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Independent Environmental Monitoring Program: McClean Lake Operation

Site name McClean Lake Operation
Licensee Orano Canada Inc.
Facility name McClean Lake Operation
Facility location Athabasca Basin region of northern Saskatchewan
Land acknowledgement The CNSC acknowledges that the McClean Lake Operation is located in northern Saskatchewan, on Treaty 10 territory (1906), and the Homeland of the Métis, and is within the traditional territories of the Denesųłiné, Cree, and Métis.
Facility description

In 1996, an operating licence was first issued to Orano’s McClean Lake Operation by the Atomic Energy Control Board (AECB), predecessor of the Canadian Nuclear Safety Commission (CNSC). Since then, the CNSC licence issued to Orano has been renewed several times. The current operating licence was renewed on July1, 2017, for 10-year term ending on June 30, 2027. Mining and milling of uranium ore from 5 open-pit mines ended incompleted in 2008. Orano developed a new mining method called Surface Access Borehole Resource Extraction (SABRE), which is suitable for mining small ore deposits. In 2021, Orano carried out test mining activities on the McClean Lake pods (small ore deposits) using SABRE technologyon the west side of the mill, followed by limited production in 2025.

Uranium ore mined at the Cigar Lake Operation is processed at the McClean Lake mill.

Environmental protection requirements In accordance with regulatory requirements under the Nuclear Safety and Control Act, all licensees of Class I nuclear facilities and uranium mines and mills must maintain a comprehensive environmental protection program to monitor and control nuclear and hazardous substances released from the facilities they own and operate. As part of every licensee’s environmental protection program, concentrations of contaminants in the environment must be determined and the potential exposure pathways to the public must be assessed and mitigated.

Our IEMP results from 2016 and 2025 are consistent with the results submitted by Orano, supporting our assessment that the licensee’s environmental protection program is effective. The results add to the body of evidence that people and the environment in the vicinity of the McClean Lake Operation are protected and that there are no anticipated health impacts from the operation of the facilities on the site.

Interactive map

View the IEMP’s interactive map and the instructions on navigating IEMP mapping.

Results

2025

The 2025 IEMP sampling plan for the McClean Lake Operation focused on radioactive nuclear and hazardous substances. A site-specific sampling plan was developed based on the licensee’s approved environmental monitoring program and our regulatory experience with the site. We endeavour to incorporate traditional Indigenous land use, values and knowledge by engaging with Indigenous Nations and communities on the sampling plan. More information on this engagement is provided in the “Indigenous Nations and communities’ participation” section.

Samples were collected by CanNorth with the assistance of 1 CNSC staff member and a community land technician from Ya’thi Néné Lands and Resources in late August and early September 2025. Surface water, fish, labrador tea leaves and blueberries were collected at a reference station (Mallen Lake) not exposed to the activities of the McClean Lake Operation, and at an exposure station (Kewen Lake) that has the potential to be impacted by the facility. Surface-water samples were also taken from the exposure stations of Telephone Lake, Sharp Lake, and Collins Creek downstream of Highway 905. Labrador tea leaves and blueberries were collected from an area close to the McClean Lake camp that is frequently used by workers. A community member provided a porcupine flesh sample that was collected near Dawn Lake, about 10 km southwest of the McClean Lake Operation.

The reference samples are taken in a location where there is likely no potential for exposure from the operations of the nuclear facility. The reference location is chosen based on distance from the operation and on meteorological data such as predominant wind direction or precipitation (for airborne releases) and water current (for waterborne releases). This allows us to collect local data that is representative of the region around the facility. The data is then compared with sampling results. This is especially important when background data, guidelines or screening levels do not exist for a certain contaminant or medium in a certain region.

Radioactivity levels (radiological contaminants) and concentrations of hazardous (non-radiological) contaminants in surface-water samples were within natural background levels Footnote 1 and below the Canadian Council of Ministers of the Environment (CCME) guidelines for the protection of aquatic life Footnote 2 and the Province of Saskatchewan’s drinking water quality standards and objectives Footnote 3.

For radiological contaminants in fish, Labrador tea, berries and porcupine, CNSC staff compared monitoring results to CNSC screening levels to ensure that human health is protected. CNSC screening levels were calculated based on conservative assumptions about ingestion of food and outdoor exposure, using CSA standard N288.1-20 Footnote 4 and International Commission on Radiological Protection (ICRP) Publication 119 Footnote 5. The screening level for each radionuclide in a particular medium (e.g., fish, Labrador tea, berries, porcupine) represents the radioactivity level that would result in a dose of 0.1 millisieverts per year (mSv/year), or one tenth of the CNSC regulatory dose limit for a member of the public of 1 mSv/year Footnote 6. The approach used by CNSC staff to calculate screening levels is similar to the World Health Organization’s approach for drinking water guidelines, where 0.1 mSv/year is also used.

Except for polonium-210 in fish, which is discussed below, the measured radioactivity levels for all radiological contaminants in fish, Labrador tea, berries and porcupine were below the CNSC screening levels for radionuclides. Therefore, these results add to the body of evidence that the consumption of water, fish, Labrador tea, berries and porcupine is not expected to result in any adverse health effects from radiological contaminants.

The measured radioactivity levels of polonium-210 in fish at both the exposure and reference stations were within the regional background range of 0.02 to 14 becquerels per kilogram (Bq/kg) fresh weight Footnote 1 and were consistent with the results from the Eastern Athabasca Regional Monitoring Program (EARMP) for the northern Saskatchewan region Footnote 7. The highest radioactivity level of polonium-210 in fish analyzed in the McClean Lake area was 2.5 Bq/kg fresh weight in a northern pike sample caught at the Kewen Lake exposure station. These levels of polonium-210 are comparable to those measured in fish at the reference station and fall within the natural background range. Therefore, the results show that radioactivity levels of polonium-210 in fish in the exposure areas were not the result of the McClean Lake Operation; instead, they are attributable to natural background radioactivity levels for the region.

CNSC screening levels were also calculated for hazardous contaminants. The CNSC screening level represents the concentration required for a representative person (adult or child) to ingest one tenth of Health Canada’s tolerable daily intake (TDI) of a hazardous contaminant from multiple food ingestion pathways, such as drinking water, fruit, vegetables and fish/meat. This adds conservatism to the assessment because it considers that the receptor could be exposed to a contaminant through multiple different exposure pathways. It is likely that only 1 or 2 pathways are predominant. A TDI is the concentration of a hazardous contaminant that is safe for daily ingestion by humans on a long-term basis. The CNSC radiological and non-radiological screening levels developed for northern Saskatchewan IEMP sampling campaigns are conservative and are calculated using ingestion rates for a regional Indigenous diet.

Except for selenium in fish, which will be discussed below, the concentration of hazardous contaminants in fish, Labrador tea, berries and porcupine were below CNSC screening levels for hazardous substances. Therefore, the IEMP results support the conclusions from the EARMP and the licensee’s monitoring programs that the country foods in the vicinity of the McClean Lake Operation are safe to eat.

The results of the IEMP show that the fish samples are below the United States Environmental Protection Agency guideline of 11.3 milligrams per kilogram (mg/kg) dry weight for selenium in fish tissue. The highest concentration of selenium in fish analyzed in the McClean Lake area was 0.63 mg/kg fresh weight or 2.74 mg/kg dry weight in a lake whitefish sample caught at the Mallen Lake reference station. A concentration of 0.63 mg/kg fresh weight in fish is equal to 29% of the selenium TDI of 2.2 mg/kg fresh weight. The selenium contribution from other ingestion pathways, including water, berries and Labrador tea, was negligible. No health effects are expected from the consumption of fish due to selenium. This is because the highest concentration of selenium in fish was less than the selenium TDI of 2.2 mg/kg fresh weight, and the selenium concentrations in all other samples analyzed (water, Labrador tea, berries) were well below the screening levels. The regional background concentration of selenium in fish ranges from 0.12 to 3.03 mg/kg fresh weight Footnote 1. The measured concentrations of selenium in fish at both the exposure and reference stations were within the regional background concentration range. The results are also consistent with the results from the EARMP for the northern Saskatchewan region Footnote 7.

2016

The 2016 IEMP sampling plan for the McClean Lake Operation focused on both radiological (nuclear) and non-radiological (hazardous) contaminants. A site-specific sampling plan was developed taking into account Orano's environmental monitoring program and the CNSC's regulatory experience with the site. In August 2016, radon, surface water, fish, blueberries and Labrador tea were collected at a reference station not exposed to activities of the McClean Lake Operation (Mallen Lake) and at an exposure station (Kewen Lake), both located outside the McClean Lake Operation site perimeter.

For radiological substances, CNSC staff compared monitoring results to CNSC's screening levels to ensure that human health and the environment are protected. CNSC screening levels are established based on conservative assumptions about the how a member of the public is exposed and using CSA standard N288.1-14, Guidelines for calculating derived release limits for radioactive material in airborne and liquid effluents for normal operation of nuclear facilities. The screening level for a particular radionuclide in a particular medium (e.g., water, air and foodstuff) represents the activity concentration that would result in a dose of 0.1 mSv per year. The approach used by CNSC staff to calculate a screening level is similar to Health Canada and World Health Organization's approach for drinking water guidelines, where 0.1 mSv per year is also used. The screening levels developed for the McClean Lake IEMP sampling campaign are conservative and based on ingestion rates for a regional Indigenous diet.

The measured radioactivity in some fish samples showed levels of polonium-210 and lead-210 that were slightly above the highly conservative CNSC's screening levels. These concentrations were identified in fish caught from both the exposure station and the reference station. The reference station is not impacted by the operation of the facility and is considered background. These levels are also within the natural background of the region and below the public dose limit of 1 mSv per year. These levels are not expected to result in any adverse health effects.

With the exception of the fish samples discussed above, the measured radioactivity in the water, fish, blueberries and Labrador tea samples were below CNSC's screening levels and are within natural background levels. Also, sampling of radon in ambient air was conducted over an one-year period.  The results show that radon in ambient air at the reference and exposure locations were within natural background levels.

For non-radiological parameters where no guidelines exist, CNSC screening levels (Toxicological Reference Values (TRV)) were calculated. The CNSC screening level represents the concentration required for a representative person (adult/child) to receive a non-radiological dose of 10% the Health Canada's tolerable daily intake (TDI) due to exposure to the contaminants from multiple food ingestion pathways, such as drinking water, fruits, vegetables and fish/meat. A TDI is a daily amount of a non-radiological substance that has been assessed as safe for humans on a long-term basis.

The concentration of selenium in fish at the exposure station is similar to those measured at the reference location and is within natural background of the region. Selenium concentrations measured in fish samples from both the exposure and reference stations were higher than the CNSC screening level.

The highest concentration of selenium in fish was analyzed at Mallen Lake (reference location) in sample ML01-F02G at 0.67 mg/kg fresh weight. The contribution from other ingestion pathways including blueberries, water and from Labrador tea was negligible. Considering that only a fraction of the TDI has been reached, and taking into account the margin of safety built into the CNSC screening levels, no adverse health effects due to selenium at these levels are expected from the public from the consumption of fish.

Concentrations of arsenic in two fish samples at the exposure station (Kewen Lake) marginally exceeded the CNSC screening level. Taking into account the margin of safety built into the CNSC screening level and the fact that only a fraction of the TDI was reached, no adverse health effects due to arsenic at these levels are expected from the consumption of fish.

With the exception of arsenic and selenium in fish flesh samples discussed above, the concentration of other non-radiological substances in fish, blueberries and Labrador tea are below the CNSC screening levels.

Concentrations of water samples analyzed, with the exception of pH, are below the CCME guidelines and within the natural background levels. The pH level in the exposure station water sample was slightly below the guideline range; however the result is within known regional background levels. The pH in this area is naturally low because of high organic acid content associated with bog drainages. There is no concern to the environment or to human health at these pH levels.Indigenous Nations and communities’ participation

Indigenous Nations and communities’ participation

We have made it a priority to ensure that IEMP sampling reflects Indigenous knowledge, land use and values where possible. In addition to conducting routine IEMP sampling activities, we seek input from local Indigenous Nations and communities on our IEMP sampling plans.

In advance of the 2025 IEMP sampling campaign around the McClean Lake Operation, emails were sent to Indigenous Nations and communities with interest in the facility to notify them of the sampling campaign and to seek input on the sampling plan. We invited suggestions for species of interest, valued components, and potential sampling locations where traditional practices and activities may take place.

In April 2025, Ya’thi Néné Lands and Resources (YNLR) submitted its comments on the draft 2025 IEMP sampling plan. YNLR interviewed community members who conduct traditional activities near the McClean Lake Operation and found that there was very little concern with the sampling plan. CNSC staff added water sampling locations at Collins Creek downstream of Highway 905, at Telephone Lake and at Sharp Lake in the final sampling plan. In the field, a community land technician from YNLR accompanied one CNSC staff member and the qualified contractor to help collect samples. This collaborative sampling approach was done in an effort to build trust, build relationships and provide more information on the CNSC’s IEMP. In addition, a local community member provided a porcupine flesh sample. We would like to thank YNLR for its collaboration.

We will continue to engage with interested Indigenous Nations and communities to ensure that IEMP sampling incorporates Indigenous knowledge, values and priorities in future sampling.

Focus on health

We review the results of public health reports and data, consider international publications, and at times conduct our own health studies to provide additional confidence that the health of people living near the McClean Lake Operation is protected. The McClean Lake Operation is in northern Saskatchewan.

While there are no specific health studies for the McClean Lake Operation, the study of Eldorado uranium workers (Port Radium and Beaverlodge) found that, overall, those workers were healthier than the general Canadian male population, except with respect to lung cancer. Lung cancer incidence and mortality rates were much higher in the early uranium workers of the mid 1900s. The risk of lung cancer increased with increased workplace radon exposure. This knowledge led to modern radiation protection regulations and measures in order to limit the doses to workers and keep radiation exposures as low as reasonably achievable. Examples of this include the use of mechanical ventilation systems to ensure the availability of fresh air in the mine, continuous monitoring of worker exposures, and the application of dose limits, which together have significantly reduced workplace radiation levels. McClean Lake Operation workers are very well protected.

The CNSC is currently conducting a Canada-wide study of uranium workers: the Canadian Uranium Workers Study (CANUWS). CANUWS encompasses approximately 90,000 Canadian uranium-industry workers, including miners, millers and processing workers. The study will look at the long-term health of workers and the relationship between workplace radiation and mortality and cancer incidence, especially at the very low radiation exposures of today’s uranium workers. This work helps ensure that radiation protection regulations protect workers.

Based on current levels of radiation exposure in the environment; exposures to people living in the area; the current scientific knowledge about the sources, effects and risks of ionizing radiation; and relevant local, provincial and federal health data, we have not observed and do not expect to observe any adverse health outcomes related to the presence of the McClean Lake Operation.

The Saskatchewan Population Health and Evaluation Research Unit, the Saskatchewan Health Authority, the Northern Inter-Tribal Health Authority (NITHA), and the Saskatchewan Cancer Agency monitor the health of the populations in northern Saskatchewan.

For additional information, please visit the following websites:

Conclusions

Our IEMP results from 2016 and 2025 are consistent with the results submitted by Orano, supporting our assessment that the licensee’s environmental protection program is effective. The results add to the body of evidence that people and the environment in the vicinity of the McClean Lake Operation are protected and that there are no anticipated health impacts from the operation of the facilities on the site.

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