Olive oil decyl esters

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:

2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Olive oil decyl esters

EC Number:

948-056-3

IUPAC Name:

Olive oil decyl esters

Test material form:

solid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

Specification
Activated sludge from a biologic sewage treatment plant was used as inoculum. The cho-sen plant treats mostly domestic sewage.

Source and Pre-Treatment of inoculum
-Source
The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant, Im Altenschemel, 67435 NW-Lachen-Speyerdorf.
Date of collection: 17. Aug. 2018, batch no: 20180817.
-Pre -Treatment
The sludge was filtrated, washed with test medium (2x) and re-suspended in test medium. It was then aerated until use. The dry matter was determined to contain 5000 mg of sus-pended solids/L.

Duration of test (contact time):

ca. 28 d

Initial test substance concentration

Initial conc.:

ca. 20 mg/L

Based on:

TOC

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

Preparation:
The medium was prepared from the stock solutions. The stock solution of the positive control was prepared and its DOC was measured. The inoculum was taken from its source, washed, aerated and the dry matter was determined.
The test vessels were filled with medium and inoculum. Then, all flasks were aerated for 72 hours with purified, CO2-free, moistened air to purge the system of CO2.

Experimental parameters:
Flask volume 1500 mL
Apparatus blanks 2, containing mineral medium only
Blank Controls 2, containing mineral medium and inoculum
Positive control flasks 2, containing positive control, mineral medium and inoculum
Test flasks 2, containing test item, mineral medium and inoculum
Abiotic control 1, containing test item, mineral medium and HgCl2
Toxicity control 1, containing test item, positive control, mineral medium and inoculum
Inoculum concentration: 25.0 mg/L
Temperature 19.7 – 21.9 °C
Duration 28 days
The test was performed with a nominal start concentration of 20 mg organic carbon/L of the test item.

Apparatus:
The test vessels were aerated with purified (by activated charcoal), CO2-scrubbed, moistened air. The scrubbing of carbon dioxide was achieved by bubbling the purified air through a flask containing 1.5 M NaOH. To control the absence of CO2, the air was then led through a flask containing a solution of Ba(OH)2 before reaching the test vessels.
Magnetic stirrers were used to prevent deposition of inoculum.
The emitted CO2 was trapped in 0.25 M NaOH. Two scrubbers containing 100 mL each were connected in series to the test vessels. The initial IC value of the 0.25 M NaOH was separately determined in each flask.


Sampling:
From each front scrubber flask, 11 samples were taken in order to determine the emitted CO2 (on day 0, 2, 4, 7, 9, 11, 14, 18, 23*, 24 and 29). The sample volume was 1 mL. The resulting change in the volume of the front flask was considered in the calculation of emitted CO2.
On day 28, 5 mL HCl 2 M was added to each test flask in order to drive off dissolved CO2. On day 29, samples from both scrubber flasks were taken.
*due to error of the carbon analyser on day 23 the measured samples gave wrong results. Therefore, sam-ples were taken on day 24. The results of the samples on day 23 were not used for evaluation.

Reference substance

Reference substance:

aniline

Results and discussion

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

ca. 89

Sampling time:

28 d

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Executive summary:

The test item Olive Oil Decyl Esters was tested using a concentration of nominally 20 mg organic carbon/LOlive Oil Decyl Esters in test medium following OECD 301B and EU-Method C.4-C.

The following data were determined for the test item Olive Oil Decyl Esters:

10-day-window:                                                                                                                 day 2 – 12
degradation at the end of 10-day-window                                                                             72 %
degradation at the end of the test                                                                                            89 %
pass level following guideline:       60 % at the end of 10-day-window for pure substances

                                                                respective 60 % at the end of the test for mixtures

 

Therefore, when applying the 10-day-window, the test itemOlive Oil Decyl Esters is readily biodegradable following OECD 301B and EU C.4-C respectively. Because the test item is a mixture the 10-day-window does not have to be taken into account.

As degradation surpassed 60% in the course of the test,Olive Oil Decyl Estersis considered as readily biodegradable.