Phase I and II ESA

Project Description:

ECOH was retained to conduct a Phase I and II ESA for a vacant commercial property formerly occupied by an automotive repair facility and gas station.  The Site has been dedicated as a proposed location for the development of a future fire hall.  As part of the development process, a Record of Site Condition (RSC) under Ontario Regulation (O. Reg.) 153/04 (as amended) was required as per the internal permitting/development policies.  As such, ECOH was retained to undertake the ESAs to support the submission of a RSC with the Ontario Ministry of the Environment and Climate Change (MOECC).

The Phase One ESA identified various PCAs and APECs associated with the historic auto repair and fuel distribution activities conducted at the site.  In addition, because of a result of a review of historic ESA reports, ECOH identified historic petroleum hydrocarbon (PHC) impacts in the soil and ground water.  As a result of the Phase One ESA findings, ECOH proceeded with the Phase Two ESA in September 2015.  To achieve the objective of the Phase Two ESA, ECOH advanced twelve (12) boreholes and eight (8) test pits, installed over 12 monitoring wells and collected over 30 soil samples and 12 ground water samples for chemical analysis of PHCs, VOCs, PAHs, and metals/inorganics.

The soil analytical results confirmed that subsurface soils in select areas of the site were impacted with select PHC or metal concentrations above the applicable Table 3 SCS.  As the impacts were noted to be present in areas of reworked soil or in the vicinity of former remedial excavation limits, the soil exceedances identified within the subsurface soils appeared to correlate with the historical demolition and remedial activities undertaken at the site.  The ground water analytical results confirmed that ground water beneath the site was impacted with chloride concentrations above the applicable Table 3 SCS.  The chloride concentrations which exceeded the applicable MOECC Table 3 SCS were widespread and encompassed the majority of the site.  Based on the contaminant types and quantities in both medias (i.e. soil and ground water), ECOH recommended that the client manage the identified impacts via both risk assessment and ex-situ remediation (i.e. removal).  More specifically, it was recommended that the soil impacts be addressed via direct source removal (i.e. excavation) and the ground water impacts be addressed via the completion of a MOECC O. Reg. 153/04 (as amended) Modified Generic Risk Assessment (MGRA).  The rationale to addressing the soil impacts via direct source removal is to ensure that all soil impacts are removed such that future risk management measures are not required at the Site (e.g. cap barriers, vapour barriers, monitoring in perpetuity, etc.).  The rational to addressing ground water impacts via a MGRA is to ensure that chloride impacts are addressed in a timely and technically practical and cost efficient manner.  In order to conduct the MGRA, ECOH is scoped to return to the site in the summer of 2016 to collect additional hydrogeological and chemical data which will support the MGRA which will be conducted by a sub-contractor.

In addition, ECOH is currently assisting with the development of a remedial action plan and the development of engineering specification documents for the tendering of the soil remediation by a qualified remedial contractor.