1H-Imidazolium, 3-ethyl-1-methyl-, 1,1,1-trifluoromethanesulfonate (1:1)

Toxicity to aquatic algae and cyanobacteria

Administrative data

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:

other: GLP Guidline Study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1-ethyl-3-methyl-1H-imidazol-3-ium trifluoromethanesulfonate

EC Number:

680-002-1

Cas Number:

145022-44-2

Molecular formula:

C6 H11 N2. C F3 O3 S

IUPAC Name:

1-ethyl-3-methyl-1H-imidazol-3-ium trifluoromethanesulfonate

Details on test material:

Identification: EMIM Triflat
Chemical name: 1H-Imidazolium, 3-ethyl-1-methyl-, 1,1,1-trifluoromethanesulfonate (1:1)
Physical form: liquid
Appearance: yellowish, clear
Water solubility: miscible
Purity: 98.8% (treated as 100% pure)
Composition: EMIM Triflat Anion: 56.2 g/100 g
EMIM Triflat Kation: 42.6 g/100 g
Density: 1.3895 g/cm3 (20°C), 1.3688 g/cm3 (45°C)

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples at the start of the exosure were taken from an additional replicate without algae. At the end of the exposure, test samples were taken directly from the test replicates.

Test solutions

Vehicle:

no

Details on test solutions:

0.100 - 0.320 - 1.00 - 3.20 - 10.0 - 32.0 - 100mg/l (factor √10)

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

- Common name: Desmodesmus subspicatus Chodat
- Strain: SAG 86.81
- Source (laboratory, culture collection): SAG Pflanzenphysiologisches Institut der Universitaet Goettingen, Nikolausberger Weg 18, D-37073 Goettingen, Germany
- Age of inoculum (at test initiation): 3 days
- Method of cultivation: Fresh stocks were prepared from Z-Agar. Light intensity amounted 35 - 70 µE x m-2 x s-1 for 24 h per day.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Hardness:

The test medium had a nominal hardness of 0.24 mmol CaMg/L

Test temperature:

Mean: 21.8 °C, Min: 21.5 °C, Max: 22.0 °C

pH:

Nominal test item concentration pH-value
[mg/L] Start; 0 h End; 72 h
Saturated solution (100 mg/L) 7.89 7.87
Control 8.09 8.25

Dissolved oxygen:

Not measured

Salinity:

Not measured, freshwater

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL Erlenmeyer flasks
- Type (delete if not applicable): closed with cotton wool plugs
- Material, size, headspace, fill volume: sterile 250 mL Erlenmeyer flasks, test volume 100 mL
- Agitation: Test containers were placed on a rotary shaker and oscillated at appr. 70 rpm
- Type of flow-through (e.g. peristaltic or proportional diluter): None
- Renewal rate of test solution (frequency/flow rate): One application at test start
- Initial cells density: 4332 cells/mL
- Control end cells density: Mean 589501 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- No. of vessels per vehicle control (replicates): None


GROWTH MEDIUM
- Standard medium used: yes



TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Dilution water, composition acc. to the guideline
- Hardness: 0.24 mmol Ca+Mg/L
- pH-value: 8.1 +/- 0.2
- Culture medium: Dilution water (according to the guidline OECD 201 medium)


OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: no
- Photoperiod: 24 h
- Light intensity and quality: 60 - 120 µE x m-2 x s-1



EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter] Fluorimeter, via Chlorophyll-a fluorescence (excitation at 436 nm, emission at 685 nm), cell concentrations were related to all cell density values acc. to a calibration curve.



TEST CONCENTRATIONS
- Spacing factor for test concentrations: √10
- Range finding study:
Results of the Range Finding Test (0-72 h)

Nominal test item concentration [mg/L] Inhibition of growth rate [%] Inhibition of yield [%]
100 77 99
10.0 9 39
1.0 5 23
0.1 0 2

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

52.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

18.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Observation of the following abnormalities (for algal test) were performed:
- Unusual cell shape: yes
- Colour differences: yes
- Flocculation: yes
- Adherence to test vessels: yes
- Aggregation of algal cells: yes
Microscopic evalutation of the cells at the start and end of the incubation period revealed no morphological abnormalities.

- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No
- Effect concentrations exceeding solubility of substance in test medium: No

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- EC50:
Rate-related inhibition: 0.631 (CI 0.583 - 0.687) mg/L
Yield Inhibition: 0.256 (CI 0.247 - 0.265) mg/L

Reported statistics and error estimates:

EC10 and EC50-values of the growth rate after 72 hours were calculated by sigmoidal dose response regression. The calculation of the confidence intervals of EC10 and EC50-values were carried out from the best fit values, the standard error and the t-distribution with the software GraphPad Prism.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes