Borate(1-), bis[ethanedioato(2-)-.kappa.O1,.kappa.O2]-, potassium (1:1), (T-4)-

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2004-09-20 to 2004-10-14

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2004

Report date:

2004

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

, directive 92/69, publication no. L383, December 1992

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

, adopted 1984-04-04

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

244761-29-3

EC Number:

607-383-9

Cas Number:

244761-29-3

IUPAC Name:

244761-29-3

Constituent 2

Reference substance name:

Lithium bis(oxalato)borate

EC Number:

456-990-3

EC Name:

Lithium bis(oxalato)borate

IUPAC Name:

lithium bis(oxalato)borate

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

SMILES: O=C1O[B-]2(OC1=O)OC(=O)C(=O)O2.[Li+]

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Sampling:
Frequency: 1 . At the start of the test and after 24 hours from the freshly prepared solutions. 2. At the first renewal (t=24h) and the end of the test from the 24-hour old solutions.
Volume: 20 ml from the approximate centre of the test vessel.
Storage: Samples were stored at room temperature.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

Preparation of test solutions started with a stock solution of 100 mg/L. No special treatment other than a short period of mixing was necessary to completely dissolve this stock solution in test medium. The stock was clear and colourless. However, due to the extremely instable character of the test substance the solution became increasingly hazy within a short time with pH-values dropping to acidic Ieveis. The pH of the stock solutions was consequently re-adjusted to approximately 8.5 using sodium hydroxide. The hazy suspension was then filtered through a rough paper filter (Schleicher & Schuell 604) to remove the major part of undissolved test particles (> ca. 5 µm). The clear and colourless filtrate was then used for testing. The lower test concentrations for the range-finding test were prepared by subsequent dilution of the filtrate in test medium. Alltest solutions were renewed after 24 hours of exposure. Note that the time for preparation of the stock and test solutions was kept as short as possible with a maximum preparation time of approximately 30 minutes.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Source: ln-house Iabaratory culture with a known history
- Max. age at study initiation: 4 weeks
- Feeding during test: No
- Food type: suspension of fresh water algae
- Frequency: daily

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Hardness:

Water hardness: 250 mg CaCO3 / L

Test temperature:

start: 20.3 °C
During the test: 19.2 - 20.0 °C

pH:

7.8 - 8.5

Dissolved oxygen:

8.4 - 9.0

Nominal and measured concentrations:

A filtered solution prepared at a loading rate of 100 mg/L was used for the main test. The concentration Lithium present in the samples was taken as a
measure for the Lithium bis(oxalato)borate concentration present in the test solutions. Analysis of the samples taken during the Iimit test showed that measured Lithium concentrations were stable between 3.4 and 3.6 mg/L during the 24-hour refreshment periods and in agreement with what was expected based on the theoretical percentage Lithium (3.58 %) in the test substance. All results will however be based on the loading rate as measurement of Lithium can only be considered indicative for the real Lithium bis(oxalato)borate concentration present in the test solution.

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 ml, all-glass
- Fill volume: 80 ml
- Aeration: No
- Renewal rate of test solution: semi-static with renewal of test solutions after 24 hours
- No. of organisms per vessel: 5 per vessel
- No. of vessels per concentration or vehicle control (replicates): 4 (20 daphnia per concentration)
- Medium: ISO (M7)


OTHER TEST CONDITIONS
- Adjustment of pH: yes
- Photoperiod: 16 hours daily


TEST CONCENTRATIONS
- Range-finding test: 2x5 daphnia per contentration were exposed to vehicle control, a filtrate prepared at a loading of 100 mg/L and dilutions of the filtrate containing 0.1, 1.0 and 10 % of the filtrate. No immobilisation was observed during 48-hours exposure.
- Test concentrations: Therefore, in the main test a limit test with a filtrate prepared at a loading of 100 mg/L was performed.

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: A filtered solution prepared at a loading rate of 100 mg/L

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: A filtered solution prepared at a loading rate of 100 mg/L

Basis for effect:

mobility

Effect concentrations 3

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: A filtered solution prepared at a loading rate of 100 mg/L

Basis for effect:

mobility

Effect concentrations 4

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: A filtered solution prepared at a loading rate of 100 mg/L

Basis for effect:

mobility

Details on results:

No immobilisation was observed.

Any other information on results incl. tables

Read across for evaluation of short term toxicity to aquatic invertebratesof potassium bis(oxalato)borate from the toxicity study results of lithium bis(oxalato)borate is justified on the basis of structural similarity of the substances. The bis(oxalato)borate salt part [B(C2O4)2] is the same in both substances and only the cationic part of salts differ (lithium or potassium). Both lithium and potassium belong to alkali-metals.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Lithium bis(oxalato)borate did not reveal acute toxicity to Daphnia magna in a semi-static test resulting in a 48h EC50 of above 100 mg/L. The corresponding NOEC is 100 mg/L, respectively. Based on structural similarity, the result can be used for read across when evaluating acuatic toxicity of potassium bis(oxalato)borate. The study result is valid for environmental classification of both substances (LiBOB and KBOB). For risk assessment, also potassium bis(oxalato)borate can be regarded as not acutely toxic to Daphnia mgna. See also attachment in section 13 (Analogue approach justification).

Executive summary:

Lithium bis(oxalato)borate was assessed in a short term toxicity study to Daphnia magna according to OECD 202 and EU method C.2.The test substance was completely soluble in test medium at the concentrations tested. The entire project was performed applying semi-static test conditions, with renewal of test solutions after 24 hours of exposure because the test substance was known to be highly unstable in water. Test solutions were prepared starting with a stock solution at 100 mg/L. The initial test solution was clear and colourless but, almost instantaneous after dissolving the test substance in the test medium, the solution turned increasingly hazy and the pH dropped to acidic levels. The pH was adjusted to approximately 8.5 as a consequence of the observed steep pH fall.

The project started with a range-finding test exposing ten daphnia per concentration (in duplicate, 5 per vessel) to a blank-control, a test substance filtrate prepared at a loading rate of 100 mg/L and dilutions of the filtrate containing 0.1, 1.0 and 10 % of the filtrate. No immobile daphnia were observed during the 48-hour exposure period in the undiluted filtrate or any of the filtrate dilutions tested. Hence, the expected 48h EC50 exceeded the concentration present in a filtered solution prepared at a loading rate of 100 mg/L. The project was continued with a limit test exposing twenty daphnia per concentration (in quadruplicate, 5 per vessel) to a blank-control and a filtered test substance solution prepared at a loading rate of 100 mg/L.

The total test period was 48 hours. Samples for analytical confirmation of actual exposure concentrations were taken from the freshly prepared solutions at the start and after 24 hours of exposure and at the end of the test period. Analysis of the samples taken during the limit test showed that measured lithium concentrations were stable between 3.4 and 3.6 mg/L during the 24-hour refreshment periods and in agreement with what was expected based on the theoretical percentage of lithium (3.58 %) in the test substance. All results will however be based on the loading rate as measurement of lithium can only be considered indicative for the real test substance concentration present in the test solution.

The study met the acceptability criteria prescribed by the protocol and was considered valid. The test substance did not induce acute immobilisation of Daphnia magna at a loading rate of 100 mg/L after 48 hours of exposure (NOEC). The 48h EC50 exceeded a loading rate of 100 mg/L, the regulatory limit concentration. (NOTOX, 2004)

Based on structural similarity, results from the acute acuatic toxicity study can be used for read across when evaluating aquatic toxicity of potassium bis(oxalato)borate. Consequently, also potassium bis(oxalato)borate can be regarded as not acutely toxic to Daphnia magna.