FRANKLIN — Parents at the Cave Hill School in Franklin received notification yesterday that there were elevated fluoride levels in the school’s water.
Regional School Unit 24 (RSU 24) Business Manager David Bridgham, however, said that the matter is mostly a precautionary one.
“This is not anything new. We’ve had a treatment system in place for years,” Bridgham said. “We use a treatment process called de-ionization. There’s a resin similar to rock salt that’s placed in a tank, and the water that comes into the building flows through that tank. There’s a chemical reaction that removes the fluoride from the water.”
The Environmental Protection Agency’s current maximum allowable amount of fluoride in public drinking systems is 4 milligrams per liter (mg/L). The water provided by the school currently has a fluoride concentration of 3.4 mg/L.
“Anytime we go above 2 mg/L, we’ll backwash the system, maybe add some more resin to bring the fluoride levels down,” Bridgham said. “That water has to have a pretty high concentration of fluoride, because it’s normally around 1.4-1.6 mg/L.”
High concentrations of fluoride can cause cosmetic discoloration of permanent teeth in children under the age of 9.
“There’s naturally occurring fluoride in the bedrock around the school,” Bridgham said. “And at plenty of houses. This notification is just going out because it’s important to keep people informed.”