Smarter Living: Stuff
Safer De-Icers for You and Your Pets
Photo: Maureen Shaughnessy
Ice is an obvious hazard to life and limb for us, but our more sure-footed canine companions are likely to be bothered neither by the cold nor the ice. For them, as well as for the health of our waterways and wild animals (see "Salty Cities"), salt is not the best substance to have sticking to their paws and not every dog can stand to wear boots.
Best choice: Gravel
To make an icy walkway passable, you just need traction. Gravel is cheap, non-irritating and easy to spread, with sand a good second best, though it must be cleaned up to avoid it running off in waterways and causing sedimentation. Otherwise, their environmental impacts are minimal and they pose no problems for canine paws.
If an ice storm is coming, cover key areas with heavy plastic beforehand. Then take the sheeting up as quickly as possible after the storm to avoid it freezing into place. Large boards can serve the same function.
Trouble spots may be require chemical de-icer, so when looking for one, consider these points:
Most chemical de-icers are irritants and should be washed off immediately from paws or hands with soap and water.
Chemical de-icers, including magnesium chloride, can cause leaching of heavy metals from the soil, bringing them to the surface and into the groundwater.
Save any de-icer for the most dangerous spots, where a small amount will serve to release ice from pavement; apply before ice has built up.
Carbonyl diamide: Do not use
Carbonyl diamide, or urea, releases nitrate when it enters the water supply, nourishing algae just as nitrogen fertilizers do, which can result in algae blooms that choke out other vegetation as well as fish and shellfish. Toxic ammonia is also released when urea reacts with water. Urea is extremely corrosive to metal and isn't always effective below 20 degrees F.
Chloride Salts: Avoid if possible, apply only on trouble spots
Chloride salts corrode concrete and metal, damage vegetation, and irritate the skin of pets, which can even poison themselves while trying to lick their feet clean. Magnesium and calcium in particular can mark carpets and floors; sodium and potassium are less bad.
Chloride salts, including table salt (sodium chloride), magnesium, calcium, and potassium chlorides function at different minimum temperatures:
magnesium chloride -13F
calcium chloride 5F
sodium chloride 18F
potassium chloride 25F
Calcium magnesium acetate (CMA): Apply on trouble spots
CMA works slowly and only at mild temperatures; still, it's a more effective de-icer than urea and lasts longer than most chloride salts. Better, though, is that it doesn't corrode metal or concrete and doesn't harm vegetation. However, it can temporarily deplete oxygen in small lakes, but not on the scale of urea. Because CMA biodegrades and isn't especially mobile in soil, it isn't a major threat to most groundwater.
Potassium acetate (KA): Apply on trouble spots
Although not as well studied as CMA, it appears to be similarly benign and to work at colder temperatures than either CMA or salt.
last revised 1/23/2012