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Heavy Metal Analyses of Wild
Edible Mushrooms in the
North Great Slave Lake Region,
Northwest Territories

• Project Leader:

Joachim Obst, Arctic Ecology and Development Consulting, P.O. Box 1888, Yellowknife, NT X1A 2P4; Phone: (867) 669-7084;E-mail: jobst@ssimicro.com

• Project Team:

William Coedy, Taiga Environmental Laboratory, Department of Indian Affairs and Northern Development, Yellowknife, NT; Robert G. Bromley, Whole Arctic Consulting, Yellowknife, NT

Abstract

The analysis of potential contaminants in wild edible mushrooms is a requisite for the safe consumption of fungi by people in the Northwest Territories. From 1997 to 1999, samples of fungi and soil were collected in popular harvest areas of the North Great Slave Lake region, Northwest Territories, including sites exposed to emissions and sites in assumed pristine areas. Laboratory analysis revealed a positive relationship between concentrations of heavy metals in fungi and in soil. Accumulation of heavy metals in mushrooms was species-specific. Because of the high concentrations of metals in edible mushrooms of the North Great Slave region relative to all known national and international standards, extreme caution is urged in the selection of harvest sites. At locations close to roads, communities or mines, mushrooms should not be harvested at all. Mushrooms from the family Agaricaceae should be avoided completely because of their high bioaccumulation properties for toxic metals. Further assessment and public reporting is recommended.

Key Project Message

1. Avoid the consumption of mushrooms from contaminated sites and sites exposed to emissions.

• Project Leader:

Mark Palmer and Pat Roach, Chairs, Yukon Contaminants Committee, Department of Indian and Northern Development, Yukon Region, 345-300 Main St., Whitehorse, YT Y1A 2B5; Phone: 867-667-3139; Fax: 867-667-3341; E-mail: roachp@ainc-inac.gc.ca

• Project Team:

Yukon Contaminants Committee

Abstract

The Yukon Contaminants Committee (YCC) provides direction to the Local Contaminants Concerns (LCC) program. LCC is intended to address concerns raised by Yukon communities and individuals related to suspected local sources of contamination. In addition to planned projects, there are a number of unplanned or “walk-in” issues that arise every year. These issues arise over the course of an operational year and are typically initiated through a phone call or visit by persons with concerns associated with a specific contaminant or location. In some years the volume of these “walk-in” projects can represent a majority of the projects under LCC. 2000-2001 was an atypical year in that most of the program focus was on one planned project. Research conducted on Lake Laberge in 1990-1991 led to the implementation of a consumption advisory for lake trout flesh and burbot livers, which is still in place. LCC decided to revisit the Lake Laberge issue after a catch per unit effort study by the territorial Fisheries Division, in 1999, indicated that the population of lake trout had increased significantly since the previous study in 1991. A research project was initiated with the Department of Fisheries and Oceans, Central and Arctic Region (Winnipeg), which had been involved in previous studies on the lake. The joint program is collecting fish for analysis to determine if contaminant levels in lake trout and burbot have changed in relation to population dynamics. This initial investigation will form the basis for a graduate thesis study to take place in 2001-2002 and 2002-2003.

Other work conducted under LCC was the analysis of lake trout from Mandana Lake provided by the Carmacks Little Salmon First Nation, as part of their implementation of self-government, through the land claims process.

Key Project Message

1. The Yukon Local Contaminants Concerns (LCC) program provides a timely response to local issues, provides a format to deal with unplanned, or “walk-in” concerns, identifies issues that may become major investigations under the Northern Contaminants Program or clean up projects under the Waste Management Program, and feeds into the local regulatory process for dealing with contaminated sites.

• Project Leader:

Glen Stephens, Department of Indian Affairs and Northern Development, Contaminants Division, PO Box 1500, Yellowknife, NT X1A 2R3; Phone: (867) 669-2662; Fax: (867) 669-2833; Email: stephensg@ainc-inac.gc.ca
Allison Armstrong, Dene Nation, PO Box 2338, Yellowknife, NT X1A 2P8; Phone: (867) 873-4081; Fax: (867) 920-2254; Email: denenationkm@ssimicro.com

• Project Team:

Laurie Chan, Centre for Indigenous Peoples’ Nutrition and Environment, McGill University, Montreal, QC;
Olivier Receveur, University of Montreal, Montreal, QC; Bob Dabeka, Health Canada, Ottawa, ON;
William Hendershot, Department of Natural Resource Sciences, McGill University, Montreal, QC

Abstract

This project is a follow-up to a previous study investigating arsenic in berries which found elevated levels in berries on mine sites. This study used exposure and dietary information from the previous study, and determined the type of arsenic present and its bioavailability. From this, risks to consumers from arsenic in berries were assessed and found to be minimal.

Key Project Message

1. Arsenic (As) in berries does not pose a significant health risk to consumers.

• Project Leader:

Norman Snowshoe, Gwich'in Tribal Council, Box 1509, Inuvik, NT X0E 0T0, Phone: (867) 777-4869, Fax: (867) 777-4538, Email: snowshoe@inuvik.net

Sam Stephenson, Department of Fisheries and Oceans, Box 1871, Inuvik, NT X0E 0T0, Phone: (867) 777-7503, Fax: (867) 777-7501, Email:StephensonS@dfo-mpo.gc.ca

Abstract

Due to continued concerns from Fort McPherson, NT residents regarding the safety of eating fish from the Peel River, a baseline study to determine the extent and type of possible contaminants present was conducted in 1999. A total of 30 fish, including ten each of inconnu (Stenodus leucichthys), broad whitefish (Coregonus nasus) and burbot (Lota lota), were examined for a suite of heavy metals and organochlorines. All fish were captured by local fishermen at traditional fishing sites along the Peel River. Analysis shows that cadmium and lead levels were below detectable limits among all three species. Broad whitefish had the lowest quantities of heavy metals. The largest inconnu examined had an elevated mercury level. Two inconnu and one burbot had arsenic levels that exceeded consumption guidelines recommended by Agriculture and Health Canada.

Organochlorines were typically at low levels in inconnu and broad whitefish. Only burbot possessed high toxaphene levels and recommendations are made as to the safe amount that can be consumed per week. Because burbot are mainly eaten seasonally, it is unlikely that short-term consumption will cause a health risk. Based on the results of this study, these fish species from the Peel River are safe to eat. No additional study is required at this time.

Key Project Message

1. This study indicates that inconnu, broad whitefish and burbot from the Peel River are safe to eat.

Melissa Stoddart, Gameti First Nation Band, (GFNB), P.O. Box 1, Rae Lakes, NT X0E 1R0; Phone: (867) 997-3441; Fax: (867) 997-3411; Email:mejstoddart@yahoo.com

Alfred Arrowmaker, William Chocolate and Francis Quitte, GFNB, Rae Lakes, NT; Doug and Lou Rankin, Rae Lakes, NT; Scott Foster, Grand Valley, ON

Abstract

This study investigated the presence of mercury and other metals in fish from two lakes in the Dogrib region surrounding Rae Lakes, Northwest Territories. In each lake, 10 muscle and liver samples were obtained from each lake trout (Salvelinus namaycush) and round whitefish (Prosopium cylindraceum). Each fish was weighed, measured for fork length, and sampled for aging structures (otoliths) to evaluate the relationship between age/size and levels of mercury in the fish. The metal levels measured in the fish were compared with levels that are considered safe for consumption. Many of the metals were found to be in low concentration and below detection limits. In both lakes, mean mercury levels in lake trout muscle and liver were higher than in round whitefish. Some lake trout in both lakes had muscle or liver mercury levels that exceeded the levels recommended by the Canadian guidelines for chemical contaminants in fish.

Key Project Message

1. Most metals (e.g. cadmium, cobalt, lead, iron, arsenic) in whitefish and lake trout from two lakes in the Dogrib region surrounding Rae Lakes, Northwest Territories (NWT), were found to be below detection limits and/or in low concentration.
   
   
2. Lake trout had mean mercury (Hg) levels in both muscle and liver that are higher than those found in round whitefish.
   
   
3. Several lake trout had muscle or liver tissue Hg levels that exceeded the levels recommended by the Canadian guidelines for chemical contaminants in fish.
   
   

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