The name fluorine was coined by André Ampère in 1812, long before the element was isolated. It was known that metal fluorides contained an element similar to chlorine, but even Sir Humphry Davy, a scientist responsible for the isolation of a number of elements, could not isolate it. Indeed, he became ill while trying due to the expose to the hydrofluoric acid. Finally, in 1886, the French chemist Henri Moissan was able to collect fluorine by electrolysis of potassium bifluoride.
Salts and minerals that contain fluorine are used mainly in the production of hydrogen fluoride. Concentrated fluoride is corrosive and can attack the skin, however. Fluoride ions occur naturally in minerals but are only present in small quantities in water. The most well-known fluoride compound is sodium fluoride, which is used commonly in toothpaste.
Healthy levels of fluoride vary for adults and children, with the US Department of Agriculture recommending a maximum daily intake of 10 mg for adults and between 0.7 ‐ 2.2 mg for younger children. Soluble fluoride salts, such as sodium fluoride already mentioned, are toxic in high quantities. The lethal dose for humans is estimated to be between 5 and 10 g.
Despite this, fluoride is regularly used in toothpaste at a safe level and is shown to prevent tooth decay, but it is advised that fluoride toothpaste is not swallowed after brushing. Tooth cavities are caused by bacteria, and this is shown to be linked to fluoride deficiencies in the diet.
Investigations into fluoridation of water began in 1901 by a dentist named Dr Frederick McKay. He noticed a staining of the teeth in Colorado residents and eventually linked the water supply as being responsible. His and other research that followed also found that this staining was correlated with lower decay rates. The cause of this was later found to be elevated levels of fluoride in the sites where this was occurring.
As well as appearing in water from natural sources, in some parts of the world fluoride is added to the water in a process known as fluoridation ‐ the US Centres for Disease Control described this as "one of the 10 most important public health advances of the 20th century". Many allegations are made linking fluoridation to a variety of conditions, but these claims do not carry substance. Many people regularly drink water that contains natural fluoride and do not observe any negative health effects. Water fluoridation is supported by the World Health Organisation, but public bodies such as this also place legal limits on the amount of fluoride that can appear in drinking water.
Fluoride in your drinking water can be detected by the following tests.
Fluoride can be reduced or removed from your drinking water using the following methods.
