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Environmental protection review report summary: Cluff Lake Project

Environmental protection review reports offer a summary of CNSC staff’s technical assessment of how effectively licensees are protecting human health and the environment in the communities where they are operating.

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About the facility

The Cluff Lake Project is owned by Orano Canada Inc. (Orano) and is located approximately 75 km south of Lake Athabasca and 15 km east of the border with the Province of Alberta. Under the current operating licence, Orano is authorized to possess, manage, and store nuclear substances that are associated with the historic uranium mine and mill operations known as the Cluff Lake Project. The Cluff Lake Project was fully decommissioned in 2018 and the site is currently accessible by Indigenous Nations and communities and members of the public for hunting, fishing, camping and harvesting. The Cluff Lake Project is located on Treaty 8 territory, the Homeland of the Métis, and is within the traditional territories of the Dene, Cree, and Métis people.

About the report

This summary highlights key areas of interest from the environmental protection review report for the Cluff Lake Project. It represents only some of the information presented in the full report.

The purpose of the report is to share CNSC staff’s findings from the review of Orano’s environmental protection measures. This includes potential risks to the environment and human health from the releases of radiological and hazardous substances when the Cluff Lake Project was in operation. The report draws on information provided by Orano and the CNSC’s technical assessments, including:

  • the results of Orano’s environmental monitoring, as reported in Cluff Lake annual compliance monitoring reports
  • Orano’s 2019 technical information document, Environmental Performance, Volume 2,Version 02 (environmental risk assessment)
  • Orano’s 2019 technical information document, Hydrogeology and Groundwater Modelling, Version 02
  • the results of the CNSC’s Independent Environmental Monitoring Program (IEMP)
  • the results of other environmental monitoring programs and health studies conducted near the Cluff Lake Project

CNSC staff are confident that the potential risks to the different components of the environment from the Cluff Lake Project will remain low to negligible in the future. Likewise, human health is not impacted by the Cluff Lake Project, such that any health outcomes would be indistiguishable from health outcomes found in similar northern Saskatchewan communities. CNSC staff have also found that Orano continues to implement and maintain effective environmental protection measures that meet regulatory requirements and adequately protect the environment and the health and safety of persons.

Environmental monitoring and assessment

There are currently no releases to the environment (that is, air or surface water) from the Cluff Lake Project. The only pathways for contaminants to enter the receiving environment are from the very slow migration (over several thousands of years) of contaminants contained within the covered tailings or covered waste rock, into groundwater, and through the subsurface environment until it enters a surface water body. For this reason, CNSC staff request that Orano include additional surface water quality monitoring stations in the long-term monitoring and maintenance program.

The CNSC’s monitoring

Under the IEMP, CNSC staff take samples – such as air, water, soil, sediment, vegetation, or local food like meat, fish or berries – from public areas near nuclear facilities. For the uranium mines and mills in northern Saskatchewan, the IEMP sampling is conducted by a qualified contractor. The samples are then tested by a third-party laboratory for contaminants related to each facility's operations including radionuclides and hazardous substances.

CNSC staff, with the assistance of a qualified contractor, conducted IEMP sampling around the Cluff Lake Project in 2017.

Most of the samples measured were below the 2017 guidelines for radon, radium-226, thorium-230, polonium-210, lead-210, arsenic, copper, lead, molybdenum, nickel, selenium, uranium, zinc, ammonia, hardness, pH and total suspended solids. There were some elevated levels of polonium-210 and selenium at different sampling locations; however, they were all within the natural background levels of the region.

Our IEMP page has more information, including detailed sampling results.

Orano’s monitoring and assessment

Atmospheric environment

During the construction, operation and active decommissioning of the uranium mine, mill and tailings management area, activities resulted in releases of nuclear and hazardous substances to the atmospheric environment. However, as the Cluff Lake Project has been decommissioned and active decommissioning activities were completed by 2006, the impact on air now and in the future is negligible.

In 2019, air quality monitoring (including monitoring of radon emanating from the site) was removed from the site-wide monitoring program because previous monitoring had demonstrated that air quality had returned to background levels.

CNSC staff reviewed Orano’s environmental risk assessment and found that ambient air quality has returned to background and is at levels that protect the environment and the health and safety of persons.

Aquatic and terrestrial environment

During the operation and decommissioning of the Cluff Lake Project site, routine releases of treated liquid effluent from the wastewater treatment plant were released to Island Lake until effluent releases ceased in October 2005 and the plant was completely decommissioned in 2013.

Orano monitors surface water because of the pathway from groundwater. Based on Orano’s submitted documentation, CNSC staff found that although there is potential for effects to some species in the aquatic and terrestrial environment that consume aquatic species, most aquatic and terrestrial species will remain protected. In addition, for those species that may be affected, potential impacts are expected to be localized and temporary. CNSC staff are confident the risk to the environment and people in the region of the Cluff Lake Project is low to negligible since the environmental modelling conducted had a high level of conservatism.

Human health

Exposures to radiological and non-radiological substances

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 CNSC’s regulations, the maximum dose limit to a member of the public is 1 millisievert (mSv) per year. This is well below levels where any measurable health effect would occur.

To calculate the effective dose to people, Orano’s 2019 environmental risk assessment looked at an adult, a child and a toddler, and assumed 23 days each year doing activities such as fishing, hunting, gathering berries and camping in the immediate project area. The people Orano modelled were also assumed to consume traditional foods collected during those 23 days for 6 months of the year, and moose throughout the entire year. The assumptions around time spent around the Cluff Lake Project are based on a 2005 workshop held for the decommissioning of the Cluff Lake Project and the consumption rates are based on the Uranium City Country Foods study, which is meant to be representative of a western northern Saskatchewan diet. Due to the nature of the long-term, slow-moving contaminants present in the Cluff Lake Project tailings, the modelling done for the human health risk assessment was done for the year 2018 until the year 7000.

The estimated radiological dose, using the assumptions above, remained well below the CNSC regulatory public dose limit of 1 mSv/year, with the high predicted total effective radiological dose being to the toddler receptor, peaking at 0.3 mSv/year in the year 4000. Adult and child receptor doses peaked at 0.1 mSv/year and 0.2 mSv/year, respectively.

For exposures to non-radiological hazardous substances, the environmental risk assessment calculated daily intakes of contaminants, assuming a diet of traditional food obtained at and near the Cluff Lake Project as described above. These consumption rates were compared to appropriate Health Canada toxicity reference values (TRVs). The daily intake rates remained below their applicable TRVs for most contaminants except for arsenic and selenium, which exceeded the TRVs. The arsenic contribution of from the Cluff Lake Project was <1%, while the selenium contribution from the Cluff Lake Project was <10%. The  remaining intake of aresenic and selenium was from their concentrations in store-bought foods. Nonetheless, these levels are safe, and form part of the general Canadian diet.

In conclusion, the estimated radiological doses are well below the annual dose limit of 1 mSv and daily intake rates of non-radiological contaminants remained below their respective TRVs. CNSC staff found that Orano’s results indicate that any radiological or hazardous substance risks to casual visitors of Cluff Lake Project site (i.e., who hunt, fish, and trap over a lifetime) pose a low to negligible risk to human health.

Health studies

Reviewing health reports and conducting health studies is an important component to ensure the health of people living near or working in nuclear facilities is protected. CNSC staff consider the most recent international reports on the health effects of radiation, 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 Cluff Lake Project.

The community health studies and reports indicate that the most common causes of death among the population of northern Saskatchewan are cancer and heart disease, alongside injuries, respiratory diseases, and diabetes.

To get a snapshot of the health of the population practicing traditional rights and/or living in the region of the Cluff Lake Project, CNSC staff looked at information and data from various sources. Based on radiation exposure and health data, CNSC staff have not observed and do not expect to observe any adverse health outcomes to northern Saskatchewan communities due to the presence of the Cluff Lake Project

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