Sodium bis(trifluoromethylsulfonyl)imide

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

October 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

For the substance SODIUM BIS(TRIFLUOROMETHYLSULFONYL)IMIDE a new chemical substance notification in China has been prepared under the Regulation ‘Measures on the Environmental Management of New Chemical Substances' (MEE Order No. 12 of the Ministry of Environmental Protection of the P.R. China, also known as ‘China REACH’). Under this regulation a short-term toxicity test in fish is part of the data requirements for substances that are produced or imported in volumes <10 t/y. For this reason a short-term toxicity test in fish was performed at Jiangsu Yaxin Tech. Co. Ltd. The results of the study were included in the dossier and serve as the valid testing for this endpoint.

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Purity: 99.9%

Analytical monitoring:

yes

Details on test solutions:

Solubility pre-test results showed that the solubility of the test substance in water was more than 1 g/L, and the stock solution method was adopted in the test.
In the range-finding test, 2.0022 g (0 h), 2.0020 g (24 h), 2.0022 g (48 h) and 2.0020 g (72 h) test substance were dissolved in 2 L test water, respectively. The stock solutions were agitated with speed of 500 rpm for 30 min at 25 ºC. The test stock solution of 1000 mg/L was prepared. Test substance was completely dissolved and the solution was colorless and clear.
In the limit test, 1.5017 g (0 h), 1.5017 g (24 h), 1.5016 g (48 h) and 1.5019 g (72 h) test substance were added into 1500 mL test water, respectively. The stock solutions were agitated with speed of 500 rpm for 30 min at 25 ºC. The test stock solution of 1000 mg/L was prepared. The test substance was completely dissolved and the solution was colorless and clear.

Test organisms (species):

other: Gobiocypris rarus

Details on test organisms:

TEST ORGANISM
- Common name: Rare minnow
- Strain: FG-20200704-S-001-06-05
- Source: commercial fish supplier of Institute of Hydrobiology, Chinese Academy of Sciences
- Length at study initiation (length definition, mean, range and SD): 3.805 cm, RSD 2.09%
- Weight at study initiation (mean and range, SD): 0.3954 g, RSD 3.45%

ACCLIMATION
- Acclimation period: 7 days
- Acclimation conditions: same as test
- Type and amount of food during acclimation: Brine Shrimp twice daily during the holding period, until approximately 24 hours before being placed into the test vessels
- Health during acclimation (any mortality observed): no mortality was observed

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

110 ~ 118 mg (CaCO3)/L

Test temperature:

23.1 ~ 23.7℃

pH:

7.69 ~ 7.86

Dissolved oxygen:

80.7% to 103.7% of the air saturation value

Nominal and measured concentrations:

nominal 120 mg/L
geometric mean measured concentration was 101 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: test tank with 10 L of test solution.
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 0.3954 g fish (wet weight) per litre of test medium

WATER PARAMETERS
- Intervals of water quality measurement: 24 h, 48 h, 72 h and 96 h

OTHER TEST CONDITIONS
- Photoperiod: 12 hours photoperiod daily
- Light intensity: 597 ~ 810 Lux

EFFECT PARAMETERS MEASURED: mortality, observation behaviour

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 1.20 mg/L, 12.0 mg/L and 120 mg/L
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

101 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 120 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

A control group was conducted under the same test condition. During the test period, no mortality was observed in the controls and fish in the control group were normal

Results with reference substance (positive control):

With the conditions maintained as designed for this test, potassium dichromate was used as the test substance and the resulting 24 h-LC50 was 264 mg/L.

Reported statistics and error estimates:

LC50 of reference substance and test substance and corresponding 95% confidence limits were calculated by Spearman-Karber method (Version 1.5, USEPA).
In this experiment, due to the low toxicity of the tested substance to fish, this statistical method was only used for the calculation of LC50 and 95% confidence limit of the reference substance.

Sublethal observations / clinical signs:

Mortality during the Range-finding Test

Nominal Concentration (mg/L)	Initial Number of Fish	The Number of the Dead Fish
		24 h	48 h	72 h	96 h
0 (blank control)	5	0	0	0	0
1.20	5	0	0	0	0
12.0	5	0	0	0	0
120	5	0	0	0	0

Mortality during the Limit Test

Nominal Concentration (mg/L)	Geometric Mean Measured Concentration (mg/L)	Initial Number of Fish	The Number of the Dead Fish
			24h	48 h	72 h	96 h
0 (blank control)	ND^①	10	0	0	0	0
120	101	10	0	0	0	0

Stability Test Results of Test Substance in Test Medium (Limit Test)

Nominal Concentration (mg/L)	Time (h)	Measured Concentration (mg/L)	Geometric Concentration^2 (mg/L)	Concentration Change Rate^3 (%)
0 (blank control)	0	ND^①	ND	-
	24-O	ND
	24-N	ND
	48-O	ND
	48-N	ND
	72-O	ND
	72-N	ND
	96	ND
120	0	122	101	-
	24-O	88.7		27.3
	24-N	115		-
	48-O	81.0		29.6
	48-N	125		-
	72-O	88.3		29.4
	72-N	118		-
	96	85		28.0

Note: 1- Less than the LOD of method (LOD =1.67 mg/L);

2- Geometric mean of measured concentration;

3-Concentration change rate = |spent sample measured concentration-fresh sample measured concentration|/ fresh sample measured concentration * 100%.

4- N- The fresh test solution after changed; O- The aged test solution before changed.

ND: Less than the LOD of method (LOD =1.67 mg/L).

Validity criteria fulfilled:

yes

Conclusions:

The results showed that under semi-static test conditions, the 96 h-LC50 of SODIUM BIS(TRIFLUOROMETHYLSULFONYL)IMIDE to fish (Rare minnow, Gobiocypris rarus) was greater than the concentration of 120 mg/L concentrations (geometric mean measured concentration was 101 mg/L), while the maximum concentration causing no mortality (96 h-LC0) was equal to the concentration of 120 mg/L concentrations (geometric mean measured concentration was 101 mg/L). i.e.:
96 h-LC50 >120 mg/L (geometric mean measured concentration was 101 mg/L);
96 h-LC0 =120 mg/L (geometric mean measured concentration was 101 mg/L).

Executive summary:

Under semi-static conditions, the acute toxicity of test substance was evaluated to Rare minnow (Gobiocypris rarus) according to the guidelines:“The guidelines for the testing of chemicals” (HJ/T 153-2004), “The Guidelines for the Testing of Chemicals-Effects on Biotic Systems” (the 2^nd edition. Beijing: China Environment Press. 2013); with reference to Procedure 203 of the “Guidelines for Testing of Chemicals” of the OECD: “Fish, Acute Toxicity Test” (2019).

A range-finding test and then a limit test was performed respectively. Nominal concentrations of 1.20 mg/L, 12.0 mg/L and 120 mg/L were used in the range-finding test, while the nominal concentration of 120 mg/L was used in the limit Test. In limit test (96 h), water samples taken from the control and the treatments in the limit test at 0, 96 h and 24, 48, 72 h before and after renewal were analysed by HPLC-MS/MS. During the limit test (96 h), the analytical results showed that the concentration of the test substance was in the range of 81.0 ~ 125 mg/L (the geometric mean measured concentration was 101 mg/L).

In the range-finding test, 5 fish per treatment and no replicate were used. And 10 fish per treatment with no replicate wereused in the limit test. The test fish were exposed for 96 hours to the test solution.

During the limit test, the loading rate was 0.3954 g wet weight fish per litre of test medium, the pH values of the control mediums and test mediums were between 7.69 to 7.86, the dissolved oxygen (DO) values varied from 80.7% to 103.7% of the air saturation, the temperature of the test mediums were maintained in the range of 23.1 ºC to 23.7 ºC, light intensity was 597 to 810 Lux, the total hardness was 110 ~ 118 mg (CaCO₃)/L, and all fish in the control group were normal. With the same conditions, potassium dichromate (K₂Cr₂O₇) was used as the positive control substance, and the resulting 24 h-LC₅₀ was 264 mg/L.

The results showed that under semi-static test conditions, the 96 h-LC₅₀ of the test substance to fish (Rare minnow, Gobiocypris rarus) was greater than the concentration of 120 mg/L concentration (geometric mean measured concentration was 101 mg/L), while the maximum concentration causing no mortality (96 h-LC₀) was equal to the concentration of 120 mg/L concentration (geometric mean measured concentration was 101 mg/L).

96 h-LC₅₀ >120 mg/L (geometric mean measured concentration was 101 mg/L);

96 h-LC₀ =120 mg/L (geometric mean measured concentration was 101 mg/L).

Description of key information

A recent reliable study on the target substance, NaTFSI, is available. Under semi-static conditions, the acute toxicity of test substance was evaluated to Rare minnow (Gobiocypris rarus) according to the guidelines:“The guidelines for the testing of chemicals” (HJ/T 153-2004), “The Guidelines for the Testing of Chemicals-Effects on Biotic Systems” (the 2^nd edition. Beijing: China Environment Press. 2013); with reference to Procedure 203 of the “Guidelines for Testing of Chemicals” of the OECD: “Fish, Acute Toxicity Test” (2019).

The results showed that the 96 h-LC₅₀ of the test substance to fish (Rare minnow, Gobiocypris rarus) was greater than the concentration of 120 mg/L concentration (geometric mean measured concentration was 101 mg/L), while the maximum concentration causing no mortality (96 h-LC₀) was equal to the concentration of 120 mg/L concentration (geometric mean measured concentration was 101 mg/L).

96 h-LC₅₀ >120 mg/L (geometric mean measured concentration was 101 mg/L);

96 h-LC₀ =120 mg/L (geometric mean measured concentration was 101 mg/L).

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

> 120 mg/L