NWT RESEARCH DATABASE

Regions: North Slave Region

Objective(s): i) to assess the biomonitoring use of invertebrates to provide information regarding the contamination level of arsenic, antimony, cadmium, zinc as well as of rare earth elements, ii) to understand how amphipods (H. azteca) and zooplankton (Daphnia spp.) adapt to these highly metal-contaminated environments.

Project Description: This licence has been issued for the scientific research application No. 5872. Objectives: i) to assess the biomonitoring use of invertebrates to provide information regarding the contamination level of arsenic, antimony, cadmium, zinc as well as of rare earth elements, ii) to understand how amphipods (H. azteca) and zooplankton (Daphnia spp.) adapt to these highly metal-contaminated environments. For the first objective, the development of environmental tools such as biomonitors to track metal contamination will be essential to better establish the environmental risk of metals including rare earth elements in the region. This issue is of current and great concern given the initial mining activities developed in the Nechalacho mine site, located about 100 kilometers southeast of Yellowknife City. In the short run, such tools will help to determine the spatial and temporal differences to be found in terms of metal contamination as a result of any environmental recuperation the sampled ecosystem can experience for arsenic, antimony, cadmium, zinc. In the long run, these organisms can be useful to follow increased concentrations of other metals such as rare earth elements. For the second objective, the biological responses expected from H. azteca and Daphnia spp. will contribute identifying a more efficient response to metal exposure, and specific detoxification mechanisms in these invertebrates. These expected responses will enable understanding of why these organisms have the potential to display a more effective toxicological response, favoring their adaptation to environmental changes. This study will therefore help understand the long-term impacts of these contaminants on invertebrates, which are an important source of food for fish in the region. For this fieldwork campaign, several samples will be collected in each site : water (surface), sediment (surface), and invertebrates. The water bodies (n = 12) to be studied are : Small lake, Handle lake, Long lake, Jackfish lake, Frame lake, Sammy's lake, Niven lake, Kam lake, Grace lake and other three sites from the Yellowknife Bay. Various water parameters (pH, oxygen concentration, temperature, conductivity, etc.) will also be measured in situ to characterize these ecosystems. Measurements of anion concentrations, organic matter, major cations and trace elements in water samples will also be performed for estimating the form and type of metals present in water (metal speciation). Bioaccumulation data will also be generated by measuring the whole-organism metal concentrations in zooplankton, biofilms, and invertebrates. Such analysis will enable exploration of the relationship between total contamination in water and in sediments of rare earth elements, uranium, thorium and other elements (its species) with the bioaccumulation of these metals in amphipods and zooplankton. In addition, we will compare the responses of organisms originated from those from heavily (Handle lake), moderately (Long lake) and lightly (Small lake) contaminated lakes. Harvested organisms will be brought back to the laboratory alive for reproduction over several generations. Once the desired generation has been obtained, we will test the mortality rate after exposure to contaminants (including arsenic, antimony, cadmium, etc.) to reflect environmental conditions found in the most contaminated lake (Handle lake). In addition to these tests, other parameters (e.g., oxidative stress indicators, reserves, subcellular-metal handling strategies) will be measured in the harvested organisms from different generations to inform us about the impact of this contamination. During this research, the team will be communicating and working with three communities. The first task will be to send a message to each community about our fieldwork plan and objectives. The researchers will encourage a virtual meeting with each community to provide more details and to address the questions they will have about our research project. The team would like to have an initial meeting to discuss the project and explain its importance of our current project, so that we can work out our research ideas together. In order to communicate our data to communities, the hope is to be able to make a short trip to Yellowknife at the end of our research to present our results in person, thus popularizing the content. If this isn't possible, the team will either hold a Zoom meeting or send a popularized text summarizing our results. In addition, researchers will participate in various national and international conferences to share information and results with the community. Regarding the language barrier, in Yellowknife, community members speak English very well for the most part. However, the team is keen to translate presentations and communications into the Dene language to include a wider audience. The fieldwork for this study will be conducted from: June 30 - July 30, 2024