Background

Concentric was assigned to the insurance claim and was requested to delineate the extent of impacts to soil and groundwater due to a fuel oil release from a fitting in the fuel line located adjacent to the furnace in the basement of the residence. Concentric was also required to provide recommendations for the remediation of the site to comply with the Technical Standards and Safety Association (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 release (source area) in the basement and surrounding the sump discharge area located northwest of the residence for offsite disposal;
• Advanced four boreholes and completed three of those boreholes as monitoring wells to delineate fuel oil impacts in the soil and groundwater beneath the site;
• Inspected and sampled the residential water supply for signs of fuel oil impacts;
• 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,
• Sampled groundwater from all onsite monitoring wells and the water supply well periodically to assess groundwater quality.

Key Challenges

The key challenge with this project was maintaining control of water levels coming into the basement excavation while manually excavating impacted material due to a high groundwater table at the time of the excavation. As such every effort was made to complete this remedial excavation as quickly as possible to minimize the impacts to infiltrating groundwater.

Key Personnel

Project Director: Robert Hoad, C.Tech., CMI
Project Manager: Eric Shilts, P.Geo. (limited)
Field Investigator: Grant Barker, B.Sc., GIT