Tungsten dioxide

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

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

Adequacy of study:

key study

Study period:

2002-06-24 to 2002-08-20

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

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 K2. Due to similar water solubility, in vitro bioaccessibility in synthetic sweat fluid simulating dermal exposure, and available toxicity data for the target (TBO) and source (WO3) substances, the resulting toxicity potential would also be expected to be similar so read across is appropriate between these substances. In addition, read across is appropriate for this endpoint because the classification and labeling is the same for the source and target substances, the PBT/vPvB profile is the same, and the dose descriptors are, or are expected to be, sufficiently similar or more conservative for the target substance. For more details refer to the attached description of the read across approach.

Justification for type of information:

1. HYPOTHESIS FOR THE CATEGORY APPROACH: The hypothesis is that properties are likely to be similar or follow a similar pattern because of the presence of a common metal ion, in this case tungstate.
2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES):
Source: Tungsten trioxide
Target: Tungsten Dioxide
3. CATEGORY APPROACH JUSTIFICATION: See Annex 3 in CSR
4. DATA MATRIX: See Annex 3 in CSR

Cross-reference

Reason / purpose for cross-reference:

read-across: supporting information

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 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)

GLP compliance:

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
- Molecular formula: WO3
- Supplier: Sponsor
- 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: < 10 mg/L WO3

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Wiga, D-97633
- Weight at study initiation: 1.8-2.0 kg
- Housing: Animals were housed singly in metal wire cages, type KK 016R
- Diet: Altromin 2023 diet for rabbits - ad libitum. Hay briquettes were offered additionally as a dietary supplement.
- Water: Tap water from an automatic watering system - ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): Average of 19.6 °C
- Humidity (%): Average of 70.3%
- Air changes (per hr): 12/hr
- Photoperiod (hrs dark / hrs light): 12 dark/12 light (6 am to 6 pm)

IN-LIFE DATES: From: 2004-06-24 To: 2004-06-28

Test system

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

other: deionised water

Controls:

other: surrounding untreated skin

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 g/ 2.5 cm X 2.5 cm patch

VEHICLE
- Amount(s) applied (volume or weight with unit): 1.0 mL

Duration of treatment / exposure:

4 hours

Observation period:

72 hours

Number of animals:

3 females

Details on study design:

TEST SITE
- Area of exposure: 2.5 cm X 2.5 cm on the clipped dorsal areas of the trunk of the rabbits.
- Type of wrap if used: cellulose patches and self adhesive non woven, hypoallergenic fabric

REMOVAL OF TEST SUBSTANCE
- Washing (if done): Residual test substance was wiped off with wet Kleenex tissues after 4 hour exposure period, if necessary.

SCORING SYSTEM: Erythema/Eschar and Oedema

- The skin was examined using a cold light source KL 1500 electronic

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Results 2

Irritation parameter:

edema score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

All areas to be treated with the test substance and all control areas were normal before the application and at each observation time.

Other effects:

No general toxic effects were noted.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

All areas to be treated with the test substance and all control areas were normal before the application and at each observation time. The mean scores for three of the animals at 24, 48 and 72 hrs. post application were 0.0 when observing for Erythema/Eschar and Oedema.

Executive summary:

No skin irritation data of sufficient quality are available for tungsten dioxide (target substance).  However, skin irritation data are available for tungsten trioxide (source substance), which will be used for read-across. Due to similar water solubility, in vitro bioaccessibility in synthetic alveolar, lysosomal, and interstitial fluids simulating inhalation exposure, and available toxicity data for the target and source substances, the resulting toxicity potential would also be expected to be similar, so read-across is appropriate between these substances. In addition, read-across is appropriate for this endpoint because the classification and labeling is the same for the source and target substances, the PBT/vPvB profile is the same, and the dose descriptors are, or are expected to be, sufficiently similar. For more details, refer to the read-across category approach included in the Category section of this IUCLID submission and/or as Annex 3 in the CSR.