New device simplifies measurement of fluoride contamination in water
(PHYSorg.com Chemistry)

Adding fluoride to water is common practice in a number of countries, including the U.S., Australia, Brazil, Malaysia, India and Vietnam. In low concentrations (below 1.5 mg/L), it can prevent tooth decay and even strengthen bones, but levels above that can have the opposite effect, causing serious dental and bone disease, especially in children and developing fetuses.