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EC number: 275-735-5 | CAS number: 71630-92-7 Substance obtained by burning the husk removed from the rice paddy. Contains silica as well as the elements aluminum, calcium, carbon, chromium, copper, indium, iron, lead, magnesium, manganese, molybdenum, phosphorus, silver, sodium, tin, and zinc.
- 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
Carcinogenicity
Administrative data
- Endpoint:
- carcinogenicity: oral
- Type of information:
- migrated information: read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- other information
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Basic data given
Data source
Reference
- Reference Type:
- publication
- Title:
- Characterization and toxicological behavior of synthetic amorphous hydrophobic silica
- Author:
- Lewinson, J. et al.
- Year:
- 1 994
- Bibliographic source:
- Regul Toxicol Pharmacol. 20(1 Pt 1):37-57
Materials and methods
- Principles of method if other than guideline:
- Carcinogenicity 24-months study in rats (one dose level)
- GLP compliance:
- not specified
Test material
- Reference substance name:
- Silane, dichlorodimethyl-, reaction products with silica
- EC Number:
- 271-893-4
- EC Name:
- Silane, dichlorodimethyl-, reaction products with silica
- Cas Number:
- 68611-44-9
- IUPAC Name:
- 271-893-4
- Details on test material:
- - Name of test material (as cited in study report): Aerosil R 972 (Fumed Hydrophobic Silica, FHS)
- Analytical purity: >99.8%
Constituent 1
Test animals
- Species:
- rat
- Strain:
- Wistar
- Sex:
- male/female
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Source: Insitute de Medicine legale et Institute d'Hygiene Industrielle et de Medicine du Travail, Marseille, France
- Weight at study initiation: 70 g
- Housing: The animals were housed in metal cages in groups of five animals of the same sex.
- Diet (e.g. ad libitum): MAB1 (Lacassangne, France). The untreated diet was available ad libitum.
Administration / exposure
- Route of administration:
- oral: feed
- Vehicle:
- unchanged (no vehicle)
- Analytical verification of doses or concentrations:
- not specified
- Duration of treatment / exposure:
- 24 months
- Frequency of treatment:
- daily
- Post exposure period:
- no post-exposure period
Doses / concentrations
- Remarks:
- Doses / Concentrations:
100 mg/kg bw
Basis:
nominal conc.
- No. of animals per sex per dose:
- 20
- Control animals:
- yes, historical
Examinations
- Observations and examinations performed and frequency:
- CAGE SIDE OBSERVATIONS: Yes
BODY WEIGHT: Yes
HAEMATOLOGY: Yes - Sacrifice and pathology:
- GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes: lungs, spleen, kidneys, liver, mamma, testes, uterus, ovaries.
Results and discussion
Results of examinations
- Clinical signs:
- no effects observed
- Mortality:
- no mortality observed
- Body weight and weight changes:
- no effects observed
- 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:
- no effects observed
- Clinical biochemistry findings:
- not specified
- Urinalysis findings:
- not specified
- Behaviour (functional findings):
- not specified
- Organ weight findings including organ / body weight ratios:
- not specified
- Gross pathological findings:
- effects observed, treatment-related
- Histopathological findings: non-neoplastic:
- effects observed, treatment-related
- Histopathological findings: neoplastic:
- no effects observed
- Details on results:
- CLINICAL SIGNS AND MORTALITY
No overt clinical signs or changes in behavior or mortality were observed in the test group.
BODY WEIGHT AND WEIGHT GAIN
After administration of the test substance for 24 months, body weights were comparable with those of controls.
HAEMATOLOGY
Hematological and electrophoretic investigations did not show leukosis in any animal. In animals with chronic bronchopneumonia, hyperleukocytosis with polynucleosis and hypergammaglobulinemia were found.
GROSS PATHOLOGY
At autopsy the macroscopical findings were one benign mammary tumor at the left fossa ilia in one male, a small ovarian cyst in one female, and an increase in the size of one ovary in another female. In the lungs of several male and female rats the signs of a chronic bronchopneumonia were observed.
HISTOPATHOLOGY: NON-NEOPLASTIC
The histopathological examinations of the preserved tissues did not revealed treatment-related effects (s. table). Most adverse effects were inflammatory or were classified as spontaeous changes.
HISTORICAL CONTROL DATA (if applicable)
A benign mammary tumor had been observed in historical controls. This tumor was, therefore, considered to be incidental and not related to the treatment. The historical data on this strain at an age of two years have demonstrated an incidence of tumors of the pituitary of less than 5% and of sarcomas of less than 3%. Cutaneous papillomatosis was also observed.
Any other information on results incl. tables
Histopathology for rats fed 100 mg/kg bw Aerosil R 972 for 2 years
|
No. of rats with lesions |
|
Organs and lesions |
Males |
Females |
Lungs: Peribronchial lymphoid tissue, hyperplastic Dilatation bronchi Emphysema foci Focal suppuration |
7/20 7/20 7/20 1/20 |
7/20 7/20 5/20 1/20 |
Spleen: Lymphoid tissue, hyperplastic Red pulpa, increase of plasma cells Red pulpa, reactive |
2/20 7/20 5/20 |
2/20 6/20 4/20 |
Kidneys: Renal tubules, dilatation Granular cylinders |
4/20 3/20 |
3/20 1/20 |
Liver: Inflammatory infiltration |
|
1/20 |
Mamma: Fibrotic adenoma, benign |
1/20 |
|
Testes: Seminiferous tubules, atrophic Glandular tissue, hyperplastic (not tumors) |
1/20 1/20 |
|
Uterus: Mucous membrane, hyperplastic (slight degree) |
|
2/20 |
Ovaries: Atresic follicles Interstitial gland, hyperplastic Serous cyst, benign |
|
2/20 2/20 1/20 |
Comparison of the rates of tumors found in the study with those occurring in historical controls indicated that no carcinogenic effects could be attributed to the exposure.
Applicant's summary and conclusion
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
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