Environmental Science & Engineering - September 2001

Road salt pickling Toronto rivers

Please don't drink the run-off.
Photo - Steve Davey

Tests found salt levels 140 times Ontario limits in Toronto's rivers, according to a study carried out last winter. On March 27, Kevin Mercer, of Riversides Stewardship Alliance, released the results of river salt testing which the city conducted in December and January. In one case, samples of storm sewer discharge taken at a tributary of Mimico Creek, near Hwys 427 and 401, contained a salt concentration of 35,000 milligrams per litre ­ 140 times the limit set by provincial water-quality standards.

"You might as well be pickling whatever lives or would like to live in that water," said Mercer. "You couldn't drink it. Provincial water-quality standards set 250 milligrams per litre as the limit for salt." He called for city council to significantly reduce the 130,000 tonnes of salt Toronto crews put on roads each winter. He also wants the city to look at alternatives to road salt.

Environmentalists have requested Toronto's works committee to endorse an Environment Canada report which classifies road salt as environmentally toxic.

A five year assessment by Environment Canada found that the five million tons of road salts used across the country every winter contaminate groundwater, surface water, poison wildlife and harm vegetation.

Streams, small lake ecosystems and groundwater are particularly vulnerable to road salt, which should be added to the Canadian Environmental Protection Act's toxic substances list, Environment Canada said in its report.

Road salts are sodium chloride, calcium chloride, potassium chloride, magnesium chloride and ferrocyanide salts. The principal salt used on roads is the table salt used on food. The only irritation for humans from road salt is its adverse effect on the taste of contaminated roadside well waters, said the study.

This article was abridged from Environmental Science & Engineering magazine, which also contains many more articles not posted on our Web Site. See our home page on how to order your subscription. We regret we can only accept orders from Canada and the United States.