Magnesium fluoride

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:

31 January 2017- 3 February 2017

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:

resp. EU C.2

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Materion / lot 662599-1
- Expiration date of the lot/batch: 31-Jul 2017
- Purity test date: 18- Jan-2016

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: RT, away from moisture
- Stability under test conditions: stable
- Solubility and stability of the test substance in the solvent/vehicle: low solubility
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: not expected

Analytical monitoring:

yes

Details on sampling:

Samples were WAFs. This was done by weighing the nominal load 100 mg/L (real load 100.1 mg/L), adding tap water and stirring for 24 hours. The resulting solution was filtrated through 0.45 µm Nylon filters. Sampling intervals were 0, 24h and 48h.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

20 hours before the start of the test, the adult animals were separated from the young. 0.5 hours before test start, the adults were caught with the help of a glass tube, and the new-born Daphnia, aged between 0 and 19 hours, were sieved from the medium and immedi-ately placed into a 250 mL-beaker containing dilution water. After a settling-in period of 30 minutes, animals which showed no apparent damage were used for the test.
Switching from M4-medium (husbandry) to Dilution water (test) has been shown not to cause any detrimental effects for test Daphnia.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea, Daphnia magna
- Strain/clone: Berlin
- Source: Umweltbundesamt Berlin
- Age of parental stock: between 0 and 24 hours
- Feeding during test: No feeding during the tests.
- Food type: unicellular green algae (Desmodesmus subspicatus)

ACCLIMATION
- Acclimation period: Daphnia magna is bred in the LAUS GmbH throughout the year. The animals are kept for the use in toxicity tests. They multiply by parthenogenesis, thus being genetically identi-cal. The husbandry is performed similar to the method described in the OECD guideline, following SOP 115 002 01 („Zucht und Hälterung von Daphnia magna STRAUS“)
- Medium: M4-Medium (recipe of ELENDT)
- Type and amount of food: unicellular green algae (Desmodesmus subspicatus)
- Vessels: preserving glasses, nominal volume 2 L
- Health during acclimation: mortality was not observed

Test type:

static

Water media type:

freshwater

Remarks:

Deionised water with an enrichment of certain minerals (dilution water as demanded in the guidelines)

Limit test:

yes

Total exposure duration:

48 h

Test temperature:

19.0 – 20.1 °C

pH:

7.7-7-8

Dissolved oxygen:

8.8-9.5

Nominal and measured concentrations:

blank control and nominal concenration of 100 mg/L (real load 100.1 mg/L)

Details on test conditions:

TEST SYSTEM
- Test vessel: Beakers
- Type: Closed
- Material, size, headspace, fill volume: glass, nominal volume 50 mL
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4 vessels, each containing 20 mL test solution and 5 Daphnia
- No. of vessels per control (replicates): 4 vessels, each containing 20 mL test solution and 5 Daphnia

TEST MEDIUM / WATER PARAMETERS
-CaCl2*2H2O: 293.80 mg/L
-MgSO4*7H2O: 123.30 mg/L
-NaHCO3:64.80 mg/L
-KCl: 5.80 mg/L
-Resulting hardness in mmol/L:2.502 mg/L
-Resulting hardness in mg CaCO3/L: 250 mg/L

- Dissolved oxygen and pH: Dissolved oxygen and pH were measured in the batch solutions prepared for each control and treatment group at the beginning of the test and at the 24-hour, and in each test chamber at the end of each 24-hour period. Dissolved oxygen was measured using a Thermo Model 340i wtw dissolved oxygen meter, and measurements of pH were made using a pH meter 340i wtw.

OTHER TEST CONDITIONS
- Photoperiod: 16 hours of light and 8 hours of darkness, using neon tubes

RANGE-FINDING STUDY
- Test concentrations: Blank control and 100 mg/l (Limit test)

Reference substance (positive control):

yes

Remarks:

Potassium dichromate K2Cr2O7 (CAS No. 7778-50-9)

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mortality

Details on results:

- Mortality of control: none of the Daphnia were immobilised
- Other adverse effects control: Switching from M4-medium (husbandry) to Dilution water (test) has been shown not to cause any detrimental effects for test Daphnia

See section "Any other information on results incl. tables" for details on results (table 4, table 5, and table 6)

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Potassium dichromate K2Cr2O7 (CAS No. 7778-50-9)
- EC50: 1.7 mg/L (range of 0.6 – 2.1 mg/L)

Table 4. Immobility
Nominal Concentration in mg/L	Immobility 24 hours					Immobility 48 hours
	absolute				in %	absolute				in %
Blank control	0	0	0	0	0	0	0	0	0	0

Table 5. pH and O2-values
Nominal Concentration in mg/L	pH		O2-Concentration in mg/L
	0 h	48 h	0 h	48 h
Blank control	7.8	7.7	9.5	8.9
100	7.8	7.8	9.5	8.8

Table 6. Biological Results Test Item
Parameter	Value
24h EC50	> 100 mg/L
48h EC50	> 100 mg/L
48h NOEC	≥ 100 mg/L
48h LOEC	> 100 mg/L

Validity criteria fulfilled:

yes

Remarks:

-Immobilisation in the blank controls was 0 %. -The lowest concentration of dissolved oxygen at the end of the test was 8.8 mg/L.- There was no variation of pH during the test.

Conclusions:

The 48-hour toxicity of water flea (Daphnia magna) to Magnesium Fluoride was determined according to OECD 202 guideline in compliance with GLP. The study was conducted as a limit test and it was based on nominal concentration of 100 mg/l. As a result, EC 50 was determined.

Executive summary:

The 48-h acute toxicity to water flea (Daphnia magna) was determined by using a static test design. The test followed EU-Method C.2. resp. OECD Guideline 202 and it was perfomed as a limit test using the nominal concentration 100 mg/L.None of the animals were immobilised in the treatment and in the blank control.

At the start and at the end of the test, the content of Magnesium in the test solutions was determined using ICP-OES. Only in the test solution at the end of the test a very low concentration of Magnesium was detectable. All other measured values are below the LOD. Therefore, the determination of the biological results was based on the nominal concentration. Potassium dichromate K₂Cr₂O₇(CAS No. 7778-50-9) was used as positive control to assure that the test conditions are reliable.

 

No observations were made which might cause doubts concerning the validity of the study outcome. All validity criteria were met.

Description of key information

The acute test (OECD 202) of water flea (Daphnia magna) to Magnesium fluoride was determined using static test system and it was performed as a limit test using a nominal concentration of 100 mg/l. . The study was conducted according to OECD 202 and followed OECD Principles of Good Laboratory Practice (GLP). No unusual observations or deviations from standard test protocol were noted.

As a result, 48-h EC50 was calculated as >100 mg/L.

Based on the available data, the 48-h EC50-value was selected as a key value.

The data obtained from testing on freshwater species has been used as basis for assessment of effects in marine environment as well as for extrapolation of the measured effects to other compartments within the aquatic ecosystem (e.g. sediment) and soil.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Marine water invertebrates

Marine water invertebrates

Effect concentration:

100 mg/L

Additional information

The short-term toxicity to aquatic invertebrates results obtained from the supporting read-across substance (sodium fluoride) has been provided.