Independent Environmental Monitoring Program: Rabbit Lake Operation

2022 results

The 2022 IEMP sampling plan for the Rabbit Lake Operation focused on radioactive 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.

In late August and early September 2022, with the assistance of a CNSC staff member and a Community Land Technician from Ya’thi Néné Lands and Resources, CanNorth collected surface water and Labrador tea at a reference1 station (North shore of Collins Bay of Wollaston Lake) not exposed to the activities of the Rabbit Lake Operation and at 3 exposure stations (Hidden Bay near Horseshoe Creek Outlet, Blue Island, and Snowshoe Island). Fish samples (lake whitefish, northern pike, lake trout and walleye) were collected at Collins Bay and Hidden Bay. Blueberries samples were also collected at Collins Bay, Blue Island and Eagle Point. These samples were sent to the Saskatchewan Research Council (SRC) laboratories for testing 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 for use 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/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.

The measured radioactivity levels for all radiological contaminants in fish, Labrador tea and blueberries were below the CNSC screening levels for radionuclides. As a result, the consumption of water, fish, Labrador tea and 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. 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 Rabbit Lake Operation IEMP sampling campaign are conservative and are calculated using ingestion rates for a regional Indigenous diet.

With the exception of selenium and arsenic in fish, both of which are 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 0.24 to 0.27 mg/kg fresh weight at the Collins Bay reference station and from 0.36 to 0.77 mg/kg fresh weight at the Hidden Bay exposure station. The concentration of selenium in lake whitefish ranged from 0.29 to 0.35 mg/kg fresh weight at the Collins Bay reference station and from 0.34 to 0.64 mg/kg fresh weight at the Hidden Bay exposure station. The highest concentrations of selenium in lake trout and walleye were 0.22 and 0.25 mg/kg fresh weight. 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 Eastern Athabasca Regional Monitoring Program (EARMP) for the northern Saskatchewan region ^{Footnote 9}.

The highest concentration of selenium in fish analyzed in the Rabbit Lake Operation exposure area was 0.77 mg/kg fresh weight in a northern pike sample, caught at the Hidden Bay exposure station. A concentration of 0.77 mg/kg fresh weight in fish is equal to 35% of the selenium TDI of 2.2 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 half of the conservative CNSC screening level, and the selenium concentrations in all other samples analyzed (water, Labrador tea, blueberries) were well below the screening levels.

Furthermore, the highest concentration of selenium of 0.77 mg/kg fresh weight is equal to 3.9 mg/kg dry weight using the moisture content of the sample. This value, and all of 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 at these concentrations and that the fish is safe to eat.

The regional background concentration of arsenic in fish ranges from 0.005 to 0.1 mg/kg (milligrams per kilogram) fresh weight ^{Footnote 1}. There were two exceedances of the arsenic screening level in lake whitefish samples from the Hidden Bay exposure station. The highest concentration was 0.08 mg/kg fresh weight. A concentration of 0.08 mg/kg fresh weight in fish is equal to 4% of the arsenic TDI of 0.7 mg/kg fresh weight. The arsenic 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 arsenic. This is because the highest concentration of arsenic in fish was well below the conservative CNSC screening level, and the arsenic concentrations in all other samples analyzed (water, Labrador tea, blueberries) were well below the screening level.

¹The 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, on meteorological data such as predominant wind direction or precipitation (for atmospheric releases) and water current (for effluent discharges). This allows us to collect local data that is representative of the region around the facility. This 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.

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 2022 IEMP sampling campaign at the Rabbit Lake Operation, notification emails were sent to Indigenous Nations and communities near 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 June 2022, the Ya’thi Néné submitted their comments on the draft IEMP sampling plan. The Ya’thi Néné conducted interviews in Wollaston Lake of residents and leadership and found that there was very little concern with the draft IEMP sampling plan. The respondents identified Blue Island and Snowshoe Island as potential sampling regions. CNSC staff incorporated these two locations in the final sampling plan. The respondents also identified lake trout as a species of interest. CNSC staff added lake trout to the final sampling plan. In the field, a Community Land Technician from the Ya’thi Néné accompanied a CNSC staff member and the qualified contractor to help collect samples during the 2022 IEMP sampling campaign at the Rabbit Lake Operation. This collaborative sampling approach was done in an effort to build trust, build relationships and provide more information on the CNSC’s IEMP. We would like to thank the Ya’thi Néné for their collaboration.

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

Conclusions

Our IEMP results 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 Rabbit Lake Operation are protected, that there are no anticipated health impacts from the operation of the facilities on the site, and that the traditional foods in the vicinity of the Rabbit Lake Operation are safe to eat.