Sophorolipids: fermentation products of glucose and rapeseed-oil fatty acids methyl esters with yeast Candida Bombicola

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

no

Remarks:

The testing lab was not GLP in 2009 but study of good quality (klimisch score 2) so can be used for registration purpose

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

23°C +/- 2

pH:

7

Nominal and measured concentrations:

Test 1: 61.8, 121, 238.1, 475.6 and 1002.4 mg MS/L along with a control; Test 2: 19.7, 39.4, 78.8, 200.4 and 393.8 mg MS/L along with a control.

The test concentrations and effect results are expressed in mg of dry matter in the product per litre (mg MS/L, where MS = matière seche).

Reference substance (positive control):

yes

Remarks:

K2Cr2O7

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

87 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks on result:

other: Test 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

65 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks on result:

other: Test 2

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

76 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks on result:

other: Average of two tests.

Details on results:

CEr50-72h dry material : 76 mg/l
CEr50-72h raw material : 127 mg/l

Results with reference substance (positive control):

CEr50-72h : 0.98mg/l

Validity criteria fulfilled:

yes

Conclusions:

CEr50-72h dry material : 76 mg/l (average of two tests)

Description of key information

Commercial samples of the registered substances are typically produced as aqueous solutions. An algae inhibition study was performed on a commercial quality of Sophorolipids (Lot 01/09), which had been determined to contain 60.6% dry matter. The % dry matter is equivalent to the Sophorolipid content of the test item.

Two tests were performed in the study, each using different concentration ranges, 61.8-1002.4 and 19.7-393.8 mg “dry matter” /L. The 72h ErC50 determined from both tests was similar (87 and 65mg/L based on dry matter). The average value of 76 mg “dry matter”/L has been chosen as the key value.  A NOEC or EC10 was not determined.

Key value for chemical safety assessment

EC50 for freshwater algae:

76 mg/L

Additional information

The effect of the registered substance (test item Sophorolipids, purity 60.6% dry matter) on the Growth of Freshwater Alga (Scenedesmus subspicatus) was followed over a period of 72 hours. The study was performed according to the European Standard ISO 8692 and OECD Guideline 201. Two tests were performed. The test concentrations and effect results are expressed in mg of dry matter in the product per litre (mg MS/L, where MS = matière seche).

The first test was performed at test concentrations of 61.8, 121, 238.1, 475.6 and 1002.4 mg MS/L along with a control.  At the end of 72 hour observation period, 40.0%, 55.8%, 92.9%, 100% and 100% growth inhibition was observed in the test concentrations of 61.8, 121, 238.1, 475.6 and 1002.4 mg MS/L respectively. The 72h EC₅₀ based on growth rate was calculated to be 87 mg MS/L.

The second test was performed at test concentrations of 19.7, 39.4, 78.8, 200.4 and 393.8 mg MS/L along with a control. At the end of 72 hour observation period, 12.1%, 19.0%, 59.2%, 95.9% and 100% growth inhibition was observed in the test concentrations of 19.7, 39.4, 78.8, 200.4 and 393.8 mg MS/L respectively. The 72h EC₅₀ based on growth rate was calculated to be 65 mg MS/L.

The average 72 ErC50 from the two tests is 76mg MS/L.

A NOEC or EC10 was not determined.