Federal approach to contaminated sites: steps for addressing a site
- 2.1 Step 1: identify suspect sites
- 2.2 Step 2: historical review
- 2.3 Step 3: initial testing program
- 2.4 Step 4: classify contaminated site using the CCME national classification system
- 2.5 Step 5: detailed testing program
- 2.6 Step 6: reclassify the site using CCME national classification system
- 2.7 Step 7 : develop remediation/risk management strategy
- 2.8 Step 8: implement remediation/risk management strategy
- 2.9 Step 9: confirmatory sampling and final reporting
- 2.10 Step 10: long-term monitoring (optional)
2.1 Step 1: identify suspect sites
The implementation of the Approach requires sound technical expertise and professional judgement. At each step, the necessary site information is gathered to enable effective management decisions to be made. At some sites, however, it may not be necessary to complete all the steps before making a final management decision. For instance, sufficient information relating to a specific step may already be available, or sufficient information may become available after undertaking only a few of the steps. Additionally, some steps may be combined to make the Approach more efficient. In other cases, at sites where complex contamination issues are identified, it may be necessary to undertake certain steps in sequence to obtain the necessary information before effective management decisions are made. It must also be recognized that each site may present a unique set of circumstances; different approaches, techniques and/or prioritizations may be required to characterize and remediate sites on a site-specific basis.
The objective of Step 1 is to identify suspect sites with relation to environmental issues of concern. A process to facilitate identification of suspect sites will ensure that Environmental Site Assessments (ESAs) are undertaken in a cost-effective and timely manner and that resources are applied where the most benefit will be realized. This step also helps establish the scenarios under which further investigations of a site may be warranted due to past or current activities at or near a site. Finally, this step will assist in screening out sites that do not present a potential risk to human health and/or the environment.
For the most part, contaminated sites are typically associated with commercial, industrial and waste disposal activities and are commonly the result of improper chemical storage practices, spills, leaks and waste disposal. Some contaminated or potentially contaminated sites are obvious, such as sanitary landfills, while others may be innocuous, with the potential for hidden underground contamination. For example, an underground storage tank facility may contain one or more tanks which could be leaking.
How do I identify my potential sites?
There are several different avenues by which potentially contaminated sites may be identified. The majority of these avenues are contingent upon previous investigations and/or reports that may have been generated for the site. As a preliminary overview, useful information regarding the site may be obtained from the following sources:
- previous environmental record(s);
- internal environmental programs;
- complaints by citizens;
- off-site impacts;
- similarities to other known contaminated sites;
- visual or olfactory evidence of previous leaks, spills or discharges; and
- the nature of current or past activities at the site or adjacent properties.
The identification of a suspect site is an integral first step of the Approach. The purpose of the preliminary overview is to ensure that a review of the site has been carried out and that areas of environmental concern have been properly considered. From the information gathered so far, it may be decided that:
- There are sufficient environmental data or evidence about the site such that the Historical Review (Step 2), Initial Testing Program (Step 3) and/or Detailed Testing Program (Step 5) are not required. The next task will then be to Classify the Site Using the CCME National Classification System (Step 4); or
- Further investigations are required to identify and characterize the types, concentrations and extent of contamination. It is then necessary to proceed with the next step, the Historical Review (Step 2).
However, there might be instances for which there are sufficient environmental data or evidence to properly identify the site as not being suspect (e.g. properly constructed and decommissioned landfill sites, documented contaminants stored, handled and disposed of according to regulations, buried inert construction wastes, etc.).
Suppose I am not confident with the information I have?
If the review of the site is inconclusive as to whether the site is potentially contaminated, or if the areas of environmental concern are not properly addressed, then a Historical Review (Step 2) should be carried out to obtain the necessary background information.
It is also important to keep in mind that the physical geography of sites may have changed significantly over time, particularly with sites that have a long-term operational history or had a change in land use. Consequently, there may be no visual indications of remnant or historical activities at the site that may have led to contamination. For instance, closed landfills, waste pits or dump sites may have been regraded to green space, to make them more aesthetically pleasing, or to blend them in with the existing site development.
Upon completion of the site identification, you will be able to assess whether you have a suspect site. If the site is suspected of being contaminated, but more historical and current information is required, you need to proceed with a Historical Review (Step 2).
2.2 Step 2: historical review
The objectives of the Historical Review, also known as a Phase 1 Environmental Site Assessment, are to assemble and review all available historical and current information pertaining to the site. The Historical Review activities may be undertaken to:
- identify potential contaminants and environmental concerns at a site;
- identify the need for further investigation, particularly at sites where little existing information is available; and/or
- establish the preliminary site characteristics and develop a program or work plan for subsequent site investigations.
Following the identification of a suspected contaminated site in Step 1, the next step is to identify the necessary background information through the completion of a Historical Review. It may be necessary to conduct a Historical Review even if information documenting the site's environmental conditions already exists, depending upon the nature of that information. Examples of such instances would be:
- A previous environmental investigation was not representative of the entire site conditions.
- Previous site investigations were undertaken without the benefit of a Historical Review.
- An unknown element or uncertainty identified in Step 1 requires further qualification.
What will the Historical Review tell me?
The Historical Review will identify, through an assessment of available existing information, the suspected areas of potential environmental concern and the need for further investigation. Additional investigations may be required if the existing available information is inadequate to evaluate general or site-specific concerns, or if available information suggests that there is an elevated risk of potential contamination.
The Historical Review will help to determine whether contamination exists on the property as well as the potential source, nature and location of the contamination. At this stage of the Historical Review, cursory information is also gathered upon which a conceptual model can be developed later.
What does the Historical Review include?
The Historical Review generally comprises three principal components:
- a literature review;
- a site visit or walk-through; and
- interviews with informed persons.
For more information on conducting a Historical Review, the Canadian Standards Association (CSA) document CAN/CSA Z768 Phase 1 Environmental Site Assessment (CSA, 1994) outlines a standard approach to conducting a Historical Review, or Phase 1 Environmental Site Assessment. In addition, the CCME publication Guidance Document on the Management of Contaminated Sites in Canada (CCME, 1997b) outlines the phased approach to conducting environmental site assessments, including the elements to be addressed in the initial phase of an environmental site assessment.
Where can I get the information I need to do a Historical Review?
1) Literature Review. Historical information pertaining to the site may be obtained from a literature review of a variety of sources including:
- available reports (such as groundwater and geological reports, environmental baseline reports, incident reports and previous site investigation reports);
- aerial photographs;
- insurance maps and reports;
- property title searches;
- federal, provincial and municipal archives;
- regulatory agency records;
- company records;
- topographic and geological maps; and
- site plans and drawings.
The literature review should also include any and all data which may have been gathered for legal, transactional or environmental reasons. If the information is available, it should also provide information on the types of suspected contaminants, where the contamination is likely to be found, and the subsurface conditions of the site. The information gathered is used to plan any further activities at the site.
2) Site Visit. A site visit is primarily a visual inspection of the property. It is used to verify the information gathered during the literature review and identify any undocumented site conditions that may impact on the site investigations. The walk-through will also identify areas of potential environmental concern including: vegetation stress, key ecological receptors, leachate breakout, and contaminant discharge. The site visit essentially brings the historical review up-to-date with respect to the current land use(s).
3) Interview with Informed Persons. Discussions should also be held with key site personnel at both the subject and surrounding lands. An interview is used to corroborate information gathered during the literature review and site visit. It also helps identify any gaps in the scope of the literature review and site visit. For many of the older federal operations, significant historical data may be obtained from former or retired employees who worked at the site. In addition, local residents may be knowledgeable about the site's history and conditions and may also provide valuable information.
Completing the Historical Review will establish the following preliminary characteristics for the site:
- Facility characteristics: a current and a historical description of the site and its facilities, including site infrastructure. This should also include prior site uses and surrounding land uses.
- Contaminant characteristics: identifies contaminants that may be present at the site.
- Physical site characteristics: examines the geology, hydrology and geomorphology using current information.
A generic Statement of Work for conducting a Historical Review is included in Appendix B.
The site's historical information is now assessed with regard to potential contaminants, pathways and receptors. This information will establish whether additional site investigations are required. Where additional investigations are warranted, the preliminary information obtained in the Historical Review will be used to develop a site characterization work plan.
1. CAN/CSA Z768 Phase 1 Environmental Site Assessment (CSA), 1994
2. Guidance Document on the Management of Contaminated Sites in Canada (CCME), 1997b
2.3 Step 3: initial testing program
The objective of the Initial Testing Program, also known as a Phase II Environmental Site Assessment, is to determine the presence or absence of suspected contaminants and to characterize the physical site conditions, including geology, hydrogeology and hydrology. If the results of the Historical Review have identified a potential environmental concern, an Initial Testing Program should be undertaken to qualify and quantify those concerns. Where present, the Initial Testing Program will provide a preliminary assessment of the degree, nature and extent of the contamination. The Initial Testing Program should also provide the necessary level of information to support management decisions regarding future investigation needs and requirements. The more information that is known about the site, the better the site classification and site prioritization with respect to the form of action required to meet remediation/risk management objectives.
An Initial Testing Program, may be undertaken in one or more stages, depending upon site and contaminant characteristics, the specific objectives of the study and the Initial Testing findings.
The Initial Testing Program consists of six principal stages:
- field investigation and sampling;
- sample analyses;
- data interpretation and evaluation;
- risk identification; and
- conceptual model development.
The Canadian Standards Association (CSA) document CAN/CSA Z769 Phase II Environmental Site Assessment (CSA, 1998) outlines a systematic approach to conducting an Initial Testing Program, or Phase II Environmental Site Assessment. Additional information concerning the development and planning of Initial Testing Programs is provided in the CCME documents Guidance Document on the Management of Contaminated Sites in Canada (CCME, 1997b) and Subsurface Assessment Handbook for Contaminated Sites (CCME, 1994).
1) Planning. The first step in undertaking an Initial Testing Program is to develop a suitable work plan. The work plan should be based on the findings and/or uncertainties identified in the Historical Review (Step 2). In developing the work plan, the Initial Testing Program should incorporate the use of technically sound sampling procedures, quality assurance/quality control procedures and laboratory analytical procedures. The importance of collecting a sufficient number of samples cannot be over-emphasized at this point, as collecting enough samples may reduce potential remediation costs.
Information on these procedures and the planning and implementation of Field Testing Programs can be found in the CCME documents Guidance Manual on Sampling, Analysis, and Data Management for Contaminated Sites - Volume 1: Main Report (CCME, 1993a) and Guidance Manual on Sampling, Analysis, and Data Management for Contaminated Sites - Volume II: Analytical Method Summaries (CCME, 1993b).
The Initial Testing Program may be carried out using a combination of (1) non-intrusive and (2) intrusive techniques. (1) Typical non-intrusive techniques used as initial site investigation methodologies include geophysical and soil vapour (gas) surveys. These techniques are used to rapidly identify subsurface contamination that may be in solid, liquid or gas form, thus allowing a more focused intrusive investigation approach. (2) Typical intrusive techniques include a combination of hand augering, test pitting and drilling procedures to retrieve soil and groundwater samples for subsequent field screening and laboratory analyses. Tightness testing of tanks, lines and pumps may be a component of the program and may be performed at storage tank facilities.
2) Field Investigation and Sampling. Once potential "hot spots" have been identified through the Historical Review (Step 2), a sampling program must be designed to obtain more definitive information about the nature and extent of the contamination. The sampling program should clearly establish the appropriate sampling techniques and equipment, sample density, sampling media and analytical parameters. Appropriate sampling protocols and analytical methods must be developed to meet the needs of the investigation.
The Initial Testing Program should include surface and subsurface soil sampling, groundwater sampling and surface water sampling using approved sampling procedures (e.g. CCME). This program usually begins with one or two field-screening methods, which permit a closer identification of suitable locations for test pits, boreholes and groundwater monitors. Subsurface soil samples are routinely collected through the excavation of test pits, the use of hand augers and a portable drill or the drilling of boreholes. Groundwater samples are collected through the installation of monitoring well at strategic borehole locations. Additional sampling, including sediment, plants or aquatic organisms, may be warranted under certain site-specific conditions. Quality assurance/quality control programs should be established at both the field sampling and analytical levels to ensure data integrity and confidence in the data quality. By following the Guidance Manual on Sampling, Analysis, and Data Management for Contaminated Sites (CCME, 1993a), a quality assurance program can be developed specifically for the assessment of individual contaminated sites.
3) Sample Analyses. In the Initial Testing Program, the sample analyses stage should address the range of possible contaminants identified in the Historical Review (Step 2). The analysis stage may become more refined as investigation activities proceed and the types of contaminants to be analyzed are properly identified, or areas of potential environmental concern discarded. Representative samples should be submitted to a Canadian Association of Environmental Analytical Laboratories (CAEAL) or Ministère de l'Environnement (MENV) du Québec accredited and certified laboratory, or an organization offering an equivalent level of accreditation, for quantification of suspected contaminant concentrations.
On-site methods allow samples to be screened for a variety of suspect contaminants in a cost- and time-effective manner. Samples with the highest contaminant concentration identified by the screening method should then be submitted to a laboratory for detailed analyses and confirmation of actual contaminant concentrations. Information from on-site methods is quickly available and can also determine the need for, and best location for, further drilling if required. Soil and water samples collected during the field testing program may be screened using a variety of techniques, as described in section 5.3.1 of the Guidance Document on the Management of Contaminated Sites in Canada (CCME, 1997b).
4) Data Interpretation and Evaluation. The interpretation of the laboratory data includes (1) a comparison between the data quality objectives and the findings presented in the field program, (2) an evaluation of the quality assurance/quality control data with the data presented and (3) an extrapolation of the information presented to a form that will truly represent site conditions. The gathered data must be representative of the contaminated site being investigated.
When a contaminated site has been identified and the Initial Testing Program has provided information on the nature and magnitude of contamination at the site, environmental quality guidelines can be used for the purpose of evaluating:
- the degree of contamination at the site;
- if further site investigations are required; and
- if management actions are necessary.
The environmental quality guidelines are guidelines for soil, water and sediments. Generic groundwater and surface water criteria have been developed for four water use scenarios: freshwater supporting aquatic life, water used for irrigation, livestock watering and human drinking water. Sediments quality guidelines have been developed for a variety of contaminants in freshwater and marine/estuarine sediments. The 1999 CCME Environmental Quality Guidelines provide generic soil remediation criteria for four different land uses: agricultural, residential/parkland, commercial and industrial. The applicable remediation guidelines will vary according to the prescribed land use, whether present or future.
Which guidelines do I use?
Many different soil quality criteria or guidelines are available, which can be confusing for site managers.
- The CCME released interim soil quality criteria in 1991 and recommended soil quality guidelines in 1997. The 1991 criteria are provided for over 50 parameters, whereas the 1997 guidelines were released for 20 parameters. The 1997 CCME Soil Quality Guidelines have been developed to replace the interim values published in 1991 for specific contaminants. Any interim values for contaminants listed in the 1991 guidelines that have not yet been replaced in the 1997 guidelines will remain in effect.
- Since 1997, the word "guidelines" is being used instead of "criteria" for consistency purposes with other media.
- As a general rule, sites under federal custody are excluded from provincial jurisdiction, and consequently the CCME guidelines are recommended for use. However, when no CCME guidelines are available for a parameter, provincial or territorial guidelines can be used.
- The most recent CCME guidelines for a parameter should always be used since they were derived using the latest and most up-to-date scientific information.
- When no CCME soil quality guidelines are available for a parameter, the CCME 1991 interim criteria can still be used.
- In cases where no provincial or territorial guidelines are available, guidelines from international jurisdictions can be used.
In 1999, the CCME integrated all existing environmental quality guidelines and criteria for all media into one document entitled 1999 Canadian Environmental Quality Guidelines. This document contains the most current environmental quality guidelines for water, soil, sediment, tissue and air, including updates and revisions to the existing environmental quality guidelines published to date. The 1999 CCME Environmental Quality Guidelines replace all previous guidelines.
Note: The proposed Canada Wide Standards for Petroleum Hydrocarbons (PHC) in soil will establish environmental quality guidelines for petroleum hydrocarbon contaminated sites. The application of this standard is still being developed. Additional information on the CWS is available on the CCME web site: www.ccme.ca
A site is generally considered contaminated when one or more samples contain contaminant concentrations in excess of the appropriate environmental quality guidelines. Data for these sites should be stored in a departmental reporting or inventory database for sites exceeding environmental quality guidelines. If contaminant concentrations do not exceed the guidelines, no further action is required (i.e. no classification required). There is no need to go any further in the Approach process.
A generic Statement of Work for an Initial Testing Program is included in Appendix C.
5) Identify Risks. The information obtained during the Initial Testing Program will provide valuable site information, including the nature and location of the contaminants with respect to the groundwater table, potential pathways for contaminant migration, the location of nearby sensitive receptors, and the potential for direct human exposure to the contaminants. These elements will allow development of a conceptual model for the site.
Undertaking a qualitative risk assessment as part of the Initial Testing Program establishes the three components of risk - contaminants, potential receptors, and exposure pathways - and focuses the data collection accordingly. Figure 2 shows the relationship of these three components. In cases where the risks associated with certain contaminants on a specific site are not known, further study of the risks to public health, safety or the environment may be required. This additional requirement would be part of the Detailed Testing Program in Step 5.
6) Develop Conceptual Model. The conceptual model is a desk-top approximation of the physical and chemical (contaminant) site conditions. Upon completion of the Initial Testing Program, it is important to have a conceptual site model of the site, which emphasizes the type and magnitude of the subsurface contamination, defines the pathways for contaminant migration and identifies potential receptors. Where additional investigations are likely to be required, the conceptual site model provides the foundation upon which to develop the subsequent stages of the work. It will also assist in indicating what types of information must be collected. Figure 3 is an example of a conceptual site model for the movement of contaminants to a receptor (human) that would be based on the site information gathered up to this step.
The three preliminary site characteristics (contamination, pathways and receptors), when viewed as a whole, constitute a conceptual site model. Both the Historical Review and Initial Testing Program must be thoroughly evaluated and documented to establish the preliminary site characteristics and determine the potential for site contamination. The conceptual model should be established early in the process when addressing a contaminated site. This allows the resources and subsequent efforts to focus on the contaminants of concern as well as the receptors and pathways that are relevant to site remediation/risk management issues. Once the preliminary model is established, subsequent investigation programs and work plans can be developed to refine the model and to address any critical information gaps.
Figure 2 Risk components relationship
The results of the Initial Testing Program will establish whether the site is contaminated. If contamination is present, the Initial Testing will identify the nature and magnitude of the contamination and provide the necessary information to develop future testing programs. Data obtained during the Initial Testing will allow development of a preliminary conceptual site model in relation to the type and extent of the subsurface contamination, the pathways for contaminant migration and potential receptors. It will also provide useful information that can be used for site classification (Step 4).
Figure 3 Example of a Human Health Conceptual Site Model for the Movement of Contaminant(s) Bound to Surface Soils to a Person
- CAN/CSA Z769 Phase II Environmental Site Assessment, Canadian Standards Association, 1998 (CSA)
- Guidance Document on the Management of Contaminated Sites in Canada (CCME), 1997b
- Subsurface Assessment Handbook for Contaminated Sites (CCME), 1994
- Guidance Manual on Sampling, Analysis, and Data Management for Contaminated Sites - Volume 1: Main Report (CCME), 1993
- Guidance Manual on Sampling, Analysis, and Data Management for Contaminated Sites - Volume II: Analytical Method Summaries (CCME), 1993
- Canadian Water Quality Guidelines (CCREM), 1987
- A Protocol for the Derivation of Canadian Sediment Quality Guidelines for the Protection of Aquatic Life (CCME), 1995
- Recommended Canadian Soil Quality Guidelines (CCME), 1997c
- Canadian Soil Quality Guidelines for Copper: Environmental and Human Health (CCME), 1997d
- Canadian Soil Quality Guidelines for Pentachlorophenol: Environmental and Human Health (CCME), 1997e
- Protocol for the Derivation of Canadian Tissue Residue Guidelines for the Protection of Wildlife that Consume Aquatic Biota (CCME), 1997f
- Canadian Environmental Quality Guidelines (CCME), 1999
2.4 Step 4: classify contaminated site using the CCME national classification system
The objective of Step 4 is to classify the contaminated site(s) identified in Steps 1 through 3, using the CCME National Classification System. If more than one contaminated site has been identified, this initial classification will aid in indicating the level of concern due to each site. It will then be possible to establish relative priorities for the upcoming detailed testing program, if required, and the subsequent remediation/risk management strategy. Assigning relative priority enables resources to be directed to areas of greatest concern.
The National Classification System (NCS) for Contaminated Sites was developed by the CCME in 1992 to aid in the evaluation of the level of concern and the development of management priorities for contaminated sites. The NCS provides a well-documented and uniform approach to classifying sites as high, medium or low risk. Once sites have been classified, priorities for action can be assigned to address contaminated sites on a technical basis. The NCS is not a qualitative or quantitative risk assessment, but rather is a tool designed to screen a site with respect to the need for further action (characterization, risk assessment, remediation, risk management, etc.) to protect human health and the environment.
Once a contaminated site has been identified in Steps 1 through 3, the next step is to classify the site using the NCS Detailed Evaluation Form. The NCS Detailed Form provides a "first kick" ranking system so that sites can be prioritized with respect to the level of risk they represent. Following the Initial Testing Program (Step 3), the environmental data and information accumulated so far may be sufficient to undertake classification of the site using the Detailed Evaluation Form. Sites lacking sufficient information, as is the case for most initial environmental investigations, will likely require additional investigations, as described in the following step (Detailed Testing Program), to properly complete the NCS.
The NCS Short Evaluation Form should be used only where sufficient information documenting the site's environmental conditions already exists and serious adverse impacts are known to be occurring. The majority of sites, however, will require completion of the Detailed Form.
Where can I get a copy of the NCS form?
The NCS form is available in electronic format and may be downloaded from the CSMWG home page (www.ec.gc.ca/etad/csmwg/en/index_e.htm). The electronic format serves as a database allowing storage, retrieval and updating of information on numerous sites. A hardcopy is available from the following address:
CCME Documents c/o Manitoba Statutory Publications 200 Vaughan Street Winnipeg, Manitoba R3C 1T5 Web site: www.ccme.ca
How do I complete the Detailed Evaluation Form?
Under the NCS, sites are assigned one of the following classes:
- Class 1: Action Required
- Class 2: Action Likely Required
- Class 3: Action May Be Required
- Class N: Action Not Likely Required
- Class I: Insufficient Information
The Detailed Evaluation Form consists of a series of questions related to three factors:
- Contaminant Characteristics - the relative hazard of contaminants present at a site;
- Exposure Pathways - the route a contaminant may follow (e.g. groundwater, surface water, direct contact and/or air) to a receptor. There are three subcategories: (a) groundwater; (b) surface water; and (c) direct contact; and
- Receptors - living beings or resources that may be exposed to and affected by contamination (e.g. humans, plants, animals, or environmental resources). There are two sub-categories: (a) human and animal; and (b) environment.
Under each of the three factor headings, there are evaluation factors that must be scored individually based on the specific site and contaminant characteristics. In Appendix D of the National Classification System for Contaminated Sites (CCME, 1992), there is a user's guide that presents a rationale for the score, guidelines for data interpretation of the environmental factors and sources of information to be reviewed for each factor. Based on the total score and total estimated score, the site can be classified.
What data are required to complete the Detailed Evaluation Form?
The NCS Detailed Evaluation Form may be applied to sites where sufficient information is documented about the site's environmental conditions. The minimum data requirements are described in National Classification System for Contaminated Sites (CCME, 1992) and include:
- description of site location;
- types of contaminants or materials likely to be present at the site (and/or description of historical activities);
- approximate size of the site and quantity of contaminants;
- approximate depth to water table;
- geologic map or survey information (soil, overburden, and bedrock information);
- annual rainfall data;
- surface cover information;
- proximity to surface water;
- topographic information;
- flood potential of site;
- proximity to drinking water supply;
- uses of adjacent water resources; and
- land use information (on-site and surrounding).
If there is insufficient information to properly classify the site, the Class I designation is used until additional information is obtained to address the gaps. There may also be a requirement to further refine the relative classification of sites within each priority category to come up with firm conclusions about the need and/or scenario for a remedial action. The additional information required will be obtained through Step 5: Detailed Testing Program. The NCS is a screening tool only and has limited application on northern sites and marine environment sites, in particular.
The initial classification (Detailed Evaluation Form) should be completed for each contaminated site to identify those posing immediate risks to human health and/or the environment. Sites will be classified as 1, 2, 3, N or I, which correlate to high, medium or low priority for action. Such sites can then be prioritized for further investigation or remedial actions.
1. National Classification System for Contaminated Sites (CCME), 1992
2.5 Step 5: detailed testing program
The objective of the Detailed Testing Program is to further define the nature of the site contamination and to address outstanding issues with respect to the development of an effective site management strategy.
The specific objectives of the Detailed Testing Program are:
- to target and delineate the boundaries of identified contaminants;
- to define, in greater detail, site conditions required to identify all contaminant pathways, particularly with respect to risk assessment;
- to provide contaminant and other information necessary to finalize remediation guidelines or risk assessment; and
- to provide all other information required to develop a Remediation Plan and input to specifications and tender documents.
These specific objectives will provide useful input in the implementation of (1) Step 6: Reclassify the Site Using CCME National Classification System; and (2) Step 7: Develop Remediation/Risk Management Strategy.
If the results of the Initial Testing Program indicate that significant contamination exists at the site, a Detailed Testing Program may be required. Generally, the Detailed Testing Program (Step 5) will concentrate only on those areas of concern identified by the Initial Testing Program (Step 3) and address issues such as information gaps and data deficiencies.
A Detailed Testing Program may not be required if the Initial Testing Program:
- was adequate to scope a remedial action plan; or
- did not identify contaminants at concentrations that exceed CCME Environmental Quality Guidelines.
In these cases, proceed to Step 7: Develop Remediation/Risk Management Strategy. For example, limited contamination may be identified in the vicinity of an underground storage tank location. In many such cases, these impacts can be addressed during the tank decommissioning stage as part of Step 7, without the need for additional subsurface investigations.
For substances that are not addressed in the 1999 CCME Environmental Quality Guidelines, it may be appropriate to seek advice from Environment Canada or the provincial regulatory authority.
What does the Detailed Testing Program include?
The systematic approach to the Detailed Testing Program (Step 5) is similar to the Initial Testing Program (Step 3) in that the same investigative techniques and protocols are employed. The data collected during the Detailed Testing Program should be sufficiently representative of the site conditions to finalize the conceptual site model and to provide input to the development of an effective risk management and/or remedial strategy.
As in the case of the Initial Testing Program, the scope of work during the detailed investigation stage will likely incorporate a multi-task, multi-phased approach. Specific activities may include:
- additional intrusive investigations to quantify all contaminants and concentrations;
- computer modelling to establish contaminant distributions and/or migration patterns; and
- other activities required to obtain the necessary information to develop a suitable site management/remedial strategy.
The Detailed Testing Program should also build upon data management, quality assurance/quality control programs, and other systems developed for the Initial Testing Program (Step 3).
The sampling and analytical programs will focus on contaminants of concern identified by the Initial Testing Program. While a smaller suite of chemicals may be analyzed, a greater number of samples are usually collected to quantify the extent of contamination.
The CCME publications Subsurface Assessment Handbook for Contaminated Sites (CCME, 1994) and Guidance Document on the Management of Contaminated Sites in Canada (CCME, 1997b) provide further details on developing Detailed Testing Programs.
How much site information do I really need?
There is no "cut and dried" answer to this question. The answer will be specific to the site conditions and issues at hand. During the detailed investigation stage, additional information should be gathered about the soil characteristics, site geology, site hydrogeology, the types and concentrations of contaminants present and the rate of contaminant migration. The investigation should comprise of a sufficient scope of work to fully determine the extent (horizontal and vertical) of soil and/or groundwater contamination.
As a baseline, the level of information gathered in this step should be sufficient to enable final confirmation of the classification of the site as per CCME National Classification System Detailed Evaluation Form (Step 6).
A generic Statement of Work for a Detailed Testing Program (Step 5) is included in Appendix D.
The nature and extent of the site contaminant conditions, including the horizontal and vertical distributions of contaminants, should be thoroughly established. A finalized conceptual site model that emphasizes the type and extent of the subsurface contamination should define the pathways for contaminant migration and identify potential receptors relative to human health and/or the environment. As a result, the nature of a contaminant, its transport mechanism and its impact on human health and/or the environment is combined with site geological, hydrogeological and topographical information to produce a comprehensive model of how contaminants may be disbursed from a source to a receptor. An example is shown in Figure 4.
- Subsurface Assessment Handbook for Contaminated Sites (CCME), 1994
- Guidance Document on the Management of Contaminated Sites in Canada (CCME), 1997b
2.6 Step 6: reclassify the site using CCME national classification system
The objective of Step 6 is to confirm the previous site classification performed in Step 4 or to reclassify a site based on the data obtained in Step 5: Detailed Testing Program. Based on the additional information obtained, the NCS Detailed Evaluation Form that was initially filled out in Step 4 can be finalized.
After completing the Detailed Testing Program (Step 5), the additional information available will help confirm or update the National Classification System score obtained in Step 4. Sites lacking sufficient information, as is the case following most initial environmental investigations, likely require additional investigations as described in the preceding step, Step 5: Detailed Testing Program, to properly complete the NCS.
The output after this step should be a finalized Detailed Evaluation Form and a site classified as 1, 2, 3, I or N, according to the potential risk to human health and/or the environment.
2.7 Step 7: develop remediation/risk management strategy
The objective of Step 7 is to establish remediation/risk management goals and thus develop an environmental site management strategy such that the levels of, or potential exposure to, contaminants is reduced to meet those goals. Information gathered from previous steps is evaluated against the proposed remediation objectives to obtain a remediation level for the site. Integration with other management issues should be considered and an appropriate management strategy should be developed.
Figure 4 Example of a human health conceptual site model
Prior to the development of a Remediation/Risk Management Strategy, it must be determined whether the field results obtained from Step 3 (Initial Testing Program) and Step 5 (Detailed Testing Program) exceed generic 1999 CCME remediation guidelines. If contaminant concentrations at the site do not exceed the established guidelines, no further action may be required. If contaminant concentrations meet or exceed the generic guidelines, the process summarized in Figure 5 may be used to develop (1) a Remediation Strategy and/or (2) a Risk Management Strategy.
A) Remediation Strategy
The process of developing numeric remediation objectives that will protect both human health and the environment necessitates appropriate use of both generic and site-specific information. As shown in Figure 5, there are two approaches to development of remediation objectives for a site:
- the Guideline Approach; and
- the Risk Assessment Approach.
Because contaminated sites can present specific conditions that are not always accounted for in the development of "generic" guidelines, site-level information must be taken into account when applying guidelines at a site. The process of applying environmental quality guidelines at the site level is known as establishing site-specific remediation objectives. In the Guideline Approach, remediation objectives can either be adopted directly from the published guidelines (CCME Method 1 - Generic Guidelines) or be developed from modifications to the guidelines to take into account site-specific conditions (CCME Method 2 - Site-Specific Objectives). The Risk Assessment Approach involves development of remediation objectives through the use of a site-specific human health and/or ecological risk assessment (CCME Method 3 - Human Health/Ecological Risk Assessment).
Figure 5 Stages in the Development of a Remedation/Risk Management Strategy (Step 7)
Risk Assessment. Risk Assessment is described in the Proceedings of the Workshop on the Management of Federal Contaminated Sites (CSMWG, 1997c) as a process that evaluates the likelihood that adverse effects will occur or are occurring as a result of exposure to one or more stressors. Risk Assessment is the scientific and technical activity that makes use of a detailed evaluation of hazard and exposure potential at a particular site in order to recommend a remediation level will meet the goals of the Site Management Strategy.
The CCME publication Guidance Manual for Developing Site-Specific Soil Quality Remediation Objectives for Contaminated Sites in Canada (CCME, 1996b) identifies conditions under which the various methods described above may be utilized and provides guidance on the implementation of the methods. Generally speaking, the Guideline Approach requires fewer resources while providing a scientifically defensible basis for protection that is sufficiently flexible to account for certain site-specific factors. The Risk Assessment Approach can be more complex and more costly, and is generally utilized when a guideline-based approach is not suitable for a site.
Do CCME guidelines exist for the contaminant of concern present at the site?
If the answer to the above question is "yes," the CCME generic guidelines may be adopted directly as the site-specific remediation objectives (CCME Method 1). However, if the answer is "no," adopting guidelines from other jurisdictions is another course of action. If no other guidelines or options are available, in all likelihood a risk assessment will have to be performed to develop site-specific remediation objectives.
2.7.1 The guideline approach (CCME method 1 and CCME method 2)
CCME Method 1. Guidelines establish conservative, generic numerical concentrations of a contaminant that are considered to be safe (non-toxic) for a broad range of receptors, conditions and regions under defined land uses. Objectives are numerical concentrations selected or derived to define acceptable levels of residual contamination at a specific site. They provide an effective basis for protecting and restoring land and water uses at contaminated sites and are generally viewed by financial institutions as providing the lowest level of risk.
Once the environmental data and evidence for the site are sufficient, following the Initial or Detailed Testing Programs (Steps 3 or 5), it is necessary to assess the degree of contamination at the site. Adopting the generic CCME soil and groundwater remediation guidelines for the relevant land use is the primary approach recommended. The guidelines used for soil and groundwater are the 1999 CCME Canadian Environmental Quality Guidelines. If there are no CCME guidelines available, guidelines from other jurisdictions may be adopted.
The following questions need to be answered in order to adopt the generic quality guidelines:
- What are the contaminants?
- What is the current and intended land use?
- What type of media is affected (e.g. soil, groundwater, etc.)?
- Is the groundwater being used for drinking water or agricultural purposes?
- Are the assumed exposure scenarios and receptors significantly different from those defined by the CCME?
CCME Method 2. Adoption of remediation objectives from modified guidelines may be utilized in situations where site conditions, land use, receptors or exposure pathways differ only slightly from the protocols used in the development of the CCME Recommended Canadian Soil Quality Guidelines (CCME, 1997c). Due consideration should be given to the following factors:
- natural background levels of priority substances;
- possible movement of contaminants in soil to groundwater, air or dust;
- relevance of the toxicological data that were used to derive the generic guidelines to the site under consideration; and
- land uses and receptors of concern under those land uses.
The circumstances under which the soil quality guidelines can be modified and the methods of modification are explained in the CCME Guidance Manual for Developing Site-Specific Soil Quality Remediation Objectives for Contaminated Sites in Canada (CCME, 1996b). This method should be considered first in the establishment of site-specific remediation objectives before planning the use of CCME Method 3: Human Health/Ecological Risk Assessment.
2.7.2 The risk assessment approach (CCME method 3)
CCME Method 3. When site conditions are unique or particularly sensitive, performing a risk assessment forms the basis for developing site-specific remediation objectives. A risk assessment approach may be utilized when the generic guidelines or modified guidelines under CCME Method 2 are not suitable for a site and/or guidelines from other jurisdictions are not available. Other factors of concern that may justify the use of a risk assessment method are:
- it is a large site;
- little information is available about the contaminants of concern;
- land/water use categories may not accurately reflect the exposure pathways at the site;
- sensitive species or habitats are present; and
- costs of remediation to guidelines may be too high.
To determine if risk assessment is appropriate, answer the following questions. If the answer to any of the questions is "yes," a risk assessment may be needed.
- Do you have critical or sensitive habitats (e.g. wetlands)?
- Do you have any transport media for the contaminants (e.g. drinking water supply)?
- Do you have any rare, threatened or endangered species or ecosystems?
- Is the existing or intended land use a natural park or nature preserve?
- Are there one or more chemicals present about which little is known in relation to behaviour and toxicity?
- Are there any unusual site conditions, such as fractured or karstic bedrock or permafrost, lending uncertainty as to the fate of the contaminants?
- Is the nature or thickness of the soil/overburden cover at the site amenable to leaching of contaminants into the bedrock?
- Is there an absence of environmental quality guidelines for the chemicals of concern?
- Are there unusual soil pH conditions (<5 or >9) that may lead to increased mobility of some contaminants?
- Is the cost of remediation to meet remediation objectives established from generic or modified guidelines too high?
- Are there any exposure pathways of the contaminants in the ecosystem that are not considered by the generic guidelines scenarios or that are not understood?
- Will there be a change in the intended land use?
If the following additional site characteristics have not already been identified in Steps 2, 3 or 5, the appropriate action should be taken to collect this information:
- groundwater presence and usage;
- age of people frequenting the site;
- presence of sensitive habitats;
- species of biota that frequent the site;
- land usage of the site - agricultural or residential;
- surrounding land use; and
- presence of basements.
There are two basic types of risk assessment: (1) Human Health Risk Assessment and (2) Ecological Risk Assessment. One or both of these may be required in the development of site-specific remediation objectives. To ensure the protection of both humans (Human Health) and the environment (Ecological), the two types of assessments are required as advocated by the CCME. In situations where both types of risk assessment are used, the lowest site-specific remediation objectives resulting from the assessment process should be selected for the purposes of site remediation.
If a Risk Assessment Approach has been chosen, it is likely that you will have to hire a qualified consultant with the necessary technical and scientific expertise to perform the work. The risk assessment will have to be conducted in accordance with the CCME protocols for ecological risk assessment and human health risk assessment. These include A Protocol for the Derivation of Environmental and Human Health Soil Quality Guidelines (CCME, 1996a) and A Protocol for the Derivation of Water Quality Guidelines for the Protection of Aquatic Life (CCME, 1991c).
For more information on ecological risk assessment as the basis for developing site-specific remediation objectives, consult the CCME document A Framework for Ecological Risk Assessment: General Guidance (CCME, 1996c) and A Framework for Ecological Risk Assessment: Technical Appendices (CCME, 1997a).
A generic Statement of Work for a Quantitative Human Health/Ecological Risk Assessment is included in Appendix C. This Statement of Work will have to be adapted to properly cover the specific aspects encountered at the site.
B) Risk Management Strategy
While the Remediation Strategy developed in Step 7 constitutes the scientific approach towards a site management strategy, it needs to be complemented with a risk management aspect to make the overall site management effective. While the Remediation Strategy (using CCME Methods 1, 2 or 3) will establish which clean-up objectives are most appropriate, the Risk Management Strategy will determine if remedial action is required at a contaminated site. If so, an appropriate remedy will be selected. "Appropriateness" is influenced not only by the degree to which a remedial action reduces risk, but also by the degree that the action meets technical, economic, social and political needs specific to the contaminated site and potentially affected stakeholders.
Risk Management. Risk Management (RM) is the decision-making process in which an action or a policy is developed once a remediation level has been determined. It integrates the Remediation Strategy with technical, political, legal, social and economic considerations to develop risk reduction and prevention strategies. It is the active process of reducing risk associated with a contaminated site to "acceptable" levels or objectives. These acceptable levels are usually defined by regulators in conjunction with site managers, owners and other stakeholders. Generally RM involves a combination of one or more of the following:
- contaminant removal or reduction;
- modifying or limiting use by receptors; and
- interception or removal of exposure pathways.
This ensures that risks to human health and/or the environment are minimized through the effective management of one or more of the three risk components (contaminants, receptors and exposure pathways).
Some of the initial considerations in the establishment of an RM Strategy are:
- departmental mandates and policies;
- solicitation of public and stakeholder input;
- setting protection goals based on land and water use;
- identifying resources and logistics restrictions; and
- outputs from Steps 1 through 6.
The input from decision makers, technical consultants, regulators and other stakeholders is important in the development of an RM Strategy, particularly as it pertains to:
- regulatory permits and approvals;
- public or stakeholder perception and acceptability;
- direct impacts and risks to public and/or worker health and safety;
- direct impacts on the environment;
- risks to the environment;
- other socio-economic impacts (noise, traffic, etc.);
- costs associated with remedial alternatives;
- long-term liability;
- impacts on the value of land or the flexibility of future development options; and
- impacts on or disruption of future operations.
Once the initial management considerations have established the need for remediation and identified the specific problem(s) at the site, a clear statement of the problem requiring further action should be formulated and the goals for site management identified. It is critical that goals be established for the remediation of the contaminated site. The effectiveness of RM decisions can be judged only when the results of these decisions are compared to the goals established for the site.
The remediation objectives for a site need to be established in conjunction with the RM objectives in order to meet site management goals for the current or intended beneficial land use of the site. It may be that at some point there will be no requirement to remediate a site, but simply to monitor it, as part of the RM Strategy. In a property transfer scenario, remediation to intended land use requirements is usually negotiated with the new land purchaser.
C) Cost-Benefit Analysis
Cost-benefit analysis and risk assessment are important components of Remedial Action Plans. A cost-benefit analysis will help to determine the optimum remediation/risk management strategy. In addition, where there are a large number of sites, a cost-benefit analysis will assist in prioritizing the sites for remediation. Primary consideration in prioritizing sites should be given to their NCS score and risk to human health and environment. In cases where human health or a sensitive environment is affected, the cost-benefit analysis would be used to compare options, not to justify action. Risk assessment is important in cases where human health or a sensitive environment is affected, as described for CCME Method 3 (Risk Assessment Approach).
The following questions establish the framework for any cost-benefit analysis:
- What events, activities or aspects will change as a result of the action?
- What is the estimated value of the environmental and human health benefits that will come about as a result of the action?
- What are the estimated costs associated with and created by the action?
- Given the estimated benefits and costs, is remedial action justified?
Notwithstanding the answers to these questions, the decision-making process might also be driven by difficulties in properly quantifying some of the factors as well as defining the qualitative aspects (i.e. when dealing with sensitive receptors or wetlands).
A Remediation/Risk Management Strategy is developed for the contaminated site to meet established remediation goals. Both strategies will ensure that the remediation goals are attained more effectively, efficiently and economically.
- Proceedings of the Workshop on the Management of Federal Contaminated Sites (CSMWG), 1997
- Guidance Manual for Developing Site-Specific Soil Quality Remediation Objectives for Contaminated Sites in Canada (CCME), 1996b
- Recommended Canadian Soil Quality Guidelines (CCME), 1997c
- Canadian Water Quality Guidelines (CCREM), 1987
- A Protocol for the Derivation of Environmental and Human Health Soil Quality Guidelines (CCME), 1996a
- A Protocol for the Derivation of Water Quality Guidelines for the Protection of Aquatic Life (CCME), 1991
- A Framework for Ecological Risk Assessment: General Guidance (CCME), 1996c
- A Framework for Ecological Risk Assessment: Technical Appendices (CCME), 1997a
2.8 Step 8: implement remediation/risk management strategy
The objective of Step 8 is to implement the Remediation/Risk Management Strategy developed in Step 7. This step includes the following items, which should be examined prior to selection of a technology:
- evaluating applicable technologies, including the use of treatability studies where appropriate. These studies are performed where there is a need to confirm the effectiveness of a particular technology under specific site conditions;
- conducting a cost-benefit analysis;
- preparing a remedial action plan, including a worker health and safety plan and tender documents;
- selecting a contractor; and
- maintaining proper documentation, quality control, and communication with stakeholders during implementation of the remedial action plan.
Which of the preceding items need to be addressed will be dictated by the Site Management Strategy developed as a result of Step 7.
Following the site investigation, it is necessary to determine the remedial options. This step is an essential part of the decision-making process and provides the justification for any action or inaction and comparison of remedial alternatives. The CCME Guidance Document on the Management of Contaminated Sites in Canada, Section 7 (CCME, 1997b) outlines a process for the preparation and implementation of risk management or clean-up plans. Depending on the operational history of the specific site and the complexity of contamination problems, remediation can range from being a straightforward and simple clean-up to a complex, expensive project over an extended period of time. Comprehensive evaluation of alternatives, careful planning of remediation, and controlled yet adaptable implementation will facilitate effective, efficient and economical restoration of a contaminated site.
How do I identify and evaluate remedial technologies?
There are a few general remediation/risk management approaches that can be used to achieve the remediation objectives set in the Remediation/Risk Management Strategy (Step 7). The three main remedial approaches are:
- removal and disposal;
- containment or encapsulation; and
The principal methods of achieving any of the above remedial approaches are:
- in situ - contaminated material, such as soil and groundwater, is remediated in place on the site without removal;
- ex situ - contaminated material is removed by excavation or pumping, remediated on site and then replaced; or
- off-site - contaminated material is removed by excavation or pumping and transported off site to a licensed facility, for either remediation or disposal.
Any combination of the above may form the Remediation Strategy. The Remediation Strategy selected for a site should be a practical and safe approach to addressing the contaminants of concern. It should be cost effective and should mitigate environmental and health effects. Priority should be given to those technologies which have the potential of minimizing environmental impacts during implementation (construction, digging, hauling, etc.). Site Remediation Technologies: A Reference Manual (CSMWG, 1997d) is a good summary of various remediation technologies.
The following questions should be answered to evaluate the remedial technologies for your specific site and contamination matrix:
- What media are affected by the contamination present (e.g. soil, groundwater, surface water, debris, structures, etc.)?
- What is the contaminant type (e.g. inorganic, volatile organics, semi-volatile organics, radioactive materials, etc.)?
- What are the geological, hydrogeological, hydrological, ecological and climatic site-specific characteristics?
- Are there particular site restrictions due to the proximity of buildings, residential neighbourhoods, schools or sensitive receptors or wildlife habitat?
- What are the regulations regarding the substances of concern?
Research on various remedial technologies may be required to assess the effectiveness of the methods proposed for contaminant removal. It is advisable to carry out a literature review to determine the available technologies and their applicability to your site. Environment Canada has many publications that contain technical summary reports on various remediation technologies. Technical summaries are also available on-line from a variety of organizations and agencies including the Ground-Water Remediation Technologies Analysis Center (www.gwrtac.org); Remedial Technologies Network (www.remedial.com); U.S. Environmental Protection Agency Technology Innovation Office (www.clu-in.org); and the Ontario Centre for Environmental Technology Advancement (www.oceta.on.ca).
As there are hundreds of remediation technologies, selection is a demanding process. But keeping in mind the chosen remediation approach and site-specific conditions will narrow the list to a few acceptable alternatives.
Treatability studies, such as a bench scale test or pilot scale test, can be used to evaluate the performance and cost effectiveness of a particular technology on a given contamination matrix.
What should be included in the Remedial Action Plan?
The Remedial Action Plan should:
- summarize all data from previous site investigations;
- identify contaminants of concern;
- identify the media affected;
- identify, quantify and characterize the materials to be treated or removed;
- if required, summarize the remedial options evaluated and describe the methodology used to select the preferred strategy;
- describe in detail the process of remediation using the selected technology;
- detail an implementation plan including schedule and associated costs;
- identify control measures to minimize air emissions, control surface water, and minimize the risk to worker health and safety;
- detail a contingency plan in the event that contaminants are released into the environment;
- identify the fate of residual contaminants; and
- describe remedial verification and long-term monitoring plans.
Who should provide input to the Remedial Action Plan?
Depending upon the complexity and size of the project, you may want to conduct an independent technical review of the Remedial Action Plan, as well as solicit input from the public and stakeholders, such as public interest groups, through a public consultation process or public meetings. You may also want to consult regulatory agencies to determine the need for an environmental assessment in accordance with the Canadian Environmental Assessment Act (CEAA) prior to executing the plan, as well as identify regulatory requirements during implementation. In cases involving the partial remediation of a site or implementation of a strategy, regulatory agencies such as Environment Canada and Health Canada should be consulted prior to commencing the work to verify if the approach is acceptable from a regulatory perspective. If not, other alternatives should be examined.
What is included in the selection of a suitable contractor?
Preparing detailed specifications and tender documents and selecting a knowledgeable, experienced contractor is imperative to successful remediation activities. Both the primary contractor and subcontractors must be able to demonstrate previous successful experience using the recommended remediation technology in similar site conditions. A proper health and safety plan should also be developed for the site.
The specification and tender documents should contain the following:
- concise descriptions and specifications that outline each component of the implementation plan if not in the contractor's proposal;
- a clear statement of the Remedial Action Plan objectives;
- pertinent information regarding the site, including geology, hydrogeology, hydrology, surrounding land uses and contaminant distribution; and
- a request for unit rates for additional works that may be encountered but are unforeseen.
In addition, the bidders should be able to visit and walk through the site and have the opportunity to ask questions to the existing or previous site managers and users.
Proposals developed in response to the tender should include:
- a concise description that outlines each component of the implementation plan;
- a detailed work schedule;
- identification of the need for feasibility studies;
- bench scale tests;
- a site monitoring plan;
- a health and safety plan;
- a quality assurance program;
- a reporting schedule (i.e., progress or status reports from the contractor); and
- a contingency plan.
How do I maintain control during implementation?
During the course of conducting remediation, it is critical to establish and maintain an organized, comprehensive record-keeping and documentation system as part of an overall quality assurance program. Reporting and documentation requirements as well as the chain of responsibilities should be clearly defined in tender and contract documents. Quality assurance activities may be executed by knowledgeable site personnel or a consultant.
Access to a contaminated site should be controlled during the site investigation and remediation. The site control methods used (e.g. fencing, posting of signs regarding restricted access, etc.) will depend on the scale of the project, land use, proximity to neighbouring properties, and site accessibility. Controlling access to the site will help minimize the exposure of workers, protect the public from site hazards, and prevent vandalism.
How should changes in the Remedial Action Plan be addressed?
During remediation, unanticipated developments frequently occur. Therefore, a Remedial Action Plan must be adaptable enough to respond to new site information. The specification and tender documents should include provisions to address these changes.
Changes to a Remedial Action Plan may require:
- increased or reduced treatment system capacity;
- personal protective equipment; and
- monitoring activities.
Depending on the nature of the project and the scope of the changes to the plan, stakeholder consultation or communication may be necessary.
A definitive Remedial Action Plan that addresses the Remediation/RM Strategy objectives is established and implemented for the site.
- Guidance Document on the Management of Contaminated Sites in Canada (CCME), 1997b
- Site Remediation Technologies: A Reference Manual (CSMWG), 1997
2.9 Step 9: confirmatory sampling and final reporting
The objective of the Confirmatory Sampling and Final Reporting is to ensure that remedial objectives are met following the implementation of a Remedial Action Plan. In addition, the site conditions will be documented in a report for future reference.
For sites that have been remediated or subjected to risk management, the confirmatory sampling is completed to demonstrate that the contamination has been removed or stabilized effectively and that the clean-up objectives have been attained. A final report documents all activities carried out during site decommissioning and clean-up, and includes drawings, records, and monitoring data (relevant in program and confirmatory data).
What are the steps involved in confirmatory sampling?
The following items are included in the confirmatory sampling of a remediated site:
- A sampling of contaminated media (soil and/or groundwater) is conducted to ensure that remediation or risk management objectives have been achieved.
- Sample results are compared with remediation objectives.
- If confirmatory sampling results indicate that remediation objectives were not attained, further remediation may be necessary.
- A final report is prepared to present data collected throughout the remedial process, including a record of sampling events.
- Reports and documents should be retained in perpetuity or until such time as the property is transferred from the federal government portfolio.
The completion of remedial activities and the adequacy of remediation technology is validated by confirmatory sampling. If sample results indicate that the clean-up objectives were not attained, further remediation is required or a change in the remediation technology may be necessary.
Who should conduct confirmatory sampling?
Sampling should be completed by a third party qualified to carry out such work, using standardized and consistent sampling methods. Personnel qualifications should be outlined in a confirmatory sampling plan. The contractor is responsible for covering the costs of the confirmatory sampling to demonstrate that (1) the technology used is adequate and (2) the deliverables (remediation objectives) are met.
Where should samples be analyzed?
Samples should be analyzed by a laboratory with an appropriate quality assurance/quality control (QA/QC) program and accreditation from the Canadian Association of Environmental Analytical Laboratories (CAEAL), the Ministère de l'Environnement (MENV) du Québec or an organization offering an equivalent level of accreditation. Ensure that consistent analytical methodologies are used, and avoid changing laboratories during the remediation process, if possible. Appropriate numbers of duplicate and blank sample analyses should be undertaken as well.
Following the confirmatory sampling program, a final report recording sampling results and confirming that remediation/RM objectives were met will be produced. Alternatively, the report may state that there are levels of contamination above those addressed by the remediation objectives and that further remediation is required. Land use restrictions will be documented if the remediation objectives cannot be achieved, or a risk assessment may be performed to demonstrate that residual levels of contamination are acceptable.
2.10 Step 10: long-term monitoring (optional)
The objective of Long-Term Monitoring is to confirm that the nature and extent of the remediation activities have been carried out as per the site management goals.
Is long-term monitoring required at my site?
It may not always be possible to clean up a site to a level that results in removal of all significant concentrations of contaminants. This may lead to short- and long-term restrictions on intended land use for the site. The feasibility of clean-up may be limited as a result of:
- limitations in technology;
- accepted operating practices of the industry; and/or
- the nature of the contamination.
Depending on the nature and extent of remedial activities on the site, long-term monitoring may or may not be required. Each site must be evaluated according to potential risks for off-site migration and ongoing impact. Long-term monitoring is always required in cases where remediation activities utilized containment, in situ or isolation techniques. Generally speaking, long-term monitoring is an integral part of a Risk Management Strategy and allows the implementation of any contingency plan previously developed for the site.
How do I develop a long-term monitoring program?
If a long-term monitoring program is required, the following questions should aid in its design and implementation.
- What are the key parameters that should be measured? These should be indicative of contamination or of migration of contamination and/or have significant impact on the ecosystem.
- Which sampling locations are indicative of containment status and mobility?
- Are these sampling locations going to be accessible during the sampling period?
- Are there particular, site-specific conditions that may affect contaminant migration, which should also be monitored (e.g. groundwater table elevation)?
- Do current or future land uses on or near the site have the potential to affect the ecosystem? If yes, what are the respective indicator contaminants?
- What is the rate of contaminant mobility and how is this rate affected by the time of year?
- What is the appropriate monitoring duration, based on the rate of contaminant mobility and the potentially affected land uses?
- Is it appropriate for the receptors that were identified in the ecological risk assessment to be sampled for indicator contaminants? If so, their life cycle and migration patterns should be considered.
- What monetary and personnel resources are available to conduct the long-term monitoring?
Monitoring programs must be developed on a site-specific basis, be periodic, and be conducted by qualified individuals. The long-term monitoring program may consist of:
- inspection of on-site containment and treatment facilities;
- groundwater, surface water and atmospheric sampling and analyses;
- inspection of stabilized structures; and
- inspection of restricted site access measures.
How do I interpret the results?
The long-term monitoring results must be evaluated against the site-specific remediation objectives developed in Step 7. In addition to comparing the long-term monitoring results with the remediation objectives, contaminant trends should be identified. A steady increase of a contaminant or an indicator over time could be indicative of contaminant migration or of additional contamination due to on-site or nearby activities. As well, site-specific conditions should be documented during sampling periods, and any possible effects of these conditions on contaminant migration should be noted.
To determine if the results of the long-term monitoring program are satisfactory or if follow-up measures are required, ask the following questions:
- Are there exceedances of the remediation objectives?
- Is there a general trend of increasing contamination concentration over time?
- Have site-specific conditions varied, which could increase contaminant migration?
- Has site redevelopment created an additional receptor or exposure pathway that must be considered?
If the answer to any of the above questions is "yes," additional investigation, as outlined below, may be required.
What if the Risk Management Strategy needs to be modified?
If monitoring results indicate exceedance of remediation objectives, suitable action would include reporting the exceedances to the appropriate level of management, and re-evaluating the Remedial Action Plan so that the necessary contingency measures can be taken. There may also be a need to consider once again a remediation program through a re-evaluation of the Risk Management Strategy. If the results of the re-evaluation are not adequate, it may be necessary to go back to Step 7: Develop Remediation/Risk Management Strategy or Step 8: Implement Remediation/Risk Management Strategy.
An optional long-term monitoring program will assess the effectiveness of a Remedial Action Plan identified as part of the Risk Management Strategy for the site.
Report a problem or mistake on this page
- Date modified: