Dealing with Ice

It’s that time of year again! Time for early morning snow shoveling and freezing evenings tossing de-icing salts on your front steps.

Safety is paramount. When we toss rock salt on our front steps, we don’t mean any harm. Really, we just want to protect ourselves and our families from a nasty fall. But deicers have all kinds of unexpected effects, impacting pets, plants, and even our larger environment.

After the snow melts, that stuff we all spread on our front steps has to go somewhere. Often, snowmelt or rain will wash it into our sewer system or into our yards. Either way, de-icing compounds end up in ground water. Ultimately, they make their way into our water systems. So, what’s in deicers and what effects do they have?

Many commercially available deicers are chloride-based. These include sodium chloride (i.e. rock salt), calcium chloride, potassium chloride and magnesium chloride. They often aren’t the best choice for deicing for several reasons:

Pets

No chloride-based deicer is considered safe for pets. Sharp deicers like rock salt can cut pets’ unprotected feet or cause chemical burns. They can also be toxic even in the correct dose. Sometimes, symptoms are less severe, like stomach upset, but a relatively small amount of salt (especially for tiny pets) can become lethal.

Plants

Chloride-based deicers also negatively impact plants, though to different degrees. Since chloride-based deicers are salts, they can create salt build up in soil and, at worst, prevent growth entirely. That’s how we got the phrase “salting the earth.” Throwing salt on agricultural fields became a tactic to prevent enemies from growing necessary crops during wartime. Salt pulls water from root systems, inhibiting or preventing growth.

Not all chloride-based deicers impact plants the same way, however. Potassium chloride, in the correct dose, is a fertilizer. So, while it can still cause chemical burns and damage root systems, it’s less likely to harm plants than calcium chloride or sodium chloride, which are both very corrosive.

Environment

The most common environmental concern when using chloride-based deicers is contamination of ground water and other water systems. Just how salt build-up in soil can be dangerous, so can salt build-up in water. Excessive salt in any body of water affects the composition of the water and all the creatures living in that water. As water salinity increases, oxygen levels in water decrease. There are fish and other animals built to live in saltwater, but they all have their limit (and you aren’t going to find saltwater fish in Iowa, anyway!).

The impacts of chloride-based deicers don’t stop there. According to the University of Minnesota Extension office, just one teaspoon of salt can pollute 5 gallons of drinking water. Groundwater salt pollution can have a particular negative effect on private wells, which don’t have the same treatment capacity as municipal water facilities, changing the water’s flavor and creating problems for the well’s owners. That’s a concern for municipal water treatment plants, too. Salt can be tricky and expensive to remove from a city’s drinking water.

How do we fix this? Like most problems, there’s no quick and easy, one-size-fits-all answer. Sometimes we need to prioritize safety and that can mean using chloride-based deicers. However, there are some ways to mitigate concerns.

If your pets must walk through chloride-based deicers, try winter booties (good for preventing frostbite on their paw pads, too). You can also clean their feet with a damp rag when they come inside. Perhaps most importantly, keep an eye out when they’re around deicers, especially if your pet likes to eat things off the ground.

There are also more environmentally friendly options. The most common is calcium magnesium acetate (CMA). Since CMA isn’t a salt, it avoids a lot of our salty problems. CMA is also considered less toxic than other options. As it breaks down, CMA disperses into calcium and magnesium, which can benefit soil, and the acetate biodegrades into carbon dioxide and water. Too much of a good thing is never good however, and CMA still shouldn’t be overapplied.

Applying deicers correctly can also reduce negative impacts. Many people, with the best intentions, over-apply deicers. Instructions on the bag should provide guidance for best practice.

If you can live with a little ice, you can also use non-deicing substitutes. Options like sand or kitty litter provide traction when walking over icy surfaces. They don’t melt the ice, but if the situation isn’t so severe, they might provide you all the traction you need. Best part, they can be swept up (and even reused in some cases) once the weather warms up.

Curious to learn about the salt levels in water bodies near you? Request a FREE Salt Watch kit from the Izaak Walton League — they’ll send you everything you need to find out whether road salt pollution is a problem in your local stream.