Dilithium peroxide

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:

06 SEP 2021 - 05 OCT 2021

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:

adopted 13th April 2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

Dated May 30, 2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Version / remarks:

October 2016

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

ISO Medium

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 0.0060 g of test item was suspended in 600 mL of the dilution water in order to give the nominal loading rate of 10 mg/L of the test item. The further test item concentrations were prepared from this test item stock solution (TISS)
- Controls: untreated control, reference control
- Concentration of vehicle in test medium (stock solution and final test solution(s) or suspension(s) including control(s)): Reconstituted water (ISO Medium, according to OECD 202) was used as dilution water in the experiment. Separate stock solutions of individual substances were first prepared in deionised water (prepared in TOXI-COOP ZRT. by ELIX 3 Int. water purification system, Serial No.: F0MA71964D). The ISO Medium was prepared by adding 25 mL from each of four stock solutions up to one litre deionised water proportionally.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea (Daphnia)
- Strain/clone: Daphnia magna (Straus)
- Age at study initiation (mean and range, SD): Less than 24 h old at the start of exposure period
- Source: Laboratory of Hydrobiology (Central Agricultural Office, Directorate of Plant-, and Soil Protection) 2100 Gödöllő, Kotlán S. u. 3. Hungary
- Feeding during test : The Daphnia were fed with concentrated algal suspension of Raphidocelis subcapitata during the holding. Test animals were not fed during the exposure.

ACCLIMATION
Test animals were bred under similar (or the same) conditions as that used during the exposure period (holding water, temperature, background colour etc.), therefore additional acclimatisation before the test was not necessary. Brood daphnids were maintained in dilution water at the test temperature for at least 48 hours prior to the start of the test.

Test type:

static

Water media type:

other: Reconstituted water (ISO Medium, according to OECD 202)

Limit test:

no

Total exposure duration:

48 h

Hardness:

245.6 mg/L (as CaCO3)

Test temperature:

21.3 – 21.4 °C

pH:

7.62 - 8.20

Dissolved oxygen:

7.91 – 8.52 mg/L

Nominal and measured concentrations:

- Concentrations: 0.625, 1.25, 2.5, 5 and 10 mg/L nominal

Details on test conditions:

TEST SYSTEM
- Test vessel: glass beaker; volume app. 50 mL
- Volume of solution: approximately 40 mL of test solution
- Aeration: no
- No. of organisms per vessel: 5
Twenty animals in every groups (test concentrations and untreated control), divided into 4 replicates (5 animals per replicates).

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted water (ISO Medium, according to OECD 202) was used as dilution water

OTHER TEST CONDITIONS
- Adjustment of pH: the pH of the test item stock solution (10 mg/L test concentration) was adjusted to that of the dilution water (7.76) by using 1 N HCl-solution
- Photoperiod: 16 hours light (artificial illumination) and 8 hours darkness.
- Light intensity: 1092 lux at the start of the test.

VEHICLE CONTROL PERFORMED: yes, the dilution water (ISO Medium, see section 5.4) without test item added was used as untreated control solution.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

7.05 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks:

100 % immobility was detected

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

6.54 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Immobilisation and behavioural abnormalities: No immobilisation was observed in the concentration range of 0.625 – 5 mg/L. In addition to immobility, no abnormal behaviour or appearance of test animals was detected in these test groups. At the highest test concentration of 10 mg/L 100 % immobility was detected.
- Other biological observations: no
- Mortality of control: no
- Other adverse effects control: no
- Immobilisation of control: No immobilisation observed.

Analytical results:
- The concentrations of the test item were analysed at the start and at the end of the experiment. Test item was determined based on the measured lithium concentration. Signal intensities measured for the untreated control samples were below the quantification limit (i.e. no interfering component was detected in the untreated control samples).
Measured concentrations of the test item were in the range of 94 – 114% of the nominal concentrations. Therefore, the biological results are based on the nominal test item concentrations.

Results with reference substance (positive control):

For the evaluation of the quality of the Daphnia clone and the experimental conditions, Potassium dichromate is tested at least twice a year to demonstrate satisfactory test conditions. The date of the last study (Study Code: 392-202-5970) with reference item Potassium dichromate was: 30 – 31 March 2021.

The 24h EC50 value was determined to be 0.94 mg/L (95% conf. limits: not determined).

Name: Potassium dichromate (K2Cr2O7)
Batch No.: K50498364
Description: Orange crystalline
Expiry Date: 31 July 2023
Storage: Room temperature
Supplier: MERCK KGaA

Validity criteria fulfilled:

yes

Conclusions:

In this 48-hour acute toxicity test on Daphnia magna, the obtained results showed that the test item Lithium Peroxide Pure Grade had significant toxic effects on the mobility of Daphnia.
The 48-h EC50 value was determined to be 7.05 mg/L.
The 48 -h EC10 value was determined to be 6.54 mg/L.
The 48-h NOEC was determined to be 5 mg/L.
The 48-h LOEC was determined to be 10 mg/L.
All validity criteria were met. The results are based on nominal test item concentrations.

Executive summary:

The test was performed according to the OECD Guideline 202, EU Method C.2 and EPA Guidelines, OCSPP 850.1010 under GLP compliance. Young Daphnia were exposed to the nominal test item concentrations of 0.625, 1.25, 2.5, 5 and 10 mg/L in aqueous test media for 48 hours under defined and static conditions. In this 48-hour acute toxicity test on Daphnia magna, the obtained results showed that the test item Lithium Peroxide Pure Grade had significant toxic effects on the mobility of Daphnia.

The 48-h EC50 value was determined to be 7.05 mg/L.

The 48-h NOEC was determined to be 5 mg/L.

The 48 -h EC10 value was determined to be 6.54 mg/L.

The 48-h LOEC was determined to be 10 mg/L.

All validity criteria were met. The results are based on nominal test item concentrations.

Description of key information

The acute immobilisation of the test item to Daphnia magna was determined according to OECD Guideline 202. The EC50 value after 48 h was determined to be 7.05 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

7.05 mg/L

Additional information

The test was performed according to the OECD Guideline 202, EU Method C.2 and EPA Guidelines, OCSPP 850.1010 under GLP compliance. Young Daphnia were exposed to the nominal test item concentrations of 0.625, 1.25, 2.5, 5 and 10 mg/L in aqueous test media for 48 hours under defined and static conditions. In this 48-hour acute toxicity test on Daphnia magna, the obtained results showed that the test item Lithium Peroxide Pure Grade had significant toxic effects on the mobility of Daphnia.

The 48-h EC50 value was determined to be 7.05 mg/L.

The 48-h NOEC was determined to be 5 mg/L.

The 48 -h EC10 value was determined to be 6.54 mg/L.

The 48-h LOEC was determined to be 10 mg/L.

All validity criteria were met. The results are based on nominal test item concentrations.