With polar temperatures persisting across the Eastern United States, many homeowners are turning to technology instead of shovel power to remove ice and snow from sidewalks and driveways.
Consumers have more options than ever for chemicals that lower the melting point of ice and also promise not to harm pets or the environment. But some experts say that many of these chemicals do not break down quickly, and that guilt-free claims aren't always accurate.
"We occasionally test some of the products for homeowners and usually they are not as good as they claim," said Xianming Shi, research professor at the Western Transportation Institute at Montana State University. "They still have some risks. There are a lot of claims out there, and some are misleading."
In recent years, ice-melting product manufacturers have been touting different "organic" additives such as beet juice, cheese or corn byproducts that are mixed with the various kinds of salts, or chlorides, in the solution. Shi says the additives may help the material stick to surfaces, but the real work is done by the salts.
"Because the chlorides are so cheap, they will stay (in the marketplace) for a long time," Shi said. "The big picture is pretty scary."
Shi said that there are increasing reports of salt in drinking water supplies that occasionally exceed EPA limits. But he said there's not enough data or testing about whether sidewalk de-icing is to blame. As for road surfaces, which get tons more de-icing products dumped on them, most cities and counties are keeping it old school.
"Without a doubt, the number one chemical that we use on the roads is good old fashioned rock salt, sodium chloride," said Wilfrid A. Nixon, professor of civil and environmental engineering at the University of Iowa. "What we are trying to do is not melt the snow and ice, but stop it from melting to the road surface. The way you get it off the road is with a plow."
New additives are too expensive for most municipalities; so are heated roadways, which would eliminate the need for applying chemicals in the first place. Sand or dirt is sometimes spread on roads to provide temporary traction, although most of it is blown away by vehicle traffic, according to Nixon.
Although the cost of salt is still pretty cheap, there are hidden costs to cars, trucks and road surfaces. It also tends to remain on your lawn way beyond the spring melt, according to the experts.
"People should avoid putting more and more chemicals because it will go into your yard and it will be there next spring," Nixon said. "(Flowers) might not bloom with too many chlorides around."
She says there’s no good solution for now, unless someone devices a solar powered heated walkway, or perhaps a new kind of nanotechnology surface that could interact with ice to form a barrier and make it easier to remove.
"Every decade we switch to something else," Shi said. "Now we are seeing deterioration of asphalt pavements, or composite breaks in aircraft. Usually you solve one problem and have two more."