April 11, 2014 Salting Our Highways during Severe Winter Weather When I think of salt, my mind goes straight to the salt shaker on my dinner table which I use on a daily basis. Although I know this as iodized table salt, natural salt is actually sodium chloride and is used in a variety of applications. One of the largest applications of salt usage around the world is its use as a road deicer during the winter months to melt ice and improve driving conditions on our highways and roads. In addition, I know that salt combined with water produces saltwater and moderate levels are virtually harmless to most living organisms in our environment. The effects of high salt concentrations and the chloride found in sodium and calcium has raised concern regarding potential pollution of our streams, rivers, lakes, soil, and even our water supplies due to the runoff from roads and highways. In addition, the use of salt to melt ice on roads has become standard practice for state and local governments over the past two decades as the most cost effective way to keep our roads and highways ice free during severe winter weather. According to the report by Findlay and Kelly, salt usage for deicing roads was at 23 million tons in 2005 compared to 10 million tons in 1985 (59, Fig. 1), which is a 57% increase in usage over the last twenty years. In another report by Kim and Koretsky, salt usage for deicing roads was at 164,000 tons in 1940 compared to 15 million tons at the turn of the 21st century (343), which is a 99% increase over the last 60 years. Due to this substantial increase in salt usage, environmentalists began to wonder if the increased use of salt as a deicing agent on our roads and highways threatened our environment in any way due to runoff along the highways. In addition, the use of salt at our homes, businesses, in cities, and in parking lots also contribute to potential pollution due to runoff. Also, at the same time, state and local governments which consume the largest amounts of salt, were also concerned about the effects on our environment. According to the report by Harless, Environment Canada in 2001 classified the chemicals used in road deicers as “toxic and posing a threat to human health and the aquatic environment (1637).”
Although the statement made by the environmental group appears to label salt in the same category as gasoline, I believe it was referring to the chloride chemical contained in the salt mineral. Also around the same time this statement was released, salt usage had risen to its highest consumption level in two decades. In addition, state and local governments had compiled data listing the benefits of using road salt for our economy, infrastructure, and the reduction of accidents due to icy roads. According to the Salt Institute, the use of road salt reduces accidents by 88%, accident costs by 85%, and injuries due to accidents by 85%. Also, the cost of spreading the salt pays for itself in only 25 minutes after application which makes it the most cost effective measure for snow and ice removal (20).
In addition, The Salt Institute of North America is based in Alexandria, VA and has a website with a wealth of knowledge about the benefits of using salt in food, water, on roads, and the benefits for our health. Also, the Salt Institute published the first Snowfighter’s Handbook in 1967 which was dedicated to providing state and local public service workers with the knowledge to combat severe winter weather on our roads by using salt. Calling it Sustainable Snow fighting, the manual states following the guidelines will produce the most cost effective way to melt ice and snow on our roads with the least impact on our environment (3).
In addition, the manual also recommends using a fairly new technique called anti-icing on roadways instead of rock salt for deicing to save time and money on materials when proper winter storm conditions permit.