NWT RESEARCH DATABASE

Tags: contaminants, environmental assessment, site remediation, water quality, hazardous materials, soil, vegetation, sediment

Objective(s): To conduct Phase II Environmental Site Assessments (ESAs) at six locations located within the Northwest Territories (NT). To determine the current environmental and physical conditions at each site and to reduce data gaps and allow development of the appropriate remediation strategies and cost estimates.

Project Description: The objective of this research project is to conduct Phase II Environmental Site Assessments (ESAs) at six locations located within the Northwest Territories (NT). The purpose of field investigations at Caribou Point, Crestaurum Mine, Sun-Rose Claim Group, Thompson-Lundmark Mine, Wrigley Point, and Dome Lake is to determine the current environmental and physical conditions at each site and to reduce data gaps and allow development of the appropriate remediation strategies and cost estimates. This work will include the identification and quantification of environmental impacts to all media, including soil, sediment, surface water and groundwater, as well as the identification and quantification of hazardous and non-hazardous materials on the sites. General Methods and Activities The research team will be staying in Yellowknife and visit the sites daily by car, float plane, or helicopter. The field teams will comprise two (2) teams of three (3) individuals each, which include a senior environmental engineer, intermediate assessors with skills in ESA assessments, and field technicians to assist with equipment, photo documentation, field logbooks, media sampling, and mapping. All field equipment will be cleaned prior to arrival on site. All equipment brought on site will be removed after completion of the field work. 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 2 m depth. Field Volatile Organic Compound (VOC) vapor monitoring will be completed for each sample. Subsurface materials will be inspected, described and photographed. Following sampling, each bore hole will be backfilled to grade. A suitable number of background soil samples will be collected. Sediment Sampling Sediment samples will be collected from nearby water bodies (e.g., lakes, ponds streams), from the shore or within the water body with the use of hip waders or an inflatable boat. For each sample collected, a water depth measurement, GPS coordinates, and description of the sediment (including color, odor, sheens, staining, water depth, grain size, sample recovery and % natural organic material), the presence of debris, and any unusual characteristics will be recorded. Surface Water Sampling Surface water samples will be collected from on-site water bodies (e.g. ponds, lakes, streams) at locations in which surface water contamination may have occurred. Sampling would proceed from the most downgradient location to the most upgradient location, by immersing clean, laboratory supplied 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. Groundwater Sampling Monitoring wells will be installed where possible using hand augers, or drive point piezometers. Groundwater samples will be collected for chemical analysis and determination of hydrogeological properties, as well as to confirm/refute the presence of contaminants and free phase petroleum hydrocarbons, where conditions allow. Each monitoring well will consist of a stainless steel cylindrical filter screen protected within a 3/4" (20 mm) stainless steel drive-point body with an internal filter support and a barbed fitting for attachment of sample tubing. The groundwater monitoring and sampling program will include monitoring of groundwater levels and field conditions in all monitoring wells. The samples will be collected using a peristaltic pump. During purging, field parameters including pH, temperature, and conductivity will be monitored and the samples will be collected once these parameters stabilize. This will ensure the collection of groundwater samples that are representative of the aquifer conditions. The water quality meter will be calibrated in the field, prior to use. Waste Rock and Tailings If present, tailings and waste rock samples will be characterized to quantify metal leaching and metal leaching loading rates using shake flask tests and acid-base accounting. The results will be used to estimate the potential loadings to nearby water bodies. Drum Contents If partially filled drums, tanks, or transformers are found on site, their contents will be analyzed for “barrel content” (i.e., % glycols/alcohols, PCBs, Cl, Cd, Cr, and Pb) to identify and quantify the contents according to AANDC’s “Abandoned Military Site Remediation Protocol (INAC, 2008)” and the Dew Line Cleanup Barrel Protocol (DLCU). This information will be used to determine the appropriate means of disposing of barrel contents. 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 elevations of the monitoring wells will be surveyed. The location of all land based sampling points, including test pits, surface samples and surface water sampling locations will be marked in the field with DGPS. Designated Substance Survey For the purpose of potential 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 or shipping 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 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). 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. If aquatic vegetation is visible, the most evident vegetation will be sampled. Samples will be placed into Ziploc bags and sealed and the vegetation will be photographed in its natural setting. The results of this study will be incorporated into AANDCs consultation process with local community groups. A summary and copy of the final report will be sent to Aurora upon completion of the project. The fieldwork for this study will be conducted from August 24, 2012 to December 31, 2012.