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Toxicological information

Acute Toxicity: inhalation

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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:
supporting study
Study period:
21 Oct 2004 - 4 Nov 2004
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
GLP-study, which meets national standard methods tested with the source substance AgSil TM 25 Potassium Silicate Solution. According to the ECHA guidance document “Practical guide 6: How to report read-across and categories (March 2010)”, the reliability was changed from RL1 to RL2 to reflect the fact that this study was conducted on a read-across substance.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report Date:
2004

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EPA OPPTS 870.1300 (Acute inhalation toxicity)
Version / remarks:
1998
Deviations:
no
GLP compliance:
yes
Remarks:
Product Safety Laboratories
Test type:
standard acute method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): AgSil TM 25 Potassium Silicate Solution
- Physical state: claer to hazy white, thick liquid
- Composition of test material, percentage of components: 70% water, 30% silicic acid, potassium salt, potassium silicate
- Lot/batch No.: C052804K1
- Stability under test conditions: stable for the duration of testing
- Storage condition of test material: at room temperature
- Other: ratio: 2.47; pH: 11.3

Test animals

Species:
rat
Strain:
other: Sprague-Dawley derived albino
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Ace Animals, Inc., Boyertown, PA, USA
- Age at study initiation: 8 - 9 weeks
- Weight at study initiation: 255 - 285 g (males) and 180 - 205 g (females)
- Housing: singly in stainless steeel cages with mesh floors
- Diet: Purina Rodent Chow #5012
- Water: tap water ad libitum by an automatic water dispensing system except during exposure
- Acclimation period: 9 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 - 22
- Photoperiod (hrs dark / hrs light): 12/12


IN-LIFE DATES: From: 21 Oct To: 4 Nov 2004

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
whole body
Vehicle:
other: filtered air
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: whole body plexiglas chamber
- Exposure chamber volume: 150 L
- Method of holding animals in test chamber: cages
- Source and rate of air: air compressor, total airflow 45.7 L per minute
- System of generating particulates/aerosols: The test atmosphere was generated using a 1/4 inch JCO atomizer, FC3 fluid cap and 70SS air cap. Compressed air was supplied. The test substance was metered to tthe atomization nozzle through size 14 tygon tubing using a peristaltic pump.
- Method of particle size determination: eight stage Andersen cascade impactor
- Temperature, relative humidity in air chamber: 21 °C, 49 - 75%


TEST ATMOSPHERE
- Brief description of analytical method used: Gravimetric samples were collected with filter papers which were weighed before and after collection to determine the mass collected. This value was devided by the total volume of air sampled to determine the chamber concentration. Sample airflows were measured using a Mass Flowmeter.
- Samples taken from breathing zone: yes


TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: see table 1 under "any other information on materials and methods incl. tables"
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): see table 2 under "any other information on materials and methods incl. tables"
Analytical verification of test atmosphere concentrations:
yes
Remarks:
see above
Duration of exposure:
4 h
Remarks on duration:
equilibrium time is excluded
Concentrations:
2.06 ± 0.19 mg/L (analytical concentration, gravimetric)
34.67 mg/L (nominal concentration)
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: Animals were observed for mortality, signs of gross toxicity, and behavioral changes prior to exposure, at least every 30 min during exposure upon removal from the exposure chamber and at least once daily thereafter for 14 days. Observation included gross evaluation of skin and fur, eyes and mucous membranes, respiratory, circulatory, autonomic and central nervous systems, somatomotor activity and behavior pattern. Particular attention was directed to observation of tremors, convulsions, salivation, diarrhea and coma. Body weights were recorded prior to exposure and again on days 7 and 14.
- Necropsy of survivors performed: yes; all rats were euthanized via CO2 inhalation on day 14. Gross necropsy were performed on all animals. Tissue and organs of hte thoracic and abdominal cavities were examined.

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 2.06 mg/L air (analytical)
Based on:
test mat.
Remarks:
silicic acid, potassium salt solution (30%)
Exp. duration:
4 h
Mortality:
All animals survived exposure to the test atmosphere.
Clinical signs:
other: During exposure, animals showed hunched posture and hypoactivity. All animals recovered from the above clinical signs upon removal from the exposure chamber and appeared healthy and active over the 14 -day observation period.
Body weight:
All animals gained body weight over the 14-day observation period.
Gross pathology:
No gross abnormalities were noted for any of the animals at terminal necropsy.

Applicant's summary and conclusion