 Evolution Test
- Test temperature: 22 +/- 2°C (20.0 - 23.0 °C, for 4 h down to 19.5 °C
- pH adjusted: no
- Continuous darkness: no, low light conditions (brown glass bottles)



TEST SYSTEM
- Culturing apparatus: 5000 mL brown glass flasks
- Number of culture flasks/concentration: 1 for the reference item, 1 for toxicity control (test and reference item), 2 for the control, 2 for the test item
- Method used to create aerobic conditions: Aeration with 30 - 100 mL/min
- Measuring equipment: Visual check of aeration twice per day
- Details of trap for CO2 and volatile organics if used: CO2 adsorption vessels were connected to the air outlets of the incubation vessels via a series of 3 gas wash bottles, each containing 100 mL of a 0.0125 mol/L Ba(OH)2 solution.
- Other: Application: The necessary amounts of bidistilled water, mineral salts medium and inoculum were placed in each of the incubation vessels. The vessels were aerated for 24 h with CO2 free air. After 24 h the CO2 adsorption vessels were connected to the air outlets of the incubation vessels. Test and reference item were weighed out and were transferred into the incubation vessels with bidistilled water. The vessels were made up to 3 L with bidistilled water and connected to the system for the production of CO2 free air.


SAMPLING
- Sampling frequency: Backtitration of the residual Ba(OH)2 with 0.05 N HCL was carried out three times a week during the first ten days and thereafter twice weekly.
- Sampling method: For each titration the first gas wash bottle was removed and a new bottle was connected to the last one.



CONTROL AND BLANK SYSTEM
- Inoculum blank: Test medium without test and reference item
- Abiotic sterile control: No
- Toxicity control: Test item and reference item in test concentration



STATISTICAL METHODS:
The theoretical production of carbon dioxide (ThCO2) of the test item and functional control is calculated by the carbon content and the molecular formula, respectively.
The produced CO2 was calculated by: 1 mL HCl (c = 0.05 mol/L) = 1.1 mg CO2
The net amount of CO2 produced is calculated by correcting the results of the test item and functional control for endogenous CO2 production of the inoculum controls.
The biodegradation is calculated from the ratio theoretical CO2 production to net CO2 production.

Reference substance

Reference substance:

acetic acid, sodium salt

Remarks:

20 mg/L

Results and discussion

Preliminary study:

Not performed

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

94

Sampling time:

28 d

BOD5 / COD results

Results with reference substance:

In the toxicity control containing both test and reference item a biodegradation rate of 38 % was determined after 7 days and it came to 90 % after 28 days. The biodegradation of the reference item was not inhibited by the test item in the toxicity control.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test item is classified as readily biodegradable after 28 days within the 10d-window.

Executive summary:

The test item was tested in an OECD 301B CO2 Evolution test and is readily biodegradable after 28 days fulfilling the 10 d-window criteria.

Biodegradation of the Test Item Hostacerin DGI in Comparison
 to the Functional Control and Toxicity Control

	Biodegradation [%]
	Study Day [d]
	6	14	21	28
Test Item, 1^st Replicate	36	75	91	100
Test Item, 2^nd Replicate	21	54	70	88
Functional Control	56	77	80	93
Toxicity Control	30	62	74	89