Common Contamination Risks
The risk of your land being contaminated is real. Urban sprawl pushes contractors and promoters to develop more and more remote areas, or locations previously used for other purposes. The best way to identify all environmental risks associated with a property is to carry out a Phase I Environmental Site Assessment. This study compiles an inventory of current and previous site activity and history to determine risks. Certain properties reveal potential indicators of contamination calling for investigation in a Phase II Environmental Site Assessment.
Contaminants by Era
Each successive era in Québec is characterized by its activities. 18th century activities were predominantly related to the fur trade, agriculture and forestry. Pollution as we know it today did not yet exist. In contrast, at the end of the 19th century and beginning of the 20th century, new industries appear. In more developed regions, these are, notably: tanneries, automotive, aluminum and chemical products, while industries exploiting natural resources, such as pulp and paper and hydroelectricity, establish facilities in more remote, less-industrialized areas. Furthermore, it is not only industries that evolve, but also legislation.
Environmental risks common to their era are present throughout all completed projects. The following list is not exhaustive but represents a substantial portion of the concerns raised since the company was founded in 1995:
1. Aboveground Storage Tanks (ASTs)
In the 20th century, a new generation of heating began as heating oil supplanted coal. To power the furnaces, storage tanks containing heating oil were used. The tanks were also used to store petroleum products other than heating oil, and/or chemicals used in commercial or industrial manufacturing processes. These storage tanks could be installed inside or outside of buildings. Equipment service life can vary depending on exposure to extreme conditions. According to our observations, outdoor storage tanks can be kept directly on the ground, on a stone cover, on asphalt or on a concrete slab, while indoor tanks can be kept on a concrete slab or directly on packed earth. Depending on the surface on which the tank is kept, leaks are not always visible. In our experience, a single daily drop over a long period of time can cause significant contamination.
More conclusive indicators of an eventual leak include:
- Odours
- Staining on the ground and tank
- Dated manufacturing year and materials
- Anomalous inventory
When a storage tank is subject to removal, it is recommended to remove the vent and fill pipes connected to its exterior to eliminate the risk of fortuitous filling. This type of accident can lead to complex and costly environmental remediation work.
2. Underground Storage Tanks (USTs)
With the advent of heating oil, some business owners opted for a UST, as was the case for the diverse petroleum and chemical product storage industries. One valuable example is the gasoline service station. Initially, the technology used for tank manufacturing was not what it is today; it continues to evolve, and consequently the risk of a leak is particularly critical with respect to superannuated manufacturing dates. It is also important to mention that not all tanks are identified or listed. However, certain elements can indicate the presence of a storage tank:
- Surfaces where the asphalt overlay has been altered
- Vent and/or fill pipes still present
- Historical site documentation indicating the presence of a storage tank or former tank (for example, fire insurance plans, city permits, floor plans, etc.)
- No proof of tank removal, and/or no document confirming environmental quality compliance of residual soil.
Since they are underground, eventual leaks (via corrosion or a manufacturing defect) can remain unnoticed for a considerable lapse of time, thereby causing soil and groundwater contamination. Nevertheless, the presence of a UST does not automatically translate to contamination; only a Phase II Environmental Site Assessment can confirm or rule out eventual contamination.
3. Illegal Dumping
In isolated regions, wooded areas, natural hollows or on less-traveled paths, there is a risk of illegal dumping. These repositories can be contaminated soil or waste materials appearing on a site that is not designed to collect such materials. According to a provincial government statement, there were 1009 illegal landfills on state land between April 2021 and March 2022. 224 illegal landfills were cleaned up during this same period. These dump sites represent an environmental risk for the sites on which they are located as well as adjacent properties since liquids can leak, toxic substances can spill and contaminants can be released into the environment. These statistics do not include private and/or municipal properties and do not reflect the full extent of illegal dumping in Québec.
4. Backfill
A diversity of landforms is found in Québec, such as mountains, valleys, plains, hills and plateaus. However, some variations in relief features can be a result of site raising or levelling operations. These operations may have involved importing materials, resulting in environmental risk if the added materials are of an unidentified nature and origin. In the past, environmental awareness was not what it is today; it is possible that contaminated materials (mine tailings, waste, contaminated soil, etc.) were used to backfill properties. In certain regions, such as Thetford Mines, the issue of historical backfill containing asbestos is well-known, and specific directives have been added to the MELCCFP Response Manual – Soil Protection and Contaminated Sites Remediation to address the resulting challenges. If the source is not known and the soil is not assessed, the material presents an environmental risk, or an area of potential environmental concern (APEC).
As environmental professionals, the primary objective is to paint an accurate and concise portrait of the subject property by presenting pertinent information and establishing the eventual presence of environmental risk connected to backfill.
5. Fire
In the event of a fire, contaminants are released into the environment, namely in the soil and groundwater. Contaminants are also transmitted through the water from fire hoses. It is therefore important to determine preferential flow paths and establish the zones most at risk of becoming contaminated. Additionally, the type of activity taking place on the site of the fire can have an impact via chemicals or other products employed in the context of these activities.
Environmental professionals have a responsibility to conduct their work diligently, ensuring all necessary elements have been considered to determine whether any of them raise one or more environmental concerns. If contamination is suspected during a Phase I ESA, a Phase II ESA will be recommended to investigate, normally via soil sampling.
