Contaminated Site Management
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Contaminated Site Management
We oversee the environmental characterization of a site, the design of its remediation plan and the management of excavated soil, through to demonstrating that the site complies with its intended use. The work always starts with the site's history, never with drilling.
We work with developers, industrial owners, municipalities and their lenders, in a setting where the study has to stand up before the ministry, the notary and the buyer who will finance the building.
- EQA · Division IV.2.1Characterization and remediation obligations
- 2024 GuideSite characterization guide, current edition
- Traces QuébecMandatory traceability of excavated soil
I
The key steps in managing a site
A site doesn't become compliant because it has been excavated. It becomes compliant because it has been demonstrated, with supporting documents, that it meets the criteria for its use. The order of the steps isn't administrative, it's legal: what wasn't characterized before the work can't be characterized afterward.
Environmental site assessment (Phase I)
Review of titles, aerial photographs, permits and ministry records, followed by a site visit and interviews. This establishes what the site has been used for and which areas are suspect. No drilling at this stage: Phase I is precisely what tells you where to drill.
Site characterization (Phases II and III)
Test pits, boreholes and observation wells, sampling of soil and groundwater, analyses in an accredited laboratory. Phase II confirms that contaminants are present; Phase III delineates their extent, which is the only way to put a cost on them.
Remediation plan
Design of the work that will make the site compliant with its future use (residential, institutional, commercial or industrial) and submission to the ministry when the law requires it. This is the document that sets the project's real budget, not the estimate made before drilling.
In situ treatment
Neutralizing or breaking down contaminants directly in the soil, by biological, chemical or physical means, without major excavation: chemical oxidation, bioventing, biosparging, vapour extraction, monitored natural attenuation. It pays off when excavation is impossible: under a building, under a street, under a utility line.
Off-site management (ex situ)
Excavating contaminated soil and transporting it to an authorized treatment or disposal site. It's the fastest and most predictable method, but also the one whose cost is most exposed: levies, transport, availability of receiving sites.
Traceability of excavated soil
Since January 1, 2023, all contaminated soil leaving its original site must be tracked in Traces Québec, from loading to the receiving site. The project owner is covered just as much as the carrier.
II
What is environmental characterization?
It's the study that establishes whether a site is contaminated, with what, how deep and how far. It compares measured concentrations to regulatory limit values, and that comparison, not the look or smell of the soil, determines what you are allowed to do with the site and what it will cost to remove the soil.
The principle fits in one sentence. Soil isn't judged dangerous in absolute terms, but in relation to its intended use: the same sample can be acceptable under an industrial parking lot and prohibited under a daycare.
The A, B and C criteria express this scale, and four situations arise.
- Criterion A: corresponds to the background level, meaning the region's natural soil. Exceeding A isn't necessarily a problem, but it already triggers traceability obligations when the soil is excavated.
- The A-B range: generally compatible with residential use. It's the threshold targeted when an industrial site is converted to housing.
- The B-C range: associated with commercial and industrial uses. A site in this range can be compliant without being decontaminated, as long as its use doesn't change.
- Above C: the soil can no longer be left in place or disposed of freely, and its disposal cost changes by an order of magnitude.
III
The situations that call for a study
An owner doesn't order a characterization out of curiosity. Here are the four triggers we see most often, and what each one actually requires.
- Sell or finance
The buyer or lender requires due diligence
Here the study isn't required by law but by the contract. Not having one costs you a discount on the price, a condition precedent, or an outright refusal of financing.
- End an activity
A designated activity is ending on the site
The operator of an industrial or commercial activity designated by regulation must have the site characterized when it permanently ceases operations (s. 31.51 EQA). If limit values are exceeded, a remediation plan follows and a notice of contamination is registered in the land register.
- Change the use
An industrial site becomes residential or institutional
Converting a site that hosted a designated activity triggers the same characterization obligation (s. 31.53). It's the most common trigger in urban Montreal, where the old garage becomes an apartment building.
- Discover
Contamination appears during construction
Discoloured soil, a smell of hydrocarbons, a forgotten tank. Excavation stops, and what happens next depends entirely on how quickly what has just been uncovered is characterized.
IV
Our approach, from the site's history to the final report
Order matters. A drilling program decided before the historical review gets redone, and a budget set before delineation never holds.
- Scoping and historical reviewWhat the site has been used for, what the neighbouring sites have been used for, what the municipal and ministry archives say. The quality of everything that follows depends on this step, and it's the one most often wrongly cut short.
- Investigation programNumber, location and depth of boreholes, analytical parameters, observation wells. We design the program and have it carried out by accredited drillers and laboratories; supervision, interpretation and signature stay with us.
- Interpretation and delineationComparison to regulatory limit values, delineation in plan and in depth, volume estimates by contamination range. This is where the project's cost stops being an assumption.
- Scenarios and trade-offsIn situ treatment, excavation, risk management, or a combination of the three. We compare the options with their real consequences: timeline, disposal cost, site constraints, residual restrictions on use. The choice is the client's, but it's made on the numbers.
- Remediation and final reportSupervision of the work, traceability follow-up for outgoing soil, post-remediation characterization and the final report. It's the final report, not the end of the work, that makes the site defensible.
V
What you receive
A contaminated site study has to serve three audiences: the ministry that authorizes, the lender or notary who secures the transaction, and the contractor who will excavate. We write for all three.
- The characterization report: raw data, laboratory certificates, borehole location plans and the control tables required by the ministry.
- Delineation plans: the extent of contamination in plan and section, with estimated volumes by contamination range.
- The remediation plan: when required, written to be approved rather than commented on three times.
- The estimate of soil management costs: including the levies that apply to the management method chosen, because that is often the item that decides the scenario.
- A decision summary: for the owner, the board or the lender, explaining what is at stake and the options without requiring training in geochemistry.
Reference framework
- Contaminated Sites
- EQA, Division IV.2.1
- Limit values
- LPRR, Schedules I and II
- Methodology
- Site characterization guide (2024)
- Remediation
- Ministry intervention guide
- Excavated soil
- Traceability regulation · Traces Québec
- Signing of documents
- EQA, s. 31.42
The applicable requirements vary with the intended use, the site's history and the receiving environment. We confirm the exact framework when we scope the assignment, before finalizing the investigation program.
VI
FAQ
What's the difference between a Phase I, a Phase II and a Phase III?
Phase I is a document review: archives, aerial photographs, permits, a site visit and interviews. It concludes whether suspect areas are present or not, without any drilling. Phase II tests those hypotheses with boreholes and laboratory analyses: it tells you whether there is contamination and what kind. Phase III delineates that contamination in plan and in depth. Many projects stop after Phase I; those that go further need Phase III to put a cost on anything.
How much does contaminated soil management cost?
The cost of the studies is predictable; the cost of disposal is not, and it dominates the budget. Since January 1, 2024, a levy has been added to the price charged by the receiving site: in 2026, it is $5 per tonne for soil sent for treatment, compared with $12 per tonne for landfilling. On top of that come transport, traceability fees and the actual availability of sites. That is why Phase III delineation is rarely wasted money: it turns an assumed volume into a measured one.
How long does the process take?
The technical work is rarely the bottleneck. A Phase I takes a few weeks, much of it spent waiting for access to archives. Routine laboratory analyses take about a week, less on a rush basis. What stretches a schedule is the ministry review: a remediation plan submitted to the ministry is counted in tens of business days, and the clock stops every time a clarification is requested. A project that plans for this delay simply absorbs it; a project that ignores it pays for it in interest.
Who can sign a characterization study?
Since April 2023, the ministry checks the signatory's qualifications. Section 31.42 of the Environment Quality Act reserves the signing of characterization studies, remediation plans and notices registered in the land register for a member of a professional order (the Ordre des ingénieurs du Québec is one) or a person certified as an environmental site assessor under the ISO 17024 standard. A study signed by someone who is not authorized is rejected, whatever its technical quality.
Do you do the drilling yourselves?
No, and that's a deliberate choice. We design the investigation program, supervise its execution and sign its interpretation; drilling and analyses are entrusted to accredited drillers and laboratories. That keeps us independent of the volume of soil excavated, which matters when the assignment is precisely to establish how much has to come out.
Does a contaminated site always need to be decontaminated?
No. The point isn't to make the soil clean, but to make it compatible with its use. A commercial site with concentrations in the B-C range can be fully compliant as long as its use doesn't change. What changes everything is a conversion to a sensitive use (housing, daycare, school) or excavation, which takes the soil off its site and triggers obligations that didn't exist while it stayed there.
What happens if we have to excavate near an existing building?
This is where our background as a structural firm makes a difference. Removing contaminated soil along a foundation, under a slab or near a party wall raises questions that are no longer environmental: excavation stability, shoring, underpinning, settlement caused by groundwater drawdown. We design the sequence of work with these constraints in mind, instead of discovering them when the excavator is already in the ground.
Next step
A site to check, a project to get moving?
Tell us what the site has been used for, what you want to do with it and by when. We'll tell you which study actually answers the question, and what to gather before starting.
- Firm
- GC4I Inc., structural engineers
- Office
- 8350 Christophe-Colomb Avenue, Suite 18, Montreal
- Service area
- Montreal, South Shore, North Shore and across Quebec
- contact@gc4i.ca
The standards cited are those applicable in Quebec when this page was last updated. The exact framework depends on the intended use, the site's history and the requirements of the competent authority.