To salt or not to salt
Sodium chloride is the most common ingredient used for de-icing roads and sidewalks. Homeowners typically apply it in the form of rock salt. Excessive salt in snow that melts off driveways and walks can leach into the soil, harming or killing turf grass, trees and shrubs. On a larger scale, salt used to de-ice highways can pollute lakes and streams and is also corrosive to road surfaces. Alternative products exist, but each has its own set of pros and cons. A new product that holds promise for reducing environmental impacts is made from a byproduct of the corn wet-milling process. Some highway departments are experimenting with corn-based de-icers, which are also less corrosive to concrete and asphalt.
Alternatives to sodium chloride include:
- Calcium chloride—A widely touted alternative to rock salt. Effective down to temperatures of -31 degrees C compared to -10 degrees C for sodium chloride. About three times more expensive than rock salt, but covers more area. Less harmful to plants than sodium chloride, but still contains salts. Corrosive to metal and concrete.
- Urea—Often touted as an environmentally friendly product, but high in nitrogen, which can damage plants and harm water quality. Significantly more expensive than rock salt. Less corrosive to hard surfaces. Effective to about -4 degrees C.
- Calcium magnesium acetate—Contains dolomitic limestone and acetic acid. Very expensive but much kinder to concrete and plants. Effective to about -3 degrees C.
- Sand or cat litter—Doesn’t melt snow or ice, but can improve traction. Messy cleanup.
For a comprehensive look at these and other de-icing products, go to http://water.greenventure.ca/road-salts-deicers. Regardless of the product you choose, the best way to reduce negative impact is to use only the amount needed. You can easily get carried away with hand-sprinkling. Follow package instructions and measure carefully. Also, be sure to wipe your pet’s paws after walks. Salts and chemical de-icers they lick from their paws can cause serious harm.