Ice and Snow Removal: Using Salt Properly

Image by Nathan Lodermeier

A teaspoon of salt will permanently pollute 5 gallons of water, so proper salt use is important to protect the environment and clean water.

Using Salt: A Summary

Winter in Minnesota means slippery roads and sidewalks, and people using salt to melt the ice for safety. But when the snow and ice melt, the salt that is left behind damages plants and the rest washes into lakes and streams where it accumulates and harms wildlife. Although salt use is unregulated, it poses a real threat Consulting Image Fortin by to water quality — the chloride in one teaspoon of road salt can pollute five gallons of water, and once it is in our water it cannot Quick Tips easily be removed. At high concentrations, chloride: • harms aquatic organisms, • Keep up with the storm • alters community structure in aquatic environments, such as diversity and productivity, • Manually remove as • increases terrestrial bird mortality, much snow as possible • becomes toxic to terrestrial plants. • Be conservative with de-icers Road safety is important, but there are many ways to reduce salt • Pick the right de-icer usage and effectively melt snow and ice. (see the chart on the reverse side) Salt Damage • Don’t use salt in the Brown spots along sidewalks and streets are not only extreme cold. Wait until unattractive, they are also signs that we are harming our a sunny, warm day. You environment. Chloride and sodium in small quantities can use sand to increase

are valuable to plants, but excess amounts create toxic Consulting Image Fortin by traction on slippery areas. conditions, leading to sights like this. How Salt Works Salts are used for their ability to decrease the freezing point of water. The sodium and chloride break apart and slow the water molecules from making bonds that form ice crystals. To be effective the salt and water must be in the right concentration. Therefore, more salt does not mean more melting.

Here is why it works: NaCl

H2O NaCl Na+ H O Sodium Chloride dissolves in water because the Soduium is 2

O- - attracted to the negatively charged Oxygen. The Chloride Cl is + - + + H O Na H O H2O Cl H2O H H H+ H+ 2 2 attracted to positively charged Hydrogen molecules O - . The Sodium H2O H O Chloride breaks apart and is then “dissolved” by the water molecules. 2 Shovel! Shovel! 1 2 Salt is more effective after Break up ice with an snow and ice have been ice scraper. Once you removed (shovel, snow have removed the blow, plow and/or sweep). snow and ice you may need to apply a de-icer or sand for traction. Image by Fortin Consulting Image Fortin by Image by Fortin Consulting Image Fortin by Less is better: Avoid scenes like this: 3 4 • Do not trust the labels. More salt Sweep up extra salt or does not mean more melting. sand. When it is visible • Ensure you follow the “practical it is only doing harm. melting point” not the “eutectic Reuse it or throw it in temperature”. the trash. • See the guide below to choose a de-icer and the proper quantities

Image by Fortin Consulting Image Fortin by to apply.

Quantities Melting Agent Freezing Temps Environmental attributes Sodium Chloride 15o F Cyanide and significant negative for a de-icer: (table or rock salt) environmental effects Calcium Magnesium 22o-25o F Less toxic than Sodium Chloride Less than 4 pounds per 1,000 Acetate (CMA) square feet. 1 pound of salt Calcium Chloride -20o F No cyanide, lower quantities needed is approximately a heaping Urea 20o-25o F Excessive nutrients, less corrosion 12-ounce coffee mug. Other options when it’s too cold! Sand No melting effect Accumulates in streams and lakes Image by Fortin Consulting

Learn More: Minnesota Pollution Control Agency. At: http://www.pca.state.mn.us Minnehaha Creek Watershed District. At: www.minnehahacreek.org