November 23, 2011

FISHER ENVIRONMENTAL LTD.

Fisher Environmental Ltd., of Markham, Ont., demolished two adjoining properties located at Trinity Street and Eastern Avenue, not far from Toronto’s Distillery District.

FEATURE | Demolition & Environmental Engineering

Toronto site remediation entails removal of 600 tons of soil

PETER KENTER

correspondent

Environmental remediation experts generally oversee projects on properties belonging to clients. Occasionally, all the pieces fall into place for the experts to buy and remediate a property of their own to prepare it for development.

That was the case for Fisher Environmental Ltd. of Markham regarding two adjoining properties located at Trinity Street and Eastern Avenue, not far from Toronto’s Distillery District. The combined size of the properties totaled a little more than 1,100 square metres.

“The land was formerly occupied by a car dealership and CN Rail, and surrounded by other industrial and commercial properties,” says Gordon Onley, business development manager with Fisher. “In the late 1800s<0x201A> a Consumers Gas Coal Gasification facility was located to the south and west of the site. There was a former CN Rail spike running through the site, presumably used for delivery of coal to Consumers.”

Fisher had conducted a preliminary site examination on behalf of the owner in 2006 and was approached by the client to purchase it in 2010.

During the subsequent Phase II Environmental Site Assessment completed by Fisher, soil samples demonstrated elevated concentrations of Polycyclic Aromatic Hydrocarbons (PAH).

“The type of cinders found there are typical of material from coal gasification and often used as fill all over Toronto,” says Onley. “It was recommended that the PAH-impacted soil be removed from the site and treated at a Ministry of Environment (MOE) licensed treatment facility.”

In early April 2010, 24 truckloads of contaminated soil weighing almost 600 tonnes were excavated from the site.

“You dig out what you think is enough soil because there’s no way of knowing how far the contamination may extend,” says Onley. “We examined the excavated area and took an additional 13 soil samples from the walls and floor of the open excavation.”

Five of the samples showed elevated concentrations of PAHs, lead, zinc and Petroleum Hydrocarbons (PHCs). The testing also showed that the cinder fill material extended underneath the on-site building. Fisher contracted Priestly Demolition Inc. to remove the entire one-storey building, including the foundation and associated debris in June of that year.

“Priestly is particularly good at recycling building materials, usually recycling 85 to 90 per cent of the components,” says Onley. “They completed the demolition in a matter of days.”

Fisher directed that an additional 875 tonnes of soil be removed and took 25 additional soil samples from the walls and floor of the excavation to find that the remaining soils on the site fell within MOE standards for Residential/Parkland/Institutional property.

“All of the contaminated soil was considered lightly impacted and was taken to a soil remediation facility, treated, and reused,” says Onley. “Although we were permitted to dump the soil into landfill, we felt it was more responsible to have it treated.”

Once the remediation was completed, a third-party environmental consultant confirmed the site soil conditions assessed by Fisher.

Onley notes that quick turnaround by MOE helped to speed permitting and approvals. “It can take a while for a property to be permitted when it goes from commercial and industrial to a more sensitive use, such as residential,” he notes.

Once approved by MOE, the property was sold to Streetcar Developments Inc. as the site for its proposed Trinity Lofts project.

Onley notes that the MOE has amended Ontario’s Brownfield legislation (Ontario Regulation 153/04, Records of Site Condition), effective July 2011.

“The amendments both streamline the approval process and make guidelines stricter for 65 per cent of contaminants we test for,” says Onley. “The new guidelines recognize advances in science’s understanding of the effects of contaminants on human health and our ecology.”

The guidelines also make provision for site-specific conditions. Using a new modified generic risk assessment model, applicants now have the option of showing that the site under assessment, while over the provincial standard, does not pose a risk to human health or the surrounding ecology,

“You may have levels slightly above guidelines for a couple of parameters, but due to the conditions at the site and the property’s intended use, it poses no risk to people in the area or the surrounding environment,” says Onley. “Formerly timelines for approval of a risk assessment might have taken in the neighbourhood of 18 months to two years, but under the streamlined approach it’s proposed that it may take as little as three to six months.”

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