NWT RESEARCH DATABASE

Regions: North Slave Region

Tags: water quality, heavy metal, fish health, fish toxicology

Objective(s): i) to carry out toxicokinetic studies to understand the accumulation of metallic contaminants among different tissues and organs; ii) to evaluate the metabolic and biochemical effects of these accumulations by measuring a battery of biomarkers; and, iii) to characterize the mitochondrial biomolecules targeted by these metals in fish (liver) and invertebrates (whole organism) using innovative approaches in environmental metallomics.

Project Description: This licence has been issued for the scientific research application No. 55584. Considering the results obtained in our previous studies on fish and invertebrates, our main goal is to generate a specific knowledge about the implications of metals bioaccumulated observed in the population of northern pike and invertebrates (H. azteca) inhabiting ecosystems located in this mining region. Our specific objectives are: i) to carry out toxicokinetic studies to understand the accumulation of metallic contaminants among different tissues and organs, ii) to evaluate the metabolic and biochemical effects of these accumulations by measuring a battery of biomarkers, iii) 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, we predict that liver will be the organs with the higher metal content among the organs measured, which supports our decision to use it as our organ target for further research. We also expect to observe metabolic and biochemical impairments in fish species as consequences of the chronic exposures of these organisms to a variety of metals including As, Sb. We anticipated that our results will improve our 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. Our 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 researchers planned a field campaign to collect all the aquatic organisms necessary at each study site (Long Lake, Sample Lake, Yellowknife Bay) from 18 June to 28 July 2023. For fish, we will collect 20 individuals per site of the northern pikes. 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. We 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 researchers will meet in person (or virtually) at the start of the project our local partners (local researchers, Yellowknives Dene First Nation (YKDFN) as well as North Slave Me´tis Alliance. Written updates will be provided in in plain language to communities (Yellowknives Dene First Nation, North Slave Me´tis Alliance). In addition to that, the researchers will attend to various national and international conferences to share information and results with the wider community. The fieldwork for this study will be conducted from: October 23 - December 31, 2023