XCG was retained to conduct a Phase Two Environmental Site
Assessment (ESA) to delineate and quantify subsurface soil and
groundwater impacts on a 30 acre property, occupied by a large plant that
had manufactured steel office furniture and other steel products since the
early 1930s. This property had been acquired by Transamerica as a result
of a foreclosure, and required decommissioning and demolition prior to being
sold and redeveloped.
The subsurface investigations on this site detected elevated concentrations of
trichloroethylene (TCE) and other related compounds in the groundwater within a
confined aquifer beneath one area of the site. The confined aquifer is used as a
source of drinking water by the municipality, approximately 800 metres from the
subject site. The confined drinking water aquifer consists of a layer of primarily
sand, which is overlain by an aquitard of silty clay till about five to fifteen metres
thick, which in turn is overlain by a surficial aquifer unit of granular soils about five
to ten metres thick. The TCE concentrations found in groundwater samples from
the confined aquifer ranged from about 3,500 μg/L to 15,000 μg/L.
XCG conducted off-site deep drilling to delineate the horizontal and vertical
extent of the TCE plume. Twenty-six deep monitoring wells were installed, with screens placed in the confined drinking water aquifer at depths ranging from 30 to 50 metres below the ground surface. The monitoring wells included single monitoring wells, as well as clusters of two or three wells screened at different depths within the deep aquifer.
Following the delineation of the plume, a pump-and-treat system using a UV
oxidation system as the groundwater treatment process was installed. Subsequently,
the property was redeveloped as a senior’s retirement village (Luther Village) under
the management of MacNaughton, Hermsen, Britton, Clarkson (MHBC) Planning Ltd.