2-(2-heptadec-8-enyl-2-imidazolin-1-yl)ethanol

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:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Specific details on test material used for the study:

- Physical state: yellow to brown, clear liquid
- Analytical purity: 96.6 %
- Batch No.: 05774HP8
- Storage condition of test material: The test substance was stored at ambient temperature

Analytical monitoring:

yes

Details on sampling:

- Sampling was performed at the start of the exposure (0 h) from the inoculated replicate 7 of each concentration and the control.
- At the end of the exposure (72 h) samples of the inoculated replicates 1-3 of the test concentrations and of the inoculated replicates 1- 6 of the control group were taken.
- The replicates were combined before sampling.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The stock test solution (1 mg/L) was prepared by directly adding 2.04 mg of test substance to 2 L of test medium and stirring for approximately 1 day at 20 ± 2 °C. Before the dilution was performed, the stock solution was visually checked for complete dissolution of the test substance. The solution was further inspected for the presence of any undissolved test substance by observing the scatting of a laser light through the test solution (i.e. Tyndall effect). The stock solution was visibly colorless and clear and no scattering of laser light was observable. The test vessels were saturated with test solution for approx 1 day before the start of exposure.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: green alga
- Strain: SAG 86.81
- Source: Collection of algal cultures in University of Göttingen, Germany
- Age of inoculum (at test initiation): 4 days

CULTURE CODITIONS
An inoculum culture in exponential growth phase was prepared with an aliquot of the stock algal culture added to sterile test media to provide an initial cell density of 0.5E+04 cells/ml. The inoculum culture is incubated under test conditions for 4 days prior to test initiation. The increase in biomass is verified to ensure that growth is within the normal range and algal cells are examined microscopically for normal morphology prior to use for test inoculation.
- Inoculum culture cell density (4 days growth): 128E+04 cells/mL (256 fold increase)
- Inoculum culture morphology: normal and healthy

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

23.1 - 23.5 °C

pH:

7.9 - 8.4

Nominal and measured concentrations:

- Nominal test concentrations: control, 0.0046, 0.010, 0.022, 0.046, 0.10 mg/L (based on range-finding study)
- Mean measured concentrations: control, 0.0044, 0.0110, 0.0169, 0.0338, 0.0871 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, nominal volume, fill volume: Erlenmeyer flasks plugged with gas permeable silicone sponge caps, 250 mg/L, 100 mg/L
- Initial cells density: 0.5E+04 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: The test medium was prepared according to OECD Guideline for Testing of Chemicals, No. 201 Algal growth inhibition test
- Culture medium different from test medium: no
- Intervals of water quality measurement: pH in one uninoculated replicate and one inoculated replicate at study initiation and in all replicates at study end. Temperature was continuously measured during the whole test period in the climate chamber in a flask with deionized water

OTHER TEST CONDITIONS
- Photoperiod: permanent illumination
- Light intensity and quality: artificial light, type universal white (OSRAM L 25), average 5088 lux (within ± 15% variability) at a wave length of 400 - 700 nm

EFFECT PARAMETERS MEASURED:
- Determination of cell concentrations: two counts in a Neubauer haemocytometer
- Chlorophyll measurement: in vivo chlorophyll-a fluorescence (pulsed excitation with light flashes having a wavelength of 432 nm) after 0, 24, 48, 72 h
- Other: The inoculum culture was observed microscopically at the start of the test to verify normal and healthy cells. At test termination, a pooled sample from each test concentration was examined and any abnormal appearance of the algae noted.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: geometric series, ≤3.2
- Range finding study: yes
- Results used to determine the conditions for the definitive study (72 h): EfC50 = 0.03 mg/L (nominal) ; ErC50 = 0.03 mg/L (nominal)

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.03 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.014 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.011 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC90

Effect conc.:

> 0.087 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

0.017 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.012 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: yield

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.017 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: yield

Duration:

72 h

Dose descriptor:

EC90

Effect conc.:

0.032 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: yield

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.011 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: yield

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

0.017 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: yield

Description of key information

The substance is acutely very toxic to aquatic algae.

ErC50 = 0.03 mg/L (Desmodesmus subspicatus)

ErC10 = 0.0143 mg/L (Desmodesmus subspicatus)

Additional information

The toxicity towards freshwater algae was determined in a study according to OECD TG 201 and in compliance with GLP criteria (BASF, 2010). In this study, exponentially growing freshwater algae (Desmodesmus subspicatus) were exposed to nominal test substance concentrations of 0 (control), 0.0046, 0.010, 0.022, 0.046 and 0.10 mg/L for 72 hours under static conditions. The selected test concentrations were based on a range-finding study. Nominal concentrations were analytically verified and determined to be 0 (control), 0.0044, 0.0110, 0.0169, 0.0338 and 0.0871 mg/L mg/L (mean measured concentrations). At the start of the test and after 24, 48 and 72 hours exposure duration, the algae were counted and fluorescence (chlorophyll) was measured. Furthermore, the inoculum culture was observed microscopically for abnormal appearances at the test start and a pooled sample from each test concentration was observed at test termination. The 72-h EC50 values for growth rate and yield are determined at 0.03 mg/L and 0.0169 mg/L, respectively. The 72-h EC10 values are 0.0143 for growth rate and 0.0122 mg/L for yield, respectively.