Spring melt becomes a salty soup

With the record-breaking amounts of snowfall Toronto has seen this winter, it’s no surprise that the city’s used higher than normal amount of salt on the city’s roads and sidewalks.

Now, with spring fast approaching and temperatures on the rise, the abundance of salty snow will be making its way in to local waterways.

The city has used 160 thousand tonnes of salt on the roads and sidewalks this winter. The usage of salt is up from previous years according to Peter Noehammer, director of transportation services for the City of Toronto.

In 2001, Toronto implemented a Salt Management Plan with the objective to “minimize salt impacts to the environment.”

Noehammer says the city continues to explore innovative technologies and alternative de-icing agents. “We’re more sensitive to the effects on vegetation, soils and surface water runoff,” he said.

Heather Marshall, a campaigner for the Toronto Environmental Alliance, said that they would like to see the city re-evaluate their salt management plans, implement more stringent guidelines and reduce salt usage to 50 per cent.

“It’s a huge environmental issue,” Marshall said. “It’s over used … it’s a toxic thing that we don’t need to have.”

In a 2006 report called “A Low-Salt Diet for Ontario’s Roads and Rivers”, released by Riversides Stewardship Alliance and Sierra Legal Defence Fund, shows that the City of Toronto is the largest municipal user of road salts in Canada.

The study indicated the peak chloride concentration for urban fresh water streams in the winter is over 1,000 milligrams per litre. Chloride concentration for highway runoff is over 18,000 milligrams per litre.

“What we’ve seen for Toronto is that it’s actually more like 4,000 (per litre) and in some cases we’ve actually had quotes in Toronto that it’s as high as 11,000, Marshall said. “That’s approaching the salinity of sea water.”

The peak chloride concentration for ocean water is 25,000-30,000 milligrams per litre.

Julie Schroeder, a toxicologist for Ontario Ministry of the Environment said “The concentration of road salt for a small invertebrate species in fresh water is about 1.4 grams per litre, about a gram or above for a short term level that would be likely to cause mortality to 50 per cent of the organisms exposed to it.

“It can cause long-term effects at lower levels,” Schroeder said. “Essentially it’s improper storage.

“Environment Canada is going to be reviewing the effectiveness of those codes of practice to reduce road salt use and to mitigate environmental impacts,” Schroeder said.

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Posted: Mar 17 2008 8:40 pm
Filed under: News