Beet it: Road ice needs to be defeated
In cold states like Maryland, this root vegetable is a great eco de-icer.
Tue, Mar 24 2009 at 1:34 PM
You’ve sliced them into your salads. You’ve boiled them down to borsch. They may even sweeten your soda. But you’ve never seen the mighty beet quite like this: cast onto city streets as a deicer during winter. That’s right; among the sugar beet’s many qualities is an ability to fend off freezing in sub-zero conditions.
More specifically, it is the sugar beet’s by-product — a de-sugared liquid typically fed to animals or flushed down the drain—that can withstand temperatures down to -30 °F. In the same way the gin in your icebox has a low freezing point, so does this sugar-free beet juice. Legend has it that a farmer discovered the vegetable’s unique quality when a pond where he dumped his beet remains never froze.
Fable or not, today, combinations of beet juice and rock salt are being sprayed on streets and highways by the transportation departments in DC, Missouri, and Ohio and in cities scattered throughout the Midwest and Northeast. The mixture is reported to have a lower freezing point than salt alone and stays on the road longer, reducing the number of applications. The Ohio DOT says it’s currently testing a beet-salt concoction called GeoMelt in 9 of its 88 counties.
“It may take us a couple of seasons to see the effectiveness. We want to make sure the money we spend proves the result,” before increasing their use of it says information officer Joel Hunt. So far they’ve applied 35,000 gallons this year.
While it’s fun to envision beet molasses staining streets and pedestrians red (and, actually, the stuff is brown and leaves no trace), there’s a serious reason behind its rise in popularity. In 2005, the US purchased more than 20 million tons of rock salt, an all-time-high, to pour on our roads and keep them ice free.
Usable roadways are essential, but there’s an environmental cost to dousing them with so much sodium chloride. A 2005 study published in the Proceedings of the National Academy of Sciences (PNAS) found that if we continue our current road salting practices in the northeastern US, chloride concentrations in many rural streams will exceed 250 mg/liter—the maximum limit for national drinking water secondary standards—in the next century, making them undrinkable and toxic to freshwater life.
A century may sound like a long time before our rural streams are too salty to consume, but some waterways are already in trouble. Since 2001 EPA scientist Paul Mayer has been studying ground and surface water near Baltimore, Maryland. He’s found that already it consistently measures 250mg/liter year round and sometimes twice that high.
“We have evidence that indicates road salt contributes to that chronically elevated chloride level,” Mayer says. “You would expect to see that level in brackish water.”
The trend is not easily reversible. Ground water tends to accumulate salt over long periods and then feed it into surface water. According to Mayer, “If you stopped adding road salt today, it might take decades [to leave the system].”
So are beets the answer? Beet juice is 100 percent biodegradable: “I could drink it. It’s completely safe,” says Mike Bellovis, owner of the beet juice company GeoMelt. The stuff also cuts salt application by 25 percent, according to GeoMelt. And that’s not nothing when you consider the state of Ohio alone uses 650,000 tons of salt each year.
But even beet juice isn’t completely innocuous. Adding it to water can have an impact says Sujay Kaushal, assistant professor of environmental science at University of Maryland’s Chesapeake Biological Laboratory, and lead author of the PNAS study.
“Organic matter—anything from leaves to amino acids—anything carbon based that breaks down, needs to consume oxygen,” explains Kaushal.
Oxygen-depleted water can also come at an environmental cost, killing animal and plant life. In one of the most extreme cases of oxygen depletion, known as hypoxia, more than 22,000 square km in the Gulf of Mexico lost much of its commercial fishing industry.
While Kaushal says he has not studied the effects of beet juice on fresh water specifically, he sees a larger problem with adding anything to our water systems. The solution, he says, lies in how and where we build our roads.
The increasing mileage of roads and other impermeable paved surfaces causes more debris to be flushed into waterways. The web of streams, rivers, lakes, and wetlands that converge into a single waterway is called a region’s watershed, or drainage basin; according to a 2002 Pew Oceans Commission study, a watershed begins to change in shape, temperature and pollution level once 10 percent of its land area is paved.
“Don’t feel bad about what we do with deicer,” Kaushal says, “because it keeps accident rates down. The driving factor is land use.”
So, even if the beet can’t fix the root of the problem, it could unearth questions as fundamental as how to keep our drinking water clean.
Story by Victoria Schlesinger. This article originally appeared in "Plenty" in February 2008.
Copyright Environ Press 2008