By ALISON MITCHELL
Executive Director, New Jersey Conservation Foundation
In winter weather, cleaning roads, walkways and parking areas usually includes applying a lot of salt. When something is cheap and plentiful, we tend to be careless about how much we use. While rock salt is very effective at melting snow and ice, it comes at a steep cost.
The amount of salt used on roadways has increased dramatically over the years. The practice started in the 1940s and ’50s, when about 5,000 tons were spread annually. We now use about 20 million tons each year, roughly 123 pounds for every American.
Clearing roadways for emergency vehicles and other essential travel makes sense, but too much salt in the environment is toxic, and the damaging impacts continue well after winter ends. It harms fish and aquatic insects like dragonfly larvae that control mosquitoes, as well as other invertebrates like crayfish and freshwater mussels. It impacts entire food chains, causing harm to birds and other animals.
Excess salt accumulates on a road, killing plants and harming wildlife that eat the salt crystals. Treated roads also attract animals like deer, who love licking up the salt and don’t mix well with traffic.
High salinity can also contribute to harmful algal blooms and low dissolved oxygen levels in lakes and rivers when the salt dissolves and rain carries it into these waterways. The problem is even worse in highly urbanized areas, where large amounts of impermeable land cover lead to faster runoff.
Road salt also harms humans more directly. Surface and groundwater become contaminated, with salt infiltrating drinking water reservoirs and wells. Water becomes more expensive to treat and can even develop a temporary salty taste. High sodium levels in drinking water can also affect people with high blood pressure.
Salt is highly corrosive, and can wear down homeowners’ pipes and public infrastructure like treatment equipment. In large quantities, its corrosive quality also affects cars, bridges, and roads, resulting in about $5 billion in U.S. repairs. And once the salt seeps into our environment, there are no biological processes that will remove it.
All of this means that we really need to pull back on indiscriminate use of salt. How do we do that?
To start, shovel snow before using salt and before the snow turns to ice, reducing the need for de-icing. If you must use salt, moderation makes a difference. You need less than you think: a 12-ounce coffee mug holds about one pound of salt, enough for a 20-foot driveway. For the most effective coverage, spread the salt so there’s about 3 inches of space between granules and sweep up excess from dry pavement.
There are also alternative treatments. Since 2012, Rhode Island has been applying a brine solution to roads before snow events, reducing the total amount of salt applied by 30 to 50%. Known as anti-icing, this practice prevents the formation of frost on pavement.
Sand used in moderation can help with traction. One reason it’s not more popular is that after the snow or ice melts, the remaining sand can wash into catch basins or adjacent waterbodies. Businesses can revise snow removal contracts to pay according to how much area is cleared, rather than how much salt is applied. Other alternatives include adding biodegradable substances like pickle juice to the road salt.
Ask your municipality to commit to alternative methods to keep roads clear and pave the way for a tailored approach to de-icing in an environmentally conscious manner without risking driver safety.
For information, visit NJ Salt Watch, a free science program funded by the New Jersey Department of Environmental Protection and managed by The Watershed Institute. It provides residents, businesses and municipalities the opportunity to measure and share impacts of road salt on local streams and lakes.
Learn more and register at thewatershed.org/njsaltwatch.
