Fluoride compounds: Sources of emissions

Description

Hydrogen fluoride is used to make aluminum, chloroflurocarbons (CFCs), aluminum fluoride, sodium fluoride and other fluoride salts. It is used in the petroleum, chemical, and plastics industries. It is used to separate uranium isotopes. It is used to clean metals, bricks, or remove sand from metal castings. It is used to etch glass and enamel, polish glass and galvanize iron. It is used in brewing and to cloud light bulbs.

Substance details

Substance name: Fluoride compounds

CASR number: Not applicable

Molecular formula: Fluoride: F-
Hydrofluoric acid: HF
Sodium Fluoride: NaF

Synonyms: Fluoride: CASR # 16984-48-8; 
Hydrogen Fluoride (Hydrofluoric Acid): CASR # 7664-39-3; 
Sodium Fluoride: CASR # 7681-49-4

Physical properties

Melting Point: Hydrogen Fluoride -83.55°C
Sodium Fluoride: 993°C

Boiling Point: Hydrogen Fluoride: 19.5°C
Sodium Fluoride: 1700°C

Vapour Density: Hydrogen Fluoride: 0.15
Sodium Fluoride: – (solid)

Specific Gravity: Hydrogen Fluoride: 0.993
Sodium Fluoride: 2.558

Chemical properties

Fluoride compounds are all related by containing fluorine. Fluorine is a naturally occurring element in the earth. It is usually found in the form of the mineral flourspar, CaF2. Fluorine is a yellow-green gas with a strong, sharp odour (like pool chlorine). It combines with hydrogen to make hydrogen fluoride, a colourless gas with a strong irritating odour. Hydrogen fluoride dissolves in water to make hydrofluoric acid. Hydrogen fluoride will corrode most substances except lead, wax, polyethylene, and platinum. Hydrogen fluoride is used to manufacture other fluorine-based chemicals including Sodium fluoride, which is a white powder, although sometimes it is dyed blue for identification purposes.

Further information

The National Pollutant Inventory (NPI) holds data for all sources of fluoride compounds emissions in Australia.

Description

Fluorides are everywhere throughout the environment, but at very low levels that are not believed to be harmful. Small amounts of sodium fluoride help prevent tooth decay, but high levels may harm your health. In children whose teeth are forming, excessive fluoride levels may cause dental fluorosis with visible changes in the teeth. In adults, high fluoride over a long time may lead to skeletal fluorosis with denser bones, joint pain, and limited joint movement. This is rare. High levels of fluorine or hydrogen fluoride gas can cause muscle spasms, harm the lungs and heart and cause death. At low levels they can irritate the eyes, skin and lungs. Contact with hydrofluoric acid (even diluted) can burn the eyes (causing blindness) and skin, causing severe burns deep beneath the skin damaging internal tissues. This can occur hours after contact, even if no pain is initially felt. Contact with hydrofluoric acid happens mainly in the workplace. Long-term exposures may damage the kidneys and liver.

Entering the body

Fluoride compounds may enter the body by inhaling or ingestion.

Exposure

Workers in the industries that use or produce fluoride compounds are at greatest risk of exposure. Consumers are most likely to be exposed to fluoride compounds when using consumer products containing fluoride compounds; especially toothpaste or fluoride enhanced water. Residents in close proximity to production and processing facilities using fluoride compounds may also receive very low levels of fluoride esposure.

Health guidelines

Worksafe Australia: 
For hydrogen fluoride the eight hour time weighted average (TWA) exposure limit is 2.6 mg/m3. Worksafe Australia reports this product causes severe burns, and is toxic by inhalation. For fluorine the eight hour time weighted average (TWA) exposure limit is 1.6 mg/m3.

Australian Drinking Water Guidelines (NHMRC and ARMCANZ, 1996):
Maximum of 1.5 mg/L (i.e. 0.0015 g/L).

Description

Hydrogen fluoride will exist as a particle in the air if released to the atmosphere. It dissolves when mixed with water. Insufficient data are available to predict the short-term or long term effects of hydrogen fluoride to aquatic life, plants, birds or land animals. Concentrated hydrogen fluoride is very corrosive and would badly burn any plants, birds or land animals exposed to it. The concentrations of hydrogen fluoride found in close proximity to sources may adversely affect some species of plants. Small quantities of hydrogen fluoride will be neutralised by the natural alkalinity in aquatic systems. Larger quantities may lower the pH for extended periods of time. Fluorides are not expected to bioaccumulate.

Entering the environment

Industrial emissions of fluoride compounds can produce elevated concentrations in the atmosphere. Hydrogen fluoride will exist as a particle, which may dissolve in clouds, fog, rain, dew, or snow. In clouds and moist air it will travel along the air currents until it is deposited as wet acid deposition (acid rain, acid fog, etc). In waterways it readily mixes with the water.

Where it ends up

Hydrogen fluoride may enter the air during production, use and transportation. The gas dissolves in clouds, fog, rain, or snow. This impacts the environment as wet acid deposition ('acid rain'). In the environment it will react with other chemicals present (ammonia, magnesium, calcium) to form salts, neutralising the acid.

Environmental guidelines

No national guidelines.

Industry sources

The primary sources of fluoride emissions are the industries that manufacture it or use it in production. Some of the industries that use it in production are aluminium industry, oil drilling and refining, the chemical and plastics industries, agricultural and pesticide chemical manufacturers, dye manufacturers, manufacturers of metal parts. These are emissions to the air unless there is a spill.

Diffuse sources, and industry sources included in diffuse emissions data

Other possible emitters of fluoride are metal cleaning operations, glass and enamel manufacturing and glazing, toothpaste, and fluoride enhanced water. These emissions may be to the soil, water, or air.

Natural sources

Fluorine is a naturally occurring element in the earth, but elemental fluorine is too reactive to be found in nature. Fluorine is found in nature as part of the mineral fluorspar. Water in rivers or streams that flow over rocks rich in fluorine-containing minerals such as fluorspar may naturally contain dissolved fluoride.

Transport sources

No known mobile sources.

Consumer products

Toothpaste, pesticides, ceramic and glass polishing etching and frosting materials, special dyes, drinking water in some areas may be naturally or artificially enriched in fluoride.

Sources used in preparing this information

  • Agency for Toxic Substances and Disease Registry (1993), ToxFAQS Fluorides, Hydrogen fluoride, and Fluorine (F) (accessed, May, 1999)
  • Australian and New Zealand Environment and Conservation Council (ANZECC) (1992) Australian Water Quality Guidelines for Fresh and Marine Waters
  • CalEPA Air Resources Board Toxic Air Contaminant Summary Hydrogen Fluoride (accessed, May, 1999)
  • Cornell University, Planning Design and Construction, MSDS, Hydrogen Fluoride (accessed, May, 1999)
  • Environmental Defense Fund (1998), Fluoride: The Chemical Scorecard: (accessed, May, 1999)
  • Environmental Defense Fund (1998), Sodium Fluoride: The Chemical Scorecard: (accessed, May, 1999)
  • Environmental Health Center, a division of the National Safety Council, Environment Writer – Chemical Backgrounders Hydrogen Fluoride (Hydrofluoric Acid) (HF) (July, 1997) (accessed, May, 1999)
  • Lange, A. (1946) Handbook of Chemistry, Handbook Publishers, Inc., Sandusky, Ohio, USA
  • National Environment Protection Council (1998a), National Environment Protection Measure for the National Pollutant Inventory (accessed, May, 1999)
  • National Health and Medical Research Council (NHMRC) and Agriculture and Resource Management Council of Australia and New Zealand (ARMCANZ) (1996) Australian Drinking Water Guidelines.
  • New Jersey Department of Health, Right to Know Program (1986), TRIFacts, Hydrogen Fluoride (accessed, May, 1999)
  • NTP Chemical Repository, Radian Corporation, Sodium Fluoride (AUGUST 29, 1991) (accessed, May, 1999)
  • Technical Advisory Panel (1999), Final Report to the National Environment Protection Council.
  • U.S. Department of Labor, Occupational Safety & Health Administration; OCCUPATIONAL SAFETY AND HEALTH GUIDELINE FOR Hydrogen Fluoride (September 1996) (accessed, May, 1999)
  • Worksafe Australia (1996), Exposure Standard Hydrogen Fluoride (as F) (accessed, May, 1999)
  • Worksafe Australia (1996), Hazardous Substance Hydrogen Fluoride (accessed, May, 1999)
  • Worksafe Australia (1996), Hazardous Substance Sodium fluoride (accessed, May, 1999)