Road Salt Damages Ecology

Scientists know that road salt can kill trees and that white pines are particularly sensitive. Sometimes, road salt puts such a strain on native species that hardier invasive plants and animals take over.

The use of salt to melt snow and ice from slippery roads has an environmental downside that can affect a widespread area long after winter has passed, scientists say.

Road salt can affect amphibians in small seasonal wetlands called vernal pools located as far as 550 feet from roads. Salt can be responsible for changes in water chemistry many miles downriver from a road crossing. The effects can be seen all the way down to the ocean.

Nationwide, more than 13 million tons are applied annually, according to the federal Environmental Protection Agency, and road salt, which frequently contains dyes and other chemicals is affecting the environment. Researchers have learned that excess salt changes stream chemistry, causing certain minerals to leach out of soils. At high enough concentrations, salt can increase the acidity of water, causing some of the same negative effects as acid rain. Studies have shown that road salt attracts deer and moose, causing collisions with vehicles. Other scientists have learned that some amphibians refuse to cross salted roads and, as a result, can be separated from their traditional breeding areas, and high salt concentrations affected the ability of wood frogs and spotted salamanders to survive, with eggs and embryos dying in experiments when subjected to the high end of salt concentrations.

Scientists who study road salt's effect on the ecology do not, however, advocate leaving icy roads untreated. They hope to learn more about how to prevent salt's negative impacts without sacrificing public safety.