NWT RESEARCH DATABASE

Tags: contaminants, soil, arsenic, tree core sampling

Objective(s): To determine arsenic toxicity in the environment through time by using trees and soils from the area surrounding the Giant Mine using synchrotron techniques to determine the intensity of toxicity in each year since the contamination started.

Project Description: The goal of this project is to determine arsenic toxicity in the environment through time by using trees and soils from the area surrounding the Giant Mine. This will be done using synchrotron techniques to determine the intensity of toxicity in each year since the contamination started. A 5.1 mm tree borer will be used to take 2 cores from trees within a close proximity to Giant Mine. The research team will samples at 8 sites (1 in each of the 4 cardinal direction away from the mine, at two different distances from the mine). Tree cores will be mounted on wood holders and the rings will be measured and years assigned in the Tree-ring Lab. The same cores will be taken to the Canadian Light Source (CLS) in which scans will be used to determine if/where arsenic is present within the tree core samples (XRF), and the tree core samples and soil samples will be scanned using XANES determining what type of arsenic is being found in both media. The data from the synchrotron will be used to put the levels of arsenic on a timeline illustrating what year contamination started occurring, what ppm the contamination is occurring at, and where in the environment it is most prevalent. The type of arsenic found (XANES) will determine what mode of transfer is occurring for the arsenic to enter the tree (atmospheric deposition, soil contamination, etc.), and if it is chemically altered to do so. The research team will also collect three soil samples at each sampling site (20 grams each of the organic layer, A-horizon, B-horizon if applicable), and will be able to run each of these soil samples through the IDEAS beamline too. Tracing arsenic impacts left from the tailings of the Giant Mine on the surrounding vegetation and environment will help to understand the potential effects on wildlife and humans in the surrounding area of Yellowknife. Results will be disseminated through posters and written communications with local individuals and communities through existing partners within the Government of NWT (Prince of Wales Northern Heritage Centre). The team will also share the information with the Yellowknives Dene First Nation and the Toxic Legacies Project (http://www.toxiclegacies.com/project/the-yellowknives-dene-and-arsenic/). The fieldwork for this study will be conducted from July 25, 2018 to August 31, 2018.