March 17, 2010

Helping winter roads, hurting the environment


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Staff photo by Jim Evans SALTY SNOW: A man-made mountain of snow from Waterville's streets is piled higher by public works employee David Vigue Thursday morning. The snow dump, at Head of Falls next to the Kennebec River, is piled to make room for more snow expected soon.

Blethen Maine News Service

Road salt kills trees and shrubs, and it contaminates drinking-water supplies.

It also could taint Maine rivers and streams with runoff, but biologists and scientists won't know for years.

On average, Maine crews spread more than 100,000 tons of sodium chloride each winter, and they've gone above that this winter, with 120,000 tons.

Robert Van-Riper, a fisheries biologist at the Maine Department of Inland Fisheries and Wildlife, said people often don't take into account the environmental consequences of using salt to combat icy roads.

''The state Department of Transportation is going to a salt-priority program, not the good old days when they put down sand,'' Van-Riper said last week.

''Now they're making a slurry of salt with water and are spraying it on the roads. Salt causes problems with every aquatic system. The issues with this in essence is we don't ever consider the wildlife or fisheries.''

The state once used 80,000 tons of salt a year, combined with more 530,000 of cubic yards of sand.

Now, according to DOT spokesman Mark Latti, crews are spreading 20,000 tons more salt each year, and they've reduced sand to 10,000 cubic yards.

''We're not putting as much sand into the environment, which also leaches into the river and causes all kinds of problems,'' Latti said Friday.

Sand could have more of an environmental impact on bodies of water than salt or any chemical, according to Peter Coughlan, director of DOT's Maine Local Roads Center.

''Think of thousands of yards of sand that goes into culverts and into streams and rivers, along with sediment and grease and the crud attached to sand,'' Coughlan said.

John Peckenham, senior research scientist at the Senator George J. Mitchell Center for Environmental & Watershed Research, said there is a trend of more chloride showing up in lakes throughout the Northeast -- presumably from road salt.

Also, there is strong evidence of salt in rivers by road crossings.

Peckenham said chemical changes in bodies of water ''may be accelerating the corrosion of concrete structures,'' mostly through changes in the water's acidity level.

''In terms of cumulative effects, we have not looked at that issue,'' Peckenham said. ''What we see in lakes appears to be small enough that large ecological effects are less obvious.

''Now that we are using much more salt on the roads, we would expect to see more pronounced effects.''

The Maine Department of Environmental Protection doesn't monitor salt leaching into water bodies, but it does monitor salt piles throughout the state to keep wells from being contaminated.

Salt and sand-salt mixes are stored in more than 750 registered storage piles. Leaching of sodium chloride from uncovered sand-salt storage has lowered the quality of ground water in Maine.

The department's field investigations have documented more than 150 drinking-water wells in the state that have become contaminated from sand-salt storage.

Josh Katz, an environmental specialist for the Maine Department of Transportation, said he receives up to 20 claims of tainted wells every year.

High sodium concentrations can pose health risks.

''There is an impact to wells, but how sodium chloride effects lakes, rivers and streams is unknown at this time,'' said Erich Kluck, an environmental specialist at DEP.

Salt's impact on aquatic life also is not fully known.

Stephen Norton, a geological-sciences professor at the University of Maine, said he doesn't know of any studies that might suggest that the routine use of road salt harms fish.

A far more pressing problem is the impact that salt has on the state's infrastructure, he said, because it weakens bridges, vehicles and pavement.

Its damage to vegetation and soils is often visible by roads, especially each spring along the Maine Turnpike.

''You can see damage to trees on secondary roads, the browning of white pine needles and red spruce dying,'' Norton said.

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