Fatty acids, tall-oil, reaction products with pentaethylenehexamine

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:

2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD guideline study according to GLP.

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Analytical determinations of the test substance concentrations was based on dissolved organic carbon (DOC). Determinations was conducted when the test substance concentrations were freshly prepared, after 24, 48 and 72 h of the exposure. Each replicate was measured individually.

Vehicle:

no

Details on test solutions:

Since the test substance is a multi-component substance that is only partially soluble, the water accommodated fraction (WAF) approach was used. The test loadings were prepared by adding the respective amount of an acetone stock solution to the individual test vessels. After complete evaporation of the solvent, aerated algal medium was added, moderately stirred for 24 h, followed by filtration (0.45 µm cellulose acetate membrane sterile syringe filter, VWR International). The resulting water soluble fractions (WSF) were used in the test.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

Test organism: Axenic slope culture of Desmodesmus subspicatus 86.81 SAG (Collection of Algal Cultures, Institute of Freshwater Ecology, University of Göttingen, D-37073 Göttingen, Germany)
Culture: 250 ml flask containing 100 ml of sterile OECD medium (Table 1) inoculated with cell material from axenic slope cultures
Illumination: Continuous (2000–3000 lux) from Osram Fluora L18W77 and Osram Daywhite L18W840 (Osram AG, Winterthur, Switzerland)
Temperature: 22 ± 2 °C, thermo-controlled room
Control of sensitivity: The culture is yearly re-purchased. Potassium dichromate is used to control the sensitivity of the culture twice a year.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

22 ± 2°C, thermo-controlled room

pH:

control: 8.0 - 8.7
exposure groups: 8.0

Nominal and measured concentrations:

Based on the results of this range finding test, the definitive test was performed at the following loading rates of Fatty acids, tall-oil, reaction products with pentaethylenehexamine: 0.625, 1.25, 2.50, 5.00 and 10.0 mg/l

Details on test conditions:

Test vessel: 250 ml flasks, all-glass, with 100 ml of test medium, shaken (about 130 rpm)
Test medium: Recommended OECD medium
Preculture: Exponentially growing liquid culture of Desmodesmus subspicatus

Illumination:
Source: continuous from Osram Fluora L 18W77 and Osram Daywhite L 18W840 (Osram AG, Winterthur, Switzerland)
Light intensity (target): the light intensity amounts to about 3000 lux which corresponds to about 40 μE•m-2•s-2 according to the OECD TG no. 201
Homogeneity (target): the light intensity is maintained within ±15% from the average light intensity over the incubation area

Temperature (target): 22 ± 2°C, thermo-controlled room
pH: The pH of the control medium should not increase by more than 1.5 units during the test
Test type: Static exposure conditions over a period of 72 h
Starting cell density: 0.50–0.85 µg/ml with respect to dry weight corresponding to about 2–5•10E3 cells/ml (i.e. OD680 of about 0.005 units)

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.387 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

0.759 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

2.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.406 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

0.619 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1.27 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Details on results:

DOC analyses of the test substance concentrations were conducted at the beginning, after 24 and 48 h, and at the end of the exposure (72 h). Net DOC concentrations (DOC concentrations after subtraction of the blank) at the beginning of the exposure were 2.09, 1.69, 1.67, 1.38 and 2.05 mg C/l. With respect to a TOC content of 75.6%, these concentrations correspond to 2.76, 2.23, 2.20, 1.83 and 2.72 mg/l of the test substance, respectively. The analyses confirmed the low solubility of the test substance. Geometric mean concentrations of the DOC over a period of 0-72 h (GM0-72h) were 0.769, 0829, 0.821, 0.672, and 1.22 mg C/l. These concentrations correspond to 1.02, 1.09, 1.09, 0.889 and 1.61 mg/l of the test substance. All the measured concentrations were close to the limit of quantification (LOQ) of 0.5 mg C/l, which hampers precise measurements. Therefore, the evaluation was based on the loading rates of the test item.

Validity criteria fulfilled:

yes

Description of key information

Acutely toxic to aquatic algae. 

Additional information

The toxicity to aquatic algae was assessed in an OECD 201 guideline study according to GLP. Due to the results of a range finding study the concentrations in the definite test were 0.625, 1.25, 2.5, 5.00 and 10 mg/L. The results are based on the loading rates due to the uvcb character of the test substance. The median effect concentration with respect to growth rate to Desmodesmus subspicatus was calculated to be 2.4 mg/l loading rate. The median effect concentration with respect to yield to Desmodesmus subspicatus was calculated to be 1.27 mg/l loading rate.