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Independent Environmental Monitoring Program: Port Hope Area Initiative – Port Hope Project and Port Granby Project

Publication date: April, 2021

The CNSC has issued 4 waste nuclear substance licences to Canadian Nuclear Laboratories (CNL) that fall under the Port Hope Area Initiative (PHAI) umbrella. The PHAI represents the Government of Canada’s commitment to develop and implement a safe, local, long-term solution for the management of historic low-level radioactive waste (LLRW) in the municipalities of Port Hope and Clarington, Ontario (the sites of Port Hope and Port Granby projects respectively).

The LLRW contamination found in Port Hope and Port Granby is a result of the areas’ long involvement with the nuclear industry. This legacy dates back to the 1930s with the start of radium refining activities by Eldorado Gold Mines Ltd. In the 1940s, Eldorado switched to uranium processing and became a Crown corporation (Eldorado Nuclear Limited). During those early years, wastes from radium and uranium production were stockpiled at various locations and used for fill material in construction and landscaping.

The PHAI is defined by a legal agreement signed in 2001 Footnote 1 by the Government of Canada and the municipalities of Port Hope and Clarington. In 2012, the Government of Canada, through Natural Resources Canada, made a financial commitment of $1.28 billion to implement the PHAI.

The objective of the Port Hope Project is to remediate and remove waste from the Welcome Waste Management Facility (WMF) and from residential and commercial sites containing historic LLRW and other specified industrial waste in the municipality of Port Hope. The Port Hope Project long-term waste management facility (LTWMF) is an engineered above-ground mound. It is located on the same site as the existing Welcome WMF.

The objective of the Port Granby Project is to remediate and remove historic LLRW from the existing Port Granby WMF, and to consolidate and manage this waste at a new LTWMF. The Port Granby WMF, located in the municipality of Clarington, received wastes from Eldorado Nuclear Ltd. from 1955 until 1988.

Through regular site inspections and desktop reviews, CNSC staff have concluded that CNL is carrying out work at these sites safely, in compliance with the requirements of the Nuclear Safety and Control Act (NSCA) and the respective site licences.

The results of the Independent Environmental Monitoring Program (IEMP) also support CNSC staff’s conclusion that the public and the environment around the CNL facilities are protected and that there are no expected health impacts.


Port Hope Area Initiative – Port Hope Project and Port Granby Project


Results Table

1 The < symbol indicates that a result is below the provided laboratory analytical detection limit.

2 For water samples, the results for non-radiological parameters are compared to the Canadian Water Quality Guidelines for the Protection of Aquatic Life, issued by the Canadian Council of Ministers of the Environment (CCME). Where no CCME guidelines exist, Health Canada’s Guidelines for Canadian Drinking Water Quality are used.

3 For radiological parameters, where no guidelines exist, CNSC screening levels (also known as reference levels) have been established based on conservative assumptions using CSA standard N288.1-14. The screening level for a particular radionuclide in a particular medium (e.g., water, air, food) represents the activity concentration that would result in a dose of 0.1 mSv (millisieverts) per year, a dose at which no health impacts are expected.

4 N/A - not available


Under the NSCA, licensees of nuclear facilities are required to implement an environmental monitoring program to demonstrate that the public and the environment are protected from emissions related to the facilities' nuclear activities. The results of these monitoring programs are evaluated by the CNSC to ensure compliance with applicable guidelines and limits, as set out in the regulations that govern Canada's nuclear industry.

The CNSC conducts extensive ongoing compliance verification activities of licensees’ programs. The CNSC also implements the IEMP, which is separate from but complementary to these ongoing compliance verification activities, to provide added confirmation that the public and the environment around licensed nuclear facilities are protected. The IEMP involves taking samples from public areas around the facilities to measure and analyze the amount of radioactive (nuclear) and hazardous substances in those samples. CNSC staff collect the samples and send them to the CNSC’s independent laboratory for testing and analysis. Since the implementation of the IEMP, the areas outside the Welcome and Port Granby WMF site perimeters have been sampled a number of times, in 2013, 2014, 2017 and 2019.

2019 results

CNSC staff taking a water sample from the shoreline of Lake Ontario in Port Hope

CNSC staff taking a water sample from the shoreline of Lake Ontario in Port Hope

The 2019 IEMP sampling plan for the Welcome and Port Granby WMF sites focused on both radioactive and hazardous substances [see table above]. A site-specific sampling plan was developed based on CNL’s environmental monitoring program and the CNSC’s regulatory experience with the sites. Samples, including water and sediment, were collected in publicly accessible areas outside the perimeter of the Welcome and Port Granby WMF sites.

The measured radioactivity of radium-226 in water samples was below the levels set out in federal and provincial environmental quality guidelines and standards. Similarly, the measured radioactivity of radium-226 in sediment samples was below CNSC screening levels, which are based on conservative assumptions about the exposure that would result in a dose of 0.1 mSv per year. At this dose level, which represents one-tenth of the CNSC's regulatory dose limit of 1 mSv per year for members of the public, no health impacts are expected.

In some 2019 samples of sediment and water, low levels of arsenic continued to be observed. For example, some samples collected at the Brand Creek sampling location were above guidelines for arsenic concentrations. These levels of arsenic are the result of historical releases from the Welcome WMF. Although the arsenic concentration of 6.44 mg/kg observed in 2019 is above the CCME interim sediment quality guideline of 5.9 mg/kg, it is significantly below both the maximum value of 16.23 mg/kg measured in 2013 and the CCME probable effects level for aquatic organisms (17 mg/kg). This means that arsenic levels, while above the CCME guideline, continue to decrease over time and adverse biological effects to aquatic organisms are not likely. Arsenic concentrations in sediment and water are expected to continue to decrease further (to below the CCME guidelines) following the remediation of the surrounding area and the commissioning of the LTWMF and the Wastewater Treatment Plant.

It should be noted that there are no federal or provincial environmental quality guidelines or standards for sediment uranium concentrations. Samples that were collected from Brand Creek and analyzed for uranium show values that are well below the applicable lower effects level (104.4 mg/kg, Thompson et al, 2005), Footnote 2 and only 2 (2.40 and 3.10 mg/kg) of the 14 samples collected since 2013 were marginally above the reference site values (WG08-SE05, 1.24–1.6 mg/kg). As a result, CNSC staff are confident that there is limited potential for risk to the public or environment from PHAI sediment uranium concentrations. Total dissolved solids (TDS) is composed of calcium, magnesium, sodium, potassium, carbonate, bicarbonate, chloride, sulphate and nitrate, which may impair the taste, odour or colour of water and result in excessive scaling in water pipes, water heaters, boilers and appliances. Given that the guidelines for TDS in water are an aesthetic objective Footnote 3 rather than a health-based benchmark, the measured values of TDS in water samples for 2019 do not pose any risk to public health and the environment.

The applicable CCME range for phosphorus in water for nearshore areas of Lake Ontario is 10–20 µg/L (micrograms per litre). The maximum measured phosphorus level for 2019 IEMP sampling (WG05-W06) was reported to be 14.96 µg/L, which is within the CCME range. Therefore, risk to the environment is negligible.

Past results

The 2013, 2014 and 2017 IEMP sampling plans for the Port Hope and Port Granby project sites were similar to the 2019 IEMP sampling plan, in that CNSC staff collected water and sediment samples in publicly accessible areas outside the site perimeters during those sampling years.

In 2013, 2014 and 2017, the results for radioactive substances were below federal and provincial environmental quality guidelines and standards.

The results for analyzed hazardous substances were below federal and provincial environmental quality guidelines and standards, with the exception of arsenic in water and sediment and TDS in water along Brand Creek in 2013, 2014, 2017. The slightly elevated arsenic concentrations measured in water and sediment samples along Brand Creek are consistent with monitoring results reported by the licensee. The federal guideline for TDS is an aesthetic objective only and the results measured do not pose any risk to the environment or human health. Even when arsenic and TDS concentrations are considered, the results are still indicative of levels at which no adverse health effects are expected. The elevated results for the hazardous substances reflect the influence of the historical releases and known contamination in the area. These elevated concentrations are expected to improve following the environmental clean-up activities and remediation of the surrounding area.

Focus on health

The CNSC also conducts studies to assess the health of the public near nuclear facilities. Many health studies have been performed in the area of Port Hope, Ontario, because of the historical and current presence of the nuclear industry in the community. Environmental and epidemiological studies conducted in Port Hope have consistently demonstrated that people who live near nuclear facilities are as healthy as the rest of the Canadian general population. This finding reflects the results of research studies conducted in other countries. The CNSC also reviews the results of local public health unit reports and data to provide further independent verification that the health of people in and around Port Hope and Clarington is not affected by the CNL sites. Access the CNSC’s library of health studies and third-party research.


The IEMP results provide added confirmation that the public and the environment in the vicinity of the Welcome and Port Granby WMF sites are protected and that there are no expected health impacts from CNL’s operations. These results are consistent with the results submitted by CNL, demonstrating that the licensee’s environmental protection program is working to protect the health and safety of people and the environment.

The CNSC is transitioning to an online reporting format for the IEMP. All IEMP information will be available on the online dashboard once this upgrade is complete. The CNSC recommends referencing online material for the most up-to-date and accurate data.


Footnote 1

The legal agreement was amended in 2003, 2006 and 2009.

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Footnote 2

Thompson PA, Kurias J, Mihok S. Derivation and use of sediment quality guidelines for ecological risk assessment of metals and radionuclides released to the environment from uranium mining and milling activities in Canada. Environ Monit Assess. 2005 Nov;110(1-3):71-85. doi: 10.1007/s10661-005-6291-0. PMID: 16308779.

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Footnote 3

Aesthetic objective is based on taste. TDS above 500 mg/L results in excessive scaling in water pipes, water heaters, boilers and appliances.

Return to 3 referrer

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