Silicate(2-), hexafluoro-, disodium, reaction products with lithium magnesium sodium silicate

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1983

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Test carried out by GLP compliant laboratory to recognised validated methods by trained personnel

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1983

Report date:

1983

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

Twenty rats (10 male, 10 female) were weighed and checked for health issues and acclimatised in a holding room prior to test initiation. They were housed in controlled humidity and temperature conditions. Ten rats were used for the substance exposure and 10 rats used for the control (clean air). Each rat was placed in individual compartments within a 0.13 cubic meter perspex chamber. Air flow was 25l/min (measured at the generator outlet)and the test material in powder form was introduced via this air stream for a period of 4 hours following a 12 minute equilibration period. The air was sampled 5 times during the 4 hour period and the particle size of the dust was also measured. After exposure the rats were returned to their cage and observed for signs of pharmacotoxic effects and mortality continuously after exposure and then at least twice daily for 14 days. After this time the rats were euthenased and subjected to gross necropsy.

GLP compliance:

yes

Test type:

fixed concentration procedure

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Silicate(2-), hexafluoro-, disodium, reaction products with lithium magnesium sodium silicate

EC Number:

285-349-9

EC Name:

Silicate(2-), hexafluoro-, disodium, reaction products with lithium magnesium sodium silicate

Cas Number:

85085-18-3

Molecular formula:

Na0.7[Mg5.3Li0.7Si8O20(OH)0.0F4.0]

IUPAC Name:

Synthetic fluorohectorite

Details on test material:

The test material used for this inhalation study was Laponite B, supplied Dec 1982

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Administration / exposure

Route of administration:

inhalation: dust

Type of inhalation exposure:

whole body

Vehicle:

air

Analytical verification of test atmosphere concentrations:

not specified

Duration of exposure:

240 min

Concentrations:

Durin the exposure, 5 samples were taken and the dust level ranged between 1.45 0 1.84 g/cubic meter. The average value was determined to be 1.66g/m3. This was the highest practical concentration that could be achieved with the apparatus used for the test. the PSD analysis showed that~47% of the dust was 5.5 microns or less and therefore in the respirable size region

No. of animals per sex per dose:

Exposed to the dust - 5 males, 5 females
Exposed to clean air (control) - 5 males, 5 females

Control animals:

yes

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 1 660 mg/m³ air

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No deaths were recorded following exposure of 10 rats to Laponite B dust at 1.66g/m3, which was the highest practical level attainable.

Clinical signs:

other: During the exposure: licking of the inside of the mouth, partial closure of eyes, abnormal breathing, lacrimation and lethargy in some animals. Signs were consistent with exposure to a mildly irritant dust. During the observation period: abnormal breathi

Body weight:

For the rats exposed to the dust there was a slight reduction in rate of group mean bodyweight on the day following exposure but after that, the rate of weight gain was similar to the control group.

Gross pathology:

The lung weight to bodyweight ratio were considered to be within normal limits.

Applicant's summary and conclusion

Interpretation of results:

practically nontoxic

Remarks:

Migrated information Criteria used for interpretation of results: expert judgment

Conclusions:

This test substance is not toxic to rats by inhalation under conditions of this test

Executive summary:

The level of dust in the air as supplied by the methodology of the test could not be produced at a higher concentration than 1.66mg/l, this was the highest attainable level. At this level, there was no mortality or signs of toxicity exhibited by the exposed rats. As it was not possible to produce sufficiently high concentrations in the atmosphere to cause adverse effects, classification is not considered necessary.  The maximum achieved concentration of 1.66 mg/l is used as part of the derivation of no effect levels