The Effects of Road Salt

THE FROG BLOG

The Effects of Road Salt

This winter has been a harsh one and tons of rock salt have been spread over the nation's roads and highways to melt the snow and ice.  Rock salt, or road salt, is inexpensive and it works.  Rock salt is sodium chloride, a natural product that is basically the same as the salt on your dinner table.  However, problems arise when the concentration of sodium chloride becomes too high and the environment is adversely effected. 

The use of road salt to clear ice from the streets began, as an experiment, in the mid twentieth century.  In fact, as recently as the 1940s, only about 5,000 tons were used across the county to control ice on the roads.  These days, however, 10 to 20 tons can be spread across the county in a given season.  Sodium chloride is water soluble, meaning it dissolves into a solution.  Hence, as the snow and ice melt, the road salt is dissolved into it.  The dissolved road salt does not just go away, and therein lies the problem.  The sodium chloride stays in solution and is carried with the melted snow and ice to wherever it runs off to, be it into the soil, the storm drains, or local streams, rivers and other bodies of water, such as your pond.

Unfortunately, the same product that makes our roads safer, can cause environmental damage.  Those of us who live in the Midwest, know the damage the road salt can do.  In the spring, have you ever noticed the tree-lawn grass is brown near the curb?  The dissolved road salt that is absorbed into the ground can cause dieback, interfere with germination, or kill plants altogether.  The same is true of aquatic plants.  When aquatic plants, with lower salt tolerance die back, more salt tolerant species, including nuisance vegetation such as cattails and Phragmites, can take over.  The excess salt in the water can also cause problems for other aquatic plant and animal life.  For example, the increased salinity in the water may decrease the micro-invertebrate population upon which the higher organisms feed, which disrupts the food chain.  Also, the increased salinity of the water can decrease the dissolved oxygen in the water which affects all plants and animals living therein and may cause eutrophication. 

Road salt is necessary to keep the streets clear for public safety.  There are available alternatives, but, unfortunately, many of these are expensive.  Over time, however, this may change and other alternatives may become available.  In the meantime, individuals can take steps to mitigate the use of rock salt.  If you are using rock salt, it works best on a thin layer of snow or ice.  Don't assume using more salt will melt more snow.  Shovel as much of the snow as possible before putting the salt down and use it sparingly.  Also, homeowners might try using sand or kitty litter, when possible, to help prevent slipping.  There are several chemical treatments available as well, be sure to read the labels carefully and apply as directed.  One homeowner's efforts may seem like a drop on the bucket.  But, when many people do a little things to help the environment, big results can be achieved. 

Here's to open waters!

~ The Frogger Blogger
 
References:

http://extension.psu.edu/natural-resources/water/discovery-watersheds/news/2014/sidewalk-salt-and-stormwater
http://www.nbcnews.com/id/7229424/#.Uv4xcCKYbcs
http://www.slate.com/articles/health_and_science/the_green_lantern/2010/02/salting_the_earth.html
http://news.discovery.com/autos/salt-roads-environment-technology1.htm
http://www.stormh2o.com/SW/Articles/8162.aspx
http://www.stormh2o.com/SW/Articles/216.aspx
http://www.newyorkwater.org/downloadedarticles/environmentanimpact.cfm
http://www.dnr.state.md.us/education/envirothon/salt.html
http://www.boston.com/yourtown/news/weymouth/2012/12/salt_in_the_wound_why_you_shou.html
http://www.caryinstitute.org/reprints/report_road_salt_2010.pdf
http://water.greenventure.ca/road-salts-alternatives