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An occupational sentinel health event; cryolite workers (grinding room) and cryolite refining workers are at increased risk; [Mullan]; Cryolite (Na3AlF6) is a natural fluoride mined in Greenland, or it can be manufactured from fluorspar. A major use of cryolite is in the electrolytic reduction of alumina to produce aluminum. [Hawley] Skeletal fluorosis was first recognized in 1931 among workers processing cryolite. Patients may develop bony exostoses, calcified ligaments, kyphosis, and spinal stenosis. Crippling skeletal fluorosis has been reported in workers with fluoride exposures of 20-80 mg/day for 10-20 years. No skeletal changes were found in workers exposed to <8 mg/day for as long as 14 years. No adverse effects result from the 1-2 mg/day dose given in water fluoridation programs to prevent dental caries. The dental enamel becomes mottled at a dose of 2-4 mg/day. Increased fluoride in drinking water has been measured in regions of India, China, Africa, and South America. Environmental fluorosis has been detected in China caused by high-fluoride coal burned indoors. [Rosenstock, p. 543-5] Dental fluorosis has been reported after chronic exposures from drinking fluoride-contaminated water and mining fluorspar and cryolite ores. Recent evidence suggests that fluorosis may be reversible. [Rom, p. 1087] |
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