Tap water is seen in this photo illustration in Washington, DC, on August 19, 2019. - A study published on August 19, 2019 links exposure to fluoridated tap water during pregnancy to lower IQ scores in infants, but several outside experts expressed concern over its methodology and questioned its findings. Fluoride has been added to community water supplies in industrial countries to prevent tooth decay since the 1950s. Very high levels of the mineral have been found to be toxic to the brain, though the concentrations seen in fluoridated tap water are generally deemed safe. (Photo by Alastair Pike / AFP) AFP / Alastair Pike
