Develop remediation strategy: step 7 of federal contaminated sites decision-making framework

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Step 7: develop remediation/risk management (R/RM) strategy

A Remediation/Risk Management (R/RM) strategy is developed once the results of the preliminary (Step 3) and detailed (Step 5) testing have indicated that risks from contamination must be addressed.

Selection of the R/RM strategy is one of the most critical decisions in the 10-step process, since the outcome will largely determine the cost and effectiveness of the chosen approach on the reduction of risk to human health and the environment, and on the reduction of financial liability. The financial liability for the site, based on the risk and the federal government’s obligation to address it, should also be calculated by the end of Step 7.

Careful consideration and evaluation of R/RM objectives, options and regulatory requirements will reduce the possibility of error and substantially increase the affordability and technical effectiveness of the proposed site management strategy. When selecting R/RM methods, consider sustainability and climate change measures. Look for opportunities to demonstrate the feasibility of incorporating sustainable remediation activities. The Preliminary Sustainability Plan (PSP) developed in Step 2 should be updated based on the site management strategy and the expected activities to occur on site during R/RM implementation and execution.

When selecting sustainable R/RM methods, consider risk management (as opposed to remediation) approaches where appropriate land-use restrictions and human health and environmental protection can be assured. Where risk management approaches are not possible, consider the use of in-situ remediation techniques and those that destroy contaminants. Use a qualitative, semi-qualitative [i.e., the Sustainable Development Tool (SDT) (PSPC, 2016), or quantitative (i.e., life-cycle analysis) approach to evaluate the sustainability of viable R/RM options for the site.

At Step 7, it is recommended that custodians begin to fill in the Guidance for Site Closure Tool for Federal Contaminated Sites (SCT) (FCSAP, 2012). It enables custodians to evaluate key decisions and document important information about the R/RM activities leading to the eventual closure or long-term monitoring/management (LTM) of the site.

Step 7 describes two approaches, the Guideline Approach and the Risk Assessment Approach. A description of each of Step 7’s sub activities follows the flow diagram.

Key decision(s):

Step 7: Develop Remediation/Risk Management (R/RM) Strategy
Long description

All activities in Step 7 should consider the future impacts of climate change on the site and should aim to use sustainable approaches. Consider one of two approaches for determining remediation/risk management (R/RM) objectives: the Guideline Approach or the Risk-Assessment Approach.

For the Guideline Approach, choose one of these options: (1): Accept generic environmental quality guidelines (e.g., Canadian Council of Ministers of the Environment [CCME] Tier 1) as remediation objectives; or (2) Modify generic environmental quality guidelines to develop remediation objectives (e.g., CCME Tier 2).

For the Risk-Assessment Approach, conduct a risk assessment. If no risk is identified, record the decision and close the site in the FCSI. If a risk is identified, choose one of these options: (1) Develop risk-based, site-specific target levels as remediation objectives (e.g., CCME Tier 3); or (2) Identify possible risk-management options.

After either the Guideline Approach or Risk Assessment Approach has been selected and options within have been chosen, carry out these steps: define and analyze options for R/RM strategy, taking stakeholder input into consideration; complete R/RM strategy, which includes the Remedial Action Plan / Risk Management Plan (RAP/RMP), integrating the updated Sustainability Plan, and complete appropriate sections of the site closure tool (SCT); update the FCSI and remediation liabilities estimates, then proceed to Step 8.

Step 7.1: Based on the current and intended land use, consider approaches for developing a site management strategy

To develop their site management strategy, custodians will need to identify the R/RM objectives and select the best options for attaining them. These two important decisions will be made in parallel, based on the current or intended federal use of the site, which was first identified at Step 3 and Step 5 but should be reconfirmed.

R/RM objectives may be developed for a site using a guideline approach--where generic or modified guidelines are adopted--or using a risk assessment approach to derive site-specific target levels as remediation objectives. Choosing between the guidelines or risk assessment approach depends on the circumstance. For instance, if the potential site management strategies based on the guideline approach are too costly or are unacceptable for other reasons (e.g., technical feasibility or unacceptable environmental damage caused by the remedy); it may be advantageous to perform a risk assessment. A risk assessment may help custodians to better understand and focus on the main drivers of risk at the site, which can optimize R/RM actions. There are many conditions under which one or both of these approaches may be implemented. Switching between the risk assessment and guideline approach is not prohibited; an iterative analysis of the alternatives is encouraged and works to optimize the final strategy. For both approaches, custodians should take into account the effects of future climate changes on their current site conditions - including media, pathways and receptors.

Step 7.2a: guideline approach option A

Accept generic environmental quality guidelines as remediation objectives

Published guidelines such as the CCME Canadian Environmental Quality Guidelines are selected as the remediation objectives. These are conservative, generic numeric concentrations of residual contamination that are considered to be acceptable for a wide range of site conditions and receptors under defined land uses.

Step 7.2b: guideline approach option B

Modify generic environmental quality guidelines to develop remediation objectives

When site conditions, land use, receptors or exposure pathways differ slightly from those set out for the generic guidelines, and when adjustment of certain parameters in equations or pathway exposure assumptions is deemed acceptable based on jurisdictional approval and guidance, it is possible to apply limited modification of generic guidelines.

Step 7.3: risk assessment approach

Conduct risk assessment

When the environmental quality guideline approaches cannot be implemented, or if site conditions are unique or particularly sensitive and would limit the effectiveness of generic criteria, a risk assessment approach may be used to determine if the existing contamination/site conditions represent a risk. If generic environmental quality guidelines for the contaminant of concern do not exist in Canada or other jurisdictions, if costs of remediating to guideline levels are too high, if the site is particularly large and complex, if the environmental impacts of using available remediation techniques are unacceptable, or if little information is known about the contaminants of concern, risk assessment may be warranted.

Depending on the site and receptors present, both a human health and an ecological risk assessment will likely be necessary. Guidance for these assessments is published by the FCSAP program, the (CCME), Health Canada (HC) and Environment and Climate Change Canada (ECCC). A risk assessment at Step 7 typically requires substantially more effort and detail than simpler risk assessments that may have been completed previously.

A risk assessment can identify R/RM Site Specific Target Levels, but can also reveal that no unacceptable risk exists at this site. When this is the case then no other, no further action is required and the site should be closed in the Federal Contaminated Sites Inventory (FCSI) (Treasury Board Secretariat). No further action should also be recorded in the Site Closure Tool (mandatory for FCSAP-funded sites) (FCSAP, 2012) and the recommended Tool for Risk Assessment Validation (TRAV) (found in the Site Closure Tool). If risks are identified, they can either be managed through remediation to site-specific target levels or by risk management of the contamination in such a way that no risk exists, essentially blocking exposure pathways between the contamination and the receptors of concern.

Step 7.4a: risk-assessment approach option A

Develop risk-based site-specific target levels as remediation objectives

Site-specific target levels (SSTLs) are established using risk assessment. SSTLs are concentrations at or below which no risk exists for this particular site. Remediation should aim to attain those levels.

Step 7.4b: risk-assessment approach option B

Identify possible risk management options

Options for risk management typically involve engineering or institutional controls that a) interrupt the exposure pathways (e.g., installing fencing, filtering drinking water, removing children’s sandboxes, importing clean soil for raised garden beds); b) remove receptors (e.g., not allowing deep-rooted trees on site); or c) change the form of the contaminant to make it less accessible (e.g., liming soil to reduce metal mobilization, encapsulating metals in cement).

Step 7.5: define and analyze options for site management strategy, taking stakeholders’ input into consideration

A site management strategy may include one or a combination of R/RM options to address a variety of site conditions. For example, it may be decided that remediation methods are appropriate for some areas of the site or impacted media, but that other site conditions are more appropriately addressed by engineering and/or institutional controls to prevent potential exposure by receptors. In this context, it is necessary to consider various options and to assess their relative advantages and disadvantages. Custodians should consider future effects of climate change and apply sustainability principles when selecting R/RM methods, and look for opportunities to demonstrate the feasibility of incorporating sustainable remediation methods.

Step 7.6: select site management strategy and develop remediation action plan/risk management plan (RAP/RMP)

Once the preferred R/RM techniques are determined, a strategy is developed that may rely on a combination of R/RM approaches. One of the main components of the strategy is the Remedial Action Plan (RAP) and/or Risk Management Plan (RMP), depending on the chosen route. Each plan should contain some key details about the site, including the following:

Step 7.7: complete appropriate sections of the site closure tool (SCT), including the tool for risk assessment validation (TRAV)

The Site Closure Tool (SCT) (FCSAP, 2012) is meant to provide custodians with consistent evaluation criteria for determining when it is appropriate to close sites remediated using FCSAP funding. It also provides a template for determining which critical information about site remediation decisions should be documented and summarized in a closure report. The TRAV is embedded within the SCT and acts as a quality assurance tool describing the expectations of ECCC, Fisheries and Oceans Canada (DFO), and HC with respect to the proper procedure for conducting risk assessments. The TRAV is not a mandatory tool, but is strongly recommended by the FCSAP Secretariat. Custodians will begin to fill out the sections of the SCT related to R/RM planning and the quality of site assessment data during Step 7. This will ensure that any deficiencies are identified early enough in the R/RM process that they can be corrected, rather than doing so at the end of the site work.

Step 7.8: update federal contaminated sites inventory (FCSI)

The FCSI should be updated to include liability estimates, if the Treasury Board of Canada Secretariat (TBS) liability recognition criteria are met. At this step, custodians should have sufficient information about the site to meet the five mandatory recognition criteria for reporting a liability as defined by the Treasury Board Secretariat of Canada and report the liability for the site using the Federal Contaminated Sites Inventory (FCSI) portal (TBS, 2016). The estimate of a remediation liability includes costs directly attributable to remediation activities required to bring the site up to the current minimum standard for use prior to contamination. See Step 6 for more details.

How Fisheries and Oceans Canada (DFO) expert support can assist

How Environment and Climate Change Canada (ECCC) expert support can assist

How Health Canada (HC) expert support can assist

How Public Services and Procurement Canada (PSPC) expert support can assist

How the FCSAP Secretariat can assist

Supporting documents and tools specific to Step 7

Please also refer to the list of supporting documents and tools useful throughout the 10-step process at the beginning of the document.

Canadian Council of Ministers of the Environment (CCME) Guidance

Federal Contaminated Sites Action Plan (FCSAP) Guidance

Other guidance and tools


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