Hafnium tetrachloride

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

key study

Study period:

2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP study performed without any deviation to the guideline, but quoted with reliability 2 because of the read across

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

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
Expiry date: 21 November 2012

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples for analysis were taken at the beginning and at the end of each renewal period. Five samples were taken at the beginning of the first renewal period and four samples were taken at the beginning of the second renewal period both from the control and test item solution. At the end of the renewal periods 2 samples were taken from each replicate (sum of 8 samples per group) both from the control and test item solution.
Samples (filtrated and acidified (10 ml sample + 1 ml HNO3)) were taken in plastic tubes, acidified with pure nitric acid in agreement with the requirements of the PI.

Test solutions

Vehicle:

no

Details on test solutions:

Because the test item is insoluble in water the test solution was prepared using WAF method. A supersaturated test item solution (nominally 100 mg/L) was prepared by dispersing/dissolving the amount of test item into the test medium (ISO Medium) two days before the start of the experiment. This solution was shaken for about 24 hours at approximately 30°C and then equilibrated for about 24 hours at the test temperature. The non-dissolved test material was removed by filtration through a fine (0.22 µm) filter to give the 100 % v/v saturated solution.
The test was performed under semi-static conditions. The frequency of the water renewal periods was 24 hours.
Prior to treatment of each renewal periods, the test item stock solution and appropriate diluting of the stock solution were prepared by the method described above.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Source: National Institute of Public Health 1097 Budapest Gyáli u. 2-6. Hungary
- Age at study initiation (mean and range, SD): They were less than 24 h old at the beginning of the test
- Feeding during test: The animals were not fed during the test.

ACCLIMATION: There was no acclimatization because the water used was similar to the culture water

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Hardness:

approximate theoretical total hardness of 249 mg/L (as CaCO3)

Test temperature:

The test temperature was in the range of 20.4 – 21.0°C measured in the test vessels. The additionally measured temperature in the climate chamber was between 20.2 and 20.6°C.

pH:

7.90 – 8.01

Dissolved oxygen:

7.0 – 7.3 mg/L

Nominal and measured concentrations:

Only one test concentration (100 % v/v saturated solution) at the solubility level of the test item in the test medium and one control group were tested in a limit test.

Details on test conditions:

TEST SYSTEM
- Test vessel: glass beaker
- Material, size, headspace, fill volume: at least 5 mL test solution/animal
- Renewal rate of test solution: each 24h
- No. of organisms per vessel: There were 20 animals in test group and control group respectively, divided into 4 replicates (5 animals/ replicate)

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16-hour light and 8-hour dark cycle.

EFFECT PARAMETERS MEASURED:
The immobility or mortality of the Daphnia was determined by visual observation 24 and 48 hours after the start of the test. Those animals not able to swim within 15 seconds after gentle agitation of the test beaker are considered to be immobile.
The number of immobilised animals and the percentage of immobility were determined at 24 and 48 hours.
The water temperature, oxygen concentrations and pH of the controls and the test solutions were measured at the beginning and at the end of each renewal period.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 other: % saturated solution

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 other: % saturated solution

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

There was no immobilisation in 20 daphnids exposed to each group. In addition to immobility, no abnormal behaviour or appearance of test animals was detected.

Any other information on results incl. tables

There were no immobilized animal in the control group andthe dissolved oxygen concentration at the end of the test in control and test vessels was more than 3 mg/L.All validity criteria were within acceptable limits and therefore the study can be considered as valid.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

There were no immobilized animal in the control group and the dissolved oxygen concentration at the end of the test in control and test vessels was more than 3 mg/L.

Executive summary:

Acute toxicity ofHafnium dioxidewas assessed with Acute immobilisation test on Daphnia magna, over an exposure period of 48 hours in a semi-static system. One concentration at the solubility limit 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 study, which is considered as reliable.

Under the conditions of this Daphnia magna acute immobilisation study the observed endpoints for the effect of Hafnium dioxide were the followings:

The 24h and 48h, EC₅₀value:   >100 % v/v saturated solution (< 0.007mg Hf/L)

The 48h NOEC:                            100 % v/v saturated solution (< 0.007mg Hf/L)

The 48h LOEC:                          >100 % v/v saturated solution (< 0.007mg Hf/L)

The 48h EC₁₀₀value:                  >100 % v/v saturated solution (< 0.007mg Hf/L)

Based on the results of this study, the test itemHafnium dioxidehadno toxic effect at saturation(< 0.007mg Hf/L) on Daphnia; the EC₅₀results and the LOEC are higher than the solubility level of the test item in the test medium.