Compounds such as sodium and calcium fluoride are usually found as white solids. Sodium fluoride dissolves easily in water while calcium fluoride does not. Another compound is hydrofluorosilicic acid which can combine with sodium and potassium to form salts called fluorosilicates or silicofluorides.
Sodium fluoride is used in the controlled fluoridation of drinking-water, as a preservative in glues, in glass and enamel production, as a flux in steel and aluminium production, as an insecticide and as a wood preservative. Mouth rinses also have fluorides added to prevent tooth decay. Fluorides are also used in making ceramics, lubricants, dyes, plastics, and pesticides. Some skin medicines and cancer treatment drugs also contain fluorides.
Fluorides are released into the environment naturally through the weathering and dissolution of minerals, in emissions from volcanoes and in marine aerosols. Most releases of inorganic fluorides into the environment are from anthropogenic sources. They are released into the environment via coal combustion and process waters and waste from various industrial processes, including steel manufacture, primary aluminium, copper and nickel production, phosphate ore processing, fertiliser production and use, glass, brick and ceramic manufacturing, and glue and adhesive production. The use of fluoride-containing pesticides as well as the controlled fluoridation of drinking-water supplies also contributes to the release of fluorides from anthropogenic sources.
Impacts on human health and environment
Excessive exposure to fluorides may affect the bone, digestive system, eye, heart, lung, reproductive system, skin, teeth and throat.
Fluorides are found throughout the environment at very low levels. In areas where levels are higher, for example, due to emissions into the atmosphere, harmful effects can occur due to bioaccumulation leading to toxicity in animals and harm to vegetation. Fluorides accumulate in the bone tissue of terrestrial vertebrates, depending on factors such as diet and the proximity of fluoride emission sources. They also accumulate in aquatic organisms directly from the water or to a lesser extent via food.
Emission to water reporting threshold: 2000 kg/year
Data source: European Pollutant Emission Register