Sodium fluoride

CHEMICAL SUBSTANCE IDENTIFICATION

Chemical name                 

Sodium fluoride

Synonyms                           

Florocid, Floridine [2]

IUPAC name

sodium fluoride [1]

CAS No

7681-49-4

REACH registration number

EC No

Molecular formula              

FNa or NaF [1,2]

Substance group/chemical family

Mono constituent substance/ Inorganic [1]

Appearance

Physical state

Odour

Form

Colour

Solid (100%), @  20°C and 1013 hPa

Odourless  [2]

Crystalline (33%), Powder (33%), Other (33%)

colourless or white [2]

USES AND HANDLING ISSUES

Relevant identified uses

This substance is used in the following products: textile treatment products and dyes, pH regulators and water treatment products, metal surface treatment products, metals, welding & soldering products and non-metal-surface treatment products. This substance has an industrial use resulting in manufacture of another substance (use of intermediates).

This substance is used for the manufacture of: chemicals, textile, leather or fur, fabricated metal products, metals and mineral products (e.g. plasters, cement).

This substance is used in the following activities or processes at workplace: transfer of chemicals, industrial spraying, treatment of articles by dipping and pouring, roller or brushing applications, mixing in open batch processes, calendering operations, potentially closed industrial processing with minerals/metals at elevated temperature (e.g. smelters, furnaces, refineries, coke ovens) and transfer of substance into small containers. [1]

Handling considerations

Prevention statements

When handling this substance: do not eat, drink or smoke when using this product; wear protective gloves and/or clothing, and eye and/or face protection as specified by manufacturer/supplier.

Response statements

In case of incident: If swallowed: immediately call a poison center or doctor/physician. If in eyes: rinse cautiously with water for several minutes. Remove contact lenses if present and easy to do – continue rinsing. If on skin: wash with soap and water. [1]

Store in a cool, dry, well-ventilated location. Separate from acids and alkalies. Aqueous solutions of sodium fluoride slowly decompose and become alkaline when stored in glass. Therefore, sodium fluoride solutions should be stored in tight, plastic containers, especially if the pH of the solution is less than 7.5. Sodium fluoride solutions and tablets should be stored at a temperature less than 40 °C, preferably between 15-30 °C; freezing of the solutions should be avoided. ELIMINATE all ignition sources (no smoking, flares, sparks or flames in immediate area). Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. DO NOT GET WATER INSIDE CONTAINERS [2]

PHYSICO-CHEMICAL PROPERTIES

Molecular weight                                  

41.988172 g/mol [2]

Bulk density/Specific gravity

2.8 g/cm³ [2]

pH

7.4 (Freshly prepared saturated solution) [2]

Particle size

EC

Melting/Freezing point

996 °C @ 101.325 kPa [1]

Boiling point

1 695 °C @ 101.325 kPa [1]

Flash point

[2]

Flammability

Not flammable [1]

Vapour density

Vapour pressure

0 mmHg [1]

Solubility in water

37.03 - 41.4 g/L @ 0 - 40 °C [1]

Solubility in organic solvents

Insoluble in alcohol [2]

Solubility in inorganic solvents

Hydrolysis

Ionicity in water

Surface tension

Dispersion properties

Explosiveness

Other properties

Stability and reactivity

Chemical stability

Reactivity hazards

Corrosivity

corrosive to aluminium [2]

Polimerization

Incompatibility with various substances

incompatible with calcium and magnesium salts. [2]

Special remarks on reactivity

Physical, chemical and biological coefficient

Koc

Kow

pKa

log Kp

Henry-constant

ENVIRONMENTAL FATE AND BEHAVIOUR

Artificial pollution sources

Release to the environment of this substance can occur from industrial use: as processing aid, as an intermediate step in further manufacturing of another substance (use of intermediates), formulation of mixtures and in the production of articles. [1]

From factories, processing fluorine containing ores, dusts may consist of sodium fluoride volatilized .../and/... Then condensed by cooler surrounding air. Leaves of plants may collect some of the dust. Extent of contamination will depend upon topography of surrounding terrain & especially direction of prevailing wind. [2]

General terrestrial fate

NaF is highly reactive and, once released into the environment, is unlikely to remain in its original form for any significant length of time. NaF will rapidly dissociate in aqueous conditions to form sodium and fluoride ions and will further be transformed in air, water, sediment and soil to a variety of other fluorine-containing compounds. [8]

General aquatic fate

NaF is highly reactive and, once released into the environment, is unlikely to remain in its original form for any significant length of time. NaF will rapidly dissociate in aqueous conditions to form sodium and fluoride ions and will further be transformed in air, water, sediment and soil to a variety of other fluorine-containing compounds. [8]

General atmospheric fate

NaF is highly reactive and, once released into the environment, is unlikely to remain in its original form for any significant length of time. NaF will rapidly dissociate in aqueous conditions to form sodium and fluoride ions and will further be transformed in air, water, sediment and soil to a variety of other fluorine-containing compounds. [8]

General persistence and degradability

Abiotic degradation and metabolites

Biodegradation and metabolites

No data are required. This endpoint is not relevant for an inorganic substance. [8]

Bioconcentration

A correlation between fluoride levels in earthworms and elevated soil fluoride levels from polluted sites has been demonstrated, however levels were due to the soil content of the worm gut.  The uptake of fluoride into plants from soil is low as a consequence of the low bioavailability of fluoride in the soil and that atmospheric uptake is generally the most important route of exposure. A relatively high rate of fluoride uptake is noted for grass species, and the consumption of fluoride containing plants may lead to elevated fluoride levels in animals and humans.  Fluoride accumulates in aquatic organisms predominantly in the exoskeleton of crustacea and in the skeleton of fish; no accumulation was reported for edible tissues. In the terrestrial environment, fluoride accumulates in the skeleton of vertebrates and invertebrates. [8]

Volatilization

Photolysis

Hydrolysis

NaF will rapidly dissociate in water at environmentally relevant pH to form sodium and fluoride ions. [8]

Soil adsorption and mobility

HF is unstable and will rapidly hydrolyse in the environment and react to form other fluorine-containing compounds. The behaviour of fluoride in water is dependent on pH and mineral content. Fluoride is deposited to sediment as insoluble complexes and is essentially immobile in soil due to its incorporation into insoluble complexes. Adsorption to the soil solid phase is stronger at slightly acidic pH values (5.5–6.5). Fluoride is not readily leached from soils. [8]

ENVIRONMENTAL CONCENTRATIONS

Measured data

Fluoride concentrations in ground-water fluctuate within wide limits e.g. from <1 to 25 mg or more per litre. ... In surface fresh fluoride content is usually low, 0.01-0.3 mg/l. ... Fluoride concentrations are higher in sea ... averaging 1.3 mg/l. ... /Fluoride/ [2]

ECOTOXICOLOGICAL INFORMATION

General adverse effects on ecosystem

Acute toxicity (LC50, EC50)

Aquatic systems

Sodium fluoride is not classified for environmental effects according to the CLP Regulation (EC) 1272/2008.

Sodium fluoride will rapidly and extensively dissociate in the environmnet to form its constituent ions: sodium and fluoride. The toxicity of the sodium ion is considered very low compared to the fluoride ion. The fluoride ion is of relatively higher toxicity and therefore it can be predicted that the effects of exposure to the substance at relevant concentrations will be due to the contribution of the fluoride ion. Water-soluble inorganic salts of fluoride will similarly exist in the aqueous environment as their constituent ions, and their toxicity at relevant concentrations and for non-toxic cations will be due to the contribution of fluoride. This is the case for sodium fluoride (water solubility 41300 mg/L) or potassium fluoride (920000 mg/L). It is noted that this read-across approach was also taken for the 2001 EU Risk Assessment Report for hydrogen fluoride. [8]

LC50: 51 mg/L (freshwater fish, 4 days)[1]

EC50 / LC50: 26 mg/L (freshwater invertebrates) [1]

EC50 / LC50: 10.5 mg/L (marine invertebrates) [1]

EC50: 43 mg/L (freshwater algae, 4 days) [1]

EC50: 81 mg/L (marine water algae, 4 days) [1]

Terrestrial systems

Chronic toxicity (NOEC, LOEC)

Aquatic systems

EC10 / LC10 or NOEC:  4 mg/L (freshwater fish,  21 days) [1]

EC10 / LC10 or NOEC: 8.9 mg/L (freshwater invertebrates, 21 days) [1]

EC10 or NOEC: 50 mg/L (freshwater algae) [1]

EC10 or NOEC: 50 mg/L (marine water algae) [1]

NOEC (72 h) 101 mg/L (microorganisms) [1]

NOEC (48 h) 83 - 180 mg/L (microorganisms) [1]

NOEC (20 h) 7.1 mg/L (microorganisms) [1]

NOEC (16 h) 231 mg/L (microorganisms) [1]

Terrestrial systems

EC10 / LC10 / NOEC: 1.2 g/kg soil dw (terrestrial macroorganisms except arthropods, 5.133 months) [1]

EC10 / NOEC: 106 mg/kg soil dw (soil microorganisms, 63 days) [1]

HUMAN HEALTH EFFECTS and PROTECTION

Routes of human exposures

inhalation, ingestion, skin and/or eye contact [2]

General effects

Cough. Sore throat. Eye Redness. Pain. Abdominal pain. Burning sensation. Convulsions. Drowsiness. Cough. Diarrhoea. Sore throat. Vomiting. Unconsciousness. [2]

Endocrine disruption

Mutagenicity

While both positive and negative results have been reported in vitro, the reliable in-vivo studies indicate that fluoride salts do not interact directly with DNA and are not genotoxic when administered by an appropriate route of exposure. No classification is proposed.  [8]

Carcinogenicity

As noted in several reviews including the EU risk assessment report (RAR), the data from carcinogenicity studies are predominately negative with the slight increased incidence of osteosarcomas observed in male rats in the NTP study considered to be inconclusive and not sufficient to suggest fluoride salts would be carcinogenic. No classification is proposed. [8]

Reprotoxicity

No adverse effects on reproduction or development were observed in rat or rabbit teratology studies or in a 3 generation study in mice. No classification is proposed. [8]

Teratogenicity

No adverse effects on reproduction or development were observed in rat or rabbit teratology studies or in a 3 generation study in mice. No classification is proposed. [8]

Skin, eye and respiratory irritations

Skin: No adverse effect observed (not irritating) [1]

Classification is not required because sodium fluoride was not a skin sensitizer in guinea pigs when evaulated by the Buehler method. [8]

Eye: Adverse effect observed (irritating) [1]

Dust inhalation and skin or eye contact may cause irritation of the skin, eyes or respiratory tract [2]

Metabolism:

absorption, distribution & excretion

Exposure limits

DNEL: 2.5 mg/m³ (workers, inhalation, acute/short term, systemic effects, repeated dose toxicity) [1]

DNEL: 2.5 mg/m³ (workers, inhalation, long term, local effects, repeated dose toxicity) [1]

Drinking water MAC

Other information

NaF induced both blood cellular and humoral immune function in mice. [3]

Studies with sodium fluoride (NaF) dosing have indicated that F can damage human lymphocyte chromosomes [4], induce adverse effects in the spleen [5], inhibit growth and general health in rabbits and increase their nonspecific immune-related acid phosphatase and lysozyme activities [6].

F exposure exerts a complex and relevant effect on Treg cells in humans. [7]

Animal toxicity data

Acute toxicity (LD50)

LC50: 25 - 2 000 mg/kg bw (rat, oral)  [1]

Chronic toxicity (NOEL, LOEL)

NOAEL (rat): 25 mg/kg bw/day (oral, repeated dose toxicity) [1]

NOAEL (rat): 25 ppm (oral, repeated dose toxicity) [1]

LOAEL (rat): 4 mg/kg bw/day (oral, repeated dose toxicity) [1]

ENVIRONMENTAL STANDARDS AND REGULATIONS

Danger! According to the harmonised classification and labelling (CLP00) approved by the European Union, this substance is toxic if swallowed, causes serious eye irritation and causes skin irritation. [1]

According to REACH registrations:

H315: Causes skin irritation. H319: Causes serious eye irritation. H301: Toxic if swallowed. [1]

According to CLP notifications:

H315: Causes skin irritation. H319: Causes serious eye irritation. H301: Toxic if swallowed. H372: Causes damage to organs through prolonged or repeated exposure. [1]

EINECS regulation

̵listed on EINECS (European INventory of Existing Commercial chemical Substances) List [1]

OSHA regulations etc.

OTHER INFORMATION, SPECIAL REMARKS

Classification and proposed labelling with regard to toxicological data

CREATED, LAST UPDATE

Created

2019. 12. 11

Last update

2020. 09. 25

REFERENCES

[1] ECHA, Sodium fluoride, https://echa.europa.eu/hu/brief-profile/-/briefprofile/100.028.789, Accessed 2019. 12. 11

[2] Pubchem, Sodium fluoride, https://pubchem.ncbi.nlm.nih.gov/compound/Sodium-fluoride, Accessed 2019. 12. 12

[3] Guo, H., Kuang, P., Luo, Q., Cui, H., Deng, H., Liu, H., Lu, Y., Fang, J., Zuo, Z., Deng, J., Li, Y., Wang, X., & Zhao, L. (2017). Effects of sodium fluoride on blood cellular and humoral immunity in mice. Oncotarget, 8(49), 85504–85515. https://doi.org/10.18632/oncotarget.20198, Accessed 2020. 09. 23

[4] Albanese R, Sodium fluoride and chromosome damage (in vitro human lymphocyte and in vivo micronucleus assays). Mutagenesis. 1987; 2: 497-499.

[5] Podder S, Chattopadhyay A, Bhattacharya S, et al., Histopathology and cell alteration in the spleen of mice from low and high doses of sodium fluoride. Fluoride. 2010; 43: 237-245.

[6] Zhou BH, Wang HW, Wang JM, et al., Effects of malnutrition and supplemented nutrition on nonspecific immune function changes induced by fluoride in rabbits. Fluoride. 2007; 40: 169-177.

[7] Berenice Hernández-Castro, Mónica Vigna-Pérez, Lesly Doníz-Padilla, María D. Ortiz-Pérez, Esther Jiménez-Capdeville, Roberto González-Amaro & Lourdes Baranda (2011) Effect of fluoride exposure on different immune parameters in humans, Immunopharmacology and Immunotoxicology, 33:1, 169-177, DOI: 10.3109/08923973.2010.491081

[8] ECHA, Registered Dossier, NaF_https://echa.europa.eu/hu/registration-dossier/-/registered-dossier/14274/5/2/1 Accessed 2020. 09. 25