Linda Poon is a staff writer at CityLab covering science and urban technology, including smart cities and climate change. She previously covered global health and development for NPR’s Goats and Soda blog.
An unusually severe winter is forcing the city to reconsider its decades-long policy of shunning salt on icy roads.
Portland, Oregon, has a salt problem.
Historically, both the city and the state transportation departments have avoided using salt as the first line of defense against icy roads, citing a mix of environmental and financial concerns. But with unusually heavy snowfall in the Pacific Northwest this winter, frustrated residents are pressuring both agencies to break from decades of tradition for the sake of safety and economics.
And so, the agencies abided, cautiously.
The Oregon Department of Transportation (ODOT) changed its policy in mid-December, declaring that salt would finally be used statewide on a “limited basis.” (Previously, it had used road salt near state lines with California, Nevada, and Idaho to smooth the transition from state to state.) That move came after an inch of snow paralyzed Portland, and at the final leg of a five-year test on the strategic use of salt. ODOT also used salt in Portland, on a nearby highway, for the first time earlier this month.
The Portland Bureau of Transportation (PBOT) also tested salt treatment for the first time this winter, applying salt given by Seattle in especially “troublesome” areas after a historic storm dumped up to a foot of snow in January, leading both Governor Kate Brown and Portland Mayor Ted Wheeler to declare a state of emergency. But the city’s response ultimately fell short. With snow lingering for days, it was clear that the usual method of pounding the snow and spraying sand and magnesium chloride wasn’t enough to break down the ice.
PBOT has no immediate plans to adopt any new policy regarding salt use, but city commissioner Dan Saltzman, who oversees the transportation bureau, says they will start looking at the impacts of different options. “I'm going to set up a task force to look at the pros and cons of using [salt] on a more regular and widespread basis,” he says, adding that he hopes for a “robust process” to implementing salt use, which could take up to three months. For the time being, the city is looking for extra salt and brine (and a place to store them) to have on hand and to be used where necessary.
The agencies have to maintain a delicate balance between safety and environmental protection, and they’re being cautious for a good reason: that salt wreaks havoc on the world around it. Anyone who’s trudged through a city in the midwest or along the East Coast after the slightest snow storm can probably recognize the dreaded stains of a heavily salted pavement. The trail of white residue clings to shoes and corrodes the underbelly of passing vehicles and the pavement itself. But it’s where the rest of the salt ends up that has environmentalists and health advocates pushing for alternatives.
“It doesn't just disappear,” says Lori Grant, water program director for Oregon Environmental Council. “When salt is applied on the roadways, it eventually dissolves, and it either seeps into groundwater or into storm drains, which usually flows into the nearest body of water.” Of larger concern is the chloride component of salt (sodium chloride) which is highly soluble and travels more efficiently in water, contaminating waterways and threatening both plants and animal life. Not to mention, researchers have also found that road salts contaminate local drinking supplies.
A 2014 study by the United States Geological Survey looked at chloride levels of 19 urban streams in cities across the country—including in Wisconsin, Colorado, Pennsylvania, and the District of Columbia—between 1980 and 2010. They found that, due largely to the use of road salt in those cities, 84 percent of those streams saw substantial increases in chloride concentrations. A third had levels that exceeded the recommended level for aquatic life set by the Environmental Protection Agency.
One stream that saw practically no change in those years is the Willamette River, which runs through Portland. That’s because the city hasn’t used salt as a de-icing agent for decades. The river, according to Grant, is a priority among local environmentalists. “It has plenty of its own issues that are just compounded by adding one more toxic chemical, in effect, to what salt is when it enters the waterway,” she says, adding that Oregon also has a number of snowy roads that drain water into creeks, and eventually the ocean. “Those are some of the most pristine rivers we have.”
Grant wants Oregonians to know that salt isn’t the only—or even the most effective—solution out there. Indeed, in an effort to cut back on salt, whether for environmental or financial reasons, other cities have tested all kinds of environmentally friendly alternatives. Many are byproducts from the industrial food processes, and while they don’t all eliminate the need for salt, they at least mitigate it. The Farmer’s Almanac, for example, touts alfalfa meal as an all-natural solution. The nitrogen in it melts the ice while the grainy texture provides traction.
Milwaukee raised eyebrows years ago when it repurposed cheese brine and dairy waste to keep roads from freezing. It not only saved money for the city, but dairy manufacturers benefitted from free waste processing. According to Wired, leftover juices from mozzarella and provolone works best because of their high salt content.
Perhaps the most popular alternatives involve beet and pickle juice. Pickle juice, which Bergen County, New Jersey, turned to when its plowing budget stated to dry up, works similarly to salt water. And in the last few years, cities like Washington, D.C., Boston, and even Toronto, have turned to a beet-brine solution—sugar beet molasses mixed with salt—to melt ice at cooler temperatures. Beet juice manufacturers say the sugar lowers the freezing point; when mixed with salt, the solution can be effective in temperatures as low as -20 or -30 degrees Fahrenheit. (Salt, by itself, can become ineffective when the temperature reaches 10 to 15 degrees Fahrenheit. Plus the thick goo helps prevent runoff.
In Portland, Saltzman acknowledges the urgency. Oregon is in for more severe winter storms, and with an arsenal of only 55 snowplows (plus another 11 borrowed from Seattle) that can handle some three inches of snow, the city has been unprepared. Small businesses were among those hardest hit in January’s storm, with owners forced to close their shops for days. According to local newspaper Oregon Live, the season has caused some to lose at least a week’s worth of sales. Students have missed multiple school days, and icy roads puts residents’ safety at risk.
“The last snow and ice event really produced a lot of snow, and unlike normal, it didn't melt away the next day,” he says. “We had very low temperatures, so it stuck around for almost a week, and people were pretty much at their boiling point.”