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Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: A scientific review by an authoritative international body (OECD).
Cross-reference
Reason / purpose for cross-reference:
reference to same study

Data source

Reference
Reference Type:
review article or handbook
Title:
SIDS initial assessment report for SIAM 19. Synthetic amorphous silica and silicates.
Author:
OECD
Year:
2004
Bibliographic source:
UNEP Publications, Berlin.

Materials and methods

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

Test material

Constituent 1
Reference substance name:
112945-52-5; 112926-00-8
IUPAC Name:
112945-52-5; 112926-00-8
Constituent 2
Reference substance name:
silica, amorphous, fumed, cryst.-free; silica, precipitated, cryst.-free
IUPAC Name:
silica, amorphous, fumed, cryst.-free; silica, precipitated, cryst.-free
Details on test material:
Tradenames: Aerosil 200; Sipernat 22S; other TS - Ludox (30% SiO2) or colloidal silica; Syloid 244; Cab-O-Sil M5

Test animals

Species:
rat

Results and discussion

Effect levelsopen allclose all
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

Any other information on results incl. tables

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.

Applicant's summary and conclusion

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 is regarded as critical study 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.

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