NWT RESEARCH DATABASE

Regions: North Slave Region

Tags: contaminants, environmental assessment, water sampling, aquatic biology, sediment sampling

Objective(s): To address the data gaps at the Thompson-Lundmark Mine site to inform the future Human Health and Ecological Risk Assessments in order to achieve appropriate remedial objectives for the Site to satisfy the Federal Contaminated Sites Action Plan 10-step process.

Project Description: This licence has been issued for the scientific research application No.5312. The objective of this project is to address the data gaps at the Thompson-Lundmark Mine site. The data collected from the field program will be used to inform the future Human Health and Ecological Risk Assessments in order to achieve appropriate remedial objectives for the site to satisfy the Federal Contaminated Sites Action Plan 10-step process. Additionally, the project seeks to provide on-site training to interested members of the North Slave Métis Alliance (NSMA) and/or the Yellowknives Dene First Nation (YKDFN). The field program includes a range of components which are described below: The geotechnical investigation will include a complete field verification to confirm borrow quantity types and estimates, as well as the evaluation of the potential to use already developed, local to Yellowknife borrow sources. Soil samples (3-5 replicates) will be collected using hand tools from each of the five sampling stations (Treasure Island Area of Concern (AOCs), Townsite AOC, Chum Lake Tailings Area, Kim Shaft AOC, and reference area) to achieve horizontal and vertical delineation of contaminated soils and to characterize hydrocarbon staining locations. Grain size and landfill classification samples will also be taken across the site. Proposed soil delineation for known exceedances and characterization of suspected impacted areas include 106 metals samples, 60 Petroleum Hydrocarbons (PHC) samples and 55 Polycyclic Aromatic Hydrocarbon (PAH) samples. Samples of native vegetation will be collected concurrently, including country foods for human consumption (e.g., cranberries, Labrador tea; 25 samples for each species for a total of 50 samples) and wildlife food (e.g., sedge, willow; 25 samples for each of three species for a total of 75 samples). The final species collected will be determined in the field and depend on the plants and vegetation present within the study area. Surface water and sediment samples will be collected from previous sample locations and collected from additional locations for the purposes of delineation. Water samples will consist of grab samples. Depending on water depth, sediment samples will be collected either by hand (shallow shoreline samples) or by grab sampler (e.g., Ponar). Groundwater will be sampled from the existing groundwater well on site and five stainless steel drive-point piezometers will be installed. Samples from new and existing drive-point piezometers for groundwater and/or porewater include 6 dissolved metal samples, 6 PAH samples, and 6 PHC/BTEX (fractions F1, F2, and BTEX) samples. Benthic macroinvertebrate samples will be collected via a Ponar grab sampler and processed with a 500 micrometer mesh sieve bucket. Samples will be collected for community composition (taxonomic analysis of 10 samples) and for tissue analysis (selected invertebrates [up to15 samples] will be submitted for metals, analysis including mercury). Fish communities will be evaluated in a range of collection methods including gill nets, minnow traps, seine net, fyke nets, and/or angling. The final methods used will depend on site conditions encountered and final locations selected for sampling (i.e., minnow traps/fyke nets/seine netting in shallower areas and gill netting in deeper parts of the lake). Water samples will also be collected for eDNA analysis. Following are details regarding proposed fish collection methods: 1) Gee-type minnow traps (1/4 inch galvanized mesh) will be deployed in nearshore and limnetic areas for up to 24 hours and baited with a combination of wet and dry cat food; 2) Gill nets will consist of 6 or 7 - 50' panels or gangs (8' depth) with mesh sizes ranging from 1" to 3.5". Gill nets would generally be set overnight, although the time of sets may be shorter depending on fishing efficiency; 3) Fyke nets would be set in shallow areas and checked and emptied every 24 hours; and 4) A seine net would be used in shallow nearshore areas that are free of obstructions (large rocks, woody debris). The net would be pulled by two individuals through small areas of habitat, brought to shore, and any collected fish enumerated. All collected fish will be weighed and measured (fork length and total length) and observations regarding fish health (e.g., presence of abnormalities, parasites, etc.). Selected forage fish will be retained for tissue analysis (up to 30 samples). Selected larger fish will also be retained for human consumption fish tissues (i.e., filets). Up to 20 samples of lake trout, whitefish, or northern pike will be sampled. Aging structures (e.g., otoliths and scales) will be collected from all larger fish – up to 20 samples. All collected fish retained for analysis will be humanely euthanized prior to sampling and immediately placed on ice for preservation. All other fish will be released alive a point of capture. Samples will be frozen for transport prior to their submission to the lab for analysis. All tissue samples will be analyzed for metals (including mercury). Materials identified in the Site Wide Hazard Assessment Program (e.g., paint, building materials, etc.) will be collected for analysis of hazardous materials. The general allowance for building materials samples include 22 samples for asbestos and 22 paint samples for lead and Polychlorinated Biphenyls (PCB) analysis. Non-hazardous and hazardous waste on site will be quantified to determine quantities required for remedial/site management planning. Acid rock drainage testing will be completed to further the assessment of acid rock drainage potential. Waste rock and tailings will be quantified to determine presence on site. Guidance will be sought from local communities and Elders to inform pre-reclamation/remediation baseline data and evaluate whether potential risk exposure pathways exist and to identify whether monitoring of wildlife and fish in the area is a suitable closure objective. Lastly, a site stability analysis will be conducted through a geotechnical evaluation of existing dumps, landfills, and tailing containment, the establishment of baseline condition monitoring points, and a review of site conditions anticipating effects related to climate change. General allowances for Chum Lake characterization samples: Soil: 7 metals samples; Sediment: 31 metals, 9 grain size analysis, and 9 total organic carbon (TOC) samples (i.e. 3 locations with triplicates collected by Ponar, remaining samples will have 1 sample at surface and 1 at a deeper depth with Ponar); and Surface water: 14 metals samples. General allowance for Thompson Lake characterization samples: Sediment: 15 metals, 15 grain size analysis, and 15 TOC samples (i.e., 5 locations with triplicates collected by Ponar); and Surface water: 5 metals samples. General allowance for characterization samples near the Causeway: Sediment: 15 metals, 15 grain size analysis, and 15 TOC samples (i.e., 5 locations with triplicates collected by Ponar); and Surface water: 5 metals samples. General allowance for background and additional delineation (i.e., step-out samples): Soil: 28 metals and 10 weak acid dissociable cyanide samples; Sediment: 25 metals, 18 TOC, 18 grain size analysis and 3 toxicity samples; and Surface water: 20 routine, 20 TOC, 10 dissolved organic carbon and 20 total metals samples. General allowance for site characterization: Soil: 10 grain size analysis samples and 10 landfill classification samples; Rock: 15 samples for Acid Base Accounting analysis, including Toxicity Characteristic Leaching Procedure, and X-ray Diffraction Analysis; and Rock: multiple samples for element analysis and identification using a handheld X-ray Fluorescence analyzer during field investigation. The leadership of YKDFN and NSMA are aware of the project but engagement has been relatively limited due to ongoing concerns with the COVID-19 pandemic. Both organizations were contacted on for consultation related to the research project. Crown-Indigenous Relations and Northern Affairs Canada (CIRNAC) has prepared a community engagement plan detailing how these groups will be esngaged throughout the research project. This is a draft document that is and will continue to be updated regularly pending outcomes of engagement and discussions with local communities. Any letters of support, which have been requested, that are obtained will be forwarded to the Aurora Research Institute upon receipt. The fieldwork for this study will be conducted from August 22, 2022 to August 31, 2022