Language selection


Summary of environmental protection review report: Pickering Nuclear Site

Environmental protection review (EPR) reports provide CNSC staff’s evaluation of how effectively licensees are protecting human health and the environment in the communities in which they operate. The following summary highlights key areas of interest from the EPR report for the Pickering Nuclear Site (PN Site). It represents some of the information presented in the full report.

On this page:

About the facility

The PN Site includes both the Pickering Nuclear Generating Station (PNGS) and the Pickering Waste Management Facility (PWMF). The PN Site is located within the traditional and treaty territories of the Wendat, Anishinabek Nation, and the territory covered by the Williams Treaties with the Michi Saagiig and Chippewa Nation. The facility is owned and operated by the licensee, Ontario Power Generation (OPG). The PNGS (PROL 48.01/2028) and the PWMF (WFOL-W4-350.00/2028) operate under separate licences issued by the Commission to OPG. The facilities are located in the City of Pickering, within the Regional Municipality of Durham, approximately 32 kilometres east of downtown Toronto, Ontario.

About the report

The purpose of the report is to share CNSC staff’s findings from the review of OPG’s environmental protection measures and environmental compliance activities. This includes staff’s assessment of any possible environmental releases as part of normal operations and of the risks that radiological or hazardous (non-radiological) substances pose to the environment and human health. The report draws on information provided by OPG (external) and the CNSC’s technical assessments, and it includes information from 2016 to 2022 on:

  • the results of OPG’s environmental monitoring, as reported in the environmental monitoring programs (EMPs)
  • OPG’s 2022 environmental risk assessment for the PN Site
  • OPG’s preliminary decommissioning plan for the PN Site
  • the results of the CNSC’s Independent Environmental Monitoring Program
  • the results from other EMPs and/or health studies (including studies completed by other levels of government) in proximity to the PN Site

Overall, CNSC staff found that OPG continues to implement and maintain effective environmental protection measures to adequately protect the environment and the health of people living in and around the PN Site. CNSC staff found that the potential risks to the environment from any of the releases from the PN Site observed between 2016 and 2022 are similar to the risks posed by natural background levels and that any health risk is similar to that experienced by the general public in other parts of Ontario.

Environmental monitoring

In the nuclear industry, any kind of contaminant emitted by a facility is called a release. This report looks at different kinds of releases and their possible impacts on the land, air and water in the area surrounding the PN Site, as well as any potential impact on human health.

Figure 1 illustrates how a release may reach the environment through what is called an exposure pathway. In the case of the PN Site, this graphic is a simplified representation of the facility and different types of releases – such as emissions in the air or effluent in the water – and the human and ecological receptors that may interact with the releases.

Figure 1: Different potential exposure pathways through which a release from the Pickering Nuclear Site may reach the environment and humans
Conceptual exposure pathways for atmospheric, terrestrial, hydrogeological, and aquatic releases to the natural and human environment from the Pickering Nuclear Site.

The potential pathways represented in the graphic may include the following components: atmospheric release, groundwater discharge to surface water, wind erosion, airborne exposure, uptake by sediment dwelling organisms, uptake by terrestrial and aquatic wildlife species, and groundshine.

OPG must monitor its releases and measure them against pre-established limits. It then reports its results to the CNSC and other levels of government. The CNSC verifies this data by conducting reviews and inspections of OPG’s environmental protection programs.

Canadian Nuclear Safety Commission monitoring

CNSC staff conducted IEMP sampling around the PN site in 2014, 2015, 2017 and 2021. The sampling plan focused on radiological and hazardous contaminants considered in OPG’s site-wide EMP and the CNSC’s regulatory knowledge of the site.

In 2021 for the most recent campaign, CNSC staff collected air, water, soil, sand, and vegetation samples in publicly accessible areas outside the perimeter of the PN Site. Representatives from Curve Lake First Nation participated in the sampling.

Samples collected were analyzed by qualified laboratory specialists in the CNSC’s laboratory in Ottawa, using appropriate protocols. CNSC staff measured radiological and non-radiological substances in the collected samples.

The IEMP results are published on the CNSC’s IEMP web page.

Ontario Power Generation’s monitoring

Atmospheric releases

OPG monitors and controls airborne emissions that come from operations at the PN Site. Radiological emissions to air from PN Site operations include noble gases, tritium and carbon-14. Argon-41 is the predominant noble gas that is measured around the PN Site. Tritium, in the form of tritiated water vapour, is released from the heavy water system. Carbon-14 is produced from the PN Site operations.

As part of OPG’s effluent monitoring program, releases to the atmosphere are collected and are routinely analyzed for tritium, carbon-14, iodine-131, noble gases and particulates. The results are compared against derived release limits (DRLs) developed by OPG and approved by the CNSC to ensure release limits to the environment will not exceed the annual regulatory public dose limit of 1 mSv. As shown in table 1, the average radiological emissions from the PN Site remain at a very small fraction of the DRLs. As a result, CNSC staff have found that OPG continues to provide adequate protection of people and the environment.

Table 1: Annual airborne releases from the Pickering Nuclear site compared with applicable Derived Release Limits (2018 – 2022)
Parameter (Bq/a) 2018 2019 2020 2021 2022 DRLs
Tritium Oxide 6.2 × 1014 5.6 × 1014 6.5 × 1014 5.2 × 1014 4.9 × 1014 1.02 × 1017
Noble Gas 1.3 × 1014 1.3 × 1014 4.5 × 1013 1.4 × 1014 1.0 × 1014 2.66 × 1016
Iodine-131 1.2 × 107 1.4 × 107 1.0 × 107 9.7 × 106 1.1 × 107 2.82 × 1012
Particulate 7.7 × 106 5.7 × 106 5.8 × 106 1.1 × 107 1.1 × 107 4.28 × 1011
Carbon-14 3.7 × 1012 2.6 × 1012 2.3 × 1012 2.6 × 1012 2.4 × 1012 2.69 × 1015

Liquid releases

OPG routinely monitors and controls liquid effluent released from the PN Site to the environment. The PN Site is located on the north shore of Lake Ontario. The shoreline immediately adjacent to the PN Site has been altered by the construction of the condenser cooling water intake channel and the 2 water outfall channels, 1 on each side of the PN Site. The active drainage system collects active (radiological) effluent waste from the drains in reactor building, reactor auxiliary bay, irradiated fuel bay and PWMF. The active liquid waste is directed to the receiving tanks of the radioactive liquid waste management system. The activity in the liquid waste may include tritium, carbon-14, gross alpha and gross beta-gamma (such as, cesium-134, cesium-137, strontium-90, cobalt-60). The radioactive liquid waste management system uses a purification system to purify the waste to reduce radiological and non-radiological contaminants. The waste is sampled and chemically analyzed to ensure it meets radiological and non-radiological limits prior to discharge to Lake Ontario. Radioactivity monitors are on the discharge piping to automatically stop discharge flow if the detected activity is above specified limits.

As part of OPG’s EMP, samples of waterborne emissions are collected and routinely analyzed for tritium, carbon-14 and gross beta/gamma. As per table 2, the annual radiological waterborne releases from the PN Site remain a very small fraction of the licensed DRLs. There were no DRL (regulatory limit) exceedances. As a result, CNSC staff have found that OPG continues to provide adequate protection of people and the environment.

Table 2: Annual waterborne releases from the Pickering Nuclear Site compared with applicable release limits (2018 – 2022)
Parameter (Bq/a) 2018 2019 2020 2021 2022 Licence limits
Tritium Oxide 4.2 × 1014 4.3 × 1014 4.3 × 1014 4.8 × 1014 5.0 × 1014 7.87 × 1017
Gross Beta/gamma 4.3 × 1010 7.8 × 1010 3.2 × 1011 1.2 × 1011 2.0 × 1010 1.87 × 1012
Carbon-14 1.1 × 109 3.5 × 109 1.8 × 109 4.6 × 109 1.4 × 109 3.75 × 1013

Human health

Monitoring doses

When ionizing radiation penetrates the human body or an object, it deposits energy. The energy absorbed from exposure to radiation is called a dose. Under the Radiation Protection Regulations, the maximum dose limit to a member of the public is 1 mSv (millisievert) or 1,000 μSv (microsieverts) per year. This is well below levels where any measurable health effect would occur.

To calculate the effective dose to people living near the site, OPG assessed the risk to representative persons who had the potential to be the most exposed to contaminants. These include 6 potential critical groups (C2 Correctional Institution, local urban residents, local farms, local dairy farms, sport fishers, offsite industrial/commercial workers). In general, representative persons may be exposed to contaminants through 4 primary routes: dermal (skin), inhalation, incidental ingestion (soil), and ingestion of food and water.

Between 2016 and 2020, the estimated annual radiological doses for the critical receptor ranges from 1.2 to 2.1 μSv. These doses are several magnitudes lower than the regulatory annual dose limit for the public, indicating that radiological releases from the facility pose a negligible risk to human health (that is, potential risk to humans is similar to health outcomes in the general public).

Health studies

Reviewing and conducting health studies is an important component of ensuring that the health of people living near or working in nuclear facilities is protected. CNSC staff have considered the most recent international radiation epidemiology reports, the CNSC’s own information and scientific publications, as well as various community, provincial and national-level studies and reports when evaluating the health of populations living or working near the PN Site or similar facilities.

Workers and the public are protected against radiation exposures from the PN Site. The population and community health studies and reports indicate that common causes of death among the surrounding populations include ischemic heart disease, lung cancer, dementia and Alzheimer’s disease. Major health risk factors such as smoking, physical inactivity, excessive alcohol consumption, and poor diet may account for the occurrence of these diseases.

The health studies and reports presented provide a snapshot of the health of people living near the PN Site. Based on CNSC staff’s compliance monitoring of radiation and environmental protection at the facility and available health data, CNSC staff have not observed and do not expect to observe any adverse health outcomes attributable to the operation of the PN site.

Related link

For additional information, visit Environmental Protection Review Report: PN Site

Page details

Date modified: