(5) Fluoride. Fluoride, in drinking water, will help prevent dental caries in
growing children. When the concentration is optimum, no ill effects wiII result and
caries rate wiII be 60-65 percent below the rates in communities using water supplies
with Iittle or no fluoride. On the other hand, excessive amounts of fluoride in water
consumed during the period of calcification of the teeth (from several months up to
about 16 years of age) produces objectionable fluorosis (mottled teeth). The optimum
fluoride concentration for a given community depends on climatic conditions since the
amount of water consumed depends on the air temperature. Table 4-2 gives the
recommended control Iimits. Concentrations greater than two times the optimum values
in the table are grounds for rejection of the supply. The addition of fluoride (fluoridation)
to the water supply is recommended where the concentration is less than the lower
control Iimit. Other effects from excessively high fluoride intake include:
(a) Bone changes when water containing 8-20 mg/l is consumed daily
for 20 or more years
(b) Crippling fluorosis when 20 mg or more from all sources is
consumed daily for 20 or more years.
Death from a single dose of 2.250-4.500 mg (5-10 g sodium
Annual average maximum daiIy
Recommended control limits--
air temperature1 ( F)
Fluoride concentration in ppm (mg/l)
53.7 and below
Based on temperature data obtained for a minimum of 5 years.
Concentrations greater than 2 times the optimum values shall be grounds for
rejection of the supply.
Table 4-2. Recommended fluoride concentration in drinking water.
(6) Lead. Lead taken into the body can be seriously injurious to health,
even lethal, if taken in by either brief or prolonged exposure. Prolonged exposure to
relatively small quantities may result in serious illness or death. Lead taken into the
body in quantities in excess of certain relatively low "normal" Iimits is a cumulative
poison. Poisoning may result from an accumulation of lead absorbed by the body from
anyone or all four common sources: food, air (especially air contaminated by