Hafnium

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study, performed without any deviation

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 423 (Acute Oral toxicity - Acute Toxic Class Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Hafnium

EC Number:

231-166-4

EC Name:

Hafnium

Cas Number:

7440-58-6

Molecular formula:

Hf

IUPAC Name:

hafnium

Test material form:

other: shot

Details on test material:

Appearance: Silver grey/shot
Purity: Hf + Zr> 98% (Zr content: <1.5%)
Expiry date: 21 November 2014

Test animals

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH, Sandhofer Weg 7, D-97633 Sulzfeld
- Age at study initiation: 8-9 weeks old
- Weight at study initiation: 187 – 204 g
- Fasting period before study: The food but not water was withheld during an overnight period.
- Housing: 3 animals/ cage (Cage type: Type II polypropylene/polycarbonate)
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3 °C
- Humidity (%): 30 - 70 %
- Air changes (per hr): 15-20
- Photoperiod: Lighting period: 12 hours daily, from 6.00 a.m. to 6.00 p.m.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Remarks:

distilled water

Details on oral exposure:

VEHICLE
- Amount of vehicle (if gavage): 10 mL/kg bw

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: Initially, three female animals were treated with 2000 mg/kg bw of Hafnium because no litterature or other study could indicate a potential hazard of hafnium by ingestion. No mortality was observed, therefore further 3 animals were treated at the dose level of 2000 mg/kg bw.

Doses:

Initially, three female animals were treated with 2000 mg/kg bw of Hafnium. No mortality was observed, therefore further 3 animals were treated at the dose level of 2000 mg/kg bw.

No. of animals per sex per dose:

3 females per group

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Clinical observations were performed at 30 minutes, 1, 2, 3, 4 and 6 hours after dosing and daily for 14 days thereafter. Body weight was measured on Days -1, 0 and 7 and before necropsy.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight, macroscopic findings

Results and discussion

Effect levels

Sex:

female

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

Based on:

test mat.

Remarks on result:

other: LD50 cut off

Mortality:

Hafnium did not cause mortality at a dose level of 2000 mg/kg bw.

Clinical signs:

other: Treatment with Hafnium did not cause any test item related adverse effect during the 14 days observation period.

Gross pathology:

There was no evidence of the test item-related macroscopic observations at a dose level of 2000 mg/kg bw. Bilateral dilatation of the uterine horns, body and cervix in 1/6 female was considered to be a common background observation, and is usually associated with physiological changes during oestral cycle in females and not related to the administration of test item.

Applicant's summary and conclusion

Interpretation of results:

study cannot be used for classification

Remarks:

Migrated information

Conclusions:

Under the conditions of this study, the acute oral LD 50 value of the test item Hafnium was found to be above 2000 mg/kg bw in female CRL:(WI) rats. According the GHS criteria, Hafnium should be ranked as "Category 5" or "Unclassified".

Executive summary:

The single-dose oral toxicity of Hafnium was performed according to the acute toxic class method (OECD 423) in CRL:(WI) rats.

Two groups of three female rats were treated with Hafnium at a dose level of 2000 mg/kg bw by gavage.

Clinical observations were performed at 30 minutes, 1, 2, 3, 4 and 6 hours after dosing and daily for 14 days thereafter. Body weight was measured on Days -1, 0 and 7 and before necropsy. All animals were subjected to a necropsy and a macroscopic examination.

Hafnium did not cause mortality at a dose level of 2000 mg/kg bw, and the treatment did not cause any test item related adverse effect during the 14 days observation period. Body weight gains of Hafnium treated animals during the study showed no indication

of a treatment-related effect. There was no evidence of the test item-related macroscopic observations at a dose level of 2000 mg/kg bw.

In the conditions of this reliable study (Klimlisch 1 reliability, for a GLP study performed without any deviation), the acute oral LD 50 value of the test item Hafnium was found to be above 2000 mg/kg bw in female CRL:(WI) rats.