1,2-dimethyl-3-propyl imidazolium bis((trifluoromethyl)sulfonyl)amide

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

Study period:

06 JUN 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted 23 Mar. 2006

Deviations:

yes

Remarks:

the temperature in the experiment was higher than stated in the guideline. Because normal growth was observed, this can be stated as uncritical. The deviation was assessed and signed by the study director on 10 June 2016.

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: Regulation EC No2016/266 amending Regulation No 440/2008, Annex IV, Method C.3.: "FRESHWATER ALGAE AND CYANOBACTERIA, GROWTH INHIBITION TEST",

Version / remarks:

adopted 07 Dec. 2015

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: OECD guidance document No. 23, GUIDANCE DOCUMENT ON AQUATIC TOXICITY TESTING OF DIFFICULT SUBSTANCES AND MIXTURES

Version / remarks:

adopted 14 Dec. 2000

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesamt für Umwelt, Wasserwirtschaft und Gewerbeaufsicht, Mainz, Germany

Test material

Test material information

Constituent 1

Reference substance name:

1,2-dimethyl-3-propyl imidazolium bis((trifluoromethyl)sulfonyl)amide

EC Number:

805-807-9

Cas Number:

169051-76-7

Molecular formula:

C10H15F6N3O4S2

IUPAC Name:

1,2-dimethyl-3-propyl imidazolium bis((trifluoromethyl)sulfonyl)amide

Test material form:

liquid

Details on test material:

Appearance : colorless oil
Composition: a base stock containing (C, 28.64; H, 3.61; F, 27.18; N, 10.02; O, 15.26; S, 15.29)
Molecular formula : C10H15F6N3O4S2
Molecular Weight : 419.12 g/mol
Purity >99% (purity determined by MNR)
Homogeneity : homogeneous

Specific details on test material used for the study:

Designation in Test facility : 16040601G
Date of receipt : 06 April 2016
condition of receipt : Room temperaure, in proper conditions
batch N° L 16-0157
Homogeneity : homogeneous
Volatility : unknown
Stability H2O: 96h; EtOH: 96h; acetone: 96h; CH3CN: 96h; DMSO: unknown
Solubility H2O:7.76 ± 0.16 g/L at 20 ± 0.5 °C (determined in LAUS study N°15121001G910) ; EtOH: > 1 g/L; acetone: > 1 g/L; CH3CN: < 0.1 g/L; DMSO: > 1 g/L
Production date 26. Feb. 2016
Expiry date 26. Feb. 2030
storage : room temperature (20 ± 0.5 °C)

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

The study was performed using 5 concentrations (4,6 ; 10; 22; 46 and 100 mg/l)
For each treatment, 200 mL of the respective test item solution was mixed with the necessary amount of algal pre-culture (1.26 mL).
For the blank control, 350 mL nutrient medium was used instead of test item solution and mixed with the necessary amount of algal pre-culture (2.20 mL).

Test solutions

Vehicle:

no

Details on test solutions:

A stock solution containing 100.3 mg/L in algal medium (demineralised water enriched with minerals but without algae) was prepared. The lower treatments were prepared by dilution of this stock solution with nutrient medium.

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

SAG Strain number : 86.81
The culture of Desmodesmus 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 - 8 °C. From the stock culture, a permanent culture was prepared.
Three days before the start of the test, an aliquot of the permanent culture was brought into nutrient medium and incubated under continuous lighting for 72 hours. The resulting culture grew exponentially. Before usage, this pre-culture was checked for the absence of cell aggregates and the cell number of culture was determined.

Study design

Test type:

not specified

Water media type:

other: OECD medium

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

20.9 - 25.2 °C

pH:

7.6 (at 0 h)
7.4 (at 72 h)

Nominal and measured concentrations:

Nominal concentration: 4.6 /10 / 22/ 46/ 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel (material, size): glass flasks total volume 65 ml
- Type: open (covered with perforated plastic foil)
- fill volume: 45ml
- Aeration: shaken on an orbital shaker
- Initial cells density: 4220 cells/mL
- cell number was determined every 24 hours, with an electronic particle counter
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
GROWTH MEDIUM
- Standard medium used: yes (OECD medium)
TEST MEDIUM / WATER PARAMETERS
- Culture medium different from test medium: no
OTHER TEST CONDITIONS
- Sterile test conditions: yes (reported for medium preparation)
- Photoperiod: continuous illumination
- Light intensity and quality: 5300 Lux
- pH value was measured at the start and at the end of the test
EFFECT PARAMETERS MEASURED
- At the end of the test, the treatments were examined microscopically in order to assess the appearance of the algae and detect abnormalities (e.g. caused by the exposure to the test item).
TEST CONCENTRATIONS
- Test concentrations: at the start and at the end of the test, the content of the test item in the test solutions was determined using DOC measurement.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

46 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

46 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Yield

Effect concentrations 3

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

Effect concentrations 4

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Yield

Effect concentrations 5

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

56 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 6

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

33 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

other: Yield

Effect concentrations 7

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 8

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

63 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

other: Yield

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): less cells at 100mg/L
- Unusual cell shape: not specified
- Any stimulation of growth found in any treatment: yes

Results with reference substance (positive control):

Results with reference substance valid ? yes
The 72h-EC50s of potassium dichromate were determined in a separate reference test performed under GLP conditions in March 2016.
72h ErC50: 0.91 mg/L (95% CI 0.76 - 0.85 mg/L)
72h EyC50: 0.66 mg/L (95% CI 0.35 - 0.38 mg/L)
These values lay within the range of the laboratory (growth rate 0.73 - 1.10 mg/L, yield 0.21 - 0.66 mg/L)

Reported statistics and error estimates:

Equality of variance was tested. As equality of variance was given, the t-test was used. With the t-test, it was checked whether the differences are significant. Significance is given if the calculated t-value is bigger than the limit of significance (level of significance 95%). For the endpoints Growth Rate and Yield, the differences between the nominal loading 100 mg/L and the control are considered as significant.

Any other information on results incl. tables

The means and standard deviations of the cell numbres of the control and the treatments are presented in the following table.

Table 1 : Cell Numbers/ml

Nominal Concentration  in mg/L	Parameter	Cell Number/mL
		0 h	24 h	48 h	72 h
Blank control	Mean	4220	24217	86110	302270
Blank control	SD	0	1361	10261	57883
4.6	Mean	4220	28180	149693	627813
4.6	SD	0	4984	15668	64752
10	Mean	4220	24180	126620	557727
10	SD	0	1159	15192	57392
22	Mean	4220	25980	145240	636173
22	SD	0	433	3660	26718
46	Mean	4220	20987	80027	304833
46	SD	0	3526	8841	84572
100	Mean	4220	18767	47660	116587
100	SD	0	1968	8380	29279

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

All validity criteria were met.
No observations were made which might cause doubts concerning the validity of the study outcome.
The result of the test can be considered valid.

Executive summary:

One valid experiment was performed.

The study was performed using 5 concentrations ranging from 4.6 to 100 mg/L.Incubation time (test system Desmodesmus subspicatus) was 72 hours. The cell concentration of each replicate was determined by measuring the cell numbers every 24 hours with an electronic particle counter. Growth rate µ and the yield were determined from the cell number at the respective observation times.

Significant inhibition of algal growth was observed in the highest concentration of 100 mg/L only.

At the start and at the end of the test, the content of the test item in the test solutions was determined using DOC measurement. The calculated test item concentrations based on DOC measurement lay between 95% and 104% of the nominal concentration at the beginning of the test and between 98% and 106% of the nominal concentration at the end of the test. Therefore, the determination of the results was based on the nominal concentrations.

The 72h-EC50s of potassium dichromate were determined in a separate reference test. the values lay within the range of the laboratory (growth rate 0.73 - 1.10 mg/L, yield 0.21 - 0.66 mg/L).

The following results were determined for 1-propyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl) imide :

Endpoint	NOEC	LOEC	EC10	EC50
Growth Rate	46 mg/L	100 mg/L	56 mg/L	> 100 mg/L
Yield	46 mg/L	100 mg/L	33 mg/L	63 mg/L