Environmental Site Assessment

Understand the ground you build on: access the information you need to satisfy regulators and mitigate your site risks

As a property owner or developer, you need to fully identify and understand the subsurface environmental risks you may be assuming – and you may be required to deliver an Environmental Site Assessment (ESA) or Contaminated Site Assessment (CSA) to regulators. Our expertise can help you fulfill your obligations and avoid legal and regulatory surprises.

open field and sunny sky

Our service

We help you understand and manage subsurface environmental risks for both developed properties (brownfield sites) and undeveloped properties (greenfield sites) through a complete range of services: assessment, remediation planning, monitoring, and formal recording of compliance.

You may need an ESA or CSA as part of a property acquisition or corporate due diligence process, to maintain your operating permit or to mitigate risks arising from an activity or natural process. Whatever your reason for embarking on an assessment, our team has the technical capabilities and regulatory knowledge to help you complete the process effectively and act on the findings.

Every assessment we carry out is overseen by a senior professional with experience in identifying unusual or complex issues, and our staff have both the credentials (P.Geo, P.Eng, Qualified Person) and the experience to engage effectively with regulators. If an assessment process identifies a problem, we can draw on a wide range of technical expertise from across RWDI to develop a mitigation strategy. For example, our experts in ventilation can advise on dealing with accumulated or migrating vapor. We excel in solving complex issues, such as supporting a legal action involving external contamination from two sources or devising remedial action plans to address multiple contaminants.

Services include:

Environmental Site Assessment

  • Phase One Environmental Site Assessment.  Used to determine whether the potential for an environmental problem exists at a site. Includes a review of available historical documents for the site and surrounding properties, a thorough site reconnaissance to evaluate existing conditions, and interviews with knowledgeable site representatives and/or willing neighbors and past owner.

  • Phase Two Environmental Site Assessment. Builds on the results of a Phase I ESA to confirm whether a problem exists at a site. Can include both nonintrusive and intrusive sampling programs to address any potential contaminating activities (PCAs) noted within the Phase I ESA. Nonintrusive sampling is typically prescreening with electromagnetic or ground penetrating surveys. Intrusive sampling can include drilling, test pit advancement, and sampling of soil/groundwater/surface water/soil vapor, as appropriate. An analytical testing program is typically carried out to verify concentrations of contaminants of concern and compare them to regulatory criteria.

  • Delineation of the Extent of Contamination and Remedial Plan Development. Conducted to determine how big a problem is at a site. Intrusive and/or nonintrusive investigations establish the extent of contaminants as verified by the Phase II ESA.

ground water assessment

Remediation Planning and Monitoring

  • Development of an appropriate remedial action plan based on the extent and nature of the contamination found in the assessment. This phase includes a verification sampling program to monitor the remedial effort and assess their effectiveness.

Record of Site Condition

  • In some cases, owners or developers must file a Record of Site Condition (RSC). Under Ontario Regulation 153 (O. Reg. 153/04), the Ontario Ministry of the Environment, Conservation and Parks requires a land owner to file an RSC if land use changes from a less sensitive use (industrial, commercial) to a more sensitive use (residential, parkland). Our team includes specialists (designated “Qualified Persons” by regulators) who are authorized to file an RSC upon completion of either the phased site assessment described above and/or a remediation process. Under certain circumstances, the local municipality may also require an RSC.