Base de données de recherche des TNO

Régions: Sahtu Settlement Area

étiquettes: contaminants, environmental assessment, geophysics

Objectif(s): To further determine the current environmental and physical conditions at 18 additional sites along the Canol Trail and to reduce data gaps and allow development of the appropriate remediation strategies and costs.

Description du projet: The purpose of the Phase II ESAs is to further determine the current environmental and physical conditions at 18 additional sites along the Canol Trail and to reduce data gaps and allow development of the appropriate remediation strategies and costs. This will include the identification and quantification of environmental impacts to soil, sediment, surface water and groundwater, as well as the identification and quantification of hazardous and non-hazardous materials at the sites. The field program at the 18 sites will involve the manual excavation of test pits, hand augering, and sampling of sediment, soil, surface water, vegetation and groundwater. The site is at the boundary of continuous/discontinuous permafrost, and therefore the thermally active zone in surficial soils may be expected to be in the depth range of 1 to 2 metres below ground surface. In permafrost terrain, contaminant migration is a near-surface phenomenon, so shallow sampling is warranted and useful. Contaminant pathways via water would be expected along ground surface and through the shallow subsurface (active layer) toward the nearest shoreline. Sampling will be focused to reflect these issues. Soil Samples Samples will be collected using a combination of Dutch auger, hand operated shovel, and a stainless steel trowel. Soil sampling will be used to aid with the interpretation of site petroleum hydrocarbon and metal impacts. Excavation will advance from ground surface to a maximum of 0.3 to 1 m depth. Field Volatile Organic Carbon (VOC) vapour monitoring will be completed for each sample. Subsurface materials will be inspected, described and photographed. Following sampling the borehole will be backfilled to grade. A suitable number of background soil samples will be collected in native overburden materials. Sediment Sampling The collection of sediment samples is proposed to be conducted in nearby water bodies (e.g. rivers and tributaries) from the shore or within the water body with the use of hip waders or an inflatable boat. Depending on the stream conditions (depth, flow rates, sediment type), the sampling would be conducted using either a hand trowel, sampling tubes or a ponar grab sampler. For each sample collected, a depth measurement, GPS coordinates, and description of the sediment (including colour, odour, sheens, staining, water depth, grain size, sample recovery and percent natural organic material), the presence of debris, and any unusual characteristics will be recorded. Surface Water Sampling Surface water samples would be collected along the stream banks, water areas and at locations in which surface water contamination by is suspected. The surface water would be sampled starting at the most down gradient location to the most up gradient sampling location. The surface water samples would be collected using laboratory supplied bottles and by immersing the bottles into the water. During sampling, field parameters including pH, temperature, dissolved oxygen, oxidation reduction potential, and conductivity will be monitored using a hand held water quality meter. Vegetation Sampling In addition to allowing practitioners to determine whether vegetation on a site is directly affected by contamination from soil impacts, vegetation data is essential to both human health and ecological risk assessment. At a minimum, at least two samples of each type of vegetation will be collected in the potentially impacted areas. Background samples from each island will also be collected. If aquatic vegetation is visible, the most evident vegetation will be sampled. Samples will be placed into zip lock bags and sealed and the vegetation will be photographed in its natural setting. Drum Contents If partially filled drums, tanks, and transformers are found on site, their contents will be analysed for “barrel content” (i.e.% glycols/alcohols, PCBs, Cl, Cd, Cr, and Pb) to identify and quantify the contents according to INAC’s “Abandoned Military Site Remediation Protocol, 2008” and the Dew Line Cleanup Barrel Protocol (DLCU). This information will be used to determine the appropriate means of disposing of barrel contents. Designated Substance Survey For the purpose of future demolition of structures and removal of debris, an inventory of site waste in the form of buildings, abandoned machinery, old transformers, miscellaneous chemicals and other debris scattered across the site (including mining equipment) will be completed. The waste materials will be identified as hazardous or non-hazardous to inform potential landfilling decisions. To characterize the waste, laboratory analysis for PCBs, lead, asbestos, barrel content, and leachable lead (PbTCLP) will be conducted. Where PbTCLP analysis is not possible due to the mass of sample required, total lead analysis will be used. Waste materials associated with site buildings, concrete foundations, and dump areas identified in the Phase II ESA will be reviewed in the field and quantified by measuring their in-situ dimensions (length, width and height or depth). All other site waste will be itemized as individual pieces (e.g., drums, scrap metal, scrap wood etc). Geophysical Survey A Geonics Ltd. EM61-HH (hand held) metal detection system will be used to conduct the geophysical site survey of buried waste. The EM61 geophysical technique allows easy determination of the location and lateral extent of buried metallic objects. Each site will be surveyed using a grid pattern determined by the field technician at the time of each survey. Survey lines will be spaced approximately 0.5 m apart and walked at a consistent pace. Electromagnetic responses were noted throughout the course of the survey. Once defined, the edges of any buried waste sites will be clearly marked with flags to enable their boundaries to be georeferenced using the DGPS. All magnetic anomalies will be noted and georeferenced. Site Survey At the beginning of the project a local reference point will be established at each site and marked for any future follow-up work. The local datum will be geo-referenced using a DGPS unit and all sampling locations referenced to the local datum. All sampling locations, monitoring wells and major site features will also be surveyed using the DGPS unit. The location of all land based sampling points, including test pits, and surface samples and surface water sampling locations will be marked in the field with DGPS. The results of this study will be incorporated into INACs consultation process with local community groups. A summary and copy of the final report will be sent to Aurora Research Institute upon completion of the project. The fieldwork for this study will be conducted from August 7, 2010 to December 31, 2010.