Ice Melt A Hot Commodity, But Is It Eco-Friendly?

If your sidewalk or driveway looked like most other people's in the past week, then you must recognize this noise.

It's ice being chipped, scraped, and shoveled away. Local streets have been coated with the stuff lately, and rock salt and ice melt are flying off store shelves.

But where do these products go after they melt? And are they safe to put all over the ground?

WBUR's health and science reporter Sacha Pfeiffer reports.

Just how in demand have ice melting products been in recent days? Here's George Shipps, the floor manager at Swartz True Value, a hardware store in Newton that has stacks of ice melt on display inside and outside the shop.

GEORGE SHIPPS: In one day we did more in sales than we'd done the previous week. I mean, it was just unbelievable. And most of that was just in ice melt.

Like most hardware stores, Swartz sells many kinds of ice melt. It comes in pellets, flakes and liquid, and it has names like Super Melt, Clear Path, and Inferno.

No matter the brand, most ice melt products are some form of salt. That's because salt can prevent ice from forming by lowering the freezing point of water. Salt also melts ice by releasing heat as it dissolves. It's such an effective ice melter that just about any kind will work. Again, George Shipps.

SHIPPS: I remember as a kid my grandmother using a box of Morton's table salt and just spreading that around.

But all that salt worries Bill Fash of Newtonville. He recently came back from vacation and found more than an inch of ice on his sidewalk and driveway. He says he chipped most of it away because he's concerned about the environmental impact of salt.

BILL FASH: Well, you know, you see these signs on the highway that say 'limited salt area' and you realize probably everything should be a limited salt area, and you see all this stuff going into the gutters, and it can't be healthy.

He's right — too much salt can kill vegetation and animals by dehydrating them. It can also leach into soil and contaminate drinking water supplies.

Bob Zimmerman, executive director of the Charles River Watershed Association, says salt can also damage metal and asphalt, including cars, roads and other manmade structures.

BOB ZIMMERMAN: Besides the environmental impacts, there are impacts on the longevity of bridges, on the hardness of concrete.

Even ice melt products that are tinted green and claim to be eco-friendly are often made of salt, sometimes sea salt. But ice is a reality of winter, and it has to be removed for public safety.

So what should an environmentally conscious person do? Zimmerman says he uses sand, which does more than just provide traction.

ZIMMERMAN: It actually breaks up the ice faster because it stays there longer. And because it darkens the surface of the ice, it attracts heat and actually melts the ice. It's great.

If you do use salt-based ice melts, Bruce Berman of the Boston environmental group Save the Harbor/Save the Bay says you should use as little as possible if you live near bodies of water that don't get regularly flushed out.

BERMAN: If your house drains directly to a small pond, then you'd really want to be careful because the water's going to sit in a small pond forever. If it drains into a larger river system or into the harbor, those systems are more robust and can take a bit more abuse.

Berman says salt that ends up in the ocean gets diluted so quickly that it usually does little harm. He says it also helps that winter only lasts for a season so salt run-off doesn't happen year-round. Still, he advises that salt be used in moderation.

And you could always dream, like Bill Fash of Newtonville does, that one day ice won't be a problem at all during New England winters.

FASH: We're hoping that when the day comes when we have to redo our driveway we'll put some sort of solar-powered electrical heater in the driveway so that as long as there's sunlight hopefully there won't be ice on the driveway.

But until then, get out the sand and ice picks and keep your salt use to a minimum.