Reaction mass of Silicic acid, calcium salt and Silicic acid, magnesium salt

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Remarks:

Reliabality according to OECD SIDS (2004).

Data source

Reference

Reference Type:

other: Collection of data from published literature and company data.

Title:

Unnamed

Year:

2004

Materials and methods

Principles of method if other than guideline:

Nose-only exposure system. Five animals each per sex were used. Analysed chamber concentrations ranged from 650 to 725 mg/m3 (note:
Technically, the maximally achievable aerosol concentration due to substance-inherent properties resulting in sedimentation and adsorption to
the equipment.). About 45 % of the aerosol comprised particles with an aerodynamic diameter of <5 um (respirable fraction).

GLP compliance:

yes

Test material

Test material information

Constituent 1

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

Specific details on test material used for the study:

SIPERNAT 22S >98 % (SiO2): CAS-Name: Silica, precipitated, cryst.-free; CAS-No.: 112926-00-8. Surface area: 160 - 195 m2/g.

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Administration / exposure

Route of administration:

inhalation

Type of inhalation exposure:

nose only

Vehicle:

not specified

Duration of exposure:

4 h

Concentrations:

Maximum attainable concentration: 691 mg/m3. Analysed chamber concentrations ranged from 650 to 725 mg/m3.

No. of animals per sex per dose:

Five animals each per sex.

Control animals:

not specified

Details on study design:

Analysed chamber concentrations ranged from 650 to 725 mg/m3 (Technically, the maximally achievable aerosol concentration due to substance-inherent properties resulting in sedimentation and adsorption to
the equipment.). About 45 % of the aerosol comprised particles with an aerodynamic diameter of <5 um (respirable fraction).

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LC0

Effect level:

> 0.691 mg/L air

Mortality:

None

Clinical signs:

other: No clinical symptoms except some restlessness and eye closing.

Body weight:

No clinical symptoms except some restlessness and eye closing. Body weight gain was not affected in males, but females hardly gained weight
during two days after exposure, however, subsequently, showed normal development.

Gross pathology:

No findings at autopsy after 14 d post-treatment.

Applicant's summary and conclusion

Conclusions:

Acute inhaltation toxicity of synthetic amorphous silicon dioxide (precipitated) in rat: LC0 (4 h) >0.691 mg/L.

Executive summary:

An acute inhaltation toxicity study with precipitated synthetic amorphous silicon dioxide was performed using rat as a test organism. Analysed chamber concentrations ranged from 650 to 725 mg/m3 (maximum attainable concentration was 691 mg/m3). No clinical symptoms except some restlessness and eye closing. Body weight gain was not affected in males, but females hardly gained weight during two days after exposure, however, subsequently, showed normal development. No findings at autopsy after 14 d post-treatment.