Lithium bis(oxalato)borate

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:

2016-01-19 - 2016-03-21

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:

2012

Deviations:

yes

Remarks:

different feeding, hardness measurement; There were no deviations from standard operating procedures that affected the integrity of the study.

GLP compliance:

yes

Specific details on test material used for the study:

No correction factor for purity/composition required.

Analytical monitoring:

yes

Details on sampling:

- Sampling method: Singular samples for analysis were taken from all test concentrations and the control. At the end of the refreshment period, the replicates were pooled at each concentration before sampling. already used, these samples were stored in a freezer for a maximum of three months after delivery of the draft report, pending on the decision of the sponsor for additional analysis.
- Frequency: At the beginning and at the end of three intervals of 48 hours (nominal days 0 and 2, 6 and 8, 14 and 16).
- Volume: 4.8 mL
- Sample storage conditions before analysis: Samples were stored in a freezer (≤ -15°C) until analysis.

Vehicle:

yes

Remarks:

water, 507 – 1015 g/L at 20°C and pH 1.3 (hydrolysis)

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: stirring, pH adjustment to 8.5
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): water
- Concentration of vehicle in test medium (stock solution and final test solution(s) or suspension(s) including control(s)):
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): dispersions were filtered through a rough paper filter (~5 μm; Whatman 597) to remove any precipitate

The resulting Saturated Solutions (SS) were clear and colourless, and used as highest test concentration. Lower test concentrations were prepared by subsequent dilutions of the SS. All final test solutions were clear and colourless and renewed every second day during the study period.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna (Crustacea, Cladocera)
- Strain/clone: Straus, 1820
- Source: In-house laboratory culture with a known history.
- Age of parental stock (mean and range, SD): at least third generation, obtained by acyclical parthenogenesis under specified breeding conditions. 2nd to 5th brood. To initiate the test, young daphnids < 24 hours old were selected, from parental daphnids greater than two weeks old.
- Feeding during test: yes
- Food type: suspension of fresh water algae
- Frequency: daily
- Light: 16 h photoperiod daily; intensity at the start: 657-888 lux, intensity at the end: 697-816 lux

ACCLIMATION
- Acclimation period: not needed, in-house breeding
- Acclimation conditions (same as test or not): same, Medium M7
- Health during acclimation (any mortality observed): no mortalities
- Feeding: Twice daily an amount of 0.25 mg C/daphnia/day in a form of Chlorella pyrenoidosa suspension combined with Marinure (TOC ratio of this mixture was 5:1). On weekend days an amount of 0.50 mg C/daphnia/day was added in one single feed.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Hardness:

180 mg/L CaCO3

Test temperature:

18 - 22°C

pH:

7.7 +/- 0.3

Dissolved oxygen:

not specified

Salinity:

not specified

Conductivity:

not specified

Nominal and measured concentrations:

1.0, 3.2, 10, 32 and 100% of a saturated solution (SS) prepared at a loading rate of 100 mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel: all-glass
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: glass, 60 ml (6 x Ø 3.5 cm)
- Renewal rate of test solution (frequency/flow rate): every 48h
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 20

TEST MEDIUM / WATER PARAMETERS
Adjusted ISO medium: the following chemicals (analytical grade) are dissolved in tap water purified by Reverse Osmosis (ROwater, GEON Waterbehandeling, Berkel-Enschot, The Netherlands):
Macro salts:
CaCl2.2H2O 211.5 mg/L
MgSO4.7H2O 88.8 mg/L
NaHCO3 46.7 mg/L
KCl 4.2 mg/L
Medium M7: trace elements, macro nutrients and vitamins are added to freshly prepared ISO medium to reach the following concentrations:
Trace elements:
B 0.125 mg/L
Fe 0.05 mg/L
Mn 0.025 mg/L
Li, Rb and Sr 0.0125 mg/L
Mo 0.0063 mg/L
Br 0.0025 mg/L
Cu 0.0016 mg/L
Zn 0.0063 mg/L
Co and I 0.0025 mg/L
Se 0.0010 mg/L
V 0.0003 mg/L
Na2EDTA.2H2O 2.5 mg/L
Macro nutrients:
Na2SiO3. 9H2O 10.0 mg/L
NaNO3 0.27 mg/L
KH2PO4 0.14 mg/L
K2HPO4 0.18 mg/L
Vitamins: Thiamine 75.0 μg/L
B12 1.0 μg/L
Biotin 0.75 μg/L

The hardness: 180 mg/L expressed as CaCO3 and the pH: 7.7 ± 0.3.

OTHER TEST CONDITIONS
- Adjustment of pH: yes, to 7.7 ± 0.3.
- Photoperiod:16 h photoperiod daily;
- Light intensity: intensity at the start: 657-888 lux; intensity at the end: 697-816 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Parental daphnids
- Condition: Every workday and upon renewal on non-workdays, the number of living, immobile and dead parental daphnids was recorded. Dead daphnids were removed when observed.
- Presence of eggs in the brood pouch: Every workday and upon renewal on non-workdays.
- Body length: At the end of the test.
Offspring
- Appearance first brood: When observed.
- Newborn daphnids: Every workday and upon renewal on non-workdays, the number of newborn young was counted and the condition of the young recorded. Thereafter, the young were removed.
- Presence of unhatched eggs: When observed.
- Incidence of immobility: When observed.
Test medium
- Temperature, oxygen and pH: At the start of the test and just before and after each renewal in one of the vessels of each test group with surviving daphnids.
- Hardness: Once a week in fresh and old media from the control and the highest test concentration
- Light: At the start and the end of the test

TEST CONCENTRATIONS
- Test concentrations: 1.0, 3.2, 10, 32 and 100% of a SS prepared at a loading rate of 100 mg/L.
- Spacing factor: 3.2
- Range finding study
- Test concentrations: 1.0, 10 and 100% of a SS prepared at a loading rate of 100 mg/L and one control group.
Each concentration consisted of two replicates containing a total of ten daphnids (five each). The total test period was ten days. Test conditions were kept as similar as possible to those applied in the reproduction test including feeding. Test solutions were renewed every 2nd day during the test. Samples for analyses of actual exposure concentrations were not taken.
- Results used to determine the conditions for the definitive study: percent mortality was observed at both 10 and 100% SS. A significant reduction of reproduction was observed in each of the three concentrations tested. It should be highlighted that a high variation between duplicates was observed indicating that the number of broods might be different between replicates. In addition, dose-unrelated immobility of offspring was recorded in this test. The results of the range-finding test should thus be interpreted with care. Nevertheless, it was decided to continue testing with a main study covering a rather broad range of concentrations including 1.0, 3.2, 10, 32 and 100% SS (spacing factor 3.2).

Reference substance (positive control):

no

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

reproduction

Key result

Duration:

21 d

Dose descriptor:

EC10

Effect conc.:

29 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mortality

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Details on results:

- Behavioural abnormalities: no
- Observations on body length and weight: Statistically significant reduction of growth was found for the two highest test groups. Hence, the NOEC for growth equalled the test group containing 10% SS.
- Other biological observations: no
- Mortality of control: no mortalities observed
- Other adverse effects control: no
- Abnormal responses: no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no
- Effect concentrations exceeding solubility of substance in test medium: no

Reported statistics and error estimates:

EC VALUES: REPRODUCTION
Stop Reason = Iterations > Max. Iterations (Optimization method: Levenberg-Marquardt)
R²: 0.711; adjusted R²: 0.702
Residual standard error: 18.94229
Akaike Criterion (AIC): 480.471
Shapiro Wilk`s test on normal distribution of residuals: p = 0.583.

STATISTICS: REPRODUCTION
Number of residuals = 60
Shapiro-Wilk´s W = 0.977
p(W) = 0.309
p(W) is greater than the selected significance level of 0.010; thus treatment data do not
significantly deviate from normal distribution.
Normality check was passed (p > 0.01).

STATISTICS: BODY LENGTH
Number of residuals = 27
Shapiro-Wilk´s W = 0.526
p(W) = <0.001
p(W) is smaller than or equal to the selected significance level of 0.010; therefore, treatment
data significantly differ from normal distribution.
Normality check failed (p <= 0.01).

STATISTICS: AGE AT FIRST REPRODUCTION
Number of residuals = 16
Shapiro-Wilk´s W = 0.890
p(W) = 0.055
p(W) is greater than the selected significance level of 0.010; thus treatment data do not
significantly deviate from normal distribution.
Normality check was passed (p > 0.01).

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the present study, Lithium-bis(oxalate) borate (LiBOB) did not affect reproduction of Daphnia magna in a test group containing 10% of a saturated solution prepared at a loading rate of 100 mg/L after 21 days of exposure (NOEC). Based on the measured Lithium concentration this was expected to correspond with 10 mg/L of test item. The EC10 (21days) for reproduction was calculated to be in the range of 19-43 mg/L (29 mg/L) nominal.

Executive summary:

The chronic toxicity of Lithium-bis(oxalate) borate (LIBOB) towards Daphnia magna has been investigated in an 21 -day Reproduction Test according to OECD Guideline 211 and in compliance with GLP criteria. The test item was not completely soluble in test medium at the initial prepared concentration of 100 mg/L and therefore the hazy dispersions were filtered through a rough paper filter to remove any precipitate. The resulting Saturated Solutions (SS) were clear and colourless, and used as the highest test concentration. Lower test concentrations were prepared by subsequent dilutions of the SS. All final test solutions were clear and colourless.

The reproduction test was performed in a semi-static system and comprised of 10 vessels per test concentration and 20 vessels for an untreated control group. Each of the vessels contained one neonate (<24h old) Daphnia magna in 50 ml test medium. The Lithium-bis(oxalate) borate (LiBOB) groups tested contained 1.0, 3.2, 10, 32 and 100% of an SS prepared at a loading rate of 100 mg/L. The study duration was 21 days and the test solutions were renewed every 48 hours. The daphnids were fed on a daily basis with a Chlorella pyrenoidosa/Marinure suspension. Every workday, the condition of the parental daphnids was recorded, and during the reproduction phase, the number of living offspring, immobile young and appearance of unhatched (aborted) eggs was recorded. At the end of the test, the lengths of the surviving parental daphnids were measured.

During the study, samples for chemical analyses were taken at the beginning and the end of three intervals of 48 hours. Analyses were based on Lithium concentrations and the measured concentrations were in agreement with concentrations expected based on the theoretical fraction of Lithium (3.57%), the applied loading rate and the respective dilution factor. The measured Lithium concentrations remained stable during the 48-hour renewal intervals. Results were based on both the loading rate, and percentages thereof, and based on the expected concentration in solution (based on Li measurements). Measurement of Lithium is indicative of the remaining Lithium-bis(oxalate)borate concentration present in the test solutions.

No statistically significant mortality was observed at any of the concentrations tested.

The onset of reproduction was significantly affected at the highest concentration tested.

The number of produced offspring and the growth of the parental daphnids were significantly affected at the two highest concentrations tested.

The study met the acceptability criteria prescribed by the study plan and was considered valid.

The NOEC for reproduction has been determined to be 10 mg/L nominal and the EC₁₀ for reproduction has been determined to be in the range of 19-43 mg/L nominal (19 mg/L nominal), respectively.

The EC₅₀ for reproduction was > 100 mg/L nominal, NOEC mortality was 10 mg/L and NOEC growth was 10 mg/L.

Description of key information

Lithium bis(oxalato)borate did not reveal chronic toxicity to Daphnia magna in a semi-static test resulting in a 21d EC10 of 19 mg/L. The corresponding NOEC is 10 mg/L, respectively.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

19 mg/L

Additional information

The chronic toxicity of Lithium-bis(oxalate) borate (LIBOB) towards Daphnia magna has been investigated in an 21 -day Reproduction Test according to OECD Guideline 211 and in compliance with GLP criteria. The test item was not completely soluble in test medium at the initial prepared concentration of 100 mg/L and therefore the hazy dispersions were filtered through a rough paper filter to remove any precipitate. The resulting Saturated Solutions (SS) were clear and colourless, and used as the highest test concentration. Lower test concentrations were prepared by subsequent dilutions of the SS. All final test solutions were clear and colourless.

The reproduction test was performed in a semi-static system and comprised of 10 vessels per test concentration and 20 vessels for an untreated control group. Each of the vessels contained one neonate (<24h old) Daphnia magna in 50 ml test medium. The Lithium-bis(oxalate) borate (LiBOB) groups tested contained 1.0, 3.2, 10, 32 and 100% of an SS prepared at a loading rate of 100 mg/L. The study duration was 21 days and the test solutions were renewed every 48 hours. The daphnids were fed on a daily basis with a Chlorella pyrenoidosa/Marinure suspension. Every workday, the condition of the parental daphnids was recorded, and during the reproduction phase, the number of living offspring, immobile young and appearance of unhatched (aborted) eggs was recorded. At the end of the test, the lengths of the surviving parental daphnids were measured.

During the study, samples for chemical analyses were taken at the beginning and the end of three intervals of 48 hours. Analyses were based on Lithium concentrations and the measured concentrations were in agreement with concentrations expected based on the theoretical fraction of Lithium (3.57%), the applied loading rate and the respective dilution factor. The measured Lithium concentrations remained stable during the 48-hour renewal intervals. Results were based on both the loading rate, and percentages thereof, and based on the expected concentration in solution (based on Li measurements). Measurement of Lithium is indicative of the remaining Lithium-bis(oxalate)borate concentration present in the test solutions.

No statistically significant mortality was observed at any of the concentrations tested.

The onset of reproduction was significantly affected at the highest concentration tested.

The number of produced offspring and the growth of the parental daphnids were significantly affected at the two highest concentrations tested.

The study met the acceptability criteria prescribed by the study plan and was considered valid.

The NOEC for reproduction has been determined to be 10 mg/L nominal and the EC₁₀ for reproduction has been determined to be in the range of 19-43 mg/L nominal (19 mg/L nominal), respectively.

The EC₅₀ for reproduction was > 100 mg/L nominal, NOEC mortality was 10 mg/L and NOEC growth was 10 mg/L.