Silicic acid, potassium salt

Endpoint summary

Description of key information

oral: LD50 (rat, female) > 5000 mg/kg bw
inhalation: LC50 (rat) > 2.06 g/m3
dermal: LD50 (rat) > 5000 mg/kg bw

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

19 Oct 2004 - 16 Dec 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Meets national standard methods, GLP

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1100 (Acute Oral Toxicity)

Deviations:

no

GLP compliance:

yes

Remarks:

Product Safety Laboratories

Test type:

up-and-down procedure

Limit test:

yes

Species:

rat

Strain:

other: Sprague-Dawley derived albino

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Ace Animals, Inc., Boyertown
- Age at study initiation: 10 weeks
- Weight at study initiation: 179 - 190 g
- Fasting period before study: overnight
- Housing: singly in suspended stainless steel cages
- Diet (e.g. ad libitum): Purina Rodent Chow #5012
- Water (e.g. ad libitum): filtered tap water
- Acclimation period: 15 - 16 days


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


IN-LIFE DATES: From: 20 Oct To: 4 Nov 2004

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Doses:

5000 mg/kg

No. of animals per sex per dose:

3

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: frequently during the first several hours and daily thereafter
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight

Sex:

female

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

Remarks on result:

other: No effects on body weight. All animals were active and healthy throughout the experiment. At necropsy, no gross abnormalities were found.

Reference 2

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test procedure according to national standards; report with limited detail.

Principles of method if other than guideline:

Standard acute oral toxicity test (partly in agreement with OECD 401). Only survivors were macroscopically examined upon autopsy. The report is very limited in detail.

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

other: Cpb:Wu, Wistar Random

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ORGANISMS:
- Source: Central Institute for the Breeding of Laboratory Animals TNO, Zeist, Netherlands
- Age: "Young adult albino rats"
- Weight at study initiation: 234-314 g (males) and 132-204 g (females)

Route of administration:

oral: unspecified

Vehicle:

not specified

Doses:

2.50, 3.00, 3.60, 4.32, 5.20 mL/kg bw

No. of animals per sex per dose:

5

Control animals:

not specified

Sex:

male/female

Dose descriptor:

LD50

Effect level:

5 700 mg/kg bw

MORTALITY:
- Time of death: deaths occured between 2 hours and 2 days after dosing
- Number of deaths at each dose: 1 at dose 2.50 ml/kg, 2 at dose 3.00 ml/kg, 2 at dose 3.60 ml/kg, 3 at dose 4.32 ml/kg and all 10 at dose 5.20 ml/kg. 
CLINICAL SIGNS:

Sedation and signs of discomfort were observed within few hours after treatment and later on sluggishness and unconsciousness were frequently observed. The effects were reversible in the recovery period of the
surviving animals.
NECROPSY FINDINGS:

No treatment-related gross alterations

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

19 Oct 2004 - 16 Dec 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Meets national standard methods; GLP

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

Deviations:

no

GLP compliance:

yes

Remarks:

Product Safety Laboratories

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

other: Sprague-Dawley derived albino

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Ace Animals, Inc., Boyertown
- 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
- Diet (e.g. ad libitum): Purina Rodent Chow #5012
- Water (e.g. ad libitum): tap wter
- 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

Route of administration:

inhalation: vapour

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, humidity, pressure in air chamber:


TEST ATMOSPHERE
- Brief description of analytical method used: Gravimetric samples were collected with filter papers which were wighed before and after collection to determine the mass collected. This value was devided by the total vlume 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: 9 µM: 4%, 5.8 µm: 8.3%, 4.7 µm: 11.1%, 3.3 µm: 12%, 2.1 µm: 32%, 1.1 µm: 22.6%, 0.7 µm: 7.4%, 0.4 µm: 2.6%
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): 2.7 µm/1.96

Analytical verification of test atmosphere concentrations:

yes

Remarks:

see above

Duration of exposure:

4.4 h

Concentrations:

2.06 ± 0.19 mg/L

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: in chamber animal observations and at least daily following exposure; body weights were recorded prior to exposure and again on days 7 and 14
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight,organ weights, histopathology, other:

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 2.06 mg/L air (analytical)

Exp. duration:

4 h

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. All animals survived exposure to the test atmosphere and gained body weight over the 14 -day period. No gross abnormalities were noted for any of the animals at terminal necropsy.

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

19 Oct 2004 - 16 Dec 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Meets national standard methods; GLP

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1200 (Acute Dermal Toxicity)

Deviations:

no

GLP compliance:

yes

Remarks:

Product Safety Laboratories

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

other: Sprague-Dawley derived albino

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Ace Animals Inc., Boyertown
- Age at study initiation: 8 -9 weeks
- Weight at study initiation: 251 - 280 g (males) and 175 - 210 g (females)
- Housing: sngly in stainless steel cages
- Diet (e.g. ad libitum): Purina Rodent Chow #5012
- Water (e.g. ad libitum): filtered tap water
- Acclimation period: 8 days


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


IN-LIFE DATES: From: 20 Oct To: 3 Nov 2004

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- Area of exposure: dorsal area and the trunk
- % coverage: 10 (2 inches x 3 inches)
- Type of wrap if used: Durapore tape


REMOVAL OF TEST SUBSTANCE
- Washing (if done): the test sites were gently cleansed
- Time after start of exposure: 24 h


TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.71 - 1.1 mL depending on body weight
- Concentration (if solution): 30%

Duration of exposure:

24 h

Doses:

5000 mg/kg bw

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: frequently during the first sevral hours after application and at least once daily thereafter
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

All animals survived, gained body weight and appeared healthy and active. Apart from the dermal irritation (erythema) and alopecia noted at the application site of five animals (4 females and 1 male) between days 1 and 8, there were no other signs of toxicity. No gross lesions were observed at final necropsy in any animal.

Additional information

Potassium silicates of varying concentrations have been tested in rats for their acute toxicity.
Clinical effects observed in the above mentioned studies included sedation, signs of irritation (only after dermal and inhalation exposure) and sluggishness. All effects were reversible. No treatment-related gross alterations were found at necropsy. The LD₅₀(oral and dermal route) was above 5000 mg/kg bw. The LC₅₀was > 2.06 mg/m³.

The studies on potassium silicate fit well into the toxicity pattern of the sodium silicates: Inverse correlation of acute oral toxicity of soluble silicates to the molar ratio SiO₂/Na₂O. Toxicity decreases in rats with increasing molar ratio from LD₅₀ of 500 mg/kg bw for molar ratio 0.5 to 8650 mg/kg bw for 3.38.

Justification for classification or non-classification

The available data is conclusive but not sufficient for classification.