Groundwater Remediation and RSC Filing

In 2009, XCG Consulting Limited (XCG) was contracted by Ontario School Boards’ Insurance Exchange (OSBIE) and the Durham District School Board (DDSB) to peer review the investigation and remediation activities at the Sunderland Public School (PS) in Sunderland, Ontario. During previous soil and groundwater quality investigations in the vicinity of a heating oil underground storage tank (UST) adjacent to the Sunderland PS, petroleum hydrocarbon (PHC)-impacted soil and groundwater was encountered on the Sunderland PS property and adjacent properties to the south. XCG was subsequently retained by the DDSB to take over the continued environmental management and remediation of the Sunderland PS. XCG is operating as the prime environmental consultant on the project. The remediation activities taken over from the previous consultant included the following tasks:

  • Groundwater monitoring and sampling activities to determine the current status of PHC impacts.

  • Meeting with the Ontario Ministry of the Environment and Climate Change (MOECC) York Durham District Office representatives on-site at their request.

Based on the analytical results from the groundwater sampling activities, residual PHC impacts were limited to one monitoring well at concentrations that marginally exceeded the MOECC generic site condition standards (SCS). XCG developed an exit strategy for the DDSB based on the analytical results. During the development of the exit strategy, XCG liaised with the MOECC York Durham District Office for the discontinuation of the remedial system.

With approval from the MOECC York Durham District Office, the on-site existing groundwater pump-and-treat system and infrastructure was removed from the property. The removal activities were coordinated with the DDSB to be completed over a weekend that also included a professional development day so no students would be present. The removal activities were followed by site restoration activities to return the former treatment area to an accessible field area of the school property.

XCG has coordinated a monitoring well decommissioning schedule with the DDSB and has completed two rounds of decommissioning activities. Twelve monitoring wells remain on-site and further decommissioning activities will be completed following closure at the site. XCG continues an annual groundwater quality monitoring program, as one monitoring well location continued to exhibit persistent petroleum hydrocarbon impacts marginally above the generic SCS.

Work by previous consultants during the Sunderland PS remediation activities included the filing of Records of Site Condition (RSCs) for surrounding properties impacted by the off-property migration of petroleum hydrocarbon impacts from the Sunderland PS. In 2015, it was discovered that the RSC for the adjacent property to the south was not previously acknowledged by the MOECC. XCG was retained by OSBIE to prepare and file the RSC for the adjacent property to the south, to meet the requirements of Ontario Regulation 153/04, as amended (O. Reg. 153/04). The filing of the RSC included the completion of a Phase One Environmental Site Assessment (ESA) and Phase Two ESA in accordance with O. Reg. 153/04 to support the filing of the RSC. During the RSC submission process, XCG liaised with the MOECC to satisfy the requirements of the RSC submission for filing.


The most recent annual sampling indicated all parameters were below the laboratory detection limits at all locations. It is anticipated that the 2018 annual sampling activities will confirm the successful remediation of the residual petroleum hydrocarbon impacts and the file can be closed with the DDSB and the MOECC. For the adjacent property to the south, the RSC was filed and acknowledged by the MOECC on December 8, 2016. In 2017, XCG decommissioned all remaining monitoring wells from the RSC property and the property was subsequently sold.

© 2020 by XCG Consulting Limited


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