[All] road salt polluting streams

[Norah & Richard]

MARTIN MITTELSTAEDT

 From Friday's Globe and Mail Published on Friday, Mar. 05, 2010 12:00AM 
EST Last updated on Friday, Mar. 05, 2010 5:37AM EST

ENVIRONMENT REPORTER

One of the most detailed investigations ever conducted in Canada into 
the fate of road salt has found that it is polluting groundwater and 
causing some streams during winter thaws to have salinity levels just 
under those found in the ocean.

The elevated salt readings were detected in Pickering, where researchers 
from the University of Toronto have been studying how the salt spread on 
highways, such as the 401, and other roadways through suburban sprawl 
affects water quality. They 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.

"Our findings are pretty dramatic, and the effects are felt year-round," 
said Nick Eyles, a geology professor at the university and the lead 
researcher on the project. "We now know that 3,600 tonnes of road salt 
end up in that small lagoon every winter from direct runoff in creeks 
and effectively poison it for the rest of the year."

He called the findings, which were published recently in the journal 
Sedimentary Geology/,/ "a really bad-news story" involving a "relentless 
chemical assault on a watershed."

The Pickering area provided researchers with an ideal place to study the 
effects of road-salt spreading, because most of the city lies within a 
relatively compact 27-square-kilometre watershed, where it was easy for 
pollution monitors to track where salt spread on roads ended up.

About 7,600 tonnes of salt is applied each year to roads in the 
community. About half of this amount seeps into groundwater, which in 
turn flows into streams year-round, making the water courses more salty 
than they should be, according to the research. The rest drains into 
Frenchman's Bay, which is visible to commuters on the 401 and has a 
struggling fish population because salt levels are more than double the 
amounts typically found in the Great Lakes.

The salt water "knocks out fish," Dr. Eyles said, adding that in the 
most contaminated areas, only older fish can survive, while younger ones 
move to areas of the lagoon closer to Lake Ontario and its fresher water.

The finding of major impacts on Pickering's ground and surface water 
suggests a far greater toll from the use of salt elsewhere across 
Canada, where an estimated five million tonnes, or approximately 150 
kilograms per Canadian, is used on roads each year to make them safe for 
travel in winter. The vast majority is applied in Ontario and Quebec.

"It's a general problem. ... There are lots of other areas like this," 
Dr. Eyles said, referring to the Pickering findings.

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.

"It's a toxic material and yet we continue to throw it with gay abandon 
on our roads," he said.

The University of Toronto research was based on water monitoring between 
May, 2002, and March, 2003, before the code went into effect.

It noted that after winter thaws, there were spikes in the amount of 
salt in streams, with those taking runoff from the 401 having 
approximately double the concentration of the pollutant than 
watercourses nearby that don't take its storm water. Runoff from the 
highway, Canada's busiest, also contains benzene, toluene, and xylene, 
hydrocarbons associated with contamination from underground gasoline 
storage tanks.

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.



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