Lithium bis[ethanedioato(2-)-κO1,κO2]difluorophosphate(1-)

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 2016-01-12 to 2016-01-27

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Batch No.: 150209
Purity: 97.7 wt%

Analytical monitoring:

yes

Details on sampling:

- Concentrations: five nominal loading rates of 15 mg/L, 17 mg/L, 19 mg/L, 22 mg/L and 25 mg/L water-accommodated fraction of test substance groups (the nominal loading rates of active constituent of 14.7 mg/L, 16.6 mg/L, 18.6 mg/L, 21.5 mg/L and 24.4 mg/L calculated by the 97.7% purity of test substance) and one blank control containing no test substance were set in the test.
- Sampling time: at 0 h, 48 h and 24 h (before and after the renewal) after the start of the test

Vehicle:

no

Details on test solutions:

Preparation of test solution: 25 mg test substance was obtained in a flask and dissolved in an amount of test medium, and then transferred into 1000 mL small mouth reagent bottle, diluted with test medium to 1000 mL to obtain the nominal loading rate of 25 mg/L test suspension. After that, the suspension was stirred with a magnetic stirrer for about 24 h. After stirring, the test suspension was stand for about 5 hours. Then the aqueous phase from the upper and middle layer was removed by siphoning, the nominal loading rate of 25 mg/L WAF (Water-accommodated fraction) solution was obtained. 22 mg, 19 mg, 17 mg and 15 mg test substance were obtained and prepared as the method above, respectively, the nominal loading rates of 22 mg, 19 mg, 17 mg and 15 mg WAF solutions were obtained.
Control: A blank control (test water without test substance)

Test organisms (species):

Daphnia magna

Details on test organisms:

- Reason for the selection: The test species is recommended by “The Guideline for Test of Chemicals”.
- Source: Safety Evaluation Center, Shenyang Research Institute of Chemical Industry. Apparently healthy, bred in our laboratory.
- Culture medium: Elendt M4
- Breeding and holding: test water: Elendt M4; water temperature: 20±2 °C; light and dark period: 16 h light / 8 h dark.
- Age: less than 24h old
- Number of the test daphnia: 120
- Sensitivity: The result of sensitivity test showed that 24h-EC50 of reference substance K2Cr207 is 1.25 mg/L within the range of 0.6 mg/L-2.1 mg/L. And the 95% confidence limits is 1.13 mg/L-1.38 mg/L.

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test temperature:

19.9-20.1 °C

pH:

7.63-8.91

Dissolved oxygen:

8.2 mg/L-9.8 mg/L

Nominal and measured concentrations:

five nominal loading rates of 15 mg/L, 17 mg/L, 19 mg/L, 22 mg/L and 25 mg/L water-accommodated fraction (abbreviated as WAF) of test substance groups (the nominal loading rates of active constituent of 14.7 mg/L, 16.6 mg/L, 18.6 mg/L, 21.5 mg/L and 24.4 mg/L calculated by the 97.7% purity of test substance).

Details on test conditions:

TEST SYSTEM
- No. of organisms: 5/test vessel, 120 in total
- No. of replicates : 4/test group
- No. of vessels per control (replicates): 5
- Volume of test solution: 50 mL/ test vessel

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: The test organisms were maintained and the tests conducted in Elendt M4 medium. The medium was prepared in deionised, distilled or reverse osmosis water.

OTHER TEST CONDITIONS
- Adjustment of pH: The test was performed with adjustment. The pH range of 7.63 to 8.91 within 6 to 9.
- Photoperiod: 16 h light /8 h dark
- intensity of illumination: 1121 lx and 1124 lx at the start and end of the test
- Feeding: not fed during the exposure

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : immobility at 24 and 48 hours

RANGE-FINDING STUDY
- Test concentrations: The nominal loading rates of 10 mg/L, 15 mg/L, 25 mg/L and 35 mg/L WAF (water-accommodated fraction) test groups and a blank control containing no test substance
- Results used to determine the conditions for the definitive study: The immobilities of blank control, nominal loading rate of 10 mg/L, 15 mg/L, 25 mg/L and 35 mg/L WAF test groups were 0%, 0%, 0%, 100% and 100%, respectively.

Reference substance (positive control):

yes

Remarks:

K2Cr2O7

Key result

Duration:

48 h

Dose descriptor:

EL0

Effect conc.:

< 15 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

18.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% confidence limits: 17.2 mg/L-19.3 mg/L

Key result

Duration:

48 h

Dose descriptor:

EL100

Effect conc.:

25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

lmmobility:
The test results revealed that immobilities of blank control at 24 h and 48 h after the start of the test were 0%, which were below than 10% and met the requirement.
Immobilities of the nominal loading rates of 15 mg/L, 17 mg/L, 19 m9/L, 22 mg/L and 25 mg/L WAF test groups at 24 h after the start of the test were 20%, 25%, 50%, 70% and 80% and the immobilities at 48 h after the start of the test were 20%, 30%, 50%, 85% and 100%, respectively.

Results with reference substance (positive control):

The 24 h-EC50 of reference substance K2Cr2O7 was 1. 251 mg/L with the 95% confidence limits of 1.13 mg/L-1.38 mg/L. The 24 h-EC50 of K2Cr2O7 was within the range of 0.6 mg/L-2.1 mg/L.

The measured concentrations of Lithium (Li) in test solutions:

The measured concentrations of Lithium in blank control were 0.0366 mg/L and 0.0288 mg/L at 0 h and 24 h (new solution) and were 0.0356 mg/L and 0.0763 mg/L at 24 h and 48 h (old solution). The measured concentrations of Lithium in the nominal loading rates of 15 mg/L, 171 mg/L, 19 mg/L, 22 mg/L and 25 mg/L WAF solution test groups at the start of the exposure and after the renewal ranged from 0.508 mg/L to 0.776 mg/L, equivalent to 109% - 119% of the nominal concentration of Li after removing the measured concentration of Li of blank control; and the measured concentrations of Li before the renewal and at the end of the exposure ranged from 0.502 mg/L to 0.778 mg/L, equivalent to 104% - 119% of the nominal concentration of Li after removing the measured concentration of Li of blank control. During 24h intervals, the measured concentrations of Li is stable and could be maintained within ±20% of the nominal concentration of Li.

The measured concentrations of oxalic ion (C2O42-) in test solutions:

The measured concentrations of oxalic ion in blank control were lower than the limit of detection (LOD = 0.006 mg/L) at 0 h and 24 h (old solution) after the start of the test.

The measured concentrations of oxalic ion in the nominal loading rates of 15 mg/L, 17 mg/L, 19 mg/L, 22 mg/L and 25 mg/L WAF solution test groups at the start of the exposure and after the renewal ranged from 1.46 mg/L to 1.63 mg/L, equivalent to 18% - 32% of the nominal concentration of oxalic ion; and the measured concentrations of oxalic ion before the renewal and at the end of the exposure ranged from 0.011 mg/L to 1.64 mg/L, equivalent to 0.2% - 32% of the nominal concentration of oxalic ion. During the test, the measured concentrations of oxalic ion are lower than 80% of the nominal concentration of oxalic ion, and it had a large variation in concentration during 24 h intervals.

Validity criteria fulfilled:

yes

Conclusions:

Based on the nominal loading rate of test substance, the highest loading rate causing 0% mobility (EL0) less than was less than 15 mg/L, the median effective loading rate (EL50) and the lowest loading rate causing 100% mobility (EL100) of Daphnia magna during 48h were respectively 18.3 mg/L and 25 mg/L.

Executive summary:

The test substance for its ability to generate acute toxic effects on the mobility of Daphnia magna was performed according to OECD Guideline 202.

Five nominal loading rates of 15 mg/L, 17 mg/L, 19 mg/L, 22 mg/L and 25 mg/L water-accommodated fraction of test substance groups were prepared. The test substance group was conducted as follows: 5 portions of 50mL of each concentration test solution were divided into the test vessels respectively, and the test daphnias were put into 4 portions to start the test. Another portion was used for measurement of water temperature, pH, dissolved oxygen concentration. A blank control (test water without test substance) was set in parallel to the test concentration.

The test results revealed that immobilities of blank control at 24h and 48h after the start of the test were 0%, which were below than 10% and met the requirement. Immobilities of the nominal loading rates of 15 mg/L, 17 mg/L, 19 mg/L, 22 mg/L and 25 mg/L WAF test groups at 24 h after the start of the test were 20%, 25%, 50%, 70% and 80% and the immobilities at 48 h after the start of the test were 20%, 30%, 50%, 85% and 100%, respectively.

The measured concentrations of Lithium in blank control were 0.0366 mg/L and 0.0288 mg/L at 0 h and 24 h (new solution) and were 0.0356 mg/L and 0.0763 mg/L at 24 h and 48 h (old solution). The measured concentrations of Lithium in the nominal loading rates of 15 mg/L, 17 mg/L, 19 mg/L, 22 mg/L and 25 mg/L WAF solution test groups at the start of the exposure and after the renewal ranged from 0.508 mg/L to 0.776 mg/L.

The measured concentrations of oxalic ion in blank control were lower than the limit of detection (LOD = 0.006 mg/L) at 0 h and 24 h (old solution) after the start of the test. The measured concentrations of oxalic ion in the nominal loading rates of 15 mg/L, 17 mg/L, 19 mg/L, 22 mg/L and 25 mg/L WAF solution test groups at the start of the exposure and after the renewal ranged from 1.46 mg/L to 1.63 mg/L.

Based on the nominal loading rate of test substance, the highest loading rate causing 0% mobility (EL0) less than was less than 15 mg/L, the median effective loading rate (EL50) and the lowest loading rate causing 100% mobility (EL100) of Daphnia magna during 48h were respectively 18.3 mg/L and 25 mg/L.

Description of key information

Based on the nominal loading rate of test substance, the highest loading rate causing 0% mobility (EL0) less than was less than 15 mg/L, the median effective loading rate (EL50) and the lowest loading rate causing 100% mobility (EL100) of Daphnia magna during 48h were respectively 18.3 mg/L and 25 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

18.3 mg/L

Additional information

The test substance for its ability to generate acute toxic effects on the mobility of Daphnia magna was performed according to OECD Guideline 202.

Five nominal loading rates of 15 mg/L, 17 mg/L, 19 mg/L, 22 mg/L and 25 mg/L water-accommodated fraction of test substance groups were prepared. The test substance group was conducted as follows: 5 portions of 50mL of each concentration test solution were divided into the test vessels respectively, and the test daphnias were put into 4 portions to start the test. Another portion was used for measurement of water temperature, pH, dissolved oxygen concentration. A blank control (test water without test substance) was set in parallel to the test concentration.

The test results revealed that immobilities of blank control at 24h and 48h after the start of the test were 0%, which were below than 10% and met the requirement. Immobilities of the nominal loading rates of 15 mg/L, 17 mg/L, 19 mg/L, 22 mg/L and 25 mg/L WAF test groups at 24 h after the start of the test were 20%, 25%, 50%, 70% and 80% and the immobilities at 48 h after the start of the test were 20%, 30%, 50%, 85% and 100%, respectively.

The measured concentrations of Lithium in blank control were 0.0366 mg/L and 0.0288 mg/L at 0 h and 24 h (new solution) and were 0.0356 mg/L and 0.0763 mg/L at 24 h and 48 h (old solution). The measured concentrations of Lithium in the nominal loading rates of 15 mg/L, 17 mg/L, 19 mg/L, 22 mg/L and 25 mg/L WAF solution test groups at the start of the exposure and after the renewal ranged from 0.508 mg/L to 0.776 mg/L.

The measured concentrations of oxalic ion in blank control were lower than the limit of detection (LOD = 0.006 mg/L) at 0 h and 24 h (old solution) after the start of the test. The measured concentrations of oxalic ion in the nominal loading rates of 15 mg/L, 17 mg/L, 19 mg/L, 22 mg/L and 25 mg/L WAF solution test groups at the start of the exposure and after the renewal ranged from 1.46 mg/L to 1.63 mg/L.

Based on the nominal loading rate of test substance, the highest loading rate causing 0% mobility (EL0) less than was less than 15 mg/L, the median effective loading rate (EL50) and the lowest loading rate causing 100% mobility (EL100) of Daphnia magna during 48h were respectively 18.3 mg/L and 25 mg/L.