It’s winter. The weather forecasters are predicting a snow storm, maybe possibly freezing rain at any time. You run to the shed or garage to get your rock salt out and start pouring it out in buckets all over your driveway and sidewalks. Makes for less work later, right? But is that the most effective approach? And what does all that salt mean for the environment?
It’s estimated that 40 percent of the country’s urban streams have chloride levels that are so high they pose risks to aquatic wildlife. Those severely impacted include amphibians — such as frogs and salamanders — crustaceans, fish, and aquatic plants. The primary reason for this chloride? The oversalting of roadways, driveways, and sidewalks in the winter months. In 2014, more than 22 million tons of salt (sodium chloride) were scattered on U.S. roads annually — 137 pounds of salt for every American. Millions more are spread by private property owners.
Once spread on roadways and sidewalks, these highly concentrated salts start to do their work not just on snow and ice, but the environment around them. Plants and trees near road salt can become dehydrated and even die, creating desert-like conditions that make it harder to absorb water and encourage runoff and pollutants to enter the watershed. Likewise, many animals congregating at these deposits for much needed minerals are hit by cars and others, such as domestic pets, can become sick from ingesting salt and face the potential for vomiting, convulsions, and kidney damage.
After the storm passes and the salt dissolves, it gets carried away through runoff and deposited in these surface water streams, rivers, and lakes. It also absorbs into the ground and permeates the groundwater underneath us. Millions of Americans rely on local streams for their drinking water. And while we mostly rely on WSSC for treating our water, even the most advanced water treatment plants are not equipped to filter out this excess salt. This means that salt ends up back into your pipes and in your tap water, a health risk especially for individuals on salt-restricted diets. Excess salt can also easily corrode your car and break down concrete surfaces, such as driveways. With all these negative effects, Canada has actually categorized road salt as a toxin and placed restrictions on its use.
Salt is quite effective in preventing ice from forming, as it lowers the freezing temperature of water so ice and snow can be removed more easily. As a result, it takes surprisingly little to adequately protect your sidewalks and driveways. You don’t actually need to feel it crunching underneath you to know the salt is doing its job. It only takes 12 ounces of road salt (about the size of a mug) to cover a 20-foot driveway (or 10 sidewalk squares) for instance. Make sure to space grains out for full effectiveness. Using a lawn spreader can help evenly spread de-icer and prevent it from clumping. That said, adding even more than the recommended amount of salt on a surface does not help in making the snow and ice melt faster, or prevent you from needing to shovel.
Don’t simply just rely on laying salt down to clear your property. Montgomery County Government recommends a three-step approach to winter weather and clearing sidewalks and driveways. First, shovel right away when winter weather hits and before snow turns into ice. Second, know when to treat. Check the temperature and weather conditions. If the sun is out, let it help you melt the ice and snow. If temperatures are forecasted to rise, de-icing products might not even be necessary. Otherwise, read the label on your de-icing products for correct usage, as weather conditions can impact their effectiveness. Salt de-icers, for instance, become ineffective when the temperature drops below 15°F. Also, only apply these products to surfaces that are already icy, or you’re just wasting your money and negatively impacting the environment for no reason. Finally, at the end of the weather event, make sure to sweep and clean up any salt, sand, or any de-icing product that has not dissolved. These can be used for the next storm.
Instead of using pure road salt, or sodium chloride alone, consider using it mixed with sand. Many municipalities use a mixture of 30 percent sand, 70 percent salt. The sand helps eliminate the “bounce” factor of the salt when it hits roadways and sidewalks, allowing for less salt to be used but with the same overall effect. Scattering sand on icy surfaces can also provide temporary traction and reduce slipping dangers, especially if temperatures are expected to quickly rise after the storm.
Other alternatives that have proven beneficial to homeowners and road crews alike are mixing salt with cheese brine and even sugar cane molasses. These alternative mixes help prevent freezing at lower temperatures and helps road salt to stick better and reduce its corrosive qualities. Likewise, calcium magnesium acetate, while more expensive than regular sodium chloride de-icers, is considered a lot less environmentally harmful. While kitty litter is often used like sand for traction, its habit of clumping and not dissolving makes it not an ideal choice.
Whatever you use, do however watch out for ice solutions labeled as “eco-friendly” or “pet-friendly” as, often times, these products still contain salt that can harm animals and plants.
Environmental organizations, concerned about the amount of salt being used in communities, are seeking citizen science volunteers to pinpoint exactly how bad the problem is. The Izaak Walton League, for example, has a Winter Salt Watch program. Trained volunteers use a kit with chemical test strips to monitor waterways throughout the winter season. Results are reported to a national database and are used to communicate with decisionmakers. For more information, visit Winter Salt Watch at www.iwla.org/water/stream-monitoring/winter-salt-watch.
Another way to encourage less salt use in the community is by alerting our County and State Departments of Transportation as well as our legislators to the impacts of road salt. These agencies can work with their drivers on best practices for road salt use, hopefully resulting in less being used.
For more ideas on how to help, and educate, individuals on the use of salt, visit www.iwla.org/water/stream-monitoring/winter-salt-watch/what-you-can-do.
[Jennifer McGuire Cox is a naturalist and certified Maryland Master Naturalist; she lives on Belton Road.] ■
© 2021 NFCCA [Source: https://nfcca.org/news/nn202112h.html]