Winter's byproduct: Road salt
Road runoff and spray affecting wetlands
By DANIEL E. GOREN, Standard-Times staff writer
State highway workers scattered more salt on Massachusetts roads this winter than almost any other winter, with the total cost of removing snow from the interstates soaring to a record $107 million so far, officials from the Department of Transportation said.
Drivers place a premium on having clear roads, but highway officials are left to navigate a delicate calculus between driver safety and possible environmental impacts on drinking water, roadside vegetation, wetlands and animals.
With relatively little research done on road salt's impacts, scientists are starting to accumulate data that show the harmful effect of dumping vast quantities of sodium chloride on highways each winter.
"It is damaging to the environment if heavily used," said Tom Langen, an assistant professor at Clarkson University in New York who studies ways to reduce road salt usage. "We have to be concerned with how much we use and where and when we use it. Anything we can do to reduce the usage of salt is a good thing, because so far there are no great alternatives."
This winter, 703,460 tons of salt costing $29.1 million has been unloaded on Massachusetts highways, making the Bay State one of the most prolific salt users in the country. Of that, 65,229 tons costing $2.8 million landed on SouthCoast roads, officials said.
Another significant snowstorm was forecast overnight into this morning.
"As a matter of public safety, you have to go through with snow and ice removal using salt," said John Carlisle, spokesman for the Department of Transportation. "People expect the roads to be free and clear, but you have to do it in such a way to show you are sensitive to environmental impacts."
The use of salt to melt and clear snow dramatically increased after World War II as the highway system expanded. In the 1950s, states started guaranteeing snow-free and ice-free pavement after storms, prompting the use of salt by highway departments to skyrocket.
Today, despite Massachusetts' efforts to more carefully use salt in sensitive areas, contaminated runoff can seep into people's drinking water wells, Mr. Carlisle said. In those cases, the state is dedicated to "mitigating" any damage, he said.
The road runoff from melting snow, which sometimes contains heavy metals and other toxic chemicals, also can find its way into wetlands, vernal pools and freshwater streams, scientists say. It can kill native plants, opening a window for non-native species to take over, and can alter the reproductive patterns of certain types of amphibians and fish.
The spray from car tires also can carry a salty mist 200 to 500 feet from the road, browning the pine needles of sensitive trees, such as the white pine. The spray also can kill some wetland vegetation and potentially shorten the fall foliage season, scientists say.
When too much snow falls, as it did this winter, state officials and municipalities are forced to use dump trucks to haul the salt-laden snow from the streets.
Prevented from legally dumping it in the harbor, New Bedford put its snow in the Whale's Tooth parking lot on the waterfront this year. But as the mounds slowly melt, they also turn black and can accumulate worse pollutants than just salt, such as leaking car fluids left on the blacktop, scientist say. When the piles thaw, the polluted water could wind up draining into the harbor anyway.
"We are concerned about all pollutants coming into the watershed through the fresh water systems that then lead to the bay," said Tony Williams, water monitoring coordinator for the Coalition for Buzzards Bay. "Salt is a concern, just as any other pollutants are a concern."
Nancy Karraker, a Ph.D. candidate at the SUNY's College of Environmental Science and Forestry, has researched the impact of road salt on spotted salamanders, an amphibian common in the Northeast. When salt infiltrates the vernal pools where they breed, the salamanders do not reproduce as readily, she said. But the impact could be felt much more widely than just on amphibians.
"The only way I can really make this make sense to people is to take it out of the realm of amphibians and make it about the larger picture, which is the wetlands," Ms. Karraker said. "People want to spend their summers around these wetlands. They want to swim, they want to fish. Pretty soon, as things die off or get pushed out, they will not be the beautiful places they once were. We are drawn to these places, and if we are not careful, pretty soon they will disappear."
This story appeared on Page A1 of The Standard-Times on March 24, 2005.