The levels of hysteria, quackery and pure rubbish generated around this ion compare with that from antivaccinationists.
We evolved around the Rift Valley in Africa, which has a high fluoride level in rocks and groundwater. Many other areas of the planet might be less suited to us, or vice versa. Low fluoride levels would be one of the easiest faults for terraforming to correct, but in the absence of this, use other means to keep human dietary intake optimal.
The 1994 WHO report stated that "the world optimum concentration would normally be in the range 0.5 – 1.0 mg/l"...in the water supply. UK recommendation is 0.7-1.2mg/l for optimal prevention of dental caries. In terms of a mild adverse effect (dental fluorosis in children) this leaves us with a relatively low therapeutic index, so it is reasonable to expect careful additive control, say to water supplies.
Natural water supplies can have excess fluoride. Also accidents have occurred. This allows fair confidence in these estimates for exposure to fluoride to be excessive:
- ≥ 2mg/l drinking water child dental fluorosis
- ≥ 8mg/l drinking water skeletal fluorosis
- ≥ 50mg/l drinking water (for 12hours) gastroenteritis
- 5-20 mg/m3 air (occupational) leads to crippling fluorosis
- LD50 adults 2,500-10,000 mg of a fluoride salt (16 mg/kg in child)
- McDonagh M, Whiting P et al. A systematic review of public water fluoridation. York:The University of York NHS centre for reviews and dissemination. Report 18. 2000
This article is a stub. Please feel free to expand it and make it more encyclopaedic.