Registration Dossier

Diss Factsheets

Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2002-02-07,2002-02-18
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2002
Report date:
2002

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
GLP compliance:
no
Test type:
traditional method
Limit test:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
Tungsten
EC Number:
231-143-9
EC Name:
Tungsten
Cas Number:
7440-33-7
Molecular formula:
W
IUPAC Name:
tungsten
Constituent 2
Reference substance name:
Sulfur
EC Number:
231-722-6
EC Name:
Sulfur
Cas Number:
7704-34-9
Molecular formula:
S
IUPAC Name:
sulfur
Test material form:
solid: particulate/powder
Details on test material:
- Particle size distribution: D50= 3.1 um; D90=6.5 um
- Mass median aerodynamic diameter (MMAD):
- Density: 7.69 g/cm3
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: batch no.16031/01
- Expiration date of the lot/batch:2002-04-01
- Purity test date: >98%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature in a dark dry place
- Stability under test conditions: Stable

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: particle size distribution
- Final preparation of a solid: test material was ground with a blender

FORM AS APPLIED IN THE TEST (if different from that of starting material): test material was grounded

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River Wiga GmbH, Sulzfeld, Germany
- Females (if applicable) nulliparous and non-pregnant: [yes/no]: yes
- Age at study initiation: 5-6 weeks
- Weight at study initiation: mean body weight of 305 g and 192 g for male and female animals, respectively
- Housing:suspended stainless steel cages fitted with wire-mesh floor and front
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 41 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): between 20.0 and 24.3 °C
- Humidity (%): 70% relative humidity
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12-hour light and 12-hour dark cycle

IN-LIFE DATES: From: To:2001-08-17,2002-02-18

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
nose/head only
Vehicle:
air
Mass median aerodynamic diameter (MMAD):
ca. 3 µm
Geometric standard deviation (GSD):
ca. 1.9
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: nose-only inhalation chamber
- Exposure chamber volume: ca.50
- Method of holding animals in test chamber:secured in plastic animal holders (Battelle), positioned radially through the outer cylinder around the central column
- Source and rate of air: air controlled by a pressure reducing valve at 0.76 bar
- Method of conditioning air:
- System of generating particulates/aerosols:
- Method of particle size determination:
- Treatment of exhaust air:
- Temperature, humidity, pressure in air chamber:

TEST ATMOSPHERE
- Brief description of analytical method used:
- Samples taken from breathing zone: yes/no

VEHICLE
- Composition of vehicle (if applicable):
- Concentration of test material in vehicle (if applicable):
- Justification of choice of vehicle:
- Lot/batch no. (if required):
- Purity:

TEST ATMOSPHERE (if not tabulated)
- Particle size distribution:
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.):

CLASS METHOD (if applicable)
- Rationale for the selection of the starting concentration:
Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
4 min
Concentrations:
5.25 +/- 0.13 g/m3
No. of animals per sex per dose:
5 male and 5 female rats
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Necropsy of survivors performed: yes
Other examinations performed: clinical signs, and body weight

Results and discussion

Preliminary study:
Preliminary study trials were used to generate a test atmosphere with the test material and a MMAD was used to measure particle size distribution
Effect levels
Key result
Sex:
male/female
Dose descriptor:
LC50
Effect level:
ca. 5.25 other: g/m3
Based on:
test mat.
Exp. duration:
4 h
Mortality:
No mortality occurred during exposure or during the 14-day observation period.
Clinical signs:
other: Clinical signs during exposure consisted of a slightly decreased breathing rate, observed in eight animals, and slight laboured breathing, observed in one animal. Shortly after exposure, all animals felt cold. Black discolouration of the head was observed
Body weight:
Overall body weight gain in males was considered to be within normal limits for animals of this strain and age. Overall body weight gain in females was considered to be within normal limits during the first week of the observation period, and low during the second week of the observation period.
Gross pathology:
At necropsy, treatment-related macroscopic changes consisted of grey discolouration of the lungs in seven animals.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The 4-hour LC50 value of an aerosol of Tungsten disulfide was larger than 5.25 g/m3 for both sexes.
Executive summary:

The acute inhalation toxicity of tungsten disulphide was studied by nose-only exposure of one group of five male and five female rats for a 4-hour period to a test atmosphere containing an aerosol of tungsten disulphide at the limit concentration of 5.25 ± 0.13 g/m3The Mass Median Aerodynamic Diameter of the particles in the test atmosphere was measured once before and once during exposure and yielded 2.7 and 3.0µm, respectively. The distribution of particle sizes had a geometric standard deviation of 1.9 in both instances. After exposure, the animals were kept for a 14-day observation period. Clinical signs during exposure consisted of a slightly decreased breathing rat in right animals as well as labored breathing in one animal. All animls felt cold after exposure and had a black discoloration on their heads. The overall body weight gain in males were considered to be within normal limts. Overall body weight gain in females was considered to be within normal limits during the first week of the observation period, and low during the second week of the observation period.
No mortality occurred during exposure or during the 14 -day observation period.The 4-hour LC50 value of an aerosol of tugsten disulphide was larger than 5.25 g/m3   for both sexes.