ADAPTATION & RESILIENCE IN CONTAMINATED LANDS MANAGEMENT
11th Annual Conference (Virtual) Schedule
Day 1 – Monday, September 27 – Risk Assessment
Welcome & Introductions
Zahra Pirani, Science Advisory Board for Contaminated Sites in BC
Detailed Risk Assessments at Contaminated Sites in BC: Effective Submissions under Protocol 1
Ingrid Sorensen, M.A.Sc., BC ENV and Kirstin Webster, M.E.T., R.P. Bio, BC ENV
Local Background Concentrations in Soil and Groundwater at Contaminated Sites in BC
Steve Dankevy, M.Sc., P.Geo, BC ENV; Lavinia Zanini, M.Sc., P.Geo, BC ENV
Northern Metals Contamination Case Study: Digging Deeper
to Evaluate the Risk of Metals in Soils
Marion Houlbrook, Associated Environmental Consultants Inc., Scott Steer, MET, R.P.Bio., Steer Environmental
The presentation is a case study on an investigation program and risk assessment completed on a large residential development property in a northern community. Investigations were completed over 4 years, and identified multiple metals exceeding the applicable standards in soil and groundwater over the entire large site area. Metals included antimony, arsenic, barium, cadmium, chromium, cobalt, copper, lead, nickel, tin and zinc. Soils included naturally occurring asbestos rock, originating from an historic slide. The metals were determined to be naturally occurring, but in high enough concentrations to represent a potential human health and ecological risk. The investigations required incorporation of some less common techniques for sampling and analysis, including bioavailability analysis, vegetation analysis and attempted vertebrate sampling, in order to accurately evaluate risks at the site from elevated metals. The detailed risk assessment included evaluation of non-carcinogenic and carcinogenic risks from contaminant exposures to human receptors on each future development lot as well as the risk posed by contaminants of potential concern to terrestrial ecological receptors including soil invertebrates, plants, birds, and mammals. Challenges on the project related to the remote location, asbestos health and safety concerns, and uncooperative and concerned area residents. The presentation will include an overview of the staged approach used, hurdles that were encountered, and solutions that were implemented to serve the client’s needs.
Lucy Islands Conservatory – A Focus on Metals in Soil for the Protection of the Local Rhinoceros Auklet Population and Other Terrestrial Receptors of Concern
Andrew Wan, MET, R.P.Bio., SNC-Lavalin; Tara Kennedy, MET, P.Chem., CSAP, SNC-Lavalin;
Chris Trenholm, B.Sc, P.Ag., SNC-Lavalin
Lucy Islands was previously home to a staffed navigational Light Station and is currently designated as a conservancy that is collaboratively managed by government agencies and local First Nations. The conservancy is of cultural and archeological significance to local First Nations; providing them food, medicinal plants, and cultural items.
Decommissioned in 1988, the lighthouse building and associated infrastructure has been demolished, with various investigations conducted at the island since 2010. . Although vegetation has recolonized much of the previously developed area of the island, localized soil contamination, particularly lead, remains. Lucy Islands is inhabited by a variety of ecological receptors of concern, most notably, it is home to a globally significant (5% globally) breeding population of rhinoceros auklets.
The potential for contamination to adversely impact local Indigenous site users, recreational users, the rhinoceros auklet population, and other ecological receptors was assessed in a preliminary human health and ecological risk assessment (HHERA). The HHERA was completed using reasonable worst-case assumptions in accordance with federal guidance. Both direct (via soil contact) and indirect (via consumption of berries, seaweed, and mussels) exposures of humans to contaminants were assessed. As the ecological evaluation was preliminary, risks were characterized primarily by comparisons of mean soil concentrations to Federal guidelines protective of ecological receptors. The human evaluation did not identify unacceptable risks. Moderate to high uncertainty was identified in the ecological evaluation; of significance, relatively few soil samples were collected from an exposure unit occupied by a high concentration of auklet burrows. Due to the limited window in which this exposure unit can be accessed (to prevent auklet habitat destruction during nesting periods) the characterization of contamination was limited. Additionally, estimates of predicted risk to the auklet population from incidental soil ingestion, during burrowing, was uncertain based on unknown ingestion rates.
In 2019, through collaboration with Environment and Climate Change Canada (ECCC) wildlife scientists and First Nations, additional data including blood tissue samples (with co-located soil samples) were collected from the local auklet population to provide direct measurements of lead (and zinc) body burden at worst-case exposure areas at the Site. A significant correlation was noted between lead concentrations in soil and auklet blood tissue lead concentrations. No correlation was found between zinc concentrations in soil vs. auklet blood tissue. Despite the correlation of blood lead concentrations with soil concentrations, based on a comparison of blood tissue concentrations to toxicity reference values protective of clinical endpoints. No unacceptable risks were predicted for the rhinoceros auklet population from exposure to lead. Based on this information, the remediation of lead (and zinc) in soil was not warranted for the protection of the auklet population at the Site.
Building Specific Attenuation Factors for Vapour Intrusion Assessments
Darius Mali, M.A.Sc., P.Eng. (BC)(ON), C-NRPP, Geosyntec Consultants; Paul Nicholson, P.Eng. (ON), Geosyntec Consultants; Todd McAlary, Ph.D., P.Eng. (BC)(ON), P.G. (NC), CUT, Geosyntec Consultants
Attenuation factors are the ratio of the indoor air concentration of a volatile organic compound (VOC) divided by the subslab vapour concentration of the same chemical and are used in vapour intrusion (VI) assessments to calculate subslab, soil gas and/or groundwater screening levels from health-based indoor air screening levels. Attenuation factors can also be used to calculate indoor air concentrations that might reasonably be expected to result from measured subsurface concentrations in cases where indoor air measurements are impractical (e.g., future buildings or cases where background sources confound indoor air measurements). Protocol 22 for Contaminated Sites by the British Columbia Ministry of Environmental and Climate Change, specifies generic or default attenuation factors based on building type and distance from source. For commercial/Industrial buildings, the default subslab-to-indoor air attenuation factor is 0.02. This was based on empirical data evaluated by Health Canada and the United States Environmental Protection Agency from primarily single-family residences and would be protective for about 95% of residential buildings. However, commercial/industrial buildings generally have higher air exchange rates, and often more competent foundations and floor slabs, so this may be overly conservative for commercial/industrial buildings (likely by a factor in the range of 10 to 10,000).
Building-specific attenuation factors can be calculated using building-specific subslab and indoor air sampling and analysis, but this is time-consuming and expensive. Mathematical modelling has been an option for decades, but the most common model (Johnson and Ettinger, 1991) was not formulated for a source depth directly below the floor slab. Empirical databases for commercial/industrial buildings has been compiled by the Navy and by Geosyntec for buildings in California, but in many cases the source strength is too low to generate indoor air concentrations above background levels or laboratory reporting limits, so the database is truncated. Geosyntec was recently retained by the United States Department of Defence to perform applied research on this topic and developed, demonstrated, validated and published a method for calculating a building-specific attenuation factor based on pneumatic testing, tracer testing and a simplified mathematical model with only five parameters: the transmissivity of material below the floor slab, the leakance of air across the floor slab, the building height, the air exchange rate and a reasonably conservative value for the upper-range differential pressure across the floor slab. This presentation will summarize the various methods for deriving attenuation factors and demonstrate the simplicity and cost-effectiveness of the new pneumatic based option.
Day 2 – Tuesday, September 28th – Remediation
Welcome & Introductions
Recent Advances in the Practice of Insitu Thermal Remediation
Paul R. Hegele, P.Eng., Arcadis Canada, Inc.; Art Hildebrand, P.Eng., CSAP; Arcadis Canada, Inc.
In situ thermal remediation (ISTR) is an aggressive approach for volatile organic compound (VOC) mass removal in non-aqueous phase liquid (NAPL) source zones when excavation is impractical or expensive (e.g., beneath active facilities, at considerable depth, in sensitive areas). It is also one of the few in situ approaches that is effective in fine-grained or heterogeneous media, as well as in fractured crystalline or sedimentary bedrock. Although ISTR has been widely applied in other jurisdictions, its use in British Columbia has been limited. In this presentation, we review data compiled from over 600 ISTR projects worldwide to establish trends in the growth and maturation of several ISTR technologies, including Electrical Resistance Heating (ERH), Thermal Conduction Heating (TCH), and Steam Enhanced Extraction (SEE). We discuss (i) design philosophies reflecting the current state-of-the-practice, (ii) coupled plume management strategies that leverage gentle rises in temperature downgradient to accelerate degradation reactions, and (iii) its sustainability profile in the context of the new Sustainable Resilient Remediation (SRR) guidance released by the Interstate Technology & Regulatory Council (ITRC) in 2021. Finally, a case study is presented, which discusses performance metrics and practical considerations (e.g., thermal protection of buried utilities, maximizing vapor extraction, managing heat losses).
Control of Off Site Migration in Low Permeability Soil with an Eductor System
Francis Galbraith, B.Sc., B.ASc., P.Eng., SNC-Lavalin; Calin Nan, M.ASc., P.Eng., SNC-Lavalin
SNC-Lavalin Inc. designed and constructed an eductor extraction system to mitigate downgradient contaminant migration and remediate soil vapour and groundwater at a commercial site slated for redevelopment.
The site consists of a commercial property with several tenants, and is surrounded by commercial and residential properties. Prior site investigations identified the existence of petroleum hydrocarbon and chlorinated solvent contamination in soil vapour, soil and groundwater at the site. The chlorinated solvent contamination is related to former dry cleaning activities at the site, while the petroleum hydrocarbon contamination is related to former nearby service stations. The chlorinated solvent and petroleum hydrocarbon groundwater plumes have migrated downgradient and offsite. Soil at the site is composed of fine-grained dense tills with low hydraulic conductivity.
The project objective was to minimize downgradient contaminant migration at the site prior to eventual redevelopment of the property by extracting groundwater liquids and vapors from 17 closely-spaced wells installed along the downgradient edge of the site. 5 years after the installation and operation of the eductor system there have been many learnings and insights into the operation and performance in achieving its objectives for the mitigation and remediation of chlorinated solvents and petroleum hydrocarbons associated with the site. Results from the monitoring of groundwater conditions at the site have identified reductions in observed concentrations and degradation of the chlorinated solvent and petroleum hydrocarbons in zone of influence of the system. Experience with the operation and maintenance of the eductor system which has operated with high uptime, low maintenance, and low power consumption will also be discussed. Operation of the system was modified in 2021 to limit operation of the system when sewer capacity was limited by storm events.
Key project challenges include the following:
› Remediation in an urban setting: The continued occupation of commercial tenants at the site required a very small footprint within an existing parking lot, as well as very low noise levels, to not disturb the commercial properties and nearby residents. The eductor system was able to meet these limitations.
› Active remediation in tight soils: The low permeability till soils at the site required wells with a spacing of two metres. Due to the large number of wells, an eductor system was considered to be the most cost-effective recovery method, as it reduced equipment requirements as compared to other options.
› Regulator oversight: As the site is slated for redevelopment, it receives a high degree of regulatory oversight. It was classified as a high-risk site due to high soil vapour chlorinated solvent concentrations and the presence of dense non-aqueous phase liquid (DNAPL).
Treating Soils in Place – An Alternative to Excavation
John Sankey, P.Eng., True Blue Technologies
This presentation explores recent developments for treating contaminated soil and groundwater in place with the goal of identification of better and lower cost solutions to accomplish your clients’ objectives. The presentation will provide an overview of recent technology including thermal desorption, vapour extraction, pump and treat, bioremediation, chemical reduction or oxidation, surfactant flushing, horizontal wells, sorption and stabilization additives. The discussion will focus on the pros and cons of these various approaches and how consultants can obtain the necessary information to provide to their clients as part of the remediation option analysis.
Recent Adaptation to MDMER Regulations: Removal of Ammonia from Metal and Diamond Mine Discharge
Kareena Gill, M.Eng., E.I.T.; McCue Engineering Contractors
Mining in Canada is a foundational industry and contributes billions to our economy through taxes and spending. Mining is subject to strict environmental regulations and is gaining global recognition for ethical mining. On June 1st, 2021, amendments to the Metal Mining Effluent Regulations (MMER) under the title of Metal and Diamond Mining Effluent Regulations (MDMER) came into force. Of particular significance is the ammonia discharge limit. Several activities in a mining operation introduce ammonia to the wastewaters. Two major sources are the cyanidation of gold ore and the use of ammonium nitrate-based explosives. Degradation of cyanide and the ammonium and nitrate in the explosive residue results in the release of ammonia. Untreated ammonia in mine-contacted water is harmful to aquatic life if discharged to the environment. The presence of ammonia in fish habitats has proven to be highly toxic to aquatic life. Fish does not possess the ability to eliminate ammonia from their body and therefore accumulate it even at low concentrations in water. Salmonids, especially trout, are extremely sensitive to ammonia. The low toxicity threshold for unionized ammonia for the rainbow trout has been established to be 0.4 mg-N/L by the Canadian Council of Ministers of the Environment. To limit the risks of the negative effects of mines on fish and fish habitat, the latest criteria under MDMER impose a limit on ammonia release for end-of-pipe discharges. The discharge of unionized ammonia from mines will now be required to comply with a monthly mean concentration limit of 0.5 mg-N/L. This regulation will apply to new, existing, and re-opening mines. To treat elevated ammonia levels in mine-contacted water before discharge, existing mine water treatment systems will have to be upgraded and/or new systems designed per the new criteria for ammonia discharge.
Day 3 – Wednesday, September 28 – Sustainable Investigation & Remediation
Welcome & Introductions
Implementing Sustainable and Resilient Remediation: Challenges, Opportunities, and How to Optimize with Sustainable and Resilient Quality Objectives (SRQO’s)
Paul Favara, PE, LEED GA, Jacobs
Between 2008 and 2011, numerous documents and papers provided guidance on how to integrate sustainability into remediation projects. In 2019, members of the Sustainable Remediation Forum (SURF) prepared a white paper that assessed progress of sustainable remediation and considered how the future of sustainable remediation may evolve. In this white paper, resilient remediation was identified as an emerging frontier of sustainable remediation. Additionally, much industry work has been focused on resilient remediation, primarily through the United States Interstate Technology and Research Council’s publication of their Sustainable Resilient Remediation document in 2021. Although inherently different, sustainable remediation and resilient remediation are intrinsically linked around impact. While sustainable remediation considers the impact of a remediation site on other systems (including environment, social, and economic), resilient remediation considers the impact of an outside threat or hazard on the remediation site or system.
With all the information about sustainable and resilient remediation available, site owners and their consultants can be overwhelmed by the amount of information to be considered for their specific project.
Based on industry perspectives and experience in implementing sustainable remediation over the last decade, and the new thoughts and applications for resiliency, this presentation focuses on identifying sustainable and resilient quality objectives (SRQOs) that can help project teams frame the kind of sustainable and resilient challenges and opportunities applicable to a specific project site. SRQO’s are best developed by considering different project related questions, for example:
- Does the cleanup project produce global warming gases that can be reduced or offset?
- Do changing coastal conditions (e.g., sea level rise) impact remedy performance?
- Is the project site located in an area susceptible to severe weather or fire?
- How will the concerns of nearby communities be impacted by the cleanup?
A risk/opportunity profile can be assigned to SRQO and the SRQO’s can be evaluated in a decision tool to convey recommendations to project stakeholders. A simple decision tool is presented as a means to highlight the prioritization and comparison of SRQOs.
This presentation will provide an overview of considerations in developing SRQOs and how they can help project teams focus on the most attainable sustainable and resilient elements for their specific project. This presentation will also highlight available resources for project case studies to provide practitioners context of what has been achieved in the application of sustainable and resilient remediation.
Restorative Remediation – Using Brownfields to Bring Nature
Back into our Urban Environments
Francois Beaudoin, P.Eng., PMP, GHD
Ever since the industrial revolution, city officials and planners have tried to re-establish a balance between the work opportunities and revenue that industry and commerce can provide in cities, and the healthy living conditions which the natural environment has been providing to humans since the dawn of our civilization. Unfortunately, there is still today a significant lack of green spaces in our modern cities. On the other hand, there is no shortage of degraded, derelict land which sits idle for extended periods, often in the very hearts of our urban landscapes. In Canada, it is estimated that there are 20 000 to 30 000 brownfields awaiting redevelopment. Many of these sites have only low levels of residual contamination on much of their surface area. In this paper, the author will discuss the unexploited opportunities that lie in urban brownfields. Whether as a permanent or temporary solution, it is possible to leverage the untapped ecological potential of these sites with urban micro-forests. It has been amply demonstrated, most notably by the work of Japanese botanist Akira Mirawaki, that it is possible to quickly restore native forests on degraded soils. This new way of looking at management of contaminated land goes beyond sustainable remediation. In recent years it has become increasingly evident that simply avoiding or reducing negative impacts is no longer sufficient, that negative impacts must be reversed or compensated by positive impacts. The united nations has declared that urgent action is required to curb the loss of biodiversity and soil ecosystem degradation.
The benefits of this restorative remediation approach are many:
- Increases urban biodiversity
- Captures CO2
- Can reduce residual contaminant concentration via nature-based remediation, often referred to as Gentle Remediation Options (GRO), by using plants (phyto-), fungi (myco-) and/or micro-organisms (bio-).
- Allows water infiltration
- Acts as noise buffer
- Improves air quality
- Provides a cooling effect
- Supports research and education
- Improves health and well-being of city dwellers
- Prevents soil erosion and dust
- Provide access to green space in marginalized communities
- Can increase surrounding land value
In addition to the above-mentioned benefits, there are many financial incentives which Canadian landowners can access by creating micro-forests on their impaired properties:
- Long term cost savings on vegetation maintenance
- Positive impact on public relations, company reputation and branding
- Offset GHG emissions: one hectare (10 000 m2) can capture approximately 5 tons of GHG per year.
- Could potentially be used for habitat compensation (to offset deforestation for example)
- Access to research grants and SRED tax credits, as well as governmental reforestation program funds and support.
The Multitude of Uses for Plant Growth Promoting Bacteria in Remediation and Site Management
Elizabeth W. Murray, Ph.D., P. Biol., R.P. Bio., Earthmaster Environmental Strategies, Inc.
Plant growth promoting rhizobacteria (PGPR) help plants to grow in stressful conditions, facilitating seed germination and plant growth in contaminated and/or poor quality soil. Contaminated soil is often remediated by excavating it and disposing in a landfill facility. Treating the soil using nature-based methods is a sustainable way of remediating the contamination to conserve the soil, reduce the carbon emissions associated with hauling to a landfill or treating using other energy intensive methods, and reduce industry dependence on landfills. Earthmaster’s PEPSystems® bacteria/plant technology adds PGPR to seeds and plants, then uses the hyper-accumulation properties of the plants for salt and trace metal uptake, and the carbon consuming properties of the bacteria to breakdown petroleum hydrocarbons to non-toxic components. This system also facilitates plant growth in reclamation applications, where contamination may be left in place as a strategy for risk based site management and where sites may have naturally elevated parameters such as salinity.
This talk will review results from both laboratory and field trials to assess the applications of PGPR for remediation of salt and/or hydrocarbon contaminated soil associated with oil and gas activities. Trials involving the use of PGPR for re-vegetation in soil containing elevated salinity and extremely poor quality soil will also be discussed, and will include trials involving both native grasses as well as various species of trees as a strategy for site management. A cost benefit analysis of using PGPR enhanced revegetation and plant based remediation methods will also be discussed and the carbon sequestration of benefits of PEPSystems will be reviewed for a number of commercial scale projects.
Phytoremediation: A Green, Sustainable and Effective Approach to Site Cleanup
Cherylin Mertes, M.Sc., P.Geo (ON, Limited), Geosyntec Consultants; Ron Gestler, Geosyntec Consultants;
Darius Mali, M.A.Sc., P.Eng (ON, BC), Geosyntec Consultants
In recent years, there has been increasing desire for green and sustainable remediation technologies. When properly designed and implemented, phytoremediation can satisfy this need while also providing effective site cleanup in reasonable timeframes. By harnessing the inherent treatment capacity of plants and their associated microbial communities, successful phytoremediation applications can effectively degrade or contain a wide array of environmental pollutants in soil, groundwater and other impacted media. Following installation, these passive, solar‐powered systems require no anthropogenic energy inputs, and can effectively achieve the three key pillars of sustainability: environmental, economic and social value. Additionally, properly implemented phytoremediation systems integrate resiliency into their designs by incorporating adequate genetic diversity through appropriate plant selection and by utilizing planting strategies that consider potential future site conditions, including increasing temperatures, changing precipitation rates, and sea‐level rise.
This presentation will provide a brief overview of phytoremediation from a sustainability and resiliency perspective, summarizing how proper phytoremediation design can achieve triple‐bottom line success. Additionally, select case studies will be presented that highlight effective phytoremediation systems that achieved sustainability goals and successfully addressed impacts caused by a variety of environmental pollutants, including a contaminant of emerging concern. These systems utilized either traditional or engineered phytoremediation planting approaches to achieve site remediation objectives, under diverse hydrogeologic conditions and complex site conditions.
The Role of Field Duplicates and Field Blanks in Environmental Investigation – Improving Sustainability and Function
Will Gaherty, M.S., P.Eng., FEC, PGL Environmental Consultants;
Mark Hugdahl, B.Sc., PChem, ALS Environmental Canada
Field blanks, trip blanks and field duplicates are rarely deployed to good advantage in environmental investigation. Continued application of currently accepted practices represents “low hanging fruit” to increase the sustainability and quality of data gathering at contaminated sites.
Various types of field Quality Control (QC) samples represent at least 15% of all environmental samples, and perhaps as much as 25%. Most Canadian environmental testing programs include 10% (rounded up) field duplicates for all matrices. The absence of such samples is considered a failure to meet standard of care in environmental consulting in Canada. Some users also include travel blanks and various types of field blanks in their field sampling quality assurance programs.
Completely independent of this, laboratories typically run an additional 20+% of lab QC samples, with at least 5% duplicates, 5% blanks, 5% spikes (lab control samples), and 5% matrix spikes or reference materials, in addition to calibration standards, 2nd source verification standards, surrogates, etc. Additionally, 17025 accredited labs periodically run blind Proficiency Test (PT) samples from 3rd party providers as independent quality control.
These programs are typically set up with little awareness by the laboratory and the their client of the other’s program. In our experience, laboratories have a more focused purpose for their programs, but field QC programs are often implemented by rote. We believe many elements of current field QC programs as currently deployed just increase costs with little benefit.
Many practitioners view field QC as being primarily a check on laboratories, with some field QC types (especially blanks) being poorly designed to identify either field sampling or laboratory issues. Even good faith efforts to interpret field QC information rarely:
- Identify systematic laboratory error or bias.
- Result in rejection of data by the user. Issues are typically written off pro forma, as expected laboratory variability, sampling error, matrix variability/heterogeneity, or nugget effect, or some combination thereof.
At the same time, most environmental investigations make no formal assessment of site-specific matrix variability, and deal idiosyncratically with the variability risk of different matrices, materiality of expected variability, analysis types, and potential contaminants of concern, if they consider them at all in their sampling plans.
While all of this might have been reasonable four decades ago, we ought to revisit this use of resources, with an eye to more effective use of field quality control samples and to reduce wasted efforts. Our presentation will explore what best practices for field sampling QC might look like.
Panel Discussion: Adaptation, Resilience and Sustainability in Contaminated Lands Management
Paul Favara, Jacobs; Cherilyn Mertes, Geosyntec Consultants; Francois Beaudoin, GHD;
Elizabeth Murray, Earthmaster and Will Gaherty, PGL
Registration for the 11th Annual
Conference is now Open!