Dennis Hanagan –
Toronto City Council wants the Ontario government to cut the amount of road salt seeping into Toronto’s rivers and streams, where it is increasingly lethal to aquatic wildlife.
Ward 11 (University-Rosedale) Councillor Dianne Saxe, an environmental lawyer who was the province’s environmental commissioner from 2015 to 2019, has called salt pollution in Toronto’s waterways “poison.” The Canadian Environmental Protection Act calls it a toxic substance.
Excessive salt in waterways can dehydrate freshwater organisms, kill larvae and eggs of fish and amphibians, and decrease zooplankton that fish feed on. Excessive salt can also cause structural damage to roads, bridges and pipes.
Saxe argues that private property owners and snow removal contractors “frequently use grossly excessive amounts of salt” to protect themselves from slip-and-fall lawsuits.
Council wants the Minister of Municipal Affairs and the Attorney General to develop best-management practices for salt use that would protect property owners, building managers, contractors and municipalities from lawsuits, provided “all reasonable steps” to clear ice and snow have been taken.
Research scientist Lyndsay Cartwright, with the Toronto and Region Conservation Authority (TRCA), told the bridge that four out of five water quality monitors on the Don River show “significant increasing trends” in road salt pollution. Road salt, also known as rock salt, contains chloride.
Cartwright said that on average the Don River samplings show 330 mg of chloride per litre of water, while guidelines to protect aquatic life set maximum chronic exposure at 120 mg/litre.
A process called phytoremediation might help relieve the chloride problem. It employs salt-tolerant plants called halophytes that extract salt from soil and store it in their leaves and tissues above ground. Common such plants in Ontario are Sand Dropseed and Switch grass.
“We think it’s an important part of the solution to the issue of salt,” said Cartwright. Halophytes would be planted near roads to catch salt runoff, hopefully before it reaches waterways. It’s being tested now at Pearson Airport; a similar test will be done at Lake Wilcox in Richmond Hill.
Cartwright said more research is also needed to remove “legacy” salt. “Not all salt is going directly from the road to the streams. It’s going from the road, getting stuck in the soil near the road … then it’s slowly released over time,” Cartwright explained.
She agrees with City Council that liability protection legislation is needed.
Vincent Sferrazza, director of Toronto’s operations and maintenance for Transportation Services, told the infrastructure and environment committee the city will work with the TRCA and Toronto Metropolitan University (formerly Ryerson) to pilot “a more direct liquid application” that uses a brine mixture rather than just rock salt to clear ice and snow. The solution is proactive anti-icing rather than reactive de-icing.
A TRCA synthesis of American studies found that anti-icing using brine requires only a third to a quarter of the amount of salt Toronto uses.
Sferrazza said his division is also looking at an artificial intelligence application for salt spreaders that collects information about road and atmospheric conditions to determine an “appropriate application rate” of salt to clear ice and snow.
Saxe said that as Ontario’s environmental commissioner she concluded that the lack of provincial legislation “is the critical problem here.” In the meantime, she added, salt in creeks, rivers and ponds is getting worse “and the ability of turtles and wildlife of all kinds to survive it is eroding.”
In a letter to the committee, Claire Malcolmson with the Ontario Salt Pollution Coalition said the coalition has advocated for decades for reduction of salt pollution in fresh waterways. This year, she said ten municipalities from southern Ontario to Sudbury have adopted motions similar to Toronto’s calling for Ontario government action.
Joe Salemi, executive director of Landscape Ontario Horticultural Trade Association, told the committee in a letter that snow and ice contractors face “sky-high” insurance costs leading to “a shrinking pool” of insurers for them. Salemi said the result is contractors are exiting the industry.
Requests to the Ministry of Municipal Affairs and to the Attorney General for comment were not answered by deadline.
