Road Salt – A Safety Measure That’s Undermining Our Well Being
By Marek Krasuski
EEveryone has come to rely on salt to keep our roads safe by minimizing ice and snow build-up. Without it driving would become chaotic and accidents a normal occurrence. But is our need for safety actually jeopardizing our long term health? A recent study suggests our short term gain is causing long term pain from the damage road salt is inflicting on our environment. Freshwater scientist John Olson has found that our land use practices – including the copious amounts of salt we throw on our roads and highways – is increasing salinity (salt) levels in rivers and streams and threatening fresh water resources, biodiversity and ecosystems. The study focused on the United States, but Olson assures that Canada is similarly subject to the corrosive effects of excessive salt deposits.
The Study cites multiple reasons for the threats to our fresh water. And those reasons, collectively, are responsible for the one third of our fresh water streams and rivers that now contain 50 percent higher salinity levels. Research that went into the Study also found that 6 percent of streams and rivers in the United States are no longer suitable sources for irrigation due to high saline concentrations. Olson reveals a startling prediction: that by the year 2100, 80-plus years from now, 42 percent of low salt habitats in the US will be gone. Urbanization, waste water treatment plants, fertilizer use in agriculture and resource extraction – coal, oil and gas – all play their part in increased salinity.
To be sure, road salt is a significant contributor. Environment and Climate Change Canada claims that the carpets of salt we spray on our roadways range from two million to five million tonnes annually and this doesn’t include the salt we put on our driveways and sidewalks. When out of sight, after salt is cleared from roads in Springtime, it is out of mind, but not out of our ecosystem. It leaches into lakes, streams, rivers and backyards even in the summer. When the soil thaws salt deposits sink into the ground only to be washed into water systems once the rains begin. The effects are widespread. Olson says agriculture will suffer since salt-infused soil and the water used for irrigation will impact crops through diminishing yields .
Fish, too, are disappearing from water habitats where they once thrived, and frogs and other water borne creatures are having trouble breeding. At the risk of making alarmist claims, consider this: the Canadian Water Quality guideline for chloride in freshwater is 120 mg/L. Freshwater measurements from water sources in the GTA are pegged as high as 18,000 to 20,000 mg/L. Seawater, by contrast, has about 19,250 mg/L – virtually the same as some freshwater beds around Toronto.
Governments have looked at alternatives to road salt. Beet brine and sand are used to some degree in various parts of the continent, but road salt is by comparison cheaper, so the tendency is to stick with the most cost effective solution – though even this is debatable. Many argue that the corrosive effects of salt to roads, buildings and bridges is an enormous expense over the long term.
To stem the tide of damage to our freshwater systems requires action. Notes John Olson, “The predictions of increasing salinization of streams and rivers highlight the need for effective management and regulation to ensure we protect water resources and freshwater ecosystems,” he advised.
From a multi-sectoral perspective salinization can be reduced by restricting irrigation, controlling the amount of water used for extraction of natural resources, and limiting the amount of excavation that leaves hills and mountains exposed to rainwater that flushes salt deposits down into rivers and streams.
For its part the transportation sector can use much less salt on roadways without compromising safety. Experts agree that an entire road surface does not have to be covered for salt to be effective. Private citizens can also reduce their salt use by shoveling early and more often, thereby reducing the need to carpet driveways with salt to melt ice and snow. This could be supported by law enforcement officers to ensure their citizens are not over salting.
Salt may never be eliminated; its benefits are too valuable. But until similar, cost effective replacements can be found, we can moderate its use. Similarly, salt will never be fully extracted from the amounts we have already deposited in our freshwater lakes and streams, but what we can do is dilute it through careful judicious use in the future and proper management.☚