Salt's Effects Prompt Tech Alternatives (page 2)


Salt use has climbed steadily since World War II, with road salt representing 65 percent of total U.S. salt sales.

"People simply expect to drive on dry pavement four hours after a snowstorm. Our expectations are very, very high," Baker said.

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All this salt leads to briny conditions come spring. "At the peak, when you have a big melt, you can get concentrations about one-third that of seawater," Baker said.

It is the chloride ions that do much of the environmental damage. The chloride ions dehydrate plants, can kill small aquatic organisms and reduce water circulation in lakes that helps to aerate the water. Chemicals without chloride are available, such as potassium acetate, but these are several times more expensive than salt.

To combat environmental concerns, agencies across the country are using smarter techniques to minimize the use of salt while achieving the same performance.

"The crews need to understand that if 300 pounds per lane mile is good, 600 pounds is not better," Hanneman said.

New techniques include "anti-icing," in which salt solutions are sprayed down before the storm. This prevents the ice from freezing to the road in the first place, effectively making a non-stick coating on the roads.

Wetting the salt before applying also keeps more on the roads where it's needed, instead of bouncing off onto roadsides.

Smart plow trucks equipped with computers track storm conditions, pavement temperatures, and local weather to constantly update the optimal amount of salt that should be applied. The state of Indiana implemented this approach last winter, saving 228,000 tons of salt, and more than $13 million dollars in salt and overtime costs, according to a state report.

In addition to environmental benefits, using less salt slows its corrosive effects on bridges and cars.

Non-chemical means could also help, Schaefer said. One Minnesota community is testing a pervious pavement surface so that melting snow soaks right through, rather than running off into waterways.

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New plow blade designs could be more effective at removing the last layer of snow, she added. Even heating the roads with heat tubing underneath the concrete could be an option, especially on bridges, for instance.

"I think we need to take an innovative approach and say, we don't have one silver bullet," she said.

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