2020 FCSNW logo

Stream 10b: Innovative Approaches for Contamination in Aquatic Environments
The Randle Reef Sediment Remediation Project: Stage 2 Dredging Status Update
Paul Schiller and Dave Lawrence
Public Services and Procurement Canada
The objective of this presentation is to present an update of the Stage 2 hydraulic dredging and subaqueous thin layer capping progress for the Randle Reef polycyclic aromatic hydrocarbon contaminated sediment remediation.  

The Randle Reef Sediment Remediation Project is the planned clean-up of a severely contaminated portion of Hamilton Harbour in Lake Ontario. Randle Reef is the largest polycyclic aromatic hydrocarbon (PAH) contaminated sediment site (695,000 m3) on the Canadian side of the Great Lakes and the clean-up project consists of the construction of an engineered containment facility (ECF) as well as the dredging and placement of contaminated sediment from outside the facility into the ECF. The project consists of three stages:

- Stage 1 - Construction of the ECF;
- Stage 2 - Hydraulic dredging and subaqueous thin layer capping of the contaminated sediment outside of the ECF; and,
- Stage 3 - Capping of the ECF.

The concept for the Randle Reef Sediment Remediation Project was developed in 2003 and incremental design work and consultation was completed over the following years. Funding and partnership agreements for the project were established in 2013. Funding for the $138.9 million project is provided by multiple parties including Environment and Climate Change Canada (ECCC), the Ontario Ministry of Environment, Conservation and Parks, the Hamilton-Oshawa Port Authority, Stelco, the cities of Hamilton and Burlington and the Region of Halton.

Public Services and Procurement Canada (PSPC) tendered and awarded the Stage 1 ECF construction contract in 2015, and the work was completed in 2018. In June 2017, PSPC tendered and awarded the Stage 2 dredging contract to the joint venture of Milestone Environmental Contracting from Ottawa, Ontario, and Fraser River Pile & Dredge from New Westminster, British Columbia. A service contract was awarded in 2018 to Riggs Engineering from London, Ontario, for Stage 2 construction, contract administration and resident site services.

Stage 2 site preparations began in the fall of 2017 with equipment mobilization in 2018. A custom-built hydraulic cutter suction dredge has been manufactured for the project, and a temporary water treatment facility with a capacity of 680 m3/hr has been set up to treat the dredging decant water. Dredging began in 2019 and is scheduled to be completed along with the thin layer capping in 2020.

This presentation will provide background on the Randle Reef Sediment Remediation Project, and report on the progress and status of the Stage 2 dredging contract including turbidity and debris management, dredge production rates and water treatment.

Paul Schiller, Senior Environmental Specialist, Environmental Services and Contaminated Sites, Ontario Region, Public Services and Procurement Canada
Paul Schiller is a Senior Environmental Specialist with the Environmental Services and Contaminated Sites directorate of Public Services and Procurement Canada (PSPC), Ontario Region. He has been working with PSPC for five years and is currently the Deputy Project Manager on the Randle Reef Sediment Remediation project.

Waterfront Toronto – Risk Management Measures for a New River Valley
Danielle Thorson1, David Bertrand1, Howard Cumberland1, Meggen Janes2, Laura Solano3, Don Forbes2
1Geosyntec Consultants Inc.
2Waterfront Toronto
3Michael Van Valkenburgh Associates, Inc
The objective of this presentation is to provide an overview of the risk management measures designd and current construction implementation of the Waterfront Toronto Port Lands Flood Protection and Enabling Infrastructure Project.  

With funding from the City of Toronto, the Province of Ontario and the Government of Canada, Waterfront Toronto is undertaking a massive design and revitalization of the Port Lands as part of the Waterfront Toronto Port Lands Flood Protection and Enabling Infrastructure (PLFPEI) Project. The Port Lands are a 715-acre area on the shore of Lake Ontario, immediately east of downtown Toronto. The area was human-made through decades of infilling of historic wetlands and has historically been used for heavy industry. Contaminants of concern primarily include petroleum hydrocarbons and metals. Much of the area is within the flood plain of the Don River and therefore flood protection must be created before the area can be fully developed. This includes the design and construction of a new River Valley that will connect the existing Don River to Lake Ontario.

The design of environmental risk management measures (RMMs) is a key component to providing long-term environmental protection of surface water, future visitors, workers, and ecosystem components within the project area. This presentation will provide an overview of the risk management measures designe and current construction implementation. These risk management measures will include structural and non-structural concrete secant pile walls, concrete slurry walls, clay berms, a geosynthetic clay liner, a geomembrane, and a reactive (activated carbon) layer.

Danielle Thorson, Senior Engineer, Geosyntec Consultants Inc.
Danielle Thorson is a senior engineer with Geosyntec Consultants Inc. and has over 10 years of experience in environmental consulting focusing on groundwater, soil, and sediment remediation projects. She has a degree in biological engineering from the University of Guelph. Her area of expertise is focused on the integration of multiple lines of evidence for environmental site characterization and remediation purposes. This includes the reconstruction and visualization of spatially and temporally variable data. Danielle has been involved with the design of the risk management measures for the Waterfront Toronto Port Lands river valley since 2018.

From Pilot to Full-Scale Flight – The Freshwater Oil Spill Remediation Study (FOReSt): 2018 Pilot Scale Study to 2019 Full-Scale at the Experimental Lakes Area
Tanya Shanoff1 and Vince Palace2
1Stantec Consulting Limited
2International Institute for Sustainable Development-Experimental Lakes Area
The objective of this presentation is to share the results of pilot- and full-scale studies comparing non-invasive methods for remediating oil spills in freshwater shoreline environments to help develop training tools for researchers and scientists to better understand and implement remediation options in spill response scenarios.  

Environmental impacts of oil spills are a major concern for the North American public and regulators. Improving the efficiency of clean-up procedures, as well as quantifying the efficacy of non-invasive clean-up and remediation approaches under realistic field situations, is required to address knowledge gaps and build public and regulatory confidence. Stantec Consulting Ltd. has been partnering with the International Institute for Sustainable Development-Experimental Lakes Area (IISD-ELA) in pilot- and full-scale studies comparing non-invasive methods for remediating oil spills in freshwater shoreline environments. This study has been further supported by industry funding as well as Natural Sciences and Engineering Research Council of Canada and Genome Canada grants. The study is further supported by researchers from University of Calgary, University of Ottawa, University of Manitoba and Natural Resources Canada.

In 2018, diluted bitumen and conventional heavy crude oil were applied to four constructed enclosures on a pristine lake shoreline in at IISD-ELA’s facility in Northwestern Ontario to simulate oil spills. After a period of 72 hours, surface oil was removed and a monitored natural recovery (MNR) approach was implemented as a non-invasive method for degrading residual oil from the shorelines for a period of 80 days. Recovery of the shoreline and aquatic environment was assessed through chemical analysis of petroleum hydrocarbon constituents in water, sediment, soil and by measuring concentrations and effects in ecological receptors including microbial communities, periphtyon, phytoplankton and zooplankton, emergent insects, fish and benthic invertebrates. The results and learnings from the 2018 pilot-scale program were then used to design and implement the 2019 full-scale program at IISD-ELA. The 2019 full-scale deployment included construction of 18 enclosures on three different shoreline types, application of diluted bitumen to simulate spill conditions, once again leaving the oil in the enclosures for a period of 72 hours, then removal of free phase oil. Non-invasive remediation approaches utilized after initial clean-up activities included shoreline flushing, floating wetlands designed and deployed by the University of Manitoba research team, and enhanced MNA. Data is still being collected to support understanding the effects and recovery of the oiled areas in the lake. This information will be further used to complete an ecological risk assessment and one of the goals of the research is to help develop training tools for researchers and scientists to better understand and implement remediation options in spill response scenarios.

Tanya Shanoff, Senior Hydrogeologist, Stantec Consulting Limited
Tanya Shanoff is a Senior Hydrogeologist with over 20 years of experience in the fields of contaminated sites assessment, environmental emergency response and hydrogeology. She has experience in environmental site assessments, soil and groundwater remediation, risk assessment, hydrogeological investigations, organizing and implementing sampling and monitoring programs. She has acted as a Senior Technical Lead and Hydrogeologist on contaminated sites related to military bases, airports, maintenance camps/facilities, pipeline releases, landfill sites, border crossings, manufacturing sites, highways and sawmill operations.

Tanya has experience working with a variety of contaminants of concern including petroleum hydrocarbons (PHCs), per- and polyfluoroalkyl substances (PFAS), polycyclic aromatic hydrocarbons (PAHs), metals, pesticides, herbicides, and chlorinated hydrocarbons. She is well versed in the federal regulatory framework including evaluating data and developing conceptual site models using Canadian Council of Ministers of the Environment, Health Canada, Federal Interim Groundwater Quality Guidelines, as well as risk assessments within the federal regulatory regime. She has worked to provide senior guidance with respect to compiling and assessing environmental data for sites under the Federal Contaminated Sites Action Plan (FCSAP) 10-step decision making framework. Tanya has provided consulting in support to Public Services and Procurement Canada, Defence Construction Canada/Department of National Defence, Crown-Indigenous Relations and Northern Affairs Canada and for provincial, territorial and federal departments and Crown corporations, as well as helped to author FCSAP supporting documents/guidance and provided training for federal departments on FCSAP guidance/contaminated sites assessment and management.

Application of Beneficial Reuse Concepts in Contaminated Sediment Remediation Projects – A Win for All?
Matt Woltman, Ram Mohan, Tom Wang
Anchor QEA, LLP
The objective of this presentation is to discuss and demonstrate the applicability of beneficial use technologies for the management of contaminated materials at in-water remediation sites. Beneficial use can provide site improvements and cost savings to clean-up projects while also achieving remediation objectives and should be evaluated for applicability as a remediation technology during site planning and design.  

Beneficial use (BU) of dredged sediments refers to the use of natural sediments from waterways to achieve environmentally sustainable end uses. BU is a proven technical approach and has been used in the Unites States and Canada since the 1970s, with considerably more attention given to this practice since the 1990s. Several resources have been targeted for specific BU applications, including island restoration, wetland creation or restoration, shoreline stabilization, living shorelines (for marshes), and restoration or enhancement of underwater grasses, fish/shellfish habitats, and underwater reefs. However, BU for contaminated sediments is still not considered as a widely accepted reuse concept, despite its obvious sustainability and economic benefits.

Maintenance of Canadian and United States ports and waterways to set navigable depths is a national security and economic viability initiative. Likewise, under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA, also known as Superfund), as well as the Resource Conservation and Recovery Act (RCRA), the U.S. Environmental Protection Agency in the Unites States is mandated to implement clean-up of legacy contaminated sites throughout the country. One key component of most of these remedial projects is dredging, and current practice is typically to remove and haul off site, which is quite unsustainable and costly. Noteworthy ways of implementing BU for sediments include: sustainable uses toward reducing storm damage to property and infrastructure; promoting public safety and recreation; protecting, restoring, and creating aquatic ecosystem habitats; stabilizing stream systems and enhancing shorelines; supporting risk management adaptation strategies; and, reducing the cost of dredged material placement (through end uses such as construction/fill material, civic improvement projects, and other innovative uses). This presentation will provide an analysis of how BU applies in the context of remediation projects, including key considerations, site data needs, end-use facility considerations and requirements, and economic feasibility aspects. Focusing on some of the mega sites in the United States, Canada and Norway, the presentation will demonstrate why such projects need a mandatory evaluation of BU and how effective use of BU can yield to coastal resiliency for local partners, including local governments and federal agencies.

This analysis shows that BU, if implemented properly, can yield significant returns for invested dollars in terms of reduced flood damage and reconstruction costs, as well as reduced flood insurance costs. Further, data show that BU will also provide more cost-effective clean-up of legacy contaminated sites, thereby promoting economic revitalization along these zones around Canada and the United States. Results of the economic indicators will be presented.

Matt Woltman, Anchor QEA, LLP
Matt Woltman is a professional civil engineer and engineering geologist with 20 years of experience focused on development remedial designs for contaminated sediment and upland clean-up and redevelopment projects. He has served as Engineer of Record for design and implementation of recent multiple large-scale sediment remediation projects completed in Washington State and western British Columbia with total combined construction costs of over $100 million. In addition to design development, Matt also provides tender support and construction management services to clients and owners during project implementation.

Mine Tailings Mineralogy, Hydrologic and Redox Conditions Contributing to Metal Leachability on an Intertidal Beach, Toquaht Bay Campground, Barclay Sound, BC
Rob Dickin, AECOM
The objective of this presentation is to present innovative field and modelling methods for assessing chemical fate and transport of arsenic and other metals in a marine intertidal beach groundwater/porewater system on First Nation land.  

The Toquaht Bay Campground is located approximately 16 kilometres northeast of Ucluelet, BC, on the shore of Barclay Sound. During the 1960’s, ore from the Brynnor iron mine was milled north of the campground before being shipped out by sea. Fine sand wastes (tailings) were deposited along the shoreline. Later the sandy area became a provincial campground and beach.

The Toquaht Bay Campground is part of the Maa-Nulth Treaty. The treaty specifies, if and when the Maa-Nulth wish to pursue development of the campground parcel, the Province of British Columbia will investigate for potential contamination and remediation, if necessary, under the Environmental Management Act. This work described in this presentation is part of that process. The campground is owned by Toquaht Nation.

Between 2013 and 2017 environmental investigations were conducted for constituents of potential concern (COPC). Concentrations of arsenic (up to 19,200 ug/g) and cobalt (up to 2,170ug/g) were found in the tailings in the upland soil and intertidal sediment. Concentrations observed in the intertidal area significantly exceed the BC and Canadian standards. Due to the elevated concentrations, the campground was closed pending investigations and remediation to address arsenic leachability. Multiple investigations were undertaken to develop the concentrations of COPC and the conceptual site model in media across the site. Tailings samples from various depths in the uplands and intertidal zone were tested for mineralogy, sequential leachate tests and 24-hour shake flask leach tests with distilled water and seawater. Trace sulfide minerals were identified in the tailings including arsenopyrite (FeAsS) and cobaltite (CoAsS). Oxidation of these minerals is most likely the source of the arsenic and cobalt.

The conceptual site model (CSM) considered that the upper vadose tailings are exposed to dissolved oxygen in infiltrating precipitation that causes sulfide mineral oxidation and release of dissolved metals within the water table fluctuation zone. In deeper, oxygen-depleted areas below the water table, sulfide minerals are stable and metals (arsenic) release is not occurring.

Groundwater and intertidal porewater quality was sampled using conventional groundwater monitors. Shallow intertidal porewater was also sampled using mini-piezometers and push points during falling tides. Single cell and multi-cell in-situ diffusive samplers were installed in intertidal sediment and recovered a month later to get average porewater metals concentrations at depths between 0.1 and 0.4 m. Arsenic concentrations were highest in wells near the shoreline and in the intertidal zone. Daily tidal wetting and draining, combined with active groundwater discharge, provides a dynamic environment in the marine intertidal zone which appears to increase arsenic and cobalt release to porewater (possibly due to seawater induced cation and anion exchange). Arsenic and cobalt release occurs in spite of marine pH values > 7.6 and reductions in dissolved iron concentrations (likely due to precipitation of iron oxyhydroxides in this high pH, oxidizing zone).

Intertidal sediment/pore water geochemistry and associated implications for remedial option selection to mitigate arsenic contamination are discussed. Groundwater modelling and contaminant loading calculations were completed to fully understand the influence of the marine tidal environment on metal concentrations. All conceptual remedial option designs include consideration of predicted sea level rise to the year 2100 due to climate change, as requested by Toquaht Nation.

Rob Dickin, AECOM
Rob Dickin has 40 years of experience with a background in hydrogeology, contaminated sites assessment/ remediation and waste management. He is a Professional Geologist, licensed to practice in BC (since 08/1995). Rob has been a BC Contaminated Site Approved Professional (CSAP) since 2000. He has been practicing in BC/Yukon as a senior environmental professional in BC for 30 years in hydrogeology, contaminated sites assessment/ remediation, abandoned mine reclamation and waste management. He was elected as a Fellow of Geoscientists Canada in 2013.

Advantages of Passive Sampling as a Decision-Making Tool
Brent Pautler, Sandra Dworatzek, Jeff Roberts, Michael Healey, Steve Sande
The objective of this presentation is to present some of the challenges in determination of bioavailability of organic chemicals and how passive sampling can help.  

Passive sampling devices (PSDs) present numerous advantages over conventional sample collection methods for quantifying hydrophobic organic compound (HOC) availability in sediment, soil, surface water and storm water. PSDs can provide superior convenience, cost and data quality compared to conventional grab or mechanically extracted samples. A major advantage of PSDs is their property of quantifying only the freely dissolved, bioavailable, fraction while not measuring the sorbed, or non-bioavailable fraction. Measuring only bioavailable contaminants with PSDs provides a better measure of actual toxicity and mobility for environmental receptors and a lower tendency towards toxicity overestimation than conventional sampling methods.

This presentation will highlight examples where PSDs have been used in the laboratory and in the field for decision making in site investigation and remediation, including techniques and advancements that simplify and improve ease of sampling, increase data quality and lower costs. We will demonstrate how a combination of an in-situ application of peepers as PSD to analyze sediment porewater mobility of heavy metals and ex-situ testing with polyethylene PSDs for polychlorinated biphenyl (PCB) and organochlorine pesticide (OCP) porewater concentrations was applied to site investigation. A second in-situ application will highlight the use of polyethylene-based PSDs to evaluate depth profiles of PCB porewater concentrations in sediment up to two feet below the sediment surface. A third laboratory case study will highlight the use of PSDs to evaluate the effectiveness of different levels of activated carbon to immobilize PCBs. The study reduced the remedial budget significantly by avoiding the addition of excess activated carbon amendment. The application of PSDs for in-situ field monitoring pre- and post-remedy at the site were then used to evaluate remedy performance in the field.

Sandra Dworatzek, Principal Scientist, SiREM
Sandra Dworatzek is a Principal Scientist at SiREM and has been with the company for over seventeen years. Sandra Dworatzek is an environmental microbiologist with advanced technical experience in bioaugmentation cultures and laboratory treatability studies. SiREM maintains state-of-the-art treatability, molecular testing and microbial culture production facilities in Guelph, Ontario. She currently oversees maintenance and culturing of microbial cultures that have been widely used to improve the rate and extent of bioremediation of chlorinated solvents in groundwater. As well as promoting the development of new bioaugmentation cultures for a wide range of environmental contaminants, including 1,4-dioxane, 1,2,3-trichloropropane, benzene, toluene and xylene. She provides technical oversight for laboratory treatability studies for a wide range of environmental contaminants, including halogenated organics (e.g., solvents, pesticides, etc.) and inorganics, both alone and in complex mixtures.

Lead, NaCl, Fish, Seals, Orcas, Kelp and Other Choice Four Letter Words – Integration of Environmental Compliance Measures into Marine Remediation and Construction Projects
Rebecca MacInnis1, Michael Bodman1, Shauna Davis2
1Department of National Defence
1Defence Construction Canada
The objective of this presentation is to highlight the challenges and lessons learned of integrating environmental mitigation measures into aquatic remediation and construction projects.  

Canadian Forces Base (CFB) Esquimalt is located at the south end of Vancouver Island, BC, and is the primary Pacific homeport for the Royal Canadian Navy (RCN). CFB Esquimalt is in a significant era of transformation to ensure it effectively supports the RCN into the 21st Century. There are a number of marine remediation and construction projects forming part of this transformation, including the A/B Jetty Recapitalization Project, the Small Boat Float Project and the Esquimalt Harbour Remediation Project (EHRP). These projects require significant environmental oversight to protect the marine environment.

Marine remediation and construction activities related to the A/B Jetty and Small Boat Float projects have a potentially marked impact on aquatic life including marine mammals, fish, shellfish and kelp. The EHRP is also underway to address contamination associated with historic use of the harbour. Activities included in these various projects include deconstruction of existing marine and shoreline infrastructure; dredging of contaminated sediments; remedial excavation of upland and intertidal contaminated soil; drilling/blasting/dredging of underwater bedrock outcrops; and, pile, pile cap and jetty deck installation.

A series of environmental studies and assessments were prepared for both projects to successfully obtain authorizations from Fisheries and Oceans Canada (DFO) and Transport Canada. Based on these documents and the authorizations, intensive mitigation measures have been put in place in collaboration with stakeholders and regulators to ensure the marine environment is protected. Management of water quality, management of contaminated soil and sediment, minimizing underwater noise, and offsetting for lost habitat were some of the key portions of the environmental documents submitted to DFO.

The environmental documents were based on a number of assumptions as the contractor’s methodologies and some site-specific conditions were unknown at the time when the documents were being developed. As new information was collected it became clear that some monitoring and mitigation approaches needed updating. As such, the A/B Jetty and Small Boat Float Projects are using an adaptive management approach to environmental management. This allows for modifications to monitoring and mitigation measures during remediation and construction activities, to ensure the projects comply with permit conditions as well as meet overall project objectives. Some of the key examples where adaptive management has been applied include adapting water quality criteria to background conditions, activities and sediment contamination; adjusting underwater noise thresholds to align with new research/guidance; conducting additional sampling to determine risk management strategies for residual sediment contamination; and, the conduct of fish salvage at various stages of the project implementation. A number of approaches to habitat offsetting have also been employed in Esquimalt Harbour with varying levels of success, including building artificial reefs in advance of start of construction; construction of eel grass beds; and, utilization of kelp propagation lines to promote recolonization of kelp.

Becky MacInnis, Environment Officer, Canadian Forces Base Esquimalt, Department of National Defence
Becky MacInnis, B.Sc., P.Chem., P.Ag, is an Environment Officer with the Department of National Defence (DND) at Canadian Forces Base (CFB) Esquimalt in Victoria, BC. She has over 14 years of experience in the environmental industry, the majority of which has been spent working on federal government projects both as a consultant and with Defence Construction Canada (DCC) and DND. Becky provides environmental support to Maritime Forces Pacific at CFB Esquimalt, including major capital construction projects to ensure they are completed in compliance with environmental mitigation, monitoring and regulatory requirements.

Innovative Treatment of Wood Waste Sediments Using Reactive Amendments and DGT Passive Porewater Sulphide Testing Techniques
Dan Berlin1, Dimitri Vlassopoulos1, Masekazu Kanematsu1, Joy Dunay1, Tom Wang1, Michael Waters2, Kristen Ritchot3
1Anchor QEA, LLP
2Department of National Defence
3Public Services and Procurement Canada
The objective of this presentation is to describe the innovative passive porewater DGT testing technique to measure porewater sulphide and to describe the results of in-situ treatment using iron carbonate to sequester porewater sulphides in wood waste impacted sediments for both bench- and full-scale pilot testing.  

Esquimalt Harbour has historically been used for log rafting, log storage and wood mill operations over the last 70 years, resulting in the accumulation of over 200 hectares of wood waste deposits. As wood waste decomposes, it creates a biological oxygen demand in sediments that can reduce or eliminate oxygenated zones. This can lead to a build-up of compounds such as sulphides and ammonia, which are toxic to benthic organisms at higher concentrations.

Public Services and Procurement Canada, on behalf of the Department of National Defence, has completed studies of wood waste sediments and is currently implementing a pilot project to address high sulphides in Esquimalt Harbour sediments. The studies include use of an innovative passive porewater sampling technique to quantify dissolved sulphide using the diffusive-gradient-in-thin-films (DGT) method to quickly and accurately measure porewater sulphide concentrations, which ranged from less than 1 mg/L to over 200 mg/L in harbour sediments. The DGT method is based on the reaction of sulphide with silver iodide and is becoming increasingly common as a reliable in situ technique for quantifying a range of sediment porewater constituents.

Clean-up of wood waste impacted sediments has historically involved dredging, capping, or monitored natural recovery. However, in-situ treatment amendments have the potential to oxidize or immobilize porewater sulphide. An innovative bench-scale testing program was conducted to assess the effectiveness of sand cover mixed with a range of treatment amendments to reduce bioavailable porewater sulphide concentrations in wood waste sediments. The results were used to design and implement a pilot project in Esquimalt Harbour to test the effectiveness of sand amended with iron carbonate to control sulphide concentrations and support a healthy benthic community. This presentation will describe the field investigations, bench-scale testing, design and construction of the pilot project, and initial monitoring results.

Dan Berlin, Principal Scientist, Anchor QEA, LLP
Dan Berlin is a Principal Scientist at Anchor QEA, LLP and has 19 years of professional experience managing sediment remediation projects. He is a Professional Wetland Scientist and holds a Master’s degree in Environmental Management. He specializes in designing and planning site investigations, conducting remedial options analysis and feasibility studies, and managing the design and construction of large, complex sediment remediation projects in the United States and Canada.

Management of Suspected Unexploded Ordnance in Sediment Remediation
Derek Ormerod1, Michael Bodman2, Kristen Ritchot3
1Anchor QEA, LLP
2Department of National Defence
3Public Services and Procurement Canada
The objective of this presentation is to present potential studies that could be conducted in advance of remediation to better understand the distribution of munitions and explosives of concern and unexploded ordnance and design strategies to reduce risk during construction and meet remedial objectives.  

Active and former military sites may contain munitions and explosives of concern (MEC) and unexploded ordnance (UXO) that have been discarded into waterbodies and become entrained in the sediments. These MEC and suspected UXO are typically not sources of contamination; however, they may be co-located with contamination due to other historical vessel-related activities, such as ship maintenance and repair and other industrial activities. The presence of MEC or UXO poses a challenge in the remediation of contaminated sediments, both due to the need to remove them prior to transportation of the sediment for disposal, as well as the concern for safety of workers completing the remediation efforts.

This presentation will discuss common investigation survey methods used to identify the nature and extent of MEC and UXO, such as side-scan sonar and magnetometer. These surveys may also be combined with test dredging studies and diver-based or remotely operated vehicle (ROV) surveys to document what can be observed on the surface of the sediment. These survey methods ultimately provide limited information due to the common presence of other debris that can obscure detection of MEC and UXO and the fact that only surface sediments can be observed and documented through these methods. As such, site managers are also typically required to rely on historical information and risk management strategies to determine appropriate management techniques to include during implementation of remedial actions.

This presentation will also discuss MEC and UXO management techniques that can be used during construction based on lessons learned at eight separate sediment remediation sites. Prior planning to determine appropriate requirements and coordination with agencies that may provide ultimate disposal is a critical first step in determining how to require a contractor to segregate MEC and UXO. Requirements are driven by available guidance that directs the method(s) for locating, identifying, and removing MEC and UXO. Segregation can be incorporated into design documents using a minimum material screen size or, if adequate space is available, the contractor can spread the material out in a thin lift and employ visual methods and metal detectors. Additional procedures must then be in place to address UXO and MEC that are encountered during the segregation process. This requires trained personnel to observe the segregation process, emergency procedures in place in the event live munition or UXO is discovered, and a secure magazine for temporary storage of safe-to-handle finds. Typically, the relevant military institutions in Canada and the United States would retain ownership of any MEC and UXO found and have explosive ordnance disposal teams and facilities in place to collect and ultimately dispose of MEC and UXO. These procedures can add a significant complication to remedial efforts and should be considered in development of design documents to ensure safety and compliance with landfill requirements for ultimate disposal of contaminated sediments.

Derek Ormerod, Senior Managing Engineer, Anchor QEA, LLC
Derek Ormerod, PE, is a Senior Managing Engineer at Anchor QEA, LLC, and has more than 20 years of experience with waterfront and aquatic projects, specifically remediation and restoration of previously impacted sites. Derek has managed and served as lead engineer for projects focusing on clean-up of aquatic sites, including design; impact assessment; remediation planning; delineation of impacted areas, and federal, provincial, and local permitting. He is very familiar with marine waterfront projects, working harbour operations, and remediation projects in these environments.

Questions en

fb icon   Twitter icon   linkedIn icon