Cold weather has arrived in southern Ontario, and though there hasn’t been too much snow or freezing rain yet, that other indication of lower temperatures has arrived: salt. Sidewalks are already being covered with salt and it’s only going to get worse seeing how much people seem to use these days.
And it’s understandable. Salt does an amazing job melting ice and preventing falling snow from accumulating.
Unfortunately, salt has some real negative effects on the environment that are all too often ignored for the sake of how well it works.
Salt’s impact on the environment
5-million tonnes of road salt is used to de-ice roadways in Canada each year. Even more is used when you factor in sidewalks and driveways. All of that salt doesn’t disappear with the snow and ice it melts. Instead, it dissolves into sodium and chloride ions and washes away, down sewer drains and into the lake, or even seeps into groundwater supplies.
This isn’t a good thing. Just look at the damage salt can cause your cars or your boots—the environment isn’t immune to these effects.
It’s the chloride ions that’s the real problem. Health Canada estimates that “5% of aquatic species would be affected (median lethal concentration) at chloride concentrations of about 210 mg/L, and 10% of species would be affected at chloride concentrations of about 240 mg/L.”
For perspective, Health Canada points to water samples taken from four Toronto-area creeks that had chloride concentrations from 1,390-4,310 mg/l. Levels this high greatly affects the proper distribution of oxygen and nutrients: bottom layers of water sees less oxygen, for example.
Salt also has a major impact on soils. Plant species that thrive on soils with higher sodium—like cattails—can invade areas and effectively push out more salt-sensitive species. Often you will see a decrease in plant life in general, which in turn lessens shelter and food for wildlife.
Finally, too much salt ingested by wildlife can be deadly. This is especially true for migratory birds, where salt can be even poisonous in some cases.
What you can do
Be mindful of the salt you may use at your own home to de-ice your driveway/sidewalk. If you can avoid it altogether, great. If you must use it, here are some tips:
Shovel first. Shovel all the snow you can. You may find you won’t need that much salt at all.
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.
Uncovered salt piles
Another major source of salt leaking into the environment is improper storage. Proper salt storage demands:
Piles be covered up.
Wash water collection and treatment.
Without following these steps, salt leaking into the environment is all but ensured, especially if the first step is ignored.
Take Picton Bay, for example. Large salt piles are currently being stored by Picton Terminals on the side of a cliff overseeing the bay. Uncovered salt piles and inadequate drainage has resulted in salt leaking out into the environment.
The Save Picton Bay Facebook Group has been all over this, having contacted the MOECC and other authorities to get this matter looked into. After a long investigation, a provincial officer’s order was issued to ensure the salt pile gets covered up.
A full timeline of the investigation—including details on sampling and reporting—can be seen here.
If you notice any salt piles and are concerned about leaking, report it to us! We'll help you find answers and point you in the right direction.