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assessment of former electrical substation

assessment of former electrical substation
client
Enmax Corporation
location
Calgary, Alberta

Before decommissioning an electrical substation in Calgary, utility company Enmax hired Barr to assess the potential environmental liability associated with historical use of the property and to document possible impacts from current neighbouring property use. We conducted a limited Phase I environmental site assessment (ESA) and an initial Phase II ESA in general accordance with Canadian Standards Association (CSA) Z-768-01 and Z-769-00 environmental protocols.

The limited Phase I ESA identified the potential presence of petroleum hydrocarbon fractions associated with mineral oils used in the substation’s transformers, but the presence of PCBs was ruled out due to the age of the equipment and direct client knowledge. Based on the adjacent property’s use as a transportation maintenance yard, the study also identified the potential presence of salinity and metal impacts to soil and shallow groundwater. Barr performed an initial Phase II investigation to confirm the presence or absence of these contaminants of potential concern (CoPCs).

Completion of the initial Phase II investigation required working near high-pressure gas mains; proper offsets were established to allow the safe investigative drilling. Laboratory results verified the absence of CoPCs in soil above Alberta Tier 1 soil remediation guidelines for the intended land use. Shallow groundwater was not present. The lines of evidence—including the low CoPC concentrations in soil, subsurface lithology that consisted of low-permeability clay, and groundwater-flow direction—were used to demonstrate that no further investigation or remediation was necessary.