Hafnium tetrachloride

Short-term toxicity to fish

Administrative data

Endpoint:

short-term toxicity to fish

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

october 2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP study, followed the recommanded guidelines (the original study was quoted with reliability 1 but the reliability 2 has to be chosen for a read across)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

yes

Remarks:

but with no effect on the study

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1075 (Freshwater and Saltwater Fish Acute Toxicity Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Hafnium dioxide

EC Number:

235-013-2

EC Name:

Hafnium dioxide

IUPAC Name:

hafnium dioxide

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

Purity (as HfO2+ ZrO2): > 99.9%
Appearance: White powder

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples for analysis were taken at the start and at the end of the test (one sample from the control and three from the test item solution), in plastic tubes, acidified with pure nitric acid (10 mL sample for 1 mL acid) and conserved at room temperature.

Test solutions

Vehicle:

no

Details on test solutions:

Because the test item is extremely poorly soluble in water, the test was carried out in a saturated solution of the test item in water.

The method was based on the elution of the test substance with the test medium from a column, which is charged with an inert support material (glass beads) mixed with an excess of the test substance. For this method aquarium water was used as eluent.

Small particles of test substance (with a relatively high surface area) were mixed with support material. This mixture was poured into the column and then filled with aquarium water. The column was connected to a re-circulating pump. The flow through the column was started 48 hours before the introduction of the fish (to achieve the constant saturated solution) and run over the test period.

Test organisms

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

Source: “Black Molly” Fish Farm, Veszprém, Hungary
Number of animals: seven fish per test group
Body length of animals: 2.8 – 3.3 cm
Food and Feeding: The fish were not fed during the test
Acclimatisation: >12 days
Animal health: Fish were bred in a well-known fish farm, under disease- and parasite-controlled conditions. Fish were observed during the acclimatisation and test periods, the fish were healthy.
One aquarium was used for test group and for the control group respectively. Both aquaria comprised 7 fish and 5 L test solution. The animals were not fed during the test. The loading of the test aquaria was 1.1 g fish/L test solution at the start of the experiment.

Study design

Test type:

flow-through

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Post exposure observation period:

There was no mortality of the population for seven days before the test.

Test conditions

Hardness:

203 mg/L (as CaCO3)

Test temperature:

between 22.4 and 23.0 °C

pH:

7.36 – 7.71

Dissolved oxygen:

in the range of 95 – 98 % of the air saturation value at the temperature used

Nominal and measured concentrations:

100 % v/v saturated solution for nominal concentration and < quantification limit for analysed measures

Details on test conditions:

The water temperature, oxygen concentration and pH were measured at the start of the test and daily thereafter.

The light-dark cycle during the test was 16 hours light and 8 hours darkness.

Because no toxic effect of the test substance was expected due to its very low solubility in the test medium, the preliminary experiment was carried out using only one test concentration at aquatic saturation and one control in order to demonstrate that the test item has no influence on test animals up to at least this test concentration (100 % v/v saturated solution). Seven fish were exposed to test concentration at aquatic saturation concentration of the test item plus a control, for 96 hours. No mortality occured during this pre test, then a limit test was conducted with 100 % v/v saturated solution only, plus a control, in the main test.

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 other: % saturated solution

Nominal / measured:

meas. (initial)

Conc. based on:

element

Basis for effect:

mortality (fish)

Effect concentrations 2

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

100 other: % saturated solution

Nominal / measured:

meas. (initial)

Conc. based on:

element

Basis for effect:

mortality (fish)

Details on results:

There were no mortality in 7 fish in the control group or in 7 fish exposed to a test concentration of 100 % v/v saturated solution.
No sub-lethal effects were observed in the control and test group for a period of 96 hours.

Reported statistics and error estimates:

No statistical analysis was performed because of the lack of toxic effects.
The LC50, NOEC, LOEC and LC100 were determined directly from the raw data.

Any other information on results incl. tables

Sublethal observations / clinical signs:

24h, 48h, 72h and 96h LC₅₀value:  >100 % v/v saturated solution (< 0.007 mg Hf/L)

96h NOEC:  100 % v/v saturated solution (< 0.007 mg Hf/L)

96h LOEC: >100 % v/v saturated solution (< 0.007 mg Hf/L)

96h LC₁₀₀value: >100 % v/v saturated solution (< 0.007 mg Hf/L)

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

- Constant conditions were maintained in this procedure - No mortality occured in the controls - The dissolved oxygen concentration (throughout the test) was at least 60 % of air saturation value

Executive summary:

The acute toxicity of Hafnium dioxide was assessed with acute toxicity test on Zebrafish (Brachydanio rerio), over an exposure period of 96 hours. One concentration at the solubility level of the test item in the test medium (100 % v/v saturated solution) plus an untreated control was tested in a limit test. All validity criteria were met during this GLP study, which is quoted with reliability 1.

Under the conditions of this study, the observed endpoints for the effect of Hafnium dioxide were the followings:

The 24h, 48h, 72h and 96h LC50 value: > 100 % v/v saturated solution (< 0.007 mg Hf/L)

The 96h NOEC: 100 % v/v saturated solution (< 0.007 mg Hf/L)

The 96h LOEC:> 100 % v/v saturated solution (< 0.007 mg Hf/L)

The 96h LC100 value: > 100 % v/v saturated solution (< 0.007 mg Hf/L)

Based on these results, Hafnium dioxide had no toxic effect at aquatic saturation solution (< 0.007 mg Hf/L) on fish; the LC50 results and the LOEC are higher than the solubility level of the test item in the test medium. These results are used in a read across approach, as explained in the aquatic toxicity summary.