The history of the sugar beet has far more twists and turns than you might expect, from Napoleonic orders to anti-slavery movements. One of the newer uses for the sugar beet lies in using a mixture of sugar beet extract and salt to create a deicing material for city streets. Several cities have gotten on board recently, including Washington, DC and Toronto. But is this beet solution really an environmental solution as well?
The idea of using beets purely for their sugar content dates back to the mid-1700s, when scientists started to analyze the properties of boiled beets—specifically, their relatively high sugar content. During Napoleon’s reign of France, sugar beet production ramped up, with Napoleon very interested in the possibility of domestically grown sugar. Sugar produced from sugarcane was limited to tropical climates, especially in the Caribbean and Napoleon was losing control of France’s Caribbean colonies.
Sugar beets, which are white in color, are best suited to a temperate environment. Soon researchers across Europe and North America started cross-breeding beets to have higher and higher sugar contents, eventually reaching around 20 percent today. The sugar beet industry also received a boost from abolitionists in the United States, who objected to the slave colonies in the Caribbean and sought a more ethical alternative. Today, sugar beets provide more than half of the sugar produced in the United States. But that also means that there’s a great deal of non-sugar detritus that comes from beets, and there’s a continual effort to figure out what to do with all the pulp and other stuff left over from the sugar refining process.
A pile of just-harvested sugar beets. Photo by goodbishop, Shutterstock.
One of those uses, over the last decade or so, has been as a deicer. Those of us who grew up in snowy climates are probably familiar with the salting trucks that scatter rock salt over snowy roads during the winter. Rock salt is an extremely effective and cheap deicer; it works by, confusingly, lowering the freezing point of the layer of water on top of ice. That action, though, raises the temperature of the water, which in turn raises the temperature of the surrounding water and soon the ice starts to melt. The more salt you use, the faster it will all melt.
But salt is also very destructive to the environment. A study found that freshwater in colder parts of the country had a much higher saline content than in years past, attributing much of this to road salt. Higher salinity is very bad for wildlife, especially aquatic wildlife, and tends to persist for a very long time. Salt is also super corrosive on infrastructure like roads and bridges, not to mention on cars themselves.
Beet deicers, as a recent story in Bloomberg shows, are gaining traction in cold cities, especially in Canada. They’re made from a mixture of sugar beet molasses—a waste product—and some, but much less, salt. The sugar in the beet molasses seems to be even more effective than salt alone: it, too, lowers the freezing point of water, causing it to melt, but it’s also nicely sticky. Rock salt may persist in the environment for a long time, but it’s not great at staying on roads, where it washes away easily and has to be reapplied. Beet deicers, though, are sticky and stay on the roads to handle multiple snowstorms. And they’re fully biodegradable.
This all sounds fantastic, but over the past few years, there’s been some environmental concern about this sugar beet brine as well. Some research has indicated that beet juice deicer can be harmful to insects including the mayfly, which are important prey species in their aquatic larval stage. Beet deicer has also been linked to a high biochemical oxygen demand: When microorganisms break down the beet juice sugars, they dramatically reduce the amount of oxygen in a waterway, which can essentially suffocate aquatic animals like fish and amphibians. Michigan’s Department of Environmental Quality notes that in topographically flatter places like Michigan, the slow movement of waterways makes them especially susceptible to this kind of event.
Seeing no fault-free way to rid the streets of ice, even the cities that are using beet juice as a deicer tend to also use salt, reports Bloomberg.