Base de données de recherche des TNO

Régions: Sahtu Settlement Area

étiquettes: contaminants, sediment core sampling, hydrocarbon compounds

Objectif(s): To collect samples and analyze data describing concentrations of PACs in the Mackenzie River and in other water bodies, along a gradient of environmental disturbance.

Description du projet: This licence has been issued for the scientific research application No.5262. The research team are proposing to work with community partners to collect samples and analyze data describing concentrations of Polycyclic Aromatic Compounds (PAC’s) in the Mackenzie River and in other water bodies, along a gradient of environmental disturbance. Specifically, the program will evaluate the relative contributions of two main classes of hydrocarbons – those derived from petroleum (petrogenic) and those derived from combustion of organic matter (pyrogenic) – to PAC mixtures in water and sediments in areas of concern to local communities around Fort Good Hope and Tulit'a. To evaluate cumulative effects of environmental change on levels of PACs in freshwater ecosystems, the team will sample water bodies of local interest, as well as lakes within the Ts'ude Niline Tuyeta Protected Area. For running water, PACs will be measured in surface grab samples and with semipermeable polyethylene membrane devices (SPMDs); PACs in lake sediments will be assessed using sediment cores. Grab samples and SPMDs will be analyzed for PACs at the Biogeochemical Analytical Service Laboratory (BASL). Staff at the Laboratory for the Analysis of Natural and Synthetic Environmental Toxins (LANSET) will age sediment cores, extract PACs from sediment cores, and run chemical analyses on the extracts. Analyses for all other chemical parameters will be conducted at Taiga Laboratories. The key elements of this plan are focused on engaging community partners through collection of samples and ongoing training and continuing to with project partners, including the Government of the Northwest Territories (GNWT), to analyze existing data pertaining to PACs in the central Mackenzie Valley. Working with Guardians in Fort Good Hope to develop deployment and retrieval plans for SPMDs on Loche Lake and 2 – 3 lakes within Ts’ude Niline Tuyeta. Together with Guardians, Environment and Climate Change Canada (ECCC) staff will aim to deploy 5 SPMDS in the first week of June, with retrieval in the first week of July. Surface water samples will be collected at in conjunction with deployment/retrieval, and both water samples and SPMDs will be shipped to (BASL) for analyses. Working with Guardians in Fort Good Hope (and a technical expert) to develop sampling plans for collecting sediment cores from the same lakes as described above. Together with Guardians and a technical expert, ECCC staff will collect sediment cores from the selected lakes, using a Plexiglass gravity corer in the deepest part of the lake. Cores will be sectioned (24 – 36 slices per core) on site, individual slices stored in chemically-clean polyethylene bags, and frozen for transport to LANSET, where the age of sediment intervals will be determined based on radio-isotopes. PACs will also be chemically extracted from each slice, with extracts being analyzed for PACs. Working with local Monitors to facilitate SPMD deployment at a natural hydrocarbon seepage area near Tuli´t’a. Ongoing statistical analyses of GNWT-wide PACs data to evaluate potential relationships between PACs and changes on the land. We will test for factors that may explain variability in PAC concentrations over time. Response variables will include concentrations of select PACs, as well as diagnostic ratios, with forest fire extent and snow pack in the preceding year as key predictor variables. Finally, the team also hope to host an in-person workshop in Fort Good Hope this fall or winter for sharing results and receiving feedback on the program. Results from this project will be shared regularly, through community partners and through community meetings, outreach activities, conferences and professional meetings, and will also be published in a timely manner in publicly available research bulletins, and annual and final reports to funding agencies. The team also plan to discuss findings and share results with the broader group of communities and researchers in the Sahtú Region through regular participation (in-person and teleconference meetings) in the Ne K’? Dene Ts’i?li?Forum (Sahtú Environmental Research and Monitoring Forum). All individuals in the NWT will also be able to access key data through the NWT Discovery Portal and through ECCC’s Open Data Catalogue, or from team partners. The fieldwork for this study will be conducted from July 6, 2022 to August 31, 2022