Honeysurf HF

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:

7th March - 4th April 2022

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2022

Report date:

2022

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Sophorolipids: fermentation products of glucose and fatty acids, C18 (unsaturated), glycerol esters with yeast Starmerella bombicola, partially hydrolysed, sodium salts

IUPAC Name:

Sophorolipids: fermentation products of glucose and fatty acids, C18 (unsaturated), glycerol esters with yeast Starmerella bombicola, partially hydrolysed, sodium salts

Specific details on test material used for the study:

Batch: H21145-03
Purity: As supplied
Expiry: May 2023

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

natural water: freshwater

Details on inoculum:

Surface water was collected from Malmesbury Pond, Sandymoor, Runcorn on 7th MArch 2022 and assigned a batch number of SE22002. After collection the inoculum was coarse filtered and aerated at 22oC =/-2oC prior to use as the test inoculum. It was added to test media at an inoculum dosage of 2.5 mL per litre of media.

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

2.75 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

2 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Duplicate (completely filled and sealed glass BOD bottles, 272 mL volume) bottles for each of the sample days were prepared for each of the test and reference materials. Three replicates were prepared for the controls. Bottles were incubated at 20.5 - 22.9 oC in the dark.

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (O2 consumption)

Value:

66.2

Sampling time:

28 d

Remarks on result:

other: 2.75 mg/L

% Degradation 2

Parameter:

% degradation (O2 consumption)

Value:

53.2

Sampling time:

28 d

Remarks on result:

other: 2.0 mg/L

% Degradation 3

Key result

Parameter:

% degradation (O2 consumption)

Value:

67.5

Sampling time:

14 d

Remarks on result:

other: 2.75 mg/L

% Degradation 4

Key result

Parameter:

% degradation (O2 consumption)

Value:

64.3

Sampling time:

14 d

Remarks on result:

other: 2.0 mg/L

% Degradation 5

Parameter:

% degradation (O2 consumption)

Value:

38.9

Sampling time:

3 d

Remarks on result:

other: 2.75 mg/L

% Degradation 6

Parameter:

% degradation (O2 consumption)

Value:

43.1

Sampling time:

3 d

Remarks on result:

other: 2.0 mg/L

BOD5 / COD results

Results with reference substance:

Sodium Benzoate at 2.5 mg/L:
80.5% degradation at Day 3
86.2% degradation at Day 14
69.0% degradation at Day 28

Any other information on results incl. tables

The start of the 10 day window in this study is between 1 and 3 days. Therefore, the 10 and 14 day windows can only end on Day 14 according to how the test has been set up.

We therefore have 64.3% degradation at 2.0 mg/L and 67.5% degradation at 2.75 mg/L. This does show that the substance was readily biodegradable as 60% ThOD was reached within the 10/14 day window.

28 results for the 2.0 mg/L concentration show a result which is lower than the previous time points. As this test is one bottle per timepoint, this is believed to be an anomomlous result.

 

 

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable