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Toxicological information

Acute Toxicity: oral

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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:
1998-02-24 to 1999-06-24
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
Well documented, scientifically sound study that followed OECD Guideline 401 and GLP.
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 Carbide
Target: Fused tungsten carbide
3. CATEGORY APPROACH JUSTIFICATION: See Annex 3 in CSR
4. DATA MATRIX: See Annex 3 in CSR
Cross-reference
Reason / purpose:
read-across: supporting information

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
1999
Report Date:
1999
Reference Type:
publication
Title:
SIDS Initial Assessment Report for SIAM 21 for Tungsten Carbide (12070-12-1), Washington DC,18-20 October, 2005
Author:
OECD-SIDS
Year:
2005
Bibliographic source:
UNEP Publications
Report Date:
2005

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 401 (Acute Oral Toxicity)
Deviations:
yes
Remarks:
The lowest humidity recorded was 29%. This was lower than the range of 30 - 70% stated in the protocol. This deviation was not considered to have affected the integrity or validity of the study.
GLP compliance:
yes
Test type:
standard acute method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Test substance: tungsten carbide, WC HC 240- Purity: 99.98%- Physical state: Grey powder- Storage condition of test material: Room temperature- Expiration date of the lot/batch: Not advised

Test animals

Species:
rat
Strain:
other: Hsd: Sprague-Dawley(CD))
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Obtained from Harlan U.K. Ltd, Bicester, Oxon, England.
- Age at study initiation: four to seven weeks or age.
- Weight at study initiation: range of 80 to 101 g.
- Fasting period before study: Access to food only was prevented overnight prior to and for approximately 4 hours after dosing.
- Housing: Rats were allocated without conscious bias to cages within the treatment group and housed in groups of five rats of the same sex in metal cages with wire mesh floors.
- Diet (e.g. ad libitum): A standard laboratory rodent diet (Special Diet Services RM1(E) SQC expanded pellet)
- Water: drinking water provided ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 21 to 22.5 degree C
- Humidity: 9-52%
- Air changes: Air exchange was maintained at 10 to 15 air changes per hour.
- Photoperiod: lighting controlled by means of a time switch to provide 12 hours of artificial light (0700 - 1900 hours).


IN-LIFE DATES: From: 1998-02-24 To: 1998-03-10

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
other: 1 % w/v aqueous methylcellulose
Details on oral exposure:
The test substance was formulated at a concentration of 20 % (w/v) in 1 % (w/v) aqueous methylcellulos which was administered at a volume of 10 mL/kg-bw.
Doses:
single oral gavage dose of 2000 mg/kg bw
No. of animals per sex per dose:
5 male and 5 females
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
Statistics:
no data

Results and discussion

Effect levelsopen allclose all
Sex:
male/female
Dose descriptor:
LD50
Effect level:
> 2 000 mg/kg bw
Sex:
male/female
Dose descriptor:
other: NOEL
Effect level:
> 2 000 mg/kg bw
Mortality:
0/5 for males and females
Clinical signs:
Piloerection was observed in all rats within three minutes of dosing. This sign persisted and was accompanied on Day 2 only by ungroomed appearance (characterised by ungroomed coat) in all males. There were no other signs of reaction to treatment and recovery was complete in all animals by Day 3.
Body weight:
No changes in body weight gain were seen.
Gross pathology:
No macroscopic abnormalities at terminal kill on day 15 were observed.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The acute lethal oral dose to rats of Tungsten Carbide Powder - Pure was demonstrated to be greater than 2000 mg/kg bodyweight.
Executive summary:

No oral acute toxicity data of sufficient quality are available for fused tungsten carbide (target substance). However, oral acute toxicity data are available for tungsten carbide (source substance), which will be used for read-across. Due to similar water solubility and lower toxicity for the target substance compared to the source substance, the resulting read-across from the source substance to the target substance is appropriate. In addition, read-across is appropriate because the classification and labelling is similar for the source substance than the target substance, the PBT/vPvB profile is the same, and the dose descriptors are, or are expected to be, lower for the source substance. For more details, refer to the read-across category approach included in the Category section of this IUCLID submission and/or as an Annex in the CSR.