Did you know that many Minnesota lakes and rivers are contaminated with chloride? This toxic chemical comes from the salt and deicers we use to keep ice off our roads in winter. Although they make it easier to get from point A to point B, we pay a big environmental price for using these chemicals to melt the ice on our roads.
Chloride is virtually impossible to remove from a waterbody. Once it’s there, it’s there for good. And just one teaspoon of salt contains enough chloride to pollute five gallons of water forever.
In recent years, public works agencies have begun providing their snow plow crews with special training and tools to minimize this type of pollution. You can do your part at home by following these simple tips for pollution-free snow and ice removal.
Shovel, Scrape, Repeat
The best way to remove snow and ice is the old-fashioned way: with elbow grease. Shovel early and often during a snowstorm so that the snow doesn’t have time to become compacted and/or turn to ice. It might sound obvious, but the more snow you remove by shoveling or snow-blowing, the less ice you’ll have to deal with later.
If you’re finding that your old metal push shovel with the bent, rusted edges isn’t cutting it anymore, it might be time to add some new tools to your arsenal. Your local hardware store is likely to carry a variety of push shovels, scoop shovels, ice chisels and ice scrapers. There are many types of snow, slush and ice, so having a couple of different tools on hand never hurts.
If It’s Too Cold, Don’t Use Salt
It’s important to note that winter weather in Minnesota follows a cruel, predictable pattern: the relatively warm temperatures during a snowstorm are typically followed by a big temperature drop. Unfortunately, this often renders salt and deicers useless.
Salt and deicers only work in certain temperature ranges. Traditional road salt (sodium chloride) doesn’t work below 15 degrees F. Other products made of magnesium chloride, calcium chloride or urea have different melting temperatures, but the bottom line is that if it’s too cold, none of them will work.
When you think you need to apply salt, check the temperature first and read the label on your deicer product carefully to make sure it will work under the relevant weather conditions.
Use Sand to Provide Traction When It’s Too Cold
If you have a walkway covered in ice and it’s too cold for your salt or deicer product to work, you might be better off using sand.
Sand doesn’t melt the ice. Its job is to sit on top of the ice to provide traction. This makes it safer to walk or drive across icy pavements. Use it sparingly, however, as sand is also a pollutant. Much like road salt, it gets washed into stormdrains in the spring and ends up adding sediment to rivers and lakes. You can help prevent this by sweeping up leftover sand and saving it for re-use.
It’s worth noting that mixing sand and salt together is practically useless, as they serve completely different purposes. Sand only works if it sits on top of the ice. If it’s warm enough that the salt is working, then the sand isn’t doing anything besides sitting on wet pavement.
If you’ve cleared away all the loose snow and ice and it’s warm enough for the salt to do its job, then go ahead and apply it. Just remember that more salt does not equal faster melting — just more pollution and wasted money.
Use as Little Salt as Possible
More salt does not equal more melting. So if you need to use salt, try to apply the proper amount of product for the size of the area you’re treating. There’s an easy way and a hard way to calculate this.
First, the easy way: shoot for a 3-inch spread between salt granules. That’s it. Try taking a few measurements initially to see how far your spread is; afterward, you’ll learn to eyeball it. If you can create a good spread pattern and memorize what it looks like, it will help you ensure that you use a reasonable amount of deicer every time. If you’re willing to spend $10-$20, a hand spreader can make the job a lot easier.
If you want to be even more exact, try to apply the equivalent of 4 pounds of salt or deicer per 1,000 square feet of pavement. Use a tape measure to figure out the square footage of the area you’re treating and then use this ratio to calculate how much salt or deicer you should use for that area.
And remember: If it’s a warm day and the sidewalk is wet, don’t use any deicers. The sun is already doing the job for you, and throwing salt onto the ice isn’t going to hurry the process; it’s just going to send deicer down the stormdrains.
Salt and Deicer Comparison
Virtually all salt and deicer compounds and blends are damaging to the environment as well as harmful to concrete, metal and other materials. Some will work in lower temperatures than others. Here is a comparison of some common deicers and their various properties.
|Melting Agent||Lowest Melting Temp.*||Things to Know|
|Urea||20°F||Promotes algae growth in waterways; over-application can harm plants; pet-safe; slow-acting|
|Sodium Chloride (NaCl)||15°F||Harmful to plants; harmful to concrete; very corrosive to metal; cheap and abundant|
|Magnesium Chloride (MgCl2)||-10°F||Harmful to plants; corrosive to metal; relatively high cost|
|Potassium Acetate (KAc)||-15°F||Can cause surface slickness; lowers oxygen levels in waterways; biodegradable; relatively high-cost|
|Calcium Chloride (CaCl2)||-20°F||Corrosive to metal; leaves slimy residue; less harmful to concrete|
|Sand||No melting||Provides traction only; potential pollutant; can be swept up and re-used|
*Refers to pavement temperatures.
Master the art of pollution-free snow and ice removal with our “Improved Winter Maintenance” video on YouTube:
Minnesota Pollution Control Agency
10 smart salting tips that protect Minnesota waters (news release)
Road salt and water quality (web page)
Environmental concerns about road salt (web page)
For our lakes’ sakes, stick to a low-salt diet (article)
Chloride and Our Water: Monitoring the Mix (video)
Nine Mile Creek Watershed District
Clean Water Minnesota
Using Sidewalk Salt Responsibly (web page)
Be Salt WIse! (website)