Reaction mass of 2-O-α-L-Rhamnopyranosyl-α-L-rhamnopyranosyl-β-hydroxydecanoyl-β-hydroxydecanoic acid and α-L-Rhamnopyranosyl-β-hydroxydecanoyl-β-hydroxydecanoic acid

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

no

Remarks:

, but the study was conducted in accordance with ISO/IEC 17025.

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of 2-O-α-L-Rhamnopyranosyl-α-L-rhamnopyranosyl-β-hydroxydecanoyl-β-hydroxydecanoic acid and α-L-Rhamnopyranosyl-β-hydroxydecanoyl-β-hydroxydecanoic acid

EC Number:

604-610-3

Cas Number:

147858-26-2

IUPAC Name:

Reaction mass of 2-O-α-L-Rhamnopyranosyl-α-L-rhamnopyranosyl-β-hydroxydecanoyl-β-hydroxydecanoic acid and α-L-Rhamnopyranosyl-β-hydroxydecanoyl-β-hydroxydecanoic acid

Test material form:

liquid

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): Non-adapted activated sludge from the aeration tank of the ARA Werdhoelzli (Zuerich, Switzerland), a municipal biological waste water treatment plant.
- Concentration of sludge: 30 mg/l dry matter in the final mixture.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

1 002 mg/L

Based on:

test mat.

Remarks:

70.6 mg COD/L

Initial test substance concentration 2

Initial conc.:

30.1 mg/L

Based on:

test mat.

Remarks:

DOC (theoretical value calculated based on the carbon content and the test concentration)

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Aerobic mineral salts medium prepared with ultrapure water (conductivity: <1.5 μS/cm; DOC: <0.5 mg/l)
- Additional substrate: None, test or reference item as sole organic carbon sources.
- Solubilising agent (type and concentration if used): None.
- Test temperature: 22 ± 1 °C
- pH: Before the test start, the pH value was checked and if necessary adjusted to 7.2 (±0.2) with NaOH or HCl. At the end of the test, the pH was measured in all flasks.

TEST SYSTEM
- Culturing apparatus: 510 ml glass bottles (tightly closed with manometric BOD measuring devices) containing a total volume of test solution of 200 ml. The bottles were equipped with stirring rods and butyl rubber quivers which contain two pellets of sodium hydroxide each to absorb the produced CO2 from the headspace.
- Number of culture flasks/concentration: 2
- Measuring equipment: The respirometric activity was measured as pressure change. Because the formed CO2 is adsorbed, O2 consumption leads to a pressure decrease, which is recorded by a manometric BOD measuring device (OxiTop®-C head; WTW Wissenschaftlich-Technische Werkstätten GmbH & Co.
KG, DE-82362 Weilheim). Dissolved organic carbon (DOC) was determined with a Shimadzu TOC-Analyzer TOC-L CSH (Shimadzu Schweiz GmbH, Römerstr. 3, CH-4153 Reinach) using the non-purgeable organic carbon (NPOC) mode.

CONTROL AND BLANK SYSTEM
- Inoculum blank: The procedure control sodium benzoate reached 88% biodegradation after 14 days, thus confirming suitability of inoculum and test conditions
- Abiotic sterile control: Not conducted.
- Toxicity control: Not conducted.


STATISTICAL METHODS: No statistical analysis was performed.

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

Preliminary study:

-

Test performance:

All of the following validity criteria were met:
• The difference of extremes of replicate values of the at the end of the 10-d window or at the end of the test, as appropriate, must be less than 20%
• The percentage degradation of the reference item must reach the pass level of 60% by day 14
• The O2 uptake in the blank control should normally be 20-30 mg O2/l and should not be greater than 60 mg O2/l in 28 days.
• The pH value should be in the range of 6-8.5.

At the end of the test the pH value of the blank control was 7.3 and the procedure control was 7.5.
The pH values of both test units were 7.4. All pH values were therefore in the required range at the end of the test.
The temperature was in the acceptable range during the whole incubation period.

% Degradation

% Degradation 1

Parameter:

% degradation (O2 consumption)

Value:

80.4

Sampling time:

10 d

Remarks on result:

other: mean of two replicates

% Degradation 2

Key result

Parameter:

% degradation (O2 consumption)

Value:

96

Sampling time:

28 d

Remarks on result:

other: mean of two replicates

Details on results:

The biodegradability of the test item based on O2 consumption was calculated to be 96% after 28 days as compared to the chemical oxygen demand (COD).
Biodegradation of the test item started after a lag-phase of about 1 day.
The biodegradation reached about 85% at the end of the 10-d window.
The procedure control sodium benzoate reached 88% biodegradation after 14 days, thus confirming suitability of inoculum and test conditions.
The respective DOC concentrations at the beginning and at the end of the test after 28 days were (in mg/l):
- 30.1 (theoretical value calculated based on the carbon content and the test concentration) and 1.78 for the test units (mean of two replicates)
- <0.5 and 1.05 for the blank control (mean of two replicates)
- 35.21 (theoretical value calculated based on the carbon content and the test concentration) and 1.47 for the procedure control (mean of two replicates)

The calculated total elimination based on DOC measurements reached 98% for the test item and 100% for sodium benzoate, respectively. The data confirm the high biodegradation since the total elimination based on DOC was only slightly higher as compared to the biodegradation based on BOD.
The test item reached the pass level of 60% for ready biodegradability in the Manometric Respirometry Test within the 10-d window and, therefore, can be termed as readily biodegradable.

BOD5 / COD results

Results with reference substance:

Degradation after 3 days > 60% (validity criterion fulfilled)
94.3 % degradation after 28 days

Any other information on results incl. tables

- Evaluation of test results (calculations): see 'Attached background material'

- Data of individual O2 consumption (for test item and procedure control): see 'Attached background material'

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

- biodegradability based on O2 consumption: 96% after 28 days;
- the pass level of 60% for ready biodegradability was reached within the 10-d window: the test item can be termed as readily biodegradable.

Executive summary:

The biodegradability of the test item 'Decanoic acid, 3-[[6-deoxy-2-O-(6-deoxy-α-L-mannopyranosyl)-α-L-mannopyranosyl]oxy]-, 1-(carboxymethyl)octyl ester, mixt. with 1-(carboxymethyl)octyl 3-[(6-deoxy-α-L-mannopyranosyl)oxy]decanoate' exposed to microorganisms derived from activated sludge of a municipal sewage treatment plant was investigated under aerobic static exposure conditions, following the test guideline OECD 301 F.

The biodegradability of the test material based on O2 consumption was calculated to be 96% after 28 days as compared to the chemical oxygen demand (COD).

Biodegradation of the test item started after a lag-phase of about 1 day.

The biodegradation reached about 85% at the end of the 10-d window.

The procedure control sodium benzoate reached 88% biodegradation after 14 days, thus confirming suitability of inoculum and test conditions.

The calculated total elimination based on DOC measurements reached 98% for the test item and 100% for sodium benzoate, respectively. The data confirm the high biodegradation since the total elimination based on DOC was only slightly higher as compared to the biodegradation based on BOD.

The test material reached the pass level of 60% for ready biodegradability in the Manometric Respirometry Test within the 10-d window and, therefore, can be termed as readily biodegradable.