Student Voices Series: Road salt’s unintended consequences

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The Minnesota Environmental Partnership is proud to feature the following post as part of a series of columns as part of a Student Voices Series issues. This is part of a continuing collaboration with Macalester College’s Geography Department and its students.

Snowfalls are integral to Minnesota winters. From November to April, snow becomes an unavoidable part of life. People who live in snowy climates have adapted, utilizing conveniences such as road salt to reduce the amount of ice that builds up on pavements. Applying road salt can make roads safer for driving during wintery conditions.

However, road salt damages water sources. It contaminates both drinking water and groundwater, increasing chloride levels. These increased chloride levels are not naturally filtered out of water systems, they can only be reduced through dilution. Road salt poses a threat to human health and environmental health. To name a few hazards, high salt levels found in water can cause hypertension for at risk individuals, disrupt plant growth, and reduce species diversity through the establishment of species with a high salt tolerance  States, counties, municipalities, business owners and private citizens must all develop new ways to be smart about the application of road salt in order to prevent damaging environmental impacts.

Vast quantities of road salt are used in Minnesota each winter, and it has a tremendous effect on the state’s water systems. The Minnesota Department of Transportation used, “267,860 tons of [salt] and 2,544,466 gallons of salt brine on 12,000 miles of state highways” in 2012. All of this salt works its way into local lakes, rivers, and streams. The Minnesota Pollution Control Agency states, “It takes only one teaspoon of road salt to permanently pollute 5 gallons of water. Once in the water, there is no way to remove the chloride, and at high concentrations, chloride can harm fish and plant life.” The Star Tribune reports that road salt use in nine communities would have to be reduced by 71% in order to return Shingle Creek, a watershed that flows under roads and behind shopping malls in the western suburbs of Minneapolis, to healthy salt levels.

Without some sort of melting agent, roads would often be impossible to navigate during winter months, and travellers would be much more prone to accidents. Some road salt or equivalent melting agent is needed to protect the safety of Minnesota drivers. Eliminating road salt would be just as bad as over-salting. A balance must be struck that protects the safety of citizens and does not cause more pollution. The critical question remains: how can road salt be applied in a more efficient and environmentally friendly manner?

 Changing the current practices of indiscriminately salting pavements, driveways, and roads is a necessary way of amending the snow removal system.  The Minnesota Pollution Control Agency  and the EPA  recommends multiple methods for smarter snow and ice removal. Transportation departments can follow and enforce these steps:

  • Shovel and plow before salting.
  • Street sweeping, an alternative that reduces the amount of road salt needed to de-ice roads.
  • Only use salt when temperatures are above 15 degrees Fahrenheit. Salt does not work when the temperature drops below this point.
  • Limit the amount of salt used. Adding more does not melt ice faster.
  • Pre-wet the salt, which increases its ability to melt ice, so less is required.

Changing awareness of when and how much road salt to administer is an important step toward reducing the amount of salt used in Minnesota.

State, county and municipal transportation departments must practice additional methods to protect the environment. Another way to reduce the amount of road salt used is to investigate other options. Milwaukee, Wisconsin is one city that has explored alternative methods such as sugar beet juice, and more recently cheese brine ( When mixed with road salt, cheese brine speeds up melting and helps salt stick to the road. Salt usage can be reduced by 30%-40%.  Road salt usage needs to continue to go down, a 30% decrease is not enough. However, it is an important first step and a major improvement. Utilizing alternative materials in addition to road salt could vastly minimize the environmental and economic repercussions of road salt.

Icy winter roads can be dangerous. Road salt makes roads and pavements more navigable and keeps everyone safer. However, the damage that road salt does to the environment is too destructive for it to be used indiscriminately, without an innovative plan to minimize the amount of salt required to clear the roads. A balance can be created, by using both road salt and more environmentally friendly alternatives such as cheese brine and sugar beet juice. Professional snow removal crews need to be reeducated on how to effectively use the least amount of road salt needed to de-ice the roadways.

Changes need to be made in how Minnesotans use road salt. Communities can follow simple guidelines to prevent further pollution of Minnesota’s lakes, rivers, streams, and groundwater. For every teaspoon of salt that you keep from reaching the street, gallons of water remain pristine. Contact your local municipalities and express your concerns about the over use of road salt, and ways to be smarter about its application You can help improve the way road salt is used in Minnesota.

Alyssa Heitfeld is an English major at Macalester College. She is interested in Environmental Politics and has taken several classes in the Environmental Studies department.

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