City streets peppered with salt

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This article was published 10/02/2006 (7375 days ago), so information in it may no longer be current.

THE mild winter has turned Winnipeg’s regional roads into the asphalt equivalent of margarita glasses, as city crews use more salt to clear streets instead of sending slower, costlier snowplows into action.

This January, the City of Winnipeg spread more than 2.5 times the amount of salt on major streets as it did during the same period in 2005, which amounts to cost savings at Public Works but potentially more vehicle corrosion and slight environmental damage across the city.

“The benefit of salt is it gives you much safer roads, more quickly. And it’s cheaper,” said Public Works spokesman Bob McDonald, noting road-salting costs half as much as the plowing/sanding combo and requires half the time. “There are certainly some negatives, but the benefits outweigh them.”

The city uses salt to melt snow instead of sending snowplows and sand-spreaders on to major arteries whenever the temperature rises above -10 C.

This January, the average temperature was -7.5 C, about 10 degrees warmer than normal.

Overall, the mild winter will see the city use almost twice as much salt as it would during an average year, McDonald said.

The city expects to use 23,700 tonnes of road salt this year versus 13,000 in an average year.

But that’s still within the normal range of variation, as the city sprinkled almost 30,000 tonnes of salt on major streets during the winter of 1995-96.

“This goes in cycles, which are directly related to weather,” McDonald said.

Most of the salt applied to city roads is sodium chloride, which is ordinary table salt. A small amount of calcium chloride is used as a wetting agent, McDonald said.

As well, about five per cent of the sand spread during colder weather is comprised of salt, which acts as an anti-clumping agent.

All this extra sodium may corrode vehicles as well as metal structures such as street signs and bridge supports. But it will have no direct effect on actual streets, other than creating more meltwater, which contributes to pothole-creation when it freezes overnight, McDonald added.

While the autobody industry may stand to benefit, this year’s additional sprinkling of salt will likely have no effect on Winnipeg vehicles in the short term, said Tony Isbister, body shop manager for Winnipeg Dodge Jeep.

But years of warmer weather and more road salt will take a toll, he said.

Isbister said it’s extremely important to wash your car as often as possible to remove salty crud from the undercarriage and fenders — and park outside, whenever possible.

“Parking in a heated garage is the worst thing you can do in the winter, because salt is only active in warmer temperatures,” said Isbister, adding corrosion barely happens at all below -20 C.

“I tell all my customers, leave it outside unless they want to wash their car every day.”

Manitoba Public Insurance, meanwhile, isn’t concerned with the use of more salt because the insurer does not handle sodium-damage claims.

“Our position is we don’t tell the city how to clean the roads,” said MPI spokesman Brian Smiley. “The city has to do whatever it has to do to keep roads safe.”

While more salt is obviously not great for the freshwater environment, it’s unlikely this year’s additional sprinkling will have a noticeable effect on plants and animals around Winnipeg, said Mark Hanson, a University of Manitoba ecotoxicologist.

The effects of road salt on aquatic animals are brief, because it tends to stay on roads all winter and then get flushed into streams and rivers all of a sudden during the spring snowmelt, said Hanson, an assistant professor in the Department of Environment and Geography.

He said it’s impossible to predict the specific effects of road salt on Winnipeg’s environment without studying exactly how much is used over how wide an area.

A 2001 Environment Canada study concluded that the five million tonnes of road salt used across the country each winter contaminates groundwater and surface water and poisons both plants and animals, especially alongside roads.

The greatest harm was found around urban areas in Ontario, Quebec and the Maritimes, which experience milder winters than Manitoba and use more salt.

During the winter of 1997-98, 1.8 million tonnes of road salt was spread across Ontario, 1.5 million tonnes across Quebec and 374,000 tonnes across Nova Scotia — compared to only 70,000 tonnes in Manitoba, Environment Canada found.

A 2004 University of Michigan study of 43 wetlands in the northern U.S. state found road salt did not harm significant numbers of invertebrates such as mayflies, snails and midges.

bartley.kives@freepress.mb.ca

PHOTO WAYNE GLOWACKI/WINNIPEG FREE PRESS

Salt of the earth

Everything you wanted to know about sodium chloride, on Winnipeg roads and elsewhere

Salt sprinkled on Winnipeg roads, January 2005: 2,460 tonnes

Salt sprinkled on Winnipeg roads, January 2006: 6,067 tonnes

Why the increase? Salt is only effective when the temperature is above -10 C. The average temperature this January was way above normal at -7.5 C.

Salt sprinkled on french fries and other orders by patrons of C. Kelekis Restaurant, during an average week: Up to eight kilograms, a decrease from earlier decades.

Why the decrease? “A lot of customers just don’t use as much salt anymore,” says proprietor Mary Kelekis.

Money spent on road salt by city hall in January 2005: $249,000

Money spent on road salt by city hall in January 2006: $869,000

Price of a 445-gram jar of fleur de sel, a gourmet salt collected by hand on the French seashore: $10.89 at Stephen & Andrews

Cost savings of spreading road salt on city roads versus snow plowing and spreading sand: About 50 per cent

Average cost of replacing a corroded car door: $1,000 for the door itself, plus painting and installation.

Parts of your car most vulnerable to salt corrosion: The undercarriage and fenders.

Best way to protect your car from salt corrosion: Wash it often, preferably by hand or with a wand. Touchless car washes are also OK.

Best place to leave your car in the winter to avoid salt damage: Outdoors, where cold temperatures inhibit the chemical reactions that cause corrosion.

Saltiest place in Manitoba: Lake Winnipegosis Salt Flats Ecological Preserve, about 130 kilometres north of Swan River on Highway 10.

Salt composition of unpolluted freshwater lakes and rivers: Less than 0.5 per cent

Salt composition of human blood: 0.9 per cent

Saltiest place on Earth: The Dead Sea, which borders Jordan, Israel and the West Bank.

Composition of a “Salty Dog”: Grapefruit juice, gin and salt.

Salt composition of the world’s oceans: 3.5 per cent.

— Compiled by Bartley Kives