A new study, one of the most detailed in Canadian history, has concluded that road salt is polluting our lakes and during the spring thaw actually creating salinity levels that approach those of the ocean!
The study, conducted near Pickering, found that so much salty water from the community is ending up in Frenchman’s Bay, a scenic lagoon on the shores of Lake Ontario, that the small water body is being poisoned.
Environment Canada has recognized that salt has adverse impacts on wildlife, plants, water and soil, and in 2001 considered adding it to the country’s list of the most toxic substances. Instead, in 2004, the government instituted a voluntary code of practices to encourage municipalities and others to use the de-icer more sparingly, while maintaining highway safety. But with the vast amount used, huge quantities are still polluting soil and water, according to Dr. Eyles, lead researcher on the project.
Stormwater, The Journal for Water Quality Professionals, reports that the effects of road salt are not limited to salination of adjacent streams and lakes. Of the 15 principal tree genera occurring in Canadian forests, 11 have been rated as sensitive to road salt. In Jasper National Park, AB, road-salt ingestion is responsible for kills of elk and bighorn sheep. In northern Ontario and Quebec, ingestion of salty snowmelt is a major cause of moose/vehicle accidents. Stormwater cites 12 reports of bird kills associated with road salt in the US, Canada, and Germany. Two reports involved kills in excess of 1,000 birds. Seed-eating birds may not be able to distinguish between road-salt crystals and the mineral grit their diets require.
But is sodium chloride the only solution to slippery roads in the winter? Two alternatives exist, both far more environmentally friendly than common salt. Calcium magnesium acetate (CMA) is relatively harmless to plants and animals, noncorrosive to metals, and nondestructive to concrete and other highway materials. Potassium acetate (KA) – often used as a base for commercial chloride-free liquid deicer formulations – is low corrosion, relatively high performance, and low environmental impact. So why aren’t we using these products?
The bottom line is the bottom line. In Ontario we have a relatively inexpensive local supply of salt. Ontario budgets $160 million per winter for road maintenance, with Toronto alone spending about $10 million annually on road salt. The cost of CMA on the other hand, due to being manufactured from a mixture of acetic acid (from corn fermentation) and dolomite, can be 20 – 30 times higher! KA costs approximately as much as CMA to produce.
So where do we go from here? Continue to use inexpensive road salt or convert to more expensive CMA or KA? Environment Canada says it is currently reviewing whether the voluntary practices code has led to any reduction in the amount of salt being spread on roads. “If it is concluded, based on the review of progress, that other steps are needed for the management of road salts, Environment Canada will consider a range of possible options,” the department said in reaction to the study.
Obviously some salty debate can be expected before we come to any long term solution.
Sources: Stormwater, Globe and Mail, The Star, Canadian Wildlife Federation
