Lithium [ethanedioato-O,O’]tetrafluorophosphate

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 2020-01-17 to 2020-02-24

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)

GLP compliance:

yes

Specific details on test material used for the study:

Batch No.: 190722
Purity: > 99 wt%

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Solutions containing 0, 4.6, 10, 22, 46 and 100% of the SS prepared at a loading rate of 100 mg/L.
- Sampling method: Two samples (2.0 mL and 4.8 mL from the approximate centre of the test solutions) per test group were taken for possible analysis at t=0 h and t=48 h
- Sample storage conditions before analysis: stored in a freezer (≤-15°C)

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Preparation of test solutions started with a loading rate of 100 mg/L applying an overnight period of magnetic stirring to ensure complete hydrolysis of the test item in medium. After adjusting the pH (range-finding test: from 3.2 to 6.5; final test: from 3.3 to 6.6) with 1 M sodium hydroxide solution (Merck, Darmstadt, Germany), the aqueous Saturated Solution (SS) was collected by filtration through a 0.45 µm membrane filter (RC55, Whatman) and used as the highest test concentration. Lower test concentrations were prepared by subsequent dilutions of the SS in test medium. All test solutions were clear and colorless at the end of the preparation procedure.
- Controls: Test medium without test item or other additives.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Strain/clone: Daphnia magna (Crustacea, Cladocera) (Straus, 1820)
- Age at study initiation (mean and range, SD): less than 24 hours old
- Valve height at study initiation, for shell deposition study (mean and range, SD):
- Source: In-house laboratory culture with a known history.
- Reason for selection: This system has been selected as an internationally accepted invertebrate species
- Age of parental stock (mean and range, SD): more than two weeks old
- Method of breeding
- Start of each batch: Approximately 250 newborn daphnids, i.e. less than 3 days old, were placed into 5 litres of medium in an all-glass culture vessel.
- Maximum age of the cultures: 4 weeks
- Renewal of the cultures: After 7 days of cultivation, half of the medium twice a week.
- Temperature of medium: 18-22°C
- Feeding: Daily, a suspension of fresh water algae.
- Culture medium:M7, as described by OECD 211 TG.
- Feeding during test: No feeding

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

180 mg/L as CaCO3

Test temperature:

19-21°C

pH:

At 0 h: 8.1
At 48 h: 7.7 - 8.0

Dissolved oxygen:

At 0 h: 9.1 - 9.7 mg/L
At 48 h: 8.6 - 8.8 mg/L

Nominal and measured concentrations:

Nominal: Solutions containing 4.6, 10, 22, 46 and 100% of the SS prepared at a loading rate of 100 mg/L.
Measured: 0.29, 0.62, 13, 31, 57 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 60 mL, all-glass.
- Volume of solution: 50 mL
- Aeration: No aeration
- Renewal rate of test solution: no renewal
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Biomass loading rate: 5 per vessel containing 50 mL of test solution

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: The following salts (analytical grade) were added to tap water purified by Reverse Osmosis (RO-water, GEON Waterbehandeling, Berkel-Enschot, The Netherlands): CaCl2.2H2O: 211.5 mg/L; MgSO4.7H2O: 88.8 mg/L; NaHCO3: 46.7 mg/L; KCl: 4.2 mg/L
- Culture medium different from test medium: yes, M7, as described by OECD 211 TG

OTHER TEST CONDITIONS
- Adjustment of pH: No adjustment
- Photoperiod: A daily photoperiod of 16 hours.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Immobility (including mortality): At 24 hours and at 48 hours.
- pH and dissolved oxygen: At the beginning and at the end of the test, for all concentrations and the control.
- Temperature of medium: Continuously in a temperature control vessel, beginning at the start of the test.

VEHICLE CONTROL PERFORMED: no

RANGE-FINDING STUDY
- Test concentrations: 0.10, 1.0 and 10 mg/L
- Results used to determine the conditions for the definitive study: No immobility was observed in the control and the two lowest test concentrations throughout the test. At 24 hours and at the end of the test, a dose-related increase of immobility was observed at 10 and 100 mg/L, reaching 100% immobility at the highest test concentration at the end of the test. During the exposure period, the concentrations remained stable based on the analysed results for Anion and Cation.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

11 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Immobility:
No immobility was observed in the control throughout the test. At 24 hours of exposure, no immobility was observed at the three lowest test concentrations, while 95 and 100% immobility were observed at 31 and 57 mg/L, respectively. At the end of the test, a dose-related increase of immobility was observed from 0.62 mg/L and higher, reaching 100% immobility at the two highest test concentrations.

- Measured Concentrations
- Anion:
Based on the anionic fraction of the test item, the measured concentrations at the start of the test were 0.27, 0.62, 13, 29 and 34 mg/L in solutions containing 4.6, 10, 22, 46 and 100% of the SS, respectively. During the exposure period, the four lowest concentrations remained stable, i.e. were at 102-116% relative to the initial concentrations at the end of the test. The highest test concentration showed a higher concentration at the end of the exposure period, which was confirmed after re-dilution and re-analysis of the according sample.
It is likely that the test item was not completely hydrolysed at the time of filtration and that a non-hydrolysed fraction passed through the filter, which hydrolysed completely upon dilution for the preparation of the lower test concentrations, but also over time in the undiluted SS.
- Cation:
Based on the cationic fraction of the test item, the measured concentrations at the start of the test were 5.1, 13, 25, 53 and 110 mg/L in solutions containing 4.6, 10, 22, 46 and 100% of the SS, respectively. During the exposure period, the concentrations remained stable, i.e. were at 91-99% relative to the initial concentrations at the end of the test.
- Defining exposure concentrations
Following a worst-case approach, the determination of effect parameters was subsequently based on the concentrations measured for the anionic form of the test item. Based on these results, the average exposure concentrations were calculated and used to express effect parameters.

Results with reference substance (positive control):

- Results with reference substance valid?
Yes, The batch of Daphnia magna tested, showed expected sensitivity to Potassium dichromate (Batch K50664264, Merck, Darmstadt, Germany).

Validity criteria fulfilled:

yes

Conclusions:

The 48h-EC50 for Daphnia magna exposed to test item was 11 mg/L based on average exposure concentrations (95% confidence interval between 5.6 and 15 mg/L).

Executive summary:

The ability of test item to generate acute toxic effects on the mobility of Daphnia magna during an exposure period of 48 hours was evaluated based on OECD 202.

A static test was performed with test solutions containing 4.6, 10, 22, 46 and 100% of the saturated Solution (SS), loading rate of 100 mg/L. A black control was set in parallel. 4 replicates with 5 daphnids were used for each test concentration.

The actual exposure concentrations were measured to be 0.29, 0.62, 13, 31, 57 mg/L.

No immobility was observed in the control throughout the test. At 24 hours of exposure, no immobility was observed at the three lowest test concentrations, while 95 and 100% immobility were observed at 31 and 57 mg/L, respectively. At the end of the test, a dose-related increase of immobility was observed from 0.62 mg/L and higher, reaching 100% immobility at the two highest test concentrations.

In conclusion, the 48h-EC50 for Daphnia magna exposed to test item was 11 mg/L based on average exposure concentrations (95% confidence interval between 5.6 and 15 mg/L).

Description of key information

The ability of test item to generate acute toxic effects on the mobility of Daphnia magna during an exposure period of 48 hours was evaluated based on OECD 202. The 48h-EC50 for Daphnia magna exposed to test item was 11 mg/L based on average exposure concentrations (95% confidence interval between 5.6 and 15 mg/L).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

11 mg/L