Residential Fuel Oil Spill, Lefaivre, ON


21 months




Concentric was assigned to the claim and was requested to delineate the extent of impacts to soil and groundwater from a fuel oil release from an out-of-use above ground storage tank (AST) located at the southwest exterior corner of the residence. Concentric was also required to provide recommendations for the remediation of the site to comply with the Technical Standards and Safety Authority (TSSA) order.

Approach & Methodology

Concentric conducted an initial inspection of the subject property to help aid in the development of a preliminary Conceptual Site Model (CSM). Based on the CSM:
• Excavated impacted soils in the vicinity of the AST (source area) for off site disposal;
• Advanced twelve boreholes and excavated four test pits for the delineation of the fuel oil impacts in the soil;
• Inspected the drainage tile discharge for visual and olfactory signs of fuel oil impacts;
• Collected surface soil samples below areas of stressed vegetation (surface staining);
• Conducted an inspection of shoreline for visual (sheen) and olfactory evidence of fuel oil impacts;
• Conducted an inspection of the on-site and neighbouring supply water wells for visual and olfactory evidence of fuel oil impacts;
• Removed liquid phase hydrocarbons from the on site supply well, followed by the removal, cleaning and replacement of the concrete well casing;
• Excavated all impacted soils for off-site disposal, including the collection of guidance soil samples to direct the excavation and verification soil samples for laboratory analysis;
• Backfilled the excavated area with clean imported fill; and,
• Installed post remediation monitoring wells for the collection of groundwater. In addition, Concentric completed a structural assessment and provided structural drawings for the reinstatement of the house and wood deck.

Key Challenges

Soil and groundwater contamination levels were required to be below relatively conservative standards since the site is within 30 metres of a water body and the well water was being used for potable water. Although the residence was temporarily relocated during site remediation, there was limited access within the site for the excavation equipment and machinery.

Key Personnel

Project Director: Allan Murray, P. Eng.
Project Manager: Eric Shilts, P. Geo. (limited)
Field Investigator: Paul Park, CET, CMI
Field Investigator: Grant Barker, GIT


Environmental Site Investigation Remedial Action

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