Ottawa Children's Garden soil contamination

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The City’s Environmental Remediation Unit recently found shallow soil contamination at Robert F. Legget Park and the Ottawa Children’s Garden at 321 Main St. in Old Ottawa East. Polycyclic Aromatic Hydrocarbon (PAH) compounds were detected at concentrations exceeding provincial standards.

Although these contaminants pose a risk to human health, that possibility is based on conservative lifetime exposure limits. Health effects from exposure to PAHs usually arise only in cases of prolonged exposure.

Over the winter, the City will undertake a Phase II Environmental Site Assessment (ESA) to determine the full extent of the contamination, then develop a plan to implement appropriate risk management measures and/or remediation of the site.

The City and Ottawa Public Health do not consider the current risk to be acute or immediate, and the contaminated soil is unlikely to have a health impact on anyone unless the soil itself was ingested.


Key facts

  • Ottawa Public Health has confirmed that the soil at 321 Main St. poses no immediate risk to residents.
  • Eating fruits or vegetables from the garden over a short period of time should not cause any negative health effects.
  • When the Ottawa Children’s Garden was established in 2009, the soil underwent testing and was within the acceptable provincial levels. These provincial standards were updated in 2011, and allowed levels for most PAH compounds were decreased.
  • Soil samples taken in October 2016 revealed PAH levels exceeding the newer provincial standards.
  • The Phase II Environmental Site Assessment (ESA) will collect further information about the soil and determine the full extent of the contamination.
  • Based on the results of the Phase II ESA, the City will develop a plan to implement appropriate risk management measures and/or remediation at the property in 2017.

Questions and answers

What are Polycyclic Aromatic Hydrocarbons?
PAHs are a group of more than 100 chemicals 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  are commonly found in older urban areas, particularly those used for industrial purposes or manufacturing. PAHs are contained in asphalt, crude oil, coal, ash, coal tar pitch, creosote and vehicle exhaust. They can occur throughout the environment in the air, attached to dust particles, or as solids in soil or sediment.

Is this a public health risk for anyone anyone who has visited the park?
Given the level of PAHs found by the consultant, Ottawa Public Health does not anticipate health risks associated with acute exposure, and believes a Phase II Environmental Site Assessments is the proper next step to evaluate and address any risks associated with potential long-term exposure.

How dangerous are PAHs?
Ottawa Public Health has confirmed that there is no immediate risk to residents from this soil. Acute exposure from being at the park or working in the garden should not pose any health effects.

What if my children, my family or I have eaten fruits and vegetables from the garden?
Eating fruits or vegetables from the garden for a short period of time should not cause any negative health effects.

I'm concerned about my family's health. What can I do?
Contact your family doctor or call the Public Health Info Line at 613-580-6744, Monday and Friday between 8:30 a.m. and 4:30 p.m.

Is the whole park contaminated or just the community garden?
Testing has shown higher than normal PAH levels throughout the park and garden.

Wasn't the soil tested prior to installing the garden?
Yes, the soil was tested before the garden was established 2009. At that time, contamination was below the site condition standards established by the Province of Ontario. When the province updated its standards in 2011, the 2009 samples were still below acceptable levels with the exception of a marginal exceedance of benzo(a)pyrene at one location.

What changed, and why are we finding out about it now?
Soil testing in October-November 2016 revealed higher levels of PAHs compared to 2009, with concentrations now exceeding the current, updated provincial standards. The final report from the environmental consultant was only recently submitted to the City.

How and when did the site become contaminated?
It is unclear what has caused the increase in PAH levels. According to the consultant, the contamination may be associated with the site's previous uses (e.g. as a railway loop), or with soil imported to the park during development of the Children’s Garden.

Did construction activities along Main Street cause or contribute to the elevated PAH concentrations in the park?
Because PAHs were first identified at the site in 2009, construction activities themselves are an unlikely source of elevated PAH levels.

When and how will this be fixed?
The City is recommending a detailed Phase II Environmental Site Assessment to determine the full extent of the contamination and the most appropriate remedial/risk management measures for the site. This assessment should be completed prior to the next growing season.

I’m concerned my property is also contaminated. What should I do?
Particularly within older areas of the City, elevated concentrations of metals and/or PAHs in shallow soils are not altogether uncommon. If you are concerned, you can retain a qualified environmental consultant to carry out an assessment. Good gardening practices — wearing gardening gloves, building raised beds with clean soil, thorough washing of hands and produce, etc. — will help to mitigate any health risks associated with urban gardening.

Will Robert F. Legget Park be closed during the work?
No, the park will remain open during the assessment work.

Will the Children’s Garden be closed?
The Ottawa Children’s Garden will likley need to be closed for the 2017 growing season. The City aims to implement risk management/remedial measures in the spring/summer 2017, following completion of the site assessment.

How much will it cost to fix? Who is responsible?
Following the detailed Phase II Environmental Site Assessment, the City will have a better understanding of the remedial work required to clean up the site.

Are other community gardens contaminated?
The City recently commissioned a review of in-ground community gardens on City property. Robinson Field (including the Strathcona Heights Community Garden and Sandy Hill Community Garden), and Nanny Goat Hill Community Garden in Centretown have also been flagged to undergo more detailed Environmental Site Assessments.

Have all parks been tested?
Parks are assessed and/or tested by the City for the following reasons:

  • When staff request environmental information in support of a proposed development, change in use, potential acquisition, disposal, site plan applications, etc. For example, if a new splash pad or fieldhouse is proposed, environmental testing would be performed by the City to facilitate the development, determine soil management requirements or other environmental considerations.
  • When a recent spill, a historical record or other information flags an area of potential environmental concern (referred as an ‘APEC’) warranting further attention.

However, the Environmental Remediation Unit's goal is to conduct Environmental Site Assessments (ESAs) for all City of Ottawa Parks. This is a work in progress, to be completed based on general prioritization and budget availability.