Base de données de recherche des TNO

Régions: North Slave Region

étiquettes: contaminants, permafrost degradation, metals, thermokarst

Objectif(s): To examine the effects of thawing permafrost on freshwater resources of the Yellowknife area and to examine the role of thermokarst development on natural organic matter and the release of metals (e.g. mercury) and organic contaminants (e.g. polychlorinated biphenyls - PCBs).

Description du projet: This research goal is to examine the role of thermokarst development on natural organic matter and the release of metals (e.g. mercury) and organic contaminants (e.g. polychlorinated biphenyls - PCBs). Sampling for contaminants: Water sampling for persistent organic pollutants (POPs) will be done by passive samplers, consisting of a semi-permeable membrane containing a resin that will extract contaminants from water. This sampler is suspended on a line in the water column between a float and a small weight anchored to the lake bottom. This device is placed in shallow water to slowly sample any hydrophobic organic contaminants in the water column for a period of about 3 months. This passive sampler is totally unobtrusive, and has no environmental impact whatsoever. The researcher will suspend these passive water samplers in the water columns of 20 lakes, 10 that have experienced permafrost slumps in their catchment, and 10 that have not. Water samples will also be collected for later analysis of total nutrients, major cations and anions, dissolved organic carbon, pH, and other basic water quality variables. Food web sampling: The researchers propose that permafrost degradation will lead to higher organic and metallic contaminants in lakes that may in turn bioconcentrate and biomagnify in these aquatic food webs. To test this hypothesis, the researcher will select 4 lakes (2 affected by thawing permafrost, and 2 unaffected) and sample sediments, phytoplankton, periphyton, benthos, zooplankton, invertebrates, and fish from the case-control lake design to determine if food webs affected by permafrost degradation accumulate higher contaminants. They will employ established techniques to identify trophic structure and trophic position in these food webs by identifying stomach contents and stable isotopes of nitrogen and carbon in tissues of the aquatic food web and describe food web biomagnification patterns by relating contaminant concentrations with trophic positions. The researchers will be providing scientific data and publications directly with Indian and Northern Affairs, which has direct contact with Dene communities whom both play a direct role in environmental regulation and education, e.g. the Northwest Territories Cumulative Impact Monitoring Program (NWT CIMP). This research in the North Slave region will be a beneficial extension to current ARI-licensed research in the Inuvialuit Settlement Region, in the Mackenzie Delta upland lakes area north east of Inuvik, NT. It will allow for the comparison of ecosystems above and below the tree line relating to climate change and potentially enhanced contaminant transport, which may demonstrate bioaccumulation and magnification into higher organisms leading to country food supplies. Sharing of information from both regions will be provided to the Aurora Research Institute and College in both Inuvik and Yellowknife. The researchers will be seeking out opportunities to present research and topical issues to the community through the advice of INAC. The results of all components of this project will be communicated in a number of media including, but not limited to, written reports, scientific publications, oral presentations, and poster presentations. Copies of these communications will be made available to the Aurora Research Institute upon completion. The fieldwork for this study will be conducted from June 2, 2010 to August 27, 2010.