Ice, ice, baby: Is run-off ruining the waters?
Without them, your car would be all over the road– if you ever even escaped your driveway. But are salt and de-icing chemicals ending up in our waterways and harming fragile ecosystems?
"Salt is very bad for plants," says naturalist Marlene Condon. "It kills them if there's too much." The publisher of a new nature newsletter, The Happy Habitat, Condon says that freshwater animals cannot survive in water with a high saline content.
That's bad news for wildlife in Charlottesville, which, like most other localities, relies primarily on salt for keeping roadways clear.
Stephen Mays in the city's public service department says run-off from city roads enters storm drains that empty directly into waterways including Moore's Creek and the Rivanna River. From there, the tainted water makes its way east, eventually entering the Chesapeake Bay.
How bad is it?
Dave Hirschman, Charlottesville/Albemarle County Water Resources Manager, says that while salt is not good for waterways, he hasn't seen terrible environmental effects locally.
During a heavy rain or a quick melt, he says, there may be enough dilution to counter the ill-effects, because "the toxicity of the salt depends on the concentration."
As for the Chesapeake Bay, there are things far worse than a little– or even a lot of salt.
"Road salt pollution pales in comparison to the other pollutants," says Chesapeake Bay Foundation spokesman Chuck Epes. The Bay is an estuary– a combination of fresh and salt water– so its ecosystem has evolved over time to accommodate fluctuating salt levels, says Epes.
Of much more concern, he says, are "nutrient pollutants" such as phosphorus and nitrogen, which are released in large quantity into waterways from wastewater treatment plants and from fertilizer used on farms and golf courses.
Bob Wichser, director of the Rivanna Water and Sewer Authority, says the fact that Charlottesville's storm drain run-off– and road salt– goes straight into the waterways, rather than through a treatment plant, is preferable.
"From our standpoint," he says, "we're lucky."
When road salt, or sodium chloride (NaCl), enters a wastewater treatment plant, says Wichser, it inhibits the biological waste break-down process and allows higher levels of nitrogen in the effluent.
Wichser cites the water system in Richmond, in which storm drain and sewer runoff commingle, reducing the quality of the effluent flowing into the James. That's bad news for the river, he says, and for the Bay downstream.
As for salt in the soil, Wichser points out that most plant life is inactive during the winter, so there's time for the salt and chemicals to dilute before spring growth starts.
Jim Jennings, a VDOT spokesperson, says it's the storage of salt that can cause real problems.
"If you have a dry winter, you could end up with 300 tons of salt just sitting and dissolving into the soil," he says.
In Charlottesville, Jennings says, measures have been taken to keep the salt dry and prevent it from leaching into groundwater. All salt stores sit on concrete or asphalt pads and are covered to prevent rain from washing the salt away.
Mays says Charlottesville does what it can to control salt use, particularly on bridges, where salt could corrode the multi-million dollar structures. The city generally puts down 250 to 500 pounds of salt per road mile, says Mays.
To keep bridges safe for drivers, the city began spraying some of its salt with a corn-based liquid de-icer called Ice Ban back around 1999.
Because it's biodegradable, says Mays, Ice Ban is less harmful to plant and animal wildlife. "If you pour it on grass," says Mays of Ice Ban, "the grass grows faster."
And it's non-toxic to animals as well.
"If a dog licked it," he says, "it wouldn't kill him."
An added bonus: It de-ices roads even at temperatures below 20 degrees, when salt typically becomes less effective. This winter, when temps have routinely dipped into the teens, Ice Ban has been especially important. And lastly, says Mays, Ice Ban reduces the corrosiveness of salt, reducing the amount of damage to bridges.
The downside? "It's much more expensive," says Mays, explaining that the city doesn't have the budget to use Ice Ban more extensively.
As for sand, Mays says it's useful for providing vehicle traction, but has no de-icing capacity. If too much is used, he warns, it can also clog the storm drains and requires extensive post-melt clean-up.
Hirshman adds that sand, though seemingly the least harmful to the environment of any winter road treatment, comes with its own dangers.
"If too much is used," he says, "it can fill up the rocky crevices in stream beds where aquatic wildlife and insects make their homes."
So is there any way to have safe roads and happy streams? Perhaps if everyone stays home when it snows.
"It's a value system," says Hirschman, who acknowledges the economic necessity of road travel. "Everyone's so anxious to get back in their cars, but is it at the expense of the environment?"
Salt in the drain: big problem or no big deal.
PHOTO BY JEN FARIELLO