All organisms are exposed to fluoride from natural and/or anthropogenic sources. Very high intakes have been observed in areas worldwide in which the environment is rich in fluoride and where groundwater high in fluoride is consumed by humans. Increased exposure might occur in the vicinity of point sources. Fluoride in dental products is an additional source for many people.
Fluoride has both beneficial and detrimental effects on human health, with a narrow range between the intakes at which these occur.
Effects on the teeth and skeleton may be observed at exposures below those associated with the development of other organ- or tissue-specific adverse health effects.
Effects on the bone (e.g., skeletal fluorosis and fracture) are considered the most relevant outcomes in assessing the adverse effects of long-term exposure of humans to fluoride.
Skeletal fluorosis is a crippling disability that has a major public health and socioeconomic impact, affecting millions of people in various regions of Africa, China and India.
Intake of fluoride in water and foodstuffs is the primary causative factor for endemic skeletal fluorosis. In some regions, the indoor burning of fluoride-rich coal also serves as an important source of fluoride.
There are few data from which to estimate total exposure to and the bioavailability of fluoride, and there are inconsistencies in reports on the characterization of its adverse effects.
There is clear evidence from India and China that skeletal fluorosis and an increased risk of bone fractures occur at a total intake of 14 mg fluoride/day and evidence suggestive of an increased risk of bone effects at total intakes above about 6 mg fluoride/day.
Excess exposure to bioavailable fluoride constitutes a risk to aquatic and terrestrial biota.
Fluoride-sensitive species can be used as sentinels for the identification of fluoride hazards to the environment.
There is a need to improve knowledge on the accumulation of fluoride in organisms and on how to monitor and control this.
The biological effects associated with fluoride exposure should be better characterized.