Environmental Services

On-Site and Excess Soil Management

On December 4, 2019, the Ontario Ministry of Environment, Conservation and Parks announced that the long anticipated regulation governing the sustainable reuse of excess soil in the province (O. Reg. 406/19) [1], would come into effect starting July 2020. Over the following 2 years, the regulation would see gradual adoption of its various elements, allowing ample transition period for current projects and new or planned activities.

The specific requirements under O.Reg. 406/19, including numerical standards, are outlined in the Rules for Soil Management and Excess Soil Quality Standards [2] document. These rules outline key components of the regulation that effectively make up the requirements. These include:

  1. The assessment of past uses (a limited scope Phase I)
  2. Sampling and Analysis Plan
  3. Soil Characterization Report (a limited scope Phase II)
  4. Excess Soil Destination Assessment Report
  5. Tracking System
  6. Applicability of soil quality standards.

The focus of this technical bulletin will be to summarize the sampling, analysis and soil quality standards requirements.

It is important to keep in mind that O.Reg. 406/19 goes hand in hand and often references O.Reg. 153/04 [3]. Tables 1 through 9 of O.Reg. 153/04, as well as the Analytical Protocols document referenced therein, are part of the requirements of O.Reg. 406/19.

Before diving into the details of the various components, it is important to consider the main decision point with regard to excess soil: the threshold between small volume and volume independent projects. This threshold is established at 350 m3 of excess soil. The number of samples to be collected, mandatory analyses and applicable numerical standards tables will be dependent on whether the excess soil volumes are less than or greater than 350 m3.

Sampling & Analysis Plan

Contaminant characterization under O.Reg. 406/19 is strictly focused on the quality of soil and not groundwater. As such, the regulation provides the option of either in-situ sampling or stockpile sampling, although the former is the recommended approach.

The minimum number of samples to be collected is dependent on the total volume expected to be excavated. It should be noted, that the incremental number of required samples decreases as the excavated volume increases, based on assigned thresholds as identified below.

Table 1: Minimum Number of Samples Required

VOLUME THRESHOLD MINIMUM NUMBER OF SAMPLES FOR BULK SOIL ANALYSIS MINIMUM NUMBER OF SAMPLES FOR LEACHATE ANALYSIS
SMALL VOLUME PROJECTS VOLUME INDEPENDENT PROJECTS
≤350 m3 ≥ 3 samples - -
≤350 m3 to <600 m3 - ≥ 3 samples ≥ 3 samples
>600 m3 to <10,000 m3 ≥1 sample for each additional 200 m3 within threshold limits 3 samples + 10% of Bulk Soil samples collected
>10,000 m3 to <40,000 m3 ≥1 sample for each additional 450 m3 within threshold limits
>40,000 m3 ≥1 sample for each additional 2,000 m3 beyond threshold limit

The thresholds above must be applied in a gradual approach, as the excavation advances and the volume of excess soil increases. For example, for an excess soil volume of 5,000 m3 the minimum number of samples is 25:

  • At least 3 samples for the first 600 m3; +
  • At least 22 samples for the remaining 4,400 m3 (collected at a rate of 1 sample / 200 m3)

Sampling for the purpose of characterizing excess soil is ideally completed in-situ. In this instance, 350 m3 can be visualized as grids of approximately 7 m x 7 m and 7 m depth from surface.

Soil samples should be representative of the highest concentration of contaminants of potential concern (COPCs) on site, through both lateral and vertical stretches. The regulation prescribes a minimum number of samples to be collected, depending on soil volume excavated, as well as a minimum list of analytical requirements. These are outlined in Table 2 below for two scenarios of excess soil that the regulation applies to:

  1. Surface and subsurface soils
  2. Storm water management ponds

Table 2: Minimum Analytical Requirements

SURFACE AND SUBSURFACE SOILS STORM WATER MANAGEMENT PONDS
Metals (including hydride forming metals)
Benzene, Toluene, Ethylbenzene, Xylenes (BTEX)
F1 (C6-C10) Petroleum Hydrocarbons
F2-F4 (C10-C50) Petroleum Hydrocarbons
- Polycyclic Aromatic Hydrocarbons (PAHs)
pH
- Cyanide (WAD)
Leachate Analysis (conditional on contaminants of potential concern being identified by the QP, the volume of excess soil exceeding 350m3 and applicable standards) Leachate Analysis is always required for metals and hydride-forming metals 

When is Leachate Analysis Required?

The purpose of leachate analyses is to provide additional concentration data for contaminants for which soil to groundwater component values are not derived. This means that, in the absence of groundwater data, leachate analysis provides an indication of the level of contaminant risk to receptors.

For small volume projects (i.e. ≤350m3) leachate analysis is not required.

Leachate analysis is required for all volume independent projects (i.e. >350 m3) and whenever a contaminant of potential concern (COPC) is identified by the qualified person (QP). In addition, whenever O.Reg. 406/19 is applied to storm water management ponds, leachate analysis for metals and hydride forming metals is always required.

If leachate analysis is required, there is a minimum number of samples applies, as per Table 1, above. The minimum requirement for leachate samples is closely correlated to the minimum number of samples for bulk analysis. Leachate analysis must also be performed on samples representative of the highest bulk concentration. Therefore, it may be prudent to hold samples for leachate analysis until the QP has reviewed the bulk results.

Acceptable leaching methods include the Synthetic Precipitate Leaching Procedure (SPLP) as per EPA Method 1312, Toxicity Characteristic Leaching Procedure (TCLP) as per EPA Method 1311 or an alternative method that has received Director’s Approval.

Applicability of Excess Soil Standards

O.Reg. 406/19 makes use of three different sets of standards, depending on the size of the project and analysis type. Below is a summary of the standards tables and scenarios under which these are applicable.

Table 3: On-Site and Excess Soil Standards

TABLE DESCRIPTION TABLE NUMBERS
SMALL VOLUME (≤350m3) VOLUME INDEPENDENT LEACHATE SPECIFIC TABLES
Full Depth, Background Table 1
Full Depth, Potable Table 2 Table 2.1 Table 2.1
Full Depth, Non-potable Table 3 Table 3.1 Table 3.1
Stratified, Potable Table 4 Table 4.1 Table 4.1
Stratified, Non-potable Table 5 Table 5.1 Table 5.1
Full Depth, Shallow Soil, Potable Table 6 Table 6.1 Table 6.1
Full Depth, Shallow Soil, Non-potable Table 7 Table 7.1 Table 7.1
Full Depth, within 30m of a water body, potable Table 8 Table 8.1 Table 8.1
Full Depth, within 30m of a water body, non-potable Table 9 Table 9.1 Table 9.1

For a standard to be met on a given parameter, two options are available for evaluating laboratory results:

  1. Single point compliance
  2. Statistical data assessment

Single point compliance means that any given parameter on a single given sample is less than or equal to the applicable standard; OR the average of two or more samples (collected from the same sample location and same depth) is less than or equal to the applicable standard.

To use the statistical method for evaluating results against the soil quality standards, several requirements must first be met:

  • A minimum of 20 samples are collected and as many analytical data points available
  • 90% of the data points meet the standard based on “single point compliance”
  • The mean of the data points (upper 95% confidence interval) meets the standard
  • No parameter exceeds the assigned ceiling value
  • Note: This approach cannot be used on pH data

In instances where leachate analysis is a requirement, it is important to identify which parameters require testing. Parameters tested in bulk soil samples, that require leachate analysis are marked with “a” in the Generic Small Volume and Volume Independent tables. In addition, parameters requiring leachate analysis are not consistent across the different tables and property use scenarios, so a clear understanding of the applicable standards is required at the project planning stage. Unlike O. Reg. 153/04, where laboratories are required to report all parameters within a parameter group defined in the Analytical Protocols[4] document, leachate data reported in support of O.Reg. 406/19 may be reported for individual or selected parameters from a parameter group.

 

References

[1] Ontario Ministry of Environment, Conservation and Parks. 2019. Regulation 406/19: On-Site and Excess Soil Management. Environmental Protection Act, R.S.O. 1990, c. E. 19.

[2] Ontario Ministry of Environment, Conservation and Parks. 2019. Rules for Soil Management and Excess Soil Quality Standards. ISBN 978-1-4868-3715-1.

[3] Ontario Ministry of Environment, Conservation and Parks. 2004 (amended 2019). Regulation 153/04: Records of Site Condition – Part XV.1 of the Act. Environmental Protection Act. R.S.O. 1990, c. E. 19.

[4] Ontario Ministry of the Environment. 2011. Protocol for Analytical Methods Used in the Assessment of Properties under part XV.1 of the Environmental Protection Act. Laboratory Services Branch.