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Issue 14
November 30, 2001
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Get a Grip on Road Salts This Winter
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Canadians depend on road salts to keep icy roads and sidewalks safe. But what happens when the salt comes into contact with the environment?
Environment Canada scientists recently completed a five-year scientific assessment report on the impacts of road salts. This comprehensive study showed road salts in sufficient concentrations can have serious effects on the environment resulting from high releases around storage and snow disposal sites and run-off from treated roadways The assessment focused on environmental impacts since there is no evidence of impacts on human health.
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No Ban on Road Salts
Road salts are the de-icer of choice and will continue to be used by road authorities to ensure road safety.
The Government of Canada is not proposing to ban the use of road salts and is looking at new and innovative solutions to address the harmful effects of road salts on the environment without compromising road and driver safety.
A 60-day public consultation period begins on December 1st, 2001 where Canadians can comment on whether road salts should be listed under the Canadian Environmental Protection Act, 1999 (CEPA, 1999).
Over the next two years, management measures will be selected and developed with input from all levels of government as well as transportation and road maintenance authorities, industry and community environmental groups. This co-operative effort will strengthen existing salt management guidelines developed by the Transportation Association of Canada.
Road Salt Use and the Environment
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Diagram of sources and dispersal of road salts in the environment. Click to enlarge.
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Approximately five million tonnes of road salts are used in Canada on an annual basis. Application rates are highest in and around urban centers. Once spread onto roadways, road salts eventually find their way into waterways through road-side snow melt or salt splash. They can also travel distances when absorbed by soil or underground water systems.
Road salts are persistent in the environment—meaning they don't go away. Salt splash associated with heavy use in treating roadways can damage road-side vegetation. In surface water, road salts harm freshwater plants, fish and other organisms that cannot survive or thrive in salty waters. Although not harmful to human health, road salts can affect the taste of well water.
Management Options
Management options will focus on the way road salts are currently handled, stored and used. By rethinking current management practices, the effects of road salts on the environment can be reduced without affecting road safety. A broad range of options include:
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- better storage and handling techniques around salt storage sites
- improved salt application technologies and practices
- alternative products
- meteorological forecasting tools that reduce salt use
Better storage and handling techniques around salt storage sites will improve by loading spreaders inside storage facilities. In some locations drainage is being collected and used in brine production.
Better planning and design of snow disposal areas will improve handling of contaminated runoff. Increased use of alternatives like liquids in pre-wetting and anti-icing in warmer parts of the country will lead to the reduction of road salt stockpiles.
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Typical tower at Road Weather Information Systems station
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Technology will continue to play an important role in winter maintenance. Advancements will provide greater accuracy in where and when salt is spread using Road Weather Information Systems (RWIS) and Global Positioning Systems (GPS) linked spreaders.
The Road Ahead
Considerable effort is being made by road authorities at all levels to introduce improved roadsalt management approaches for road salts. This co-operative effort will benefit provinces and territories just beginning to consider new initiatives and new technologies like:
- electronic spreader controllers: sophisticated spreaders with electronic controllers are now able to place precise amounts of salt more accurately on the road surface.
- anti-icing: early application of chemicals or brine to prevent formation of the road/ice bond. This early application of salt means that the snow plows can do their job sooner and more effectively.
- pre-wetting: addition of a liquid (preferably a salt brine) to salts or abrasives prior to the application to the roadway. When a liquid is applied to a particle of salt, the particle begins to soften and dissolve so that when the particle hits the roadway, it is less likely to bounce off the road or be swept away by traffic.
- Road Weather Information Systems: use weather and road data from automated weather reporting stations installed along the roadway which also have special sensors embedded in the road, to assist weather forecasters in predicting icing conditions before they occur.
In the future, Canadians can expect better management of road salts to improve road salts application, storage, snow disposal techniques as well as the use of alternatives products. Actions like these are already underway in provinces, territories and municipalities to enhance management techniques through cooperation and partnerships and above all, to maintain road safety.
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