Alternatives to Road Salt
By Shawn Dell Joyce
Winter weather has struck hard this year, and many people and municipalities are pouring on the road salt. According to the National Research Council (NRC), we Americans dump 8 million to 12 million tons of salt on our roads per year.
Massachusetts, New Hampshire, and New York report the highest level of salt use, with New York weighing in at 500,000 tons per year. The New York State Department of Transportation requires a road-salt application rate of 225 lbs. per lane-mile for light snow and 270 lbs. per lane-mile for each application during rapidly accumulating snow.
When you consider that there are approximately 6,000 miles of paved roadways near New York watersheds, you begin to see how all that road salt adds up. Some roads may get up to 300 tons of salt per lane-mile each year. Recently, many scientists have begun to study the effects of so much road salt on ecosystems, water quality, public health and road quality. Here are a few things you should know before your break out that sodium chloride (NaCl) the most commonly used deicer:
–Salt destroys soil structure by killing some bacteria. This allows more soil to erode into streams, taking the salt with it. Salt erosion contaminates drinking-water supplies to levels that exceed standards.
–Salt doesn’t evaporate or otherwise get removed once applied. So it remains a persistent risk to aquatic ecosystems and to water quality. Approximately 55 percent of road salt runs off with snow melt into streams, with the remaining 45 percent infiltrating through soils and into groundwater aquifers according to a 1993 study.
–Salt slowly kills trees, especially white pines, and other roadside plants. The loss of indigenous plants and trees on roadsides allows hardier salt-tolerant species to take over.
–Salt can change water chemistry, causing minerals to leach out of the soil, and it increases the acidity of water, according to Dr. Stephen Norton, a professor of Geological Sciences at the University of Maine.
–Salt cracks animals’ paws. House pets are particularly susceptible.
–Road salt seeping into drinking water changes its flavor, and supplies the excess dietary sodium associated with hypertension.
–Salt corrodes metals like automobile brake linings, frames, and bumpers, and can cause cosmetic corrosion. Auto makers pay almost $4 billion a year in efforts to prevent this.
–Salt can penetrate concrete to corrode the reinforcing rods of bridges.
Canada is considering classifying conventional deicers as toxic substances under the Canadian Environmental Protection Act. California and Nevada restrict road salt use in certain areas to reduce damage to roadside vegetation. Massachusetts is using alternative deicers to prevent contamination of drinking water. New York is considering doing the same to protect New York City’s watershed.
There are alternatives to sodium chloride that are relatively harmless to the environment and still get the job done. Calcium magnesium acetate (CMA) and potassium acetate (KA) are two such alternatives currently available. They are much more expensive than salt, but if you factor in the loss of wildlife, soil erosion, water quality and corrosion, these alternatives start to look like a real bargain.
Shawn Dell Joyce is the director of the Wallkill River School of Art in Montgomery. www.WallkillRiverSchool.com
Tags: Shawn Dell Joyce
January 24th, 2012 at 1:06 am
Hi Shawn,
Read your article in ”the Zest of Orange.” I’ve worked in the field of public health and environmental engineering for over 30 years so of course the article caught my attention. I have a few observations on the issue:
• You indicate that research on the effects of road salt on ecosystems, water quality, public health and road quality is fairly new, however, this research to my knowledge has been ongoing for over 50 years.
• In bygone days road salts were applied with the idea that more was better. Today, based on the research mentioned above road salts are applied at a rate determined by the size of the surface area to be treated, atmospheric temperature, and precipitation conditions. The economic savings derived from modern day practices is also a strong incentive.
• As you probably remember, in the past road salts were stored in piles exposed to the elements and erosion from the salt piles was found to result in the contamination of surface and underground water. Through enforcement of nationwide environmental regulations to eliminate this major source of surface and underground water contamination salt piles are now housed.
• You mentioned the possible use of alternative products to the sodium chloride conventionally used. The last time I checked the cost difference of the alternative products to sodium chloride was anywhere from 10 to over 20 times; except in a few critical environmentally sensitive areas (such as drinking water reservoirs) the high cost is obviously an extremely huge deterrent to the use of alternative products. The economic savings derived from preventing the washing away of salt is also a strong incentive.
• The implementation of nationwide stormwater management regulations over the past 10 years requires the collection and treatment of runoff from impervious surfaces. On privately own property these regulations deal mainly with new construction or modifications to existing sites. The regulations also deal with existing municipally owned infrastructures (e.g., highway garages, roadways, storm sewers).
Finally, another recently (within the past 10 to 15 years) discovered major source of underground water sodium contamination is from individual household water softeners that use salt to treat hard water conditions commonly found in water obtained from wells. The wastewater from these softeners is typically discharged into a subsurface drywell (an underground structure that in turn disposes of wastewater by dissipating it into the ground where it eventually merges with the local groundwater). In the Stamford, Connecticut area this became so great a problem that local laws were implemented to eliminate the practice (existing and proposed). Here in New York new water softener drywells are prohibited.
Thanks for posting this topic.
Joe
January 25th, 2012 at 10:07 pm
In urban areas with underground electric systems (notably New York City), road salt is the culprit behind manhole explosions — as a piece I wrote in The Huffington Post explained. Here’s the link:
http://www.huffingtonpost.com/tom-bisky/when-manholes-explode-new_b_663880.html