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

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 2016-03-16 to 2016-04-12

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Version / remarks:

2013

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Batch No.: 150209
Purity: 97.7wt%

Analytical monitoring:

yes

Details on sampling:

- Concentrations: the nominal loading rate of 1.0 mg/L, 1.7 mg/L, 2.8 mg/L, 4.8 mg/L and 8.0 mg/L water-accommodated fraction (abbreviated as WAF) of test substance test groups (the nominal loading rates of active constituent of 0.977 mg/L, 1.66 mg/L, 2.74 mg/L, 4.69 mg/L and 7.82 mg/L calculated by the 97.7% purity of test substance) and a blank control containing no test substance
- Sampling time:
- Analysis of the actual concentration of Lithium in test solutions: measured at the start of the test, after and before the renewal solution every time and at the end of the test
- Analysis of the actual concentration of oxalic ion in test solutions: measured at the start of the test, after and before the renewal solution every time and at the end of the test; The blank control was measured at 0 d (new solution) and 1d (old solution).

Vehicle:

no

Details on test solutions:

Preparation of the test solution
24.0 mg test substance was obtained in a flask and dissolved in a small amount of test medium, and then transferred into 5L-jar, diluted with test medium to 3000 mL to obtain the nominal loading rate of 8.0 mg/L test suspension. After that, the suspension was stirred with a magnetic stirrer for about 24h (the depth of vortex was l cm-2 cm). 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 first approximated 100-200 mL was discarded), the nominal loading rate of 8.0 mg/L WAF (water-accommodated fraction) solution was obtained. 14.4mg, 8.4mg, 5.1mg and 3.0 mg test substance were obtained and prepared as the method above respectively, the nominal loading rates of 4.8mg, 2.8mg, 1.7mg and 1.0mg WAF solutions were obtained.

Preparation of the test system
Test medium was divided into 10 test vessels, respectively, and the volume of test medium was 80mL each test vessel as blank control group. The nominal loading rate of 1.0mg/L, 1.7mg/L, 2.8mg/L, 4.8mg/L and 8.0mg/L WAF test solutions were divided into 10 test vessels, respectively, and the volume of test medium was 80 mL each test vessel as test substance groups and 1 animal each vessel.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Age at study initiation (mean and range, SD): The animals were less than 24 hours old and were not first brood progeny.
- Feeding during test
- Food type: a concentrated algal suspension
- Amount: The diet of the parent animals was about 0.1 mg C/Daphnia/day - 0.2 mg C/Daphnia/day.
- Frequency: daily during the exposure

Food
- Food type: Scenedesmus obliquus
- Condition of culture: Temperature (23 °C ± 2 °C), 24h continuously light, illumination intensity (4440 lx-8880 1x).

ACCLIMATION
- Acclimation conditions: acclimated in the testing laboratory for one generation at least under the same conditions of water quality (Elendt M4 medium), temperature (20 °C ± 2 °C), light and dark period (16h light / 8h dark), illumination intensity (600 lx -1500 lx)
- Type and amount of food: fed with a concentrated algal suspension.

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

21 d

Hardness:

240 mg/L - 265 mg/L.

Test temperature:

18.8 °C - 20.6 °C.

pH:

7.72 - 7.90

Dissolved oxygen:

8.0 mg/L - 9.3 mg/L

Nominal and measured concentrations:

The nominal loading rate of 1.0 mg/L, 1.7 mg/L, 2.8 mg/L, 4.8 mg/L and 8.0 mg/L water-accommodated fraction (abbreviated as WAF) of test substance test groups (the nominal loading rates of active constituent of 0.977 mg/L, 1.66 mg/L, 2.74 mg/L, 4.69 mg/L and 7.82 mg/L calculated by the 97.7% purity of test substance)

Details on test conditions:

TEST SYSTEM
- Test vessel: 150 mL beaker
- Aeration: no
- Renewal rate of test solution (frequency/flow rate): renewal at every 24 h
- Volume of test solution: 80 mL / test vessel
- No. of replicates per concentration:10
- No. of replicates per control: 10

TEST MEDIUM: Elendt M4 medium

OTHER TEST CONDITIONS
- Photoperiod: 16h light / 8h darkness
- Light intensity: Illumination intensity average at the start and end of the test were 1116 lx and 1099 lx.

EFFECT PARAMETERS MEASURED
- Observation, mortality and body length of parent daphnias
The appearance and mortality of parent daphnias were recorded daily. At the end of the test, the body length of each surviving parent daphnias (anal spine not included) was determined using digital caliper.
- The number of live offspring
The live offspring produced by each parent animal was removed and counted daily, and also the presence of dead offspring and aborted eggs were recorded.

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: The nominal loading rate of 2 mg/L, 5 mg/L, 10 mg/L and 20 mg/L water-accommodated fraction (abbreviated as WAF) of test substance groups and a blank control were selected.
- Results used to determine the conditions for the definitive study: No statistically significant differences between the 2 mg/L WAF test group and the blank control at 14d (p > 0.05); the number of living offspring in 5 mg/L, 10 mg/L and 20 mg/L WAF test groups had significant differences with blank control (p ≤ 0.05).

Reference substance (positive control):

no

Key result

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

5.62 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

1.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

1.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: body length

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

4.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: mortality of parent animals

Key result

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

2.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Key result

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

2.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: body length

Key result

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: mortality of parent animals

Details on results:

- Observations of parent animals
During test period, there was no abnormal color and responses of parent animals in blank control and all test substance groups.
The time presence of the first eggs in the brood pouch in blank control and the nominal loading rate of 1.0 mg/L, 1.7 mg/L, 2.8 mg/L, 4.8 mg/L and 8.0 mg/L test substance groups were all 5.0 ± 0.0d, and the time to production of first brood in blank: control and all test substance groups were 7.9 ± 0.4d, 8.0 ± 0.0d, 8.0 ± 0.0d, 8.0 ± 0.0d, 8.0 ± 0.0d and 8.2 ± 0.7d, respectively.
- Mortality rate of parent animals
At the end of the test, there were no parent animal dead in the control group, which met the quality requirement that the mortality of the parent animals (female Daphnia) should not exceed 20% at the end of the test.
At the end of the test, the mortality of parent animals in nominal loading rate of 1.0 mg/L, 1.7 mg/L, 2.8 mg/L, 4.8 mg/L and 8.0 mg/L test groups were 0%, 0%, 0%, 20% and 40%. There was no statistically significant difference (p > 0.05) between blank control and 1.0 mg/L, 1.7 mg/L and 2.8 mg/L test substance groups, and 4.8 mg/L and 8.0 mg/L test substance groups had significant difference with blank control (p ≤ 0.05) in terms of the mortality of parent animals. So according to the mortality of parent animal, LOEL was 8.0 mg/L (based on nominal loading rate WAF), NOEL was 4.8 mg/L (based on nominal loading rate WAF).
- Body length of the parent animals
At the end of the test, there was no statistically significant difference (p > 0.05) between 1.0 mg/L and 1.7 mg/L test groups and blank control in terms of body length by Dunnett's test. 2.8 mg/L, 4.8 mg/L and 8.0 mg/L test groups had significant difference (p ≤ 0.05) with bank control in terms of body length. So according to the body length of the parent animals, LOEL was 2.8 mg/L (based on nominal loading rate WAF), NOEL was 1.7 mg/L (based on nominal loading rate WAF).
- Living offspring by each parent animal
At the end of the test, the mean ± SD of reproductive output of the control group was 109 ± 5 offspring per surviving parent animal. The coefficient of variation in the control group was 4%.
No dead offspring and aborted broods were observed in blank control and nominal loading rate of 1.0 mg/L, 1.7 mg/L, 2.8 mg/L, 4.8 mg/L and 8.0 mg/L test groups during the test.
The total number of living offspring produced per surviving parent animal in each concentration of the test substance were estimated by Dunnett's test. The results revealed that there was no statistically significant difference (p > 0.05) between blank control and 1.0 mg/L and 1.7 mg/L test groups, and 2.8 mg/L, 4.8 mg/L and 8.0 mg/L test groups had significant difference with blank control (p ≤ 0.05) in terms of the number of living offspring produced per adult. So according to the reproductive output, LOEL was 2.8mg/L (based on nominal loading rate WAF), NOEL was 1.7 mg/L (based on nominal loading rate WAF).
According to the effects on reproduction, the EL50 of Daphnia magna 5.62 mg/L and the 95% confidence limits ranged from 4.41 mg/L to 6.33 mg/L calculated by A Linear Interpolation Method (based on nominal loading rate WAF).

The measured concentrations of Lithium in test solutions

The measured concentrations of Lithium in blank control ranged from 0.0312 mg/L and 0.05361 mg/L at the start of the exposure and after the renewal and ranged from 0.0357 mg/L to 0.0546 mg/L before the renewal and at the end of the exposure.

The measured concentrations of Lithium in the nominal loading rates of 1.0 mg/L, 1.7 mg/L, 2.8 mg/L, 4.8 mg/L and 8.0 mg/L WAF solution test groups at the start of the exposure and after the renewal ranged from 0.0523 mg/L to 0.301mg/L, equivalent to 51 % - 133% 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 0.0502 mg/L to 0 .2 95 mg/L, equivalent to 35% - 122% of the nominal concentration of Li after removing the measured concentration of Li of blank control. During 24h intervals, the measured concentrations of Li of higher concentration test groups (2.8 mg/L, 4.8 mg/L and 8.0 mg/L) were mostly maintained within ± 20% of the nominal concentration of Li, but a part of the measured concentrations of Li of lower concentration test groups (1.0 mg/L and 1.7 mg/L) were lower than 80% of the nominal concentration of Li.

The measured concentrations of oxalic ion 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 0h and 24h (old solution) after the start of the test.

The measured concentrations of oxalic ion in the nominal loading rates of 1.0 mg/L, 1.7 mg/L, 2.8 mg/L, 4.8 mg/L and 8.0 mg/L WAF solution test groups at the start of the exposure and after the renewal ranged from < 0.006 mg/L (LOD) to 3.92 mg/L, equivalent to 0% - 193% 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 < 0.006 mg/L (LOD) to 3.42 mg/L, equivalent to 0% - 176% of the nominal concentration of oxalic ion. During the test, the measured concentrations of oxalic ion could not be maintained within ± 20% of the nominal concentration of oxalic ion during 24h intervals, there is not any law for concentration change.

Validity criteria fulfilled:

yes

Conclusions:

According to the effects on reproduction, the EL50 of Daphnia magna is 5.62 mg/L and the 95% confidence limits ranged from 4.41 mg/L to 6.33 mg/L (based on nominal loading rate WAF). 21d lowest observed effect loading rate (LOEL) for effects on reproduction, effects on body length, mortality of parent animals were 2.8 mg/L, 2.8 mg/L, 8.0 mg/L (based on nominal loading rate WAF), respectively. 21d no observed effect loading rate (NOEL) for effects on reproduction, effects on body length, mortality of parent animals were 1.7 mg/L, 1.7 mg/L, 4.8 mg/L (based on nominal loading rate WAF), respectively.

Executive summary:

The test is to assess the effect of test substance on the reproductive output of Daphnia magna according toOECD Guideline 211 (Daphnia magna Reproduction Test).

The nominal loading rate of 1.0 mg/L, 1.7 mg/L, 2.8 mg/L, 4.8 mg/L and 8.0 mg/L water-accommodated fraction (abbreviated as WAF) of test substance test groups (the nominal loading rates of active constituent of 0.977 mg/L, 1.66 mg/L, 2.74 mg/L, 4.69 mg/L and 7.82 mg/L calculated by the 97.7% purity of test substance) and a blank control containing no test substance were selected.

 

The measured concentrations of Lithium in blank control ranged from 0.0312 mg/L and 0.05361 mg/L at the start of the exposure and after the renewal and ranged from 0.0357 mg/L to 0.0546 mg/L before the renewal and at the end of the exposure.

The measured concentrations of Lithium in the nominal loading rates of 1.0 mg/L, 1.7 mg/L, 2.8 mg/L, 4.8 mg/L and 8.0 mg/L WAF solution test groups at the start of the exposure and after the renewal ranged from 0.0523 mg/L to 0.301mg/L, equivalent to 51 % - 133% 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 0.0502 mg/L to 0 .2 95 mg/L, equivalent to 35% - 122% of the nominal concentration of Li after removing the measured concentration of Li of blank control. During 24h intervals, the measured concentrations of Li of higher concentration test groups (2.8 mg/L, 4.8 mg/L and 8.0 mg/L) were mostly maintained within ± 20% of the nominal concentration of Li, but a part of the measured concentrations of Li of lower concentration test groups (1.0 mg/L and 1.7 mg/L) were lower than 80% of the nominal concentration of Li.

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

The measured concentrations of oxalic ion in the nominal loading rates of 1.0 mg/L, 1.7 mg/L, 2.8 mg/L, 4.8 mg/L and 8.0 mg/L WAF solution test groups at the start of the exposure and after the renewal ranged from < 0.006 mg/L (LOD) to 3.92 mg/L, equivalent to 0% - 193% 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 < 0.006 mg/L (LOD) to 3.42 mg/L, equivalent to 0% - 176% of the nominal concentration of oxalic ion. During the test, the measured concentrations of oxalic ion could not be maintained within ± 20% of the nominal concentration of oxalic ion during 24h intervals, there is not any law for concentration change.

 

According to the effects on reproduction, the EL50 of Daphnia magna is 5.62 mg/L and the 95% confidence limits ranged from 4.41 mg/L to 6.33 mg/L (based on nominal loading rate WAF). 21d lowest observed effect loading rate (LOEL) for effects on reproduction, effects on body length, mortality of parent animals were 2.8 mg/L, 2.8 mg/L, 8.0 mg/L (based on nominal loading rate WAF), respectively. 21d no observed effect loading rate (NOEL) for effects on reproduction, effects on body length, mortality of parent animals were 1.7 mg/L, 1.7 mg/L, 4.8 mg/L (based on nominal loading rate WAF), respectively.

Description of key information

According to the effects on reproduction, the EL50 of Daphnia magna is 5.62 mg/L and the 95% confidence limits ranged from 4.41 mg/L to 6.33 mg/L (based on nominal loading rate WAF). 21d lowest observed effect loading rate (LOEL) for effects on reproduction, effects on body length, mortality of parent animals were 2.8 mg/L, 2.8 mg/L, 8.0 mg/L (based on nominal loading rate WAF), respectively. 21d no observed effect loading rate (NOEL) for effects on reproduction, effects on body length, mortality of parent animals were 1.7 mg/L, 1.7 mg/L, 4.8 mg/L (based on nominal loading rate WAF), respectively.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1.7 mg/L

Additional information

The test is to assess the effect of test substance on the reproductive output of Daphnia magna according toOECD Guideline 211 (Daphnia magna Reproduction Test).

The nominal loading rate of 1.0 mg/L, 1.7 mg/L, 2.8 mg/L, 4.8 mg/L and 8.0 mg/L water-accommodated fraction (abbreviated as WAF) of test substance test groups (the nominal loading rates of active constituent of 0.977 mg/L, 1.66 mg/L, 2.74 mg/L, 4.69 mg/L and 7.82 mg/L calculated by the 97.7% purity of test substance) and a blank control containing no test substance were selected.

 

The measured concentrations of Lithium in blank control ranged from 0.0312 mg/L and 0.05361 mg/L at the start of the exposure and after the renewal and ranged from 0.0357 mg/L to 0.0546 mg/L before the renewal and at the end of the exposure.

The measured concentrations of Lithium in the nominal loading rates of 1.0 mg/L, 1.7 mg/L, 2.8 mg/L, 4.8 mg/L and 8.0 mg/L WAF solution test groups at the start of the exposure and after the renewal ranged from 0.0523 mg/L to 0.301mg/L, equivalent to 51 % - 133% 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 0.0502 mg/L to 0 .2 95 mg/L, equivalent to 35% - 122% of the nominal concentration of Li after removing the measured concentration of Li of blank control. During 24h intervals, the measured concentrations of Li of higher concentration test groups (2.8 mg/L, 4.8 mg/L and 8.0 mg/L) were mostly maintained within ± 20% of the nominal concentration of Li, but a part of the measured concentrations of Li of lower concentration test groups (1.0 mg/L and 1.7 mg/L) were lower than 80% of the nominal concentration of Li.

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

The measured concentrations of oxalic ion in the nominal loading rates of 1.0 mg/L, 1.7 mg/L, 2.8 mg/L, 4.8 mg/L and 8.0 mg/L WAF solution test groups at the start of the exposure and after the renewal ranged from < 0.006 mg/L (LOD) to 3.92 mg/L, equivalent to 0% - 193% 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 < 0.006 mg/L (LOD) to 3.42 mg/L, equivalent to 0% - 176% of the nominal concentration of oxalic ion. During the test, the measured concentrations of oxalic ion could not be maintained within ± 20% of the nominal concentration of oxalic ion during 24h intervals, there is not any law for concentration change.

 

According to the effects on reproduction, the EL50 of Daphnia magna is 5.62 mg/L and the 95% confidence limits ranged from 4.41 mg/L to 6.33 mg/L (based on nominal loading rate WAF). 21d lowest observed effect loading rate (LOEL) for effects on reproduction, effects on body length, mortality of parent animals were 2.8 mg/L, 2.8 mg/L, 8.0 mg/L (based on nominal loading rate WAF), respectively. 21d no observed effect loading rate (NOEL) for effects on reproduction, effects on body length, mortality of parent animals were 1.7 mg/L, 1.7 mg/L, 4.8 mg/L (based on nominal loading rate WAF), respectively.