Case Study

Airport: Government Contamination Risk Assessment (CAN)

The airport is being transferred from Federal guardianship to the City of Whitehorse, and as such, PWGSC wished to assess the human health risk associated with the hydrocarbon contamination associated with a former underground storage tank area to the southwest of the Terminal Building and northwest of the Control Tower.


Whitehorse, Yukon


Public Works and Government Services Canada (PWGSC)



Project Objectives:

The primary objective of the environmental site assessment was to complete a groundwater investigation and drilling program to delineate the petroleum hydrocarbon and CFC-11 contamination.

The objective of the risk assessment was to assess potential adverse health effects to human health and ecological receptors associated with contamination identified in soil, groundwater and soil vapour at the site. The risk assessment also served as the basis for risk management options for the site.

Our Role

SLR undertook the following works:

  • Phase I ESA: Hydrogeological and detailed groundwater investigation to create a current contamination profile. Groundwater and vapour sampling was conducted at -40OC, and soil vapour wells were installed indoors
  • Phase II Environmental Site Investigation: Drilling program to delineate groundwater contamination, to conduct a soil vapour investigation and to support the risk assessment
  • Phase III Environmental Site Investigation: Seasonal vapour and groundwater samples were collected, and preferential pathways were investigated
  • Risk Assessment: Exposure estimations were conducted for human health potentially exposed to groundwater containing PAHs, LEPHw, and dissolved arsenic, iron, manganese, and uranium above applicable regulatory standards. Exposure to TCE in vapour was also assessed
  • Risk Management Planning: SLR provided remedial/risk management options taking into consideration the behaviour of contaminants of concern and restrictions based on current site use