WASHINGTON – Maryland highway officials are armed with new snow-melting technology to fight the forces of Mother Nature this winter, but the chemicals they plan to use may cause more of a stir than the weather itself.
Environmentalists worry that some of the chemicals the State Highway Administration plans to use in its “anti-icing” campaign will solve one danger but create others.
“This is a big problem,” said Vivian Newman, conservation chairwoman for the Maryland chapter of the Sierra Club. “There’d be an immediate impact on the roadside vegetation and it will get either into the groundwater or into open water and into the bay.”
Environmental groups are particularly concerned about the state’s plan to spray salt brine, a mix of water and sodium chloride, to treat thousands of miles of roads this winter. The brine was tested last year in Montgomery and Washington counties, but this is the first year it will be used statewide.
“We found that it was effective [on the roads], and that is was also cost effective,” said Sandi Dobson, an SHA spokeswoman.
Dobson said that SHA will be taking precautions when using the brine.
“We’re making sure that the spreaders are not over-spraying,” she said. “And we won’t be using it heavily in areas where we’re concerned about run-off.”
Salt brine, which can be applied eight to 10 hours before a storm hits, is part of a new SHA anti-icing strategy. The liquid solution, which costs about 5 cents per gallon, will be sprayed on major highways to create a barrier on road surfaces that prevents icing.
Officials at the Environmental Protection Agency say salt brine can pose a threat to streams and other freshwater sources.
“Salt is toxic in excess amounts when added to fresh water,” said Jeff Grubbs, director of the EPA’s Office of Science and Technology. “It can cause localized problems to fish and aquatic life.”
The SHA said it will not use salt brine in areas that it considers “environmentally sensitive,” such as the Conowingo Dam on the Susquehanna River. Dobson said road crews instead will use CMAK, an acetate solution, in those areas.
“Unless it’s in very high concentrations, it (CMAK) is not going to do much damage,” Dobson said.
SHA officials say CMAK is the most “environmentally friendly” of any of its chloride chemicals, but at $4 per gallon, its use is limited.
A new anti-icing system installed on a bridge on Interstate 68 in Western Maryland will automatically spray CMAK on the bridge surface to prevent frost, snow or ice from bonding with the pavement. Officials said that if the technology works, it might be installed on other state bridges in the future. Bridges generally freeze faster than other road surfaces and can be more hazardous for drivers.
The state also has magnesium chloride in its road-clearing arsenal, but Dobson said that in most areas, the state will still rely mainly on 250,000 tons of rock salt to combat icy or snowy roads. Dobson said the rock salt poses more of a threat to cars than it does to the environment.
“It’s very corrosive,” she said. “It’s more damaging to cars and chipping paint than it is to growth.”
Newman said rock salt is also unsafe for the environment, but she does not suggest that Maryland give up its efforts to make winter roads safer. Instead, she wants the state to consider the environmental effects of expanding chemical use for treating roads.
“We know that there are a lot of dilemmas here because we want (highway) safety, but we also want environmental protection,” she said.