Is There A Greener Way To Fight Ice?

Should we rethink salting our roads in the winter?

The amount of salt applied to our roads after big snow storms to combat ice increases dramatically year by year. Road salt application and plowing systems are the traditional primary snow removal methods, necessary for the safety of pedestrians and minimization of car accidents. The rise in salt application is due mostly to its low cost, ease of application, and high effectiveness. Yet recently discussions have arisen about the harms of it on our ecosystem, as runoff from roads and sidewalks has been found to unnaturally increase lake and river salinity, harming local wildlife populations. You will come to learn, however, that there is not one perfect solution, and all alternatives have challenging pros and cons.

The harmful effects of road salt: 

Although road salt is a useful tool for winter safety, it is not without its flaws. Studies show that the road salt that is dumped casually on the roads by your house can travel up to 50 meters through soil. It has also been shown to wash into waterways after a heavy rainfall. This heavily contaminates our drinking water as well as water ecosystems. High concentrations of the sodium chloride in road salt can be fatal to many species of invertebrates. Prolonged exposure to high concentrations of chloride has been known to cause infertility in fish. In humans, sodium chloride can cause stomach problems, skin irritation, and elevated blood pressure. Road salt has also been known to cause soil degradation by disrupting its structure and chemical composition. The sodium and chloride ions that are released when road salt enters the soil leads to the displacement of key nutrients. This directly affects plant life by either stunting their growth or killing them. Road salt also leads to a negative effect on infrastructure. Salt can travel through the air via salt sprays. This causes the accelerated corrosion of concrete and steel in buildings. Eventually, this leads to premature structural damages in buildings and bridges

Is salting our roads a necessity?:

Road salt is known for its detrimental environmental effects, so why do we keep using it? Public safety is the first issue that comes to mind. Icy roads and walkways are extremely dangerous. Studies show that approximately 30% of car accidents in Canada are the result of icy roads. Canada’s winter months are long, and people need to be able to get to school and work. Road salt is a cost effective and efficient way to reduce ice on the roads and ensure safety. The chemicals in road salt are what breaks down ice, and that allows for safe transportation for Canadians. With that being said, are there equally effective alternatives? 

Alternative methods to rock salt:

There are many alternatives to rock salt which are being studied at the moment due to the pressing nature of concerns about rock salt (not just its effect on water salinity) having widescale effects from; corrosion of infrastructure, damage to vehicles, impact to vegetation, and increased waste products. Alternatives are typically broken down into three categories, all with unique pros and cons. This piece is not trying to make an argument as to which is the best, merely start discussion about the complexity of this topic.

Chloride deicers: 

These are most commonly used, and include calcium chloride, magnesium chloride, and pre-treated sodium chloride (“treated salt”). They are all highly effective with lower effective temperatures than traditional rock salt, and require lower application rates, contributing less chloride to the environment. It is also less corrosive to metals and can be coloured to ensure mental comfort in knowing a surface has been treated. However, they still contribute a good deal of chloride to the environment, and are all more expensive than rock salt.

Acetate deicers:

There are a great number of these deicers, with the most common being calcium magnesium acetate. These require fewer applications because they have a residual effect, and limit corrosion of metal. They also completely eliminate chloride, and have an added bonus of keeping the snow lighter, which aids in mechanical snow removal processes. However, these deicers have a great number of drawbacks. They are expensive, have a limited range of temperature when they are effective, and perform best when applied before it snows. They also still affect groundwater, as they release acetate ions which increase biological oxygen demand, and its mining has huge environmental impacts.

Agricultural byproducts (Organic deicers):

These products may seem the most appealing alternative to road salting, and include beet juice, whey, and wheat-based starches; they are products of already occurring processes. They are typically added to chemical deicers, and are part of anti-icing, meaning they are applied before a storm to prevent the formation of ice. However, just because an alternative is part of a natural process and appears more eco-friendly and environmentally-conscious, this is unfortunately not the case. Although agricultural by-products do have pros, like being non-corrosive, increasing the efficiency of salt when used in conjunction, contributing less chloride to the environment, and being a by-product of existing processes, there are still harmful downsides. These organic deicers can contribute to oxygen depletion and eutrophication (excess of nutrients in water due to land runoff, creating suffocating plant life and killing animal life due to lack of oxygen). The degradation on land can lead to anaerobic soil conditions. Additionally, there are definitely some concerns about the smell that could arise.

Local attempts to use alternatives:

Numerous local municipalities have tried out alternatives to traditional rock salt. Seven out of thirteen municipalities in the Lake Simcoe watershed (north of Toronto, near the town of Barrie) have incorporated treated salt into their practices. Aurora has completely switched to using Thawrox (a type of treated salt), reducing their application rates significantly. Several municipalities have also tried incorporating agricultural by-products into their mixes, but found the drawbacks made it too unsuitable.

Road salt is just one of the many things humans use to make our lives easier, and it is hurting us in the long run. Although road salt feels like a winter safety necessity, is it becoming more trouble than it’s worth? As road salt continues to cause harm to our ecosystems and our infrastructure, should Canadians be turning towards alternative methods?

Resources:

Alternatives to salt: What else melts snow and ice?. Sustainable Technologies Evaluation Program (STEP). (2020, April 16). https://sustainabletechnologies.ca/home/urban-runoff-green-infrastructure/pollution-prevention/road-salt-management/alternatives-to-salt-what-else-melts-snow-and-ice/ 

Environmental Protection Agency. (2020b, November). Winter is Coming! And with it, tons of salt on our roads. EPA. https://www.epa.gov/snep/winter-coming-and-it-tons-salt-our-roads 

Tenneti, A. (2022, December 17). Looking into road salt use, harms, and alternatives. NiCHE. https://niche-canada.org/2022/12/19/looking-into-road-salt-use-harms-and-alternatives/#:~:text=Environmental%2C%20Health%2C%20and%20Economic%20Impacts,leading%20to%20high%20economic%20costs. 

Valleau, J. S. and R. (2018, February 2). Road salt is bad for the environment, so why do we keep using it?. Queen’s Alumni Review. https://www.queensu.ca/alumnireview/articles/2018-02-28/road-salt-is-bad-for-the-environment-so-why-do-we-keep-using-it 

Winter Salt Management. Sustainable Technologies Evaluation Program (STEP). (2022, April 12). https://sustainabletechnologies.ca/home/urban-runoff-green-infrastructure/pollution-prevention/road-salt-management/#:~:text=The%20economic%20impacts%20of%20winter,linings%2C%20frames%2C%20and%20bumpers.