Fatty acids, C16-18 and C18-unsatd., reaction products with glycidyl neodecanoate and 7-oxabicyclo[4.1.0]hept-3-ylmethyl 7-oxabicyclo[4.1.0]heptane-3-carboxylate

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

Study period:

18 April 2016 to 22 April 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

The test substance is listed as ZEF 6099/100. The test substance, a brown liquid, is the reaction product of C16-C18 and C18 unsaturated fatty acids, with (3,4-epoxycyclohexyl) methyl 3,4-epoxycyclohexylcarboxylate and neodecanoic fatty acid, oxiranylmethylester. The test substance was obtained from the sponsor and was stored at room temperature (15.2 – 20.9°C) in a closed vessel dark and dry.

Analytical monitoring:

yes

Vehicle:

no

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

The culture test species of Desmodosesmus subspicatus was obtained in January 2016 by MBM Sciencebridge GmbH (Institut für Pflanzenphysiologie of Universität Göttingen). The algae are kept as stock culture on solid agar at 2 to 8 °C. From the stock culture, a permanent culture was prepared. From an aliquot of the permanent culture, the pre-culture was prepared.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

No information provided.

Test temperature:

The temperature of the test medium was 22.5°C to 23.4 °C and complied with the requirements of the protocol (21 to 24°C, constant within 2°C).

pH:

The pH during the test measured between 7.5 and 8.3 and complied with the requirements of the protocol (not varying by more than 1.5 unit).

Dissolved oxygen:

No information provided.

Salinity:

No information provided.

Conductivity:

No information provided.

Nominal and measured concentrations:

The experimental test was performed using 5 nominal concentrations ranging from 1 to 100 mg/L ZEF 6099/100; the test solution was prepared using the water accommodated fraction. At the beginning and end of the test, the content of the test item in the test solutions was estimated using DOC-determination. Because of the low solubility in the test medium, no calculation from carbon content of the test item (72.42%) and DOC measurements was possible. The measured DOC concentrations in the treatments were in a similar low range as the blank control. Therefore, the determination of the biological results was based on the nominal concentration. Significant inhibition of algal growth was observed only in the highest concentrated treatment of 100 mg/L ZEF 6099/100.

Details on test conditions:

The cell concentrations of each replicate was determine by measuring the cell numbers every 24 hours with an electronic particle counter. Growth rate µ and the biomass yield were determined from the cell number at the respective observation times.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate K2Cr2O7 (CAS No. 7778-50-9) was used as a positive control in the reference study.

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

48 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

27 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

50 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Results with reference substance (positive control):

The72h-EC50s of potassium dichromate were determined to have fits with a sufficient statistical correspondence of the data with the dose-response equation. The values were within the range of the laboratory (growth rate 0.73 to 1.10 mg/L, yield 0.21 to 0.66 mg/L).

Validity criteria fulfilled:

yes

Conclusions:

The test substance did cause a reduction of growth in a series of algal cultures (test units) exposed to the test item for 72 h. The 72 h NOEC was 32 mg/L and the LOEC was 100 mg/L for growth rate based on nominal concentrations. The 72 h EC10 for growth rate was 48 mg/L and the EC50 was >100 mg/L based on nominal concentrations.

Description of key information

The key study was a static algal growth inhibition test on the effects of ZEF 6099/100 on the freshwater alga, Desmodesmus subspicatus. The 72-h growth rate NOEC was 32 mg/L (based on the water-accommodated fraction); the 72-h growth rate LOEC was 100 mg/L (based on the water-accommodated fraction); the 72-h EC10 was 48 mg/L (based on the water-accommodated fraction); and the 72-h EC50 growth rate was >100 mg/L (based on the water-accommodated fraction).

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

48 mg/L