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Containing contamination

How Oshawa is monitoring one of its crucial downtown assets


Thanks to its past life as a production facility for McLaighlin Motor Company (later General Motors of Canada), parts of the land that now houses the YMCA, Oshawa courthouse and a soon-to-be apartment building are contaminated with trichloroethylene, a chemical used for cleaning grease. The parcel of land has been the site of constant clean-up, remediation and monitoring since it was first acquired by the city more than 30 years ago.

By Joel Wittnebel/The Oshawa Express

It’s no mystery, automotive manufacturing is greasy work.

And in the days when the McLaughlin Motor Company (a growing auto builder that would later change its name to General Motors) operated in Oshawa’s downtown core, the best way to get rid of that grease was trichloroethylene (TCE). The chemical compound was used heavily in the 1950s as a degreaser. Gallons of the stuff would have been used on the site that is now home to the YMCA, Oshawa’s courthouse and soon-to-be apartment buildings.

And like a ghost left behind by the demolished auto plant, TCE lingers in the soil, forcing the city to take several steps to protect current and future developments in the downtown.

The underground problem

In 1985, the city acquired the eight acre plot in a land swap with General Motors.

It appeared there was not a lot left of the old plant, which had previously been demolished, save for the concrete floor slabs, but the soil told a different story. Contamination by TCE lingered in the soil and groundwater along with traces of metals such as cadmium and lead.

Tom MceLelwain, a principal with Golder Associates, the consultants who were responsible for the land’s cleanup, said the contamination existed across the site.

“The entire city block, certainly including the eight acres, had been subjected to groundwater, soil too, but groundwater impacts particularly by chlorinated solvents, by greasing solvents that were used by General Motors since 1903,” he says.

So, when Oshawa looked to develop the large piece of under-utilized downtown, they had their work cut out for them.

The clean-up begins

The first development to take hold on the site was the YMCA in 1998, sitting at the corner of Mary and William streets.

Ironically, this first development remains one of the most contaminated sites belonging to the former auto plant.

McLelwain explains that is due in part to the fact that the YMCA site was the only location of the old plant that had a deep basement.

“So the impacts that were present, were present in the soil that was already two levels below grade,” he says.

As well, the parking lot to the east and the groundwater beneath it still suffer from heavy TCE contamination.

“If you had dirty metal, that water would probably clean it up nice,” McLelwain says of the parking lot site.

However, McLelwain says the reality is, TCE is only harmful in large, continuous doses.

“You’d have to be drinking the water…all day for 20 years before it would be an issue for you,” he says.

Less stringent regulations at the time of the YMCA’s construction allowed this contamination to remain.

“They were still pretty stringent. There is nothing in the groundwater that I’m aware of at the Y that presents a health and safety hazard,” McLelwain says. “But it still doesn’t meet today’s standards, which are ridiculously tight.”

contamination_1The parcel’s second occupant

In 2006, in an attempt to bring together several courthouses across Durham Region, the province was seeking a site for a consolidated courthouse. Oshawa had just the place.

However, the province, looking to avoid any future issues with contamination, placed strict environmental conditions on the land’s cleanup.

Golder, retained by the city, carried out that clean up as well.

Around the same time, Oshawa had interest from Atria Developments, who was looking to build on the 100 Bond St. site, so both sites underwent a thorough spring cleaning.

Soil was dug out nearly to bed rock on both sites and several monitoring wells were installed in order to continuously monitor the state of the groundwater. The remaining groundwater not removed with the soil was treated chemically, McLelwain says.

“By injecting chemicals into the ground…those chemicals sort of magically make the TCE disappear. It sounds silly, but they literally do disappear,” he says.

The injected fluids simply work to break down the chemical parts of TCE into its basic components, none of which are of an environmental concern.

As well, surrounding the courthouse is a Fort Knox style system of underground barriers around the north, west and south sides that prevent any contamination from getting in, as well as any contamination from getting out.

As part of the deal with the province, following their approval of the city’s clean up efforts in 2007, allowing construction on the courthouse to begin, Oshawa must continue to monitor any contamination on the site.

A monitoring system is installed in the basement of the 450,000 square-foot courthouse and reports are prepared annually by the city on the status.

A Freedom of Information request filed by The Oshawa Express for copies of these reports from 2013 to 2015 came back with a $590 price tag.

According to Paul Ralph, the city’s commissioner of development services, he is not aware of any recent issues.

“To date, since I’ve been commissioner, there haven’t been (any),” he says.

Ralph was appointed commissioner last year.

Mindful monitoring

The barriers surrounding the courthouse are not the only efforts in place to keep TCE from free-flowing around the eight-acre site.

While all contaminated soil is said to have been lifted and carted away, the threat of groundwater seepage from the YMCA property still poses a threat to the development at 100 Bond, as groundwater flows naturally from north to south.

“So it flows from beneath where the YMCA is towards the Atria development,” McLelwain says. “If it was allowed to continually flow south without being intercepted or intervened, it could recontaminate 100 Bond.”

To prevent this, the city uses a system that was put in place during the construction of the YMCA and as part of the obligations to the province when the courthouse was built. An underground gravel trench collects water from a deep foundation drainage system beneath the YMCA. This water is then pumped through a treatment system, housed in a small shed on the YMCA property. It is then pumped out into the city’s storm water system.

“That gravel trench can then continually collect that contaminated groundwater from beneath the parking lot and also, to a certain extent, the eastern fringes of the YMCA property,” McLelwain says. He adds that the water that is pumped out at the end of the process is practically drinking water and it also undergoes its own occasional monitoring.

“The net effect is, the dirty groundwater on the site, whether its from beneath the Y or beneath the northeast parking lot, is being collected, is being prevented from moving to any other property, its being fully captured, fully treated and discharged in accordance with Ministry of Environment and Climate Change approvals, ultimately to Oshawa Creek.”

And for Hans Jain, the president of Atria Developments, these systems are “above and beyond” protection and he’s content that his site is safe.

“You’ve got the best system in place. I don’t know what else you would want,” he says. “For us to do anything further wouldn’t make sense.”

The Atria development is slated for partial occupancy at the end of the year. The project is also the first in a two phase buildout that will include a second project on the western portion of the site.