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Diss Factsheets
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EC number: 945-327-8 | CAS number: -
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Repeated dose toxicity: inhalation
Administrative data
- Endpoint:
- short-term repeated dose toxicity: inhalation
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- study well documented, meets generally accepted scientific principles, acceptable for assessment
- Remarks:
- The secondary literature is a compilation of four bioassay studies implemented to compare pulmonary responses in rats after short-term inhalation exposure to various silica dust.
Data source
Reference
- Reference Type:
- publication
- Title:
- Differential pulmonary responses in rats inhaling crystalline, colloidal or amorphous silica dusts
- Author:
- Warheit DB, McHugh TA, Hartsky MA
- Year:
- 1 995
- Bibliographic source:
- Scand J Work Environ Health
Materials and methods
- Principles of method if other than guideline:
- The compiled bioassays were designed to evaluate pulmonary responses in rats after short-term inhalation exposure
to two forms of crystalline silica, one form of amorphous silica and one form of colloidal silica particles.
Rats were exposed for 3 days at aerosol concentrations of either 10 or 100 mg/m3 precipitated amorphous silica. Cells and fluids from sham- and silica-exposed rats were recovered by bronchoalveolar lavage (BAL). Lactate
dehydrogenase (LDH), protein, and N-acetyl glucosaminidase (NAG) were repeatedly measured in BAL fluids postexposure. - GLP compliance:
- not specified
Test material
- Reference substance name:
- Silicon dioxide
- EC Number:
- 231-545-4
- EC Name:
- Silicon dioxide
- Cas Number:
- 7631-86-9
- Molecular formula:
- O2Si
- IUPAC Name:
- Silicon dioxide
- Test material form:
- solid
Constituent 1
- Specific details on test material used for the study:
- Synthetic amorphous silicon dioxide, precipitated. CAS no.: 112926-00-8, Zeofree 80, 2.4-3.4 µm.
Test animals
- Species:
- rat
- Strain:
- other:
- Remarks:
- CD rats
- Sex:
- not specified
- Details on test animals or test system and environmental conditions:
- 24 CD rats were exposed for 3 days at 10 mg/m3 or 100 mg/m3 amorphous silica.
Administration / exposure
- Route of administration:
- inhalation: dust
- Type of inhalation exposure:
- not specified
- Vehicle:
- not specified
- Mass median aerodynamic diameter (MMAD):
- >= 2.4 - <= 3.4 µm
- Analytical verification of doses or concentrations:
- not specified
- Duration of treatment / exposure:
- 6 h a day for 3 days.
Doses / concentrationsopen allclose all
- Dose / conc.:
- 10 mg/m³ air
- Dose / conc.:
- 100 mg/m³ air
- No. of animals per sex per dose:
- Not specified
- Control animals:
- yes
- yes, sham-exposed
Examinations
- Observations and examinations performed and frequency:
- Cells and fluids from sham- and silica-exposed rats were recovered by bronchoalveolar lavage (BAL). Lactate
dehydrogenase (LDH), protein, and N-acetyl glucosaminidase (NAG) were repeatedly measured in BAL fluids postexposure.
Results and discussion
Results of examinations
- Clinical signs:
- not specified
- Mortality:
- not specified
- Body weight and weight changes:
- not specified
- Food consumption and compound intake (if feeding study):
- not specified
- Food efficiency:
- not specified
- Water consumption and compound intake (if drinking water study):
- not specified
- Ophthalmological findings:
- not specified
- Haematological findings:
- not specified
- Clinical biochemistry findings:
- effects observed, treatment-related
- Description (incidence and severity):
- Following exposure to amorphous silicon dioxide, a transient inflammatory response was observed, characterized by the presence of granulocytes
(primarily neutrophils) in BAL fluids. The response was abrogated within 8 days post-exposure. Exposure to amorphous silica also resulted in pulmonary toxicity characterized as extracellular LDH in the BAL fluids. The BAL fluid LDH values increased within 24 h following exposure, however, returned to control values within 8 days post-exposure. NAG values in rats exposed to amorphous silica were not significantly different to controls following 8 days postexposure. - Urinalysis findings:
- not specified
- Behaviour (functional findings):
- not specified
- Immunological findings:
- not specified
- Organ weight findings including organ / body weight ratios:
- not specified
- Gross pathological findings:
- not specified
- Neuropathological findings:
- not specified
- Histopathological findings: non-neoplastic:
- not specified
- Histopathological findings: neoplastic:
- not specified
Effect levels
- Key result
- Dose descriptor:
- other: See "Remarks"
- Remarks:
- Exposure to synthetic amorphous silicon dioxide (10 and 100 mg/m3) gave rise to a transient inflammatory response which was present 24 h post-exposure. Within 8 days post-exposure, this effect was abrogated.
- Based on:
- not specified
- Sex:
- not specified
- Basis for effect level:
- clinical biochemistry
- Remarks on result:
- other: See "Remarks"
- Remarks:
- Exposure to synthetic amorphous silicon dioxide (10 and 100 mg/m3) gave rise to a transient inflammatory response which was present 24 h post-exposure. Within 8 days post-exposure, this effect was abrogated. No effect level was specified.
Target system / organ toxicity
- Key result
- Critical effects observed:
- not specified
- Lowest effective dose / conc.:
- 10 mg/m³ air
- System:
- other: Inflammatory response in lungs of rats characterized by the presence of granulocytes (primarily neutrophils) in BAL fluids.
- Organ:
- lungs
Any other information on results incl. tables
A pulmonary inflammatory response was seen in lungs of rats following exposure to amorphous silicon dioxide. Within 8 days post-exposure, this effect was abrogated. Exposure to amorphous silica also resulted in pulmonary toxicity characterized as extracellular LDH in the BAL fluids. The BAL fluid LDH values increased within 24 h following exposure, however, returned to control values within 8 days post-exposure. NAG values of rats exposed to amorphous silica were not significantly different from control animals following 8 days postexposure.
Applicant's summary and conclusion
- Conclusions:
- A pulmonary inflammatory response was seen in lungs of rats following exposure to amorphous silicon dioxide via inhalation (10 and 100 mg/m3). Within 8 days post-exposure, this effect was abrogated. Exposure to amorphous silica also resulted in pulmonary toxicity characterized as extracellular LDH in the BAL fluids. The BAL fluid LDH values increased within 24 h following exposure, however, returned to control values within 8 days post-exposure. NAG values of rats exposed to amorphous silica were not significantly different from control animals following 8 days postexposure. Taken together, exposure to amorphous silica particles via inhalation gave rise to a transient pulmonary inflammatory response in rats.
- Executive summary:
The study was designed to investigate pulmonary responses in rats following short-term inhalation exposure to different silicas including amorphous silica. A pulmonary inflammatory response was seen in lungs of rats following exposure to amorphous silicon dioxide for 6 h a day for 3 days (10 and 100 mg/m3). Within 8 days post-exposure, this effect was abrogated. Exposure to amorphous silica also resulted in pulmonary toxicity characterized as extracellular LDH in the BAL fluids. The BAL fluid LDH values increased within 24 h following exposure, but returned to control values within 8 days post-exposure. NAG values of rats exposed to amorphous silica were not significantly different from control animals following 8 days postexposure. It was concluded that the crystalline forms of silica dust were much more potent in terms of producing pulmonary toxicity compared to amorphous or colloidal forms of silica.
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