Dihydrogen wolframate

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Study period:

2002-07-02 to 2002-08-20

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Well documented, scientifically sound study that was conducted in accordance with GLP and OECD Guideline 423, limit test. The reliability of this study for the substance tested is a K1, but in application of read-across to a different substance, ECHA's guidance specifies that the score can be a maximum of a K2.

Justification for type of information:

Tungstic acid (WO3•H2O) is the hydrated form of tungsten trioxide (WO3). Based on Annex V, hydrates and water free forms (anhydrous) of compounds can be regarded as the same substance for registration purposes. Therefore, tungstic acid will be considered equivalent to WO3. For more details on the rationale, refer to the attached description of the read-across approach (see Annex 3).

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Tungsten trioxide

EC Number:

215-231-4

EC Name:

Tungsten trioxide

Cas Number:

1314-35-8

Molecular formula:

O3W

IUPAC Name:

trioxotungsten

Details on test material:

- Name of test material (as cited in study report): Tungsten oxide (WO3)
- Physical state: Yellow to greenish powder
- Analytical purity: 99.88%
- Purity test date: 2002-05-28
- Stability under test conditions: 5 years
- Storage condition of test material: Ambient temperature, dry
- Melting Point: Approx. 1473 degrees C
- pH: 6.1 (aqueous suspension, 100 g/L)
- Solubility in water: <10 mg/L WO3

Test animals

Species:

rat

Strain:

other: Crl:CD(SD)IGS BR

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River WIGA
- Age at study initiation: Approximately 8 weeks
- Weight at study initiation: 166-167 g (females), 195-201 (males)
- Fasting period before study: Yes; the feed was withdrawn the evening before the administration of the test substance and was offered again about three hours afterwards.
- Housing: Single caging in Makrolon cages type III (39 cm x 23 cm bottom area, 18 cm height). Wire mesh lids. Sanitation of cages once a week.
- Diet: Altromin 1324 forte, gamma irradiated with 25 kGy60Co, ad libitum.
- Water: Tap water from an automatic watering system, ad libitum.
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): average of 22.2 ⁰C
- Humidity (%): Average of 64.7%
- Air changes (per hr): 12/hr
- Photoperiod (hrs dark / hrs light): 12 dark/12 light (6 am to 6 pm)

IN-LIFE DATES: From: 2002-07-02 To: 2002-07-17

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

DOSE VOLUME APPLIED: 10 mL /kg body weight

DOSAGE PREPARATION: Doses of 2000 mg/kg body weight were prepared as suspensions in deionised water. Suspensions were prepared freshly before administration and were administered within 5 minutes after the preparation.

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: As requested by the sponsor

Doses:

2000 mg/kg body weight (in two steps)

No. of animals per sex per dose:

3 males and 3 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
- Clinical observations- 0-0.5, 0.5-1, 1-2, 2-4, and 4-6 hours after administration and then at least once a day for a total of 2 weeks. Observations included but were not limited to changes in skin, fur, eyes, the occurrence of secretions and excretions, autonomic activity, changes in gait, posture and the presence of convulsions.
- Body weights- before administration, day 7, and day 14 post administration. Bodyweight gain was calculated for each week of the study, ie between 0 and 7 days post administration and 7 and 14 days post administration.
- Necropsy of survivors performed: Yes

Statistics:

no data

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Mortality:

None

Clinical signs:

other: All animals were normal during the whole observation period.

Gross pathology:

All animals were normal at the necropsy, 14 days post administration.

Other findings:

There was no significant sex difference in the response to the test substance at 2000 mg/kg body weight.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

No toxic effects of the test substance were noted by signs in life and post mortem. No mortality occurred. An LD50 of > 2000 mg/kg body weight for rats was established for the test substance.

Executive summary:

No oral acute toxicity data are available for tungstic acid (target substance). However,oral acute toxicity data are available for tungsten trioxide (source substance), which were used for read-across. Tungstic acid (WO3•H2O) is the hydrated form of tungsten trioxide (WO3). Based on Annex V, hydrates and water free forms (anhydrous) of compounds can be regarded as the same substance for registration purposes. Therefore, tungstic acid will be considered equivalent to WO3. For more details on the rationale, refer to the attached description of the read-across approach.