Road salt's damaging effects prompt smart alternatives to keep highways safe
Washington: Reports indicate that in order to combat environmental concerns, companies in the US are using smarter techniques to minimize the use of salt to make the roads clearer during winter.
Generally, road salt is considered a lifesaver, in regards to keeping the highways clear for vehicles to ply on during winters.
But, the problem lies in the fact that more than 22 million tons of road salt used in the US each year don't just disappear after the snow melts.
Evidence is growing that the salt concentration of streams, lakes and groundwater is steadily increasing.
Salt levels in some places are high enough to harm roadside plants and aquatic life.
Regular road salt is only effective from near freezing to about 15 degrees Fahrenheit. Below that, crews mix in other de-icers like magnesium chloride or calcium chloride, which can work down to well below zero Fahrenheit.
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.
According to a report in Discovery News, to combat environmental concerns, agencies across the country are using smarter techniques to minimize the use of salt while achieving the same performance.
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.
In addition to environmental benefits, using less salt slows its corrosive effects on bridges and cars.
Non-chemical means could also help, according to Kathleen Schaefer of the Minnesota Department of Transportation and the University of Minnesota.
One Minnesota community is testing a pervious pavement surface so that melting snow soaks right through, rather than running off into waterways.
New plow blade designs could be more effective at removing the last layer of snow, Schaefer added.
Even heating the roads with heat tubing underneath the concrete could be an option, especially on bridges, for instance.