The Northwest Territories went through a major change in governance in 2014 with the devolution of the administration and control of public lands, resources and rights in respect of waters from Canada to the Government of the Northwest Territories (GNWT). A major consideration during the devolution negotiations and process was how to manage federal contaminated sites, necessitating dedicating an entire chapter of the agreement to these “waste sites” (~20% of clauses). During Devolution, significant known federal contaminated sites were excluded from transfer, the majority of which are being addressed through the Federal Contaminated Sites Action Plan (FCSAP), with the intent of eventual transfer to the GNWT along with the surface and subsurface rights that are tied to them. It also created the Waste Sites Management Committee, which includes members from all signatories to the agreement, and provides an opportunity for parties to review, discuss and consider, and provide advice and recommendations to Canada regarding Waste Sites. The Devolution Agreement describes how sites are identified, how responsibility is allocated, and how the transfer of remediated sites to the GNWT is contemplated. The majority of the regulatory implications of this have been resolved, while nuances and interpretation continue to create challenges. There are therefore obligations, challenges and opportunities for custodians working in the Northwest Territories to develop strong projects with important inputs from all Indigenous partners, within this new complex regulatory framework.

Emma Pike, Program Manager, Contaminants and Remediation Division, Crown-Indigenous Relations and Northern Affairs Canada
Emma Pike has a Bachelor of Science in Ecology/Environmental Science as well as a Graduate Certificate in Project Management, and has worked on assessing, remediating, and monitoring contaminated sites in the North for nearly 20 years. She has successfully completed of a wide range of projects including DEW line sites, abandoned mines of various scales and types, as well as an orphaned sour gas well project. She is now the Program Manager for the Contaminants and Remediation Division with Crown-Indigenous Relations and Northern Affairs Canada based in Yellowknife, NT, addressing cross-cutting project issues and engagement support within a portfolio of FCSAP funded projects. She is also the regional lead for the Northern Contaminants Program, which supports research into long-range transportation of contaminants into the North.

Golder Associates Ltd. (Golder) completed visual geotechnical inspections at Distant Early Warning (DEW) Line landfills in the Baffin Region of Nunavut from 2015 to 2018 as part a DEW Line monitoring project on behalf of the Department of National Defence (DND). The purpose of the visual inspections was to evaluate the physical condition of the aggregate landfill covers to determine if they remain in stable condition or if observed changes suggest the need for further assessment or remediation. The inspection involved a detailed visual survey of landfill features by experienced geotechnical engineers to compare current conditions to previous inspections and identify any noteworthy changes which could impact future landfill performance. In 2018, Golder completed aerial drone surveys at six of the landfills at the Cape Dyer DEW Line Site located on the east side of Baffin Island 475 kilometres northeast of Iqaluit. The site is in a remote northern area with limited access; the available satellite imagery is limited in comparison to southern Canada. The climate and remote nature of the work posed a number of challenges for drone use. Notably, drones cannot be operated in high winds or fog, which frequently occur at DEW line sites. Wind shear is common at the DEW Line sites near to the ocean and can result in loss or damage resulting from drones blown off-course. The drone surveys were completed as a trial to evaluate the potential for drone technology to replace or reduce the frequency of the regular ground-based survey/visual inspection. This was completed by comparing the drone aerial photos taken at low altitude to the ground-based visual inspections.

Golder operated a fixed-wing unmanned aerial vehicle (UAV) which can fly a programmed flight plan taking overlapping photographs. A large number of discrete high-resolution aerial photographs were combined to create orthomosaic images of the landfills and the immediate surroundings. The images were further processed by photogrammetry software to develop a digital surface model. The orthomosaics were compared to the logged features from the visual inspections to determine if the features were recognizable on the orthomosaics and, if so, to assess how they present compared to ground-based visual observations.

UAV imagery was found to provide a valuable tool for preliminary screening of features for further investigation by ground-based visual inspection. The UAV imagery was useful for preliminary identification of larger features such as larger eroded areas, ponded water, variable moisture content, large cracks, tire tracks, staining and significant settlement. It was determined that the imagery cannot replace visual inspection by an experienced geotechnical engineer as some important features were not able to be identified through the use of UAV imagery alone. An advantage of the UAV imagery compared to visual inspection is the ability to view the landfills vertically from a higher elevation, which allows visualization of the entirety of some features and also provides a snapshot of the overall landfill condition at the time of the visual inspection. UAV images may be valuable to track year-to-year changes in some features like ponded water, moisture/seepage, staining and vegetation and could be used at landfills that are exhibiting problematic physical performance including seepage and staining.

Jamie Bonany, Project Scientist, Golder Associates Ltd.
Jamie Bonany has more than seven years of experience in environmental and waste management projects including contaminated sites, municipal solid waste landfills, bioreactor landfills, historic waste sites and quarries. His experience includes groundwater, surface water and landfill gas compliance monitoring; impact assessment; geotechnical/environmental well drilling, construction and testing; permit to take water (PTTW) and environmental compliance approval (ECA) monitoring at quarries and pits; water supply studies including the completion of pumping tests and water quality sampling and inspection; and, maintenance of purge wells and drains.

Jamie has experience working on remote work sites and in Northern Communities, including recent involvement in monitoring of DEW Line landfills at CAM-5, DYE-M, FOX-M, FOX-2 and FOX-3. He was responsible for the completion of monitoring reports for the soil and groundwater monitoring program. During this project he worked with and trained Inuit workers in Qikiqtarjuaq and Hall Beach. Jamie was also involved on a fuel spill remediation project in Nunavut where he was responsible for the coordination and completion of monitoring on site, including surface water and soil sampling.

The Northern Contaminated Sites Program (NCSP) manages 164 contaminated sites across the Canadian North. Many of NCSP’s contaminated sites are the result of former mining or mineral exploration activities, former military activity, or other industrial activities. All of NCSP’s sites are located in northern climates and often in remote locations. Although there are a significant number of publications providing guidance or best practices for contaminated site remediation and mine site reclamation, this guidance is often based on scientific understanding and experience developed at southern sites.

The northern location of the NCSP’s sites poses particular challenges to contaminated site management, including short field seasons, cold temperatures, the presence of permafrost and delicate northern ecosystems. Northern-specific approaches are often required. To help improve the understanding of northern contaminated sites and develop approaches that are effective in a northern context, the NCSP has often partnered with research institutions to support advances in scientific understanding of northern environments, and the effectiveness of remediation approaches in the North. Our participation has ranged from funding of research networks, to participation of in workshops, and from providing in-kind contributions of transportation and accommodations to allow researchers to access remote locations, to facilitating on-going, long-term research at our sites.

This presentation will describe the benefits and opportunities for federal custodians associated with participating and supporting research during our remediation projects, as well as the challenges faced by the NCSP in facilitating research at our sites. The presentation will also discuss both the risks associated with welcoming researchers to federal contaminated sites, and the key lessons learned through our experience.

Siobhan Sutherland, Project Analyst, Project Technical Office, Northern Contaminated Sites Branch, Crown-Indigenous Relations and Northern Affairs
Siobhan Sutherland is a Project Analyst with the Project Technical Office of the Northern Contaminated Sites Branch of Crown-Indigenous Relations and Northern Affairs. She has a B.SC. in Environmental Sciences, with a Specialization in Geology. She worked for several years as an exploration geologist before working as an environmental consultant where she practiced human health and ecological risk assessment and eventually lead the Ottawa office’s multidisciplinary Environmental Health Sciences Team. In her current position she provides technical and project management advice and support to regional project managers to ensure the successful completion of complex contaminated site remediation projects in the North. Her area of expertise is the incorporation of risk assessment into remedial and project planning. She is a professional geoscientist.

Management of federal contaminated sites (FCS) has been going on since 1989 when the Canadian Council of Ministers of the Environment and the Government of Canada negotiated a joint $250-million, five-year National Contaminated Sites Remediation Program. Then in 1990, Environment and Climate Change Canada committed $25 million over five years to assist custodians with identifying, assessing, and remediating high-risk contaminated sites. The need for standardization across departments and sharing in best practices generated the creation of the Contaminated Sites Management Working Group (CSMWG) in 1995. The CSMWG began working on a new Federal contaminated sites program in 1998 and by 2002, the Treasury Board of Canada Secretariat launched the Federal Contaminated Sites Inventory. Federal contaminated sites had now officially entered the age of the Internet...and what an initial bumpy ride that was! Baby Boomers and Gen X led the management of FCS during the last 15 years of the Federal Contaminated Sites Action Plan (FCSAP). Gen X’ers are taking over the program with Millennials and Gen Z joining the workplace supporting project management roles as the Baby Boomers retire. Since 2005, many new players have appeared and grown their social influence on programs and projects: Internet, smart phones and social media platforms such as Facebook, Instagram and Twitter. As we roll into the new phase of the FCSAP, the workers, technology, and social media are all changing so quickly. Gone are the days of paper reports and regional silos. Millennials have grown up in a time where information has become available instantly. Through a Google or Wikipedia search, answers to even quite complicated questions can be found. As such, millennials have developed into a group that wants to work on new and tough problems, and ones that require creative solutions. They are well educated, skilled in technology, very self-confident, able to multi-task, and have plenty of energy. They do, however, realize that their need for immediate results in their work may be seen as weaknesses by older colleagues. As for the Gen Z, they are the first fully digital generation, and yet, they yearn for human interaction at work. In fact, 90% of Generation-Z reports wanting some form of human element woven into their work. This means a workplace needs to provide the tech aspect with a twist of human connection. So how are FCS managers going to adapt to the speed of information, fake news and social media pressures? What effect could these new generations and technologies have on FCS management in the future? Are these even relevant questions? How can we use the Internet and social media in support of management of FCS? Is there a difference between the private sector and the feds with regards to these questions? This presentation will provide some insights on these questions and hopefully initiate a new way of seeing the FCSAP Program.

In-situ solidification/stabilization (ISS) has been used at many manufactured gas plant (MGP), brownfield and Superfund sites. ISS mixes cementitious reagents with contaminated soils reducing the bioavailability and leachability of contaminants. ISS can also be optimized to control certain soil characteristics, such as compressive soil strength and reduce hydraulic conductivity. Various reagents are used to promote ISS including Portland cement, blast furnace slag, lime kiln dust, etc. Several of these reagents contain calcium oxide (CaO), also known as quick lime. For example, Portland cement (PC) consists of 60% to 68% CaO by weight.

ISS is often applied at highly contaminated petroleum hydrocarbon sites decreasing the leachability of benzene, toluene, ethylbenzene and xylene (BTEX), naphthalene (NAP) and other organic contaminant in soil. Cementation reactions also decrease hydraulic conductivity (K), which diverts groundwater flow away from the solidified/stabilized soil. ISS treatment also increases unconfined compressive strength (UCS), often critical for redevelopment.

However, high concentrations of organic contaminant can interfere with cementation reactions requiring excessive application of amendments increasing both amendment and disposal costs of the displaced soil. This ISS limitation can be minimized by utilizing a combined remedy approach like in-situ chemical oxidation (ISCO) to degrade some of the organic contaminants present. ISCO combined with ISS has been found to be able to achieve the same or better leachability and compressive soil strength values with less overall reagent addition and displaced soils. Combining one or more remediation technology generates synergies by exploiting the strengths and minimizing the weaknesses inherent in individual technologies. When successful, combining remedies enhances performance and/or reduces costs compared to each technology used alone.

This presentation will review the advantages and limitations of using the combined ISCO/ISS remedy on a contaminated soil from different petroleum hydrocarbon sites. The presentation will review current literature and explore both bench and field data demonstrating the successes of ISCO-ISS as a combined remedy.

The objectives of this study generated by Srivastava et al. were to quantify:

- The ability of a wide range of doses of ISS-activated sodium persulfate (SP) to degrade BTEX and polycyclic aromatic hydrocarbons (PAH);
- The impact of BTEX and PAH removal from chemical oxidation during ISCO/ISS treatment on synthetic precipitation leaching procedure (SPLP) measurements, compared with a wide range of ISS doses alone; and,
- The effect of activated PS on other ISS performance parameters, such as hydraulic conductivity and unconfined compressive strength. Results/Lessons Learned.

Activated SP chemically oxidized a significant portion of the contaminants of concern (COC) for all the ISCO/ISS treatments, and the mass of COCs oxidized increased with increasing SP dose. The lowest molecular weight contaminants were preferentially oxidized. For the same PC dose, combined ISCO/ISS treatment was more far effective in reducing contaminant leachability than ISS treatment alone, because of the COC removal achieved by the ISCO (activated SP) component.

Jean Pare, Vice President, Chemco Inc.
Jean Pare, P.Eng., has a degree in Chemical Engineering from Laval University. He has been involved for the last 25 years in the evaluation, development, design, and promotion of both conventional and innovative environmental technologies. As Vice President with Chemco Inc., his responsibilities include the remediation design, technico-economical analysis and technology supply for chemical oxidation and reduction, soil washing, and enhanced bioremediation. Last year, he worked with over 400 sites, applying his expertise to various types of organic and inorganic contaminants in soil and groundwater. He is also involved with many environmental organizations such as Canadian Land Reclamation Association, Canadian Brownfields Network, Environmental Services Association of Alberta, British Columbia Environment Industry Association and Reseau-Environnement where he is an active technical committee member and regular technical speaker.

A comprehensive understanding of the transport and fate of per- and polyfluoroalkyl substances (PFAS) in the subsurface is critical for an accurate conceptual site model (CSM), risk assessments and design of effective remedial actions: an economical substitute for Swiss cheese sampling. A key challenge in developing conceptual and numerical fate and transport models for PFAS contaminated sites is to identify, quantify and apportion various mass removal processes controlling PFAS concentrations and distribution in the subsurface. Conventional approaches and numerical simulation platforms for fate and transport modelling of other contaminant classes may need to be adjusted and/or enhanced for PFAS.

Substantial knowledge gaps in terms of our understanding of the subsurface distribution of PFAS should be considered for PFAS fate and transport modeling. These challenges, according to National Ground Water Association (2017), include (1) complex mixtures of molecules comprising PFAS; (2) combined hydrophobic/hydrophilic nature of the PFAS molecules that strongly affects their sorption and mobility; (3) role of co-contaminants such as non-aqueous phase liquids (NAPLs); (4) limited data on transport-related properties of PFAS aside from perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) (e.g., precursors); (5) challenges regarding precursor identification, quantification and their role in sustaining a downgradient contaminant plume; (6) complex sorption mechanisms; (7) PFAS retention mechanisms in the unsaturated zone; (8) groundwater/surface water interactions; and, (9) limited data on PFAS atmospheric transport and subsequent deposition. One additional gap is uncertainties regarding the history of PFAS use and the history of mass release at the impacted sites.

PFAS offers a unique opportunity to break out of routine analysis and presents an interesting set of new challenges in terms of fate and transport modelling. It is exciting to see how different modelers have tried to approach this challenge and to follow the development or expansion of modelling software capabilities to investigate fate and transport properties that had previously been unknown. This study presents an overview of the key fate and transport mechanisms of PFAS and presents a literature review of a few existing PFAS modelling studies, their limitations, advantages, and lessons learned. In addition, a sensitivity analysis to determine key parameters controlling PFAS fate and transport will be performed on conceptual models using field data sets. The critical review of existing PFAS modelling work has identified some important knowledge gaps and modeling challenges related to parameters and processes which control PFAS fate and transport. To gain the most benefit from modeling, we show that the conceptual model must be well defined and justified and that uncertainties must be considered.

Mahsa Shayan, Environmental Engineer, Canada Region, PFAS Lead, AECOM
Dr. Mahsa Shayan is an environmental engineer with over 10 years of professional and research and development (R&D) experience in environmental site characterization and remediation, specializing in contaminant fate and transport studies and remedial options analysis for sites impacted by a wide range of emerging and conventional contaminants. Mahsa’s experience also includes subsurface contaminant fate and transport analyses using numerical models, and application of environmental molecular diagnostic tools, including compound specific isotope analysis and molecular biology techniques. Over the past two years, Mahsa has been focused on PFAS and served as the Canada Region PFAS Lead at AECOM. During this time, she has served as the PFAS Technical Expert involved in PFAS projects, familiarized with PFAS analytical testing and sampling methodologies, and prepared proposals and work plans for a wide range of clients.