Ehsan Momeni, P.Eng. and Christopher Paré, P.Geo.
Dragun Corporation
Implementation of Ontario Regulation 406/19 fundamentally changed the way excess soil is managed across the province. What was once commonly viewed as excavation material requiring disposal is now increasingly being repurposed as a resource and managed according to the requirements that apply.
The industry has developed a better understanding of regional soil conditions, naturally occurring constituents, use of statistical methods, salt-related impacts, and the practical challenges associated with managing large quantities of excavated soil.
What Did We Observe?
One important lesson is that elevated concentrations of certain metals may reflect regional geology (i.e., natural background) rather than contamination caused by human activities.
For example, arsenic and molybdenum may be encountered in native soils in the Windsor-Essex region, while vanadium is commonly identified in the marine clay deposits of eastern Ontario. Today, regional geological information, site history, soil characteristics and available background data are more frequently considered when evaluating these results. However, convincing the Ministry that these naturally elevated metal concentrations are representative of regional background conditions can still be challenging.
Additionally, some reuse sites are reluctant to accept soil containing reported exceedances, even when the results are consistent with natural background conditions within the region.
What Have We Learned from the data?
One notable outcome of the regulation has been the significant increase in soil characterization across Ontario.
This growing database may provide greater confidence in beneficial reuse and support decisions based on the overall quality of the soil rather than isolated results, if accepted by the regulatory community.
Statistical methods can also support this process. Where the regulatory requirements are met and the dataset is suitable, they may provide a more representative assessment of overall soil quality than relying solely on individual sample exceedances.
Greater familiarity with statistical methods could help practitioners make better use of existing information, support professional judgement, and reduce unnecessary disposal while maintaining regulatory compliance.
What New Challenges Have Emerged?
Salt-related parameters have become one of the more frequent drivers of excess soil management decisions. Elevated electrical conductivity (EC) and sodium adsorption ratio (SAR) are commonly encountered in areas affected by the long-term use of de-icing salts.
On some projects, EC and SAR, rather than petroleum hydrocarbons or volatile organic compounds, determine where the excess soil may be accepted and reused.
What Practical Challenges Remain?
Large, Blended Stockpiles
If the soil is combined before characterization is complete and testing later identifies a limited number of exceedances, it may no longer be practical to determine where the affected material originated or to delineate it within the stockpile.
In these circumstances, Qualified Persons (QPs) must evaluate the overall dataset and use professional judgement to determine an appropriate management strategy. Better planning before excavation, segregation of soil from different areas, and additional guidance for evaluating blended stockpiles help reduce this uncertainty.
Reducing Landfill Disposal
On Jan. 1, 2027, section 22 of the Excess Soil Regulation takes effect. In general, excess soil that meets Table 2.1 full-depth potable standards for residential, parkland or institutional use, or is of better quality, will be restricted from disposal at a landfill or dump.
Exceptions remain where the soil is required for operational uses at the landfill, such as cover, roads, or berms. Disposal may also be permitted in specific circumstances where a QP determines and documents that the soil is unsuitable for placement at a reuse site.
The restriction reinforces the need to consider reuse options early in project planning. Project teams may need additional time to characterize soil, identify receiving sites, document their soil-matching efforts, and coordinate transportation.
Looking Ahead
Experience with Ontario’s Excess Soil Regulation suggests that effective soil management requires more than comparison with individual analytical standards. It depends on early planning, appropriate characterization, regional geological knowledge, careful data interpretation and coordination among project owners, QPs, contractors, municipalities and reuse sites.
The growing volume of soil data has improved the ability to distinguish potential contamination from natural background conditions and to evaluate soil quality and reuse more effectively. At the same time, salt impacts, blended stockpiles, limited acceptance by the regulatory community of site-specific metal background values and limited time to identify reuse sites continue to create practical challenges.
The 2027 landfill restriction further emphasizes the regulation’s central direction. That is, soil that is suitable for reuse should be managed as a resource rather than automatically disposed of as waste. Continued technical guidance, regional research, statistical evaluation, and early communication will help improve consistency and cost-effectiveness, conserve landfill capacity, and support practical beneficial reuse across Ontario.
Dragun Corporation: Established in 1988 as an expert environmental services firm. We assist our clients with environmental issues, including Excess Soil, PFAS Assessment/Remediation, Vapour Intrusion Assessments, Phase I and II Assessments, Record of Site Condition, Environmental Compliance, and Expert Services.
Contact information: 519-948-7300 | in**@****un.com | www.dragun.ca
