Zirconium oxide, hafnium and ytterbium doped

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:

2016-05-18 to 2016-09-27

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:

13 April 2004

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: H.C. Starck, 7160103
- Expiration date of the lot/batch: 18.04.2018

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Store container tightly closed in dry place at room temperature
- Stability under test conditions: stable under storage conditions
- Solubility and stability of the test substance in the solvent/vehicle: Slightly soluble in water
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: none

Analytical monitoring:

yes

Details on sampling:

The analyses were performed without GLP at ASG Analytik-Service Gesellschaft mbH according to the test method DIN EN ISO 17294-2 and ASG 2002-ICP-MS.
- Concentrations: Nominal concentrations 0, 100 mg/L
- Sampling method: Two additional vessels without test organisms were prepared for the accompanying chemical analysis. Samples were taken in duplicate from test dilution and the control at 0 h, 24h and 48 h from separate test vessels without daphnids.
- Sample storage conditions before analysis: They were kept in the refrigerator at 5 ± 3 °C until being sent to the analytical laboratory. A retain sample was kept in the freezer at < -18 °C until finalization of the study.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A water accommodated fraction (WAF) with a loading rate of 100 mg/L was prepared with M4 medium according to OECD 202. The WAF was prepared by adding 50.3 mg of the test item to 500 mL of M4 medium. The test item was weighed of an inert PE-foil and then transferred together into the M4 medium. Another vessel with 500 mL M4 medium and an inert PE-foil but without test substance was treated the same way (negative control). The WAF was shaken for 24 h in the dark at 21.8 – 22.2 °C. For shaking an overhead shaker was used (about 15 rpm). After skaking was stopped, undissolved material was allowed to sediment or float for a period of about 75 minutes. After this sedimentation period, the WAF was clear. The test solutions were withdrawn from the middle of the suspension in the beakers using a glass tube and transferred into the test vessels.
- Differential loading: single loading rate of 100 mg/L
- Controls: yes
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): undissolved material was allowed to sediment or float for a period of about 75 minutes. After this sedimentation period, the WAF was clear.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna Straus
- Strain/clone: from the clone breeding of the Federal Environment Agency, department IV 2.4, Berlin
- Justification for species other than prescribed by test guideline:
- Source: cultivated at Hydrotox GmbH since October 2012
- Feeding during test: no
- Food type: Desmodesmus subspicatus algae
- Amount: approx. 0.1 mg C × daphnid-1 × day-1
- Frequency: on workdays

ACCLIMATION
Culturing conditions same as test: cultured at 20 ± 2 °C with 16 h light : 8 h dark in M4 medium

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test temperature:

19.3 – 21.1 °C

pH:

7.2 - 7.5 in the control and 7.5 - 7.7 in the test item treatment.

Dissolved oxygen:

7.4 - 7.6 mg/L in the control and 7.4 - 7.7 mg/L in the test item treatment

Nominal and measured concentrations:

Nominal loading rate in the test vessel [mg/L]: 0, 100
Accompanying chemical analysis revealed that the solubility of elemental zirconium and ytterbium of the test item is below the limit of quantification (< 1 μg/L).
Measurements of all samples of zirconium and ytterbium were below the limit of quantification (< 1 μg/L). No detection of dissolved zirconium and ytterbium could be measured in 100 mg/L of the test samples.
The reference standard sample of ytterbium of 1 mg/L was detected with 0.830 mg/L and within the accepted range of +/- 20 %.
The reference standard samples of zirconium of 1 mg/L was detect with 0.720 mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers 50 mL, Schott, Mainz
- Aeration: no
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates): not applicable

TEST MEDIUM / WATER PARAMETERS
The test medium used was M4 medium according to OECD 202.
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 h light: 8 h dark for 48 h

EFFECT PARAMETERS MEASURED (with observation intervals if applicable):
- Determination of immobilization after 24 and 48 h. The swimming capability of the daphnids was determined after 24 h and 48 h exposure. Animals that did not swim within 15 s after gently moving were considered to be immobile.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

24 h

Dose descriptor:

LOELR

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOELR

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

NOELR

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOELR

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: not reported
- Other biological observations: no
- Mortality of control: 5 % Immobility (1 Daphnia) of control after 48 h
- Effect concentrations exceeding solubility of substance in test medium: no

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EC50 (24h) = 1.30 mg/L (95%-confidence interval: 1.07 - 1.43 mg/L)
- EC50 (48h) < 1.25 mg/L
The EC50-value of the reference item potassium dichromate is in the declared range of 0.6 - 2.1 mg/L (24 h) according to OECD 202.

Reported statistics and error estimates:

The effect occurrence after 24 h and 48 h exposure was calculated. With the statistical software ToxRat Professional 2.10.05 (ToxRat Solutions GmbH, Alsdorf, Germany), LOEC/NOEC were determined as far as mathematically possible.

Criteria of validity

• Immobilisation of the test organisms in the control (5 %) at the end of the test was ≤ 10 %.

• Dissolved oxygen concentration at the end of the test in the control and the test item treatment (≥ 7.4 mg/L) at the end of the test was ≥ 3 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

The Daphnia magna acute immobilisation test according to OECD 202 was performed using a single loading rate of 100 mg/L. Following results were obtained:
- LOELR (48h) > 100 mg/L
- NOELR (48h) >= 100 mg/L
Accompanying chemical analysis revealed that the solubility of elemental Zirconium and Ytterbium of the test item is below the limit of quantification (< 1 μg/L).

Executive summary:

The 48-hr acute immobilisation test of the test item to Daphnia magna was conducted under static conditions. Daphnids were exposed to a control containing no test substance, and ytterbium zirconium oxide at a nominal single loading rate of 100 mg/L for 48 hr. Immobilisation was observed daily. The 48-hour LOELR was > 100 mg/L (nominal test item loading rate).

The 48-hour NOELR was >= 100 mg/L (nominal test item loading rate).

This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

 

Results Synopsis

 

Test Organism Age: 0.25 - 24 h

Test Type: static

 

- 48 hr LOELR: > 100 mg/L (nominal)

- 48 hr NOELR: >= 100 mg/L (nominal)

Endpoint(s) Effected:  Immobility

 

Description of key information

The 48-hr NOEL of the test item to Daphnia magna is ≥ 100 mg/L (nominal loading).

Accompanying chemical analysis revealed that the solubility of elemental zirconium and ytterbium released from the test item is below the limit of quantification (< 1 μg/L).