Contaminants

The NWT has very low levels of pollution compared to many parts of the world. It is important to people in the NWT to know that their environment and their food is safe and healthy. Contaminants are things in the environment that can cause harm to humans and other living things. This focal point tracks potential contaminants in caribou by measuring the levels of selected heavy metals in caribou and in fish. It also tracks the current efforts to remediate existing contaminated sites in the NWT and the number of spills of hazardous material reported in each of NWT’s ecozones.

Air quality and the level of contaminants in the atmosphere are reported in the Air focal point.

10.1 Trends in cadmium and mercury in caribou kidneys

This indicator measures the levels of selected heavy metals (cadmium and mercury) in caribou herds across the Northwest Territories.

Cadmium and mercury in the NWT environment come from both natural and industrial sources. They are absorbed by vegetation and move up the food chain when the vegetation is eatenby herbivores such as caribou. Both metals can accumulate in caribou liver and kidneys. High levels of heavy metal accumulation can cause health problems for caribou and people eating caribou. Ongoing monitoring of levels and changes in contaminants in caribou is an important part of a national program monitoring contaminants in arctic wildlife and the environment to ensure that caribou remains a safe and healthy food source.

Information for this indicator is obtained from research for Sahtu Renewable Resources Board and ENR, in cooperation with the University of Calgary and other partners.

Taking a sample. Copyright S. Kutz.

NWT Focus

Caribou are an important food source in communities across the NWT Caribou and moose meat, including liver and kidney, are a significant part of traditional Dene/Metis diets1.

The concentration of cadmium and mercury in caribou kidneys is measured to monitor whether caribou populations are healthy in terms of contaminant loads, to see if contaminant exposure is changing over time, and to make sure caribou remain a safe and healthy food choice for northerners. Monitoring levels of heavy metals in animals across the north is important to help people better understand natural background levels and exposure to metals in the environment, as well as to better understand changes in contaminants entering the NWT environment through local or global man-made sources⁸.

In the NWT, contaminant levels have been monitored in all major barren-ground caribou herds, and the Norhtern Contaminants Program (NCP) has chosen the Bluenose East and Beverly herds to serve as sentinel herds over time. Sentinel herds are populations more closely studied to provide an indicator of the health of all populations of caribou The Bathurst herd is designated a key herd by CARMA (CircumArctic Rangifer Monitoring and Assessment Network) and has been monitored by the Government of the NWT and its community partnersin recent years under the CARMA program.

Current view: status and trend

Mercury

The level of mercury in the kidneys of NWT caribou is very low and does not pose a health risk to either caribou or people who eat caribou. Both the meat and organs of NWT caribou are safe to eat.  There are naturally occurring sources of mercury in the Arctic environment, and the levels of mercury found in caribou often reflect exposure to these background levels. The primary source of mercury exposure from human activities results from long-range atmospheric transport of mercury from other parts of the world⁷. Sources of mercury include mining, milling and smelting of mercury-containing ores, coal-burning plants, municipal wastewater treatment plants, pulp and paper mills and fungicides. Mercury is a toxic element that accumulates in brain and kidney tissue, and can affect neurological functions and cause poor growth, and kidney damage.Increasing mercury levels have been seen in other arctic wildlife species, in the North, particularly marine mammals, perhaps as a result of a increasing available atmospheric mercury combined with changes in the naturally occurring cycle of mercury in the Arctic environment⁶.  Long-term monitoring of levels over time is important to track current trends.

Mercury level in kidneys of NWT caribou herds, 1992-2008. Threshold for potential effects on caribou is calculated at 130.5 ppm¹⁰.

The levels of cadmium in NWT caribou are not of concern for caribou health, and caribou remain a safe and healthy food choice for northern people. Cadmium levels vary considerably with age (increasing levels in older animals), season (higher in spring than in fall), and sex (higher in female vs. male caribou) but the levels of cadmium in NWT caribou kidneys are generally low.

• "The World Health Organization recommends the cadmium intake should not exceed 72 mg per day or 26,280 mg per year. The average caribou kidney weights 250 g wet wt (...). Given the mean cadmium level 42.6 mg per gram and the mean water content is 77% (of Bluenose caribou kidneys), an individual would have to consume 10.64 entire kidneys per year in order to exceed the recommended level. Subsistence hunters do not harvest the average caribou; they harvest young animals. Conservatively, we suggest that hunters realistically harvest animals -6 years of age and therefore would have to consume 13.2 entire kidneys per year in order to exceed the recommended level. An average family of five would harvest six to eight caribou annually for subsistence purposes. Assuming all kidneys were available and in their entirety that would provide 16 kidneys for five individuals for annual consumption."

Quote from Later and Nagy 2000⁵.

Cadmium is found naturally in the environment. Wildlife exposure to cadmium reflects regional and local differences the type of rocks and soil in the area. In some areas, human activity may also be a source of cadmium. Industrial uses of cadmium include production of cadmium-plated metal, nickel-cadmium batteries, pigment and plastic stabilizers, and mining and refinement of copper, lead and zinc⁴. Long-range atmospheric transport can distribute this cadmium to other places in the environment. Lichens and some other plants absorb cadmium directly from the air and pass it on to the animals that feed on the lichen. Cadmium can accumulate in long-lived herbivores such as caribou, but levels seen in the NWT are not high enough to be harmful to their health. Studies show that the level of cadmium in kidneys for study animals would have to be at like 150 ppm dry weight before some health effects were detected⁹ on animals (e.g. caribou). The levels measured in the NWT are well below this threshold⁷.

Age-corrected cadmium level in kidneys of NWT caribou herds, 1992-2008. Sub-lethal effects threshold according to Outridge et al. (1994) noted at 150 ppm.

Looking forward

It is expected that the level of contaminants in terrestrial mammals will remain low, although the global trend of increasing mercury levels warrants ongoing long-term monitoring.

Researchers are discovering new contaminants in the North, such as PBDEs which are found in flame retardants and fabric treatments. The Northern Contaminants Program tests for a range of contaminants. If new pollutants of concern are detected or increase, they will be monitored to understand how they are being brought to the North and what they mean to the Arctic environment. If a new contaminant appears in the NWT that has an effect on wildlife and is of concern to people, it could be included in the State of the Environment Report.

Looking around

The Northern Contaminants Program (NCP) is a national monitoring program that tracks contaminants in the air, water, wildlife and other parts of the arctic environment. As part of this national initiative, the Arctic Caribou and Moose Contaminant Monitoring Program is a collaborative study being done in the NWT, Nunavut and the Yukon to measure contaminant levels in selected caribou herds across the north over time to track changes in contaminant levels. This project is coordinated by a contaminants specialist in collaboration with wildlife biologists and community members in each jurisdiction. Samples are collected in collaboration with local hunters and community organizations, coordinated by biologists within the GNWT and the NCP, and tested for contaminant levels by a specialized analytical laboratory (Environment Canada’s National Laboratory for Environmental Testing).

Terrestrial mammals in the NWT are generally found to have lower concentrations of pollutants than animals from more southern species or species that are part of the marine ecosystem⁷. Renal mercury in caribou does not appear to be increasing in the Porcupine herd (Yukon)⁶.

Cadmium levels are naturally higher in the southern Yukon. Analysis of caribou teeth from 5000 years ago indicate that one caribou herd from the Southeast Yukon had higher cadmium levels then than now. This is likely due to a shift in habitat over that time. The area is still rich in cadmium, but no longer has an abundance of willows which tend to concentrate cadmium in soil and make it available to herbivores.

Find more

• For more information on Northern Contaminants Program and the Canadian Arctic Contaminants Assessment Reports visit http://www.ainc-inac.gc.ca/nth/ct/ncp/index-eng.asp
• For more information on CircumArctic Rangifer Monitoring and Assessment Network go to http://www.rangifer.net/carma

Updated September 2011

10.2 Trends in environmental remediation of contaminated sites

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

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

Details on expenditures are obtained from Indian and Northern Affairs, Northern Contaminated Sites Program¹¹ and from the Federal Contaminated Sites Action Plan (2005-current)¹².

NWT Focus

Work and costs related to the environmental remediation of abandoned military sites, oil-gas exploration camps, and mines in northern Canada have mostly 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

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, and 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 following private sector bankruptcies due to falling mineral prices¹¹. 

Total expenditures for all sites in the NWT. Values include Nunavut prior to 2000 inclusive, and are for NWT only after 2000. Source courtesy of 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 in the past decade.

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

(In 2008-09 and 2009-10) "The NWT experienced significant delays at a few major sites including the Colomac and Giant Mine sites. At Giant Mine, the Program 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."

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

Looking forward

Past experience and the rapidly rising costs related to cleanup and remediation of industrial sites are pressures for higher standards in 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, climate change introducing uncertainties in access and in environmental changes, and evolving jurisdictional landscape¹¹.

Looking around

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

The federal government keeps an inventory of all contaminated sites for which federal agencies are accountable. There are about 18,000 sites across the country but very few of them are large enough to need priority remediation.

Find out more

• More details on INAC’s Northern Contaminated Sites Program can be found at http://www.aincinac.gc.ca/ps/nap/consit/index_e.html. This website provides more information on the remediation activities at each site.

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, planning¹².
• Remediation phase includes implementation of remediation plan, measure of success of remediation¹².
• Monitoring phase includes, if required, long-term monitoring and risk management¹². 

Updated September 2011

10.3 Trends in spills of hazardous material

This indicator tracks the number of hazardous material spills in each ecozone of the NWT. Hazardous material includes any substance that may include contaminants, such as hydrocarbons or metals. Spills are reported within 24 hours, investigated, and the information on each event is compiled.

Information for this indicator is obtained from ENR- Environmental Protection in the Hazardous Materials Spill Database with analysis from annual “Spills in the Northwest Territories” reports.

NWT Focus

Northern ecosystems are fragile. For example, petroleum will degrade very slowly in cold climates, increasing risks of exposure to wildlife and plants. Different types of activities are linked to different types of spills, each with their own material and levels of risk to the environment.

• “The risk of petroleum spills is associated primarily with the transport and storage of fuels for community and industrial needs. To service the needs of remote coastal and river communities, barges and other large marine vessels provide bulk fuel and supplies. Communities located along highway systems are provided with petroleum by tanker truck. Once delivered to communities, mine sites and other locations, the large volumes of petroleum must then be stored for eventual use in vehicles, furnaces and electrical generators."
• “Depending upon the size and number of years a mine operates many thousands of tonnes of waste rock and tailings may be produced. Unless mining companies carefully control the discharge of water from their tailings ponds, metal and sediments from these ponds can affect the aquatic environment downstream for many years. If a tailings pond is allowed to become dry, tailings dust can also be distributed to surrounding land and water by the wind. There are also significant potential impacts from mining operations as a result of the release of metal-bearing wastes. The potential for contamination comes from the weathering of waste rock and rock exposed during the mining activities as well as accidental spillage of mill tailings. Exposure of iron pyrite and other sulphur bearing minerals to atmospheric oxygen in the presence of moisture leads to acid weathering reactions. These reactions could lead to acid mine drainage and the continual dissolving of metals from waste rock and tailings. This leachate is a potential long-term source of metals to the environment where they can be taken up by plants and animals”.
• "The main emissions associated with oil and gas activities are the discharge of drilling wastes, atmospheric emissions and accidental spills of petroleum. It is common industry practice to dispose of waste drilling fluids on land into sumps adjoining the oil rig. These wastes contain various pollutants ranging from metal salts to petroleum hydrocarbons.”

Quotes from “Pressures on the Arctic ecosystem from Human Activities, 1998³.

Current view: status and trend

In terms of total amounts spilled in the NWT annually, the highest (92%) is of wastewater; the remainders are of fuel oil, various chemicals such as antifreeze and glycol-based products for vehicles, lube oil and other carbohydrates. Wastewater includes sewage, salty ground water brought to the surface by oil-gas extraction, and mine tailings.

Most spills are associated with the mining sector (35% in 2007), governmental activities (19%), oil/gas sector (14%), private activities (7%) and transportation (7%)². Most spills are of fuel oil (30% in 2007) in communities, and are of very small amounts (less than 100 litres). The number of spills increased rapidly from 2000 onward. Changes in reporting protocols for the mineral, oil and gas exploration and development sectors starting in 2004-05 resulted in a decreased in reported small spills (0-100 litres). Small spills mostly involve blown hydraulic lines or leaks from heavy equipment and haul trucks and smaller industrial vehicles such as pick-ups leaking engine and transmission fluids.

Most of the increase in number of spills larger than 100 litres during the past decade is linked to increasing mining development in the Southern Arctic and Taiga Shield, north of Yellowknife.

Looking forward

Changes in the number of spills of hazardous material occurring each year correspond to changes in the NWT’s resource-based economy. Trends in spills larger than 100 litres may rapidly decrease with reduced activities in the mining and oil-gas sectors. However, efforts to reduce the number of potential spills with more efficient prevention and education programs are under way. Developing clean-up technologies in extremely cold and remote environments remains a challenge.

• “At present, technology for cleaning up spilled petroleum is not adequate to remove oil from icecovered waters and there is the potential for a major environmental disaster within arctic fresh and marine waters if a barge or tanker was to spill its petroleum cargo. Although highway tanker trucks carry a significantly smaller volume of fuel than do barges or tanker ships, the increasing volume of truck traffic along northern highways and ice roads continue to threaten terrestrial and aquatic environments located adjacent to these roads.”

Quotes from “Pressures on the Arctic ecosystem from Human Activities, 1998³.

Looking around

The Arctic Council’s Emergency Prevention Preparedness and Response (EPPR) working group was established to foster cooperative work among Arctic countries on environmental protection and sustainable development in the North. This working group developed risk analyses and field manual to help reduce the risks associated with oil spills in the Arctic Ocean.

Find out more

• More details on the NWT Hazardous Materials Spill Database and annual reports can be found at: ENREP: http://www.enr.gov.nt.ca/eps/environ.htm. Information on the number of spills report before 1990 can be found the document “Pressures on the Arctic ecosystem from Human Activities, 1998.³
• For more information on Council’s Emergency Prevention Preparedness and Response (EPPR) go to http://eppr.arctic-council.org/.

Other focal points

• For more information on industrial activities go to the Human activities focal point.

Updated September 2011

This indicator tracks mercury levels in fish sampled in NWT streams and lakes.

Contaminants such a mercury and others like PCBs, DDT, PBDEs, and organohalogens are being monitored in predatory fish in the NWT. Predatory fish (lake trout, pickerel, burbot, and northern pike) are specially sampled because they have a greater potential for bioaccumulation of contaminants.

Fish muscles and livers are sampled from burbot at the Rampart Rapids, Great Slave Lake and several smaller lakes in the NWT. Fish from lakes have been tested in the Deh Cho (Trout Lake, Cli Lake, Deep Lake, Fish Lake) the Sahtu (Lac Ste. Therese, Kelly Lake) and the Akaitcho (Stark Lake, Nonacho Lake).

Data and information are from Northern Contaminants Program Synopsis Reports with specific data from a study by Dr. Marlene Evans (Environment Canada[S1] ), and from Public Health Advisories issued by GNWT- HSS.  The Northern Contaminants Program monitors long range contaminants in fish across northern Canada.  This includes Yukon, NWT, Nunatsiavut, Nunavik, Nunavut.  Text drafted for this report by Lorna Skinner, AANDC, edited by ENR, GNWT.

NWT Focus

Aboriginal people in the NWT consume traditional country foods such as fish as a mainstay of their diet (see USE OF RENEWABLE RESOURCES focal point) .  Generally, fish is a good source of nutrition and high in protein, Vitamin B and omega-3 fatty acids. The health benefits of eating fish outweigh the potential risks.

Mercury is a contaminant that can be found in fish. Levels of mercury differ from lake to lake and can be due to human activities or to natural causes. 

Current view: status and trend

Increases of mercury in fish have led to Public Health Advisories in the NWT.  Mercury is rising in predatory fish due to long range contaminants from other countries such as China.  Climate change is also a contributor as the longer summer seasons allow for changes in the bioaccumulation of mercury in fish.  Older and larger fish tend to have increased mercury due to the biomagnification over time.    Over the last 35 years temperatures have increased in the Mackenzie Basin approximately 1 C  per decade. (See CLIMATE AND WEATHER focal point).

Trends are showing that levels of mercury and other contaminants are increasing at a greater rate in smaller lakes than the larger water bodies such as Great Slave Lake and Great Bear Lake.

Mercury in lake trout and burbot in Great Slave Lake's East Arm (Taiga Shield) is showing an increase since early 2000. Dr. Marlene Evans, Environment Canada.

A significant increase in mercury in fish from smaller lakes was detetced in Sark Lake (62.46 degrees N; -110.33 degrees W), and Nonacho Lake (61.98 degrees N; -109.46 degrees W). Both lakes are in Taiga Shield south of the East Arm of Great Slave Lake. Data compiled by Dr. Marlene Evans, Environment Canada.

Looking Forward

The NWT will continue to monitor contaminants to ensure northerners are well informed as to their consumption of fish. 

This data is also used to influence international policies on contaminants such as United Nations Economic Commission for Europe Convention on Long-Range Transboundary Air Pollution, Protocols on POP’s and heavy metals and the global United Nations Environment Programme and the Stockholm Convention on POP’s. 

It is important to continue monitoring temporal trends of contaminants in fish to understand why changes are occurring.  International policy on mercury use could influence this trend and the Northern Contaminants Program is compiling all of its mercury data over the last 18 years to support international policy discussions.  Challenges of logistics in the North continue to add to the costs to monitor many lakes and funding is limited.

Find out more

For more information on the Northern Contaminant Program, go to http://www.ainc-inac.gc.ca/nth/ct/ncp/index-eng.asp 

Public Health Advisories can be found at http://www.hlthss.gov.nt.ca/