NWT RESEARCH DATABASE

Regions: North Slave Region

Tags: contaminants, bioaccumulation, fish health, metal contamination, biochemistry

Objective(s): To generate a specific knowledge about the implications of metals bioaccumulated observed in the population of three species of fish (e.g., northern pike, lake whitefish, yellow perch) and invertebrates (H. azteca) inhabiting ecosystems located in this mining region.

Project Description: This licence has been issued for the scientific research application No.5278. The main goal is to generate a specific knowledge about the implications of metals bioaccumulated observed in the population of three species of fish (e.g., northern pike, lake whitefish, yellow perch) and invertebrates (H. azteca) inhabiting ecosystems located in this mining region. The specific objectives are: 1) to carry out toxicokinetic studies to understand the accumulation of metallic contaminants among different tissues and organs, 2) to evaluate the metabolic and biochemical effects of these accumulations by measuring a battery of biomarkers, 3) to characterize the mitochondrial biomolecules targeted by these metals in fish (liver) and invertebrates (whole organism) using innovative approaches in environmental metallomics. In terms of outcomes, the research team predict that liver will be the organs with the higher metal content among the organs measured, which supports our decision the use it as our organ target for further research. The research team also expect to observe metabolic and biochemical impartments in fish species as consequences of the chronic exposures of these organisms to a variety of metal including As, Sb. The team anticipated that the results will improve the current understanding of the mechanisms of detoxification and toxicity of metals in aquatic organisms. In addition, these findings may also help explain how some metals induce more significant adverse effects than others. This project has the potential to generate original knowledge to adequately predict the toxicity of metal with a strong predictive value as well as to identify potential markers of significant values in environmental biomonitoring. The research team planned a field campaign to collect all the aquatic organisms necessary at each study site (Long Lake, Sample Lake). For fish, the team will collect 20 individuals per site and per species (northern pike, lake whitefish, yellow perch). For invertebrates, composite samples from Long Lake, Sample Lake, and Handle Lake will be prepared. Metal concentrations in each organ (e.g., liver, muscle, gut, brain) collected will be performed by ICP-MS/MS to get toxicokinetic information about the metal distribution in each individual. The team plan to analyze a series of biomarkers of aerobic, anaerobic, mitochondrial-specific metabolism and oxidative stress to assess the effects of metals once bioaccumulated in aquatic animals. In addition, analytical strategies based on the combination of molecular exclusion chromatography coupled with elemental analysis by ICP-MS (inductively coupled plasma mass spectrometry) will be applied to identify the biomolecules targeted by these contaminants with potential toxic in hepatic mitochondrial fractions previously isolated in each species collected. The research team will meet in person (or virtually) at the start of the project our local partners (local researchers, Yellowknives Dene First Nation (YKDFN)) and during the project (three time during this year). We will provide annual written updates in plain language to communities (Yellownives Dene First Nation). In addition to that, the team will attend to various national and international conferences to share information and results with the wider scientific community. The fieldwork for this study will be conducted from October 21, 2022 to December 31, 2022.