Meggen Janes Waterfront Toronto 

Toronto Port Lands and Developing Remediation Goals

www.vertexenvironmental.ca

SMART RemediationO awa, ON │ February 7, 2019

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Toronto Port Lands and Developing Remediation Goals

February 7, 2019

Agenda

• Overview

• CBRA

• Current Design

• Developing Remediation Goals• Three types summarized

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Background

• 356-hectare area, formerly largest natural wetland in Lake Ontario

• Infilled in early 1900s to support industrial growth and shipping

• Currently underutilized• Located in flood plain of Don River

Image from Google Maps 2016

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•Flood Protection Plan• Construction of a new river channel to provide flow relief• Over 1 million m3 of soil to be excavated to support river construction

• Designed to sustain regulatory flood event

• Future park areas adjacent to the new river valley

• Land areas designated for future development

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Historical Site Use

Images from http://www.blogto.com/city/2012/02/what_the_port_lands_used_to_look_like/

• Historical infilling

• Crude Oil/Petroleum Refining and Storage

• Explosives and Ammunition Manufacturing

• Metal Treatment and Fabrication

• Concrete and Cement Manufacturing

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Environmental Challenges: NAPL, PHCs, metals

Contaminant Distribution

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Community-Based Risk Assessment: Why is it needed?Developing Remediation Goals• No current environmental regulatory approval process in Ontario for a project of this nature – creating a river through a

brownfield

Selected a Community Based Risk Assessment for the large area

• Allows us to identify and evaluate the risks to human health and the environment, and develop effective measures to mitigate or remove those risks

• Allows for the development of a comprehensive strategy for treating and reusing soil within the project area – meaning that soils can be moved, treated and placed across the entire site

• Will support the creation of the new landmass around Essroc Quay, the new river mouth, flood protection landforms, municipal infrastructure and other project components

• Provides process for developing remediation goals

• Still requirement for SSRAs

Risk Management Measures (Direct Contact Caps)

• Within the CBRA, developing intervention values (IVs)

• IVs are being used to guide remediation goals for soil reused in the cap and below the cap

• IVs are risk based target values, based on component values

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Intervention Value Development

Risk Management Measure (GW to SW Control)

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Cutoff Wall Installation

• Multiple construction methods available: secant pile wall, slurry wall

• Specifications will included performance requirements during installation and post installation

• Also provides constructability benefits: minimizes dewatering and permits drier excavation

Barrier Objectives• Barrier blocks or absorbs contaminants, designing for 100 year+ 

lifespan

• What is concentration threshold at discharge from reactive barrier?• Two components: dissolved phase and potential NAPL concentrations

• If NAPL = concern then organoclay type protective layer• If dissolved phase = concern then carbon type protective layer

Barrier Assessment Point for Design Modeling

Horizontal barrier GCL + Geomembrane Reactive treatment layer (as needed)Protective cover layer

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River RMM Barrier

Discharge Threshold for Total PHCs to address NAPL- Determine what PHC concentrations results in a NAPL concern

- 12 undisturbed frozen cores, overnight shipped to Texas for NAPL Mobility Testing

- Test for potential mobility of NAPL- Test for potential for surface water sheening from NAPL left in place

• Criteria for mobile NAPL ranged from 8,000 to 16,500 ug/g of total PHC

• Surface water sheening risk if total PHC > 1,500 to 6,000 ug/g

Frozen core (core photo on left; photo under UV on right)

Surface water sheeningNAPL, mobile?

Barrier Layer

Discharge Threshold for dissolved phase• Using MECP’s GW3 (10 times Aquatic Protection 

Value)• APVs in a few cases based on old data 

(1986/1987 data) and species not anticipated at representative for future aquatic (yellow fever mosquito)

• Surrogate compounds: Naphthalene and anthracene updated to use 2012 USEPA pore water values

• What about PHCs?

Naphthalene: 6000 ug/L to 193.5 ug/LAnthracene: 0.1 ug/L to 20.73 ug/L

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Surface Water Benchmarks

Discharge Threshold for dissolved phase, PHCs

• Site specific approach important

• Bioassays completed on four species using site groundwater with initial concentrations approx. 6,400 ug/L

• Based on the testing completed to date and combining toxicity data based on both acute lethality and sublethal toxicity (i.e., immobilization), the range of benchmarks for total PHCs would be 794 to 14,400 μg/L

• Still under review with MECP

Species / TestProposed EcoBMC

Fathead Minnow Growth & Survival Test

1,200 ug/L (IC25)

Rainbow Trout Acute Lethality

>978 ug/L (LC50)

Daphnia magna Acute Lethality

794 ug/L(EC50)

Pseudokirchneriellasubcapitata (algae) Growth Inhibition Test

14,400 ug/L (IC25 * 10)

Conclusions

• CBRA and risk assessment invaluable tool for soil reuse and remediation targets

• Developed Intervention Values for soil treatment targets

• NAPL Mobility results provides a technical basis for design and barrier layer selection

• Bioassays results have high variability but has potential for development of site specific criteria

• Update thresholds with new criteria (ie. Sediment/pore water thresholds)

• ‘research’ style approach does provide basis for sound decisions

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Questions?