What is the concentration of fluoride in the water at schools located in areas with no community fluoridation and why?

• A. Equal to the community water supply.
• B. Higher due to school activity programs only.
• C. 4-5 times higher because children are at school only part of each day and year.
• D. Lower because schools rely on bottled water.

Answer: (C)

Fluoride exposure depends on both the concentration in the water and how much water a child consumes over time. When a population has no community water fluoridation, schools would need to compensate for the fact that children are at school only part of each day and only part of the year. To deliver a similar overall fluoride intake to what a fully fluoridated community would provide, the concentration of fluoride in school water would have to be higher, roughly four to five times higher, so that the time-weighted exposure during school hours adds up to the same annual amount. In other words, because the daily and yearly time children spend at school is limited, a higher school-water fluoride concentration is required to achieve comparable total intake.