bis(trifluoromethylsulfonyl)azanide;1-ethyl-3-methylimidazol-3-ium

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:

Study Plan dated: 19.Sep.2018; Experimental starting Date: 19.Mar.2019; Experimental Completion Date: 26.Mar.2019

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

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:

23. March 2006; Annex 5 corrected: 28. July 2011

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

07. December 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:

06. Jul. 2018

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesamt für Umwelt; Kaiser-Friedrich-Straße 7, 55116 Mainz

Test material

Test material information

Constituent 1

Reference substance name:

1-ethyl-3-methyl-1H-imidazol-3-ium; trifluoro[(trifluoromethanesulfonylazanidyl)sulfonyl]methane

EC Number:

700-235-5

Cas Number:

174899-82-2

Molecular formula:

C8H11F6N3O4S2

IUPAC Name:

1-ethyl-3-methyl-1H-imidazol-3-ium; trifluoro[(trifluoromethanesulfonylazanidyl)sulfonyl]methane

Test material form:

liquid

Details on test material:

clear liquid, colorless

Specific details on test material used for the study:

- Source and lot/batch No.of test material: proionic GmbH; Lot.-No.: 25PI208_12
- Expiration date of the lot/batch: 01.May 2019
- Purity test date: EMIM+: 99.84 wt% HPLC; NTF2-: 99.95 wt% IC


- Storage condition of test material: room temperature (20 +/- 5 °C), keep away from humidity


T

Sampling and analysis

Analytical monitoring:

yes

Remarks:

LC-MS-MS

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Strain: SAG 86.81
- Source (laboratory, culture collection): MBM Sciencebridge GmbH
- Method of cultivation: stock culture on solid agar

Study design

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Test temperature:

22.8 - 24.3 °C

pH:

Nominal Concentration in mg/L 0 h 72 h
Blank control 7.9 7.8
0.1* 7.9 7.8
0.32* 7.9 7.8
1 7.9 7.8
3.2 7.9 7.8
10 7.9 7.8

Details on test conditions:

Date: 19. – 22. March 2019
Treatments tested: 0.1 / 0.32 / 1 / 3.2 / 10 mg/L nominal concentration
The concentrations to be tested are based on non GLP pre-tests
Number of replicates: 6 replicates for the blank control
3 replicates for each treatment
Vessels: glass flasks total volume 65 mL
Duration: 72 hours
Lighting: 5000 lux
Temperature: 22.8 – 24.3°C (see chapter 13 Deviations)
Replicates (Blank control): 45 ±1 mL algal medium and algae
Replicates (Treatments): 45 ±1 mL test solution and algae

Reference substance (positive control):

yes

Remarks:

Potassium dichromate (K2Cr2O7; CAS No. 7778-50-9)

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

13.17 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

3.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

4.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Results with reference substance (positive control):

The results of the last study with the positive control K2Cr2O7 are presented in the follow-ing table. The study was performed under GLP conditions in June 2018.
Table Biological Results of K2Cr2O7
Parameter Value 95% confidence interval
72h ErC50 0.65 mg/L 0.60 mg/L – 0.71 mg/L
72h EyC50 0.28 mg/L 0.21 mg/L – 0.38 mg/L

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Executive summary:

One valid experiment was performed.

The study was performed using 5 concentrations ranging from 0.1 to 10 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[1] were determined from the cell number at the respective observation times.

 

Significant inhibition of algal growth was observed at the following concentrations:

3.2 – 10 mg/L

 

As no inhibition occurred in the three lowest treatments, only the three highest concentrations (1 – 10 mg/L) would be used for evaluation.

At the start and at the end of the test, the content of the test item in the test solutions was determined using LC-MS-MS.

The measured concentrations of the three highest treatments lay between 85 % and 92 % of the nominal concentrations at the beginning of the test and between 92 % and 100 % of the nominal concentrations at the end of the test. Therefore, the biological results were based on the nominal concentrations (cf. Guidance Doc. No. 23 §176).

 

The 72h-EC₅₀values of potassium dichromate (K₂Cr₂O₇, CAS No. 7778-50-9) were determined in a separate reference test. The values lay within the range of the laboratory (growth rate 0.65 - 1.10 mg/L, yield 0.21 – 0.66 mg/L).

The following results for the test item1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imidewere determined:

Table: Results of the test item

Endpoint	NOEC	LOEC	EC10	EC50
Growth Rate	1.00 mg/L	3.20 mg/L	4.70 mg/L	13.17 mg/L
Yield	1.00 mg/L	3.20 mg/L	2.50 mg/L	5.19 mg/L

[1]Yield (according to OECD Guideline 201) is defined as the biomass at the end of the exposure period minus the biomass at the start of the exposure period. Calculation see under 8.2 Growth and growth inhibition are quantified from measurements of the algal biomass as a function of time. Algal biomass is defined as the dry weight per volume, e.g. mg algae/L test solution. However, dry weight is difficult to measure and therefore surrogate parameters are used. Of these surrogates, cell counts are most often used.