Salt is being used by transportation officials to keep the East Coast of the United States clear of snow.
A growing body of research shows that pouring tons of salt on the roads can have damaging environmental and health consequences.
Salt washes into the soil, lakes and streams when snow and ice melt. The Environmental Protection Agency says that it has killed or is threatening to kill wildlife in freshwater environments.
Bill Hintz, an assistant professor in the environmental sciences department at the University of Toledo, is the lead author of a recent research review published in the journal Frontiers in Ecology and the Environment.
There is a lot of scientific evidence to suggest that freshwater is being contaminated by salt from the use of things like road salt beyond the concentration which is safe for freshwater organisms and for human consumption.
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. According to the Cary Institute of Ecosystem Studies in New York, more than 20 million metric tons of salt are poured on U.S. roads each winter.
Victoria Kelly, the environmental programming manager at the Cary Institute, said that there is little done to address the environmental impact of road salt because it is cheap and effective. Salt lowers the freezing temperature of water, which prevents snow from turning to ice.
Road salt is made from the same chemical as table salt. According to the U.S. Geological Survey, 43 percent of the salt consumed in the United States is used for highway de-icing.
The consequences of insufficiently salting roads were seen this week, when hundreds of drivers were stranded by a snowstorm on I-95 in Virginia. The storm began with rain, which washed away road salt, making it difficult to keep the roads clear. There was snow in the Mid-Atlantic States and the Northeast on Friday.
Environmentalists say the problems associated with road salt are getting harder to ignore. Ms. Kelly said that people on low-sodium diet were being harmed by the salt in drinking water.
A city worker threw salt from a truck.
A study of wells in the state of New York found that the levels of salt in the water were much higher than the state's recommendation for people on very low-sodium diet.
A study in the journal Environmental Science and Technology found that 24 percent of private drinking wells in New York were contaminated with salt that had been used on roads. According to the Centers for Disease Control and Prevention, about 15 percent of people in the United States get their water from private ground wells.
More states are rethinking the amount of salt they use because of the costs. The Adirondack Road Salt Reduction Task Force was established by the governor of New York.
Ms. Hochul said that the group of individuals would work to protect the state from the adverse effects of road salt. We are looking forward to seeing this group make progress in preventing further pollution to our environment.
There are consequences for animals. Dr. Hintz said his review showed that elevated salinity levels in the water had already caused a reduction in the growth of freshwater organisms and a reduction in their reproduction outputs.
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The Environmental Protection Agency estimates that road salt causes $5 billion in repairs in the United States every year. To help offset the effects of road salt and to limit driving when de-icing chemicals are at their highest concentrations, the AA suggests drivers wash and clean their vehicles regularly.
The Salt Association in Britain said that salt was the cheapest form of de-icing material and that it had a low environmental impact. There are environmental implications from winter road maintenance, according to the organization. Highway depots, spreading vehicles and the de-icing agent all contribute, but with good management, this burden can be minimized.
There are alternatives that can reduce salt usage without compromising driver safety.
The Cary Institute says that one way to reduce the amount of salt used is to brine roads before storms. Better salt storage sites can reduce waste.
Jefferson County, Wis., has already made changes. The highway commissioner said that the switch to a brine solution had enabled the county to cut its salt use by up to 60 percent. The county has reduced its winter maintenance costs by 20 percent by using less salt.
Over the past decade, some states, including Rhode Island, have passed legislation aimed to reduce their use of road salt, but environmentalists say more needs to be done.
Ms. Kelly said that engineers have developed better alternatives, but they have not been widely implemented because of the upfront costs.
She said that it will save us money and help to save our freshwater, but that it will take a long time to see the impact of the steps we take.
