Independent Environmental Monitoring Program: McArthur River Operation

Sitename	McArthur River Operation
Licensee	Cameco Corporation (Cameco)
Facility name	McArthur River Operation
Facility location	620 km north of Saskatoon on Read Creek, within the Waterfound River watershed
Land acknowledgement	The CNSC acknowledges that the McArthur River Operation is located within Treaty 8 territory, the Homeland of the Métis, and is within the traditional territories of the Dene, Cree, and Métis peoples.
Facility description	The McArthur River Operation includes an underground mine, primary ore processing, ore slurry loading, waste management facilities, a water treatment plant, effluent storage ponds, surface freeze plants using ammonia, administration offices, a residence and warehouses. Ore is transported by truck to the Key Lake mill.
Environmental protection requirements	In accordance with regulatory requirements under the Nuclear Safety and Control Act, all licensees 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 ofevery licensee’s environmental protection program, concentrations of contaminants in the environment must be determined and the potential exposure routes to the public must be assessed.

Our Independent Environmental Monitoring Program (IEMP) results from 2021 and 2014 (last IEMP campaign in the vicinity of McArthur River) are consistent with the results submitted by Cameco, 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 McArthur River Operation are protected and that there are no anticipated health impacts from the operation of the facilities on the site. 

• Interactive map and IEMP results
• Data table McArthur River mine (download CSV – 40 Kb)
• Results: 2021 2014

2021 Results

The 2021 IEMP sampling plan for the McArthur River Operation focused on radioactive and hazardous substances (e.g., metals). 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.

In August 2021, CanNorth collected surface water, fish (lake whitefish, white sucker and northern pike), blueberries and Labrador tea samples at a reference station (Lower Read Lake) not exposed to the activities of the McArthur River Operation and at an exposure station (Little Yalowega Lake). In addition, hunters from the English River First Nation (ERFN) collected 2 moose samples: one at the road between the Key Lake Operation and the McArthur River Operation at around the 63 km marker, and one at highway 914 approximately 62 km north of Pinehouse. All sampling locations were outside the McArthur River Operation site perimeter. These samples were sent to a SRC laboratories for testing and analysis.

Moose samples collected by the ERFN were also analyzed as part of the IEMP. Please refer to the Key Lake dashboard for the results and analysis. Radioactivity levels (radiological contaminants) and concentrations of hazardous 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}. Therefore, the surface water is safe to drink relative to the parameters analyzed.

For radiological contaminants in fish, Labrador tea and blueberries, 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 N288.1-14 ^{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) represents the radioactivity level that would result in a dose of 0.1 mSv/year (millisieverts per year), or one tenth of the CNSC regulatory dose limit for a member of the public of 1 mSv per year ^{Footnote 6}. The approach used by CNSC staff to calculate screening levels is similar to the Health Canada and World Health Organization approach for drinking water guidelines ^{Footnote 7 Footnote 8}, where 0.1 mSv/year is also used.

With the exception of polonium-210 and lead-210 in fish, discussed below, the measured radioactivity levels for all radiological contaminants in fish, Labrador tea and blueberries were below the CNSC screening levels for radionuclides.
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 Bq/kg (becquerels per kilogram) fresh weight ^{Footnote 1} and were consistent with the results from the Eastern Athabasca Regional Monitoring Program (EARMP) for the northern Saskatchewan region ^{Footnote 9}. The highest radioactivity level of polonium‑210 in fish analyzed in the McArthur River study area was 1.7 Bq/kg fresh weight in a northern pike sample caught at the Lower Read Lake reference station. This level of polonium-210 is within the natural background range, bearing in mind that, by definition, a reference station is not affected by a facility’s operations. The results also show that radioactivity levels of polonium-210 in fish (maximum was 1.4 Bq/kg fresh weight) in the Little Yalowega Lake exposure area were not the result of the McArthur River Operation since they were similar to the levels detected at the reference station (Lower Read Lake). This means that they are attributable to natural background radioactivity levels for the region.

One of the measured radioactivity levels of lead-210 in fish was 3.0 Bq/kg fresh weight at the Little Yalowega Lake exposure station. This result is within the regional background range of 0.05 to 8 Bq/kg fresh weight ^{Footnote 1}. All of the other values were below the detection limit. CNSC staff performed an analysis using the ERICA Assessment tool and concluded that there is no radiological risk to fish from lead-210 at this level. The ERICA Assessment tool is a software system that determines the dose rates to biota and assesses whether there is a risk to the biota.

Consumption of fish is not expected to result in any adverse health effects from polonium-210 or lead-210 given the conservative nature of the screening levels. The radioactivity levels in water and other country foods harvested in the area were well below screening levels. The screening levels are conservative because they are based on an individual receiving a dose of 0.1 mSv/yr.

As a result, the consumption of water, fish, Labrador tea or blueberries is not expected to result in any adverse health effects from radiological contaminants.

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 10 different exposure pathways. It is likely that only 1 or 2 pathways are predominant; however, the CNSC’s assessment takes into account all 10 pathways. A TDI is the concentration of a hazardous contaminant that is safe for daily ingestion by humans on a long‑term basis. The CNSC screening levels developed for the McArthur River IEMP sampling campaign are conservative and are calculated using ingestion rates for a regional Indigenous diet.

With the exception of selenium in fish, discussed below, the concentration of hazardous contaminants in fish, blueberries and Labrador tea were below CNSC screening levels for hazardous substances.

The regional background concentration of selenium in fish ranges from 0.12 to 3.03 mg/kg (milligrams per kilogram) fresh weight ^{Footnote 1}. The concentration of selenium in northern pike ranged from 0.37 to 0.43 mg/kg fresh weight at the Lower Read Lake reference station and from 0.21 to 0.41 mg/kg fresh weight at the Little Yalowega Lake exposure station. The highest concentrations of selenium in lake whitefish and white sucker were 0.37 and 0.41 mg/kg fresh weight in Lower Read Lake (reference station) and Little Yalowega Lake (exposure station) respectively. The measured concentrations of selenium in fish at both the exposure and reference stations were within the regional background concentration range. The results also show that concentrations of selenium in fish in the exposure area of Little Yalowega Lake were not the result of the McArthur River Operation since they were similar to the levels detected at the reference station (Lower Read Lake). This means that they are attributable to natural background selenium levels for the region. The results are also consistent with the results from the EARMP for the northern Saskatchewan region [9].

The highest concentration of selenium in fish analyzed in the McArthur River study area was 0.43 mg/kg fresh weight in the lake whitefish sample, caught at the Little Yalowega Lake exposure station. A concentration of 0.43 mg/kg fresh weight in fish is 20% of the selenium TDI of 2.17 mg/kg fresh weight. The selenium contribution from other ingestion pathways, including water, blueberries 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 50% of the conservative CNSC screening level, and the selenium concentrations in all other samples analyzed (water, Labrador tea, blueberries) were well below the screening level.

For context, the selenium concentrations in fish tissue on a dry weight basis are below the United States Environmental Protection Agency’s 2016 selenium criterion for fish muscle tissue of 11.3 mg/kg dry weight. This indicates that the fish are not affected by selenium from the McArthur River Operation.

2014 Results

The 2014 IEMP sampling plan for the McArthur River Operation focused on both radiological (nuclear) and non-radiological (hazardous) contaminants. A site-specific sampling plan was developed based on Cameco's approved environmental monitoring program, CSA Group standards and the CNSC's regulatory experience with the site. In 2014, water samples were collected at a reference station upstream of the effluent discharge point, and at an exposure station downstream of the effluent discharge point, both located outside the McArthur River Operation site perimeter. View detailed sampling data.

The measured radioactivity in the samples was well below drinking water quality guidelines. No health impacts are expected at these levels.

With respect to the non-radiological analysis, the concentrations of analyzed substances in water were below the Canadian Council of Ministers of the Environment's guidelines and within the natural background levels. No health or environmental impacts are expected at these levels.

To obtain the full technical IEMP report, contact us at cnsc.info.ccsn@cnsc-ccsn.gc.ca or call 613-995-5894 or 1-800-668-5284 (in Canada). Please provide the name of the facility and the report year.

Indigenous Nations and communities’ participation

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

In advance of the 2021 IEMP sampling campaign at the McArthur River Operation, notification emails were sent to Indigenous Nations and communities near the facility to notify them of the 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.

CNSC staff sent the draft IEMP sampling plan to and held teleconferences with ERFN to gather feedback. As part of their review process, ERFN shared the draft IEMP sampling plan with Community Elders, Leadership and Land Users. ERFN reviewed the draft sampling plan and concluded that the sampling locations and sampling media were acceptable. In their review, ERFN indicated that their community members frequently harvest moose at locations between the Key Lake and McArthur River operations. As a result, ERFN suggested to the CNSC that moose samples be included in the IEMP. CNSC staff incorporated 2 moose samples into the final sampling plan. CNSC staff will continue to engage with ERFN on the McArthur River Operation.

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

View detailed sampling data.

Conclusions

Our IEMP results from 2021 and 2014 (last IEMP campaign in the vicinity of the McArthur River Operation) are consistent with the results submitted by Cameco, 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 McArthur River Operation are protected and that there are no anticipated health impacts from the operation of the facilities on the site.