Base de données de recherche des TNO

Régions: Sahtu Settlement Area

étiquettes: contaminants, site remediation, arsenic, hydrology, geochemistry, wetlands

Objectif(s): The objective of this study is to identify how arsenic is bound in the sediments, and determine the role of microbial activity in arsenic mobility.

Description du projet: The objective of this study is to identify how arsenic is bound in the sediments, and determine the role of microbial activity in arsenic mobility. It is anticipated that the results of this research will benefit the design of a constructed wetland, which is expected to be part of site remediation. The researchers propose to sample sediments and surface and pore water from the Ho-Hum Lake wetland adjacent to the Terra mine site and analyse these materials for a range of geochemical and microbial parameters as part of an investigation into how arsenic behaves in the wetland. Pore water (water in the ground where it is not completely saturated) will be sampled using a peeper. This involves inserting what is essentially a small (approx. 1 m deep, 0.5 m wide, and 0.1 m thick) ice cube tray like device into the ground. Each “ice cube space” is covered by a film that allows water to flow in but keeps out sediment. The peepers are left in the ground for 2 weeks. The pore water collected is then tested at a recognized laboratory for a variety of elements. Surface water will be collected by filling small bottles by hand in the wetland. These samples are sometimes preserved using a small amount of weak acid, which is poured into the bottle after collection. The surface water samples will then be analysed for various parameters at a recognized laboratory. Some field tests that will be conducted include measuring the pH, temperature and conductivity of the water. These tests are all carried out on site with a small handheld device. To sample deeper sediments and water a drive-point piezometer will be used. This is similar to hand drilling a very small (1 cm diameter) well hole to depths of 1 m to 2 m. Solid samples will be collected using a sediment corer. All solid samples will be analysed for a suite of metals and carbon. Samples for molecular analyses will be frozen (likely using dry ice) shortly after sampling in order to preserve the DNA. Information will be communicated through Indian and Northern Affairs Canada. Information may also be shared at conferences if appropriate. The fieldwork for this study will be conducted from July 06 to July 31, 2009, between the north shore of Ho-Hum Lake and the south shore of Rainy Lake (Camsell River), around the Terra Mine Site, 65º37’N and 118º07’W.