1) New Excess Soil Standards…

1) New Excess Soil Standards Tables 2.1 to 9.1.

Many concerns have been raised since the first development of volume independent excess soil standards a few years ago. These additional tables and applications will be confusing. It also poses some conflicting scenarios for future, especially for the instances when excess soil meets volume independent standards (Table 2.1 to 9.1) but fails small volume standards (Table 2 to 9).

With additional leachate screening levels and ceiling values, it will make excess soil characterization a difficult task. It is understood the whole excess soil regulation is to promote re-use of precious soil resources and site re-development, not to labour investigation process and increase unnecessary costs.

It is suggested that we shall re-evaluate on development of these volume independent standards and integrate with existing standards. Instead of 2 sets of standards, one (1) updated set of standards will serve excess soil investigation better and improve beneficial reuse of excess soil, meanwhile to protect human health and environment.

2) Mandatory Leachate Analyses Requirements

The leachate analysis requirements for a minimum of 3 samples and a frequency of at least 10% of the bulk samples are too excessive and would drive investigation costs significantly.

• Leaching from soil to groundwater has been included in the soil standard development, which indicates no adverse effects if bulk samples meet the site condition standards.
• With my over 15 years’ experience in environmental consulting, I have not seen any leachate samples exceeding Reg. 347 Schedule 4 criteria.
• In Soil Rules, no rationale of this mandatory leachate analysis requirements and leachate screening levels were provided. It seems that the leachate screening levels were developed based on potable and non-potable groundwater uses, not on property uses (more or less parameters?). Environmental consultants need to have a better understanding of these excessive requirements and scientific evidences behind.

3) Excess Soil Characterization

In Soil Rules, an excess soil characterization seems to be an independent report required instead of an additional/confirmatory investigation further to Phase 1 and 2 Environmental Site Assessment (ESA). This investigation could be repetitive and excessive due to these sampling and analysis requirements, which have been included in Phase 1 and 2 ESA required in the current Reg. 153/04, as amended.
• The reason to conduct excess soil characterization is proposed site re-development. If previous Phase 1 and 2 ESA have covered the proposed areas by extents and depths, no additional investigation should be conducted. An additional investigation/characterization is only needed if proposed development is beyond the previous investigations.
• In term of detailed sampling requirements, the sampling frequency for both in-site and stockpile approach is too excessive. This shall be based on the Phase 1 and 2 ESA results. For example, a station box deep excavation at Eglinton Crosstown LRT project can be as deep as 25 m below grade. Our approach is to take more samples from shallow soil layers due to historical activities and APECs and less samples from deep layers. If the required sampling frequency is applied, way too many samples will have to be taken from deep layers and the results will be repetitive and excessive.

In a conclusion, Phase 1 and 2 ESA shall be the minimum requirements to determine excess soil characterization. Additional investigation shall be based on specific site development and excess soil volume. Sampling frequency shall be based on Phase 1 and 2 ESA findings.

4) Clean Soil Disposal at a Landfill or Dump

Soil Rules requires that clean soil (meets Table 2.1 for RPI Standards) may not be deposited at a landfill or dump. In some cases, clean soil has to be disposed at a landfill due to being geo-technically unsuitable, or unable to find suitable beneficial reuse receiving sites, or construction schedule, etc. If clean soil is used for landfill cover layer or the volume is limited, this rule shall be more flexible and/or leave the project leader/QP to provide rationale for disposal.
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