Fatty acids, tall-oil, reaction products with linseed oil, maleic anhydride and methanol

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:

17 August 2015 to 25 September 2015

Reliability:

1 (reliable without restriction)

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 ZWA 5496/100. The test substance, a brown liquid, is the reaction product of maleic anhydride, disproportioned tall oil fatty acid, linseed oil and methanol. The test substance was obtained from Allnex Belgium and was stored at room temperature (20 ± 5°C) and kept away from light

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 February 2014 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 infomration provided.

Test temperature:

The temperature of the test medium was 20.8°C to 23.7 °C (first experiment) and 20.8°C to 23.0 °C (second experiment) and complied with the requirements of the protocol (21 to 24°C, constant within 2°C).

pH:

The pH during the test measured between 7.4 and 8.6 (first experiment) and between 7.5 and 8.7 (second experiment) 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:

Two valid experiments were performed; the test solution was prepared using the water-accomodated fraction. The first experimental test was performed using 5 nominal concentrations ranging from 10 to 100 mg/L ZWA 5496/100. Because significant inhibition of algal growth was observed in the lowest concentration, a second experiment was performed using 5 nominal concentrations ranging from 1 to 100 mg/L ZWA 5496/100.

Details on test conditions:

The cell concentrations of each replicate was determine by measuring the absorption of the solutions at 440 nm every 24 hours with a spectral photometer. The cell density of the cultures was calculated based on the correlation curve between the absorption and the cell density of the cultures determined with a cell counter. Growth rate and biomass yield were determined from the cel 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.:

10 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.:

32 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.:

11 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.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

3.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

3.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Results with reference substance (positive control):

The 72h-EC50s of potassium dichromate were determined. The data exhibited sufficient statistical correspondence with the dose-response equation. The 72-h ErC%0 was reported as 1.1 mg/L; the 72-h EyC50) was reported as 0.39 mg/L.

Validity criteria fulfilled:

yes

Remarks:

pH range 7.4 to 8.6 (first test) and range 7.5 to 8.7 (second test) (protocol limits not varying by more than 1.5 unit); 20.8°C to 23.7 °C (first test) and 20.8°C to 23.0 °C (second test) (protocol requires 21 to 24°C, constant within 2°C).

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 10 mg/L and the LOEC was 32 mg/L for growth rate based on nominal concentrations. The 72 h ErC10 for growth rate was 11 mg/L and the ErC50 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 the substance on the freshwater alga, Desmodesmus subspicatus. The 72-h growth rate NOEC was 10 mg/L (based on the water-accommodated fraction); the 72-h growth rate LOEC was 32 mg/L (based on the water-accommodated fraction); the 72-h EC10 was 11 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:

11 mg/L