Ammonium hexafluorosilicate

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Sodium hexafluorosilicate did not induce mutations in the bacterial reverse mutation assay, hence using the principles of read across, ammonium hexafluorosilicate was also considered to be not mutagenic.

Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Refer chapter 13 for detailed read across justification.

Reason / purpose for cross-reference:

read-across: supporting information

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not examined

Positive controls validity:

not specified

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not examined

Positive controls validity:

not specified

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not examined

Positive controls validity:

not specified

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not examined

Positive controls validity:

not specified

Key result

Species / strain:

S. typhimurium TA 1538

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not examined

Positive controls validity:

not specified

Conclusions:

Sodium hexafluorosilicate was found to have no mutagenic potential in the bacterial reverse mutation assay.

Executive summary:

Currently no study is available on Ammonium hexafluorosilicate. However a similar substance Sodium hexafluorosilicate was evaluated for the mutagenic potential in a bacterial reverse mutation assay. This method is similar or equivalent to OECD test guideline 471. 5 tester strains of Salmonella typhimurium designated TA1535, TA100, TA1538, TA98 and TA1537, provided by Dr. B.N. Ames, University of California, Berkeley, CA (U.S.A.); were used. Two 1535 strains with different histories, TA1535 A obtained in 1973 and TA1535 B obtained in 1977, were also used for the testing. Tests were performed using 5 doses, up to 3600 µg/plate, in all 5 strains with and without activation by the S9 liver fraction from Aroclor-pretreated rats. No reverse mutations were observed with any of the tested strains. Hence, sodium hexafluorosilicate can be considered to be not mutagenic in this bacterial reverse mutation assay.

Reference 2

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Publication date - 11 May 1981

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

not specified

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

Name: Sodium hexafluorosilicate

Target gene:

Histidine auxotrophic strains of S. typhimurium

Species / strain / cell type:

S. typhimurium, other: TA1535, TA100, TA1538, TA98 and TA1537

Details on mammalian cell type (if applicable):

provided by Dr. B.N. Ames, University of California, Berkeley, CA (U.S.A.). Two 1535 strains with different histories were used: TA1535 A obtained in 1973 and TA1535 B obtained in 1977.

Metabolic activation:

with and without

Metabolic activation system:

S9 liver fraction from Aroclor-pretreated rats.

Test concentrations with justification for top dose:

5 doses, up to 3600 µg/plate

Details on test system and experimental conditions:

The substance was tested on 2 slightly different minimal media: one (in the following named ZLM medium) is a modified minimal medium for E. coli , and the other is the Vogel-Bonner (VB) medium. ZLM medium contained (in g/l): tri-sodium citrate. 2H20 (0.82), K2HPO4-3H20 (4.60), KH2PO 4 (1.50), (NH4)2SO 4 (1.00), MgSO4.7H20 (0.10) and glucose (17.0). The concentration of citrate was 3.5 times higher in VB medium than in ZLM medium. The concentrations of the other ions are up to 2-fold higher in VB medium.

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not examined

Positive controls validity:

not specified

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not examined

Positive controls validity:

not specified

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not examined

Positive controls validity:

not specified

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not examined

Positive controls validity:

not specified

Key result

Species / strain:

S. typhimurium TA 1538

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not examined

Positive controls validity:

not specified

Conclusions:

Sodium hexafluorosilicate was found to have no mutagenic potential in the bacterial reverse mutation assay.

Executive summary:

Sodium hexafluorosilicate was evaluated for the mutagenic potential in a bacterial reverse mutation assay. This method is similar or equivalent to OECD test guideline 471.

5 tester strains of Salmonella typhimurium designated TA1535, TA100, TA1538, TA98 and TA1537, provided by Dr. B.N. Ames, University of California, Berkeley, CA (U.S.A.); were used. Two 1535 strains with different histories, TA1535 A obtained in 1973 and TA1535 B obtained in 1977, were also used for the testing.

Tests were performed using 5 doses, up to 3600 µg/plate, in all 5 strains with and without activation by the S9 liver fraction from Aroclor-pretreated rats. No reverse mutations were observed with any of the tested strains. Hence, sodium hexafluorosilicate can be considered to be not mutagenic in this bacterial reverse mutation assay.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Description of key information

Sodium hexafluorosilicate did not induce mutations in the drosophila sex-linked recessive lethal assay nor it lead to micronucleus induction in the polychromatic erythrocytes of mice, hence using the principles of read across, ammonium hexafluorosilicate was also considered to be neither mutagenic nor clastogenic in vivo.

Link to relevant study records

Reference

Reference 1

Endpoint:

in vivo insect germ cell study: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Publication date - 11 May 1981.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 477 (Genetic Toxicology: Sex-linked Recessive Lethal Test in Drosophila melanogaster)

GLP compliance:

not specified

Type of assay:

Drosophila SLRL assay

Specific details on test material used for the study:

Test material was obtained from Fisher Scientific Co., Fair Lawn, NJ (U.S.A.);

Species:

Drosophila melanogaster

Strain:

other: The Berlin K (wild-type) and Basc strains were used.

Route of administration:

oral: feed

Vehicle:

2 % Tween 80

Details on exposure:

In Drosophila one dose close to the LD50 (0.25 mM) was applied by the adult feeding method in 5 % saccharose.

Dose / conc.:

0.25 other: mM

Dose / conc.:

42.02 other: mg

Remarks:

Dose was not specified in terms of 'per kg'

Key result

Sex:

not specified

Genotoxicity:

negative

Toxicity:

not specified

Vehicle controls validity:

not specified

Negative controls validity:

not specified

Positive controls validity:

not specified

Additional information on results:

Of the tested chromosomes, only a small portion (brood 1: 3 out of 1226, brood 2: 1 out of 1212 and brood 3: 2 out of 1236) were confirmed as sex-linked recessive lethals.

Conclusions:

Sodium hexafluorosilicate did not induce mutations/was not mutagenic in the Drosophila sex-linked recessive lethal assay.

Executive summary:

Sodium hexafluorosilicate was evaluated for the potential to induce mutations in a Drosophila melanogaster sex linked recessive lethal assay. Drosophila melanogaster strains: Berlin K (wild-type) and Basc, were used. In the tested Drosophila, one dose close to the LD50 (0.25 mM or 42.02 mg) was applied by the adult feeding method in 5 % saccharose. About 1200 X-chromosomes (brood 1: 1226, brood 2: 1212 and brood 3: 1236) were tested per experiment in each of 3 successive broods (3-3-4 days). In repeat experiments, sometimes only single broods were tested. F: progeny cultures with 2 or fewer wild-type males were routinely retested in the F3 generation to confirm X-linked recessive lethal mutations (RLs). Mosaics were not counted. "Clusters" of 2 were included because their occurrence was compatible with statistical expectation of independent origin. Of the tested chromosomes, only a small portion (brood 1: 3 out of 1226, brood 2: 1 out of 1212 and brood 3: 2 out of 1236) were confirmed as sex-linked recessive lethals. Hence based on the above findings, it can be concluded that sodium hexafluorosilicate did not induce mutations/was not mutagenic in the Drosophila sex-linked recessive lethal assay.

Reference 2

Endpoint:

in vivo insect germ cell study: gene mutation

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Refer chapter 13 for detailed read across justification.

Reason / purpose for cross-reference:

read-across source

Key result

Sex:

not specified

Genotoxicity:

negative

Toxicity:

not specified

Vehicle controls validity:

not specified

Negative controls validity:

not specified

Positive controls validity:

not specified

Conclusions:

Sodium hexafluorosilicate did not induce mutations/was not mutagenic in the Drosophila sex-linked recessive lethal assay.

Executive summary:

Currently no study is available on Ammonium hexafluorosilicate. However a similar substance Sodium hexafluorosilicate was evaluated for the potential to induce mutations in a Drosophila melanogaster sex linked recessive lethal assay. Drosophila melanogaster strains: Berlin K (wild-type) and Basc, were used. In the tested Drosophila, one dose close to the LD50 (0.25 mM or 42.02 mg) was applied by the adult feeding method in 5% saccharose. About 1200 X-chromosomes (brood 1: 1226, brood 2: 1212 and brood 3: 1236) were tested per experiment in each of 3 successive broods (3-3-4 days). In repeated experiments, sometimes only single broods were tested. F: progeny cultures with 2 or fewer wild-type males were routinely retested in the F3 generation to confirm X-linked recessive lethal mutations (RLs). Mosaics were not counted. "Clusters" of 2 were included because their occurrence was compatible with statistical expectation of independent origin. Of the tested chromosomes, only a small portion (brood 1: 3 out of 1226, brood 2: 1 out of 1212 and brood 3: 2 out of 1236) were confirmed as sex-linked recessive lethals. Hence, based on the above findings, it can be concluded that sodium hexafluorosilicate did not induce mutations/was not mutagenic in the Drosophila sex-linked recessive lethal assay.

Reference 3

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Study completion date - 11 May 1981.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Deviations:

not specified

GLP compliance:

not specified

Type of assay:

other: in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Specific details on test material used for the study:

Test material was obtained from Fisher Scientific Co., Fair Lawn, NJ (U.S.A.);

Species:

mouse

Strain:

NMRI

Sex:

male/female

Details on test animals or test system and environmental conditions:

Male and female mice (NMRI) and were obtained from S. Ivanovas GmbH and Co., Kisslegg/Allgau (Germany), and given standard chow (Altromin GmbH, Lage, Germany) and water ad libitum.

Route of administration:

intraperitoneal

Vehicle:

2 % Tween 80

Details on exposure:

The animals were treated at 0 and 24 h

Dose / conc.:

37.6 mg/kg bw/day

No. of animals per sex per dose:

4 mice (2 male, 2 female) per dose

Control animals:

yes, concurrent vehicle

Tissues and cell types examined:

micronucleated polychromatic erythrocytes

Details of tissue and slide preparation:

Slides were coded, and 1000 polychromatic erythrocytes were scored per mouse.

Statistics:

Significance was calculated according to the Kastenbaum-Bowman tables.

Key result

Sex:

male/female

Genotoxicity:

negative

Toxicity:

not specified

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

not specified

Additional information on results:

In the only group treated with sodium hexafluorosilicate (37.6 mg/kg bw/day), the micronuleated polychromatic erythrocytes were found to be at 2 %, while in the group treated with vehicle (2 % Tween 80), the micronucleated polychromatic erythrocytes were found at 2.2 %.

Conclusions:

Sodium hexafluorosilicate did not induce micronuclei when administered to the mice intraperitoneally. Hence, it is devoid of clastogenic potential.

Executive summary:

The clastogenic potential of sodium hexafluorosilicate was evaluated in a micronucleus assay conducted with NMRI mice. This study was conducted according to method equivalent or similar to OECD test guideline 474. In this assay, two groups of 2 males and 2 females received the test substance at 0 and 37.6 mg/kg bw/day via intraperitoneal administration. The animals were treated at 0 and 24 h, and bone-marrow smears were prepared at 30 h. Slides were coded, and 1000 polychromatic erythrocytes were scored per mouse. Significance was calculated according to the Kastenbaum-Bowman tables. In the only group treated with sodium hexafluorosilicate (37.6 mg/kg bw/day), the micronuleated polychromatic erythrocytes were found to be at 2 %, while in the group treated with vehicle (2 % Tween 80), the micronucleated polychromatic erythrocytes were found at 2.2 %. Hence based on the above findings, it was concluded that sodium hexafluorosilicate did not induce micronuclei when administered to the mice intraperitoneally. Hence, it is devoid of clastogenic potential.

Reference 4

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Refer chapter 13 for detailed read across justification.

Reason / purpose for cross-reference:

read-across source

Key result

Sex:

male/female

Genotoxicity:

negative

Toxicity:

not specified

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

not specified

Conclusions:

Sodium hexafluorosilicate did not induce micronuclei when administered to the mice intraperitoneally. Hence, it is devoid of clastogenic potential.

Executive summary:

The clastogenic potential of sodium hexafluorosilicate was evaluated in a micronucleus assay conducted with NMRI mice. In this assay, two groups of 2 males and 2 females received the test substance at 0 and 37.6 mg/kg bw/day via intraperitoneal administration. The animals were treated at 0 and 24 h, and bone-marrow smears were prepared at 30 h. Slides were coded, and 1000 polychromatic erythrocytes were scored per mouse. Significance was calculated according to the Kastenbaum-Bowman tables. In the only group treated with sodium hexafluorosilicate (37.6 mg/kg bw/day), the micronuleated polychromatic erythrocytes were found to be at 2 %, while in the group treated with vehicle (2 % Tween 80), the micronucleated polychromatic erythrocytes were found at 2.2 %. Hence based on the above findings, it was concluded that sodium hexafluorosilicate did not induce micronuclei when administered to the mice intraperitoneally. Hence, it is devoid of clastogenic potential.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Currently, no studies evaluating genetic toxicity potential of the ammonium hexafluorosilicate are available. The hexafluorosilicates disassociate into hexafluorosilicate ion and corresponding cation when in water (NTP, 2001; NICNAS, 2017). Hence, the genotoxicity of ammonium hexafluorosilicate has been discussed in terms of data available with hexafluorosilicates (i.e. sodium hexafluorosilicate) and ammonium ion.

 

Genotoxicity of hexafluorosilicates:

Sodium hexafluorosilicate has been evaluated in a bacterial reverse mutation assay, a drosophila sex linked recessive lethal assay and a micronucleus assay by Gocke et al. in 1981.

 

Bacterial reverse mutation assay:

A read across substance, Sodium hexafluorosilicate was evaluated for the mutagenic potential in a bacterial reverse mutation assay using S. typhimurium. 5 tester strains of Salmonella typhimurium designated TA1535, TA100, TA1538, TA98 and TA1537, provided by Dr. B.N. Ames, University of California, Berkeley, CA (U.S.A.); were used. Two 1535 strains with different histories, TA1535 A obtained in 1973 and TA1535 B obtained in 1977, were also used for the testing. Tests were performed using 5 doses, up to 3600 µg/plate, in all 5 strains with and without activation by the S9 liver fraction from Aroclor-pretreated rats. No reverse mutations were observed with any of the tested strains. Hence, sodium hexafluorosilicate can be considered to be not mutagenic in this bacterial reverse mutation assay.

 

Drosophila sex linked recessive lethal assay:

Sodium hexafluorosilicate was evaluated for the potential to induce mutations in a Drosophila melanogaster sex linked recessive lethal assay. Drosophila melanogaster strains: Berlin K (wild-type) and Basc, were used. In the tested Drosophila, one dose close to the LD50 (0.25 mM or 42.02 mg) was applied by the adult feeding method in 5 % saccharose. About 1200 X-chromosomes (brood 1: 1226, brood 2: 1212 and brood 3: 1236) were tested per experiment in each of 3 successive broods (3-3-4 days). In repeat experiments, sometimes only single broods were tested. F: progeny cultures with 2 or fewer wild-type males were routinely retested in the F3 generation to confirm X-linked recessive lethal mutations (RLs). Mosaics were not counted. "Clusters" of 2 were included because their occurrence was compatible with statistical expectation of independent origin. Of the tested chromosomes, only a small portion (brood 1: 3 out of 1226, brood 2: 1 out of 1212 and brood 3: 2 out of 1236) were confirmed as sex-linked recessive lethals. Hence based on the above findings, it can be concluded that sodium hexafluorosilicate did not induce mutations/was not mutagenic in the Drosophila sex linked recessive lethal assay.

 

Micronucleus assay:

The clastogenic potential of sodium hexafluorosilicate was evaluated in a micronucleus assay conducted with NMRI mice. In this assay, two groups of 2 males and 2 females received the test substance at 0 and 37.6 mg/kg bw/day via intraperitoneal administration. The animals were treated at 0 and 24 h, and bone-marrow smears were prepared at 30 h. Slides were coded, and 1000 polychromatic erythrocytes were scored per mouse. Significance was calculated according to the Kastenbaum-Bowman tables. In the only group treated with sodium hexafluorosilicate (37.6 mg/kg bw/day), the micronucleated polychromatic erythrocytes were found to be at 2 %, while in the group treated with vehicle (2 % Tween 80), the micronucleated polychromatic erythrocytes were found at 2.2 %. Hence based on the above findings, it was concluded that sodium hexafluorosilicate did not induce micronuclei when administered to the mice intraperitoneally. Hence, it is devoid of clastogenic potential. Based on the above information, it can be concluded that sodium hexafluorosilicate is neither mutagenic nor clastogenic, and hence not genotoxic.

 

Ammonium ion and genotoxicity:

Ammonium ion and several ammonium salts (ammonium ion once in an aqueous solution, can exist in combination with a variety of anions as ammonium salts) are essential for proper physiological functioning in mammals (and humans). The ammonium ion is required in acid-base balance and in intermediary metabolic cycles. Ammonia is produced in the human body by the deamination of amino acids as well as amides. Ammonia is also normally produced in the brain and muscles (SCOGS-34, FDA, 1974). The genotoxicity of ammonium chloride has been discussed in a SIDS Initial Assessment Report for SIAM 17 (OECD SIDS-ammonium chloride, 2003). It was reported to have a negative outcome in a reverse mutation study in bacteria [OECD TG 471, GLP, Hoechst AG, 1987]. Ammonium chloride was found to be clastogenic in an in vitro chromosomal aberration test with Chinese hamster lung cells (CHL/IU) without metabolic activation, however the result is ascribed to the acidity of the substance (osmotic effects rather than a direct interaction with DNA) (Ishidate et al.,1984). However, it did not lead to clastogenic effects in an in vivo micronucleus assay up to the maximum tolerance dose. Based on the above information, the assessment concluded that ammonium chloride should be considered to be not genotoxic [Hayashi et al., 1988]. In addition to these studies, the currently registered dossier for ammonium chloride with ECHA, also lists ammonium chloride to be negative in a bacterial reverse mutation assay (Ishidate et al., 1984) and supports the conclusion that ammonium chloride is not genotoxic. The SIDS Initial Assessment Report for SIAM 24, (OECD SIDS- ammonia, 2007) reports that ammonia, ammonium thiosulfate and the analogues ammonium sulfate and diammonium phosphate (DAP) did not induce effects in tests on gene mutations and chromosomal aberrations. Considering, the negative results obtained in the micronucleus assay with ammonium chloride [Hayashi et al., 1988], the assessment report concludes ammonia and the salts assessed to be not genotoxic. Similarly, currently available dossiers for ammonia anhydrous, ammonium fluoride and ammonium nitrate with ECHA also conclude the substances being not genotoxic. The scientific opinion by EFSA [Opinion Flavouring Group Evaluation 46 (FGE.46)1: Ammonia and two ammonium salts from chemical group 30, EFSA-Q-2008-050, 2008], in addition to the results mentioned above, also discusses a micronucleus assay where a single intraperitoneal dose of ammonium at 12, 25 or 50 mg/kg bw lead to dose-dependent increases in the frequencies of micronuclei when compared to controls (Yadav & Kaushik, 1997). However, in absence of details concluded that no conclusions can be drawn. This assessment also discusses slight mutagenic activity being reported in Drosophila following exposure to ammonia gas, but only at very toxic levels (US ATSDR, 2004). However, taking into account the negative results as discussed above, the ammonia and salts were considered to be devoid of genotoxic potential.

 

Conclusion:

As discussed above neither the ammonium ion and its salts nor the sodium hexafluorosilicate can be considered genotoxic. Thereby supporting the conclusion that ammonium hexafluorosilicate is not genotoxic.

Justification for classification or non-classification

Based on the above discussion, ammonium hexafluorosilicate was not considered genotoxic and hence does not require classification as per the CLP (Regulation EC No.1272/2008) criteria.