Dillon Consulting Limited was retained to update a light non-aqueous phase liquid (LNAPL) conceptual site model (LCSM) and implement a site management framework that addressed outstanding data gaps around LNAPL and dissolved phase impacts associated with two areas at a former tank farm (i.e., Areas 1 and 2 of the Otter Creek Tank Farm) that historically contained eight above ground storage tanks ranging in size from 1,600,000 to 2,400,000 L. Using available data (both historical and data collected during the activities), Dillon evaluated primary lines of evidence of LNAPL behaviour scenarios which included LNAPL characterization, LNAPL stability (mobility of LNAPL around periphery of LNAPL body), LNAPL mobility (within stable LNAPL body), LNAPL recoverability, dissolved phase plume stability (i.e., Mann-Kendall and Ricker plume stability analyses), monitored natural attenuation, and natural source zone depletion (NSZD) evaluation using carbon dioxide and methane gas flux. The combination of stability, mobility, and natural source zone depletion evaluations were used to identify the appropriate site management strategy for the LNAPL plume that had in select wells more than one meter of LNAPL. Based on this study, the LCSM identified a behaviour scenario that demonstrated that there was no unacceptable dissolved phase or LNAPL mobility risk, which suggested a site management strategy could be used that did not require compositional control, saturation reduction or contaminant containment. The plume was able to be managed in place. This strategic approach toward achieving the objective resulted in significant costs saving (i.e., >$100,000) associated with optimized monitoring (reducing the number of wells sampled from 120+ to 82), use of innovative technology to measure CO2/CH4 flux, and timely and recurring data analysis that ultimately obviated the need for a round of data collection. This presentation will describe the weight of evidence approach (with multiple lines of evidence) and the associated data analysis/interpretation that permitted the reduction and subsequent cessation of monitoring and ultimately acceptance of no further action ahead of schedule.

Andrew Thalheimer, Partner, Dillon Consulting Limited
Andrew Thalheimer, P.Eng., QPESA, is a Partner with Dillon Consulting Limited in Dillon’s Halifax office and serves as Dillon’s National Remediation and Risk Control Leader. Andrew is a Site Professional and senior environmental engineer with over 30 years’ experience in various aspects of environmental liability management including due diligence, contaminated site investigation, risk assessment, risk management, remedial design, remediation, construction oversight, emergency response, litigation support, and strategic contaminated site management. Andrew has developed and implemented work plans associated with various phases of environmental assessment; groundwater monitoring optimization; human health and ecological risk assessment; LNAPL characterization, assessment, and management; environmental effects monitoring; and, remediation via multiphase extraction, in-situ chemical oxidation, capping, excavation, and bioremediation. He has successfully achieved regulatory closure on numerous LNAPL impacted sites through remediation and risk management.

The Paramount Small Craft Harbour (SCH) is located along the north shore of the main arm of the Fraser River in the Steveston Fishing Village area of Richmond, BC. The site consists of approximately 18.9 hectares, approximately at sea level. It is considered the main industrial area of the Steveston Harbour and hosts several tenants that include marine equipment and boat manufacture and repair, ship chandlery, net repair, travel lift, boat moorage, and an ice plant.

Paramount SCH, the Gulf of Georgia SCH and Shady Island form Steveston Harbour, which is administered by the Steveston Harbour Authority. Steveston Harbour is comprised of 38 parcels of upland properties and waterlots. Steveston Harbour is the largest commercial fishing harbour in Canada operated under the Fisheries and Oceans Canada (DFO) Small Craft Harbour Authority Program. The site has a long and diverse industrial history including various cannery operations dating back to the late 1890s, boat works, marine way operations and brick works since the 1930s, along with boat grids, infilling, material storage, bulk fuel storage and residential development.

There are no plans to divest or change the sites current use. Management priorities are to characterize and address the imminent risk to human health and the environment (if any) and reduce long-term liability. SLR Consulting (Canada) Ltd. assisted DFO with development of a long-term strategic plan using a risk-based approach to prioritize future assessments for the site to support current operations, and overall risk management strategy development. Previous site assessments have been executed on an area of environmental concern (AEC)-basis as opposed to an exposure unit basis. As a result, the current set of information for the site is fragmented and does not allow for a holistic evaluation of the entire site. A decision framework to assess the entire site will allow for assessment and remediation cost savings, and efficient prioritized long-term planning. The past AEC-focused investigations resulted in a high density of data over a small area of the site. This decision framework allows for defensible assessment and remediation decisions to be focused on the integrated Steveston Harbour site areas of highest risk and resulting in highest overall environmental benefit.

The decision framework will direct future decisions regarding environmental investigations and remediation at the site. For the areas of the site with data, this decision framework provides a stepwise risk ranking approach for each media that is based on the magnitude of contaminant of concern exceedances, complete exposure pathways, sensitive on-site receptors and overall benefit of the work, and expenditure.

For areas without data, this decision framework provides a method for evaluating the risk of the data gap and whether additional information should be acquired. The decision framework also provides site-wide triggers for when investigations are required. This framework can guide DFO in their future planning with a focus on site-wide risk assessment and long-term environmental liability reduction, allowing for more efficient spending, and providing greater transparency with tenants and other stakeholders.

Phyllis Bruleigh, Technical Discipline Manager, Land Quality & Remediation, SLR Consulting (Canada) Ltd.
Phyllis Bruleigh is a registered Professional Geoscientist and Project Management Professional with over 18 years’ experience in environmental consulting and project management. Her effective scheduling and planning of project resources is founded on a thorough understanding of the task at hand and listening to and understanding the clients’ needs. Phyllis’ successful project management has been demonstrated during her work in Phase I and Phase II ESAs, Stage 1 and 2 PSIs, DSI, Remediation, and Risk Management projects. Phyllis has overseen contaminated soil management and assessment for various government organizations such as Fisheries and Oceans Canada, Public Services and Procurement Canada, Defence Construction Canada, Indigenous Services Canada, and several First Nations. Previously, she worked with BNSF Railways, Port of Tacoma, and the United States Naval and Air Force departments. Her technical competence, awareness of security sensitivities, effective communication, and efficient use of resources has earned her long-term contracts with high-profile agencies. Phyllis stresses creating strong multidiscipline project teams with clear communication and a solid understanding of the client goals.

This abstract is a continuation of the Jericho Diamond Mine – Site Stabilization of a Remote Site presentation delivered at the 2018 RPIC Federal Contaminated Sites National Workshop.

The Jericho Diamond Mine is a defunct mine that Crown-Indigenous Relations and Northern Affairs Canada (CIRNAC) is responsible for managing. This presentation will briefly discuss the history of the mine, how it came to be under the care and control of CIRNAC, and the development and implementation of the site stabilization plan (SSP). It will then move on to focus on the on the development and implementation of the post-construction operation, maintenance and surveillance (OMS) plan.

The OMS plan for the Jericho site was developed after completion of the site stabilization activities in 2017. Development involved identifying and evaluating the residual risks at the site post-stabilization. The highly rated risks were then then incorporated into the OMS plan. The highly rated risks at Jericho are related to:

• Pit Lake Water Quality (Uranium Levels);
• Tailings cover – processed Kimberlite containment area;
• West dam breach; and,
• Petroleum hydrocarbon containment cell.

The initial phase of the OMS plan covers years 1-3 post-stabilization and implementation and began in 2018. Upon completion of the initial phase, the results of the OMS plan will be reviewed and the scope and frequency of the next phase of the plan will be determined.

Years 1 and 2 of the initial OMS plan have been completed and the results to date will be detailed, this includes reporting on the results for:

• Pit Lake water quality: Uranium levels are decreasing and water level is increasing;
• Tailings cover: Development of erosion channels and potholes, performing as intended;
• West dam breach: Re-establishment of water flow, performing as intended;
• Petroleum hydrocarbon containment cell: Warranty repair in 2018, performing as intended; and,
• Other observations.

Other items to be discussed include:

• The installation of a remote camera station in year 2 to observe the C1 Diversion and Pit Lake; and,
• Challenges and lessons learned during the site visits in 2018 and 2019.

Mark Yetman, Senior Project Advisor, Project Technical Office, Northern Contaminated Sites Branch, Crown-Indigenous Relations and Northern Affairs Canada
Mark Yetman is a Senior Project Advisor with the Project Technical Office of the Northern Contaminated Sites Branch of Crown-Indigenous Relations and Northern Affairs Canada (CIRNAC). Before joining the Project Technical Office he worked as a Project Manager in CIRNAC’s Nunavut Regional Office. During his time with CIRNAC he has worked on a number of contaminated site projects including the CAM-F Sarcpa Lake, FOX-C Ekalugad Fjord, PIN-D Ross Point and PIN-E Cape Peel Intermediate Distant Early Warning (DEW) Line Sites, as well as the Bear Island Mid-Canada Line Radar Station, Hope Lake and Jericho Diamond Mine. His previous experience includes time in both the private and public sectors in the fields of waste management and environmental enforcement. Mark holds a Bachelor of Science (Honours) and a Master of Environmental Science Degree from Memorial University of Newfoundland.

Background/Objectives.
The objective of this presentation is to discuss pertinent aspects of a project AECOM Canada Ltd. is completing with Nova Scotia Lands Inc. to remediate a long-standing public concern with respect to the development of and the impact from a landfill site located adjacent to a residential location near Halifax, Nova Scotia. The purpose of the study was to assess the current environmental condition both on-site and off-site in part resulting from the existence of a former construction and debris landfill site located in Harrietsfield, Nova Scotia. The study includes the review of several years of monitoring data and site works, a significant field assessment program to examine waste locations, types and characteristics as well as to study and understand site geological, geochemical and hydrogeological conditions for the purpose of providing to the Crown a recommendation for an effective site closure strategy within the Nova Scotia Contaminated Site regulations pursuant to the Nova Scotia Environment Act.

The current understanding of the site indicates that the construction debris taken in by the site was for the most part ground up into small fragments and placed in a partially lined containment cell constructed on fractured granitic bedrock. Once the cell was complete, the cap used to cover the cell contained a large percentage of silt and, given the hotter drier summers, over time it became desiccated and allowed precipitation to infiltrate the cell and dissolve and transport a chemical species into the fractured rock. This species, it would appear, played a part in dissolving uranium from the parent rock and likely impacted the groundwater to some extent and thus nearby production wells. Well water treatment systems and supply of bottled water to the community is currently being undertaken. This area has had a significant history of poor-quality groundwater prior to any development at the site although it is likely the site has contributed to the problem.

Following the closure approach recommendation and selection, project work included leachate removal and treatment within the existing cell and the design and tender specification development for the site closure. Subsequent project initiation for site remediation involves the collection and sorting of waste on-site for diversion, the proper disposal both on-site in the cell and off-site at approved waste facilities, the site reclamation and regrading, drainage control, leachate management, and capping of the landfill cell with an impermeable synthetic turf.

Approach/Activities.
This presentation provides an overview of the site, details regarding the investigation, data review, assessment and engineering required for the development of a sensible but scientifically effective and publicly acceptable closure plan for the landfill site. It will discuss how the province has involved the public especially the nearby community as stakeholders in the process and will outline how the province was successful in involving federal agencies to aid in secure funding both provincial and federal for the successful closure of a landfill project through the federal/provincial governments greening initiatives and within the mandate of the greenhouse gas reduction and climate change resiliency objectives.

Rob McCullough, Senior Technical Lead - Environmental Remediation, AECOM Canada Ltd.
Rob McCullough is a Senior Technical Lead - Environmental Remediation with AECOM Canada Ltd. Rob has experience in management, co-ordination and facilitation of significant response teams on large emergency response and remediation projects in Canada in the south and across the Northwest Territories and Nunavut. He has spent much of his career in the Canadian Arctic carrying out projects located in remote areas directing multi-disciplinary teams. Rob has overseen many integrity digs in pipeline maintenance programs and large complex projects across Canada and has 35 years of experience in the Arctic in the North West Territories, Nunavut, and in the Yukon and Greenland. Rob’s experience includes all aspects of remediation on a variety of projects including the Air Navigation System across the Canadian Arctic, the Distant Early Warning System (DEW line) and major releases from both upstream/downstream petrochemical companies across Canada and overseas in South east Asia and south America.

Rob was the senior technical lead for several projects including the MK Airlines 747 crash at Halifax International Airport, the remediation of JET A-1 and Arctic diesel releases at DND DEW Line BAF-3, former Colomac Gold Mine remediation, Bullmoose Ruth and Gordon Lake Group of Mines remediation and reclamation programs NT.

The Gloucester Small Arms Rifle Range (SARR) located near Bathurst, NB has not been used as a Rifle Range since the 1980s. The site has largely returned to a natural state (thick tree and vegetation cover), with the exception of the access road along the former firing lines. The former SARR is surrounded by mapped regulated wetlands and low-lying areas. Environmental site assessment work has been on-going since the mid-2000s and are currently on-going.

Areas of potential environmental concern were identified during the early work completed at the site and include: soil and groundwater at the firing lines and the stop butt; and, runoff or groundwater transport to surface water and sediment in the nearby freshwater aquatic life environments. Contaminants of potential concern (COPC) have mainly include trace metals; however, sampling for other COPC including polycyclic aromatic hydrocarbons, energetics, and per- and polyfluoroalkyl substances have been completed in soil, groundwater, surface water and sediment. As many of the metals identified in media at the site, including copper, zinc and lead are naturally occurring at concentrations above the applicable federal guidelines in many areas of NB, the challenge has been determining background concentrations vs. site impacts.

The site assessment process is nearing the end, as multiple rounds of sampling have been completed and impacts in soil and groundwater have been delineated. The next steps will include completion of a human health and ecological risk assessment to move the site toward federal closure.

Abigail Garnett, Senior Environmental Engineer/Hydrogeologist, GEMTEC Consulting Engineers and Scientists Limited
Abigail Garnett of GEMTEC Consulting Engineers and Scientists Limited has been in the environmental consulting industry for the past 18 years. She has obtained a Bachelors and Masters degree in engineering from Queen's University in Kingston Ontario. The focus of her work has been contaminated sites, human health and ecological risk assessments and hydrogeology projects.