Salt has been used to de-ice roads in the United States since the 1930s, and its use across the country has tripled in the past 50 years, Dr. Hintz said. More than 20 million metric tons of salt are poured on U.S. roads each winter, according to an estimate by the Cary Institute of Ecosystem Studies in New York, and the environmental costs are growing....Road salt is made from sodium chloride, the same chemical found in table salt. Of all salt consumed in the United States, about 43 percent is used for highway de-icing, according to the U.S. Geological Survey in 2020.Ms. Kelly said the accumulation of salt in drinking water reservoirs in some places was harming people on low-sodium diets.A 2018 study of wells in Dutchess County, N.Y., found that sodium concentration in wells reached levels as high as 860 milligrams per liter — much higher than the federal and state recommendation that levels not exceed 20 milligrams per liter for people on very low-sodium diets and 270 milligrams per liter for people on moderately restricted sodium diets.
That's a lot of salt!