Crews decontaminate Seine

Enlarge Image

This patch of the Seine behind 421 Archibald St. is undergoing what’s being called one of the most complex environmental cleanup jobs in the city’s history, with the site contaminated in the early 20th century. (MIKE.DEAL@FREEPRESS.MB.CA)

WINNIPEG – Environmental crews are diverting a stretch of the Seine River and removing six football fields' worth of petrochemical-laced St. Boniface soil as part of a multimillion-dollar effort to clean up contamination that dates back a century.

In what's being described as one of the most complex environmental cleanup jobs Winnipeg has ever seen, Manitoba Conservation is supervising the remediation of a 9.1-acre portion of the Seine River and an eastern bank that have been contaminated with coal tar since the early 20th century.

The land in question, at 421 Archibald St., was the site of a roofing plant that began operating in 1909. The land was contaminated over decades and changed hands several times before environmental inspectors learned of the problem in 1994.

For the next 15 years, the province worked out a plan to clean up the riverbank and river bottom, dealing with both former owners and current owner Winniman Land Company Ltd.

A cleanup order was finally issued this June under the Contaminated Sites Remediation Act, said Randy Webber, Winnipeg supervisor for Manitoba Conservation.

"It took a number of years to simply get a handle on the nature and extent of the impact. Then it took a couple of years to develop a remediation plan to address all the contamination issues," Webber said. "On these big, complex sites, 10 years is not an unusual period of time to find out about it, investigate it and figure out how to address it."

The cleanup plan essentially involves removing 48,000 tonnes of contaminated soil and clay and replacing it with clean fill. The problem is that both a river and a riparian zone -- a stretch of vegetation vital to fish and wildlife -- run right through the contaminated site.

"This is the most complicated project I've ever worked on," Webber said.

This week, crews financed by Winniman and Honeywell International -- the owner of a company that once owned the site -- started the four-month task of removing and replacing the soil and clay.

The most heavily contaminated soil will be shipped to a hazardous-waste landfill in Sarnia, Ont., while less contaminated fill will be trucked to a Manitoba landfill, said Lindsay Shepherd, project engineer for remediation firm Conestoga Rovers & Associates.

Crews have also dug a new channel to carry the Seine for about 100 metres while its existing channel is excavated and replaced. The river will be returned to its original course once the remediation work is finished, Shepherd said.

The remediation plans also call for new vegetation to be planted on both banks of the river next spring to replace the riparian zone that's been sacrificed for the sake of the cleanup, Shepherd said.

"It will be prettier to walk alongside it."

For decades, the coal tar on the east bank of the Seine could be seen seeping out of the banks. Earlier this decade, Manitoba Conservation placed a boom across the river to prevent oil slicks from flowing downstream from the site into the Red River.

David Watson, president of volunteer group Save Our Seine, said his organization is relieved the remediation work is finally taking place.

"There are definitely mixed feelings about all the trees and shrubs being removed, but in the long term it has to be done," he said.

Project manager Shepherd declined to disclose the precise cost of the remediation job, other than to say it is in the millions.

The work also required approvals from the City of Winnipeg and Fisheries and Oceans Canada.

The Seine remediation site is closed to paddlers while work is underway, but a portage trail on the west bank of the river allows canoeists to bypass the site.

bartley.kives@freepress.mb.ca

The coal tar must go

Cleaning up a century of contamination:

1909: A roofing company begins operating on the east bank of the Seine River, just south of the CNR Sprague train bridge. The plant originally uses coal tar. In later decades, asphalt replaces coal tar at the Old St. Boniface site.

1994: After the land changes hands several times, Manitoba environmental inspectors learn of soil contamination and try to figure out who is responsible for the remediation. Eventually, inspectors learn the riverbanks and river-bottom clay contain petrochemicals.

2009: After approving a remediation plan, Manitoba Conservation finally issues a cleanup order under the Contaminated Sites Remediation Act. Current site owner Winniman Land Co. plans to remove and replace 48,000 tonnes of soil by the end of the year.

2010: The vegetation alongside the cleaned-up riverbank will be restored.

Republished from the Winnipeg Free Press print edition August 26, 2009 B1