The price of salt: How road salts are affecting our Great Lakes
Around Lake Ontario, winter-weather forecasts bring out road salt. This means crunchy sidewalks, dog booties and salt-stained shoes. It also means severe impacts for Lake Ontario’s watershed and its aquatic life. When rain or snowmelt wash road salt (sodium chloride; Na-Cl) into storm sewers and water ways it causes a damaging spike in salinity.
The image was taken by markgranitz. It illustrates the typical overuse of road salt on the sidewalks.
Impact on Aquatic Life
In Ontario, we use road salt to de-ice sidewalks, roads and parking lots, and to improve safety during winter temperatures. However, it’s used in excess more often than not and is turning freshwater into saltwater. The salty waters can get into groundwater supplies, kill sensitive species, and ultimately degrades ecosystems. Spots in Ontario have become so salty that there have been sightings of saltwater animals in the freshwater creeks. Reports of saltwater blue crabs living in Mimico Creek is just one troubling case that illustrates the extent of sodium chloride pollution in watersheds of Lake Ontario.
A Blue Crab spotted on the shores of Lake Ontario. Photo by Emma Lagunday
As the salt makes the freshwater livable for saltwater species, freshwater species are increasingly at risk from spikes in sodium chloride levels in winter months. Research shows the salinization of freshwater causes increased parasitism on the North Leopard Frog, a native amphibian to Ontario. In salmon species, sodium chloride stops growth at the most important life stage, which corresponds with drops in salmon population sizes.
This is the Northern Leopard Frog native to the Great Lakes are and Southern Ontario. The photo was taken by ~Sage~
In the worst cases, research shows salinization of freshwater leads to mortality in small aquatic species like freshwater shrimp, mussels, and insects. Freshwater ecosystems rely on these animals because they feed the larger animals like fish and birds. When populations of small aquatic animals drop as sodium chloride levels increase, the population of larger aquatic animals also drops. This causes major changes to the food web and damages the overall aquatic ecosystem. All-around road salts cause permanent changes to the aquatic ecosystem, including tremendous losses in biodiversity.
How much road salt is enough?
In Ontario, the solution right now is to use less road salt on driveways, sidewalks, and paved parking lots. The over-application of road salt is common and unnecessary. The illustrations below show the average rate at which the Ministry of Transport applies to roads (top left) and the over-application typically seen in parking lots (bottom right).
These were produced by Sustainable Technologies Evaluation Program (STEP), working on Road Salt Management in Ontario as it relates to our water resources.
Most of the public is simply unaware of the impacts that road salts have on the local environment. Plus road salts are really cheap and there is a general lack of application protocol and enforcement. These factors often leave us prone to excessive application during the freezing winter months.
Every winter the topic of roads salts appears on a variety of blogs and media outlets. Extensive research and work is occurring across Ontario by local conservation authorities on salt management including Lake Simcoe Region Conservation Authority. Research also continues to look for alternatives to road salts, including beet brine which is currently being used in Calgary. However, if you are interested in using alternatives, make sure to research what exactly is contained in the product, as many contain chloride in other forms.
Actions you can take
If you can avoid using salt altogether, great! If you must use road salts, here are some easy tips to reduce your use and protect our lakes:
Photo by Stephen Depolo.
Shovel first. Shovel all the snow you can. You may find you won’t need that much salt at all.
Be mindful of the amount of salt you use: 20 grams is approximately one handful of salt.
Use salt on ice only.
Avoid applying salt near plants as you could heavily damage them.
Be mindful of the salt that collects on your car. Washing your car can lead to salt flowing off into a storm drain. Limit the frequency you wash your car in winter and “Skip The Wash, Save The Lake”.
Skip The Wash, Save The Lake
Salt harms Lake Ontario every winter. In response, Toronto Honda and Toronto Kia launched a campaign in collaboration with Lake Ontario Waterkeeper. Skip the Wash, Save the Lake, reduces water pollution and the number of car washes at both dealerships. Toronto Honda and Toronto Kia donate to Lake Ontario Waterkeeper for every wash skipped. Donate now and you too can support the cause!
Image by Lake Ontario Waterkeeper