Environmentally friendly additives to road salt may still have tradeoffs.
Every year, as winter closes in, transportation authorities prepare to deploy their vast stockpiles of salt and sand to keep the roads and highways safe and ice-free for drivers.
In the United States, roughly 18 million metric tons of road salt are spread on the roads each year, with another 5 million used in Canada. In Minnesota, nine tons of salt are applied per lane mile each winter – meaning a single mile of a four-lane highway gets 36 tons of salt dumped on it each year.
But all that salt does not just disappear along with the ice in the spring; it sticks around, and can have major effects on the surrounding ecosystems and even drinking water. Read more at Inside Science.