Ammonium hexafluorosilicate

Endpoint summary

Description of key information

Ammonium hexafluorosilicate can be considered as not a skin irritant, however it was to be classified as an eye irritant.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Publication date - 07 May 1982.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: Organisation for Economic Co-operation and Development (1979). OECD Short-term and Lone-term Toxicology’ Groups. Final Report: Acute Dermal Irritation/ Corrosivity. 31 December. p. 35.

Deviations:

not specified

GLP compliance:

no

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

The test was carried out on male albino rabbits of the New Zealand strain, weighing about 2.5 kg and supplied by Roucher SA, Couht. The study was conducted in a single group of six rabbits.

Type of coverage:

occlusive

Preparation of test site:

shaved

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

0.5 g

Duration of treatment / exposure:

4 h

Observation period:

72 h

Number of animals:

6

Irritation parameter:

primary dermal irritation index (PDII)

Basis:

mean

Time point:

other: 1/24/48/72 h

Score:

0.04

Remarks on result:

other: Reversibility not specified

Irritation parameter:

erythema score

Basis:

other:

Remarks:

Only PDI available.

Time point:

24/48/72 h

Remarks on result:

other: Individual scores not available.

Remarks:

Only PDI available.

Irritation parameter:

edema score

Basis:

other:

Remarks:

Only PDI available

Time point:

24/48/72 h

Remarks on result:

other: Individual scores not available.

Remarks:

Only PDI available.

Interpretation of results:

GHS criteria not met

Conclusions:

Sodium fluorosilicate was concluded to be non irritant to the skin.

Executive summary:

The skin irritation potential of sodium fluorosilicate was evaluated by Guillot et al, 1982. The test was carried out on male albino rabbits of the New Zealand strain, weighing about 2.5 kg and supplied by Roucher SA, Couht. The study was conducted in a single group of six rabbits. Each rabbit was clipped over the back and flanks with a fine-toothed electric clipper (Aesculap Type V 42 947).

0.5 g was applied on the shaved skin and the treated skin was covered in each case with a four-layered sterile absorbent-gauze square (2 x 2 cm), which was moistened with 0.5 ml water. The test material and gauze pads were kept in contact with the skin by a patch (Neodermotest Rot SA, Paris) consisting of an occlusive central disc (22 mm in diameter) surrounded by an adhesive hypoallergenit perforated plaster (10 mm wide). Finally an adhesive tape (6 cm wide) was wound round the animal, without restricting respiratory and abdominal movements, to complete the holding of the patches, and the rabbit was placed in a restraining device for at least 4 h. Macroscopic observations were recorded at 1, 24, 48 and 72 h for both after patch removal. Each treated area was scored for erythema and oedema using a numerical system (0-4 in each case according to severity) based on that described by Draize, Woodard & Calvery (1948). The scores obtained for erythema and oedema at both of the treated sites in all six animals at the two or more reading times were totaled. The sum obtained was then divided by the total number of readings to provide a mean score (never greater than 8) termed the primary irritation index (PCI). The following scale was used to interpret the results:

PCI below 0.5: non-irritant; 0.5-3: slightly irritant; 3-5: moderately irritant; 5-8: severely irritant

The primary cutaneous irritation index obtained in this study was 0.04, hence the substance was concluded to be non-irritant to the skin.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

Publication date - 16 June 1960.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

other: technique as described in the "Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics" (1959) of the US Association of Food and Drug Officials (AFDO)

Deviations:

not specified

GLP compliance:

no

Specific details on test material used for the study:

Name: Sodium hexafluorosilicate

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

Three to four months old weighing 1,800 to 2,300 grams were used in these experiments.

Vehicle:

unchanged (no vehicle)

Amount / concentration applied:

Liberal amount of the test substance was inserted in eyes.

Observation period (in vivo):

at least 5 days

Number of animals or in vitro replicates:

For testing with intact eyes, 3 rabbits were used.
For testing with damaged eyes, 2 rabbits were used.

Irritation parameter:

other: Changes in intact eyes

Basis:

other: Slight conjunctival injection was detected in 15 minutes and had cleared completely by 24 hours in two of the rabbits. An acute purulent conjunctivitis developed in one eye of the third rabbit; this healed spontaneously without scarring in 5 days.

Time point:

other: 24 h and 5 d

Reversibility:

fully reversible within: 5 d

Remarks on result:

other: No scoring was done

Irritation parameter:

other: Changes in damaged eyes

Basis:

other: Localized conjunctival injection was noticeable immediately, but the eyes were perfectly normal at 24 hours.

Time point:

24 h

Reversibility:

fully reversible within: 24 h

Remarks on result:

other: Scoring was not done

Interpretation of results:

GHS criteria not met

Conclusions:

Sodium fluorosilicate did not lead to irritation in eyes.

Executive summary:

The potential of sodium fluorosilicate to cause irritation or corrosion in eyes was evaluated in this study conducted with New Zealand White rabbits. For the testing with intact eyes, the dry powdered form of sodium fluosilicate was sprinkled liberally into the undamaged eyes of 3 rabbits. Slight conjunctival injection was detected in 15 minutes and had cleared completely by 24 hours in two of the rabbits. An acute purulent conjunctivitis developed in one eye of the third rabbit; this healed spontaneously without scarring in 5 days. No other abnormalities of the eyes or lids could be detected grossly. To determine the effects on the damaged eye, a 1 cm superficial scratch was made across the cornea onto the sclera of the eyes of two rabbits. The compound was then liberally sprinkled into the eyes. Localized conjunctival injection was noticeable immediately, but the eyes were perfectly normal at 24 hours. Hence, taking into consideration the above results, sodium fluorosilicate can be considered to not lead to irritation in eyes.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation:

Currently no studies are available which evaluate the skin irritation potential of ammonium hexafluorosilicate. However, literature discussing skin irritation potential of sodium hexafluorosilicate is available, which has been presented below:

 

Guillot et al, 1982:

The skin irritation potential of sodium fluorosilicate was evaluated by Guillot et al in 1981 - 1982. The test was carried out on male albino rabbits of the New Zealand strain, weighing about 2.5 kg and supplied by Roucher SA, Couht. The study was conducted in a single group of six rabbits. Each rabbit was clipped over the back and flanks with a fine-toothed electric clipper (Aesculap Type V 42 947). 0.5 g was applied on the shaved skin and the treated skin was covered in each case with a four-layered sterile absorbent-gauze square (2 x 2 cm), which was moistened with 0.5 ml water. The test material and gauze pads were kept in contact with the skin by a patch (Neodermotest Rot SA, Paris) consisting of an occlusive central disc (22 mm in diameter) surrounded by an adhesive hypoallergenic perforated plaster (10 mm wide). Finally an adhesive tape (6 cm wide) was wound round the animal, without restricting respiratory and abdominal movements, to complete the holding of the patches, and the rabbit was placed in a restraining device for at least 4 h. Macroscopic observations were recorded at 1, 24, 48 and 72 h for both after patch removal. Each treated area was scored for erythema and oedema using a numerical system (0-4 in each case according to severity) based on that described by Draize, Woodard & Calvery (1948). The scores obtained for erythema and oedema at both of the treated sites in all six animals at the two or more reading times were totaled. The sum obtained was then divided by the total number of readings to provide a mean score (never greater than 8) termed the primary irritation index (PCI). The following scale was used to interpret the results:

PCI below 0.5: non-irritant; 0.5-3: slightly irritant; 3-5: moderately irritant; 5-8: severely irritant

The primary cutaneous irritation index obtained in this study was 0.04, hence the substance was concluded to be non irritant to the skin.

 

Malinak et al, 1960:

The skin irritation potential of the sodium fluorosilicate was evaluated in a study conducted with New Zealand white rabbits. In this study, 4 rabbits (2 males and 2 females) were used. To prepare the skin, the fur on the back of each animal was shaved so that an area of smooth skin approximately 10 x 10 cm. was exposed. Application of the dry powder, and a saturated solution in cold water, to the intact skin produced no gross change in each of the four rabbits. Hence, based on the findings of this study, sodium fluorosilicate is considered to be not an skin irritant (Malinak et al, 1960).

 

Dooms-Goossens et al, 1984:

The potential of the substance to cause pustules on exposure was evaluated in a study conducted with rabbits. In this study, the rabbits with intact and stabbed skin were exposed to the substance at the concentrations of 1, 5, 10 and 25 % for 24 hours. The formation of pustules was recorded in the following observation period. However, the internationally accepted guidelines however do not recommend testing with stabbed/abraded skin. Exposure to stabbed/abraded skin is also rarely encountered scenario with workers or consumers. Hence, stabbed skin is considered an elevated testing condition and the results obtained with stabbed skin normally do not have to be taken into account for hazard assessment. Among the sites with intact skin, no pustules were reported with 1, 5 and 10 % concentrations, while with 25 % concentration, 2 out of 10 sites had developed pustules. Hence, taking into account the proportion of animals with positive findings, the substance was considered to be not irritating as per the CLP (Regulation EC No. 1272/2008) criteria. A case of pustules being seen in a worker after the exposure to foam rubber was reported by Dooms-Goossens et al, 1984. The authors suspected this being the result of sodium fluorosilicate, one of the ingredients of the foam rubber. However, the investigations through patch and scratch testing with sodium fluorosilicate ruled out the possibility of it being a sensitiser. Animal testing as discussed above, concluded sodium hexaflurosilicate may lead to development of pustules on a damaged skin. However, the testing with intact skin did not cause pustules, supporting the conclusion that sodium hexafluorosilicate is not an irritant to the skin as per the CLP (Regulation EC No. 1272/2008) criteria. Taking into consideration the above discussed information, it can be safely assumed that the sodium hexafluorosilicate is not an irritant to the skin. Hence, based on the principles of the read across, ammonium hexafluorosilicate was also considered to be not irritating to the skin.

 

Eye irritation:

Currently no studies are available which evaluate the eye irritation potential of ammonium hexafluorosilicate. However, literature discussing eye irritation potential of sodium hexafluorosilicate is available, which has been presented below:

 

Guillot et al, 1982:

The eye irritation potential of the sodium fluorosilicate was evaluated in this study. In the first phase, the test substance was instilled into the lower conjunctival cul-de-sac of one eye of each rabbit; the other eye constituted the control. The substance was instilled in a dose of 100 mg weighed on a Mettler balance, type PL 200 (d = 1 mg). Observations were recorded at 1 hour and 1, 2, 3 and 4 and 7 days after instillation and in cases where lesions persisted, also at later stages. As the test substance lead to irritancy more severe than that classified as slightly irritant in the first test, a second phase was carried out where the test substance was similarly instilled into another group of six rabbits, and the eyeball and related structures were rinsed 30 seconds after the instillation. As the material was still found to be irritant, a third test was run with rinsing after 4 sec. Approximately 20 ml of the rinsing solution, at about 20°C was applied to the test eye and to the control using a plastic wash-bottle. Excess liquid was removed with sterile gauze. In the test without rinsing, the lesions in the eye and related structures were so severe that correct reading was sometimes impossible. In these cases, two calculations were made to give a minimum value, based on the assumption that all the impossible readings were negative (= 0), and a maximum value, derived from assuming .the highest possible score for each of these readings. The irritation classification was determined from the second value. The animals treated in this phase were killed after Day 7 because of the severity of the lesions. Rinsing at 30 seconds, lead to the irritation remaining relatively significant, with corneal opacity persisting for at least the first few days following instillation. Rinsing 4 seconds after instillation further reduced the severity of findings. Based on the above findings, sodium fluorosilicate was classified to be extremely irritant according to AFNOR guideline and as severely irritant according to OECD guideline.

 

Malinak et al, 1960:

The potential of sodium fluorosilicate to cause irritation or corrosion in eyes was evaluated in this study conducted with New Zealand White rabbits. For the testing with intact eyes, the dry powdered form of sodium fluosilicate was sprinkled liberally into the undamaged eyes of 3 rabbits. Slight conjunctival injection was detected in 15 minutes and had cleared completely by 24 hours in two of the rabbits. An acute purulent conjunctivitis developed in one eye of the third rabbit; this healed spontaneously without scarring in 5 days. No other abnormalities of the eyes or lids could be detected grossly. To determine the effects on the damaged eye, a 1 cm superficial scratch was made across the cornea onto the sclera of the eyes of two rabbits. The compound was then liberally sprinkled into the eyes. Localized conjunctival injection was noticeable immediately, but the eyes were perfectly normal at 24 hours. Hence, taking into consideration the above results, sodium fluorosilicate can be considered to not lead to irritation in eyes. Further, sodium hexafluorosilicate has been investigated in a GLP-study available with ECHA (sodium hexafluorosilicate dossier registered under REACH), which concludes the substance to be non irritating to the eyes. However, taking the results described by Guillot et al, 1982 into consideration, sodium hexafluorosilicate and consequently, ammonium hexafluorosilicate are considered as the eye irritants.

Justification for classification or non-classification

As discussed above, ammonium hexafluorosilicate does not warrant classification for skin irritation, however it is to be classified as an eye irritant category 2 as per the CLP (Regulation EC No. 1272/2008) criteria.