The Middle Harbour Fill Site (the site) remediation project was anticipated to be a difficult project due to the location, the complexity of the contamination on-site, and the presence of many stakeholders with competing interests. Careful planning and consultation resulted in the successful execution of this project as well as satisfied stakeholders. This case study demonstrates how these outcomes were achieved.

The site is a Transport Canada owned property that was created through the infilling of a portion of Victoria Harbour during the industrial operation of a historical paint factory from 1922 to 1972. Historical contamination included hazardous waste concentrations of PCBs, petroleum hydrocarbons and leachable metals. The site is located on Laurel Point which protrudes from the south shore of the Victoria Harbour in downtown Victoria, BC and has no direct road access. The site is located adjacent to an active harbour and vibrant downtown community which includes many stakeholders. Immediately bordering the site is a hotel, two residential condo buildings, a City of Victoria owned park, a float plane taxiway and a Transport Canada Harbour Patrol controlled boat traffic lane used by the Coho ferry and private boaters. The site itself was also used as park space by the general public since 1978 when the paint factory was demolished. Remediating the site was challenging due to its location (proximity to an active seaplane taxi way and Victoria Harbour) as well as the complexities due to the depth and distribution of contaminants which consisted of 75,000 tonnes of material up to seven metres below ground surface.

The spatial organization of contaminant classes was challenging due to the heterogeneous nature of the infilled material. Over 18 years of investigation data was compiled and georeferenced to create a dataset that classified contaminant classes into manageable units. A preconstruction topographic survey was used as the remediation baseline to determine spatial orientations, contaminant depths, excavation extent and material volumes. The designed final grade for the future park was digitized and included in the remediation specifications. The digitized final grade was used to predetermine the depths of confirmatory samples from a risk exposure perspective and to make real time decisions in the field. Risk-based site-specific remediation targets (SSRTs) were developed for the site and included as a remediation objective to determine excavation extents. Since risk-based targets are depth dependent spatial comparison of confirmatory samples locations to the final grade surface in real time was necessary to determine remedial extents.

Stakeholder management was a key component to the success of the project. Discussion and planning included representatives from Transport Canada, Public Services and Procurement Canada, the City of Victoria, the remediation contractor, the remediation consultant, the environmental monitoring consultant, the hotel, neighbouring condo boards, community groups, the Harbour Master, The Coho ferry, Nav Canada, local First Nations and the public. Site access was very limited and therefore barge ramps were constructed to facilitate the transportation of material via barge to treatment facilities and landfills, thereby eliminating the need to truck contaminated soil through the community. Barge location and movements required authorizations from the Harbour Master. Land side access required access agreements between Transport Canada, the hotel, and the City of Victoria because the site has no direct access via roadways.

John Dewis, Senior Consultant, SLR Consulting (Canada) Ltd.
John Dewis is a Senior Consultant with over 14 years in the contaminated sites industry that specializes in the assessment and remediation of contaminated media. He acted as the project manager and provided technical guidance throughout the various phases of the project.

Michele Thompson, Senior Environmental Specialist, Public Service and Procurement Canada
Michele Thompson is a Senior Environmental Specialist with Public Service and Procurement Canada (PSPC). She is based in Vancouver and has over 10 years of experience in contaminated sites projects. During the Middle Harbour Fill Site remediation project Michele worked as PSPC’s senior project manager which included managing the overall project and procurement elements during planning and construction.

Eric Crawford, Environmental Advisor, Contaminated Sites Group, Pacific Region, Transport Canada
Eric Crawford is an Environmental Advisor with Transport Canada’s Pacific Region Contaminated Sites Group. During the Middle Harbour Fill Site remediation project Eric worked as Transport Canada’s project manager which included leading communications and stakeholder engagement.

When several groups have a vested interest in the health and productivity of an area, collaboration and cooperation between all is important. Preparation and forward planning to achieve the goals as a group is needed.

Lucy Islands was previously home to a staffed navigational light station. Decommissioned in 1988, the buildings were demolished or burnt, leaving residual debris across a portion of the island. Although vegetation has recolonized these areas, soil contamination, particularly lead, remains. Beginning in 2010, SNC-Lavalin Inc. was tasked with completing a detailed data gap assessment, additional soil and tissue investigation and a preliminary human health and ecological risk assessment (HHERA) of the island.

Lucy Islands has been designated as a conservancy and with that a collaborative management agreement is in place between government agencies and local First Nations. These agreements have established a framework to collaborate on the planning and management of the conservancy. The area is of cultural and archeological significance to local First Nations, providing food, medicinal plants, cultural items and goods as part of their economy. Lucy Islands is also inhabited by a variety of ecological receptors of concern, and most notably, is home to a globally significant breeding population of rhinoceros auklets.

The potential for contamination to adversely impact First Nations/recreational users, the rhinoceros auklets (sea birds) and other receptors was assessed in the HHERA. The HHERA was completed using a series of reasonable worst-case assumptions in accordance with federal guidance. Both direct (via soil contact) and indirect (via consumption of berries, seaweed and mussels harvested by local First Nations) exposures of humans to contaminants in soil were assessed. As the ecological evaluation was preliminary, risks were characterized primarily by comparisons of mean soil concentrations to federal soil quality guidelines. The HHERA identified several uncertainties, particularly for the protection of ecological receptors. Of significance, were the relatively few samples collected from an exposure unit occupied by a high concentration of auklet burrows (no good exposure model available for burrowing birds like rhinoceros auklets). Due to the limited window in which this exposure unit can be accessed (to prevent auklet habitat destruction) the characterization of contamination was limited and under-represented for the protection of both human and ecological receptors. Additionally, estimates of predicted risk to the auklet population from incidental soil ingestion, during burrowing, was uncertain based on unknown soil ingestion rates.

In the summer of 2019, through collaboration (as part of the management agreement) with Environment and Climate Change Canada (ECCC) wildlife scientists and First Nations on the findings of the HHERA, a plan was developed to further refine the risk estimates associated with ecological receptors. Supplemental site visits were planned and executed with representatives from both ECCC and local First Nations to collect additional data including blood samples (with co-located soil samples) from auklets to provide direct measurements of the lead body burden of auklets at worst-case exposure areas at the site. These additional data pieces are expected to reduce uncertainty in a future update to the HHERA and may allow for a revision of current risk management requirements for the site.

Christopher Trenholm, Project Scientist, SNC-Lavalin Inc.
Christopher Trenholm, P.Ag., is a Project Scientist with 14 years of experience in the environmental industry. Christopher has worked on federal/provincial government sites, municipal sites and commercial and industrial properties. Christopher has acted as an environmental field supervisor and project manager on a variety of projects involving organic and inorganic contaminants using both federal and provincial/territorial environmental regulations. His responsibilities have included project planning, budgeting and coordination, on-site supervision of contractors and subordinate field scientists/technicians, preparation of health and safety plans, data reduction/interpretation and technical reporting. Christopher’s project experience includes various industrial and commercial facilities including electrical substations, light stations, hydrometric stations, hatchery sites, field camps, small craft harbours and retail service stations. Christopher has significant experience conducting site investigations with soil, sediment, soil vapour, groundwater, surface water, porewater and tissue sampling programs at both local and remote site locations.

Giant Mine submitted its final closure and reclamation plan (CRP) in spring 2019. The CRP included four overarching goals, six principles, more than 30 objectives and over 150 criteria. The goals for the closure and reclamation of the site guided the development of closure objectives that are specific, measurable, and achievable. For each objective, criteria were developed that would facilitate confirmation that the objective was met. Giant Mine developed objectives and criteria for each main element of the remediation project, as well as overarching objectives and criteria for the whole site.

The development of the closure goals and objectives involved years of collaboration and integration with affected parties on:

• What should we do? (engagement and governance)
• What can we do and what are the trade-offs? (design engineering)
• What can we afford? (governance)
• What will the future land user want? (cooperation between local/Indigenous governments)
• What are the legal requirements? (Northwest Territories closure and reclamation guidelines)

With this input, Giant Mine set six foundational closure principles that form the ‘pillars’ of closure planning along with the overarching goals of the project. In line with common mine closure practice globally and territorial guidelines, these foundational principals included physical stability and chemical stability. With the support of the Yellowknives Dene First Nation, North Slave Metis Alliance, the City of Yellowknife and other reviewers, the project set four additional principles appropriate to an abandoned mine site: consider constraints on future use; minimize long-term active care requirements; incorporate input from affected parties; and, provide effective risk communication to future generations. Further, Giant Mine set a site-wide objective of including traditional knowledge in closure planning and implementation, wherever available and appropriate.

Even after substantive engagement, the question remained: When is it good enough? What is the appropriate yardstick to measure remediation success? In 2019, affected parties largely accepted the closure goals, principles and objectives. However, substantive revision was required to closure criteria to satisfy affected parties that the project could measure its own success and effectively report it to the public. Extensive engagement, deep understanding of the project by regulators and affected parties, and the vision for the post-closure landscape are all required to finalize meaningful closure objectives and criteria.

Hilary Machtans, Senior Fisheries Biologist, Golder Associates Ltd.
Hilary Machtans is a Senior Fisheries Biologist with 22 years of experience in fisheries, water quality, and environmental research. She was based in Yellowknife for 17 years (1997 to 2014) and is now living in Whitehorse, Yukon. Hilary's experience includes water and sediment sampling programs, fish habitat relationships, fish health, and contaminant assessment in relation to industrial effluent, fish population estimates, and habitat compensation planning. She also provides senior technical direction, project management, and regulatory advice. Hilary helps Crown-Indigenous Relations and Northern Affairs lead the environmental assessment at Faro Mine in the Yukon, environmental topics for Giant Mine in Yellowknife and other mines in closure.