Salt
Road Salts are composed of ferrocyanide, potassium
chloride, sodium chloride, magnesium chloride, and calcium chloride salts. The
main component of road salt is the same table salt used for food, and while the
only probable human affect of road salt is the adverse taste of contaminated
roadside well waters, its effect on vegetation, wildlife and water quality can
be devastating.
These salts enter the environment through use on roadways, streets and sidewalks and through the disposal of waste snow. The runoff of melted snow can result in high concentrations of chlorides in surface water. After a week's exposure to concentrations of 1,000 mg/l,[1] Rainbow trout perish. Approximately 10 % of aquatic species are harmed by prolonged exposure to chloride concentrations greater than 220 mg/l. Additionally, high concentrations of chloride can increase the presence of metals in the waters and prevent the distribution of oxygen and important nutrients. Salts have been shown to damage vegetation as far as 162 feet from roadways that were treated, thus plant species susceptible to damage by salt are disappearing along roadways. As plants die, wildlife can be affected and road salt can have both behavioral and toxic impacts on animals and birds.