Water quality fact sheet: Fluoride

Fluoride has been found to have a significant
mitigating effect against dental caries and it is
accepted that some fluoride presence in drinking
water is beneficial. Optimal concentrations are
around 1 mg/l. However, chronic ingestion of
concentrations much greater than 1.5 mg/l (the
WHO guideline value) is linked with development
of dental fluorosis and, in extreme cases, skeletal
fluorosis. High doses have also been linked to
cancer. Health impacts from long-term use of
fluoride-bearing water have been summarised
(Dissanayake, 1991) as:
<0.5 mg/l:
dental caries
0.5-1.5 mg/l
promotes dental health
1.5-4 mg/l
dental fluorosis
>4 mg/l
dental, skeletal fluorosis
>10 mg/l
crippling fluorosis