“…The median content of fluoride in water from all other aquifers is less than 1.5 ppm; however, many individual analyses show more than 1.5 ppm of fluoride, and water from one spring in the Lexington group contained 15 ppm of fluoride. It has been shown (Maier, 1950) that about 1 ppm of fluoride in water is sufficient to decrease the incidence of dental caries (decay of teeth) when the water is consumed by children whose teeth are developing. Fluorosis, or mottling of the tooth enamel, may become evident if, during the period of tooth development, the water consumed contains more than about 1.5 ppm of fluoride.…”