Sources and fate of microplastics in Great Slave Lake

Regions: Dehcho Region, North Slave Region, South Slave Region

Tags: physical sciences, arctic rivers, water sampling, sediment, Pollutants, Great Slave Lake, sediment core, Microplastics

Principal Investigator: Bourdages, Madelaine (3)
Licence Number: 16865
Organization: Carleton University
Licensed Year(s): 2022 2021
Issued: Jul 20, 2021
Project Team: Madelaine Bourdages, Alexander Jardine, Jesse Vermaire

Objective(s): To quantify microplastic concentration and composition in water, sediment, zooplankton, and air around Great Slave Lake; to examine if microplastic concentrations are greater near communities than the open water of Great Slave Lake; and, to identify whether Great Slave Lake is a source of microplastics to the Mackenzie River.

Project Description: This licence has been issued for the scientific research application No.5004.

The first objective of this project is to quantify microplastic concentration and composition in water, sediment, zooplankton, and air around Great Slave Lake. The second objective of this project is to examine if microplastic concentrations are greater near communities than the open water of Great Slave Lake. The third objective of this project is to identify whether Great Slave Lake is a source of microplastics to the Mackenzie River.

To meet the research objectives, surface water, subsurface water, benthic sediment, beach sediment, zooplankton, and air samples will be collected from Great Slave Lake aboard the R/V Nahidik. Surface water samples will be collected using a 300 micrometers Manta trawl that will be dragged alongside the ship for 20 minutes. Water samples will also be collected below the surface of the water using a peristaltic pump. Both types of water samples will be filtered immediately on site. Approximately 400 g (wet weight) of benthic sediment will be collected from shallower, near shore sites using an Ekman Grab sampler and immediately transferred into glass jars. A short gravity corer will also be used to collect some sediment cores at deeper sites within Great Slave Lake. If the ship goes to shore at any point, beach sediment samples will be collected by scooping sediment from the top 5 cm into glass jars using the jars themselves as scoops. Zooplankton samples will be collected by sieving the surface water for approximately 10 minutes using a zooplankton net. While water and benthic sediment samples are being collected, petri dishes with double sided tape will be opened and left exposed for the duration of water and sediment sample collection to collect data for atmospheric deposition of microplastics.

In addition to the sampling done from the R/V Nahidik, water, sediment, zooplankton, and air samples will be collected around Yellowknife and within Yellowknife Bay using the same methods as previously outlined. Ideally, a small boat will be chartered to allow for this sampling within Yellowknife Bay, however, this will only occur if COVID-19 is no longer a risk to communities and if the work is deemed safe by the community. Alternatively, samples around Yellowknife will be collected from publicly accessible beaches and shorelines. Passive air samplers will also be installed in Yellowknife to collect data for atmospheric deposition over a longer period of time. Filters from the passive air samplers will be changed every week, and all equipment will be removed at the end of the study period.

The research team have communicated with the Arctic Research Foundation about participating in a 2021 R/V Nahidik expedition to collect samples for microplastics, for which they have expressed interest. The team have also discussed sampling in Yellowknife and potential project collaborations with the North Slave Métis Alliance, as well as sampling in Behchoko and project collaborations with The Tli?cho Culture & Lands Protection Department. The team have also reached out to the Yellowknives Dene First Nation, the Akaitcho Territory Government, the Dehcho First Nations, and the Northwest Territories Métis Nation. The research team plan to present the research and all research findings at the Yellowknife Geoscience Forum as well directly to communities. However, the team will only present the research in person after COVID-19 restrictions have been lifted so to ensure the health and safety of community members. A plain language report will be produced at the end of the project and distributed to the communities and organizations involved in the project.

The fieldwork for this study will be conducted from July 20, 2021 to September 30, 2021.