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Metro Toronto Convention Centre 
255 Front St West, North Building, Toronto Ontario 
June 13-15, 2018 

Stream 10 – Innovative, Green and Sustainable Remediation
Remediation of the Goose Bay Stillwater Lakes and Dumps
Michael Charles, Stantec Consulting Ltd.
The objective of this presentation is to provide an example of the application of innovative, green and sustainable remediation methods.

Over the past 60 years, Canadian and other air force groups have used the Goose Bay airbase as a base of operations, refuelling and training. During that period, thousands of tonnes of garbage, drums, hazardous waste liquids and industrial debris have been dumped throughout a 40-hectare forest and lake area adjacent to this northern base (the lower Stillwaters). In 2016, the Department of National Defence undertook a multi-million dollar program to remediate the impacted escarpments, woodlands and lakes. The work involved review of dozens of historic reports, supplemental pre-design testing and studies, extensive groundwater and surface water modeling, and public stakeholder engagement to realize the optimal remedy.

This presentation will discuss the final design which adopted an innovative sustainable remediation approach, leveraging many of the natural groundwater, surface water and geologic conditions to provide long-term control of contaminated groundwater, buried drum dumps and impacted sediments at a fraction of the cost of conventional landfill remediation methods. The approach included the passive treatment of impacted groundwater plumes discharging to lake systems from the adjacent military base using engineered wetlands; the removal of surface wastes/debris; soil capping; in situ sheet-pile containment cells; and, a long-term monitoring program to verify performance expectations. This presentation will provide a summary of the unique challenges posed by this northern site, the adaptive methods used to remove risk in a passive cost-effective manner, and restore the area to a functional woodland and lake system.

A Modified Site Investigation and Risk Assessment Approach to Closure of Small Remote Waste Disposal Site
Jeff Christie1, Trish Miller2, Reidar Zapf-gilje3, Ananthan Suppiah4, Taylor Ambler4
1Golder Associates Ltd.
2TAM Environmental
4Indigenous Services Canada
The objective of this presentation is to provide the framework of using a modified site investigation approach and complimentary risk assessment to support the sustainable closure of remote First Nation waste disposal sites.

Waste disposal options have historically been limited or unavailable to many remote, predominantly First Nation, communities throughout Canada. The absence of waste reduction programs in these communities has resulted in the creation of un-regulated, non-engineered, waste disposal sites. These sites were often selected out of convenience near communities and therefore, presented potential risks to both human and environmental health, as well as a variety of secondary issues such as: nuisance wildlife, increased vermin presence (i.e., rats), wind-blown refuse and odour/eyesore complaints.

In 2009, Indigenous and Northern Affairs Canada (INAC), now the Department of Indigenous Services Canada (DISC), in British Columbia began a program to address small, remote, First Nation community needs for sustainable and environmentally responsible solid waste management practices. Solid Waste Working Groups within communities were formed to engage community members in a two-way discussion on how to manage decommissioning the existing waste disposal sites and develop new community-specific solid waste management practices. Given the limited access at many of the sites and relatively small volumes of waste, comprised of primarily household domestic refuse, the most feasible solution to decommissioning the sites was one of closure in-place. This solution was contingent upon certain risk factors (e.g., consideration of drinking water wells, no enclosed structures developed on the site) so that human health and the environment are protected.

A modified site investigation approach, based on CCME guidance, was developed for these sites as the standard approach is focused on identification of where contamination may be present, while the location and extent of waste in these remote waste disposal sites is known. The investigation needed to focus primarily on contaminant migration pathways such as leaching to groundwater, volatilization to air and erosion with soil to downgradient locations. Innovative investigation methods were used, particularly related to evaluation of leachate, as it was not always possible to obtain groundwater data.

A risk assessment was conducted based on future conditions when an engineered cap is placed over top of the waste material, preventing direct contact of humans and ecological receptors with contaminants in the waste material. Therefore, the focus of the risk assessment becomes an evaluation of potential exposure through migration pathways, including inhalation of vapours; consumption of downgradient groundwater; potential uptake of contaminants from groundwater in food items for people and wildlife; and, potential contamination of downgradient surface water for people and wildlife. A conceptual site exposure model was developed to describe the contaminant source, migration pathways and potential exposure pathways to humans and wildlife; how potential exposure pathways have been evaluated to communicate assessment methods; and, give piece of mind to people in the communities.

Since 2009, numerous partners have worked to close legacy waste disposal sites in 12 remote First Nation communities in BC using locally sourced soil or rock as cover material. From a green technology and a sustainability perspective, this remediation approach scores high: i) it is low in terms of greenhouse gas emissions; ii) the contamination is addressed locally using locally sourced material; iii) it is supported by the local communities; and, iv) it was the lowest cost remediation option.

Laser Induced Fluorescence and Non-Aqueous Phase Liquids: A Perfect Match?
Ben Sweet, SCG Industries Limited
Kathy Cooper-MacDonald, Fisheries and Oceans Canada 
The objective of this presentation is to help stakeholders better understand LNAPL and laser induced fluorescence technology to improve their site management processes in the context of evolving regulations and state of practice.

The advent of high-resolution site characterization (HRSC) technologies has lead to a paradigm shift in contaminated site management. HRSC technologies are diagnostic field tools that leverage sophisticated analytical methods in the field to rapidly produce scale appropriate data in real-time. The speed of assessment and high density of representative data empower the implementation of strategic, cost-effective management plans.

A critical area of advancement is in the management of non-aqueous phase liquids (NAPLs). NAPLs pose a direct and indirect risk to human health and the environment, often serving as long-term sources of hazardous contaminants. NAPLs have traditionally presented challenges for management due to their unique physical and chemical properties, which make them difficult to characterize and remediate in the subsurface.

Laser induced fluorescence (LIF) spectroscopy has been adapted for the in situ assessment of petroleum hydrocarbons in soil and groundwater. One application (ultra violet optical screening tool) involves driving a fluorometric probe into the subsurface while gathering continuous data on the spatial distribution, type, and relative concentration of hydrocarbon contaminants at the centimetre scale. This technique provides the data necessary for the production of robust conceptual site models, a foundational step in the development of effective management strategies.

This technology, in addition to practical and academic research, has advanced the state of NAPL science leading to changes in regulation and management practice. At this critical juncture, this presentation seeks to share insight and lessons learned from multiple case studies utilizing LIF for LNAPL management. Focus will be on data interpretation and utilization to inform decision-making on risk management and remediation. Lessons learned from these cases will examine the strengths and limitations of this approach and how to strategically integrate the technology into site management plans. This technical insight will be shared in the context of relevant regulatory and FCSAP program processes.

Innovative Sampling Techniques to Support Natural Recovery
Amy Corp1 and Shauna Davis2
1Anchor QEA
2Defence Construction Canada
The objective of this presentation is to highlight several sampling techniques that can be used to assess the potential for an aquatic site to naturally recover.

Natural recovery predictions can be essential in the long-term management of contaminated sites. It is the process by which contaminant concentrations in sediment are reduced through a combination of physical, biological and chemical processes so that sediment concentrations in bioactive zones of the sediment (i.e., near the surface) reach acceptable levels within a reasonable timeframe. Physical processes include burying contaminated surface sediments with cleaner incoming sediments and mixing the new clean sediments with deeper and more contaminated sediments through bioturbation, propwash and other processes. Biological processes, particularly bacteria-mediated biodegradation, can be effective at breaking down certain organic compounds, thereby reducing their mass and toxicity. Chemical processes, such as adsorption of contaminants onto organic carbon or clay minerals that renders them unavailable to food chain receptors, can also contribute to natural recovery.

Natural recovery of contaminated sediments is often evaluated through multiple lines of evidence using empirical monitoring data. Designing and executing quality, cost-effective sampling programs can be challenging, particularly for larger projects using natural recovery evaluations and models. This presentation will describe several sampling techniques, including radionuclide sampling, sediment traps, and high-resolution cores, along with the objectives for using each technique and how the data can be applied to natural recovery evaluations.

The evaluation of natural recovery in Esquimalt Harbour will be used as a case study using multiple lines of evidence to support monitored natural recovery assessments. In this case, sampling was conducted to fill data gaps regarding rates of sediment deposition, concentrations of depositing sediment, temporal and vertical contaminant trends in the sediment bed, and the depth of mixing by bioturbation or propwash. Based on these objectives, a sampling strategy was developed and implemented. Lessons learned from conducting the sampling program will be shared.

These data supported development of a predictive model that simulates sediment deposition and mixing as the primary processes controlling long-term surface sediment concentrations. The study data were used to refine concentrations of settling particulate matter and resuspension rates and validate the natural recovery model, which provides bounding-level estimates of future recovery. Concentration trends were also evaluated using historical data and sediment cores as further lines of evidence to support the predictions that surface sediment concentrations in the Harbour will reach acceptable levels within approximately 30 years after completion of several localized remediation projects. Predictions from this evaluation were used to guide the development of a comprehensive plan for remediation and long-term management of Esquimalt Harbour.

Techniques for Understory Kelp Salvage and Recolonization of Disturbed Sites to Mitigate Temporal Habitat Loss
Peter Troffe1, Doug McMillan1, Gina Lemieux2, Ashley Park2, Shauna Davis3, Michael Bodman3
1SNC-Lavalin Inc.
3Defence Construction Canada
The objective of this presentation is to present a novel approach to mitigate serious harm to fish.

Defence Construction Canada, on behalf of the Department of National Defence (DND), undertook dredging in Constance Cove, Esquimalt Harbour, as part of DND's multi-year, harbour-wide sediment remediation program. One of the mitigation measures recently implemented with the Constance Cove remedial dredging is the salvage of understory kelp within the project's dredge footprint prior to the dredging; the relocation of salvaged material to a temporary storage area; and, restocking once construction is ultimately complete. These kelp salvage measures are intended to address impacts of temporal fish habitat loss due to dredging activities in an area with an existing kelp bed, and to reduce the succession time required for a disturbed area to return to a functioning kelp habitat.

Understory kelp provides important functions supporting the productivity in Esquimalt Harbour for local Harbour commercial, recreational and Aboriginal (CRA) fish species such as Pacific herring, rockfish, Pacific salmon, greenling, sea perch, among others. The understory macro algae Saccharina latissima (sugar kelp) was the primary target species for salvage in areas within the dredge footprint that had greater than 25% cover attached to salvageable rock substrate. During the storage of salvaged kelp and substrate, kelp enhancement lines, employing locally developed kelp cultivation techniques, were installed to provide an additional source of spores to inoculate the salvaged substrate, as well as provide additional temporary fish habitat during construction activities. Methods and preliminary results will be discussed.

Plant-based Solutions for Remediating Salt-Contaminated Sites
Barbara Zeeb1, Kassandra Yun1, Logan Morris1, Ellen Mann2, Allison Rutter2
1Royal Military College of Canada
2Queens University
The objective of this presentation is to highlight the use of vascular plants to assist with remediation of contaminated sites.

Soil salinization can occur from natural processes such as the weathering of high salt content minerals, the deposition of salt from wind and rain, or the movement of salts from the ground water table to the soil surface through capillary action. Agricultural practices involving land clearing and excessive irrigation can exacerbate these natural processes, while other anthropogenic activities, such as road salt application, industrial spills, or the landfilling of industrial waste materials, can result in cases of soil salinity that are more acute. Here we present two examples of where vascular plants can assist with the remediation of acute cases of salinity contamination.

Canada is the largest user of salt per capita, and the majority of that salt use is as a de-icer on our roads. De-icing salt is generally a combination of sodium and chloride (NaCl) or common table salt. Much of the salt applied during de-icing operations is pushed to the roadside by highway clearing operations and by vehicular traffic. These chemicals can then flow into surface and ground water affecting aquifers, wells, wildlife, flora and drinking water. While these effects have long been publicized, road salt continues to be heavily used due to its low cost and a lack of viable alternatives. Atriplex patula is a widely distributed halophyte in Canada, and is often found on disturbed ground including roadsides. Given these qualities, A. patula is a good candidate species for the phytoremediation of salt-impacted soil in Canada. We are evaluating the efficacy of this halophyte in the phytoextraction of NaCl from contaminated roadside soil in Ontario and Newfoundland using both field and greenhouse studies.

Cement kiln dust (CKD) is a high salinity by-product (waste material) from the cement production process that is generated during the heating of raw materials in cement kilns. In this case, the dominant salt ions are potassium (K+) and chloride (Cl-). CKD is not considered a hazardous waste in Canada, and as salt is not a regulated contaminant, landfills and their saline leachate are free to impact surrounding environments. In previous work, resident Phragmites australis was found to phytoextract large quantities of the dominant salt ions from a CKD site in Bath, ON. Although phytoextraction proved very effective at this site (with a potential to remediate it in 7-9 years), due to the invasive variety of P. australis, this phytoextraction work cannot be applied to the hundreds of other CKD site in Canada. Hence, two native halophytic grasses, Distichlis spicata and Spartina pectinata, were identified as having potential to remediate the soil via excretion and subsequent haloconduction. Analytical work using X-ray dispersive scanning electron microscopy was carried out to characterize the salt crystals. Multiple trials were carried out both in the field, and under controlled conditions in the greenhouse in order to determine the most efficient way to collect dispersed salt particles over varying distances. These data are now being used to model salt dispersion patterns over space and time, in order to determine the effectiveness to remediate salt-impacted soils using recretohalophytes.

Use of an Ecosystem Approach for Sustainable Remediation of a Fuel Spill at a Logging Camp on a Remote First Nation Reserve
Trish Miller1, Suzanne Simard2, Jeff Christie3, Siege Pflug4
1TAM Environmental
2University of British Columbia
3Golder Associated Ltd.
4Indigenous Services Canada
The objective of this presentation is to outline the application of ecosystem functionality as a key factor in weight of evidence risk assessments and developing sustainable remediation strategies.

Fuel spills have been a common occurrence in remote communities, logging camps and other remote developments. Remediation of these spills using excavation, transport and disposal can be effective in removing the source material but is often not completely effective. Remedial excavations are also not a sustainable approach nor consistent with Canada’s climate change strategy initiatives as excavation and transport result in significant greenhouse gas emissions during the transfer of contaminated soil from one location to another.

For this site, a remedial excavation was conducted to remove the source area of contamination, but contamination was found to migrate through a terrestrial riparian zone to a fish-bearing stream. Based on visual inspection during the remedial excavation, the terrestrial riparian zone was a mature functioning ecosystem containing mature trees more than 100 years old. An ecosystem approach was used for the assessment and remediation of potential impacts of the fuel spill on the aquatic and terrestrial environments. A key addition to the standard risk assessment approach of assessment of chemistry, toxicology and community was the addition of basic ecology data to improve understanding of ecosystem functionality. Using this ecosystem approach, we collected data to answer two fundamental questions: i) are the contaminated terrestrial and aquatic environments functional ecosystems; and ii) would further excavation of contaminated soil and sediment result in a greater negative impact than leaving the site intact?

For this fuel spill site on the remote north coast of BC, the field program was designed to answer these questions and included: i) enumeration of species diversity and abundance; ii) evaluation of indicators of health and toxicity testing; and, iii) habitat quality and measures of habitat use. For the aquatic environment, the triad weight of evidence approach commonly used for aquatic environments was used. A similar approach was used for the terrestrial environment. The site was classified as site series 14 CwSs – Skunk cabbage (Swamp forest) in the sub-montane very wet maritime coastal western hemlock (CWHvm1) variant according to the BC Ministry of Forests Lands and Natural Resources Operations website. This immediately provided information on the landscape profile, the expected species composition and the edatopic grid. This information was used to evaluate if there were species missing from the assemblage. Additional lines of evidence included: soil structure, presence of sensitive species, percent plant cover, presence and abundance of sentinel species, observations of plant health and wildlife use.

The results of this ecosystem-based assessment found that the terrestrial and aquatic environments served as functional ecosystems. Excavation of remaining contamination would have resulted in destruction of the ecosystems. Recovery of the ecosystems following excavation to the current functionality would take more than 100 years, as pedogenic processes would need to establish to rebuild the soil community before trees could be supported. Using this approach, the recommended remediation strategy for the fuel contamination was a combination of source removal, risk assessment and monitored natural attenuation. This approach was discussed with and accepted by the First Nation.

Sediment Clean-up Using Activated Carbon – Case Studies for Recent Application and Success
Dan Berlin, Tom Wang, Matt Woltman
Anchor QEA
The objective of this presentation is to provide recent case studies examples of activated carbon use as a remedial technology for contaminated sediments.

This presentation will discuss the application of activated carbon (AC) as a remedial technology for the clean-up of marine and freshwater sediment sites in the United States and Canada. AC amendments have been demonstrated to be an innovative and reliable technology for addressing contaminants in sediments. The use of AC as an amendment in engineered sediment caps or as a standalone, in situ treatment technology has become increasingly more common to address sediment contamination, particularly where access is restricted (e.g., in underpier areas).

AC has been demonstrated to sequester and immobilize several contaminants when mixed directly into sediment, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), dioxin/furans, DDT, and mercury. AC can adsorb 10 to 100 times more hydrophobic organic contaminants than adsorption to organic carbon. Field studies have shown significant reductions in sediment porewater contaminant concentrations and biouptake, to as much as 99% in porewater and 90% in tissue.

The general approaches for applying AC will be reviewed, including: 1) directly applying a thin-layer AC amendment to surface sediment with or without surface mixing; and, 2) incorporating AC into a pre-mixed, blended cover material of clean sand or sediment, which is also applied to the sediment surface. Generally, AC placement is less disruptive and less expensive than traditional sediment clean-up technologies such as dredging or isolation capping. Site-specific considerations include potential benefits, risks, ecological effects and costs relative to other treatment technologies. Several case studies in the United States and Europe will be presented from the past decade of pilot- or full-scale sediment remediation projects that used different applications of AC, but still resulted in substantial reductions of contaminant concentrations in porewater and tissue. Updates will also be provided for projects that are incorporating placement of AC amendments into the remedial design, including projects in the Lower Duwamish River (Seattle, Washington) and Esquimalt Harbour (British Columbia).

Remediation of Chlorinated Solvents in Groundwater Using Carbon Amendments: Analytical Challenges and Solutions
Heather Lord1, Eric Veska2, Samantha Clay1, Atena Georgescu1, Mariana Cojocar1
1Maxxam Analytics
2Stantec Consulting Ltd.
The objective of this presentation is to provide an introduction to the in situ remediation of chlorinated solvents in groundwater with liquid activated carbon and demonstrate its use for remediation at two sites.

Carbon amendments are proving highly effective for remediating chlorinated solvents such as vinyl chloride, tetra- and trichloroethylenes and 1,2-dichloroethane, in groundwater plumes. However, in some cases the presence of the carbon amendment in samples submitted for laboratory analysis interferes with the analysis itself. Internal standards and recovery surrogates spiked into field samples for quality control (QC) purposes can have response levels significantly outside of acceptable laboratory control limits. In such cases, samples are diluted to eliminate the matrix interference, resulting in acceptable QC data but at the same time raising reporting limits to levels that exceed generic or site-specific clean-up guidelines, hence limiting the data utility for evaluation of remedial performance.

In normal practice, after injecting the amendment solution into a groundwater plume, the liquid activated carbon is expected to settle out of solution in the subsurface with time, such that after a certain residence time a sample of groundwater may be withdrawn from a monitoring well without entrained amendment. At this point, standard analytical protocols are used to verify remedial success.

It may sometimes be necessary to sample groundwater and verify that guideline limits have been achieved before the carbon amendment has completely settled. In such cases, the sampled groundwater can have a noticeable black or cloudy appearance. Considerable matrix interference is typically seen in these types of samples resulting in unacceptable QC spike recoveries. This is not unexpected as spiked standards and recovery surrogates have similar chemical properties to the chlorinated solvents themselves, and so, should be sequestered by the carbon amendments just as effectively as reported parameters.

Alternative approaches to both groundwater sampling using low flow technique and passive diffusive bags and laboratory sample calibration were evaluated for their effectiveness in reporting halogenated compound concentrations in carbon-amended groundwaters to their lowest possible detection limits. Samples of groundwater were collected and analyzed from two sites; one site with groundwater containing high concentrations of chlorinated solvents and the second site with groundwater containing much lower concentrations of chlorinated solvents. In this presentation, we will describe our current approaches for sampling and analysis of chlorinated solvents in groundwater samples containing carbon amendments that interfere with standard analytical protocols, along with recommendations on sampling and sample submission.

Case Studies: Overcoming Annoying Contaminant Rebound Using Adsorptive Technologies
Kevin French, Vertex Environmental Inc.
The objective of this presentation is to provide an overview of innovative and new adsorptive-based remediation technologies that can be used to overcome organic contaminant “rebound” in groundwater caused by back diffusion from soil or bedrock matrices.

Organic contaminants in groundwater, including chlorinated volatile organic compounds (cVOCs) and petroleum hydrocarbons (PHCs), often represent significant legacy environmental concerns at brownfield and other contaminated sites. Soil is often quickly and easily remediated. However, relatively minor residuals of contamination remaining in the soil (or bedrock) matrix, even at concentrations below soil quality standards, can result in “rebound” of the compounds in groundwater to concentrations above actionable standards. This is due to the slow and steady back-diffusion of the organic contaminants out of the solid matrix over time. This phenomenon, combined with the orders of magnitude lower concentrations typically allowed in groundwater, is problematic for site closure.

Many common in situ remedial technologies have significant limitations including: the requirement for multiple applications of amendments; effectiveness limited to specific contaminants and not others; and, low persistence, low efficiency, potential for generation of more toxic degradation products. Most of these approaches also require relatively long timeframes to implement (months to years).

In the past several years, first-hand observations have noted that injecting activated carbon (AC)-based amendments can be used to provide a quick, effective and sustained treatment for cVOCs, PHCs and other organic contaminants in a matter of weeks. Previously the use of AC in the subsurface was limited due to the finite adsorptive capacity of the AC emplaced. However, new technologies allow for both adsorption and subsequent treatment of organic contaminants using efficient modalities. cVOCs are treated via the well known chemical reduction pathway. PHCs are treated via anaerobic biodegradation, which provides a more efficient and sustained treatment compared to aerobic biodegradation. As contaminants are degraded, adsorption sites on the AC once again become accessible to quickly adsorb more contamination from the groundwater, thus overcoming the “rebound” problem. These technologies can be injected or directly mixed into site soils to remediate plumes or even to form permeable reactive barriers (PRBs).

Real-world, Canadian case studies of sites where these innovative in situ remedial technologies have been applied will be presented and discussed, together with follow-up performance monitoring data. The use of these adsorptive technologies may allow more brownfields and other contaminated sites to quickly be brought to closure, while minimizing long-term risks over contaminant “rebound”.

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