10.2 Trends in environmental remediation of contaminated sites

Last Updated: 
May 27, 2015


This indicator measures trends in the number of contaminated sites being assessed, remediated and monitored in the NWT.

Colomac Mine Site, NWT, post-remediation
Colomac Mine Site, NWT, post-remediation,

Reported costs are those administered by the federal government. Other expenditures by mining, oil and gas companies or the GNWT are not reported.

All contaminated sites created before Devolution are managed as federal lands not transferred to the GNWT and remediation of these sites remain the responsibility of the federal government3. Details on expenditures prior to 2010 were obtained from Indian and Northern Affairs Canada, Northern Contaminated Sites Program1 and  the Federal Contaminated Sites Action Plan (2005-current)2. This indicator is under evaluation as details on costs and type of work done for each contaminated site in the NWT is no longer reported for the territory separately.

NWT focus

Work and costs related to the environmental remediation of abandoned military sites, oil and gas exploration camps and mines in northern Canada have mainly reverted to the federal government. These expenditures are significant. Changes in the number and types of contaminated sites provide insights on pressures on the environment resulting from past human activities.

Current view: status and trend

Number of contaminated sites being worked on in the NWT 2003-2010
Number of contaminated sites being worked on in the NWT 2003-2010

The number of new sites to assess and remediate should decline as sites active during the past half century ( old DEW line sites, military posts, past mining ventures) are remediated. The number of Class 1 sites being assessed increased after the 1990s when the federal government assumed responsibility for many abandoned mines and exploration sites because of private sector bankruptcies due to falling mineral prices. 

Total expenditures for all contaminated site remediation in the NWT 1990-2015
Total expenditures for all sites in the NWT. Values include Nunavut prior to 2000 inclusive, and are for NWT only after 2000. Source: INAC, NCSP. Year = fiscal year (2010 is for 2009-10).

Expenditures related to assessment, remediation and monitoring of contaminated sites in the NWT have increased during the past decade.

The main portion (more than 50%) of expenditures in the NWT are for work at two sites, the Colomac and Giant Mines--abandoned gold mines in the Taiga Shield ecozone.

Quote from the Indian and Northern Affairs Canada, Contaminated Sites, Program Performance Report 2008-2009:

(In 2008-09 and 2009-10) "The NWT experienced significant delays at a few major sites including the Colomac and Giant Mine sites. The Giant Mine Remediation Plan was instructed to undergo Environmental Assessment (EA) meaning that any activity requiring a permit cannot proceed until after the EA process. This delay has contributed to the Reigon not being able to completely spend its annual budget." 

Looking forward

Past experience and rapidly rising costs related to cleanup and remediation of industrial sites have resulted in higher standards for financial and environmental procedures at new mines and other industrial developments. These procedures include substantial environmental safety deposits and plans for progressive remediation during the lifespan of a mine. Investments in new technologies and experimental remediation programs are now the norm.

Challenges facing remediation of contaminated sites in the NWT and, elsewhere in the North, include remoteness, complexity and sizes of sites and the evolving jurisdictional landscape. Climate change has also introduced uncertainties in access and environmental changes11.

Looking around

In 2009-10, federal expenditures on remediation of contaminated sites were $18,000,000 in Nunavut and $27,000,000 in Yukon.

An inventory of all contaminated sites federal agencies are accountable for is kept by the Government of Canada. There are about 18,000 sites across the country but very few of them are large enough to need priority remediation.

    Other focal points

    • For more information on stewardship of the environment go to the Stewardship focal points on this site.

    Technical Notes

    • Class 1 sites are sites with the highest priority for remediation.
    • Assessment phase includes identification of sites, historical review, initial testing, classification and assignation of priority, detailed testing, planning1.
    • Remediation phase includes implementation of remediation plan, measure of success of remediation1.
    • Monitoring phase includes, if required, long-term monitoring and risk management1.  

    For more information

    • More details on INAC’s Northern Contaminated Sites Program can be found at here. This website provides more information on the remediation activities at each site.

    Contact us

    Found an error or have a question? Contact the team at NWTSOER@gov.nt.ca.


    Ref. 1. Northern Contamination Sites Program. Available at https://www.canada.ca/en/sr/srb.html?q=Northern+Contaminated+Sites+Program&wb-srch-sub=#wb-land.

    Ref. 2. Federal Contaminated Sites Action Plan (FCSAP). Available here.

    Ref. 3. Devolution of lands and resources in the Northwest Territories. Available at devolution.gov.nt.ca.

    Updated: May 27, 2015