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EC number: 273-761-1 | CAS number: 69012-64-2 Amorphous silicon dioxide particles from the volatilization and vaporization of furnace feed materials in the manufacture of ferrosilicon and silicon.
- 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
Endpoint summary
Administrative data
Description of key information
Animal data on the acute toxicity of synthetic amorphous silica, which have been used for read-across, do not show acute oral, inhalation or dermal toxicity.
Key value for chemical safety assessment
Acute toxicity: via oral route
Link to relevant study records
- Endpoint:
- acute toxicity: oral
- Type of information:
- other: OECD evaluation of an in vivo skin irritation study
- Adequacy of study:
- weight of evidence
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: A scientific review by authorative international body
- Reason / purpose for cross-reference:
- reference to same study
- Principles of method if other than guideline:
- OECD evaluated the available test data on synthetic amorphous silica.
- GLP compliance:
- no
- Remarks:
- review: both yes and no status
- Test type:
- other: different acute oral toxicity tests
- Species:
- other: rat and mouse
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- > 5 110 mg/kg bw
- Remarks on result:
- other: hydrophilic precipitated silica
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- > 5 000 mg/kg bw
- Remarks on result:
- other: hydrophilic precipitated silica
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- > 10 000 mg/kg bw
- Remarks on result:
- other: several silica types
- Sex:
- male/female
- Dose descriptor:
- LD0
- Effect level:
- > 20 000 mg/kg bw
- Remarks on result:
- other: hydrophilic precipitated silica
- Sex:
- male
- Dose descriptor:
- LD50
- Effect level:
- > 3 160 mg/kg bw
- Remarks on result:
- other: hydrophilic pyrogenic silica
- Interpretation of results:
- practically nontoxic
- Remarks:
- Migrated information Criteria used for interpretation of results: OECD GHS
- Conclusions:
- OECD (2004) includes 12 acute oral toxicity studies with synthetic amorphous silica, of which five is regarded as critical study for SIDS endpoint. These five studies are conducted with hydrophilic precipitated or pyrogenic silica. In the critical studies, the LD50 or LDO value was at least >3160 mg/kg bw, thus showing no acute oral toxicity.
- Executive summary:
In OECD (2004), the acute oral administration of hydrophilic precipitated or pyrogenic silica either by gavage or in the diet
failed to produce signs of toxicity or deaths in treated animals with LD50 values greater than the top doses applied. Thus, the LD50 values varied from >3100 to >20000 mg/kg bw. In conclusion, acute oral ingestion to high doses of synthetic amorphous silica will produce no systemic toxicity.- Endpoint:
- acute toxicity: oral
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 21 Aug. - 04 Sep. 1990
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 401 (Acute Oral Toxicity)
- GLP compliance:
- yes
- Test type:
- standard acute method
- Limit test:
- yes
- Species:
- rat
- Strain:
- Wistar
- Sex:
- male/female
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Source: Winkelmann Versuchstierzucht, Borchen/Germany
- Age at study initiation: 9 wks (male), 10 wks (females)
- Weight at study initiation: 183 - 191 g (male), 141 - 152 g (female)
- Fasting period before study: 16 h before start
- Housing: single in Macrolon cages
- Water: ad libitum
- Acclimation period: >= 5 days
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20.5 - 22.5 °C
- Humidity (%): 40 - 70 %
- Air changes (per hr):
- Photoperiod (hrs dark / hrs light): 12 / 12 hours
- Route of administration:
- oral: gavage
- Vehicle:
- other: aqueous suspension with 1 % carboxymethyl cellulose
- Details on oral exposure:
- VEHICLE
- Concentration in vehicle: 237 mg silica/mL suspension
- Amount of vehicle (if gavage): 21.5 ml/kg bw (including 5100 mg TS)
- Justification for choice of vehicle: suspending the test material and stabilising the suspension
- Lot/batch no. (if required):
MAXIMUM DOSE VOLUME APPLIED: 21.5 ml/kg bw
- Doses:
- 5110 mg/kg bw
237 mg/ml - No. of animals per sex per dose:
- 5
- Control animals:
- no
- Details on study design:
- - Duration of observation period following administration: 14 days
- Frequency of observations and weighing: days 0, 7, and 14
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight - Statistics:
- not relevant
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- > 5 000 mg/kg bw
- Mortality:
- none
- Clinical signs:
- other: no particular findings
- Gross pathology:
- no particular findings
- Interpretation of results:
- other: non-toxic
- Executive summary:
Jahn et al (1990) studied the acute oral toxicity of precipitated silica in rats. Five male and 5 female animals were used. The dose was applied by gavage as aqueous suspension (21.5 ml/kg bw = 237 mg silica/ml suspension). No acute effects were observed, and the LD50 value was >5,000 mg/kg.
- Endpoint:
- acute toxicity: oral
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- weight of evidence
- Justification for type of information:
- No toxicological data were available for silica fume and, therefore, a read-across approach was used. The dissolution, composition and surface properties were the most important parameters considered when deciding which substances can be used for read-across.
Based on the composition, surface characteristics, and bioaccessibility data, silica fume was assumed to have toxicological properties similar to those of sparingly synthetic amorphous silicas. Therefore read-across was carried out using available toxicological studies with synthetic amorphous silica (SAS).
Details on the read-across approach are presented in Iuclid section 13. - Reason / purpose for cross-reference:
- read-across source
- Reason / purpose for cross-reference:
- read-across source
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- > 5 000 mg/kg bw
- Interpretation of results:
- GHS criteria not met
- Conclusions:
- Acute toxicity studies on synthetic amorphous silica suggest low toxicity.
Referenceopen allclose all
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed
Acute toxicity: via inhalation route
Link to relevant study records
- Endpoint:
- acute toxicity: inhalation
- Type of information:
- other: A scientific review by an authorative international body
- Adequacy of study:
- weight of evidence
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- data from handbook or collection of data
- Reason / purpose for cross-reference:
- reference to same study
- Principles of method if other than guideline:
- OECD evaluated the available test data on synthetic amorphous silica.
- GLP compliance:
- no
- Remarks:
- 'yes' status in critical studies
- Test type:
- other: different acute inhalation toxicity tests
- Species:
- rat
- Sex:
- male/female
- Dose descriptor:
- LC0
- Effect level:
- > 0.139 mg/L air
- Exp. duration:
- 4 h
- Remarks on result:
- other: hydrophilic pyrogenic silica
- Sex:
- male/female
- Dose descriptor:
- LC0
- Effect level:
- > 0.691 mg/L air
- Exp. duration:
- 4 h
- Remarks on result:
- other: hydrophilic precipitated silica
- Sex:
- male/female
- Dose descriptor:
- LC50
- Effect level:
- > 2.08 mg/L air
- Exp. duration:
- 4 h
- Remarks on result:
- other: hydrophilic pyrogenic silica
- Interpretation of results:
- practically nontoxic
- Remarks:
- Migrated information Criteria used for interpretation of results: OECD GHS
- Conclusions:
- OECD (2004) includes seven acute inhalation toxicity studies with synthetic amorphous silica, of which three are regarded as critical studies for SIDS endpoint. These three studies are conducted with hydrophilic pyrogenic or precipitated silica. In a study where LC50 >2.08 mg/L was suggested, none of the animals died. The SAS dusts are considered as acutely non-toxic.
- Executive summary:
The OECD (2004) reviewed that there was no lethal effects following inhalation exposure of rats to the highest technically feasible concentrations of 140 to 2,000 mg/m3 of hydrophilic precipitated or pyrogenic silica. However, the acute inhalation of synthetic amorphous silica dust may cause discomfort and stress as well as signs of local irritation to the nasal, bronchiolar and ocular mucous membranes. In conclusion, the synthetic amorphous silica dust is considered to be acutely non-toxic via an inhalation route.
- Endpoint:
- acute toxicity: inhalation
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- weight of evidence
- Justification for type of information:
- No toxicological data were available for silica fume and, therefore, a read-across approach was used. The dissolution, composition and surface properties were the most important parameters considered when deciding which substances can be used for read-across.
Based on the composition, surface characteristics, and bioaccessibility data, silica fume was assumed to have toxicological properties similar to those of sparingly synthetic amorphous silicas. Therefore read-across was carried out using available toxicological studies with synthetic amorphous silica (SAS).
Details on the read-across approach are presented in Iuclid section 13. - Reason / purpose for cross-reference:
- read-across source
- Dose descriptor:
- LC50
- Effect level:
- > 2.08 mg/L air
- Interpretation of results:
- GHS criteria not met
- Conclusions:
- The OECD (2004) reviewed that there was no lethal effects following inhalation exposure of rats to the highest technically feasible concentrations of 140 to 2,000 mg/m3 of hydrophilic precipitated or pyrogenic silica.
Referenceopen allclose all
All acute inhalation studies performed with dry dust were hampered by the technical problem to achieve the recommended highest test concentration of 5 mg/l, apparently attributable to the high adhesive forces which caused rapid precipitation onto equipment walls. Therefore, the maximum attainable chamber concentrations were distinctly lower than envisaged.
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed
Acute toxicity: via dermal route
Link to relevant study records
- Endpoint:
- acute toxicity: dermal
- Type of information:
- experimental study
- Adequacy of study:
- weight of evidence
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- comparable to guideline study
- Qualifier:
- no guideline available
- Principles of method if other than guideline:
- Four animals per group used, two each treated on the intact and abraded skin: The substance was mixed with distilled water to form an aqueous paste
- GLP compliance:
- no
- Test type:
- standard acute method
- Species:
- rabbit
- Strain:
- New Zealand White
- Sex:
- not specified
- Type of coverage:
- occlusive
- Vehicle:
- water
- Details on dermal exposure:
- Four animals per group used, two each treated on the intact and abraded skin: The substance was mixed with distilled water to form an aqueous paste
- Duration of exposure:
- 24 h
- Doses:
- 2000, 3000, 4000, and 5000 mg/kg
- No. of animals per sex per dose:
- 4 per dose group
- Details on study design:
- - Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight, organ weights - Sex:
- not specified
- Dose descriptor:
- LD50
- Effect level:
- > 5 000 mg/kg bw
- Interpretation of results:
- GHS criteria not met
- Executive summary:
In 1978, Woltjen and Calkins presented their study results on the acute dermal toxicity of precipitated synthetic silicas in four different reports. After acute dermal application of up to 5,000 mg/kg bw of aqueous pastes of precipitated synthetic amorphous silica to the intact and abraded skin of rabbits for 24 hours under occlusive conditions, no signs of systemic or organ toxicity were noted. There were only very slight transient erythemas at the site of treatment in solitary animals. In conclusion, the dermal exposure to high doses of synthetic amorphous silica will produce no systemic toxicity and the LD50 is >5,000 mg/kg.
- Endpoint:
- acute toxicity: dermal
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- weight of evidence
- Justification for type of information:
- No toxicological data were available for silica fume and, therefore, a read-across approach was used. The dissolution, composition and surface properties were the most important parameters considered when deciding which substances can be used for read-across.
Based on the composition, surface characteristics, and bioaccessibility data, silica fume was assumed to have toxicological properties similar to those of sparingly synthetic amorphous silicas. Therefore read-across was carried out using available toxicological studies with synthetic amorphous silica (SAS).
Details on the read-across approach are presented in Iuclid section 13. - Reason / purpose for cross-reference:
- read-across source
- Dose descriptor:
- LD50
- Effect level:
- > 5 000 mg/kg bw
- Interpretation of results:
- GHS criteria not met
- Conclusions:
- After acute dermal application of up to 5,000 mg/kg bw of aqueous pastes of precipitated synthetic amorphous silica to the intact and abraded skin of rabbits for 24 hours under occlusive conditions, no signs of systemic or organ toxicity were noted. Conclusion: No classification for acute toxicity via dermal exposure.
Referenceopen allclose all
Local effect: very slight erythema (score 1 of 4),
reversible after 2 days (ZEO 49), after 4 d (ZEOSYL) or 5 d
(ZEOFREE) in one or a few animals. No systemic signs of
toxicity or organ toxicity.
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed
Additional information
There is data available on the acute toxicity of synthetic amorphous silica. According to this data, the acuteoraltoxicity of synthetic amorphous silica is very low: no signs of toxicity were observed at doses of up to 5,000 mg SiO2/kg bw. The LD50values for the various types of synthetic amorphous silica studied were quite similar. Also, the dermal toxicity of synthetic amorphous silica is low. Available in vitro dissolution data on synthetic biological fluids shows that the bioaccessibility of silicon ion from silica fume is similar or slightly lower than from synthetic amorphous silica. Thus, the bioavailability of silica fume is expected to be similar or lower than that of synthetic amorphous silica. Based on the read-across from synthetic amorphous silica, silica fume is not acutely toxic orally or dermally.
Animal studies with synthetic amorphous silica do not show any acute inhalation toxicity up to the highest technically achievable doses. Available in vitro dissolution data in synthetic biological fluids and comparative toxicokinetic data suggest that the lung kinetics of silica fume is likely to be similar or slightly slower than that of synthetic amorphous silica. Thus, the read-across from synthetic amorphous silica is justified and no acute inhalation toxicity is expected with silica fume.
The dissolution of impurities from silica fume is generally low and in most cases comparable to that from synthetic amorphous silica. Therefore, they are not likely to hamper the read across from synthetic amorphous silica in the case of acute toxicity.
Justification for classification or non-classification
Based on the read-across from synthetic amorphous silicas, silica fume is not acutely toxic via the oral, inhalation or dermal route.
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