lithium bis(fluorosulfonyl)imide

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:

The study was conducted between 21 May 2010 and 22 July 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

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

Version / remarks:

The definitive tests were conducted twice. Since variability of the growth rates in the control group was out of the criteria in the first definitive test, the test was not accepted. Accordingly, the second definitive test was conducted under the same conditions as the first definitive test except changing the rotation position of the test vessels in the incubator. In this report, only the second definitive test is described.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

lithium(1+) bis(fluorosulfonyl)azanide

EC Number:

924-516-9

Cas Number:

171611-11-3

Molecular formula:

(FSO2)2NLi

IUPAC Name:

lithium(1+) bis(fluorosulfonyl)azanide

Specific details on test material used for the study:

Abbreviated name: LiFSI
Lot No.: KSI00ll3
Purity: Solid content; 24.0% aqueous solution (information from the analytical report of Dai-ichi Kogyo Seiyaku Co., Ltd.)
Appearance: Colorless and transparent l iquid
Received date: January 18, 2010
Expiration date: January 18, 2013
Storage conditions: Stored in a refrigerator with a polypropylene container

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

The measurement was conducted at the exposure i nitiation and termination. At the exposure initiation, 10-mL samples were collected from each remainder of the test solutions from each group after preparation. At the exposure termination, 3-mL samples were collected from each triplicate test solution from the mid-depth of the test vessels and the three samples from the same group were mixed to be a 9-mL sample solution. (1.5-mL samples were collected from each six replicate test solution in the control group).

Test solutions

Vehicle:

no

Details on test solutions:

Preparation of the test solutions
An amount of the test substance (624.9 mg; 150 mg as LiFSI [corrected for purity (24.0%)]) was weighed and transferred to a 300-mL volumetric flask and dissolved in the OECD medium and the volume was adjusted to prepare a 500 mg/L stock solution. These stock solutions of 6.25, 12.5, 25.0 50.0 and 1 00 mL were separately transferred to 500-mL flasks and filled to volume with OECD medium to prepare the test solutions of 6.25, 12.5, 25.0, 50.0 and 100 mg/L. Three vessels each containing 100 mL of the test medium were used for each exposure group. Six vessels each containing 100 mL of the OECD medium (without the test substance) were used for the control group.

Test organisms

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

Obtained from: National Institute for Environmental Studies
Acquisition date: July 3, 2008
Strain: NIES-35
Pre-culture conditions: The test organisms used in this study were cultured under the same conditions as those to be used in the study and in log growth phase at the staii of the exposure. After the pre-culture period, the cells were observed
microscopically to confirm that neither modification nor abnormal appearance of the algae was shown.
Culture period; June 4-7, 2010
Temperature; 23.1 °C (in the incubator)
Lighting; 72-76 μE/m2/s under continuous illumination (cool white fluorescent lamp, measured at the level of the solutions in flasks)

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

23±2°C

pH:

7.9-8.1

Nominal and measured concentrations:

A range-finding test (Report No.; NCAS 10-063NG) at nominal concentrations of 0.500, 5.00 and 50.0mg/L (as LiFSI) was conducted and % inhibition of growth rates during 0-72 hours were 0.0, 0.0 and 4.95%
respectively.
On the basis of the above results, the definitive test was conducted at 5 nominal concentrations (common ratio; 2.0 as LiFSI) of 6.25, 12.5, 25.0, 50.0 and 100 mg/L under open system.

Since the measured concentrations of the test substance at the start and end of the exposure were within ±20% of the nominal, the nominal concentrations were regarded as the test concentrations during the exposure period.
The concentrations of the test substance in the test solutions were 104-106% of the nominal at the exposure initiation and 99.6 - 103% of the nominal at the exposure termination. The concentrations of the test substance in the test solutions were stable during the exposure period.

Details on test conditions:

Test conditions
Type of culture: Shaking culture (100 rpm)
Volume of test solutions: 100 mL / vessel
Vessels: 300-mL conical glass vessels with aluminum caps (air-permeable)
Replicates: 3 vessels / exposure group (6 vessels / control group)
Initial cell density: 5000 cells / mL (nominal)
Lighting: 65-100 μE/m2/s under continuous illumination (cool white fluorescent lamp, measured at the level of the solutions in flasks)
Medium: OECD medium

Experimental procedures
The cell density in the pre-culture was 5.25 x 10^5 cells/mL. An amount of the pre-culture (952 μL), which was calculated to provide the nominal cell density of 5000 cells/mL in each test solution, was aseptically introduced to each test vessel containing the test solution with a micropipette. After inoculation, the test vessels were placed in the incubator (nominal temperature of the incubator: 23.0°C) and the incubation started.
The cell density in each test vessels was measured after 24, 48 and 72 hours of the exposure .The test vessels were repositioned daily during the exposure period. At the exposure initiation, pH in the remains of test solution was measured in each test group (each exposure and control group) after preparation. At the exposure termination, pH in one of the replicates was measured in each test group. Temperature and light intensity in the incubator were measured once daily during the exposure period.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

50 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

Growth curve and growth rate
The cell density in the control cultures increased by a factor of 172 within the exposure of 72-hours which was satisfied the test criterion (more than 16-fold). The mean coefficient of variation (CV ) for daily specific growth rates (days 0-1, 1-2, 2-3) in the control cultures was 8.54% which was satisfied the criterion (within 35%). The coefficient of the variation of average specific growth rates during the whole exposure period (0-72 h) in replicate control cultures was 3.62% which was satisfied the criterion (within 7%). Since linearity of the growth curves in the control group was observed, it was confirmed that the cells were in the exponential growth phase during the exposure period.

ErC50, 95% confidence interval and NOECr
The ErC50 (0-72 h) and NOECr were detennined on the basis of the nominal test concentrations. Since the percent inhibition was less than 50% even at the highest concentration tested, the ErC50 (0-72h) was determined to be > 100 mg/L.
Based on the results of the Dunnett test (2-sidid), the NOECr, which is defined as the highest concentration group that caused no significant different (p≥0.05) from the control data, was determined to be 50.0 mg/L.

Microscopic observations of algae
There were no morphological abnormalities in cell shape of the control cultures throughout the exposure period. Morphological abnormality (distmied shape) was observed in the 100 mg/L from 48 hours after the exposure.

Validity of the test
The validity of the test was confirmed because the following criteria were satisfied;
The biomass (cell density) in the control cultures should have increased exponentially by a factor of at least 6 within 72 hours.
The mean coefficient of variation for daily specific growth rates (days 0-1, 1 -2, 2-3) in the control cultures must not exceed 35%.
The coefficient of variation of average specific growth rates during the whole exposure period (0-3 day) in the control cultures must not exceed 7%.

Results with reference substance (positive control):

The background data of the 0-72 hour ErCso value of the reference substance (potassium dichromate) in P subcapitata in the test laboratory were 1.4 and 1.2 mg/L (n=2, conducted in June and December 2009, NCAS No.; 09-059).

Any other information on results incl. tables

Temperature and light intensity in the incubator

The temperatures ranged from 22.9 to 23.0°C which were w ithin the acceptable range (23±2°C).

Measurements of light i ntensity ranged from 69 to 86 μE/m2/s which were within the acceptable range (65-100 μE/m2/s).

pH

The pH values of the control group at the start and end of the exposure were 8.0 and 7.9, respectively, and showed almost same value.

Observations o f test solutions

All test solutions were clear and colorless, and no coloration or precipitate due to the test substance was observed.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 72-hour growth inhibition study (open system, shaking culture) was performed by exposing the algae to the test solutions which contained Lithium bis=(fluorosulfone) imide (LiFSI). It is concluded that the 0-72 hour ErC50 values is > I00 mg/L and correspondingly the No Observed Effect Concentration (NOECr) is 50.0 mg/L on the basis of the nominal concentrations.

Executive summary:

A 72-hour growth inhibition study (open system, shaking culture) was performed by exposing the algae to test solutions containing Lithium=bis (fluorosulfone) imide (LiFSI). A 24.0% aqueous solution of LiFSI was used as a test substance and the concentrations of LiFSI were expressed as LiFSI itself unless otherwise specially stated. The measured concentrations of the test substance in the test solutions at 5 nominal concentrations of 6.25, 12.5, 25.0, 50.0 and 100 mg/L (common ratio: 2.0) were 104- 106 % of the nominal at the start of the exposure and 99.6- 103 % of the nominal at the end of the exposure. Since the variability of the measured concentrations was within ± 20% of the nominal, the results were calculated on the basis of the nominal concentrations as the test concentrations during the exposure period.

The concentration of the test substance that reduced algal growth by 50% (ErC50) and the No Observed Effect Concentration (NOECr) values based on the growth rate for the 0-72-hour exposure period are presented below:

Exposure duration	ErC50 (mg/L)	95 % confidence interval (mg/L)	NOECr (mg/L)
0 -72 hour	> 100*	-	50.0

*: Since the % inhibition was under 50% even at the highest test concentration (100 mg/L), the ErC50 was detennined > 100 mg/L.