If you’ve spent much time in a place that experiences snowy or icy winters, then you’re probably familiar with road salt, commonly used to melt ice by lowering its freezing point in order to dissolve it back into water. Although it’s long been a common solution used by states and cities for quickly and affordably deicing roads (the U.S. Geologic Survey claims deicing accounts for 43 percent of total manufactured salt in the U.S.), a growing body of research has revealed a list of environmental and safety concerns related to its use.
The impact of road salt runoff
Road salt (aka sodium chloride) is 40 percent sodium, 60 percent chloride, and a smattering of other components: ferrocyanide (often used as anti-caking agent), phosphorus, and iron. The problem? Road salt and its unnatural additives are making their way into our natural environment.
A loss of biodiversity
Runoff from road salt can end up in our streams and lakes, resulting in a loss of biodiversity, with abnormally high levels of salt killing off certain species of fish, insects and other native organisms. Scientists have also found that roadside plants have significantly higher levels of salt than their counterparts, making them more susceptible to takeover from invasive species. Many bird populations are also at risk because consuming even a tiny amount of salt can be toxic.
An increase in animal-auto collisions
Researchers are also finding that some animals (think deer and moose) are drawn to salty roadside plants, putting them, and any humans they might come into contact with, at an increased danger for roadside collisions. Animals drinking snowmelt to relieve thirst may also experience the side effects of salt toxicity: dehydration, confusion, and weakness, among other symptoms.
A decrease in drinking water quality
High levels of chloride and other contaminates found when road salt gets into a water system pose a risk in quality to all animals, plants, and humans that depend on that particular water source. Individuals who are on low-sodium diets or who have high blood pressure must be especially careful since there may also be taste and odor issues in water with elevated chloride levels.
Accelerated corrosion and rust
Chloride also quickens the speed at which things corrode — from the concrete on bridges, to the decking of a parking structure, to the lining of your brake pads. Moreover, repeated exposure to salt can cause a vehicle to rust, especially on its underbody. Some estimates put corrosion protection practices for highways and the automobile industry at between 16 and 19 billion dollars per year.
How to stay safe
So what can you do? For starters, try investing in a good shovel and use less salt on your driveway and sidewalk. And whenever possible, try to avoid driving immediately after road salt is put down. Visiting a car wash with an under-spray function during the winter months can also help minimize your car’s exposure to corrosive elements.