This Web page has been archived on the Web.

Decommissioning of the Cluff Lake uranium mine in Saskatchewan

Petition: No. 120

Issue(s): Biological diversity, human health/environmental health, natural resources, and water

Petitioner(s): W.R. Adamson

Date Received: 25 June 2004

Status: Completed

Summary: This petition concerns the environmental assessment of a proposal to decommission the Cluff Lake uranium mining facility in northwestern Saskatchewan. The petitioner poses a number of questions about the environmental assessment report, the lack of a panel review, and mitigation measures related to contaminated lake sediment and water. 

Federal Departments Responsible for Reply: Environment Canada

Petition

June 24, 2004

Ms. Sheila Fraser,
Auditor General of Canada
240 Sparks St.,
Ottawa, ON
K1A 0G6

Commissioner of the Environment and Sustainable Development,
240 Sparks St.,
Ottawa, ON
K1A 0G6

communications@oag-bvg.gc.ca

petitions@oag-bvg.gc.ca

Dear Auditor General and Commissioner:

Re:  The Environmental Petitions Process and a Petition to the Minister of Environment Canada, the Hon. David Anderson, concerning The Cluff Lake Decommissioning Project

Context and Background

The Comprehensive Study Report issued by the CNSC and Cogema was quite deficient and unsatisfactory. It did not adequately address the issues of "environmental pollution" or the appropriate basis for "sustainable development."

It has been known for some time by citizens and various citizen groups that CNSC is more interested in facilitating and protecting the uranium industry than guarding the environment and health of the workers and public interest. The size of the investment and supposed economic returns provide undue political pressure to override the inconvenience of delays by sound environmental assessments, and the difficulties of long-term problems such as the immense wastes along the shores of Lake Athabasca, which have not been cleaned up in 50 years, and which will require billions of dollars to do so.

Moreover, the mining industry has brought undue pressure on the CEAA to speed up environmental assessments, or to by-pass them, by using the principle that "what seems to be a similar situation does not need a separate assessment." This is a dangerous principle for uranium mining where each mine is unique in situation, geology, environmental and geographic characteristics. If the current Cogema proposal serves as a prototype for future decommissionings, then we can expect serious problems for Canada, and particularly Saskatchewan, in future times.

The Comprehensive Study Report claimed that Cogema had done extensive public consultation. Yet, the public could not have given a "considered response" because even when CNSC issued its Report it did not include the primary data and test results for making future projections. Later the CNSC staff stated that anyone could have accessed the volumes of data, such as 2000A, 2000B, 2000C, 200D - but they did not tell the public they were available until the formal document came out. After that there were only a limited number of days in which citizens could make interventions. The public consultation was a farce!

When citizens did send in critique and statements of concern, the staff issued a Summary Response, and brushed them aside with arrogance and condescension, saying that the matters had been taken care of. In a Response Statement of a few pages, the staff responded 13 times with the clause, "The CSR has been reviewed by technical and scientific staff of the CNSC and other federal and provincial agencies." So, the message was "Everything is alright, and we do not need the critique of the peasants"!!

Moreover, the staff frequently made generalized statements and did not give supporting data for their position. In many instances, Cogema had not done recent field testing but took prior tests, some of them from the initial proposal for a licence, and simply projected them with computer modeling! Nature is a dynamic, changing, interrelated organism and does not go simply by computer numbering! Nature includes a lot of surprises!

Specific Issues and Concerns

1.   Radiation

(a)   The Biota

Every gram of uranium brought to the earth's surface, with 7 percent ore, brings with it some 854 becquerels of radium (a becquerel is a disintegration every second). Radium disintegrates into radon and radon daughters of Po-218, and Po-214, Po-210 which disintegrate and give off radioactivity for a half life of 1600 years.

Initially, it was thought that if protection from radiation was given to humans, then everything else would be alright. This assumption has changed in recent years. The International Atomic Energy Agency, in its document, TECDOC-1091, July 1999, has stated that care must be taken of the biota as well. Radiation, and particularly alpha radiation, has the potent power in its random floating particles to damage somatic and genetic cells in plants and creatures of the biota as well as in humans. Damage to the biota eventually will have effects upon humans in the chain of life, even upon our children and children's children.

Dr. Ward Whicker, in Radiological Health Sciences at the Colorado State University writes: "We now have a lot of new tools from molecular biology that can be used to understand ecological impacts better, and my colleagues and I have been trying hard to sell such proposals - but so far without success." (e-mail to Maisie Shiell, Oct. 8, 2002).

Neither Cogema or the CNSC have made any attempt to use these tools of molecular biology to ascertain the effects of radiation from uranium mines on the biota, although the mines exhaust dust and radon out through large fans and across the countryside.

The Comprehensive Study Report acknowledges that there are increased levels of uranium and radium in Snake Lake and Island Lake (p. 6-46), and elevated concentrations of metals and arsenic in the waters of Cluff Lake (p. 6-45).

There has been damage to the zooplankton and benthic communities in Island Lake and Snake Lake, and nickel has proved a risk to phytoplankton in Island Lake (p. 6-51), and molybdenum has proved a risk to zooplankton and northern pike in that lake also (p. 6-43). However, the staff brush aside these toxic contaminations as minuscule, and not dangerous. Yet, the radium concentrations in the waters at the outlet of Snake Lake in February of 1998 reached a maximum of 0.15 Bq/L in contrast to the normal range of 0.02 to 0.04 Bq/L. The Report does not deal with the effects of alpha radiation upon water creatures or plants in the area of the mines.

It is some 172 pages into the Report before mention is made of the cracks and spills on two different occasions where highly radioactive leach tailings containing some 6,700 Bq/g of radium Ra-226 leaked out from some of the 2,916 concrete vaults which had cracked and spilled. No mention is made of two Sask Government Inspectors' Reports (Nov. 3, 1981 and April 26, 1983) which told of very serious radioactive contamination, with a radioactivity level similar to 300 percent ore (p. 4, 1981), and the samples of liquid from under the containers yielding values for radium R-226 up to 90 Bq/L. The Inspectors stated, "Decommissioning plans for this site must take into account pad contamination." (1983, p. 5).

Yet this was not done. Cogema states that it will, in the future, run tests for gamma radiation. It hardly ever mentions alpha radiation, or how it will test for and mitigate any residual radioactivity.

(b)   Human Effects of Alpha Radiation

Cogema has done nothing to assess the health effects of alpha radiation on its workers over 22 years. Miners and mill workers are required to wear dosimeters to measure gamma radiation, and also dosimeters to measure alpha radiation. Maximum dose levels of 4 WLM (working level months) or 20 MsV (millisieverts) were set in 1975-some 29 years ago.

The problem is that the tiny highly charged particles of alpha radiation float in random fashion in the air, and are not like beams of X-ray or gamma radiation. Hence, a dosimeter may register the extent or intensity of a wave of alpha radiation, but it cannot tell if a random particle floats into the trachea and lungs of a miner or mill worker. These particles of alpha radiation are so potent that they can break chromosomes and damage somatic and genetic cells. Unfortunately, it may be 5 to 20 years before the damaged cells turn cancerous. There is a delayed action, or "latency period" which proves an unseen danger.

A number of scientific papers have been published, studying the incidence of lung cancer and deaths among uranium miners and mill workers in a retrospective approach. The American Journal of Epidemiology (1998) studied 13,570 employees of Atomic Energy of Canada Ltd., (AECL), and identified 882 male deaths and 66 female deaths. It stated: "The interest in this cohort arises because the number of subjects are classified as radiation workers with exposure to well monitored doses of low-level, low linear energy transfer radiation." (p. 1366).

A revised Study (1995) by the Ontario Ministry of Labour found that the incidence of lung cancer rates among the Elliott Lake and Bancroft Miners were threefold higher than the expected average rates of the malady (p. i). The Study makes the statement that "exposure at lower dose rates is more hazardous than exposure at higher dose rates." (p. 1)

Now the CNSC has cancelled its Saskatchewan Miners' Cohort Study (June 2004) saying that the modest number of miners and low radiation dose levels would mean that such a Study would not be "statistically accurate"! It assumed that low radiation rates would have little impact, and this without checking the facts or checking the literature. This is poor science! It contrasted the earlier higher dose rates used at Beaverlodge with the present day rates, as a cause of lung cancer rates, and ignored the Studies mentioned above. So, what is the mitigation for this delayed hazard?

More details of the Studies in Scientific Journals are available. A summation of their contents and conclusions causes one to comprehend that there is a real problem with alpha radiation.

  1. AECL Employees - by Howe et al - American Journal of Epidemiology (1988)
    • - 13,570 employees on January 1, 1950
    • - 946 deaths in 30 yrs (1950-1980) 882 males, 66 females
  2. Ontario Miners - by Finkelstein & Kusiak et al. Ontario Ministry of Labour (1995)
    • Also, Kusiak, Ritchie, Muller & Springer, British Journal of Industrial Medicine, 1993, 50: 920-928.
    • - 21,346 male miners
    • - 152 lung cancer deaths, 67.6 expected (twice the rate)
  3. Beaver Lodge Miners - by Howe, Chiarelle, & Lindsay, American Journal of Epidemiology, (1988), Vol. 128, No. 6. Also, Abbe, Howe et al. Health Physics, Vol. 60, No. 4 (April) pp. 489-495, 1991
    • - 8,487 workers
    • - 65 lung cancer deaths, 34.2 expected (twice the rate)
  4. Port Radium - by Howe, Nair, Newcombe, Miller, Burch, & Abbatt. JCNI, Vol. 79, No. 6, December, 1987
    • - 2,103 workers
    • - 57 lung cancers, 24 expected (more than twice)

So, out of the miners studied and followed, some 1,220 have died from lung cancer - practically twice the number of average or expected cases in a normal population.

2.   Sediments

The sediments in Snake Lake, the first receptor of mill affluent, and Island Lake, have been contaminated, which will affect the whole food chain among aquatic organisms. An accumulation of selenium has been found in fish tissues of northern pike and white sucker (p. 6-51).

In fact, deformities and abnormalities in fish are being observed. Back in 1998 a scientist by the name of Lemly had recommended that studies of these deformities be undertaken. Some four years later, Cogema implemented a study for assessing "the incidence of teratogenic deformities which are known to result from chronic selenium exposure." (p. 10-12) The results of any such tests have not been made public. Hence, the effects of the contamination from uranium mining continues.

It was suggested that Cogema should dredge the contaminated sediments of Snake Lake which is only one metre deep. Cogema and CNSC staff brushed aside this possibility, saying that such action would destroy much of the aquatic life in the sediments. Cogema proposes to take a "passive" approach, or a do-nothing approach to this situation, saying that the shallow lake will restore itself in 50 to 100 years! What kind of mitigation for pollution is that? This is an insult to the people and the environment of Saskatchewan. How can anyone pass over a hazard like that and call it "sustainable development"?

Cogema gained an approximate $620 million from its yellowcake from this mine, and needs to use some of these proceeds to clean up its mess. For the sake of aquatic life, it could dyke off a section of the lake for dredging, and then later let in the water and aquatic creatures, while it then focuses on a different section of the lake. This type of dyking was used at Rabbit Lake to mine uranium ore from under the shoreline of Wollaston Lake. In the City of Regina, Wascana Lake was recently (2004) dredged to a depth of 30-40 feet.

CNSC and Saskatchewan Environment need to require some real and significant mitigation of the environmental pollution from the Cluff Lake mine and mill.

Questions for the Minister of the Environment

1.   Did you read the Comprehensive Study Report of the Cluff Lake Decommissioning Project, or did you rely on your staff to read and to recommend it? Did your staff read and critique the Report with its deficiencies and problems, together with the citizen interventions? Did you and your staff simply accede to the opinions and recommendations of the CNSC?

2.   The report contains a sentence which is repeated over and over and over, like a "mantra." i.e. "the project, as described with mitigation, is not likely to cause significant adverse environmental effects." In your letter to me, and in your public announcements, why did you simply repeat the "mantra" without giving substantive reasons for your decision? What were your reasons for deciding not to give it to a Review Panel where citizens could clarify many issues, and why did you simply turn the Project over to the CNSC?

3.   As the guardian of the Environment, what would you propose as "mitigation" for the contaminated sediment and toxic water, causing abnormalities to fish, and death to aquatic creatures?

4.   What for you is "mitigation" of the effects of alpha radiation on the biota and on humans? The Comprehensive Study Report does not offer any such proposals. Yet, you judge the mitigation efforts satisfactory, when there are none!

Yours truly,

[Original signed by W.R. Adamson]

Dr. W.R. Adamson,
805 Acadia Dr.,
Saskatoon, SK
S7H 3W2

[top of page]

Minister's Response: Environment Canada

November 4, 2004

Dr. W.R. Adamson
805 Acadia Drive
Saskatoon SK
S7H 3W2

Dear Dr. Adamson:

I am writing in response to your Environmental Petition No. 120 to the Commissioner of the Environment and Sustainable Development, in which you provided background information and asked several questions about the Cluff Lake Decommissioning Project in Saskatchewan. Your petition was received on July 9.

I am pleased to enclose a detailed response which addresses the issues that fall within the Canadian Environmental Assessment Agency's and Environment Canada's mandates.

I trust that you will find this information useful.

Yours sincerely,

[Original signed by Stéphane Dion, Minister of the Environment]

Stéphane Dion


ENVIRONMENT CANADA
AND
THE CANADIAN ENVIRONMENTAL ASSESSMENT AGENCY
RESPONSE TO ENVIRONMENTAL PETITION NO. 120
UNDER THE
AUDITOR GENERAL ACT

SUBMITTED BY DR. W.R. ADAMSON

The Cluff Lake project was subject to a comprehensive study environmental assessment. A comprehensive study is required for the proposed decommissioning of a uranium mining facility on a site within the boundaries of an existing licenced uranium mining facility, since the proposal involves processing for uranium tailings management that is not authorized under the existing licence (paragraph 19(b) of the Comprehensive Study List Regulations).

The comprehensive study process is a self-directed environmental assessment process. In the context of the federal environmental assessment process, this means that the federal department(s) (responsible authorities) that make the decision about whether the federal government will support the project are responsible for considering the environmental effects of the proposed project. For this project, the responsible authority was the Canadian Nuclear Safety Commission and, as such, was responsible for ensuring that a comprehensive study was conducted and that a comprehensive study report was prepared and provided to the Minister of the Environment.

A draft comprehensive study report was prepared by the proponent. The draft report included results from technical studies and public consultations that were conducted by the proponent. The Canadian Nuclear Safety Commission, the Agency and the expert federal authorities, namely Environment Canada, Natural Resources Canada, Fisheries and Oceans Canada and Health Canada, reviewed the draft comprehensive study report. Indian and Northern Affairs Canada also reviewed and provided comments on the draft comprehensive study report. Federal and provincial technical specialists provided advice in relation to the technical aspects of the project. The review included an in-depth analysis of the potential environmental effects and the measures that were proposed to mitigate any potential adverse environmental effects. The draft comprehensive study report went through several reviews and revisions, including independent reviews by Environment Canada and the Agency, prior to it being finalized.

After receiving the final comprehensive study report, the Agency provided the public with an opportunity to provide comments on it. The Agency thoroughly reviewed all of the submissions received during the public comment period on the final comprehensive study report and subsequently asked the Canadian Nuclear Safety Commission to consider the submissions and determine if its conclusions on the significance of the environmental effects remained the same as set out in the comprehensive study report. The Canadian Nuclear Safety Commission reviewed the public comments and indicated that, after considering the public comments, the conclusions reached in the comprehensive study report remained valid.

Question 1

In your petition, you inquire as to whether the Minister had read the report or had relied on staff and whether staff had read and critiqued the report.

I can inform you that my predecessor, the Honourable David Anderson, was provided with the final comprehensive study report, a detailed analysis of the report and a summary of the public comments. These were taken into consideration by Minister Anderson, who then concluded that the decommissioning of the Cluff Lake facility did not warrant referral to a review panel and therefore referred the project back to the Canadian Nuclear Safety Commission to take action.

Question 2

In your petition, you ask why the phrase "the project as described with mitigation, is not likely to cause significant environmental effects" is used repeatedly in the comprehensive study report.

The Canadian Environmental Assessment Act requires that a conclusion be reached whether, after considering any mitigation that is considered appropriate, a project is likely to cause significant adverse environmental effects. This is a factor both for responsible authorities in the preparation of a comprehensive study report, and for the Minister of the Environment, when determining whether a panel review is required. The Minister is required to consider the comprehensive study report and the public comments filed in respect of the comprehensive study report pursuant to subsection 22(2) of the Act prior to taking a course of action under section 23 of the Act. In support of this, the Minister takes into account the implementation of any appropriate mitigation measures, the significance of the environmental effects, and public concerns regarding the project. The Minister is then required to either refer the project back to the responsible authority to take action under section 37 of the Act or refer the project to a mediator or review panel.

In the comprehensive study report, the Canadian Nuclear Safety Commission indicated that the required factors had been assessed and that, with appropriate mitigation, no significant adverse environmental effects were likely to result from the implementation of the proposed project. A more detailed discussion of the mitigation measures follows below in response to questions three and four.

Environment Canada, the Agency and other federal and provincial authorities participated in the review of the draft comprehensive study report, which included an analysis of the conclusions of the report. The public was provided with opportunities to participate in the environmental assessment process and their comments and concerns were considered. The federal and provincial authorities agreed with the conclusions put forward in the final report. My predecessor, when formulating his decision, considered the comprehensive study report, the public comments and the Canadian Nuclear Safety Commission's response to those comments.

One of the issues of concern brought forward during the public comment period on the comprehensive study report was the potential relocation of the Athabasca Chipewayan First Nation. Minister Anderson requested that the Canadian Nuclear Safety Commission contact the Athabasca Chipewayan First Nation to determine whether they intended to relocate and if so, to provide the First Nation with opportunities for participation in the next phases of the regulatory process.

Considering the thorough expert review that the project underwent as part of the comprehensive study process, Minister Anderson concluded that the project as described, with mitigation, was not likely to cause significant adverse environmental effects and that public concerns did not warrant referral to a review panel or mediator. Therefore, the project was referred back to the Canadian Nuclear Safety Commission to take action. Minister Anderson recommended that the Canadian Nuclear Safety Commission design and implement a follow-up program to determine the effectiveness of measures taken to mitigate any adverse environmental effects and to verify the accuracy of the environmental assessment of the project.

Question 3

In your petition, you ask, as the guardian of the Environment, what I would propose as "mitigation" for the contaminated sediment and toxic water, causing abnormalities to fish and death to aquatic creatures?

The Minister of the Environment relies on the environmental assessment process pursuant to the Canadian Environmental Assessment Act to provide an assessment of the potential effects of a project and suggested measures to mitigate those potential effects. The Act provides an effective means of integrating environmental factors into federal planning and decision making in support of sustainable development. Environmental assessment allows for the selection and consideration of alternatives that can contribute to sustainable development, as well as the introduction of measures that ensure negative environmental effects are avoided or minimized. In the course of this process, project-specific mitigation measures are determined to ensure that potential adverse environmental effects are not significant.

The objectives of the decommissioning activities at Cluff Lake are to remove, minimize, and control potential contaminant sources and thereby prevent any likely significant adverse environmental effects associated with the decommissioning of the mine. The criteria for the successful achievement of these objectives are the existing federal and provincial environmental guidelines for water, sediment and air quality. Where federal or provincial guidelines were not available, scientifically-sound benchmarks were derived, taking into consideration site-specific conditions.

In the comprehensive study report and related technical documentation, the potential effects on biota caused by contaminated sediment and toxic water and the measures that were proposed to mitigate these effects were addressed in considerable detail by federal and provincial technical experts, following accepted methods in environmental risk assessment.

Representative biota considered sensitive to the contaminants, or species culturally and socially valuable to the local community were assessed. Environmental effects data indicated qualitative shifts in community structure or abundance for certain biota, such as benthic invertebrates, as documented in the comprehensive study report. Death of aquatic creatures through toxic effects resulting from contamination has not been observed at the Cluff Lake project. The only notable event has been the recent occurrence of winter fish kills in the very shallow waters of Island Lake, mentioned on page 6-39 of the comprehensive study report. These kills occurred when regular inflow of fresh water into this lake from effluent treatment was halted at the end of operations. Other supplementary studies to support and guide decommissioning decisions were undertaken for key issues that arose during the comprehensive study review, such as the report on selenium toxicological impact on the early life stage of white sucker (October 2003) resident in Island Lake.

The Cluff Lake comprehensive study report indicated that selenium was present in sediments at sufficient levels to potentially produce teratogenic effects based on emerging issues in the scientific literature. As a result of regulatory review of the comprehensive study report technical documentation, COGEMA retrieved fish and sediment samples archived from the Cluff Lake area in 1998 and 1999 for selenium analysis. Selenium levels in the sediment were elevated only at Island Lake (20.3 µg /g) relative to levels of less than 0.5 µg /g at 13 other lakes, including Snake Lake, and lakes downstream of Island Lake. Snake Lake, which does not receive treated effluent, had selenium levels in sediment below the limit of detection.

Island Lake, the lake receiving treated mine effluent, has been adversely impacted by the past two decades of mining. This impact was predicted in the initial environmental assessment for the construction and operation of the mine, and in two subsequent Environmental Impact Statements. Water and sediment in Island Lake have been affected. Currently, Island Lake represents an altered, but functional, aquatic community. Molybdenum and uranium accumulations, as well as the problematic selenium and salinity concentrations, may have contributed to this change. The accumulation of heavy metals and radionuclides in the lake's sediments are seen as a long-term remediation challenge.

For Island Lake, three decommissioning alternatives were examined during the comprehensive study review for the remediation of the Lake: (1) leave problematic sediments in place and allow for natural recovery; (2) dredge sediments and dispose elsewhere; and (3) cover sediments in-place with clean material. In considering the environmental effects of each alternative relative to the likely benefits, Environment Canada agreed that the first alternative could be pursued. This was consistent with advice from Fisheries and Oceans Canada as to measures that could be undertaken to mitigate any potential adverse environmental effects associated with contaminated sediment. Fisheries and Oceans Canada was concerned that if sediments were dredged or extracted from lakes, it could cause greater impacts to the fish and biota in the lakes due to the resuspension of contaminants than if the sediment was left undisturbed. The preferred option was to temporally monitor and assess sediment quality in the lakes to assess whether they were recovering as predicted. Modeling presented in the comprehensive study report and observations elsewhere support this position.

The ecosystem in Island Lake will be monitored to verify this conclusion so that protection of the Lake and downstream waters is assured. If the results of the monitoring program indicate that mitigation is required in the future, the option of dredging sediments might be reconsidered. In addition, selenium toxicity and environmental behaviour studies are presently underway as part of the follow-up program. The details of the program will be finalized by November 2004. Cogema has made firm commitments and developed contingency plans to ensure that current effects remain restricted to only Island Lake.

The comprehensive study report documented the levels of contaminants in water in considerable detail, with further detail provided in supporting technical documents. Although there were elevated levels of certain contaminants in near-field areas as a result of the operational history of the mine, none of these levels were considered to be toxic pursuant to section 64 of the Canadian Environmental Protection Act, or acutely-lethal as defined in the Metal Mining and Effluent Regulations of the Fisheries Act.

I have been informed that gradual recovery of near-field surface waters to background levels is already occurring for key contaminants. These findings have been documented in various compliance reports submitted to the Canadian Nuclear Safety Commission on a monthly and annual basis.

Question 4

The final question you pose is what would be considered mitigation of the effects of alpha radiation on the biota and humans.

The analysis of potential effects of residual radionuclides present in the water and sediments was a major component of the environmental assessment. Effects were assessed using internationally-accepted guidelines and through modeling of effects on valued ecosystem components. Potential effects on the biota were assessed in a similar fashion to those of hazardous substances, based on the approach recommended by Environment Canada for Priority Substances. For humans, standard methods based on international guidelines promulgated by the International Commission on Radiological Protection (ICRP) were used to assess potential risks from alpha radiation. These methods are incorporated in requirements for human radiation protection in the Nuclear Safety and Control Act (Radiation Protection Regulations).

As extensively documented in the comprehensive study report, potential radiation effects relating to the decommissioning project were found to be not significant, and hence no special mitigation measures were proposed for alpha radiation. This conclusion resulted from a modelling exercise and pathway analysis conducted by the Canadian Nuclear Safety Commission, using information from water and sediment samples taken on and in the vicinity of the Cluff Lake project site. These models predict the impacts of contaminants in both water and sediments as they are taken up by aquatic macrophytes and ingested by animals. The Canadian Nuclear Safety Commission staff stated that the analysis of the potential radiological effects of the project on the environment was conducted using all relevant information, recognized methods and conservative assumptions, including the application of a relative biological effectiveness (RBE) value for alpha radiation of 40. Federal and provincial technical experts reviewed these conclusions as part of the environmental assessment process. Additional water and sediment quality readings will be taken to ensure that the assumptions used in the modeling exercise are valid.

By undertaking the natural recovery of Island Lake, the cumulative assessment indicated that the ecological risks for most aquatic biota are ameliorated within approximately 10 years post-decommissioning. For molybdenum and uranium, based on conservative benchmarks, recovery may take longer, e.g. about 50 years. Similarly, risks to sediment-dwelling organisms may decline gradually, taking up to about 100 years. For radiation, radionuclides in the water column or sediments in Island Lake watershed are not expected to have a significant effect on aquatic biota. Alpha radiation effects were addressed explicitly in that assessment.

A site-wide comprehensive radiation survey will be undertaken. It will ensure any trace terrestrial radiation sources are at safe levels for the public, and for the evolving ecosystem that will re-establish at the site. At an appropriate time, the owners of the mine will have to satisfy legal requirements for return of the site to the public. This will include the specific environmental protection requirements of the Canadian Nuclear Safety Commission for a licence to abandon.

Environment Canada will remain an active stakeholder to ensure the environment is protected at the Cluff Lake site. The Agency will be requesting information on the mitigation measures that have been implemented to date as well as the details and results of the follow-up program.