NWT RESEARCH DATABASE

Regions: North Slave Region, South Slave Region

Tags: contaminants, water quality, mining impacts, air quality

Objective(s): (1) to determine if the Ekati Diamond Mine is having an effect on the surrounding aquatic environment, wildlife, and air quality; and (2) to provide baseline data for areas where mine development may occur in the future.

Project Description: This licence has been issued for the scientific research application No. 5765. The main objectives of the field work for 2023 will be (1) to determine if the Ekati Diamond Mine is having an effect on the surrounding aquatic environment, wildlife, and air quality; and (2) to provide baseline data for areas where mine development may occur in the future. In winter, water samples will be collected under ice using a 2.5-L Niskin (a cylindrical PVC water sampler). During the week of spring freshet, hydrology and meteorology stations will be set up and data loggers will be serviced approximately once a month until the end of the field season. In summer, sampling equipment will include: multi-parameter water chemistry meters (for in situ measurement of pH, temperature, dissolved oxygen, and specific conductivity), water column samplers (a cylindrical PVC GO-FLO for collection of water samples for laboratory analysis of parameters such as major ions, nutrients, and metals), and sediment samplers (K-B corer and Ekman grab sampler for collection of surface sediment samples for laboratory analysis of parameters such as particle size and metals). Sediment sampling is scheduled to occur every three years; the next sampling period will be in 2026. Lower trophic organism data will be collected as near-shore littoral, mid-depth, and deep-water benthic invertebrate samples. Zooplankton samples will be collected using a conical mesh net towed through the water column. Lake benthos and sediment quality samples will be collected using an Ekman grab sampler (surface areas 0.0225 m2) and additional sediment quality samples will be collected using a K-B corer (top 1-2 cm) to potentially assess the most recent deposition. Depending on the program (i.e., AEMP or PSD), stream benthos samples will be collected using up to two methods, artificial substrates (Hester-Dendy samplers), which consist of nine plates stacked vertically with a total surface area of 0.09 m2, to evaluate short-term colonization; and/or Surber samplers, which will provide a whole community snapshot at the time of sampling. Supporting benthic information including water quality parameters and depth-integrated chlorophyll-a and nutrient data will also be collected using standard lower trophic procedures and lower trophic sampling equipment. Fish and fish habitat information will be collected from lakes and streams within the Ekati Claim Block. Fyke nets, gill nets, dip nets, minnow traps, angling, fish boxes, electrofishing and 1.5 inch, sinking gillnets may be used to sample fish. When required, fish tissue samples will be collected from fish for analyses. Large-bodied fish sampling is scheduled to occur every six years; the next sampling period will be in 2024. A maximum of five lake trout will be lethally sampled for these tissue analyses, the remaining obtained from tissue biopsies taken from live-sampled fish. Round whitefish will be lethally sampled for their tissues and will be generally limited to 20 mortalities per sampled lake. Slimy sculpin, a sentinel species of the AEMP, will also be lethally sampled, but at an interval of every three years, currently set to occur in 2024. A total of 30 slimy sculpin will be euthanized for laboratory analyses including metals. For the AQMP, air samples are collected via Partisol sampler where large volumes of air are pulled through a filter that collects total suspended particulates. This is done in conjunction with continuous air monitoring from one station on site. Dustfall monitoring stations are constructed and situated in accordance with the methods outlined in ASTM D1739-98. Snow samples are collected using a Mt. Rose sampler (corer). Vegetation is monitored using distribution surveys and collected to sample for particulate matter. The WEMP focuses on monitoring wildlife species and habitats that were identified during the Environmental Assessment Review Process (EARP) as being of social or economic importance or of particular ecological or conservation concern (i.e., caribou, grizzly bears, wolves, wolverines, breeding birds, raptors and habitat). The WEMP uses scientific methods and traditional knowledge as a source of information regarding wildlife and local ecology. Changes in Methods The Sediment quality method was changed in 2021 as per the Wek’èezhìi Land and Water Board Decision. Sediment sampling for metals and nutrients are now collected using the EK-core method; a hybrid method based on the concept of bringing undisturbed lake sediments to the surface in a standard 15 cm × 15 cm Ekman sampler and taking core subsamples from within the Ekman using a core template. Core templates (cellulose acetate butyrate, diameter = 51 mm, approximately 15 cm in length) are fitted with a cap that has a hole in the centre (for pressure control). No other planned changes for 2024. Each year, results from the program will be made publicly available through Burgundy and will be presented in a Summary Report that describes highlights of the program. The fieldwork for this study will be conducted from: January 01 - December 31, 2024