Salting the roads or the walkways for snow removal is illegal in California. If you’re driving in the mountains in California, say to Tahoe for a ski vacation, you carry chains. There are turnouts on all the highways, like rest areas, for you to stop and hook the chains onto all four wheels of your car. They’ll plow, but they won’t salt.
Removing snow and ice in New England is a little different. Making driveways and walkways passable and safe requires some kick-ass chemicals. At least, we believe so.
Winter ice bonds with pavement and other surfaces. Ice is like paint – it’s not just a layer sitting on top but is a layer actually knitted to the surface. What chemical de-icers do is either break that bond or prevent the bond from happening. A de-icer, of course, is a chemical agent that is spread on snow or ice.
Let’s look at the usual chemical suspects.
Chemicals for snow removal
Snow removal chemicals are either acetates or chlorides. Acetate chemicals are biodegradable and are believed to have low impact on the ecosystem after being washed off the parking lot and into streams, soil, gardens. Chlorides are salt-based and are more “corrosive,” as chemists like to say. This means “toxic” to organic life and means “eats away” at inorganic life, such as cement, wood, and the underside of the car.
Chlorides for Snow Removal
Rock Salt and Sodium Chloride
> Rock salt and sodium chloride is the most common chemical used in snow removal compounds, but only effective above 20 F. Rock salt can be corrosive to rebar and steel but has relatively low impact on concrete. It’s not health food for the ecosystem, significant concentrations can mal-affect flora, fauna and ground water. Problems, according to the National Academy of Sciences (NAS), include salt toxicity to plants and fish, groundwater contamination, and human health interactions, particularly salt intake and hypertension.
Urea and Potassium Chloride
> Potassium chloride is a fertilizer. It’s also effective for melting ice. The chemical is said to be safe for plants at low doses, though in high concentrations it may prove deadly to the same plants. Urea does not contain chloride, so it does not carry the corrosive risk to steel and rebar as other chloride-based snow removal chemicals.
> Calcium chloride is a liquid. It absorbs moisture from the air, thus essentially “dehydrating” the ice so it dissolves. As a snow removal chemical, it is effective in very cold temperatures – colder than Boston, closer to Fargo or Quebec City type temperatures. Calcium chloride does not require heat to work and is the less-corrosive of the chlorides.
> Magnesium chloride is considered less corrosive and kinder, gentler to plants and animals than many other snow removal chemicals. The problem with magnesium chloride is that it’s not as concentrated as other chemicals, so more is used; more chemicals is good for the manufacturer, not always good for the ecosystem.
Acetates for Snow Removal
Sodium Acetate and Calcium Magnesium Acetate are non-liquid, non-corrosive and by most accounts biodegradable chemical substances for snow dissipation. Downside: these chemicals change snow into slush, making it less than ideal for walkways and other high traffic areas. Makes a mess of nice shoes.
> Acetate potassium
Used in liquid form and good in cold temperatures, like Montreal. The chemical-substance sticks, so over the winter less is needed – the stuff already on the ground acts as an anti-icer, or “snow melter on contact.” Cleaning it up in spring can be a problem.
New England snow
Anyone who’s ever skied Tahoe then skied in New England knows the difference: the snow here in New England is more ice-crystals than the slushier. more forgiving type of snow in the Sierras. (As a native New Hampshirian, I ski like a pro out west, when in the east, at Mount Sunapee say, I’m just shy of completely out of control.)
For more on the potassium chemicals, go to this excellent site on fertilizer chemicals. Site is http://www.pesticideinfo.org. With New England this year being the snow removal capital of the universe (it seems), then with planting season coming along, we should get to know our chemicals.
I mean, can’t we all just get along…?