Risk assessment practitioners and risk managers recognize the need for a clearer decision-making process with respect to the management and remediation of contaminated sites. This presentation will introduce a decision-making tool for interpreting the acceptability of risks in ecological risk assessment (ERA). In contrast to human health risk assessment (HHRA), there are no clear, functional criteria established in Federal or Provincial regulation to determine the acceptability of potential risks and associated uncertainties to ecological receptors. A flow chart and supporting narratives were developed to guide decisions about risk acceptability and harmonize decision-making for ERAs submitted under the British Columbia Contaminated Sites Regulations. This work was supported by the Society of Contaminated Sites Approved Professional (CSAP) of British Columbia. The target audience for this presentation includes risk assessment practitioners and project managers/decision-makers. The potential for elements of this approach to be applied to Federal sites will be discussed.

Throughout Canada, soil and groundwater contamination is often managed by establishing on-site clean-up targets through a risk assessment. The established process relies on analytical models facilitated through standardized risk assessment tools (MRGA, SST, etc.) to estimate the mass that can be left on-site and result in acceptable risk. This approach is designed to be conservative, but can in many cases be unreasonably conservative and in conflict with the concepts of sustainable remediation. Furthermore, this approach does not directly account for the uncertainty that is inherently present when assessing subsurface conditions. Such uncertainty stems from having: 1) incomplete understanding of the hydrogeology and groundwater flow system; 2) incomplete characterization of the contaminant source/distribution in the subsurface; and, 3) incomplete measurements of hydrogeologic parameters.

Numerical modelling that includes uncertainty assessment provides a more scientifically-rigorous approach that more accurately reflects site-specific conditions and the implications of hydrogeologic uncertainty. As such, this approach provides better science-based information for decision-makers, which enhances transparency and provides additional confidence when determining appropriate risk management measures for sustainable remediation. Developments in cloud computing and numerical analysis tools have made meaningful assessment of model prediction uncertainty more cost-effective and informative. With such advancements, detailed models that utilize detailed site data and accurately depict our understanding of the hydrogeologic setting can be readily applied. The uncertainty analysis provides insights regarding the range of potential exposure levels, the most likely levels, the timing of expected exposures, and key data gaps that control the level of uncertainty. 

Project stakeholders, including regulators, will find uncertainty analysis to be an especially valuable tool because it provides a high degree of confidence for human health and ecological risk assessment. This presentation will illustrate how modelling tools are being applied to evaluate contaminant prediction uncertainty, and evaluate remediation alternatives for selected sites while creating simple communication tools to engage different stakeholders in the decision process. 

The former Britannia Mine operated near Vancouver, Canada from 1904 to 1974 and at its peak was the largest copper producer in the British Commonwealth. During its 70-year operation the Mine generated more than 40 million tonnes of tailings, a large proportion of which were deposited in the adjacent marine waters of Howe Sound and used as fill along the Britannia Beach shoreline. The acid-generating tailings and former mine workings leached dissolved copper and zinc into Britannia Creek (which drains to Howe Sound) as well as directly into the ocean until the late 1990s when the provincial government began various ambitious reclamation works intended to intercept, collect and treat water-borne metals discharging to the environment. Studies conducted prior to the initiation of these works indicated that marine water in Howe Sound was lethal to caged salmon and, presumably, to wild juvenile salmon migrating past the outlet of Britannia Creek and that the intertidal community, within one kilometre from the Creek mouth, was depauperate of species typically found at unaffected sites in Howe Sound.

An overall remediation plan (ORP) was developed in 2003 with general remedial objectives of reducing the discharge of potentially harmful substances to allow shoreline habitat areas and aquatic communities to naturally recover and to facilitate the implementation of remediation in a cost-effective and timely manner such that major environmental risks are reduced or controlled as soon as possible. It was also contemplated in the ORP that later remedial efforts at the site would be guided by an ecological risk assessment process.

Through a process of continuous improvement, the remedial activities identified in the ORP have been met and the discharge of dissolved metals has been controlled such that the lethal conditions in Howe Sound no longer exist and intertidal organisms are recovering along much of the shoreline near Britannia Beach. However, as the remediation project evolved from late 2003, it became evident that a standard whole-site risk assessment approach to identifying environmental remediation “success” at the site was likely an over-simplification and a subsequent risk assessment plan (RAP) was proposed with the objective of demonstrating, at an overview level, a proposed approach to a future risk assessment for the remediation program. An overall closure plan (OCP) framework was subsequently developed in 2010 to outline a decision-making process that would be followed to achieve “closure” of the site, defined as the desired long-term “care and maintenance” status for the site. 

An important component of completing work in remote Canadian communities is the engagement and involvement of local or regional Aboriginal groups. The benefits of this are two-fold, firstly, the benefit to the community as a whole, and the benefit to individual members can provide for long-term positive changes in the region; and, secondly, the benefits to a project can include positive cost, schedule and logistical elements. For many projects, it is likely that the owner has already completed some form of stakeholder engagement during the design and planning phase, but as the contractor or construction manager, it is important to continue this engagement while carrying out the work to prevent the Aboriginal stakeholder involvement from being minimized. There two main streams of engagement that should be considered while preparing to complete a project in a remote community, employment and procurement.

Employment of members of the local or regional Aboriginal groups has many benefits including boosting employment rates and economic factors within the community as well as providing future opportunities for individual members through the training and experience they may receive during the project. Examples of employment engagement may include: meeting with regional officials to evaluate labour resources; holding job fairs or meet and greets to introduce the project and opportunities available; engaging in active recruiting methods; and, the provision of training programs that can be taken used to help secure future employment opportunities, once the project is complete.

The second stream of engagement, procurement, can also bring significant benefits to the community and local Aboriginal businesses. These businesses often hold valuable knowledge and resources that can greatly increase the odds of the project’s success. Aboriginal business can be considered within the project for subcontracting services for completing portions of the work, supplier services for providing essential job materials and supplies and for unique partnership opportunities.

Using specific examples from each of these two engagement streams, this presentation will explore some of the unique ways we have been able to increase Aboriginal stakeholder involvement on our projects, as well as some of the challenges that have been faced.