Lionel Britton Park - Landscaping & Soil Risk Management Project

Lionel Britton Park is located at the northwest corner of the intersection of Fifth Avenue and O’Connor Street, at 19 Fifth Avenue in Ward 17 (Capital). The site was initially established as a municipal park in the 1970s, generally including a central play structure, swings, and a few pathways and benches. Prior to the site becoming a park, the property had been developed with six units of residential townhomes from the early 1900s until at least 1965.

According to recent environmental site assessments (ESAs), there is poor quality fill and sporadic surface soil contamination underlying portions of the park. Although the risks from exposure to these types of soil conditions are considered to be low, landscape improvements have been recommended to provide more suitable cover and play surfacing across the park with engineered wood fiber. A critical aspect of the project design will be to protect and maintain the existing amenities and mature trees within the park. Accessibility upgrades are also planned as part of the project.

A Concept Plan showing the proposed design for the landscape improvements is also attached.

The City of Ottawa has initiated a landscape project to improve the shallow soil conditions at 19 Fifth Avenue, Lionel Britton Park.

Results of Environmental Site Assessments:

• A series of Environmental Site Assessments (ESAs) were completed around the area of Sylvia Holden Park (10 Fifth Avenue) and Lionel Britton Park (19 Fifth Avenue) between 2019-2022.
• Poor quality soil/fill has been identified beneath Lionel Britton Park, where contaminants in shallow soils have been sporadically detected at concentrations exceeding the provincial soil standards.

Review & Consultation with Ottawa Public Health:

• Ottawa Public Health (OPH) has reviewed the findings from the ESAs and has no objection to Lionel Britton Park remaining open. The poor quality soil/fill does not represent an immediate or acute health risk – risk would be associated with exposure of lifetime duration.
• Although the risks from exposure to this type of soil contamination are considered to be low, there are a few conditions at Lionel Britton Park which have led the City towards soil risk management: 1) due to the tree canopy and heavy use of the site, there isn’t much continuous grass cover to create a barrier from those soils at the surface of the park; and 2) the primary users of the site are toddler-aged children who are more apt to play directly on the ground and in the dirt.

Landscape Improvements for Soil Risk Management:

• The landscape improvements will involve construction of a barrier across the surface of the park. This type of risk management measure is commonly referred to as ‘soil capping’. The soil capping would generally involve placement of hard surface over the existing poor quality soils, or putting down a geotextile fabric with new suitable cover material.
• The design for the soil capping will aim to protect and maintain the existing amenities and mature trees within the park.

Lionel Britton Park and Site History

Lionel Britton Park is located at the northwest corner of the intersection of Fifth Avenue and O’Connor Street, in Ward 17 (Capital).

The property was initially established as a municipal park in the 1970s, generally including a central play structure, swings, and a few pathways and benches. Prior to the site becoming a park, the property had been developed with six units of residential townhomes from the early 1900s until at least 1965.

Environmental Investigations Completed at the Site

A Phase I ESA is a desktop study which evaluates current and historic activities around the site to identify any potential contaminating activities (PCAs) and/or areas of potential environmental concern (APECs). The Phase II ESA is the ensuing investigation which involves drilling boreholes and/or digging test pits, installing monitoring wells, and collecting/analyzing soil and groundwater samples to check for potential contaminants.

The initial Phase I ESA for Lionel Britton Park was completed in 2019, followed by the Phase II ESA in 2021, and supplemental soil testing in 2022. Seven boreholes and three monitoring wells were advanced at the site during the Phase II ESA, along with ten more shallow soil test pits completed during the supplemental soil testing program.

The ESAs were completed on behalf of the City of Ottawa’s Environmental Remediation Unit (ERU) for general assessment purposes, and for meeting the broader goals to collect and maintain a database of environmental information for the City’s Corporate Real Estate Office. The studies provide useful information for City stakeholders about all manner of environmental considerations such as project and lifecycle planning, regulatory compliance, operational maintenance, and requirements for environmental risk assessment/management, and/or remediation.

Soil Conditions and Contaminants Found at the Site

Based on the results of the ESAs, there is poor quality fill and sporadic surface soil contamination underlying portions of the park.  The fill under the site is described in the Phase II ESA as ‘poor quality demolition fill’ consisting sand/clay mixed with brick and concrete building debris, and is attributed to being left behind from the demolition of the former residential townhomes.

The principal contaminants of concern in the soil/fill are metals (namely lead), and a class of compounds known as polycyclic aromatic hydrocarbons. These are also termed polynuclear aromatic hydrocarbons, or more commonly, PAHs. The highest concentrations of lead and PAHs were generally identified in deeper soils, to which there is little opportunity for direct contact.  Areas with PAHs higher than the provincial standards were also identified within a few of the shallower (i.e. surface) soil samples, but none of the surface samples reported any metal/lead exceedances.  

Samples of the playground sand were also collected and analyzed for contaminants of concern, where the results indicate that the playground sand is not contaminated (all results meet the provincial standards).

PAHs and Metals in Soil and its Potential Health Risk

PAHs are a group of more than 100 chemicals that are generated from the incomplete combustion of fuels, waste or other organic substances. The dominant sources of PAHs in the environment are associated with human activity and they are commonly found in older urban areas, particularly those used for industrial purposes and/or manufacturing. PAHs are contained in asphalt, crude oil, coal, coal tar pitch, creosote, vehicle exhaust and can occur throughout the environment in the air, attached to dust particles, or as solids in soil or sediment.

Metals (lead) contamination in urban soils can be attributed to a number of sources including building materials, paints, fertilizers, treated timber, aged infrastructure, vehicle emissions or other general commercial/industrial wastes.

PAHs and metals can be harmful to human health under some circumstances. Several PAH compounds are potential cancer-causing agents and benzo[a]pyrene is a known carcinogen. PAHs can also be skin irritants.

Everyone is exposed to some amounts of PAHs and metals through air, soil, household dust, food, water and various consumer/household products. In order for PAH and metal contaminated soil to become a hazard, there must be direct contact with or disturbance of the contaminated soil.  The effects of PAHs and metals will depend on the extent of exposure (duration and frequency), the amount one is exposed to (relative concentration), the nature of the exposure (via inhalation, ingestion or skin contact) along with general characteristics associated with the person being exposed (age, pre-existing health conditions, etc.). Children are more susceptible to PAH and metal exposure as they tend to play on the ground surface and may consume small amounts of soil due to frequent hand-to-mouth activities. Exposure can be reduced by ensuring children wash their hands when they come in from playing outside and prior to eating, and by discouraging them from putting their fingers or playthings in their mouths.

Under the framework of ESAs in Ontario, risk evaluations are based on assumptions used by the Ontario Ministry of the Environment, Conservation and Parks (MECP) on how people are exposed to soil in a residential and parkland setting. Risk estimates are based on the precaution-based assumption that a person is exposed to soil at the site seven days a week, 39 weeks per year (periods with snow cover are discounted), for an entire lifetime (i.e. 76 years). Understanding that the presence of contaminants exceeding the MECP standards does infer the soils may pose a long-term risk to human health, it is also important to recognize that the estimates of risk are considered conservative as they assume that a person is exposed to the contaminants present in soil daily for their entire lifetime.

City's Plan to Address the Current Soil Conditions

Although the risks from exposure to this type of soil contamination are considered to be low, City staff have observed that the ground surface at Lionel Britton Park outside of paths and playgrounds is often bare exposed soil without much continuous grass cover; which is likely attributed to the thick tree canopy over the park and heavy use of the site. Also, the primary users of the park are toddler-aged children who are more apt to play directly on the ground and in the dirt. Based on these considerations in consultation with OPH, the City will design/implement shallow landscape improvements to mitigate the opportunity for direct contact with potentially contaminated soils.

The landscape improvements will involve construction of a barrier across the surface of the park. This type of risk management measure is commonly referred to as ‘soil capping’. The soil capping would generally involve placement of hard surface (such as asphalt) over the existing poor quality soils, or putting down a geotextile fabric with new suitable cover material (such as clean soil/grass or engineered wood fiber).

Excavation and Removal of Contaminated Soils

In some cases, it may be feasible to simply excavate and dispose all of the contaminated soils and replace with new clean material (commonly referred to as ‘site remediation’). However, site remediation is a much more costly and intrusive endeavor that would involve negative impacts on the existing park. There are numerous mature trees with critical root zones covering much of the site which would need to be removed for full remediation to be achieved, and it also wouldn’t be feasible to maintain/protect the existing park amenities during a site-wide remediation.

Interference with the Normal Operations and/or Community Access to Lionel Britton Park

Other than during the period of actual construction, the existing soil conditions and design/planning for landscape improvements should not interfere with the normal operation of Lionel Britton Park. The City is tentatively planning for construction to likely occur sometime in 2025, subject to completion of consultations, detailed design and confirmation of Contractor schedules.

After Proposed Landscape Improvements 

The primary objective in the design for the soil capping will be to protect and maintain the existing amenities and mature trees within the park. Some accessibility improvements will also be integrated into the park as part of the work. A Concept Plan has been provided showing the proposed layout and improvements, with a few key details summarized below:

Surface Cover: New asphalt pathways will be constructed through the park to connect the play and seating areas. Outside of the asphalt pathways, the surface cover over the entire park will be replaced with engineered wood fiber (EWF, mulch). Timber edge terracing will be used to hold the EWF in place where there are existing berms in the southern half of the park.

Play Structure: The existing play structure will be reinstated close to its current location near the center of the park. The sand around the play structure will be replaced with EWF.

Swings: The existing swing sets will be replaced with a newer version having 3 swings (a belt swing, toddler swing, and an accessible swing) at the northeast corner of the park. The sand around the swing sets will also be replaced with EWF.

Sandbox: Given all the sand around the play structure and swings are being removed, a new accessible sandbox will be provided with access from the asphalt pathway.

Trees: All of the existing trees shown in the Concept Plan will be retained and protected during construction.  Based on review and recommendations from City’s Forestry staff, only minimal removals will be required where the tree(s) are wedged closely into the fencing at the northwest corner of the park.

Other details: Three (3) accessible benches and a picnic table will be provided for seating. The chain link fence around the site will be replaced, with a slightly modified entrance to provide improved access for City maintenance staff.

If you have further questions or concerns, please contact:

City Project Leader
David Kiar
Advisor, Environmental Remediation Unit
Corporate Real Estate Office, City of Ottawa
Tel : (613) 580-2424 ext. 23251
David.kiar@ottawa.ca

Program Manager
Erin Tait
Program Manager, Environmental Remediation Unit
Corporate Real Estate Office, City of Ottawa
erin.tait@ottawa.ca

Environmental Health Specialist
Kristen Coté
Environmental Health Specialist
Healthy Environment
Ottawa Public Health
kristen.cote@ottawa.ca

Planner, Project Manager
Mike Russett
Planner, Project Manager
City of Ottawa
Parks and Facility Planning Services
Tel : (613) 580-2424 ext. 15459
Mike.russett@ottawa.ca