No one likes slipping and falling on ice & we want to know that our roads and sidewalks are maintained effectively, so as to not result in an unnecessary accident. However, Green Venture believes that this desire for safety does not have to compromise our desire for a healthy environment, and more specifically, a healthy watershed! Did you know that the average City in Ontario uses approximately 100,000 tonnes of road salt every winter (Summers & Valleau, 2018)?
What are the risks?
Road salt contamination happens when snow melts and all the salt put down over the course of the winter is washed out by the melting snow runoff. This runoff can go three places:
- Storm Sewers: The salty water can be washed into the storm drain which, depending on if your sewage system is combined or separated will impact the environment in different ways. If your storm water is separated all road salt (and other contaminants) will be washed into waterways with minimal filtration. If your stormwater is combined with sewage it will go to a treatment plant. However, combined sewage systems are prone to overflow during storms or in the case of road salt, melting events. We hear about issues in sewer management resulting in high levels of e coli in our rivers and streams but rarely do we hear about the impact that adding salt water to these ecosystems have. In reality adding this much salt to an ecosystem is “toxic to aquatic life, and even low concentrations can produce harmful effects in freshwater ecosystems” (Hinsdale, 2019).
- Road Runoff: Road salt also runs off directly into local waterways, mixing with additional contaminants and damaging these aquatic ecosystems.
- Groundwater: Road salt can even contaminate the groundwater which can be damaging to human health where people’s main source of drinking water is from groundwater. The salinity levels are so high in some areas that people with high cholesterol are advised not to drink from their wells as taking in that much extra sodium would pose an increased health risk to them.
In 2014 the City of Hamilton made a 40 Million dollar deal to secure road salt at increased usage for the next 5 years (Dongen, 2018). This excessive usage has significant environmental implications for surrounding ecosystems, specifically water quality, but road salt is also extremely damaging to plants and animals. We think it’s important that the City of Hamilton begin to seriously consider alternatives. In the meantime you can apply these alternatives on your own sidewalks and driveways to ensure you’re doing your part to reduce degradation of Hamilton’s watershed.
What are the alternatives?
Currently, road salt is viewed as by far the cheapest way to reduce ice accumulation on our roads and walkways. However, this changes when you consider all the damage road salt causes not only to the environment, but also to our infrastructure. Salt corrodes our roadways, shoes, tires, & dogs feet, but most importantly our overpass highways. Road salt has long been used excessively, especially in areas of high concern regarding skidding out, such as; on an overpass highway. Unfortunately this has proved to be very dangerous, applying excessive amounts of corrosive road salt to these overpasses has caused severe damage. For example, one of the most prominent reasons the Gardiner Expressway in Toronto is falling apart slowly, is due to excessive road salt usage. The damages caused by road salts are costly and risky, here are some alternatives that although may cost more up front, may be worth it in the long run. The options below are also very useful for personal use around your home to reduce your individual impact on the surrounding ecosystem. If you currently use road salt on your driveway/walkways please consider switching to one of the following more sustainable options;
Sand is not used in the same way that road salt is, as sand does not have the ability to melt ice. Instead, sand is applied to increase traction on ice. You need about 3 times as much sand as you do salt in order for it to be effective, this makes sand fairly inapplicable for a municipality like Hamilton. The cost and effort it would take to distribute enough sand for the roads would be too resource intensive. However, sand can be a useful alternative for a small area such as a driveway. It is important to note that although sand is equally effective in any temperature sometimes it is unable to do enough to increase traction in extremely icy areas. If you chose to use sand as an alternative to salt ensure you are still walking carefully as slippage may still be a risk. Lastly, it is important to note that while sand does not increase the salinity of our watershed it still has fairly significant environmental effects. Sand can damage stormwater infrastructure by clogging it up, additionally sandy runoff will reduce water quality, increasing it’s turbidity and reducing the amount of sunlight the ecosystem would regularly receive. One way you can reduce the impact of your driveway is by making sure you sweep up the sand left on your driveway once the snow and ice have melted.
Beet Juice is a far less corrosive alternative to road salts, it actually has anti corrosive properties, making it a much safer alternative from the perspective of damage to our bridges and cars. However, although this alternative is plant based, inputting large quantities of beet juice into the environment is not without its environmental disadvantages. A study on the effects of Beet juice on mayflies reveals that the beet juice caused excessive water retention in mayflies & that overtime it can lead to altered organ function (American Physiological Society, 2018). Beet juice works in temperatures up to -21 degrees celsius could be an alternative applicable to homeowners with extremely slippery driveways. Municipalities should consider replacing road salt with a beet juice blend on areas affected negatively by the corrosion of road salts.
The salty brines that things like mozzarella cheese and pickles float in, are surprisingly good at stopping ice accumulation. These mixtures also work in colder temperatures than road salt which stops being effective at approximately negative 15 degrees celsius. These brines last up to approximately negative 21 degrees. Additionally another bonus of these brines is that they stop what ice does accumulate from binding to the pavement, making ice removal much easier. This is a huge bonus for anyone who doesn’t enjoy scraping compacted snow and ice off their driveway! As for environmental effects these mixtures still add chloride to the surrounding ecosystem, but at least it is 14-29% less than what comes from our road salt use.
Green infrastructure does not combat slippery roads in the typical way road salt or any of the other alternatives listed above do. Instead, green infrastructure gives the surrounding landscape better drainage, reducing the formation of ice because there is less water sitting on our roads, driveways and walkways. Unfortunately, green infrastructure is unable to filter out the chloride in road salts because it binds to the water unlike other contaminants. However, with more implementation of green infrastructure in our cities, we will not need to use nearly as much of the road salt or their greener alternatives in order to maintain safe ice management practices. A combination of green infrastructure and ideally a chloride free, non corrosive ice remover would be the most
eco friendly and likely the most cost effective option to keep our winter roads safe.
As a final take home message, I would like to remind everyone that the effects of too much road salt is extremely harmful to our watershed. There is a misconception around how much road salt we need to put down in order to keep our spaces ice free (Smart About Salt Council, nd.);
If you must use salt, ensure you are using it responsibly and be sure to sweep up any leftovers!
American Physiological Society. (2018, October 29). Plant-based ‘road salt’ good for highways but not for insects: Study finds beet juice deicer causes fluid retention and alters organ function in mayflies. ScienceDaily. Retrieved January 30, 2020 from www.sciencedaily.com/releases/2018/10/181029135232.htm
Dongen, M. V. (2018, October 26). Salt shortage no threat to Hamilton roads. Retrieved January 29, 2020, from https://www.thespec.com/news-story/8989374-salt-shortage-no-threat-to-hamilton-roads/
Foung, C., Blakelock, C., & Green Communities Canada. (2015, December 16). Green Infrastructure in Winter. Retrieved January 30, 2020, from http://www.raincommunitysolutions.ca/en/green-infrastructure-in-winter/
Hinsdale, J. (2019, July 31). How Road Salt Harms the Environment. Retrieved January 30, 2020, from https://blogs.ei.columbia.edu/2018/12/11/road-salt-harms-environment/
Silverman, R. (2014, February 6). Why Pickle Brine Is a Secret Weapon Against Ice. Retrieved January 30, 2020, from https://www.nationalgeographic.com/news/2014/2/140204-melt-snow-ice-salt-beet -juice-pickle-brine/
Smart About Salt Council. (n.d.). Salting Shift Campaign. Retrieved February 3, 2020, from http://www.smartaboutsalt.com/Salting-Shift-Campaign/
Summers, J., & Valleau, R. (2018). Road salt is bad for the environment, so why do we keep using it? Retrieved January 29, 2020, from https://www.queensu.ca/gazette/alumnireview/stories/road-salt-bad-environment-so -why-do-we-keep-using-it.